Patent GB-1208942-A (GB)
Title: Coupling devices for hydraulic lines
IPC: F16L37/30
Filed: 1968-02-13
Abstract: 1,208,942. Pipe couplings. PARKER-HANNIFIN CORP. 13 Feb., 1968 [13 Feb., 1967; 28 Feb., 1967; 29 Nov., 1967], No. 6924/68. Heading F2G. An hydraulic line coupling comprises socket and spigot halves 11 and 12, respectively, each having a spring-closed flow cut-off valve 22 and 39, respectively, and a collapsible spring-loaded strut 54 which exerts a force on each valve tending to open the same on coupling the coupling halves and which can yield to permit the valves to remain closed when fluid under pressure is present in the coupling halves. On insertion of the spigot in the socket, the forward end sealingly engages a sealing ring 80 in the socket body 15 and depresses an internal locking sleeve 24 inwards to permit balls 73 to be released from an internal recess 71 in an external sleeve 51. This latter sleeve is then spring- urged to the right to cause a further set of balls 50 carried in the socket to engage an annular recess 48 in the spigot periphery to lock the spigot and socket together. During this coupling operation, the ball check valve 39 engages a plunger 62 which, together with a second plunger 66 and an interposed spring 70, is slidably mounted in a cage 56 to form the spring-loaded strut which is axially movable itself in a fixed sleeve 55 against a weak spring 61. On the valve 39 engaging plunger 62, the cage is moved to the left until plunger 66 engages the valve 22. If there is no fluid pressure in the coupling halves, the ball valves will both open on further coupling movement as spring 70 is stiffer than the valve closing springs 37, 47. If the coupling halves contain fluid at the predetermined hydraulic pressure, spring 70 is compressed to partially collapse the strut which thus fails to open either ball valve against fluid and spring pressure. Pressure in the socket is then momentarily relieved by operating a valve in the line connected to the socket. The spring 70 subsequently overcomes the valve spring 37 and opens valve 22. Operational pressure is resupplied to the socket half and this pressure together with spring 70 opens the valve 39 against the force of its closure spring and bias of fluid pressure in the spigot coupling half. The socket half is also provided with a spring- loaded piston 77 which prevents an hydraulic lock being formed on insertion of the spigot half should fluid have failed to have drained from the socket through bores in the plungers in its uncoupled condition. In another embodiment, Fig. 4, the valve 152 in the socket, which includes a poppet valve portion 153, is slidably mounted in a fixed cup-shaped shield 138 and urged to its closed position by a spring 175. A hollow plunger 166 is mounted in a bore of the valve and is urged by a spring 168 so that in the uncoupled state, the plunger projects forwardly of the face of the valve. The plunger 166 and spring 168 functionally replace the strut of the previous embodiment. On entering the coupling spigot half into the socket half, ball valve 196 engages the stem. If there is no fluid pressure in either coupling half, as spring 168 is stiffer than either of the valve closing springs, both valves will open. If fluid pressure exists in both halves, the stem is moved to the left to compress spring 168 which still falls to overcome the spring and pressure forces acting on valve 152. Pressure is then relieved momentarily from the socket half permitting the spring 168 to open the poppet valve. Said spring, together with the re-applied operational pressure, then opens ball valve 196. A similar, but simplified embodiment, is also described, Fig. 10, wherein the yieldable spring 288, which is stiffer than springs 278, 232, biasing valves 272 and 234 to the closed position, is contained within valve 272 and is compressed on abutment of a pin 286 by valve 232 on coupling of the coupling halves.