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ABSTRACT

THE APPLICATION OF HYDRAULICS TO THE
DIRECT HARVESTING OF EDIBLE BEANS

by John Stevens Bolen

This study was undertaken to investigate (l) certain
Operations to which rotary hydraulic power would readily
adapt, and (2) possible methods of harvesting edible beans
directly.

The solution of problems experienced with harvesting
of edible beans appears to be very dependent upon the
ability to develop a direct—harvesting mechanism-which
can satisfactorily reduce field losses and decrease
weathering losses.

Previous direct-harvesting experiments utilizing a
rotary cutting disk prompted a further investigation of a
mechanism utilizing the rotary disk principle.

The investigation included the development of a
double-disk cutting unit which utilized a lightweight,
flexible hydraulic drive system.

Included in the investigation were the determination
of (l) gathering losses as affected by operating height,
(2) plant movement as affected by disk speed and ground
speed, and (3) the power required as affected primarily

by Operating height.

John Stevens Bolen

The basic one—row mechanism consisted of two
hydraulically-driven, virtually horizontal, overlapping
13 l/2—inch disks, rotating in Opposite directions at
speeds ranging from 400 to 700 RPM and 500 to 1000 RPM.

Initial tests indicated that best cutting results
were obtained with the slower rotating disk containing
eight, evenly spaced notches, with each notch about one-
half—inch long and one-fourth—inch deep.

The mechanism, as designed, was intended to be
mounted on the front edge Of a grain combine table to
facilitate the harvesting of edible beans in one trip
over the field.

The grain losses experienced with the cutting
mechanism were at least comparable to losses experienced
with conventional harvesting methods in the same test
area.

With operating heights at which the cutting disks
were at or below the surface of the soil about 65 per cent
of the time, gathering losses experienced were about 2.5
per cent of the pre-harvest yield. This compared with
gathering losses of about 8.8 per cent of the pre-harvest
yield for conventional methods in the same area.

Shattering losses were minimal. Most Of the gather—
ing losses were a result of the pods being cut Open.

The measurement of rearward plant movement indi-

cated that rearward plant movement was directly

John Stevens Bolen

proportional to the ratio of peripheral disk speed to
ground speed and as this ratio increased, plant movement
in a rearward direction increased.

At operating heights where the cutting disks were
at or below the surface of the soil about 65 per cent of
the time, rearward plant movement of about two to four
inches was experienced with the peripheral disk speed
about eleven to twenty times as fast as the forward
travel speed of the cutting machine.

The total power required to Operate the cutting
disks was about 1.52 HP, with abOut .95 HP required by
the left-hand disk and about .57 HP required by the
right—hand disk at operating heights and oferating
speeds listed above.

Approved 7/ 7' We

Major Professor

Approved (”NM

Department Chairman

THE APPLICATION OF HYDRAULICS TO THE

DIRECT HARVESTING OF EDIBLE BEANS

By

John Stevens Bolen

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Agricultural Engineering

1968

ACKNOWLEDGMENT

The author would like to express his sincere
appreciation to everyone who assisted in any manner in
the completion of this investigation.

Special appreciation is afforded Professor H. F.
McColly (Agricultural Engineering) for his helpful gui—
dance, suggestions and encouragement since the beginning
of the graduate program.

Much appreciation is extended to Professor 0. M.
Hansen (Agricultural Engineering) for his suggestions
and assistance during the construction and testing Of
the mechanism.

Mr. w. Wilkining and his associates of the Hydreco
Division of the New York Air Brake Company deserve a
"thank you" for their assistance in acquiring the neces-
sary hydraulic equipment for the mechanism.

The author is grateful for the assistance of Mr.
AndrzeJ Tabiszewski, Special Research Assistant, during
the construction of the mechanism and the field testing
program. Without his willing assistance and helpful
suggestions, completion of the project would have been

difficult.

ii

The author is also grateful for the cooperation of
Mr. Roland Snider and Mr. Ernest Dalby, on whose farms
the field work was conducted.

Many thanks are also Offered Mr. Glenn Shiffer
and his associates in the Agricultural Engineering Re-
search Laboratory for their kind suggestions and

assistance.

iii

TABLE OF CONTENTS

Page
ACKNOWLEDGMENT . . . . . . . . . . . . ii
LIST OF TABLES . . . . . . . . . . . . Vii
LIST OF FIGURES. . . . . . . . . . . . viii
INTRODUCTION. . . . . . . . . . . . . l
OBJECTIVES . . . . . . . . . . . . U
BACKGROUND INFORMATION AND TERMINOLOGY . . . . 5
Agricultural Hydraulics . . . . . . . 5
Components. . . . . . . . . . . 10
Systems. . . . . . . . . . . . l3
Edible Bean Production. . . . . . . . 17
Status 0 o o o o o o o o o o 0 17
Harvest. . . . . . . . . . . . l8
JUSTIFICATION FOR CONTINUED RESEARCH OF DIRECT—
HARVESTING METHODS . . . . . . . . . 27
STATEMENT OF THE PROBLEM. . . . . . . . . 29
PREVIOUS INVESTIGATIONS . . . . . . . . . 31
Literature Review . . . . . . . . . 3l
AnalySiS O O O O O O O O O O O 0 3S
PRELIMINARY INVESTIGATION OF A ROTARY DISK
CUTTING MECHANISM . . . . . . . . . 38
Requirements Of the Mechanism . . . . 38
Analysis of the Functions to be Performed . AO
Separation. . . . . . . . . . . A0
Conveyance. . . . . . . . . . . 41

iv

Page

Selection of the Basic Design . . . A2
Pertinent Data on the Single-Disk Cutting
unit 0 O O O O I O O O 0 O I 14“
DESIGN AND CONSTRUCTION OF THE FIELD TEST
MECHANISM. . . . . . . . . . . . A6
Basic Design. . . . . . . . . . . A6
construction. 0 O O O O O O O O O 53
Frame Construction. . . . . 53
Disk Construction . . . 5A
Preliminary Laboratory Testing. . . 55
Hydraulic Drive System . . . . . 56
PRELIMINARY FIELD LOSSES OF CONVENTIONAL METHODS 59
Types Of Losses. . . . . . . . . . 59
Procedure. . . . . . . . . . . . 60
RSSUltS o o o o o o o o o o o o 62
CONSIDERATIONS OF AND TEST PROCEDURE FOR THE
FIELD TESTS CONDUCTED. . . . . . . . 6A
Considerations of Test Procedure . . . . 6n
Test Procedure . . . . . . . . . . 65
Preliminary Testing . . . . . . . 66
Gathering Losses . . 67
Direction and Amount Of Plant Movement . 68
Power Requirements. . . . . . . . 69
RESULTS AND DISCUSSION . . . . . . . . . 71
Gathering Losses . . . . . . . . . 71
Plant Movement . . . . . . . . . . 77
Effect Of Operating Height . . . . 79
Effect of Peripheral Speed/Ground
Speed Ratio . . . . . . . 79
Characteristics of Plant Movement. . . 80
Power Requirements. . . . . . . 81
Operational Characteristics. . . . . . 86
Plant and Stalk Condition . . . 86
Cleanliness of Severed Plant Material . 86

Ability to Save Low-Handing Pods
Effect of Soil and Stones on the

Cutting Disks

Effect of Lateral Movement of t
Cutting Disks on Cutting Ability

SUMMARY AND CONCLUSIONS.

SUGGESTIONS FOR FURTHER STUDY.

REFERENCES

APPENDIX.

Vi

he

Page
87
87
88
9O
93
96
99

10.

LIST OF TABLES

Page

Hydraulic System Types for Various Tractor

PTO Horsepower Groupings. . . . . . lA
Edible Beans—-Acreage Harvested, Yield and

Production—-Top Six States, 1959-196“ . 19
United States and Michigan Edible Bean

Production by Commercial Classes, Clean

B3813, 1959-196“ 0 o o o o a o 0 2O
Direct-Harvesting Tests, 1955—56 . . . . 34
Maximum Effective Cutting Angle with a

Single-disk Cutter for Various Operating

Widths. O O O O O O O O O O 0 L15
Maximum Effective Cutting Widths for

Various Disk Sizes and Maximum Cutting

Angles. O O O O O O O O I O 0 “7
Disk Clearance for Multi-row Units with

Various Row Widths, Disk Sizes and.

Disk Overlaps . . . . . . . . . 52
Field Losses Encountered with Conventional

Harvesting Mechanisms. . . . . . . 63
A Comparison of the Speed and HP Require-

ments of the Cutting Disks . . . . . 81
Additional HP Required as Operational

Time at or Below the Surface is

Increased. . . . . . . . . . . 86

vii

LIST OF FIGURES

Figure Page

1. Diagrammatic Relationship of Cutting Disk
Dimensions . . . . . . . . . . . A8

2. Maximum Effective Cutting Angle and .
Effective Cutting Width for a Double—Disk

Unit . . . . . . . . . . . . . A9
3. Rear View Of Cutting Mechanism and Throat
Clearance Above Cutting Disks. . . . . A9
A. Left—Side View Of Cutting Unit . . . . . 50
5. Right-Side View of Cutting Unit . . . . . 50
6. Front View Illustrating Notched Disk . . . 51
7. Hydraulic Drive System . . . . . . . . 58
8. Gathering Losses Versus Operating Height . . 72
9. Gathering Losses Versus Stubble Height. . . 7A
10. Stubble Height Versus Operating Height. . . 75
11. Plant Movement Versus Operating Height. . . 78
12. Output HP, Right Motor Versus Operating
Height . . . . . . . . . . . . 82
13. Output HP, Left Motor Versus Operating
Height . . . . . . . . . . . . 83
1A. Output HP, Total Versus Operating Height . . 8A
15. Proposed Multi-Row Mounting on Combine Table. 95

viii

INTRODUCTION

When one reviews the history of agricultural
tractors in the United States, it is noted that
hydraulics made its first notable impact in the form
of a hydraulic lift in the mid-1930's. This advance-
ment inltractor design increased the production of the
Operator and the Operating ease of the tractor.

In the 19A0's remote hydraulic power was intro-
duced to the farm tractor. Hydraulic cylinders Oper-
ated off the tractor hydraulic system were used to
assist in raising pull-type implements. This inno—
vation was the first transfer of power from the tractor
to the machine hydraulically.

When comparing the main mechanical and hydraulic
classes of power transmission devices used with agri-
cultural machines, it appears that the capabilities of
the former have been utilized to the fullest extent and
that very few major breakthroughs in mechanical power
transmission will occur. Hydraulic power, on the other
hand, is seemingly on the verge of a major breakthrough

in agricultural usage.

Zimmerman (1966) has shown that the range Of
tractor hydraulic power, as a percentage of tractor
PTO-power, has increased from 10-20 per cent in 1955
to 30-A8 per cent in 196A. This tractor trend indi-
cates the availability of even larger percentages of
hydraulic power and provides possibilities for the use
of hydraulic motors on agricultural implements to pro-
vide mobile rotary power Just as the hydraulic remote
cylinder provides mobile linear power.

There are numerous applications Of hydraulic power
to agricultural machines at present. Much of this power,
however, is used to provide linear motion.

