\WI’NMI W» U ‘| W k — — —'" —4 — :— W H s \|‘ (13—301 MECHANICAL CUCUMBER HARVESTENG Thesis {or the Degree of M. S. MICHIGAN STATE UNIVERSITY Ronald Keith Leonard i958 THESI C -l MECHANICAL CUCUMBER HARVESTING By Ronald Keith Leonard AN ABSTRACT Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Agricultural Engineering 1958 gag/M Approved ii Michigan ranks first in the United States in the production of pickling cucumbers. Because of the expense and uncertainty of the transient labor used to harvest this crop, a suitable harvesting machine is desired by the Michigan farmer. The purpose of this thesis is to set forth (1) basic data gathered concerning the physical preperties of the cucumber vines and fruit, (2) the design and development of a pneumatic vine trainer and (3) the invention, design and development of a new mechanical cucumber harvester. The review of literature revealed in a general man- ner some of the physical characteristics of the cucumber which must be considered in the develcpment of a mechanical harvester. It traced the brief history of harvesting mech- anization to the beginning of this investigation. The study of the problem of providing a commercially acceptable cucumber harvester logically divides into three phases as follows: (1) Physical Properties of Selected Varieties of Pickling Cucumbers, (2) Vine Training for Mech- anical Harvesting and (3) Mechanical Cucumber Harvester. Data were taken on three days during the harvest season to determine the effect of time of day, location of the fruit on the vine and the size of cucumber on the pick- ing force. It was found that the picking force varied significantly only with the size of cucumber. The picking forces for several varieties were Ronald Keith Leonard iii measured. It was found that Wisconsin SHE-12 required the 'least picking force of the varieties tested. The strength of the leaves was measured and found to be stronger than required for the vacuum pickup unit used on the mechanical harvester. The specific weight, the specific gravity and the weight-size relationship of the fruit were determined. Measurement data were taken to record the geometric size and configuration of the vines, leaves and fruit. To facilitate the development of mechanical cucum- ber harvesters which operate from one side of the row, a pneumatic vine trainer was develOped which trained the vines to grow perpendicular to the row center. Data were recorded to measure its effectiveness for training the vines and to ' evaluate its effect upon the fruit set in the root zone. A mechanical cucumber harvester was invented, designed and constructed which utilized two new principles, ‘A‘g. a vacuum pickup and elevating unit and a cleated belt picking bed. This machine was developed so that it func- tioned satisfactorily under typical field conditions. It was found that a negative static pressure of 10 inches of water acting over an effective hole area in the belt of #2 square inches was required to pick up and elevate the vines. The picking bed functioned in a satisfactory manner but no picking efficiency data were obtained. Afionald Keith Leonard MECHANICAL CUCUMBER HARVESTING By Ronald Keith Leonard A THESIS Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Agricultural Engineering 1958 IIJ7’5I' cr'W/7 ACKNOWLEDGEMENTS The author wishes to express his sincere apprecia- tion to all who have contributed to this investigation. The contributions of the following are especially recognized: Doctor W. F. Buchele, Adviser, for his inspiring guidance throughout the entire investigation. Doctor M. L. Esmay, Doctor w. B. Baten and Professor H. F. McColly, the other members of the guidance committee, for their many helpful suggestions. Doctor A. w. Farrall for arranging the assistantship and providing the personnel and facilities for graduate study. The National Pickle Packers Association for the research grant that made this work possible and the John Deere Des Moines Works of Des Moines, Iowa, for granting the author a one-year leave of absence and for donating material used in the construction of the machine. Messrs B. A. Stout, G. W. Bingley and M. Beckwith for their COOperation and assistance with the construction and testing of the machines. Elizabeth, my wife, for her faith and support, and for assistance in preparing and typing the manuscript. TABLE OF CONTENTS INTRODUCTION . - . . . . . . e . . REVIEW OF LITERATURE . . . . . . . INVESTIGATION . . . . . . . . . . Physical PrOperties of Selected Varieties of Pickling Cucumbers . . . . Objectives . . . . . . . Procedure . . . . . . . Picking forces . . Strength of leaves Specific weight, specific gravity weight-size relationship Geometric size and configuration of vine, leaves and fruit Results and discussion . Picking forces . . Strength of leaves Specific weight, specific gravity weight-size relationship Geometric size and configuration of vine, leaves and fruit Vine Training for Mechanical Harvesting . . Objectives . . . . . . . Procedure . . . . . . . Results and discussion . \} OVVV 10 10 12 12 12 18 18 19 2A 2A 25 27 TABLE OF CONTENTS, Continued Mechanical Cucumber Harvester . . . . . . . . . Objectives . . . . . . . . . . . . . . . . Design and construction of the machine . . Pickup unit . . . . . . . . . . . . . Picking bed . . . . . . . . . . . . . Fan and ducts . . . . . . . . . . . . Power application . . . . . . . . . . Main frame and mounting on tractor . Test procedure . . . . . . . . . . . . . . Vacuum pickup and elevating unit . . Flight elevator picking bed . . . . . Results and discussion . . . . . . . . . . Static pressure determination . . . . Final Operating speeds of machine elements 0 O O O O O O O O O O O O Tensile forces in vine due to picking action . . . . . . . . . . . . . . Description of machine performance . CONCLUSIONS .................... SUGGESTIONS FOR FURTHER STUDY . . . . . . . . . . . REFERENCES.................. Page 31 31 31 32 36 37 37 39 I41 1&2 1m 1&6 1+6 '49 1+9 51 55 57 58 LIST OF TABLES Table Page 1 Studentized range test of average picking force (gms) for Size I, II and III SMR-lz cu- cumbers at first picking. . . . . . . . . . . 13 2 Average picking force and weight for three harvest dates of SMR—lz cucumbers . . . . . . l6 3 Picking forces and weights for ten varieties of pickling cucumbers . . . . . . . . . . . . 17 A Effect of pneumatic vine trainer on #8 day old vines 20 to 2b inches long . . . . . . . 28 5 Natural growth of untrained vines planted in flat north-south rows . . . . . . . . . . . . 29 6 Effect of pneumatic vine trainer on number of fruit set in the root zone . . . . . . . . . 30 7 Tensile forces in vine due to action of the cleats on the picking bed . . . . . . . . . . 50 8 Vine damage and machine capacity . . . . . . 51 Figure N \J O\U\ 3h) 10 11 12 13 1H 15 16 17 18 LIST OF FIGURES Spring scale used to measure picking force . . Cucumber vine. . . . . . . . . . . . . . . . . Apparatus used to determine leaf strength . . Picking force vs. weight of SMR-lz variety . . Weight-diameter relationship of SMR-lz variety Weight-length relationship of SMR-lz variety . Pneumatic vine trainer mounted on IHC Model 230 tractor . . . . . ... . . . . . . . . . . Pneumatic vine trainer in action mounted on Allis-Chalmers Model G tractor . . . . . . . . Overall view of the mechanical cucumber harvester O O O O O O O O O O O O O O O O O 0 Side view of vacuum pickup unit. . . . . . . . View of the picking bed . . . . . . . . . . . Cleated belt picking principle . . . . . . . . Rear view of harvester showing fan and ducts, main frame along right side and main drive shaft directly under main frame . . . . . . . Drive connections to tractor . . . . . . . . . Picking bed lift linkage . . . . . . . . . . . U-tube manometer used for static pressure measurements . . . . . . . . . . . . . . . . . Vine support rod located on picking bed. . . . View showing the author and Dr. Buchele measur- ing vine tensile forces due to picking action or the Cleats O O O O O O O O O O O O O O O O O Page 11 15 21 26 26 33 35 35 36 38 no no “3 “3 Figure 19 20 21 22 23 2“ Negative static pressure vs. belt hole area . Negative static pressure vs. engine rpm . . . Front view of harvester approaching vines. . . Vines passing through machine. . . . . . . . . Top view of vines falling off rear of picking bed 0 O O O O O O O O O O O O O O O O O O O 0 Condition of vines after harvester has passed. Page 47 #8 52 52 53 53 INTRODUCTION Michigan ranks first in the production of pickling cucumbers, growing nearly one-fourth of the cucumbers raised for pickles in the United States. Ries (1958) states that uo,ooo acres yielded an average of 111 bu per acre during the years 1955 to 1957 and was worth about five million dollars a year to the Michigan farmers. Migrant labor for growing and harvesting this crop is now imported from the Southern United States and Mexico. The cost of harvest labor alone is equal to one-half the total value of the crop. Because of the expense and uncertainty of the tran- sient labor used to harvest this crop and the physical exertion necessary to harvest cucumbers by hand, a