GB956486A - Improvements in or relating to fluid pressure operated reciprocating systems - Google Patents

Abstract

956,486. Fluid-pressure apparatus. F. W. McCONNEL Ltd., and H. W. NORTON. Aug. 9, 1962 [Aug. 9, 1961], No. 28850/61. Heading FIP. A fluid pressure operated system comprises a generator of pressure pulses, one or more sets of relatively reciprocatable plungers and cylinders, and valve mechanism actuated by the pressure pulses and arranged to place an end of a cylinder, or each cylinder, alternately into communication with the generator, whilst generating a pressure pulse, and a lower pressure source. The valve mechanism may comprise a spool having lands 25, 26, Fig. 1, reciprocatable in a bore 23 parallel to the cylinder 12 which contains a plunger 10. The valve controls the communication between passages 28, 29 alternately supplied with pressure pulses from the generator and passages 32, 33 leading to the ends of the cylinder, and communication between passages 32, 33 and a passage 22 leading to a low pressure zone. When a pressure pulse is received from the passage 29, the valve moves to the position shown so that the pressure can act in the right hand end of the cylinder, fluid from the left hand end of the cylinder passing through passage 32 to passage 22. The ends of the cylinder between the ports 34, 37 of the passages 32, 33 and further ports 36, 39 have enlarged diameters to damp the movements of the plunger 10, one-way valves 35, 38 opening on receipt of a pressure pulse to permit access of the pulse to the end face of the plunger. Leakage of fluid between the rod 13 of the plunger and parts 14, 16 is led by a passage 17 to a passage 19 connected to the passage 22. In another arrangement of motor, the plunger is replaced by a pair of pistons 132, 133, Fig. 9, which embrace an output member 134 and reciprocate in cylinders 130, 131, alternately connected to the passages 28, 29 by the valve 25, 26. The cylinders have recesses 140, 141 which receive the ends of the pistons to cushion their movements. In a similar embodiment, the closed ends of the cylinders are adjacent one another and the outer ends of the pistons engage a U-shaped output member. The generator of pressure pulses may comprise a pair of cylinders 58, 59, Fig. 4, containing pistons 56, 57 which are interconnected by a rod having a pair of rollers 62, 63 embracing a cam 64. Rotation of the cam reciprocates the pistons to send pressure. pulses through the passages 28, 29 to the valve mechanism and motor. The displacement of the pistons 56, 57 may be greater than that of the plungers of the motors, the excess fluid displaced being passed by non-return valve 70 to a passage 69 having a relief valve 73 leading to a reservoir 60 from which fluid can pass to the cylinders 58, 59 through a non-return valve 67 or inlet 68. In another arrangement of generator, rotation of a shaft 125, Fig. 8 of a prime mover is converted into reciprocation of a piston 123 by connecting the shaft 125, by means of a coupling 126, ... 129, to the rod 121 of the piston and forming the ends of the piston with sinuous edges for engagement with rollers 124 mounted on the end walls of the cylinder. In other forms of piston-and-cylinder generators, the piston is reciprocated by a crank mechanism, the cylinder either being stationary or mounted to oscillate about a pivot and being connected by flexible pipes to the passages 28, 29. In another form of generator of pressure pulses, the passages 28, 29 of the motor are connected to a casing having a valve 142, Fig. 2, which is rotated and has recesses 145, 146 which alternately connect a passage 140 leading from a pump to the passages 28, 29, the exhaust sides of the motor being connected to a passage 141. Fig. 5 shows an arrangement for reciprocating a vegetation cutter 74 which is connected to the rod 13 of a motor joined by passages 28, 29 to a rotary valve 80 supplied with fluid pressure from a pump 81. The pump also supplies fluid to motors 75, 76 for moving the cutter up and down and fore and aft on a tractor, the motors being controlled by valves 86, 89, 92, 96. Specification 956,485 is referred to.