Patent GB-857583-A (GB)
Title: Improvements in or relating to plug-and-socket couplings, for example for fluid lines
IPC: F16L37/34
Filed: 1957-03-11
Abstract: 857,583. Pipe couplings. HOFFSTROM, B. N. March 11, 1957 [March 12, 1956], No. 8010/57. Class 99(1). [Also in Group XXXII] In a quickly-disconnectible plug and socket coupling, the socket comprises a tubular socket member 34 and an annular member 98 connected thereto so as to permit relative axial movement between the members from a first to a second relative axial position, and a number of axially-extending fingers 80 distributed about the axis of the member 34 and mounted at one end thereof, the free ends of the fingers being radially movable by co-operating means on the member 98 between first and second radial positions corresponding respectively to the relative axial positions of the members 34, 98. There are means carried by the socket member to limit inward displacement of the free ends of the fingers. The socket member 34 is provided with inner and outer, annular, sleeve sections 38, 40, the sleeve 38 having integral, inwardly projecting ribs 46 of streamlined section formed with a fixed valve seat element48 including an inwardly facing conical surface 50 and an outer plane surface 52. Adjacent the outer end of the sleeve 38 is a boss 56 formed with an annular groove 58 in which is received an O-ring 62, Fig. 4, and a ring element 64 of material having a low coefficient of friction, e.g. " Teflon " (Registered Trade Mark), the boss slidably supporting a sleeve valve 68 biassed outwardly by a spring 70 such outward movement of the valve being limited by an annular shoulder 76 that abuts against an inwardly projecting indentation 78 formed in each of a number of circumferentially spaced, metal, latch fingers 80 having outwardly bent portions 82 lockingly held by a sleeve 84 in a recess 86 in the body 34. The bore 88 of the valve sleeve 68 has an annular groove 90 for an O-ring 92 and encircles the peripheral surface 54 of the member 48. The indentations 78 of the fingers 80 are supported against radial inward movement by a cylindrical surface 96 on the valve sleeve 68 and when the coupling members are in the position shown in Fig. 1, and the outer surface of the indentations are engaged by an annular shoulder 102 of the spring biassed latch-ring 98 mounted for limited axial sliding movement on a shoulder 100 of the sleeve 40 ; the free ends of the fingers are received in an annular recess 104 in the latchring. Those portions of the latch-ring engaging the body 34, and the inner and outer surfaces of the free ends of the fingers 80 are coated with molybdenum disulphide to promote free sliding movement of these parts. The plug member 32 comprises a main body 110 having stepped bores 116, 118, the latter bore being screw-threaded to receive an annular extension member 120 formed with an annular groove 122 having a cross-section conforming to the indentations 78 of the fingers 80. An annular lip 124 at the free end of the member 120 is received in a recess 126 formed in the sleeve valve 68, a wall of the recess being engaged by an O-ring 130 housed in a groove 128, formed in the lip. A valve 146 having a planar end face 148 is integrally joined by radially extending, streamlined, ribs 152 to a sleeve 150 slidably engaging the stepped bores 116, 132 of the body 110 and member 120 and is biassed outwardly by a spring 158 so that, when the plug and socket are uncoupled, a stop shoulder 160 on the valve contacts an inclined shoulder 138 on the member 120 and an O-ring 156 fitted in a groove 154 in the valve is brought into sealing engagement with a bore 134 of the member. Assuming the socket 30 to be held against axial movement, the lip 124, Fig. 2, of the member 120 is entered into the recess 126 of the sleeve valve 68 to push the latter inwardly of the socket, the fixed valve element 48 simultaneously moving the valve 146 away from the sealing surface 134, and the member 120 moving under the indentations 78 of the fingers 80 until the groove 122 is brought into register with the indentations when the latter are cammed into the groove by the latch-ring 98 which moves outwardly to a position whereby the shoulder 102 thereof engages and holds the fingers in locking position. Retraction of the latch-ring 98 allows the plug and socket to be disconnected by a direct pull on the plug or ejection of the plug by the combined forces of the springs 70, 158. Alternatively, the plug 32 or the latch-ring is held stationary. In the coupled position of the plug and socket the groove 121 of the member 120 is completely covered by the latch-ring and provides an indication of the stage of coupling of the two parts ; that groove may be replaced by a scribed or painted line or band. In a modification, the latch-ring 98, Fig. 6, carries a sealing structure 162 engaging the inner surface of a ring 164 secured to the socket 30, and the ring 164 is provided with a sealing structure 168 engageable with the outer surface of the latch-ring, the