Patent GB-787712-A (GB)
Title: Improvements in or relating to pipe couplings
IPC: F16L37/092
Filed: 1955-12-19
Abstract: 787,712. Pipe couplings. CHAMBERLAIN, H. T. Dec. 19, 1955 [Dec. 31, 1954], No. 36359/55. Class 99(1). In a pipe coupling for operating under positive, negative or zero fluid pressure head conditions, a set of slips 45 forming a bore for the reception of a pipe of synthetic plastic material or metal are exteriorly complementary with an inclined camming surface defined by the opening in a cylindrical housing 21 and are disposed lengthwise in that opening, and a resilient annular seal 40 is connected to the inner ends of and provides a cantilever support for the slips. The seal has portions 41, 42 diverging radially beyond the inner and outer surfaces of the slips, so that the outer portion 42 is radially compressed by engagement with the housing and the inner portion 41 is radially expanded by passage of the pipe 22 therethrough, the radial compression of the portion 42 causing responsive diverging movement of the outer ends of the slips and the subsequent radial expansion of the portion 41 causing converging movement of those ends whereby the bore is first made convergingly receptive of the pipe and the slips are automatically engaged with the pipe as the pipe is inserted axially into the bore. As shown in Fig. 2, the housing 20 consists of two hollow, frusto-conical shells 21, 21<SP>1</SP> the internally tapered, wall portions 24 of which terminate in shoulders 27 and receive the correspondingly tapered, outer wall 33 of an annular spacer ring 30. The latter has a transverse wall 32 defining an opening 31, and radially-spaced annular walls 34, 35 extending from opposite sides of the wall 32 to form annular chambers 36, 36<SP>1</SP> ; the wall 34 is provided with a number of slots 37, or holes 38, to allow the transmission of pressure fluid to the chambers which are capped by resilient, annular gaskets 40, 40<SP>1</SP> the walls 43 of which have dovetail-shaped annular grooves 44 for the reception of correspondingly shaped projections 47 of four slip segments 45 formed with toothed or plain inner faces 46 ; alternatively, the dovetail-shaped grooves and projections respectively are formed in the slip segments and walls 43, or other crosssectional configurations may be used. As shown in Fig. 5, the walls 41, 42 of the gaskets are flared outwardly, and, when the gaskets are assembled together with the ring 30 the walls 42 engage between the walls 33, 35 of the ring while the walls 41 rest freely across and extend inwardly beyond the wall 34 of the ring. The shells 21, 21<SP>1</SP> which are of a synthetic plastic material are positioned over the assembly of ring, also of synthetic plastic material, gaskets and slips and are heat or solvent welded together and to the ring to form a unitary structure ; as shown in Fig. 6, the gaskets are caused to pivot radially inward so that the outer ends of the slips diverge outwardly against the inner faces of the shells 21, 21<SP>1</SP> this action resulting in a gap 50 between the slips and shells. The diameters of the openings defined by the walls 41 of the gaskets are smaller than the bores defined by the slips. A pipe 22, for example, inserted into the bore formed by the slips, causes radial expansion of the wall 41 of the gasket 40 and as the pipe passes that wall the assembly of the gasket 40 and slips 45 are moved radially outward to close the gap 50 thereby in effect causing the outer ends of the slips to move radially inwards so that the toothed faces 46 of the slips grip the pipe. The extent of insertion of the pipe is limited by the wall 32 of the ring 30, Fig. 8, and the walls 41 and 42 respectively are radially compressed between the wall 34 of the ring and the pipe and the walls 33, 35 of the ring. Fluid pressure is transmitted to the walls 43 of the gaskets so that the gasket and slip assemblies are driven in opposite axial directions to increase the wedging action caused by the tapered inner walls of the members 21, 21<SP>1</SP> and to drive the toothed faces of the slips into tighter gripping engagement with the pipes. In a modification, the coupling comprises metal shells 61, 63, Fig. 9, connected by a screwthread, and the ring 64 has an elongated outer wall 65, and a single inner and apertured wall 66 which is embraced by the spaced apart annular lips 71, 72 of the gaskets 70, 70<SP>1</SP>. The slips 76 are of metal. In another modification, a fitting 86, Fig. 12, having an internal screw-thread for the reception of a pipe is formed with a shoulder 88 and inner and outer axial walls 90, 89, a central opening 91 being provided in the fitting for the passage of fluid therethrough. The outer wall 94 of a gasket 93 is received between the walls 89, 90, and the wall portion 101 of a shell 98 is secured to the wall 89 which abuts an internal shoulder 100 of the shell. The annular gap 102 between the end of the wall 101 and the shoulder 88 of the fitting co-operates with the arms 103 of a quick-release sleeve 104 slipped over the shell 98 and movable axially to release the gripping action of the slips. In a further modification, the lips 117, 118, Fig. 15, of the gasket 115 are formed adjacent the bases thereof with at least one moulded flap portion 121, 122.