GB562368A - Improvements in, or relating to, pumps for use in hydraulic transmission of power - Google Patents

Abstract

562,368. Reciprocating pumps. TURNER MANUFACTURING CO., Ltd., and GROVES, W. R. April 25, 1942, No. 5558. [Class. 102 (i)]. For the hydraulic transmission of power on aircraft or for presses, two double-acting differential piston pumps are operated from the same source of power during the main part of the transmission of power, one pump being byepassed automatically when the delivery pressure rises to a predetermined value. The pumps may be operated by hand or by power, and preferably the byepassed pump is of larger capacity than the other. In the form shown, two similar pistons D, E are reciprocated in cylinders B, C by the short and long arms f<1>, f<2> of a pivoted lever F, connecting rods d, e, and hollow piston rods e<2> which have a crosssectional area half that of the pistons. Each of the latter has a deep groove e<4> containing a shallower rubber packing ring e' and connected by ports e<5>, e to the spaces below and above the piston. The non-return spring-controlled inlet valves H rest on rubber seatings h<1>. The delivery passage J is connected directly to the cylinder B, and to the cylinder C by way of a passage K with a spring-pressed non-return ball valve k, an annular-passage m<3> in a sleeve m, and the upper part of cylinder B. The sleeve m contains a plunger M which is pressed upwards by a spring m<1>, has an enlarged head m<2>, and has an annular groove m' connected by passages m<5>, m<6> to the inlet G. A passage N leads from the passage K to a space n above the sleeve m so that at a high delivery pressure the plunger M is depressed, the groove m<4> coincides with the recess m<3>, and the cylinder C is byepassed. Specification 546,420 is referred to.