This invention relates in general to crop harvesting machines and, more particularly, to a header adapted for harvesting vine crops.
Vine crops such as cucumbers have traditionally been harvested using field workers to hand pick the crop as it matures. Because of the labor intensive nature of manual picking, increased attention has been directed to the use of machines to harvest such crops. Mechanized harvesters which have heretofore been used generally include a cutting blade which severs the vines at or below the ground surface. A rotating forward roller with projecting fingers picks up the severed vine mat and additional rotating rollers or conveyors then transport the vine and crop to devices such as closely spaced pinch rollers which separate the crop from the vine. The crop is then conveyed to a hopper attached to the harvesting machine and the vines are returned to the field.
Mechanized harvesting of this type is known as onceover or single-pass harvesting as the entire crop is harvested and the vines are destroyed during passage of the harvester. Since only one crop is obtained from each vine growth, it is critical that the harvesting machine operate with the utmost efficiency and reliability to maximize crop yield. Yet, many conventional machines experience an unacceptable loss of as much as a third of the crop during harvesting operations. These losses generally occur as the crop is dislodged by the sudden lifting action of the rotating fingers lifting of the vine from the ground and as the vine is conveyed rearwardly along adjacently positioned rotating rollers.
In an attempt to reduce crop losses during pick up and transport of the vine mat, some conventional machines use reciprocating or pivoting fingers to achieve greater extension of the fingers during lifting of the vine. The fingers extend or pivot outwardly to their maximum extension along their upward rotation arc to provide more reliable support for the crop. The fingers then retract along their downward rotation arc to permit closer positioning of the adjacent roller. The pivoting of the fingers however, increases the rotational speed of the fingers and increases crop losses during lifting of the vine mat from the ground. The reliability of the cams, bushings and other mechanisms required to operate fingers of this type has also proven to be less than desired, due in large measure to the wear caused by the dirt, rocks and other debris encountered during operation.
Dirt which is carried onto the conveyor with the vine roots also adversely affects the performance of conventional harvesting heads. Especially during wet field conditions, the soil is not adequately dispersed from the harvester head and the conveyor mechanism becomes plugged and/or other components become fouled. Under such conditions, the harvesting operations must be frequently halted for cleaning of the harvester or inefficient transfer and separation of the crop from the vine as well as increased risk of mechanical breakdown will result. A need has thus developed for an efficient and reliable harvesting head which operates with minimum maintenance even under adverse conditions which may be encountered during harvesting operations.