suitable harvesting machine is desired by the Michigan farmer. Members of the National Pickle Packers Association have encouraged every possible means to hasten the develop- ment of a mechanical cucumber harvester. Consequently, a cOOperative research project was established at Michigan State University to further the development of such a har- vester. This project is under the direction of Dr. W. F. Buchele and Mr. B. A. Stout of the Agricultural Engineering Department and Dr. S. K. Ries of the Horticulture Depart- ment. During the summer of 1957, four machines (the only 2 completely mechanical cucumber harvesters known to the National Pickle Packers Association) were furnished to Michigan State University by the Association to be used in any manner that would further the development of a commer- cially acceptable harvester. Since the author was not present for the 1957 field tests of these machines, he drew heavily upon the knowledge gained to form the basis for this study. Stout (1958a) reported that the overall picking efficiency of these machines was less than 50 per cent. The harvesters varied (l) in their ability to pick up the cucumber vines, (2) in the amount of damage to the vines, fruit and leaves, and (3) in their ability to separate the cu- cumber fruit from the vines. Because of low picking effi- ciency and damage to vines and fruit, research into new mechanical devices for performing the functional require- ments of a mechanical cucumber harvester was considered necessary to expedite the develOpment of a commercially acceptable machine. The purpose of this thesis is (l) to set forth basic data gathered concerning the physical properties of the cucumber vine and fruit, (2) the design and development of a pneumatic vine trainer and (3) the invention, design and development of a new mechanical cucumber harvester. REVIEW OF LITERATURE The literature review revealed few references deal- ing explicitly with mechanical cucumber harvesting. A reference source, compiled by Banadyga (19“9). applied in a general manner to the entire field of pickling cucumber production. In discussing hand harvesting of cucumbers, Banadyga pointed out five factors which are also pertinent to mechanical harvesting. They were as follows: (l) Hand harvesting cucumbers for pickling is regarded as the larg- est expense in growing the crOp; this expense is governed by the number of pickings. (2) Michigan research workers have shown that the total number of fruit set increases with more frequent pickings, but the total weight of fruit was greatest when there were longer intervals between pick- ings. (3) Studies of picking frequency ranging from one to seven days showed that financial returns to the farmer were greatest for the four day interval. (A) Many pickle packers pay a premium for small pickles. (5) Cucumber vines are easily injured during hand picking. In a report on pickling cucumber varieties for Michigan,.Peterson and Ries (1958) stated: 0n the basis of four years' results, it appears that the most widely acceptable variety is Visconsin SHE-12 . . . . . Its principal defects are: (1) lack' of firmness as measured by pressure test . . . . t In this same report the L/w (Length/Width) ratio for SMR-lz was 2.8 for cucumbers grown in Ingham County in 1955 and was 2.6 in 1956 and 1957. The ratio generally preferred by Michigan packers is approximately 2.6:1 with an acceptable range of 2.5:1 to 2.8:1. The pressure test referred to in this report was conducted with the standard fruit pressure tester with a five-sixteenth-inch tip. A pressure reading of 1n psi or higher is desirable. In a report on mechanical cucumber harvesting, Allard (1956) discussed several physical characteristics of the cucumber vine and fruit which might affect mechanical harvesting. He noted that the cucumber was much heavier than an equal volume of vines and leaves and that the cucum- bers hang down beneath the vine when the vine is held taut by lifting the end off the ground. He also observed that the size of the plants increased and the vines became brittle as the harvesting season progressed. For hand harvesting cucumbers, Beattie (1930, l9h2) stated that the cucumbers should be planted in rows 6 to 7 feet apart. He observed that each plant branches profusely and forms from 15 to 25 lateral branches. Dependent upon the growing conditions, Beattie felt that pickling cucumbers should be harvested at intervals of l to 3 days. _ Ries (1958) reported that the fruit should not be allowed to mature on the vine because mature cucumbers hinder the