GB1405472A - Fluid operating corporation electrical discharge machining apparatus - Google Patents

Abstract

1405472 Fluid-pressure servomoter systems LEESONA CORP 4 Sept 1972 [13 Sept 1971] 41004/72 Heading G3P [Also in Division F2] A device for alternately feeding signals to user lines 62 and 64, wherein the users 66 may be cylinder motors or logic devices, comprises a diaphragm 68 which divides a housing 12 into two chambers 18 and 20. Each chamber forms part of flow path between a common inlet 26 and respective output lines 36 and 38, the upstream ends of the output lines being formed with upstanding seatings 70 and 72, respectively. Con- nected to the output lines 36, 38 are two-state valves 40, 42 which are operable either manually or by air-pressure motors 48, 50, both valves being biased to their closed positions (shown) by springs 46. In operation, on opening valve 42, output line 38 is vented to atmosphere via line 60 and so diaphragm 68 is caused to move, from the position shown, into engagement with seating 72 whereupon it is maintained in engagement with that seating due to a pressure differential thereacross. The differential results from the fact that the side of the diaphragm which is contacting the seating has its effective area reduced by an amount equal to the area of the seating. Operation of valve 40 results in diaphragm 68 returning to the position shown. At the start of an operation, it may be required that the diaphragm engages the same one seating only in which case a restrictor 76 is provided in one of the branched supply lines 28, 30.