MECHANICAL GRAPE HARVEST--- PROBLEMS AND PROGRESS

Transcription

1 MECHANICAL GRAPE HARVEST--- PROBLEMS AND PROGRESS A. J. WINKLER, LLOYD H. LAMOURIA, and G. H. ABERNATHY Departments of Viticulture and Enolocjy and Agricultural Engineering University of California, The tremendous strides made in recent However, only a few varieties fhaf are years in the mechanization of many agri- now grown in California have fairly long cultural operations, including the handling cluster stems. Fortunately, these varieties of picked grapes for wines and the cjafh- furnish many of the grapes that are dried ering of rolled, cured raisins, has sfimulaf- for raisins o are crushed for common ed interest in the harvesting (picking)of wines. grapes by machine. Despite the character Special training is necessary in order of the fruit of the grape and its points fo form a vine which will permit alignment of origin all over the vine, which in the.past made mechanical harvesting appear of all the bearing units on a horizontal trellis. VCifh normally spaced vineyards the impossible progress has been made. fruifincj wood must all be placed on one ' side of the support. Attempts to do this This research was initiated with the fol- with Thompson Seedless were initiated in lowing thoughts in mind. First, if an eco The horizontal crossarm of the trellis, nomical and dependable harvester was fo af 42 fo 48 inches above the ground, was become a reality, a non-selective cuffing placed so fhafifexfended 30 inches on one mechanism must be utilized. Secondly, the side of the row, with 12 inches on the other. fruit clusters could be brought fo a com- Three smooth wires, equally spaced, with mon elevation by bearing unit (fruiting the inner wire S inches from the stake wood) management, were attached fo the underside of the long The fruit of the grape is a cluster of arm. These supported the bearing units berries" the clusters are borne on the and the crop. The short end of the crossshoots arising from the bearing units on arm was solely for bracing. In 1955 simall parts of the head of the vine, and the liar supports were built for Malaga, Misberries are readily subject fo handling in- sion, and Palomino. On some of these juries. In the case of head-trained, spur- the number of trellis wires was increased runed vines, the bearing units are too fo four and on others fo five. With Thomps off fo permit manipulation, which would son Seedless, the fruit canes were fled fo bring the fruit in position fo Be removed the middle one of the trellis wires (Figure by machine. Similarly, the cluster stems of I). In the other varieties long arms were many of the varieties are so short (I/4 fo developed so fhaf the spurs were over IV2 inches)fhaf if is impossible fo remove the inner part (next fo vines) of the trellis them without injury with a rigid yet mov- (Figure 2). As the new shoots elongated able cuffing device even though they were and bent down of their own weight and alined in a horizontal plane, that of the fruit they rested on the upper The above considerations simply indi- surface of the trellis; the clusters hanging care fhaf the mechanization of the grape free below the wires (Figure 3}. This offharvest must Begin with the selection of center load of fruit puts an added strain the variety and the frainincj of the vines, on the trellis. However, the heavy crops The variety is of importance because of 1953, 1954, 1955, and 1956 caused no cluster stem length is a varietal character breakage or tilting in the loam soil af and if must be sufficiently long so fhaf. if may be cut by machine without undue Because the fop of the floating cutter injury fo the Berries. With cluster stems bar of the mechanical harvester rides three or more inches in length mechanical against the unserside of the trellis, cross harvesting would be an accomplished fact. fie wires were employed in an attempt fo 182

2 MECHANICAL GRAPE HARVEST--183 roduction where all of the trays should ~ e placed in the same position between the rows to insure uniform drying. These difficulties in harvesting and the placing of the raisin frays can be overcome by a change in the spacing of new plantings which would make possible the use of a "T" type trellis. For this it is suggested that the rows be spaced IS to 18 feet apart but that essentially the same number of vines be planted per acre. To facilitate row plowing two vines should be adjacent to each other in the row but on opposite sides of the supports. To stabilize the trellis two stakes are driven side by side and sloped out of the row so that they stand 12 inches apart at the height of the crossarm of the trellis. The crossarm is 6 feet long with 30 inches on each side of the Figure I. Cane pruned vines on trellis for mechanical harvesting. improve the supporfin 9 surface o{ the trellis. The three smooth wires permitted shoots and ends of canes to drop below the level of the support to interfere with the removal of the fruit. The trellis with cross wires supported the canes and shoots more effectively, but sagging cross wires became caught in the cutter bar and thus were objectionable. The above ~y~e o{ Horizontal trellis, which brings al {ruiting wood to one side of the row, positions the {ruif {or mechanical Harvesting but leaves much to be desired in the matter of e{ficiency. That is, the space between the rows o{ established vineyards is only wide enough to Have a horizontal trellis on but one side of the rows within a block, Hence the har- Figure 2. Spur pruned vines on trellis for vester will be obliged io travel inactive mechanical harvesting (first year, some of a considerable Dart o~: the time. This these long spurs will be developed into problem is parf:icularly difficult in raisin arms}.