deve10pment of new fruit. In a report concern- ing the economics of irrigating pickling cucumbers, Hoglund 5 (1958) cited a significant increase in production with a proper combination of fertilizers, irrigation and manage- ment. This indicated that future levels of production may be higher; hence, the current harvesting conditions could soon undergo considerable change. Hall and MacGillivray (1956) reported that a hh-foot wide field conveyor (designed to transport the hand harves- ted cucumbers to the center of the machine) tripled the hand harvesting rate. ' George (1955) indicated that a human carrier for harvesting vegetable crops reduced the harvest time for cucumbers 15 per cent.~ Chisholm (1955) described the deve10pment of a mechanical cucumber harvester invented by Gilbertl. This machine will replace no harvest hands and harvest 1 to 1% acres per hour. In a report entitled ”Mechanical Cucumber Harvester Operation of 1955”, Borsenik (1955) furnished data concern- ing the Crew cucumber harvesterz. Borsenik found that when compared with the total number of cucumbers in the field, 5h.8 per cent were picked in a saleable condition and that the machine Operated at the rate of five-sights acre per hour. At the inception of this investigation four machines lus PATENT NO. 2,829,48u. 205 PATENT NO. 2,8hl,9h7. 6 designed to harvest cucumbers were undergoing preliminary field testing at Michigan State University under a cooper- ative agreement with the National Pickle Packers Association. Stout (1958a) described these machines. They included the Gilbert and Grew machines mentioned above, another machine invented by Grew, and the Craig machine. He reported that for the limited amount of data collected, the overall efficiency of these machines was less than 50 per cent. Stout reported on two problems which limit success- ful mechanical harvesting with existing machines. These are (1) vine damage and (2) the inability to harvest the cucumbers growing within 6 to 8 inches of the row center. In a later paper Stout (1958b) reported that after several modifications of these machines, the above problems still existed. The review of literature has suggested in a general manner several of the physical characteristics of the cucum- ber which must be considered in the deve10pment of a mechan- ical cucumber harvester. It traced the brief history of harvesting mechanization to the beginning of this investi- gation. INVESTIGATION This research endeavor logically divides into three distinct phases and is presented accordingly. Physical Properties of Selected Varieties of Pickling Cucumbers The importance of using basic physical data concern- ing agricultural cr0ps in the solution of mechanization problems is slowly gaining recognition. The topics presented herein were considered to be of fundamental interest to the design and development of mechanical cucumber harvesting equipment. W The objectives were to provide physical and design data concerning the cucumber vine and fruit. These data will include the following items: (1) picking forces, (2) strength of the cucumber leaves, (3) Specific weight, specific gravity and weight-size relationship of the cucum— ber fruit and (h) geometric size and configuration cf the vine, leaves and fruit. W Wisconsin SMR-12 was selected as the variety to be used for all of the physical preperty studies. As indi- cated in the Review of Literature, it is ”the most widely 8 acceptable variety” in Michigan. gigkigg_§gzgg§‘ — The force necessary to separate the cucumber from the vine was measured in the field with the spring scale shown in Figure l. A maximum st0p indi- cator was attached to the indicating scale to record the maximum value of the shearing force. The spring scale was calibrated by using a set of standard weights. The procedure for conducting the picking force tests was standardized as follows: The cucumber was held firmly against the ground; the spring-scale hook was placed around the stem adjacent to the cucumber. The scale was pulled slowly perpendicular to the axis of the cucumber and stem until the stem separated from the cucumber. The max- imum value of the shearing force was recorded. The picking force study was divided into two parts. _First, a three-way classification statistical design was used to determine the effect of time of day, location of the fruit on the vine and the size of the cucumber on the pick- ing force. Data were collected for three periods during the day, 8:30 to 9:00 a.m., 1:30 to 2:00 p.m. and #:00 to #:30 p.m. The positions on the vine were