لخّصلي

Tomatoes are a very popular and very frugal fruit, making them very hard to harvest without damage. Until World War II, tomatoes were harvested by hand. During the war the shortages of labor and the high prices forced engineers to look for mechanical harvesters. In trying to develop mechanical harvesters the engineers were faced with two challenges.

1. Since the fruit did not reach maturity uniformly, the farmers had to harvest three or four times a summer or lose profits in unripe tomatoes. Therefore the harvester had to leave the plants undamaged.


2. Since tomatoes were thin-skinned, they had to be handled gently to avoid bruising and cracking. If the fruit were damaged the processors would pay a lower price for them and the growers would lose profits.
   A farmer in Pennsylvania named Garber developed the first mechanical harvester. He extended hammocks from either side of a truck and had workers sit in them and pick the fruit as the truck drove up and down the rows. The workers placed the tomatoes on a conveyor belt that transferred the fruit to the truck.
   Many changes would take place before the first successful mechanical harvester was introduced. One of the changes was the development of tomatoes that would all mature at roughly the same time, allowing for a single harvest. At the same time a number of groups around the country were working to develop a harvester.
   In 1959 Blackwelder Manufacturing Company of Rio Vista California, in collaboration with scientists and agricultural engineers at the University of California at Davis, invented the first successful tomato-harvesting machine. This first machine worked as follows


3. At harvest time the motorized machine was driven down the rows of tomatoes. Each tomato plant was severed a little below the ground level by a blade or rotating disk, then carried to a shaking device by a conveyor belt.


4. Once inside the machine the plants lay on a belt that vibrated with a four-inch stroke at a rate of 175 to 200 cycles per minute, forcing the fruit to drop from the vines. The vines would fall to the ground and the tomatoes were carried to a sorting area by a second conveyor belt.


5. A horizontal conveyor belt transported the tomatoes through the sorting area, where clods of dirt, bad tomatoes and trash were removed.


6. At the end of the sorting area another belt carried the tomatoes to a large bin either pulled behind the harvester or bulled along side by another tractor. A typical bin was usually about four feet square by two feet deep and held half a ton of tomatoes.
   It is the fall from the last conveyor belt to the bin that resulted in the most damage to the tomatoes. The tomatoes fell up to four feet and the first tomatoes in the bin could have hundreds of pounds of tomatoes on top of them. This pressure caused the small splits that were incurred in the fall to enlarge. As a result, approximately one quarter of the tomatoes were damaged and were either unsellable or had to be sold at discount.