| 摘要 |
<p>1,210,168. Reciprocating piston pumps. UNIROYAL ENGLEBERT DEUTSCHLAND A.G. June 6, 1968 [June 8, 1967], No.27000/68. Heading F1A. In a hydraulic pressure system, hydraulic pressure is generated by a reciprocating piston pump in which a pneumatically-actuated piston 3 is connected to a pump piston 7 of considerably less cross-sectional area, and first control valve means 32, 34 selectively admits into the actuating cylinder 2 one of a plurality of pneumatic actuating pressures, and second control valve means 25 selectively connects a discharge line 8 of the pump cylinder to one of a plurality of working lines 23, 24, assigned for operation at the different hydraulic pressures developed in dependence upon the selected one of the several actuating pressures. A reversing valve 11 alternately supplies to each side of the actuating piston 3 pneumatic pressure fed to it via line 8 connected to pressure reducing valves 28 or 29, according to the setting of the first control valve means 34, 35. Operating in synchronism with the valve means 34, 35, the second control valve means 25 selectively connects the hydraulic pressure line to the working line 23 or 24 which, as shown, are connected to the high and low pressure sides respectively of double-acting piston and cylinder devices 17, 18, actuating an external device e.g. die-head clamping devices as disclosed in Specification 1,183,444.</p> |
