REGULATING WORKING DEPHT OF OMPLEMENT

摘要

This invention is about an automatic position control of tractor ploughshare height. There is a hydraulic device (2) controlled by a controller and lifting a ploughshare in a tractor. The controller includes a speed controlling program, which lifts the ploushshare in a first high speed mode, and downs in a second high speed mode. In the first high speed mode the speed controlling program varies the lift-down speed from low speed to high speed by stages.