Development of an Impact Type Electronic Weighing System for Processing Tomatoes

摘要

Two impact type electronic weighing devices were developed and tested during the 2004 and 2005 tomato harvesting seasons. The devices consist of a simple impact plate and a magnetic pickup type harvester boom conveyor speed sensing system. The impactplate was mounted over four load cells in one design and a single load cell in the other design to sense the impact force. The total mass of the tomato weighing system was less than 35 kg, thus making it easy to handle. It was retrofitted on to two commonly used makes of tomato harvesters. In operation, tomatoes impacted the plate as they dropped off the harvester boom conveyor. The impact force and conveyor speed data were recorded on a data logger. The data were analyzed to estimate the weight of thetomatoes harvested over a desired length of transects such as 30 m. The devices were calibrated over 2004 and 2005 growing seasons. The systems worked quite well indicating the potential for weigh buckets based on the impact principle. However, more tests are necessary to validate these devices. Plans are underway to conduct additional tests during the 2006 harvesting season.