The provision of rotary hydraulic power, in many
instances, is limited by the operating characteristics
of tractor hydraulic systems. For this reason, rotary
hydraulic power has not been used to any great extent on
agricultural machines.

When one analyzes the advantages of hydraulic
motors and the possible operations or functions which
might be performed by hydraulic motors in the future,
one notes that the process Of direct combining Of edible
beans is one of many processes that might accept the.
adaptability of hydraulic power.

It appears that the desire of bean growers to
remove beans from the field as rapidly and efficiently

as possible to reduce weathering losses, harvesting

losses, and Operating costs can best be satisfied by a
method of direct harvesting which does not require dry-
ing time and eliminates one or two trips over the field.
To facilitate a direct-harvesting mechanism to be
mounted in front of the combine, a compact, lightweight
and flexible drive unit in the form of a hydraulic motor

appears to be most desirable.

OBJECTIVES

In View of this, the objectives Of this investi—

gation are twofold. The first set of Objectives is:

l.

The

To investigate the advantages and dis—
advantages of hydraulics as an additional
source Of rotary power for agricultural
implements.

To analyze the different types of hydraulic
systems available on tractors presently being
used and investigate how well the different
types of systems adapt themselves to pro-
viding a continuous source of power for
remote hydraulic motors.

second set of Objectives is:

To investigate the methods that have been
used or might be used in the direct harvest
of edible beans.

TO develop a direct-harvesting mechanism to

facilitate edible bean harvesting.

BACKGROUND INFORMATION AND TERMINOLOGY

Agricultural Hydraulics

After the development of the simple hydraulic lift
and remote cylinder, more advanced technology produced
power steering and power brakes for the convenience of
the tractor Operator. Automatic lift control systems
and draft sensing systems were introduced to provide
weight transfer, more constant depth operation, and
more efficient use of tractor drawbar HP. This again
increased production and allowed the Operator to perform
the job easier and better than before.

Hydraulically actuated transmissions which accom-
plish the changing of speed ratios in tractor transmissions
without declutching have been available for about ten years.
Within the last five years, dynamic hydraulic transmissions,
better known as torque converters, have made an impression
on the tractor market. ’And within the past year, hydro-
static transmissions have made an impression on the
tractor and implement market.

Recently, draft-sensing remote hydraulic power has
become available to maximize tractor drawbar horsepower

with trailing implements.

With the exception Of remote cylinder usage, agri-

cultural implements have not experienced as extensive a

change from mechanical power transmission to hydraulic

power transmission as the agricultural tractor has.

But upon examining the advantages of hydraulic

power transmission, it appears that hydraulics may soon

become a prime form Of power transmission device for

powering more types of agricultural implements.

Listed below are numerous reasons why proponents

of hydraulics have so strongly endorsed the usage of

hydraulic drive mechanisms (7).

l.

Hydraulic power can be transmitted to distant
or inaccessible points which would otherwise
require an extensive system of belting and
shafting to reach. Thus, those applications
in which the power supply is far removed from
where the power is to be applied readily adapt
to various forms of hydraulic power trans-
mission.

The ability of the Operator to control large
forces accurately through a conveniently
located, easily Operated control lever lends
hydraulic power transmission to those imple—
ments which may encounter varying operating

conditions and which may require constant

readjustment to maintain maximum Operating
efficiency.

The flexibility of hydraulic power trans-
mission devices is almost unlimited. Hydraulic
components such as pumps, valves, lines, and
actuators, are compact devices which can easily
be designed into any machine. Thus, hydraulic
power adapts quite readily to the smooth,
streamlined appearance which manufacturers try
to acquire and which is necessary for the per-
formance of certain operations.

Also, the flexibility of hydraulic power
actuators is quite evident when considering
the ease with which actuators can be moved
from machine to machine or to different areas
on the same machine where power may only
occasionally be required. 'The use of a single
remote hydraulic cylinder on several imple-
ments represents a versatile, low—cost source
of power.

Hydraulic systems are self-lubricating. The
only maintenance required is a regular Oil
filter change and an occasional Oil change as
recommended by the manufacturer. Because
hydraulic systems are self—contained units,

completely sealed from the atmosphere, their

Operation in extremely dusty conditions, Often
experienced with farm equipment, is extremely
reliable and requires minimal extra maintenance.
Due to advancements in hydraulic control valves,
control Of actuator speed, direction, and
hydraulic force applied is very precise.
Acceleration and deceleration of the actua-

tors can be readily controlled with the proper
valving thus eliminating any unnecessary wear
or shock loading which might result from un-
controlled movement.

Most present day hydraulic systems have pro—
tective overload devices such as pressure
relief valves which protect the hydraulic
system, source of power, or machine from either
overloading the machine or encountering foreign
objects not normal to the Operation. This fea-
ture eliminates the necessity for slip clutches,
safety clutch adjustments, shear bolts and
shear bolt replacement.

Hydraulic power transmission is a truly safe
method Of transmitting power. Developments in
material construction have enabled hydraulic
systems to satisfactorily retain oil pressures
far above the 1500-2500 psi normally found on

tractors at present. Flexible hoses and

breakaway couplings permit greater ranges of
movement between the tractor and the imple—
ment as compared to mechanical transmission
devices such as PTO Shafts, for instance,
which have limited safe Operating angles.
With hydraulic breakaway connections, power
transmission is automatically and safely
shut off in the event of an accidental separ—
ation of the tractor and implement. This is
not the case with mechanical transmission
methods presently being used.

Of course, there are also problems which do
occasionally exist with hydraulic power transmission
devices. The two main problems are dust, dirt, rust and
corrosion in the system and heating of the hydraulic Oil
to temperatures high enough to cause damage to the pres—
sure sealing components.

Dust, dirt, rust and corrosion can usually be
remedied most easily by observing the manufacturer's
periodic maintenance suggestions. The availability of
a fully-pressurized system including reservoir is also
of assistance in eliminating these problems.

Excessive Oil temperatures, 100 degrees F. or
more above ambient air temperatures, are generally the
result of (1) imprOper design of the system, or (2)

improper analysis of the load requirement and consequent

10

mismatching between available hydraulic horsepower and
horsepower required to Operate the implement at con—

tinuous, full capacity.

Components

 

The main hydraulic components in a hydraulic
system are the pump, valve and actuator.

The hydraulic pump, which is the heart of the
system, converts mechanical motion into fluid flow.

The control valve functions to direct oil from
the pump to the reservoir or actuator.

The hydraulic actuator, found Opposite the hy-
draulic pump in the hydraulic system, is that mechanism
which converts fluid flow into mechanical motion.

The hydraulic cylinder and piston, either single—
acting or double—acting, is the most common type of
actuator found on agricultural implements at present.
Major tractor manufacturers have options available which
allow the purchaser to connect remote cylinders designed
for that tractor into quick-connect couplings at the
rear of the tractor. The most common type of cylinder
application is that of lifting, lowering and holding or
regulating the depth of an implement in the ground.

With the increased use of remote cylinders in the
late 19A0's, the necessity arose for a standard cylinder

with a standard stroke and standard overall length to

ll

mount on an implement with standard mounting points
which required a given stroke to achieve its full range
of operating heights.

This necessity was met in 19A8 when the ASAE set
forth industry guidelines which standardized remote
cylinder and implement mountings for these remote cy-
linders thus enabling greater interchangeability between
various makes and models of tractor and implement remote
cylinder applications.

Remote cylinders are used in those applications
where the operation is only intermittent and the cylinder
is only Operating or moving a small percentage of the
time the entire hydraulic system is in operation. For
this reason, any overloading or mismatching which may
occur between the job being performed and the capabilities
of the hydraulic system is minimized.

Hydraulic motors, the other main type Of hydraulic
actuator, can be likened to a hydraulic pump which is
used in reverse to provide mechanical rotary motion de—
rived from fluid flow. Hydraulic motors do, in fact,
use many of the same parts that hydraulic pumps utilize.

The application of hydraulic motors differs from
remote cylinders in two distinct ways. It is for these
reasons that the use of hydraulic motors has not, as

yet, been readily evident with agricultural implements

(7).

12

First, the addition of remote cylinders to the
tractor hydraulic system posed no real problem as far
as matching the cylinder to the system or the cylinder
to the job mainly because of the relatively low and
intermittent flows encountered.

Matching hydraulic motors to the tractor hydraulic
system and implement is, however, much more critical due
to the continual Operation which may be experienced.

The hydraulic system must have both adequate pressure
and flow to provide the necessary horsepower and torque
output required by the implement under all conditions.

Secondly, hydraulic motors and motor mountings
are as yet unstandardized, as are the implements which
do not have mountings provided. The position of hydraulic
motors as applied to agricultural implements at present
is analogous to that of remote cylinders in the early
19A0's; tremendous opportunities for the use of hy-
draulic motors exist once hydraulic motors and agri—
cultural implements are studied, reviewed, grouped and
standardized to utilize the benefits of rotary hydraulic
power as fully as the benefits of linear hydraulic
power have already been utilized.

In addition to the proper matching of the system
motor and load, the hydraulic system, in order to per-
form prOperly, should provide a means for efficiently

reversing the hydraulic motor with provisions made for

l3

absorbing any overloads which may be imposed on the
motor during severe operation.

Means also must be incorporated within the hy—
draulic system to control speed and force or torque
output of the actuator with ease and also limit actuator
speed to an acceptable level.

The hydraulic system and motor should efficiently
provide the necessary torque to prevent any excessive
heat buildup within the system.

The hydraulic system must be capable of maintain-
ing a satisfactory hydraulic fluid temperature to pre-
vent premature failure of the hydraulic components.

Once these features can be included in tractor
hydraulic systems, the adaptability of the hydraulic
system to the inclusion of remote hydraulic motors
appears to be quite acceptable to agricultural appli-

cations.

Systems

Recently, Zimmerman (1966) conducted a hydraulic
survey Of fifty-four farm tractors with at least 23
PTO HP manufactured by eight companies. Table 1

summarizes his findings:

1A

TABLE 1.--Hydraulic system types for various tractor PTO
horsepower groupings.

 

 

System NO. Of 20-39 A0-59 60-79 80—99 100+
Type Tractors PTO HP PTO HP PTO HP PTO HP PTO HP

Open-center AA 11 1A 8 A 7

Closed-

center 10 2 2 2 2 2

Variable

displace-

ment pump 8 l 2 l 2 2
Constant

displace-

ment pump 2 l l 0 0

 

Eighty-one and one—half per cent of the major
tractors available on the market today are equipped with
open-center hydraulic systems and constant displacement
pumps.

The nomenclature, Open- or closed—center, refers
to the design of the control valve. A system containing
a control valve which allows flow through its center in
the neutral position is an Open-center system. No flow
through the valve when in neutral indicates a closed—
center valve and a closed-center system.

The basic Open-center system is relatively simple
in design; but as the number of functions operated by
this type of circuit increase, the complexity of the
entire system also increases. In order to provide

proper sequential Operation and adequate pressure and

15

flow control to the individual functions, a close match—
ing Of the pump, valve, flow divider and actuator is
required. Due to the complexity, the number Of valves
and actuators which can be added to the system is
limited.

