| 摘要 |
<p>1,218,526. Controlling vehicles. MASSEYFEKGUSON SERVICES N.V. 12 May, 1969 [24 May, 1968], No. 24013/69. Heading B7H. A steering and braking system, for an endless track vehicle with steering clutches and brakes, comprises a pair of manual control valves 5 each movable from a first rest position (Fig. 1) successively to a position for initiating movement of a respective hydraulic de-clutch actuator 55 and subsequently to a position for applying a brake 62, and a single sequencing pilot-operated relief valve 1 having a pilot pressure connection 46 to the de-clutch actuator, a connection 2 to a high pressure oil source and a connection 19, 20, 25 and 26 or 27 to a brake actuator 59 constituting a first spill passage from the valve 1. On starting the pump 3, with the valve 5 in the rest position, pressure builds up in the chamber 44 moving the stepped valve plunger 29 to the left until an annulus 21 in a sleeve 11 is uncovered permitting spillage of oil through passages 22, 23 to a reservoir. On movement of the control valve plunger 70 to the left, the gallery 75 bridges galleries 52, 53 allowing oil to flow from pump pressure bore 6 of the valve 1 through pipe 9 to operate the de-clutch actuator 55 and thence through a pipe 46 to a pressure sensing space 43 of the valve 1. The pressure in the space 43 acts on the large end of the plunger 29 to move it to the right until it covers the exhaust passage 22 and partially covers the holes (15) (Fig. 5, not shown) and 18, increasing the pressure in the space 44 until a balance is obtained between the pressures on the ends of the plunger 29 and the plunger 37 is moved to the right permitting the oil to exhaust through passages 38, 42, 34 and 35. Meantime gallery 74 is in register with the gallery 58 permitting the space 44 to vent through the holes 15, pipe 26, gallery 58 and passages 71, 72, 63 in the plunger 70 and brake actuator 59. On further leftward movement of the plunger 70 the plunger nose 77 abuts the actuator 59 to operate the brake directly and to permit a pressure build-up in the interior of the actuator 59, thereby urging it to the left. This increasing pressure acting on the nose 77 is communicated to the driver.</p> |
