| 摘要 |
1,060,347. Hydraulic control circuits. CATERPILLAR TRACTOR CO. Aug.3, 1965 [Aug.11, 1964], No.33110/65. Heading F1P. A hydraulic motor (20) Fig. 2 (not shown), for lifting an arm (16) is supplied by a pump (32) through a line (36), a control valve (34) of the spool type and a line (68); the spool (52) of the valve (34) being held in the supply position against the action of a spring (62) by a disconnectable link between it and the spool (126) of a slave valve (S) and which link is broken at the end of the lifting stroke of the motor (20) by the spool (126) being displaced against a spring (90) by pressure fluid directed from a branch line (120) of line (68) through a further spool valve (110) actuated by the arm (16) whereby the motor (20) is disconnected from the pump (32). The housing (124) of valve (S) has a restricted orifice (138) whereby trapped air may be vented to a reservoir (30). Pressure is maintained in supply line (68) until the spool (52) is displaced manually to the right to effect the return stroke of the motor (20). The arm (16) carries a cam for actuating valve spool (112) at variable stroke lengths of the motor (20). |