Since Open-center systems are constant displace—
ment systems, the trend of increasing available hydraulic
horsepower through, generally increased pump output re-
quires that additional flow capacity be built into the
system to prevent excessive increases in neutral line
pressures which would cause more heat generation and
horsepower loss in the system.

The remaining tractors, which made up 18.5 per
cent of the total number in the survey, are equipped with
closed-center hydraulic systems.

There are basically two types of closed—center
hydraulic systems being used.

The first type incorporates a small constant—dis-
placement pump which is used in conjunction with an
accumulator and unloading valve to provide a constant
available working pressure and a storehouse of hydraulic
energy in the accumulator.

This accumulator system takes advantage of the
fact that less horsepower is required to operate the

small pump at full capacity for a given period of time.

16

Also, with the low displacement, heat buildup and horse-
power losses due to neutral line pressures are minimized.

The accumulator, when charged, provides flow rates
in excess of pump displacement for a limited period of
time.

The main disadvantage of closed—center accumulator
systems is that they provide relatively high flow rates
for only limited periods of time. For prolonged oper-
ation, the usable flow is only that which is provided by
the hydraulic pump, which is relatively low. Also,
space must be available to mount the accumulator, which
is sometimes rather bulky.

This characteristic would not adapt these types of
systems to those motor applications which require large
volumes of oil.

The second type of closed—center system incorporates
a variable displacement pump with sufficient capacity to
meet the flow and pressure requirements of the functions
when they are Operating yet return to essentially zero
flow when there is no requirement for oil. This feature,
Of course, provides the necessary pump flow for prolonged
operation of hydraulic motors yet minimizes the heat
buildup and energy loss within the system, when in neuv
tral, due to the no flow characteristic of the pump.

Closed-center systems with variable displacement

pumps take up a minimal amount Of space within the

17

machine due to the minimum amount of valving required

and the absence of a bulky accumulator. Furthermore,

the variable displacement feature of these pumps, coupled
with an essentially constant working pressure, allow
actuator speed and force or torque output to be easily

controlled and limited for protection of the machine

(6).

Edible Bean Production

 

Status

Edible bean production in Michigan is important
both to the state and nation.

United States Department of Agriculture statistics
for the six-year period including 1959 and 196A indicated
that A0 per cent of the national edible bean acreage was
harvested in Michigan, and 39 per cent of the national
edible bean production was produced in Michigan.

It was also noted that for the six—year period
previously mentioned, Michigan produced 99.A per cent of
all pea or navy beans, 58.5 per cent of all cranberry
beans, and 27.8 per cent of all red kidney beans produced
in the United States.

Within the state, 91 per cent of the total edible
bean production was navy beans, and 6 per cent Of the

total production was red kidney beans.

18

During this same six—year period, navy beans made
up 36 per cent Of the total United States production
followed by pinto beans with 2A per cent, great northern
beans with 10 per cent, and red kidney beans with 8
per cent (1A).

Further reference is made to Tables 2 and 3 list-
ing statistics which may be of interest with regard to
state and national production figures.

Present bean production is centered in the Saginaw
Valley and Thumb Area. Harvesting Of the crop generally
takes place after the beans and pods have ripened suffi—
ciently, generally, sometime between early September and

the middle of October.

Harvest

Present Operations included in the harvest are:
(l) removing the plant from the ground, (2) placing rows
of plants together in windrows, and (3) threshing.

The operation of removing the plant from the ground
is most often done with a blade—type—puller mounted on a
tractor. The end result of this Operation is removal of
the plant from the ground with the tough taproot still
attached. The amount Of dirt and rocks included in the
plant material by the blade-type puller is dependent upon

how efficiently the depth of the blades can be controlled.

19

TABLE 2.--fidible beans--acreage harvested, yield and production--top six states, 1959-196A.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

State Acres Harvested ”ield/A. Production, Clean Basis
” ' 1000 A. ' lbs. 1000 cwt.
1959
Michigan 509 1260 6A13
California 25A 1AA2 3662
Colorado 211 780 16A6
ldaho 12 1800 221A
New York 89 9A0 837
Nebraska 77 1650 12 0
U. S. Total 1A35 12:0 18’05
1960
Michigan 825 1190 62A8
California 231 1A0} 3100
Colorado 217 820 1736
Idaho 117 1680 1966
New York 96 1270 1219
Nebraska 71 1500 1065
U. 8. Total IADO ICAA 17All
1961
Michigan 5A1 13e0 7358
California 2%; 1333 3356
Colorado 23? 9L0 22A?
Idaho 9S 2020 1923
New York 37 1530 1331
Nebraska 74 1303 1A06
U. 3. Total lAlA 1191 19672
lgii
Michigan 5 3 l. ’ 7392
Californi 213 14?" 323A
Colorado 227 "FT 167]
Idaho 13’ 15}: 1975
New York 77 ;;83 12A2
Nebraska 77 l‘f? 962
U. S. Total :Alh 126} 1?9A2
1953
Michigan SiA 1A": 8585
California 2:: 1378 3325
Colorado l9t 1133 2156
Idaho 9: 1833 1796
New York 82 1180 968
Nebraska 73 1900 1387
U. S. Total 1750 1A5? 19982
19': "
Michigan 613 12A0 7601
California 135 lAEA 2796
Colorado 180 863 15A8
Idaho 3A 1640 12A2
New York 113 1170 1173
Nebraska 67 15c0 1072
U. 8. Total 1383 1252 1737’
U. S. Six-year Average 1AOA 1318 18A81
Michigan Six-year Average 558 1302 7267

 

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J
The next Operation of windrowing may'be performed in

conjunction with the previous pulling Operation or separ—
ately with another trip through the field. Bean windrowers
are designed to gently lift the bean rOws into a common
windrow on clean ground. This windrowing operation

assists in removing dirt and stones included with the

bean plants by the bean pullers. Side-delivery rakes

are sometimes used in place of windrowers, but they do

not function as well as bean windrowers in cleaning up

the plants and attached roots without creating excessive
field losses.

After a usual one-two day drying period, the thresh-
ing Operation is then performed. Many operators use regu—
lar grain combines equipped with a pick-up attachment and
special bean attachments. Special bean combines with
spring-tooth cylinders and concaves designed specifically
for the easily threshed bean pod and easily cracked bean
kernel are available and used by the larger producers.
Bean special combines are also available. These machines,
although much similar to the regular grain machine,
utilize spike-tooth cylinders, perforated grain pans and
special grain elevators to secure a clean, uncracked
product in the grain tank.

Problems and pecularities of the edible-bean harvest

are as follows:

22

Unpredictable, excessive precipitation and
high relative humidity existing after pulling
and before threshing may increase grain loss
and grain damage and consequently decrease
crop value.

The percentage Of man—hours/acre required for
harvesting seems to be much greater than is
required for comparable crops such as soy-
beans.

Severe plugging may be experienced in combining
beans with a rasp—bar machine if the taproot
is not allowed to dry sufficiently prior to
combining; drying speed can also be increased
if the taproot can be lacerated to some ex-
tent by the puller mechanism.

The incorporation of dirt and rocks with the
plant material may induce unnecessary machine
wear and premature failure; it may lower the
value of the crOp due to excessive foreign
material in the grain.

The position of the bean pods near the bottom
of the stalk and close to the soil surface
requires that the stalks be severed from the
ground at or near ground level to reduce field

losses.

23

6. The ease with which the bean pods are opened
requires that removal and conveyance of the
stalks be as gentle as possible to reduce
shattering losses (A).

An example of the problem caused by weather damage
is given by McColly (1958) who reports that in 195A A0
per cent of the crop was lost by spoilage in the windrow
resulting from excessive precipitation during the har-
vest season. He further reports that beans left stand-
ing in anticipation of direct combining had spoilage
losses of the lower pods only. These losses were con-
siderably less than losses encountered with windrowed
beans. It is also interesting to note that the.windrowed
beans had a higher pick percentage, or percentage of un-
desirable material, than the standing beans. This, of
course, would result in a higher market valuezfor the
standing crop, which was later combined directly.

United States Department of Agriculture Statistics
for 1959 indicated that 38.5 per cent of the time re-
quired to crop edible beans in the nation was spent in
harvesting, while only 2A per cent Of the total time was
required to harvest soybeans, a similar crop. Soybeans
were harvested almost entirely by a direct-combining
process in the nation.

These same statistics indicated that 37.5 per cent

and 19.7 per cent of the total crOpping time was spent in

2A

harvesting edible beans and soybeans respectively in
Michigan.

Three man-hours/acre were required for the harvest
of edible beans in Michigan and in the United States,
while only 1.2 man-hours/acre were required to harvest
soybeans directly in the state and nation (5).

The large, tough taproot which generally remains
attached to the plant after pulling must be allowed to
dry out sufficiently to pass through the rasp-bar
cylinder and concaves used in most small grain combines.
Since the large taproot dries slower than the rest of the
plant, the excessive dryness of the beans and pods which
exists when the taproot is sufficiently dry results in
unnecessary shattering losses. Drying time Of the tap—
root and other parts of the root system can be reduced
if some laceration and ripping of the root system can be
accomplished when the plant is removed from the ground.

The abundance of dirt and rocky material in wind-
rowed beans creates an unnecessary hazard to the harvest-
ing machine and may lower the market value of the pro—
duct. As McColly (1958), Asher (1951) and Gunkel (1962)
have reported, rocks at or near the surface of the
ground have created problems in previous direct-harvest-
ing attempts.

It should be mentioned at this point that there is

no reason for Operating in such rocky conditions as are

25

found in areas of Michigan and New York, for instance,
with the rock removal equipment available. Rocks are
not only harmful to bean harvesting machinery but also
create excessive wear on most other machines used in
these rocky areas. The damage to equipment resulting
from rocks can be far greater than the cost of removing
the rocks over a period of years.

The low—hanging position of the bean pods on the
stalk requires that a direct-harvesting mechanism be
Operated very close to the surface of the ground. With
some crops, it is extremely difficult to operate below
all pods without severing the plant below the surface
of the ground due to the ridging which may exist in the
row after planting and cultivating. This condition may
result in ungathered pods or pods which pop Open when
contacted by the severing mechanism.

Asher (1951) reported that the low-hanging pods may
be subjected to mold formation if excessive precipitation
and relative humidity persist for any period of time
after the crop matures. This condition was also cited
by McColly (1958) in bean harvesting experiments con-
ducted in 195A.

The harvestability of edible beans is also dependent
upon the varieties grown.

The two main types of edible beans grown in Michi—

gan are the bush-type and vine-type varieties.

26

The bush-type bean includes the Gratiot, Sanilac,
Seafarer and Seaway varieties. The bush-type varieties
are less subject to white mold due to their ability to
hold the pods up off the ground, thus allowing better
air circulation. This characteristic also results in
less damage to the beans from extremely wet weather and
promotes easier harvesting. This characteristic results
in the bush—type varieties being planted in over 90 per
cent of the fields in the prime bean growing areas of
Michigan.