classified in two ways: Position 1 - 0 to 6 inches from the root, and Posi- tion 2 - beyond 6 inches. The sizes were divided according to H. W. Madison Company grades - number ones (size I), number twos (size 11) and number threes (size III). As each sample was taken, the weight of the cucum- ber was also recorded. These data were collected in a Figure 1. Spring scale used to measure picking force. Figure 2. Cucumber vine. Note the leaves and flowers or cucumbers at each node. 10 small plot of variety SMR-12, planted June 3 and located on the Michigan State University Horticulture Farm, for the first, third and fifth pickings. The data were obtained for the third and fifth pickings to check the effect of growing season on the picking forces. The second part of the picking force study was to determine picking forces for several varieties of cucumbers grown on the Horticulture Farm. The procedure for securing the picking forces was the same as described above. For these data only picking forces and weight were recorded for each variety. A figggngth_g£_lggygsg - The strength of the cucumber leaves was determined by placing the leaves over an orifice and then subjecting the leaf to a measured head of water (Figure 3). When the leaf failed the maximum head was recorded. Orifice plates containing l/h, 1/2 and 3/h-inch diameter orifices were fastened in turn to the end of a pipe. Heavy grease was applied to the orifice plate before placing the leaf over the orifice. This was done to pre- vent water from leaking under the edges of the leaf and out of the orifices. After placing the leaf over the orifice and fastening the orifice plate to the pipe, the pipe was filled with water. A glass tube was fastened alongside the pipe and was used to determine the maximum height of the water column. w f it - .zglgpignfinip‘, - For measuring the specific weight of the 11 --~GLASS TUBE 1%} I TOTAL HEAD= h.+h ” PIPE ——x we? LEA F—x ~ ORIFICE \- ORIFICE PLATE FIGURE 3. APPARATUS USED TO DETER- MINE LEAF STRENGTH 12 cucumber the water displacement method was used to determine the volume of the cucumber. Before submerging the cucumber in the water, it was weighed on a gram balance scale. Grad- uate cylinders of 100, 500 and 2000 ml capacity were used depending upon the diameter of the cucumber. Since for water, 1 ml 9’1 cc, by dividing the weight in'grams by the volume in cc, the specific weight of the cucumber was obtained directly. In metric units this is also equal to the specific gravity. As each of these measurements were taken, the length and diameter of the cucumbers were also recorded. This information and the weight of the cucumber were analyzed to establish the mathematical relationship which was discovered between the weight and length and the weight and diameter of the cucumber. WWW snfi_fxni§. - To observe the growth characteristics of the vine, limited data were collected indicating the number, size and spacing of laterals at various stages of the vine growth. Also, the height of the leaves above the main stem, area of the leaves, diameter of the main stem and length of vine were recorded. The length, diameter and weight of the fruit were recorded for the specific weight determina- tion. WW 21931gg_fgng§s. - An analysis of variance of the picking'force data showed that the size of cucumber affected 13 the picking force significantly at the 5 per cent level. The Studentized Range Test1 of the picking force averages for the three sizes indicated that a significant difference existed only between the average of Size I and the average of Size III cucumbers. Table l portrays these results. TABLE I STUDENTIZED RANGE TESTa or AVERAGE PICKING FORCE (gms) FOR SIZE 1, II, AND III sun-12 CUCUMBERS AT FIRST PICKING 864 1171 lhué .1 . I, ,1 L I *1 l 800 1000 1200 iuoo 1600 aLines joining any two numbers indicate no signifi- cant difference. . Position on the vine and time of day did not affect the picking force significantly, therefore, only force and weight were recorded during the third and fifth pickings. Since force and weight had been recorded for each sample, it was possible to perform an analysis of covariance of the data. This analysis Of the first picking data showed that, when all of the data were adjusted to the same weight Of pickle to eliminate the effect Of size, there was no sig- nificant difference in the picking force. This supports the previous analysis that picking force is dependent upon * 1David B. Duncan, ”Multiple Range and Multiple F Tests," Bipngtzigs, Vol. II, No. 1 (March, 1955), 1-u2. 