초록 ▼

Mounted between a frame and a dozer blade at opposite sides of vertically spaced stabilizing and ball joint connections joining the frame and blade are a pair of hydraulic angling actuators which are operative to angle the blade about a vertical axis defined by the connections. A hydraulic tilt actu

Mounted between a frame and a dozer blade at opposite sides of vertically spaced stabilizing and ball joint connections joining the frame and blade are a pair of hydraulic angling actuators which are operative to angle the blade about a vertical axis defined by the connections. A hydraulic tilt actuator is connected between the frame and blade in the vicinity of the stabilizing connection and is operative to tilt the blade about a fore-and-aft axis passing through the ball joint connection. Pressure relief circuitry including a normally closed relief valve is connected to the angling actuator and the relief valve is opened in response to a predetermined pressure build-up in the angling actuators, as occasioned by changes in the location of the points of connection of the angling actuators with the blade during tilting of the latter, to exhaust fluid from the angling actuators to permit extension or retraction thereof. Poppet valving is provided in the pistons of the angling actuators for interconnecting opposite ends of each of the angling actuators when the latter are at the ends of their respective strokes so as to prevent the pressure from building up in the angling actuators when the blade is tilted.

대표청구항 ▼

In a combination including first and second two-day hydraulic angling actuators connected between a dozer blade and a frame to which the blade is connected by universal connection means located between the actuators and by stabilizing connection means for guiding the blade during angling and tilting

In a combination including first and second two-day hydraulic angling actuators connected between a dozer blade and a frame to which the blade is connected by universal connection means located between the actuators and by stabilizing connection means for guiding the blade during angling and tilting movements of the latter about the universal connection means, a two-way hydraulic tilting actuator connected between the blade and frame, a first conduit means connected between a first direction control valve and a head-end work port of the first actuator and a rod-end work port of the second actuator, a second conduit means connected between the control valve and a rod-end work port of the first actuator and a head-end work port of the second actuator, third and fourth conduit means respectively connected between a second control valve and head and rod-end work ports of the tilting actuator, each of a source of fluid pressure and a reservoir connected to the first and second control valves, the improvement comprising: a pilot pressure conduit means and a reservoir connected pressure relief conduit means respectively connected to one and another of said first and second conduit means; a normally closed, pressure responsive relief valve means located in said pressure relief conduit means and connected to said pilot pressure conduit means and responsive to a predetermined pressure in the latter to assume an open condition whereby pressure induced in said angling actuators by actuation of said tilting actuator will be kept at a value no greater than said predetermined pressure by operation of said bypass valve means.