The vine-type bean found in the lighter textured
soils, although not prominent in Michigan, seems to pro-
duce best in the hotter, drier years when pod set be-
comes a problem. Vine—type varieties carry their pods
lower to the ground. Vine-type beans grown in Michigan

include the Saginaw and Michelite varieties.

JUSTIFICATION FOR CONTINUED RESEARCH OF

DIRECT-HARVESTING METHODS

Khan (1952) reports that a survey Of county ex—
tension agents in 1952 indicated a trend toward harvest-
ing methods which would.reduce labor and risk. This
trend has occurred to a certain extent in the Michigan
bean-producing areas of the Saginaw Valley and Thumb
Area. This survey also indicated a desire for a bean
variety more adaptable to direct-harvesting methods.

The work conducted by Gunkel (1962) and others at
Cornell was encouraged by that state's bean commission.
Gunkel's attempts at direct harvesting were successful
but did not create any great changes in New York bean
production methods, apparently for two reasons: (1)
attempts to have the particular pulling mechanism mass
produced were futile, and (2) edible beans did not play
an important part in New York's agriculture and were con-
sidered to be a highly specialized crop in that area.

The Michigan Bean Commission has become interested
in direct-bean harvesting methods and has requested of
Michigan State University that research be resumed in

this area.

27

28

Reports of previous work done in this area are,
in general, quite favorable towards direct—harvesting
methods.

A subjective comparison of conventional pulling
methods and direct-harvesting methods indicated that
direct—harvesting methods should increase profit by re—
ducing the Operating costs of the harvest and by re—
ducing the field losses and pick percentage of the

crOp due to inclement weather during wet years.

STATEMENT OF THE PROBLEM

When one reviews the previously discussed problems

and peculiarities of the edible bean harvest, the require-

ments for a direct—harvesting mechanism become more evi-

dent.

1.

These requirements are as follows:

It_should reduce the man-hours/acre required
to harvest a crOp as compared to conventional
pulling methods.

It should allow the crOp to be combined with

a rasp—bar type machine immediately after
removal from the ground to reduce weather
damage.

It should maintain the crop in a condition
which is as dirt—free and rock—free as
possible.

It should be able to gather all pods, especi-
ally low—hanging pods, with a minimal amount
of grain loss.

If the mechanism is to be mounted on the front
of a combine, which is most desirable when it
is considered that this would reduce the number
of trips required over the field, it should be

light in weight so that excessive load is not

29

30

applied to the table of the machine and short
in operable length so that it does not extend
too far forward from the table creating visual
and/or structural problems.

It should be relatively inexpensive and com-
parable in use to other attachments used with
small grain combines; i.e., pick-up or corn-
head attachments.

In addition, (a) if a mechanism is to be
positioned on each row, as Opposed to a full
length cutter bar, it should be capable Of
functioning satisfactorily within a given
range to either side of that row; and (b)

the mechanism should be readily adjustable as
needed to maintain maximum Operating efficiency

in various crop and soil conditions.

PREVIOUS INVESTIGATIONS

Literature Review

 

Asher (1951) conducted research into direct—bean
harvesting methods using a combine cutter bar mechanism
with various auxiliary attachments.

Best results were Obtained with a parallel-bar
reel attachment and pea—type guards on the cutter bar.

Asher concluded that this direct—harvesting method
was superior to conventional pulling methods when used
with bush-type beans under all conditions and with vine-
type beans only under adverse conditions. The reasons
given for superiority of the cutter bar mechanism in-
cluded minimized weather risk and reduced labor costs.
Field losses were approximately the same for both methods.
Under the wet, adverse conditions with vine—type beans,
the direct-harvesting method proved superior because the
cutter bar losses incurred included those beans near the
ground which were subjected to weather damage and be—
came moldy which raised the pick percentage and lowered
crop value.

It might also be noted that in Asher's report

continual reference was made to the unfavorable

31

32

and unpredictable weather conditions which persisted

during the harvest, sometimes delaying intended Opera—

tions for two to three

Khan (1952) also

tests in 1950 and 1951.

cerned with four types
by certain variables.
cluded:

Cutter bar loss:

Cylinder loss:

Separating loss:

weeks.

conducted edible bean harvesting
These tests were basically con-

of losses as they were affected

These losses, as defined, in—

All grain, loose or in pods,
left on the ground by the
machine and never passing
through the machine

Unthreshed grain left in the
pod but carried through the
machine

All shelled or loose grain
carried over the separating and
cleaning mechanism and lost out

the rear of the machine

One of the four variables involved in the harvesting

tests was the difference in losses resulting from direct

Versus windrow harvesting Of the crop.

Results of these tests with other variables rela—

tively constant indicated field losses as a per cent of

preharvest yield to be 22.7 per cent for a direct-

harvesting mechanism utilizing a reciprocating cutter bar.

33

Tests for a machine equipped with a conventional pick—
up attachment yielded a loss of 17.2 per cent. Test
conditions were listed as humid weather with a wet crop.

Direct combining a wet crOp resulted in cutter bar
losses of A8.0 per cent of the total field loss but only
23.9 per cent of the total loss when the crop was dry.

As explained by Khan, high cutter bar losses with
a wet crop were the result Of the pods hanging very low
and being left in the field. With a dry crop, although
the losses were less, the percentage of shattered grain
popping out of the pods was higher.

As a comparison to what some people might consider
as ideal, in one series of tests a man walked in front
of the machine manually pitching windrowed beans into
the conveyor. Cutter bar losses, as defined, were 1.7
per cent and 2.3 per cent Of the preharvest yield for
wet and dry crOps respectively.

Khan concluded that of the three types of losses
listed, the one loss which was predominant in almost all
testslwas the cutter bar loss which claimed about one—
half of the preharvest yield in some instances.

McColly (1958) reported that A0 per cent of the
crOp was lost in the windrows due to inclement weather
during the latter part of September, 195A.

:Direct harvesting tests by McColly in 1955 and

1956 in which he compared direct-harvesting with a

3A

cutter bar to direct harvesting with a single-disk
rotary cutter followed by a pick-up attachment on a
combine indicated increased gathering efficiency with
the rotary cutting mechanism.

Reference is made to Table A which provides a
comparison of the results Obtained with a cutter bar

and a rotary cutter by McColly in 1955—56.

TABLE A.——Direct-harvesting tests, 1955-56.

 

Harvesting Condition

 

 

Harvesting Good Dry
Method Yield Loss Loss Yield Loss Loss
Bu/A Bu/A % Bu/A Bu/A ' %
Direct cut
w/cutter
bar 26.3 2.37 9.03 30.1 7.0 23.22
Cut w/
rotary
cutter,
pick—up 26.3 .A7 1.50 30.1 3.A 11.29

 

 

It was also reported that losses with the rotary
cutter were reduced to 3.0 per cent under dry conditions
if the machine were operated in the morning when a dew
was still present.

Gunkel and Anstee (1962) conducted direct-harvesting
experiments during 1961-62 which investigated various

mechanisms designed to pull the plant from the soil.

35

Their comparisons of experimental pulling devices
to conventional pulling methods were based upon conven—
tional method losses of 2.0A Bu/A and 2.9 Bu/A in 1959
and 1961 respectively. The conventional method which
they discussed included pulling, raking, and picking up
the crOp.

One device utilizing a rubber fingered V Belt on
each side Of the plant resulted in pulling losses of
1.57 Bu/A which was considered to be significantly lower
than conventional losses in 1959. Work in 1960 with
this device resulted in losses of 2.62 Bu/A.

Experience in New York at this time indicated the
rotary cutting device was unacceptable due to the large
amount of rocks at the soil surface which rapidly dulled
the cutting edges.

During 1960, a four-belt puller was also used,
but losses of 2.87 Bu/A were considered excessive.

Best results were Obtained with a flat-belt puller
in 1961. The optimum belt speed to ground speed ratio
resulted in minimal losses of 1.0 Bu/A. During this
same year, the same rubber-fingered V Belt device tested

in 1959 lost about 2.A Bu/A.

Analysis

The increased cutter bar losses resulting from
direct-harvesting methods are, of course, reductions in

the net profit returned to the landowner, but the

36

labor-saving method of direct harvesting and condition
of the direct-harvested product may tend to offset
field losses and increase net profit returned to the
landowner. Reference is made to the reports of McColly
(1958) concerning the high pick percentage in windrow—
harvested beans as compared to direct-harvested beans
in moist weather particularly.

The effect of direct-harvesting methods becomes
more complicated when the overall combine operating
efficiency is evaluated as it is affected by the method
of harvest. Khan indicated this in his evaluation that
cylinder and separating losses increased as the volume
of plant material passing through the machine increased.
This volume is likely to increase with a windrow-harvested
crop which has been pulled.

It must be remembered that McColly's tests con-
cerned with the rotary cutter in 1955—56 were on a two-
phase Operation which included cutting and pickup. Un-
doubtedly, some of the losses reported were a direct re—
sult of the pickup mechanism and not the rotary cutter.

The marked difference existing between losses of
the cutter bar and rotary cutter appear to significantly
favor the rotary cutting mechanism under both wet and
dry conditions.

Flat-belt pullers, which envelOp the entire plant,

investigated by Gunkel and Anstee have not been used

37

extensively, although they function well. Correspondence
with Gunkel indicated the device could readily be mass
produced and mounted but this was not done because Of

the relatively insignificant status of New York State
edible bean production. The use of the flat—belt pullers
in rows narrower than 36 inches probably limited their
acceptance also.

Gunkel and Anstee's experience with a rotary cutting
mechanism, unfortunate as it was, could have been more
pleasant had the field been cleaned of rocks as all
fields should be. Other reasons for an experience of
this type, as related by the manufacturer of the rotary
cutting machine, would include improper angle of Operation

or depth of Operation Of the cutting units.

PRELIMINARY INVESTIGATION OF A ROTARY

DISK CUTTING MECHANISM

,—

Requirements of the Mechanism

 

Reports by McColly (1958) indicated that the rotary
cutting disk principle performs satisfactorily under
Michigan conditions. It was reported that combining can
be accomplished directly behind rotary cutting disks with
no adverse effects on the machine.

In view of these reports and in view of the fact
that it does not appear that direct harvesting with a
reciprocating cutter bar can be accomplished without high
cutter bar losses and large amounts of foreign material
passing through the machine, it was decided that the
rotary cutting principle be investigated in detail with
the thought in mind that a rotary cutting mechanism be
developed that could be mounted on the front of a com-
bine to facilitate direct harvesting.

The design requirements of a direct-harvesting
mechanism utilizing the rotary cutting principle for
this type of a crOp would include those requirements as

listed on pages 29 and 30 of this report.

38

39

The application of rotary cutting disks to these

requirements would indicate that:

1.

A rotary cutting mechanism should reduce the
man-hours/acre required for harvest by in—
cluding the pulling and windrowing operations
with the threshing or combining Operation.

A rotary cutting mechanism should enable the
crop to be combined immediately, even with a
rasp-bar type machine, since the cutting
mechanism either cuts off or lacerates the
taproot sufficiently to allow immediate
combining.

A rotary cutting mechanism should leave the
plant material in a condition which is as
dirt-free and rock—free as is possible. In
viewing the operation of a rotary cutting
disk, there was no evidence of foreign
material being mixed or thrown in with the
plant material.

