GB1003400A - Improvements in and relating to fluid pressure motors - Google Patents

Abstract

1,003,400. Fluid pressure apparatus. PARKER-HANNIFIN CORPORATION. March 9, 1962, No. 9183/62. Heading F1P. [Also in Division F2] A fluid pressure motor comprises a piston 20 reciprocable in a cylinder 20, co-operating means on the piston and cylinder forming a cushioning chamber 91 when the piston nears the end of a stroke in the cylinder, a port 34 in the cylinder for admitting pressure fluid thereto, an unrestricted passage along the internal periphery of the cylinder connecting the port with the cushioning chamber, and check valve means 54 in the unrestricted passage for permitting fluid flow from the port to the chamber and preventing flow from the chamber to the port. The piston 20 divides the cylinder 10 into first and second chambers 91, 90, and the motor has first and second heads 12, 11 for closing the chambers, the first port 34 being in the first head for admitting and exhausting fluid to and from the first chamber, and a second port 66 in the first head isolated from the first port and connected by a passage 87 to a third port 78 in the second head for admitting and exhausting fluid to and from the second chamber. The passage consists of a tube 87 which is received with end play in recesses 85, 86 in the heads, seals 88 preventing leakage between the tube and heads. The movement of the piston 20 is cushioned at the end of its strokes by restricting the flow of fluid being exhausted from whichever chamber is diminishing in volume and the check valve 54 permits unrestricted flow to the chamber when the stroke of the piston is reversed. The piston consists of a resilient annulus 22 mounted on a plate 21 secured between plungers 28, 29 on a reduced portion 26 of a rod 15. The plungers are adapted to co-operate with sleeves 44, 73 towards the end of the strokes of the piston to prevent flow from whichever chamber is diminishing in volume. The sleeves are mounted so as to move radially on seals 47 in adaptors 40, 71 secured to the heads to accommodate any misalignment between the plungers and sleeves. When the piston is moving to the right and the plunger has engaged the sleeve 44, fluid can only flow from the chamber 91 through passages 61, 58 to the port 34 at a rate determined by an adjustable throttle valve 62 to cushion the movement of the piston. Upon reversal of the direction of fluid supplied to the motor, fluid flows from the port 34 and through slots 75 in the adaptor 40 to an annular space 65. Fluid flows from the space 65 to the chamber 91 past the check valve 54 which is in the form of a packing ring having inner and outer lips. The packing prevents flow from the chamber 91 to the space 65 but permits unrestricted flow in the opposite direction so that the piston can be moved rapidly from its extreme position. The adaptor 71 at the other end of the cylinder operates in an identical fashion to the adaptor 40.