GB707254A - Improvements in hydraulic pumps and motors - Google Patents

Abstract

707,254. Reciprocating pumps. BEACHAM HYDRAULIC CO., Ltd., and BEACHAM, T. E. Oct. 15, 1952 [Oct. 22, 1951; Nov. 14, 1951], Nos. 24539/51 and 26680/51. Class 102 (1). [Also in Group XXIX] In a hydraulic motor or pump in which a swash plate 3 mounted on a shaft 1 is driven by or drives pistons 4 reciprocating in cylinders 6 parallel to the axis of rotation of the shaft each cylinder 6 has a separate distributing slide valve 9 associated therewith arranged radially with respect to the shaft and reciprocated by a common eccentric 10 rotatable with the shaft. The cylinders 6 are formed by bores in blocks 20, also bored for the piston valves 9, and located in a carrier 21 clamped between casing parts 17 and 30 by bolts 33 which also act to hold the valve chest portions of the blocks 20 between the carrier 21 and an end cover disc 32. The blocks 20 are aligned and prevented from rotation by studs 55 in the casing 21 having projections 56 fitting into holes between angled surfaces 57 of adjacent blocks. Alternatively, the blocks may be all in one integral piece. The piston valve bore in each block 20 has three annular enlargements 12, 13 and 14, the middle one 13 being in permanent communication with cylinder 6 and the other two 12, 14 being respectively in communication with a liquid supply inlet port 7 and an exhaust port 8 in the end cover 32 by passages 34, 35 and 37, 38 respectively therein and bores 36, 39 respectively in each block 20. Reciprocation of the valve 9 causes its associated cylinder 6 to be respectively placed in communication with the inlet port 7 during the outstroke of the piston 4 and the exhaust port 8 during the instroke of the piston when the machine acts as an hydraulic motor and vice versa when it acts as a pump; in the latter case the pistons 6 are preferably provided with return springs. The valve 9 is moved radially outwards by an eccentric ring 24 mounted on the eccentric 10 and returned by springs 11 acting on a washer 44 mounted on the outer end of the valve. In a modification springs 11 are dispensed with and the valve is positively actuated in both directions by being pivotally secured at its inner end to an eccentric ring. Specification 646,371 is referred to.