A rotary cutting mechanism used in conjunction
with rod-type lifters, if necessary, and
Operated at or near the surface of the ground
should be able to move under all low-hanging
pods.

A series of rotary cutting mechanisms,

hydraulically driven, in-line and close to

A0

the front of a combine table, and short in
operable length should be light in weight and
close enough to the operator to eliminate

any structural or visual problems.

6. A basic rotary cutting mechanism appears to
be relatively simple in structure and, conse—
quently, should be relatively easy to manu-
facture at a cost comparable to other front-
mounted combine attachments.

7. A rotary cutting unit should be capable of
functioning satisfactorily within a given
range which could be easily maintained by the

Operator to either side of the row.

Analysis of the Functions to be Performed
Ideally, a mechanism Of this type should perform two
specific functions: (1) separation of the plant from the

ground, and (2) conveyance Of the plant to the combine.

Separation

 

Ideal separation would include severance of the
plant stem from the root system, thus minimizing the
amount of foreign material and plant material passing
through the combine.

If complete severance is not accomplished, the
root system should be lacerated to such an extent that

it will not promote any plugging at the combine cylinder.

Al

Any foreign material clinging to the roots should be
sufficiently loosened by the cutting mechanism so it
does not remain with the plant.

Ideal separation would, of course, involve a
minimal amount of contact between the bean pods and the
cutting mechanism and a minimal amount Of vibration of
the plant by the cutting mechanism as separation is
accomplished to insure that the bean pods are not acci—
dentally opened, which would cause the beans to be lost

on the ground.

Conveyance

 

Conveyance or movement of the bean plant into the
gathering mechanism of the combine after separation would
ideally be short in distance with as little agitation of
the plant material occurring as is possible.

Ideally, rotation of the cutting disks would impart
sufficient rearward motion to the separated plant to
move it rearward into the combine gathering mechanism;
such as, an auger or conveyor in the combine table. This,
of course, would require that the cutting mechanisms
be mounted close to the base machine and would not re—

quire any additional conveying mechanism.

A2

Selection of the Basic Design

 

The basic designs considered included:

1. A single cutting disk similar to the Hopkins
machine.

2. A single cutting disk with a stationary shear
bar below the disk to provide a cutting or
shearing edge for complete severance of the
plant but requiring that the shear bar be
operated at or just below the surface of the
soil.

3. Two cutting disks with one disk on each side
of the row, rotating in Opposite directions,
with one disk rotating slower than the other
to acquire both a holding and severing action
on the stem of the plant, to reduce shattering
losses.

A. Three cutting disks with two disks on one side
and one disk on the other side of the row with
the paired disks serving to hold the plant
stem as the third disk rotates between them,
severing the plant stem.

The design utilizing the two disks was chosen be-
cause it should function in severing the plant almost as
Well as any of the designs, should not require as much
force to push through the soil as the design utilizing

the stationary shear bar or the three disks, should not

A3

require as much rotational horsepower as the three-disk
design, and should provide a desirable set of controlled
variable conditions in the differing speeds Of the ro-
tating disks.

With regard to the function of conveying of the
plant material to the combine, the ideal situation, as
previously stated, would be that the cutting disks would
impart sufficient impetus to the plants which would move
the plant material directly into the combine table.
Viewing HOpkins' machine in Operation indicated the
plants were moved rearward a short distance.

If rearward movement should not be sufficient, a
reel-type or walker-type feeder could be mounted directly
behind and above the cutting disks to move plant material
away from the cutting disks and onto the combine table.
This addition would, Of course, increase the complexity
and cost of such a unit; and the extra handling would
promote somewhat higher shattering losses.

The third consideration regarding the conveying
Inechmhism would be to mount the cutting unit forward Of
a Eitandard combine pick-up attachment, but again, the
extaca handling and cost involved resulted in this method

onlsz being thought of as an alternative.

AA
Pertinent Data on the Single—Disk
CuttinggUnit

Peripheral speed Of the 26-inch diameter disk at
reported rotational speeds of 500 to 600 RPM would be
3A00 to A080 FPM.

At reported Operating speeds of five to six MPH,
the relation of peripheral disk speed to ground speed,
hereinafter referred to as Peripheral Speed/ Ground
Speed Ratio, would range from 6.A/1 to 9.3/1.

The maximum effective cutting angle, which is
important in the determination of the effective cutting
width or operating width, will hereinafter be defined as
the maximum angle at which material, as it comes in con-
tact with the periphery of the rotating disk and is
severed, is effectively moved rearward over the disk.

With no information available regarding this angle,
an investigation of the desired Operating width, assuming
a safety margin of one—inch on the edge of the disk,
allowed for an approximation of the maximum cutting
angle. Table 5 lists this calculated data for a 26-inch
diameter disk.

Table 5 indicates that for an Operator to have a
reasonably satisfactory Operating range on each row,
the maximum effective cutting angle must be in the area
Of 55-75 degrees, thus allowing a maximum effective

operating range of A.6 to 8.6 inches.

A5

TABLE 5.—-Maximum effective cutting angle with a single—
disk cutter for various Operating widths.

 

Operating
Width,
inches l.A 2.0 2.8 3.6 A.6 5.5 6.5 7.5 8.6

Maximum

Cutting

Angle,

degrees 35 A0 A5 50 55 60 65 70 75

9

.7

80

 

DESIGN AND CONSTRUCTION OF THE

FIELD TEST MECHANISM

Basic Design

 

Considerations in the design of the proposed double—

disk unit included:

1.

Sufficient horizontal overlap of the two disks
to accomplish severance Of the plant stalk.
Allowance for sufficient clearance between the
rear edges of the disks (Opposite the over-
lapped edges) which would Operate on adjacent
rows in a multi-row unit.

An effective cutting width comparable to the
estimate for the single—disk unit presently
manufactured.

Sufficient horizontal clearance between the
driving shafts to allow rearward passage of

severed plant material.

The initial assumption to be made with a unit Of

this type operating under these conditions was that an

overlap of one to one and one-half inches should be

sufficient to separate the upper plant from the root.

system.

A6

A7

Once the overlap was established, the equation
listed below yielded the effective cutting width at
various maximum effective cutting angles for various

size disks. Table 6 illustrates these values. Figure

l diagramatically illustrates the disk overlap, disk
clearance, maximum effective cutting angle and other
pertinent information. Figure 2 illustrates the

maximum effective cutting angle and the cutting width.

Effective Cutting Width = 2(R - 50L - R Cosfi)

Where:
R = Radius of the cutting disks, inches
OL = Overlap of the cutting disks, inches
0 = Maximum effective cutting angle

TABLE 6.-—Maximum effective cutting widths for various
disk sizes and maximum cutting angles.

 

Maximum Cutting

 

Angle, degrees 55 75

Disk Overlap,

inches 1.0 1.5 1.0 1.5

Disk Size, Maximum Effective Cutting

inches Width, inches

12 A.l 3.6 7.9 7.A
12.5 14.3 3.8 8.3 7.8
13 A.6 A.1 8.6 8.1
13.5 A.7 A.2 9.0 8.5
1A 5.0 A.5 9.A 8.9

 

A8

 

 

Y‘ Y
.< - s W e I .
9‘ ‘9‘ I m— Cutting Width
zr » .
A ' >~
, A l 4 '
AT \ :5 A
.- ' R .
/ <0 A“ .
t OL‘T? " \ ’ '
CL \ V

Figure l.—-Diagramatic Relationship of Cutting
Disk Dimensions

A9

 

”09. F170 0 02.

Figure 2.-—Maximum Effective Cutting Angle
and Effective Cutting Width for a Double—

Disk Unit

 

Nay. f3)? 0 dz.
Figure 3.--Rear View of Cutting Mechanism and

Throat Clearance Above Cutting Disks

50

o» “0".- n

v. 0

Utah}

o O

O

O ’O
'0 .

..... .s / . \

 

”07. F170 09 1..

Figure A.--Left Side View of Cutting Unit

 

”9'. Fx/e 00“

Figure 5.——Right Side View of Cutting Unit

51

 

 

Ney. I570 00:.

Figure 6
iew Illustrating N
otched Di
sk

52

The equation expressing the clearance between the

disks' edges opposite the overlap with an in—line multi—

row unit would be as follows:

CL = W - 2D + OL

Where:
CL = Horizontal clearance between disks, inches
D = Diameter of disks, inches
OL = Overlap of the two disks, inches
W = Row Width, inches

TABLE 7.--Disk clearance for multi-row units with various
row widths, disk sizes and disk overlaps.

 

Row Width,
inches 26 28 30

Disk Overlap,

inches 1 1.5 l 1.5 l l.

 

Disk Size,
inches

12
12.5
13
13.5
1A

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Final disk selection was of the 13.5-inch

The average maximum operating width for maximum

size.

cutting

angles of 55 degrees to 75 degrees was 6.625 inches with

an inter—row clearance for multiple units of 2.5 inches

when spaced on 28-inch rows with an overlap of 1.5

53

inches. This overlap will also allow operation of this
unit in 26—inch rows with one—half-inch clearance still
available for in-line multiple units.

This average operating width is comparable to
that of the single—disk machine which had an average
range of 6.6 inches for the above listed maximum cutting

angles.

Construction

 

Frame Construction

 

The construction of the mechanism was such that it
would be no wider than the width of one row yet wide
enough to provide horizontal throat clearance above the
cutting disks and between the disks' drive shafts for
rearward plant movement.

The fore and aft length of the mechanism was limited
as much as possible to reduce the weight of the unit and
increase its compactness.

The height of the mechanism was directly related to
the vertical throat clearance required above the cutting
disks for rearward plant movement.

Overall dimensions Of the unit frame were as
follows:

Frame Width: 21 inches

Frame Length w/floating linkage: 16 inches

Frame Length w/o floating linkage: 8 inches

5A

Frame Height: 2A inches
Cutting Disk to tOp frame height: 26 1/2 inches
Disk diameter: 13 1/2 inches
Disk position, center to center: 12 l/A inches
Disk overlap: l l/A inches
Disks width, overall: 25 3/A inches
Vertical throat clearance between disks and
top frame: 19 3/A inches

Horizontal throat clearance w/o shaft guards:
ll l/A inches

Horizontal throat clearance w/shaft guards:
9 inches

Gauge wheels were installed on one side of the
unit to maintain a specific operating height. An adjust—
ment was provided to vary the height of the gauge wheels
with respect to the cutting disks.

The unit was mounted on a tractor through a parallel
linkage arrangement which permitted vertical movement of
the unit with respect to the tractor due to variations in
the soil surface. The parallel linkage also maintained
the cutting disks at approximately a 5 1/2 degree for-

ward tilt angle as the unit moved up or down.

Disk Construction

 

Power was transmitted from hydraulic motors through
shafts to each of the cutting disks. The cutting disks

were keyed to the bottom of each shaft and were also

55

vertically adjustable to accommodate small changes in
operating height. The vertical clearance existing be-
tween the overlapping disks was approximately .05A
inches for all tests.

