| 摘要 |
<p>1,246,811. Reciprocating pumps. APPLIED POWER INDUSTRIES, Inc. Aug.14, 1968 [June 18, 1968; Aug.14, 1967], No.36054/68. Heading F1A. A swash-plate pump has an end-plate 16 with spring-biased by-pass valves, each of which comprises a poppet with a closure member 74 attached via a stem 76 to a piston 78 and being held off its seat 72 by a control pressure applied through passages 62, 60. In the embodiment of Fig. 1, the by-pass valves are disposed in passages that connect pumping chambers 46 to the inlet chamber through passages 70, 64 and passages 32 formed within a sleeve 28. As shown, the pumping chambers are each connected to a common outlet manifold 42 through check valves 44. Alternatively, some of the pumping chambers may have individual outlet connections isolated from manifold 42, Fig.2 (not shown), or separate manifolds may be provided for groups of pumping chambers with by-pass valves controlled by different control pressures in separate control passages, Figs.6 and 7 (not shown). In Fig.5 (not shown), the by-pass valves are disposed axially in the end-plate and each comprises a spring-loaded ball valve engaged by a stem on the control piston, the control pressure passages being formed as grooves in a separate cover member secured to the end-plate.</p> |
