| 摘要 |
<p>HYDRAULICALLY TILTABLE AND ANGLABLE DOZER BLADE AND MOUNTING THEREFOR 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 changed 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.</p> |