The disks themselves were removed from a double—
disk planting unit opener. A very slight concave shape
of the disks required that the lower left-hand disk be
mounted with the concave side up and that the upper
right-hand disk be mounted with the concave side down.

The amount of concavity was found to be l/8—inch

at the center of the disk.

Preliminary Laboratory

Testing

Laboratory tests were conducted to check the cutting
ability of the two smooth disks. It was found that the
lower bean stalks were not cut as rapidly as desired
when hand—fed into the cutting unit. At disk speeds of
about 600 RPM and A00 RPM on the left-hand and right-
hand disks respectively, the cutting time required was
about three seconds.

Consequently, it was decided to notch the cutting
edge of the upper, right—hand disk. Notches were ground
at eight evenly spaced points around the disk. The
crescent-shaped notches were about one-half-inch long
and one—fourth—inch deep. Care was exercised in grinding

to insure that a sharp edge was maintained on the lower

56

edge of the notch. Cutting action was significantly
quicker after notching.

Initial tests indicated that with right-hand disk
speeds at or below 250 RPM, the stalk dropped into the
individual notch and was pinched and/or sheared Off by
both disks. At speeds above 250 RPM, severance appeared
to be the primary result of the notched edge gnawing

away the stalk.

Hydraulic Drive System

The cutting disks were driven by two fixed—displace-
ment gear-type hydraulic motors. The hydraulic motors
were independent of each other to maintain maximum con-
sistency in the test results.

Each motor was driven by a separate fixed—displace-
ment, gear-type hydraulic pump which was, in turn, driven
by a small gasoline engine.

The hydraulic motor speeds could be varied by
regulating the speed of the gasoline engine. This was
the manner in which the disk speed to ground speed ratio
was changed.

The hydraulic motor speeds could also be varied
with respect to each other by a flow control valve which
could be used to divert a portion Of the output flow from
the pump back to the reservoir, thus reducing motor

speed. As can be seen in the hydraulic system diagram,

57

Figure 7, this diversionary valve was in the circuit
which drove the right—hand, notched disk (3, 11).

Hydraulic pump and motor selection was based on
the assumption that the maximum horsepower per disk
would not exceed two HP and that disk speeds within
the range of A00 to 1500 RPM would be sufficient.
System pressure was not to exceed 1000 psi.

With this information, the hydraulic component
manufacturer's literature was used to select the neces—
sary hydraulic pump and motor models that would satisfy
the above requirements.

Two small shafts were mounted above and in front
of the cutting unit. These shafts were driven from the
cutting disk drive shafts at a 1:1 ratio. Two tacho-
meters were then installed on the small shafts to pro—
vide a direct—reading mechanism for checking rotational
disk speed.

A pressure gauge was installed in each hydraulic
circuit to check the operating pressures develOped in
each circuit.

A third pressure gauge was also installed near
the reservoir return line to check back pressure in the
circuits.

The construction Of the unit was such that disk
.heights and speeds could be conveniently changed and

disk speeds and Operating pressures could easily be

determined.

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PRELIMINARY FIELD LOSSES OF

CONVENTIONAL METHODS

Types of Losses

 

During the first and second week of September,
pulling, windrowing and pick-up losses were checked in
various harvesting operations in the Mason, Michigan
area.

Pulling losses were defined as those losses which
resulted from the pulling Operation in which the plant
was removed from the soil. These types of losses in-
cluded any beans removed from the pods as a result of
the pods coming in contact with the pulling machine and
any portion of the crOp left in the ground by a pulling
machine which was adjusted too high.

Pulling losses did not include any beans knocked
from the pods by adverse weather conditions prior to
pulling, sometimes referred to as pre-harvest losses. In
checking, there were no pre-harvest losses resulting from
weather damage.

Raking or windrowing losses included those losses
resulting from raking or windrowing the crop after pull-

ing and prior to combining. These losses were generally

59

60

the result of the crop coming in contact with the rake
or windrower teeth, the soil surface and other plant
material as the windrow was rolled over the ground.

In the Mason area, raking and windrowing were done
in more than one Operation. The reasons for this were
twofold: First, leaving the pulled crop in two- or four-
row multiples allowed for quicker drying before the
final raking Operation united row-multiples into six-
or eight-row windrows for machine combining. Second,
the multiple—raking operation reduced the possibility
of stones being included in the windrow to be combined.

Pick—up losses included any beans or pods left on
the ground as a result of the action of the combine pick—

up attachment.

Procedure

 

Initially, pre—harvest losses were checked by a
visual inspection Of the test area to determine if any
seeds were already on the ground.. In all tests, the
amount of seed on the ground prior to the harvest oper-
ation was negligible.

When checking for the pulling and raking losses,
the pulling and raking losses were combined since por—
tions of the raking Operation were performed simul-
taneously with the pulling Operation. A separation of.

these two types Of losses was.of no consequence to

61

later comparisons to be made with tests of the direct-
harvesting mechanism.

A predetermined plot three feet long and equi-
valent to the width of the number of rows included in
the final windrow was staked off after the windrow had
been completed and was ready for combining.

All loose seeds and pods were collected from the
plot. The loss per acre was then determined by corre-
lating the number of seeds or pods found in the test
plot with a given number of seeds having a known weight.

Combine pick-up losses were then checked by first
placing a canvas behind and below the pick—up attachment.
The combine operator then moved the combine over the
test plot in a normal manner; and as the canvas dragged
under the combine and passed over the specific test area,
it was placed on the ground where it now covered any
seeds or pods not gathered by the pick—up attachment.

After the combine had passed over the canvas, the
canvas was removed and the seeds and pods left on the
ground under the canvas were again collected and counted
to determine the combine pick-up attachment loss.

Threshing and separating losses were not checked
at the rear of the combine because they had no direct
consequence to the comparison tests with the direct-

harvesting mechanism.

62

The total of pulling, raking or windrowing and
pick-up losses will hereinafter be defined as gathering
losses or those losses encountered in performing all
Operations necessary tO transfer the standing crOp into
or onto the combine platform or header.

In order to apply a more meaningful figure to the
losses checked, it was decided that the losses should be
reported as a percentage Of pre-harvest yield.

Since time did not allow the checking of pre—
harvest yield, an estimate of the pre-harvest yield was
acquired by securing the harvested yield known by the
farm operator and adding tO this the loss determinations
for the pulling, windrowing and pick-up operations. An
estimate of one-half bushel per.acre for threshing,
separating and cleaning losses was also added to include
all harvesting losses. The sum of harvested yield plus

harvesting losses was then defined as pre—harvest yield.

Results
Table 8 numerically lists the losses resulting from
conventional harvest methods.
Listed in the Appendix is pertinent data relating
to each conventional field Operation which would include
dates of pulling, windrowing and combining, Special

attachments used and general field and crop conditions.

63

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CONSIDERATIONS OF AND TEST PROCEDURE FOR

THE FIELD TESTS CONDUCTED

Considerations Of Test Procedure

 

The test procedure had as its main objectives:

1. The determination of grain losses resulting
from the cutting operation.

2. The determination of the amount and direction
of plant movement after severance.

3. The determination Of the amount of power re-
quired to sever and move the plant material
using a double-disk cutting mechanism.

A. The determination of the overall Operating
characteristics of a rotary cutting unit as
related to the condition of the plant and
stalk, the inclusion of soil and stones in
the plant material, the ability to save low-
hanging pods, the effect of soil and stones
on the cutting disks, and the effect of
operating the cutting disks to one side of
the row.

The first three objectives were reviewed as they

were affected by two main variables, which included:

6A

65

l. The effect of changes in ground speed and/or

rotational disk speed.

2. The effect Of the operating height of the

cutting disks with respect to the soil
surface.

It was most desirable that all other factors be
held constant which might affect the test results. This,
however, was not wholly possible due to weather condi-
tions which varied daily and soil surface irregularities
which affected the Operating height of the disk blades
with respect to the soil surface throughout the test
area.

An attempt was made during the test procedure to
take note of these uncontrollable variables in order that

the resultant test data would be more meaningful.

Test Procedure

The first three objectives of the testing program
were to determine: (1) gathering losses resulting from
cutting, (2) plant movement after cutting, and (3) the
power requirements for each cutting disk.

All three determinations were made during one
test run over a test plot which was one—row wide (30
inches) and usually twenty feet long. This particular

area provided a sampling of fifty square feet.

66

Certain variables were changed and noted when

moving from one twenty—foot plot to another.

Preliminary Testing
Preliminary laboratory testing included the deter-
mination of the general effect that notching of a disk

had on the cutting ability of the mechanism. The over-

all effect is noted in the "Construction" section.

Preliminary field testing included the determination
of ground speeds for various gear and throttle settings.
This was done by timing the unit as it was driven over

a known length of the field at different gear and throttle

settings.
Also, the tachometers were calibrated to provide

aaccurate determinations of the cutting disk drive shaft

Speed.
Initial operation of the unit indicated that as

DZLant material was cut, it was moved rearward and dis-

tI‘ibuted to the left over the faster rotating disk. This

Pfissulted in the plant material being deposited in front

<3f‘ the left rear tractor wheel. This condition was not

cOnducive to the establishment of reliable loss tests or

FDliant movement tests. It was also noted that plant

marterial had a tendency to catch on or wrap around the

I‘Crtating drive shaft.

67

Consequently, combination guard-stripper plates
were installed around the disk mounting flanges and lower
drive shafts to overcome the distribution and wrapping
problems.

The sheet metal stripper plates were initially con-
toured to a shape that would lift the plant material
slightly as it was propelled rearward. No appreciable
lifting could be produced, however, without plugging
occurring between the stripper plates. These plates are
illustrated in Figure 6.

Lifting wires were installed above and in front of
the edges of the cutting disks in an attempt to lift the
low hanging pods over the cutting edges. These lifters

did not prove to be of any benefit and were discarded.

Gathering Losses

 

The initial step in determining gathering losses
was to first clean a predetermined area of the field of
any grain which may have been left from previous tests on
adjoining rows.

After cleaning the test plot and determining the
ground speed, disk speed and Operating height for the
given test, the test unit was then Operated over the
specific plot.

Grain losses were then determined by counting all
the beans removed from the pods either by shattering or

cutting of the pods. The number Of beans lost was then

68

correlated with the area Of the test plot to provide the
number of beans lost per square foot.

To provide a more accurate estimate of the number
of beans per square foot equivalent to a given loss per
acre, a random sample Of beans was gathered from the
test plot, weighed and counted. The weight was then
correlated with the number of beans to provide an esti—
mate of the number Of beans per square foot that were
equivalent to one Bu/A.

For the test area, it was determined that 3.15
beans per square foot were equivalent to one Bu/A.

Direction and Amount of
Plant Movement

 

To check the ability of the cutting mechanism to
move plant material into or onto the platform or table
of a grain combine, the movement of the plant material
was checked by randomly selecting three individual
stalks in the section of row to be harvested. These
stalks were then identified with paint. Their initial
standing position in the row was also identified by
markers on the surface of the soil near the standing
stalks.

Upon completion Of the stalk identification, the
subject test row was cut. The severed plant material
was then inspected to locate the previously identified

stalks. Upon locating the specific plants, a measurement

69

was taken from the initial point of stalk placement indi-
cated on the soil surface to the final point of stalk
displacement. The distance between these two points
was then defined as stalk movement.

