Patent ID: 8414010
Filing Date: 2013-04-09
Classification: B60D,Y10T

Abstract:
1. A fluid circuit to selectably control a position of a first end of a drawbar between a locked position and a suspended position with respect to a drawbar support, the drawbar securable to a work vehicle distal from the first end, the fluid circuit comprising: a first control valve comprising at least a raising position, a neutral position and a lowering position, with one of the positions of the first control valve being selectably in fluid communication with a first port and a second port, the first port of the first control valve connectable to a source of pressurized fluid flow, the second port of the first control valve connectable to a first accumulator; a fluid cylinder in fluid communication with the second port of the first control valve to operate the fluid cylinder between a retracted position and an extended position, the fluid cylinder operatively connected to selectably control the position of the first end of the drawbar by operation of the fluid cylinder; and a second control valve in fluid communication with the fluid cylinder comprising at least an open position and a locked position, with one of the positions of the second control valve being selectably in fluid communication with a third port and a fourth port, the third port of the second control valve connectable to the fluid cylinder, the fourth port of the second control valve connectable to a second accumulator; wherein to selectably move the first end of the drawbar toward the locked position, the first control valve is selectably actuated to the lowering position and the second control valve is selectably actuated to the open position, until a support structure operatively connected to the fluid cylinder urges the first end of the drawbar into abutting contact with the drawbar support, and to maintain the first end of the drawbar in the locked position, the first control valve is selectably actuated to the neutral position and the second control valve is selectably actuated to the locked position; wherein to selectably move the end of the drawbar from the locked position to the suspended position, the first control valve is selectably actuated from the neutral position to the raising position and the second control valve is selectably actuated from the locked position to the open position.