1h size. To establish the relationship between picking force and size or weight, the data for all three pickings were analyzed separately. Regression equations of the form F 8 a + bw * SE where u: (I Picking force in grams a a F-intercept b s SlOpe Of the line H weight in grams SE a Standard error were calculated for each set of data and are plotted in Figure A. These equations for the first picking on July 31, 1958, third picking on August 7. 1958, and fifth picking on August 15, 1958, respectively, are as follows: F a 902 + 3.55v * #10 (1) r - 1002 + 2.72w * 387 '(2) r = 1107 + 2.05w s #72 (3) Equations (1). (2) and (3) were tested for signifi- cance. The "t" tests for the slopes of the line at the 5 per cent level indicated no significant difference between any Of the slopes: the ‘t' tests for the F-intercepts showed a significant difference between the F-intercepts of equa- tions (1) and (3). It should be noted that (for the three dates) the SlOpes were decreasing while the F-intercepts 15 r ZOOOT IOOO'r P=902+3.55w 57 DAY OLD VINES I44 SAMPLES c a: E g 2000+» (J , - 3 I000" - F=l002+2.72W @ 64 DAY OLD VINES § 78 SAMPLES _g 0 O. 2000* 1000-,- F=IIO7 + 2.05w 72 DAY OLD VINES 0 s2 SAMPLES 0 I60 200 360 WEIGHT,gr0ms FIGURE 4. PICKING FORCE vs WEIGHT OF SMR- l2 VARIETY 16 were increasing. The average picking force and weight for the three dates are shown in Table 2. TABLE 2 AVERAGE PICKING FORCE AND WEIGHT FOR THREE HARVEST DATES OF SHE-12 CUCUNBERS W Date Force Weight 1958 gms gms July 31 1162 72.8 August 7 12h5 89.5 August 15 1369 128.0 The results of the picking forces Obtained from ten different varieties Of cucumbers grown on the Michigan State University Horticulture Farm are shown in Table 3 for two different dates. These data were adjusted to the same weight by using the mathematical relationships (1), (2) and (3) Obtained for the.SMR-12 variety. It was assumed that these relationships held for all varieties. The only justi- fication for this assumption is simply that this is the only variety for which such a relationship has been Obtained; however, the author feels that similar relationships can be found for all varieties. Table 3 indicated that there was a difference in adjusted picking force between SHE-12 and the rest Of the 1? .mOapoaam> Ham mom made» one: Amv can Amv .Aav macavmsoo wSaESmmm encamppo one: one manpasoso anew ooa pom can monam>n .onmspnmdon casuasoapaom on» no nonsense .aa one meam .AQ an nonmasaamm Ill omaa mm mama moma mm mama mm edeez mama mm mmma omsa mm mmma msaxmma eaensm mm: omma maa mmma onaa ma omma mmmaxmom easasm.mma coma mm mmea cama mm mnsa mmmzxmam easasm mm: omma an aama mama mm amea smaa .ma xeeam .so omma mm emma mama mm mmma maumzm saasoeeas omea mm emea omma me mmma nmma ease «ma .oz em: mama an mmua onaa mm mama maxm seesanom mama as eosa mama as oaaa. maumzm saesoeeaz omma ma amaa omaa an eom «a-mzm saesoeeaz new new new new new new coach unmamz coach ooaom mamas: coach Oopmsnc< owmao>< oMmao>< nwWszaO< owmao>< ommao>< whamdhm> mmma amw seemsm mmma .am sass mmmmZDODo czHAMon m0 mMHBmHm<> zms mom mBmGHmS 92¢ mmomom czHaon n mum MSaasmmos mamnosm .ma com aonpsm one waa303m sma> .ma osswam . A O ‘ ‘B . '5 . o I. O h0’Wz'h ‘v\'ulfi. :. .“ . .‘ 4 C 4‘ s I. 40 . . ‘U- I foeifll‘vai. A! our. 6 .. p a ..... ‘11:... .m- . '. #6 The capacity of the machine was then calculated by using the length of the plot, the time consumed for the machine to harvest this plot and a 6-foot row spacing. Wm The entire machine described in this thesis was develOped to operate satisfactorily. Because most of the harvest season was required for this developmental work, little time was available at the end of the season for test- ing the performance of the machine; however, data which were collected in the process of deve10ping the machine will be set forth. The results presented include the following tepics: (1) static pressure determinations, (2) final oper- ating rpms and velocities of the machine elements, (3) tensile forces in the vine due to the picking action of the cleats on the picking bed, (A) vine damage and machine capac- ity and (5) description of the machine operation. SLaLAg_nngfifiuz§_dgtggm1na§19ns. - Figure 19 indicates that the minimum negative static pressure occurred in the vacuum chamber (at 2000 rpm, maximum engine speed) with the maximum effective hole area of 85 square inches in the belt. Figure 20 shows the relation of the negative static pressure to the tractor engine rpm. Field tests indicated that 10 inches of negative static pressure was required to elevate the vines as the machine moved down the row. This pressure was obtéined by covering half the hole area with masking tape as shown in Figure 21. The effective width of the pickup belt was then approximately 2h inches. a? 20V . l/2'INCH DIAMETER HOLES . NEGATIVE STATIC PRESSURE inches of wc fer O 20 4O 60 80 IOO EFFECTIVE HOLE AREA square inches FIGURE I9. NEGATIVE STATIC PRESSURE VS BELT HOLE AREA - as '2... _ .I. m IO c: :3 a) a) 3+- “J .. FAN INLET 85 s O Q 3 _ 61. '3 .