Rearward movement of the stalk was defined as
movement in a direction Opposite to the direction in
which the cutting unit was traveling. Forward movement
of the stalk was defined as movement in the same direction

as the machine was traveling.

Power Requirements

 

To apply some realistic figures to the amount of
power required for Operating the disks, a pressure gauge
was installed at each hydraulic motor inlet and tacho—
meters were installed on the shafts driven by the
cutting disk drive shafts.

The hydraulic motor output HP could then be calcu-
lated using the following relationship:

psi x RPM x .229 in.-lbs./psi
5252 x 12

 

Output HP =

The .229 in.-lbs./psi is the manufacturer's output
torque specification for operating pressures within the
range of pressures experienced.

Output HP would include that power required to
overcome mechanical friction of the shaft mountings,

friction resulting from the disks rotating at or below

70

the soil surface and power required to actually perform
the cutting Operation.

The operating pressures for the left—hand disk
and right-hand disk were found to be 70 psi and 60 psi
respectively, when the machine was Operating above the
soil surface under no load. This pressure was relatively
constant over the speed ranges encountered.

The working pressures were checked and noted dur-
ing each test run. An attempt was also made to check
the operating speed during each test to note whether it
decreased by any significant amount from the pre-test
reading. Due to the relatively low working pressures,
disk speeds remained fairly constant throughout each

test.

RESULTS AND DISCUSSION

Gathering Losses

 

Figure 8 represents the gathering losses expressed
in Bu/A and in per cent Of pre-harvest yield as they
were affected by the Operating height of the_cutting
disks above or below the surface of the soil.

The general shape of the curve indicates that
gathering losses decreased as the Operating height of
the cutting disks decreased or as the operating time of
the cutting disks at or below the surface of the soil
increased.

Although field losses were also affected by
moisture content of the seed and plant material, an
attempt was made to estimate moisture content and relate
its effect to gathering losses. It is interesting to
note that of eighteen tests conducted with resultant
gathering losses of l per cent of the pre-harvest yield
or less, eleven of these tests were at moisture contents
estimated to be at about 20 per cent.

Gathering losses with conventional methods in the
Mason, Michigan area for the 1967 season averaged out

to 8.79 per cent Of the pre-harvest yield. This 8.79

71

Gathering Losses, Bu/A

 

72

 

 

 

 

 

 

.A—
.2 r
O l 1 l i l l
o 10 20 30 no 50 60 70 80 90

Operating Time At or Below Surface, Per Cent

Figure 8.--Gathering Losses vs Operating Height

DJ

 

Gathering Losses,

Per Cent

73

per cent consisted of A.92 per cent pulling and windrow—
ing losses and 3.88 per cent combine pick—up losses.

A comparison of conventional gathering losses
with loss tests of the two-disk cutting unit indicated
that:

l. Thirty-one Of thirty—two tests (97 per cent)
conducted were superior to average gathering
losses for conventional methods.

2. Twenty-eight of thirty—two tests (87.5 per
cent) conducted were superior to average
pulling and windrowing losses for conven-
tional methods.

3. Twenty-five of thirty—two tests (78.2 per
cent) conducted were superior to the smallest
pulling and windrowing losses listed for con—
ventional methods.

For the four tests with losses in excess of A.92
per cent of pre—harvest yield, the approximate height
of the stubble above the soil surface was 1.6 inches.

Figures 9 and 10, respectively, represent gather-
ing losses as affected by the average stubble height and
stubble height as affected by the Operating time of the
cutting disks at or below the surface of the soil.

An examination of Figure 9 indicates that gather-
ing losses are comparable to conventional methods if

the stubble height is maintained at or below one and

7A

6.3A

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— fll _ _ fi .fi a L

 

 

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Inches

Stubble Height,

Figure 9.--Gathering Losses vs Stubble Height

Stubble Height, Inches

[\1

N\M

N\M

 

 

1 I i 1 I l I i J
0 10 20 30 A0 50 60 70 80 90 100

Operating Time At or Below Surface, Per Cent

Figure 10.——Stubble Height Vs Operating Height

76

one-half inches. It is noted that at stubble heights of
one-half-inch to three—fourths inches, gathering losses
can be maintained as low as 2.5 per cent of pre-harvest
yield.

Following the curve represented in Figure 10, one
can determine from the test data that the cutting disks
should be operated at or below the surface about 65
per cent of the time with the test unit constructed.

Figure 8 indicates that at this Operating height
gathering losses of 2.25 per cent of pre-harvest yield
could be expected. This figure would favorably compare
with the 8.79 per cent average gathering losses and
A.92 per cent average pulling and windrowing losses for
conventional methods.

In order to correlate the operating height of the
cutting disks with the Operational time at or below the
soil surface, the disk height was measured vertically
fronithe point of the "V" formed by the two disks to
the bottom of the gauge wheels. For the majority of
field tests conducted, the Operating heights were either
2 11/16 inches or 2 l/A inches. The average operating
time at or below the surface was 62 per cent for an
Operating height of 2 11/16 inches and 78 per cent for
an Operating height of 2 l/A inches.

It should also he mentioned that the majority of

the gathering losses encountered were not shattering

77

losses resulting from the bean pods being popped Open
but were, instead, caused by the lower pods being cut
Open by the two disks.

It is for this reason that when the disks were
just below the soil surface, the pods, although in con-
tact with the soil, were never touched by the cutting
disks.

It, thus, appears that if disk height can be
maintained at or just below the soil surface, a lifting
device to lift the low-hanging pods over the edges of
the cutting disks is not required and may, in fact,
result in more losses due to shattering.

Gathering losses may, however, be increased if it
is necessary to utilize a feeding device of some type to
move the severed plant material away from the cutting
disks and rearward into a combine table should the
cutting unit be mounted directly in front Of a combine

table.

Plant Movement

 

Since the direction and amount of plant movement
was affected both by the operating height of the cutting
’disks and by the Peripheral Speed/Ground Speed Ratio
of the cutting disks, Figure 11 represents the plant
movement as it is affected by these two variables. The
Peripheral Speed/Ground Speed Ratio is referred to as

the P/G Ratio.

Inches

Plant Movement,

I Forward
O

Rearward

78

J:

(I)

16-

 

I 1 I I
O 10 20 30 A0

Operating Time At

 

C) 0—11 Ave. P/G
A 11.1—1A Ave. P/G

E] 1A.l—20 Ave. P/G

XEJDG)

X 20.1- Ave. P/G

 

l I I I I 11
SO 6O 7O 8O 90 100

or Below Surface, Per Cent

Figure ll.-—Plant Movement vs. Operating Height

79

Effect Of OperatinggHeight

Figure 11 indicates that as the cutting disks were
Operated at or below the surface a greater percentage Of
the time, plant material was moved rearward a greater
distance.

The three top curves demonstrate that rearward
plant movement increased at a decreasing rate as the
Operating height was lowered.

For Average P/G Ratios of 11.1 — 1A, the rate of
change began to decrease at Operating heights where the
cutting disks were at or below the surface of the soil
50 - 60 per cent Of the time or more.

For Average P/G Ratios of lA.l - 20, the rate of
change began to decrease at Operating heights where the
cutting disks were at or below the surface Of the soil
A0 per cent of the time or more.

At Operational times of 65 per cent at or below
the soil surface, plant movement was about two inches
rearward for Average P/G Ratios from 11.1 - 1A and about
four and one-quarter inches for Average P/G Ratios from
lA.l - 20.

Effect of Peripheral Speed/
Ground Speed Ratio

Figure 11 also represents the effect of changes in
disk speeds with respect to ground speed. This figure
reveals that as the Average P/G Ratio increased, plant

material was moved rearward a greater distance.

8O

Characteristics of Plant
Movement

It was interesting to note that plant material, as
it was severed, tended to follow the lower, faster, un-
notched disk, resulting in plant deposits to the left of
the center of the cutting unit. This characteristic
may be acceptable if the unit were mounted on a combine
table but was not desirable for straight windrowing.

Combination guard-stripper plates were installed
to:

1. Distribute plant material in a straight row.

2. Prevent plant material from catching on the

unit frame or wrapping around the drive shaft.

The constricting position of the guard—stripper
Lilates tested did limit the rearward plant movement to
a certain extent .

It is likely that a differently shaped stripper
pleate, possibly, vertically mounted above and extending
Fulrallel to a radius of the cutting disk to a point near
thee outer rear edges of the cutting disks, may still
furuction to prevent wrapping, yet may allow more rear-
WaIVi plant movement.

As nearly as could be determined, the position of
the? severed plants was such that at higher P/G Ratios
the-‘main.stem was pointed downward and rearward. At

lower P/G Ratios the stem was pointed downward and

Slight ly forward .

81

Power Requirements

 

Figures l2, l3, and 1A represent the hydraulic
motor output HP required to drive the shaft and cutting
disks individually and in total.

The figures represent HP as it is affected by two
variables: (1) operating height at or below the surface
of the soil, and (2) Average Peripheral Speed/Ground
Speed Ratios.

Although the plotted data varied considerably, it
is apparent that the horsepower required increased as the
operating time at or below the soil surface increased and
as the Average P/G Ratio increased.

The data shown in Table 9 lists speed and HP of
the left-hand disk compared to the right-hand disk for
twenty-one field tests.

TABLE 9.--A comparison Of the speed and HP requirements of
the cutting disks.

 

 

Average HP AfiiéiiiegP Speed Ratio
Required Left/Right Left/Right
Left—hand
Disk .7805
1.91/1 1.53/1
Right-hand

Disk .AO85

 

Output HP, Right Motor

82

Q G 0—11 Ave. P/G

A A 11.1-1A Ave.P/G

El [3 lA.l—20 Ave.P/G
x x 20.1— Ave. P/G

 

 

A
5 r EIX x
u _ /
El El Q A
.3 -
A A
.2 — .A
.1 —-
I l I I l I I I I i

 

O 10 2O 30 A0 50 6O 7O

80 90 100

Operating Time At or Below Surface, Per Cent

Figure l2.--Output HP, Right Motor vs

Operating Height

Output HP, Left Motor

83 Q G 0-11 Ave. P/G

A A 11.1—1A Ave. P/G
El IZI lA.l—20 Ave. P/G

X X' 20.1- Ave. P/G

 

 

5 14.1-20
l_ \
o— EX X
.9—
B
.8—
E]
.7—
5 F
A Q A
.A—
IA
.3—
,2_.
.1—
I I I I I I I I L, i

 

 

O 10 2O 30 A0 50 60 7O 8O 90 100

Operating Time At or Below Surface, Per Cent

Figure l3.--Output HP, Left Motor vs Operating Height

Motor Output HP, Total

8A

O-ll Ave. P/G
11.1-1A Ave. P/G
lA.l-20 Ave. P/G El

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0 10 20 30 A0 50 6o 70 80 90 100

Operating Time At or Below Surface, Per Cent

Figure lA.--Output HP, Total vs Operating Height

85

This data indicates that the HP required was not
linearly related to disk-speed changes. For the parti-
cular test data, the differential in HP required by the
two disks is approximately prOportional to the speed
ratio (Left/Right)l'5.

