Patent GB-765240-A (GB)
Title: Improvements in or relating to hydraulic pumps or motors
IPC: F04B1/24
Filed: 1955-01-13
Abstract: 765,240. Reciprocating pumps. POTTS, F. C. (Eastman Pacific Co.). Jan. 13, 1955, No. 1041/55. Class 102(1) [Also in Group XXIX] A rotary hydraulic pump or motor comprises a fixed body 10 having an internal cavity 14 closed at each end by end plates 11, 12 the cavity having two angularly disposed adjoining cylindrical sections with their axes intersecting, a cylinder block 15 rotatably mounted in each cylindrical section and providing between them a central space in the cavity 14, each block having a plurality of cylinder bores 18 parallel to its axis and a plurality of angular piston members 20 slidably mounted in corresponding bores 18 of the two cylinder blocks 15 and drivingly interconnecting the blocks. The cylinder blocks 15 are free to move a small amount axially to provide space for a fluid film between each cylinder block and the adjoining end plates and to allow the cylinder blocks to be seated against the fluid films by intermediate pressure which builds up in the central space, the effective area on the outer end of one cylinder block 15 bearing against said fluid film being equal to the similar area on the other block. The end plate 11 is provided with an inlet connection 25 and an outlet connection 27 which communicate respectively with arcuate ports 28, 29 with which the cylinder bores communicate as the block rotates. The port 28 is connected by a passage 33 to a similar port 31 in the end plates 12. A recess 32 corresponding to the port 29 is provided in the end plate 12. One block 15 is provided with a central recess 44 which is connected by a passage 43 to the inlet port 28. The other block 15 is driven by a shaft 37 and is provided around the shaft with a recess 38a which is connected through the bearing 40 for the shaft 37 to the inlet port 31. A passage 46 is provided in the housing 10 and extends between the end plates 11, 12 and communicates with the central space. The housing 10 is provided with a further passage 35 corresponding to the passage 33 so that the delivery of the pump may be reversed by turning the end plates 11, 12 through 180 degrees. In a modification, Fig. 13 (not shown), the port 29 is duplicated in the end plate 12 and the passage 35 connects the two ports, and the recesses 44, 38a are connected to the inlet and outlet ports by passages which are controlled by four valves. In this embodiment reversal of delivery is obtained by reversing the direction of rotation. In a further embodiment the inlet and outlet connections are provided in the body 10; each end plate has inlet and outlet ports which are connected by passages in the body and the pistons 20 are solid. The Specification gives formulµ for calculating the diameters of the recess in the end face of the block, for the outside diameter of the cylinder blocks and for the area of the annulus defining the ends of the cylinder bores 18, in relation to the crosssectional area of the bores in the cylinder block. In order to maintain the end face of the block and end plate parallel the end plate may. be tilted by an amount corresponding to the tilt of the block.