two structures, similar to that shown in Fig. 4, forming a chamber 172 connected to a fluid pressure line 174 so that by selectively connecting the chamber to pressure or exhaust disconnection of the coupling by retraction of the latch-ring may be made by remote operation. Also, the spring 106 is replaced by a spring comprising sheet metal strips 176, 178, Fig. 7, having reversely folded, circumferentially off-set portions 180, 182 between which one or more spring steel strips 184, which when relaxed are planar members, are bent to yieldingly bias the strips 176, 178 apart. The sockets may be adapted for installation within a tank. In another modification, the coupling incorporates a latch mechanism for locking the parts 186, 190, Fig. 8, in coupled relation wherein the valves may be disposed in positions between the fully open and fully closed positions, and the socket body 192 is provided with a fixed valve seat element 194 connected by ribs 202 to a sleeve 200 screwed at 196 into the socket, and an axially slidable valve 204 biased towards a closed position on to the element 194 by a spring 212 and sealed on that element by an O-ring 208 and on the socket by an O-ring 210. The latch mechanism comprises a number of free-floating, spring-biased, latch fingers 214 and a number of yielding, spring-biased fingers 216 rigid with the body 192 which is slidable within a latch sleeve 218 received in an opening 224 in a wall 222, the outer ends of the fingers 216 being provided with V-shaped wedge sections engageable by corresponding inclined surfaces on the sleeve 218 and fingers 214. In a further modification, the plug body 242 includes concentric inner and outer sleeves 244, 246 and a valve seat member 254 mounted by spaced ribs 252 within the body, there being an axially slidable sleeve valve 256 carrying O-rings 262, 264, and biassed to a closed position and against a stop-ring 260 mounted in the sleeve 246, and the socket includes inner and outer sleeves 270, 272 and a valve seat element 276 mounted by means of ribs 278 within the bore of the socket, a sleeve valve 280 slidably mounted on the sleeve 270 being provided with an O-ring 282 and an annular lip 284 adapted to establish a seal with an O-ring 288 mounted in the valve 256. Mounted for limiting sliding movement in a annular notch 298 of the valve 280 is a ring 300 having a number of spaced teeth 302 formed to lockingly fit within a mating formation of a latch ring 304 slidably mounted on the socket, and a number of circumferentially spaced, spring latch fingers 306 extending between the teeth are provided at the outer ends thereof with projections 312, 314 respectively adapted to fit within groove 316, 318 of the latch ring and sleeve 246 of the plug. A latch finger support member 320 on the valve 280 is biased by a spring 322 towards a stop-ring 324 on the valve, and a spring 326 biases the rings 300, 304 to the left as seen in the Figure to the extent permitted by movement of the ring 300 in the notch 298. As shown in Fig. 10, the valve assembly of the plug comprises an inner main valve 344 and auxiliary valve 348 slidable thereon, both valves having registering passages 350, 352 providing for fluid flow when the valves are open. The valve 348 seats against the adjacent wall of a ring 354 formed on the valve 344 and against the opposite wall of that ring seats a ring 356 provided with spaced L-shaped teeth 358 which if, when the coupling members are uncoupled, the valve 344 is accidently subjected to external pressure and moves inwardly of the plug will tilt slightly and bind against the inner surface of the plug to establish an effective lock against further inward movement of the valve ; the teeth may be replaced by wedging discs mounted between the bore of the member 336 and an inclined shoulder on the valve 344. As shown in Fig. 12, a sleeve 386 rigidly secured to an annular fitting 380 encloses a valve and latch mechanism comprising a valve seat member 390 secured by ribs 392 to an annular member 394 having an L-shaped integral ring 398 slidable within the sleeve 386 and carrying spring latch fingers 416, and a sleeve portion 400 slidably received within the bore 382 of the fitting 380, the sleeve valve 404 being mounted for axial sliding movement on the boss 406 of the sleeve portion 408 of the member 394. The valve is biased on to the member 390 by a spring 414, and an outer latch ring 420 is slidably mounted within the sleeve 386 and biased outwardly towards a stop ring 422 by a spring 424. When the line pressure exceeds a predetermined value the member 394 moves against the force of the spring 424 and the plug is uncoupled and ejected from the socket. As shown in Fig. 13, the socket body 430 has stepped bores 432, 434,the latter bore having an annular chamber 440 communicating with a tapered passage 438, and slidably received within that bore is a valve element 442, provided with an annular opening 447 in alignment with the chamber 440. Ribs 448 rigid with the element 442 mount a valve seat element 450 and t