Patent GB-997232-A (GB)
Title: Improvements in or relating to liquid motion transfer systems
IPC: F15B7/10
Filed: 1961-08-14
Abstract: 997,232. Hydraulic apparatus. EARL THOMPSON MANUFACTURING CO. Aug. 14, 1961 [Aug. 23, 1960], No. 29341/61. Heading FIP. [Also in Divisions B3 and F2] Apparatus for interrupting the sequence of operation of a motion transmitting system having a liquid column 62 connected between an expansible-chamber type transmitter 34 and an expansible-chamber type receiver 50 comprises means 110 associated with the liquid column for maintaining the receiver stationary at a certain position while the transmitter continues in operation. The motion transmitting system may consist of a number of transmitters 34 connected by liquid columns 62 with receivers 50, 56, 60 controlling parts of a grinding machine, receiver 50 serving to feed workpieces to the machine and the other receivers moving the workpiece in a certain manner while it is being ground, ejecting finished workpieces, operating gauging and sorting mechanisms and operating a trueing tool to dress the grinding wheel. Each transmitter comprises a piston 32 reciprocated by a rod 30 having a follower 16 engaging a cam 12 on a shaft 10 driven directly or by a variable speed reducing unit 26 from a motor 24, the movement of the piston displacing liquid in the column 62 to reciprocate the piston of the receiver against the pressure in an accumulator RO. The stroke of the pistons of the transmitters is greater than that of the pistons of the receivers and excess liquid from the transmitters passes through relief valves 72 to a reservoir. Each relief valve has a poppet 78 movable against an adjustable spring 84 when the pressure in the column 62 exceeds a predetermined valve. A ball 92 is pressed against a bore in the poppet by a light spring 94 so that should the pressure in the column fall below that in the reservoir as a result of leakage, liquid can pass from the reservoir to the column. Disposed between the transmitter 34 associated with the receiver for feeding the workpieces and its relief valve assembly 72 is the means 110 which is sequentially operated and consists of a valve assembly having three sleeves 122, 130, 130<SP>1</SP> and a spool 140 movable downwardly against a spring 148 when fluid pressure is supplied to its upper end. The supply of fluid pressure is controlled by a valve 150 movable against a spring when a solenoid is sequentially operated by a control means 17 which may be a manually-operated push button or a counter or other measuring device operated by a device 154. In the position of the spool 140 shown in Fig. 4, liquid displaced by the transmitter piston 32 passes through ports 136, 116 and 160 to the column 62 to actuate the receiver 50, the liquid also having access to the relief valve assembly 72 through ports 128, 118. When the control means 17 actuates the solenoid-operated valve 150 to connect the space above the spool 140 to exhaust, the spring 148 moves the spool to its upper position wherein the ports 136 are closed to prevent flow to and from the column 62 and the receiver piston is held in whatever position it occupied when the valve was operated; the liquid displaced by the transmitter piston when the spool is in its upper position passes through ports 128 to the relief valve assembly 72 and port 26 to the reservoir 74. The sequentiallyoperable means 110 can be reassembled with the sleeve 130, 130<SP>1</SP> transposed and a plug 162 removed from the position shown in Fig. 4 and inserted in the threaded bore 160 so that when the spool 140 is in its lower position liquid displaced by the piston 32 passes through ports 128 to the column 62 and when the spool is in its upper position, the pressure in the accumulator RO urges the piston of the receiver 50 to a rest position at the end of its stroke, the liquid displaced from the column and that displaced by the transmitter piston passing through ports 136 which are adjacent and co-operate with the port 76 leading to the reservoir.