3 !84--MECHANICAL GRAPE HARVEST Figure 3. Thec lusters hanging Below the trellis (side view). supports. Wires on this support are placed that 82 per cent of the fruit was within as above but on each side of the row. the cutting region. These measurements With this trellis the harvester works con- provided the necessary assurance that the tinuously except when turning ancl there is vines could be trained for mechanical hatample space for handling the grapes or vesting. Therefore, the design of the first drying the raisins. Also, by using essen- grape harvester was begun. Research since fially the same number of vines the vine resulted in a machine which was yard will attain full Bearing in the usual placed in the field for the first time in time Although the Basic harvest principle Means of cane, spur and shoot manage- has not changed, modifications in the clement to reduce the hancl work of getting sign resulted in new machines in 1955 and the clusters to hang free below the trellis must still Be improved. The same is true of the surface of the trellis" that is, how DESCRIPTION OF HARVESTER many wires are best. Hand work will a!- The following description covers only ways Be required to free the clusters from the current harvester, with emphasis on the the shoots and wires so they hang free. wine grape handling. The harvester is a This work, however, will come in miclseason tractor mounted unit designed to remove when the demand for vineyard labor is the fruit from the vine and either elevate slack, the wine grapes into a Bulk tank on a A simulated machine harvest on the truck in the adjoining row or place the 1953 Thompson Seedless vines indicated raisin grapes onto a continuous paper

4 MECHANICAL GRAPE 32"Cutter bar (~ Paper Cutter head support (~ Cone Cross Chute for rosin lay (~ Vine lifter (~ Swivel head cylinder ~) Retraction head cylinder (~ Duet boot (~) Cutter bar hydraulic motor Cross conveyor hydraulic motor Cutter head balance cable 141~" \ SIDE ELEVATION Figure 4. Diagramatic sketch of the grape harvester. tray. It removed the fruit by floating a cutter bar along the underside of the special horizontal trellis. The machine is composed of the following elements (Figures 4 and 5): The vine (cane)lifter is a spr!ng loaded sheet metal vine chute: lifts the trailing vines over the fop of the cutter bar. A cane depre,ssor (sheet metal) drags along the top side of the trellis: assists in holding the clusters at a minimum elevation while being cut. A floating cutter bar is required to compensate for wire to ground elevation differences. A net upward force of about 50 pounds, accomplished with a counterbalance, is exerted against the underside of the trellis. The cuf er mechanism is a saw chain with knife sections projecting one inch beyond the chain" a speed of 4170 feet per minute was maintained through the use of a hydraulic motor and vee belt drive. A ;1 feature on the cutter bar permits the bar +o closely follow the wire, even when the trellis is not perfectly horizontal or even when the tractor is not on a level surface. Culler bar profecflon is provided with an oil cylinder connected to an accumulator that holds the cutter bar perpendicular to the tractor yet permits the bar to swivel when obstructions are met. A side conveyor, hydraulically driven, receives the falling fruit and moves if to the elevator. The elevator, an inside-out chain flight design, hydraulically driven, continuously elevates the fruit to the adjoining row. Its 9 foot clearance permits trucks with bulk tanks to drive into position for loading. A lifter for he cane depressor and a cutter bar lowering mechanism permits entry into a new row. PERFORMANCE The harvester was operated af speeds ranging from 0.4 to 1.6 miles per hour. Because it is difficult for the operator to

5 186--MECHANICAL GRAPE HARVEST Figure 5. The harvester in operation. gauge fhe position of fhe culler Bar relative fo fhe slake, if has Been necessary fo operafe af 0.5 mph. The lower speed also resulted in a higher cuffing efficiency. The following fable shows some of the harvest results to date. Variety Location Results of Mechanical Harvest Percentage of Fruit Left below Left a bore Harvested wire wire Malaga Mission Palomino Thompson Seedless Delano.... :. Fresno Madera II I : II

6 MECHANICAL GRAPE HARVEST--187 PROBLEMS grapes per hour. Before the machine is ready for adoption by the industry, addi- The figurescof n the fable not only in- fional research is required fo increase dicafe what be expected the the effectiveness of the cutter, provide harvester but they also show the lack a leaf remover and a sensing mechanism of sufficient care in shoot and cluster managemenf. Fruit above the wires of the for automatic steering. trellis obviously is inaccessible fo the machine. If should not have been left there. ' REFERENCES Likewise, some of the fruit below the wire Lamouria, Lloyd H. Progress report" on mawas not low enough for the machine to chine picking of grapes. Western Farm Equipcut the stems of the clusters, ment, 51 (I I):26, November The design is based upon a harvester Winkler, A. J., and Lamourla, Lloyd H. Maspeed of I.S miles per hour. This harvest chine Harvesting of grapes. California Agriculrate is expected to remove 1.7 acres of lure, 10 (S)" 9, 14, May 1956.