Patent ID: 8762001
Filing Date: 2014-06-24
Classification: A01B,B60G

Abstract:
1. A tractor comprising: a traveling vehicle body, the traveling vehicle body having front wheels, the traveling vehicle body being configured to have a ground implement connected thereto; a lift actuator elevating/lowering the ground implement coupled to the traveling vehicle body; a suspension mechanism supporting the front wheels; a draw load sensor detecting a draw load value of the ground implement connected to the traveling vehicle body; draft control means performing draft control, when the ground implement is in a work position, by controlling the lift actuator based on the draw load value detected by the draw load sensor; and mode switching means selecting one of a suspension suppression mode and a suspension function mode with respect to the suspension mechanism, wherein a suspension function of the suspension mechanism is limited or stopped in the suspension suppression mode, and a suspension function of the suspension mechanism is activated in the suspension function mode, wherein the draft control means is configured to generate a raise control signal for controlling the lift actuator to elevate the ground implement; and wherein during the draft control while the ground implement is in the work position, the mode switching means is configured to select the suspension function mode based on non-detection of the raise control signal as long as the draw load value is within its dead zone, and to select the suspension suppression mode based on detection of the raise control signal when the draw load value has exceeded an upper limit value of the dead zone.