The increased HP requirement at lower operating
heights was a result of the increased soil friction
existing between the cutting disks and soil.

In examining Figures 12, 13 and 1A, the approxi-
mate HP required for Operating at or below the surface
of the soil at least 65 per cent of the time with a
1A.l - 20 Peripheral Speed/Ground Speed Ratio was about
1.5 HP in total with about .95 HP required by the left-
hand disk and about .57 HP required by the right-hand
disk.

For all tests, the maximum HP required was 1.8A
in total with about 1.15 HP required by the left-hand.
disk and .69 HP required by the right—hand disk.

The change in the HP requirement as affected by
the Operating time at or below the surface of the soil is
given by Table 10 which was derived from graphical data

in Figures l2, l3 and 1A.

86

TABLE 10.-—Additional HP required as Operational time at
or below the surface is increased.

 

Left-Hand Right-Hand Both Disks

 

Peripheral Speed/ Disk Disk
Ground Speed Ratio HP/10% HP/10% HP/10%
Increase Increase Increase
11.1 - lA/l .15A .066 .220
h
lA.l — 20/1 .0A1 .038 .079 .

 

 

Operational Characteristics

Plant and Stalk Condition

With the particular unit tested, there was true
shear of the plant stalk with very little shredding or
tearing. It was noted that at Peripheral Speed/Ground
Speed Ratios of less than about 10/1 there was a tendency
for the plant to be pulled forward out of the ground be—
fore complete severance occurred. This condition pro-
moted plugging of the cutting unit.
Cleanliness of Severed
Plant Material

Due to the root being left in the ground, the con—
dition of the plant material was such that there was no
soil or stones included with the plant material. This
would, Of course, assist in lowering the pick percentage

and result in less wear on the harvesting machine.

87

Ability to Save Low—
Hanging Pods

 

 

As previously mentioned under "Gathering Losses,"
the Operation Of the cutting disks at or below the soil
surface resulted in the cutting disks moving under the
bean pods, even though these pods may have been in con-
tact with the soil surface. The majority of the losses
encountered with low-hanging pods was from the pods
being cut Open, as Opposed to being Opened from contact
with the flat surface of the cutting disk or unit frame.
Effect of Soil and Stones
on the Cutting Disks

The field in which the unit was tested was a rela-
tively clean field, although pebbles and stones as large
as two inches in diameter were occasionally encountered.
At no time during the field tests was the cutting unit
damaged after contacting stones of this size.

Due to the relatively small notch size on the
notched disk and the smoothness of the un-notched disk,
it was felt that the stones never had the Opportunity
to catch on the disks and lock up the cutting unit.

The condition Of the notch or trailing edge of the
notch did not seem to change during the relatively short
test period. In fact, Operation Of the cutting disks in
the soil may have maintained a sharp edge on the moving

parts.

 

88

If the unit should be developed for use in crops
where disk height does not necessarily have to be below
the surface, the possibility of damage from soil or
stones would be decreased.

Effect of Lateral Movement of
the Cutting Disks on Cutting

Ability

In order to more accurately determine the effective

 

 

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l _ .

cutting angle for a mechanism of this type, the cutting
operation was observed as the machine was moved from one
side of the row to the other.

It was noted that in moving down the right side of
the row, poor cutting characteristics were Observed as
the center of the unit approached a point about four
inches to the right of the row.

Poor cutting characteristics included over—running
of the plant itself, inability of the disks to move the
plant material rearward and plugging at the throat of
the unit.

In moving down the left side of the row, these
same characteristics were observed as the center Of the
unit approached a point about five and one-half inches
to the left of the row.

A calculation Of maximum effective cutting angle
would indicate that the left, smooth disk has a maximum

effective cutting angle of about 72 degrees while the right,

89

notched disk has a maximum effective cutting angle of
about 85 degrees.

This indicated that the notched disk had a wider
Operating range and larger maximum effective cutting

angle than the smooth disk.

 

SUMMARY AND CONCLUSIONS

A review of present edible bean harvesting methods
and a comparison of these methods to the procedures used
for harvesting similar crOps indicated that a direct-
harvesting method would increase the value of an edible
bean crop by reducing the harvesting time, labor re—
quirements and harvesting losses and by increasing crop
value.

Initial work in Michigan on a single-disk rotary
cutting mechanism prompted a study of the performance of
a double-disk cutting unit which would completely sever
the plant stalk.

Due to the requirements for a mechanism which would
be light in weight and have a flexible and versatile
drive system, hydraulic motors were chosen as the source
Of rotary power for this application. The advantages of
a hydraulic drive system were readily evident for this
type of application where it was desirable to increase
disk speed as ground speed was increased in order to
maintain a constant Peripheral Speed/Ground Speed Ratio.

The results Of the field tests indicated that:

90

91

Gathering losses were directly proportional

to Operating height and decreased as operating
height was lowered.

An operating height Of 2 1/2 inches to 2 5/8
inches should provide an Operating time of
about 65 per cent at or below the soil sur-
face.

At the above listed Operating heights, gather-
ing losses Of about 2.5 per cent of the pre-
harvest yield were experienced. This compared
with gathering losses Of about 8.8 per cent

of the pre—harvest yield for conventional
methods in the Mason, Michigan area.

Gathering losses resulting from shattering of
the pods were minimal.

Gathering losses may be somewhat higher than
the test results if it were required that a con-
veying device be mounted at the rear of the
disks to move plant material rearward onto a
combine table.

Rearward plant movement was proportional to
the Peripheral Speed/Ground Speed Ratio and

as this ratio increased, rearward plant move-
ment increased.

At the above listed Operating heights, rear-
ward plant movement of about two to four

inches was experienced with the unit equipped

92

with guard-stripper plates and Operated with

a Peripheral Speed/Ground Speed Ratio Of about
11/1 to 20/1.

The horsepower required to Operate the disks
was directly prOportional to the operating
height, so that as the Operating height was
lowered, the required horsepower increased.

At the above listed operating heights and
Peripheral Speed/Ground Speed Ratios of

lA.l/l - 20/1, the total power required to

drive the disks' shafts was about 1.52 HP.

SUGGESTIONS FOR FURTHER STUDY

The following suggestions are provided to assist

in the direction of any further sfudies which might re-

late to a double-disk cutting mechanism.

1.

Laboratory research into the optimum cutting
notch size, shape and speed which most
effectively severs a given size stalk appears
to be pertinent to the design Of such a unit.
Laboratory research regarding the minimum»
disk size that will Operate effectively is
necessary if row widths decrease below 26
inches.

A more thorough investigation of the effect
disk speed changes with respect to each other
will have on the cutting action is important
to achieve the most effective cutting action.
Due to the critical effect of operating height
on gathering losses, the development of a
mechanism to automatically control the Oper-
ating height of the cutting disks appears to
be especially important when operating in
crOps which have the grain located close to

the soil surface.

93

9A

The operational characteristics of a double-
disk cutting unit mounted on the front of a
combine and equipped with a conveying mechan-
ism to move plant material rearward appears
to be a necessary step in the adoption pro-
cedure for a direct-harvesting machine. A
line drawing of the cutting units mounted on
a combine table can be found in Figure.l5.

A field study Of the effect Of various plant
maturity levels, plant varieties, and plant
spacings on the overall operation of the unit
may provide additional information regarding
the acceptability of the unit for varying
plant conditions.

An economic study of the reduced costs and
increased returns, if any, of direct-harvest-
ing with a unit Of this type compared to con-
ventional methods will be necessary before a
meaningful decision can be made regarding the

acceptability of the unit.

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REFERENCES

96

10.

REFERENCES

Anstee, L. L. (1962). The development of a belt puller
harvesting attachment for direct-combining Of edible.
beans. Thesis for the degree of M.S., Cornell Uni—
versity, New York.

Asher, J. (1951). The adaptation Of the combine to ”I
the harvesting of navy beans., Thesis for the degree
of M. 8., Michigan State University, East Lansing.
(Unpublished).

 

Conlin, Edward (1967). USASI standards. "Hydraulics
and Pneumatics." Vol. 20, Nos. 3, 5 and 7. pp. 90—97.

Cooperative Extension Service, Michigan State University
(1965). Field Bean Production in Michigan. East
Lansing, 10 pp.

Csorha, J. J., and J. W. Kirkbride (196A). Harvesting
of Corn, Small Grains and Related Crops. United States
Department of Agriculture, Economic Research Service,
Washington, D. C. 53 pp.

(1966). Farm tractor and machinery hydraulics
series. "Implement and Tractor." Vol. 81, Nos. 2—7.

Gay, L. H., and M. E. Long (1966). Remote hydraulic
motors. "Machine Design." Vol. 38, NO. 28, pp. 118-
121.

Gunkel, W. W., and L. L. Anstee (1962). Direct-harvest—
ing of dry beans. Agricultural Engineering, A3:69A-
697, 716.

Khan, A. U. (1952). Efficiency of harvesting navy
beans with a combine. Thesis for the degree of M.S.,
Michigan State University, East Lansing. (Unpublished).

McColly, H. F. (1958). Harvesting edible beans in
Michigan. Transactions of the ASAE, l:(l)68-7l, 75.

97

ll.

l2.

13.

1A.

15.

98

Pippenger, J., and T. G. Hicks (1962). Industrial
Hydraulics. McGraw-Hill, Inc., New York. 35A pp.

 

 

United States Department of Agriculture (196A).
Labor used to produce field crops. USDA Economic
Research Service, Washington, D. C., A3 pp.

United States Department of Agriculture (1966).
Agricultural Statistics. USDA, Washington, D. C.

United States Department of Agriculture (1966).
Field CrOps by States,Yield and Production (1959-
196A). USDA Statistical Reporting Service, Washing—
ton, D. C., 90 pp.

Zimmerman, M. (1966). How much hydraulic horsepower?
"Implement and Tractor." Vol. 81, No. 11, pp. 15—17.

APPENDIX

99

100

RELATIVE INFORMATION ON FIELD TESTS CONCERNED

WITH CONVENTIONAL HARVESTING METHODS

Operation A
Three field trips
1. Pull and rake, September 5

2. Rake, September 6 and 7
3. Combine, September 8
Equipment used
1. 2-Row, tractor-mounted, hydraulically-adjustable
2. Parallel-bar rake

3. Special bean combine with edible bean pick-up

attachment

Operation B

Three field trips
1. Pull and rake, September 8 and 9
2. Rake, September 10
3. Combine, September 11

Equipment used
See Operation A

This particular Operation was performed in beans which

.had.been damaged by hail and was not considered as being

indicative of a normal crop.

101

Operation C

Three field trips
1. Pull and windrow, September 1A
2. Rake, September 1A
3. Combine, September lA

Equipment used
1. A—Row, tractor-mounted, manually—adjustable
2. Edible bean windrower
3. Parallel-bar rake
A. Regular grain combine with spike-tooth cylinder

and edible bean pick-up attachment

Operation D
Three field trips
1. Pull and rake, September 18
2. Rake, September 18
3. Combine, September 18
Equipment used

See Operation A

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