— I— o m :4) Lu 0 4+ ->- is '2 .. c9 2-- ”“21 ,. VACUUM ' CHAMBER c O 550 IO:OO ISJOO 2:00 TRACTOR ENGINE RPM FIGURE 20. NEGATIVE STATIC PRESSURE VS ENGINE RPM “9 i f em . - The rpm or velocity of the machine elements at the end of the development phase are as follows: 1. Tractor engine - 2000 rpm Fan - 3&00 rpm Main drive shaft - 272 rpm Picking bed - 3&4 rpm Pickup belt - 86 rpm Pickup roller, 5-1/4 inch diameter - 23h rpm Pickup roller, 1-3/4 inch diameter - 602 rpm Linear velocity of pickup belt - 71 fpm O \OCDVOUCUN 0 Linear velocity of picking bed cleats - 338 fpm WWW.- Without the vine support rod (Figure 17), the picking action of the cleats on the picking bed pulled the vine out of the ground. This rod was positioned 10 inches above the ground and parallel to the top edge of the cleats. With the rod in this position, the tensile forces were then measured. Table 7 indicates the results of these force measurements. The maximum force of 2.5 lbs occurred at the greatest linear velocity of the cleats. With the rod located in this posi- tion, no vines were torn from the ground because of the action of the cleats tugging on the vines. The results of the data collected to measure vine damage and machine capacity are set forth in Table 8. The results in Table 8 are not conclusive and are presented be- cause they indicate the manner in which the performance of 50 the machine can be measured and can serve as a basis for comparing future work done with the machine. The vines from which these data were obtained were a late planting on the Horticulture Farm. Although the vines had a nice, lush appearance, they were producing few fruit. TABLE 7 TENSILE FORCES IN VINE DUE TO ACTION OF THE CLEATS ON THE PICKING BED W Linear Velocity Vine Vine of Cleats on Tensile Lengths Weight Picking Bed Forces inchsg‘ lbs fpm lbs 59 1.2 298 1.8 #8 1.0 298 -O.5 55 1.5 298 1.5 59 1.2 338 2.3 36 0.8 338 1.0 62 2.0 338 2.6 60 1.0 338 0.8 A6 1.1 338 2.3 In later work conducted at Dansville, Michigan, on large, mature vines, estimated machine capacities of two to three times those set forth in Table 8 were obtained. 51 TABLE 8 VINE DAMAGEa AND MACHINE CAPACITY Rate Total weight Weight orb Length of of material Material Vine Machine of row Time Travel handled Removed Damage Capacity ft min mi/hr lbs lbs per cent A/hr 7O 2 O.HO 42 O.h8 1.1 0.29 81 2 0.h6 30 0.52 1.7 0.33 8Expressed as per cent of weight removed. bDoes not include weight of cucumbers removed. We. - The entire machine functioned satisfactorily at the conclusion of the developmental work. Figures 21, 22, 23 and 2h show a se- quence of operations of the machine. Significant features of the performance of the machine are as follows: (1) The vacuum pickup unit lifted the vines without damage by grasping the leaves and ele- vated them onto the picking bed. Due to this lifting and elevating action, the cucumbers hung down below the vine. (2) The picking action of the cleats on the picking bed re- moved all commercial sizes of cucumbers from the vine. (3) Vine damage caused by the picking action of the cleats was 'less than 2 per cent (Table 7). (h) The vines moved across the bed perpendicular to the row center. (5) The vines fell from the bed so that they remained perpendicular to the row. Figure 21. Front view of harvester approaching vines. Note pickup lift hanger and cable. Figure 22. Vines passing through machine. Figure 23. Top view of vines falling off rear of picking bed. Figure 2A. Condition of vines after harvester has passed. Notice vine is perpendicular to the row and is not damaged. 