A potato harvester delivery conveyor with automatic discharge height control

A proportion of the damage sustained by potatoes at harvest time occurs during transfer from the potato harvester delivery conveyor to the trailer. A prototype delivery conveyor, designed to reduce this damage, was built and tested under commercial harvesting conditions. The conveyor has an automatic discharge height control consisting of a sensor ball mounted on the end of the conveyor and actuating an airswitch which causes a solenoid valve to operate a hydraulic lifting ram. The conveyor is in two parts, the distal part being capable of swinging sideways in the event of impact against the trailer tailboard. Results of tests show that the mean drop height can be held within the range 116–199 mm. This is an improvement on the mean drop heights of 390–780 mm measured under typical farm conditions on harvesters without automatic control of the delivery height of the discharge conveyor.