GB1465261A - Fluidic switching devices and an inflatable matress controlled by such devices - Google Patents

Abstract

1465261 Valves J G PASSMORE 30 Jan 1974 [6 Nov 1972] 51089/72 Heading F2V [Also in Divisions A4 G3 and G4] A fluidic device incorporates a valve, Fig. 3, comprising a length of flexible tubing 30 extending between two relatively rigid mounts as shown. The mounts are movable by pressure operable actuating means towards and away from one another in a direction substantially transverse to their axes between the valve-open position shown and the valve-closed position in which the tubing becomes kinked. One such fluidic device is in the form of a fluid logic NOR gate, Fig. 5, having a supply conduit 40, output conduit 50, exhaust conduit 42 and control conduits 44, 46. The latter are connected with inflatable bags 64, 62 acting upon a spring- loaded control lever 52 carrying the output conduit 50. In use, if no fluid pressure is supplied to either conduit 44, 46, the control lever will adapt the position shown wherein valve 56 is open and fluid from the supply 40 is thereby discharged through output 50. If fluid is supplied to one or both of the conduits 44, 46, the consequent inflation of the bag or bags pivots the lever upwardly to close the valve 56 and open a valve 58 whereby the output 50 is connected to exhaust 42. In an alternative gate, Fig. 6 (not shown), the control lever is replaced by a spring-loaded control plate which is merely raised and lowered by the inflatable bags and carries a pair of transfer conduits (68, 70) associated with flexible tubing functioning as valves in a manner similar to the Fig. 5 embodiment, to deliver supply fluid to a manifold (64) communicating with a fixed output conduit (50), or to exhaust the manifold to atmosphere. The gates may comprise more than two control inputs and associated bags, or the fluid supply and exhaust conduits may be transposed to provide an OR gate, or a single control input may be provided to produce a NOT gate or inverter. The bags may be such that they both have to be inflated to cause switching to thereby provide a NAND gate or, with the exhaust and fluid supply conduits transposed, and AND gate. The bags may be of different sizes. Means may be provided for restricting the extent to which each bag can inflate, Fig. 7 (not shown). Two NOR or NAND gates may be interconnected to form a crossed NOR or NAND gate bi-stable circuit, Fig. 8 (not shown). Two such bi-stable circuits may be interconnected in a ring circuit, Fig. 8a (not shown), to form an oscillator. Practical constructions of the gates of Fig. 6 are described with reference to Figs. 11 to 16 (not shown), a plurality, e.g. four, of which can be stacked on top of one another to form a compact unit, e.g. a ring circuit oscillator, Figs. 17 to 21 (not shown).