5h It must be remembered that these results are based upon the limited amount of testing which was conducted after the machine was deve10ped until it performed satisfactorily in the field. The following factors hampered field operations of the machine: (1) To obtain the proper ground speed for the machine and still operate the fan at the maximum rpm, it was necessary to tow the entire unit with another tractor. This problem could be minimized by using a tractor with a live PTO which also has a wide range of forward travel speeds. (2) The pivot side of the picking bed was mounted too close to the ground causing interference with rocks and uneven ground profile. (3) Continuous operation of the fan was limited to less than #5 minutes because the V-belt fan drive was not designed to transmit 10 hp. The pickup and picking principles offer excellent possibilities for solving some of the harvesting problems referred to by Stout (1958a); however, further testing and evaluation of this machine is necessary before a new design of a machine using these principles is considered. CONCLUSIONS The data presented indicate the following: 1. The picking force depends on the size of the cucumber. 2. The picking force does not depend upon the time of day or the position on the vine. 3. The picking forces differ among varieties of cucumbers. A. The use of a vacuum pickup and elevating device is not limited by the leaf strength. 5. The average specific weight of the cucumbers was found to be 60 pounds per cubic foot. 6. The average specific gravity was 0.96. 7. A relationship was discovered to exist between the weight and length and between the weight and diameter of the cucumbers. It may be expressed as w = kle8L or W = kzebD where W 8 Weight in grams L = Length in inches D = Diameter in inches 56 k1, k2, a, and b = Parameters 8. The pneumatic vine trainer trained the vines without damage to grow perpendicular to the row center. 9. A new mechanical cucumber harvester was invented, designed and constructed. 10. The vacuum pickup and elevating unit on this machine will lift and elevate vines off the ground with the cucumbers hanging down from the vine. 11. The cleated belt picking principle will pick and elevate the cucumbers simultaneously. 12. The pickup unit caused no vine damage. 13. Vine damage due to the picking bed was less than 2 per cent for one harvesting operation. SUGGESTIONS FOR FURTHER STUDY 1. The relationship between weight and picking force should be obtained for most commercial varieties of cucumbers. 2. Investigate the relationship of picking force to size of stem, fertility and other pertinent factors. 3. Study the use of the pneumatic vine trainer while cultivating the cucumbers. A. Use the vine trainer to spread insecticides and to control diseases during the training operation. 5. Further analysis of the effect of the vine trainer on the number of fruit set in the root zone would be desirable. 6. Determine the field picking efficiency of the cleated belt picking principle. - 7. Determine the most efficient height and spacing of the cleats. 8. Incorporate the air output from the fan with the vacuum pickup to aid in lifting the vines. 9.. Consider the use of the air output from the fan for removing root line cucumbers. REFERENCES Allard, Gordon (1956). Mechanical cucumber harvesting. Un- published report. Agricultural Engineering Department Library, University of Maine, Orono, Maine. 15 pp. Banadyga. Albert A. (19119). W L te e lin. ith r d . Nazional Pickle Packers Association, Oak Park, Ill. 27 PP. Beattie, J. H. (1930). Growing cucumbers for pickling. USDA Farmers' Bul. No. 1620. 56 pp. Beattie, W. R. (19h2). Cucumber growing. USDA Farmers' Bul. NO. 1563. “'2 pp. Borsenik, Frank (1955). Mechanical cucumber harvester opera- tion of 1955. Agricultural Engineering Department Library, Mich. State Univ. 1955. Chisholm, J. A. (1955). Michigan men build cucumber harves- ter. Market Growers' Journal. 8h:8. George, Lester F. (1955). The Maryland field conveyor. Market Growers' Journal. 8h(7):6-8. Hall, B. J. (1956). Cucumber pickling made easy. Amer. Veg. Grower. 4(6):2h-25. Hall, B. J. and J. H. MacGillivray (1956). “Mechanical cucum- ber picking. Calif. Agr. 10(1):l3. Hawkins, A. D. (1951). Maine cucumber growers solve their harvesting problem. Market Growers' Journal. 80:16. Hoglund, C. R. (1958). Economics of growing and irrigating pickling cucumbers. Mich. Agr. Expt. Sta. Quarterly Bul. 40(4):?96-805. Peterson, C. E. and S. K. Ries (1958). The evaluation of pickling cucumber varieties for Michigan. Mich. Agr. Expt. Sta. Quarterly Bul. b0(h):932-9 l. Ries, S. K. (1958). Growing pickling cucumbers in Michigan. Mich. State Univ. Ext. Folder F-191 (Revised). 59 Stout, B. A. (1958a). Development of a mechanical cucumber harvester. Agricultural Engineering Department Library, Mich. State Univ. March, 1958. Stout, B. A. (1958b). Development of a mechanical cucumber harvester. Agricultural Engineering Department Library, Mich. State Univ. June, 1958. I ROOM USE GIJIY, ;, J.1 .. z w-fl‘h' HICHIGRN STATE UNIV. LIBRARIES 31293101400616