Patent EA-004842-B1 (EA)
Title: Pipe coupling
Inventor: CHELCHOWSKI DAVID
IPC: F16L47/04
Filed: 2002-04-19
Abstract: 1. A coupling for connection of a polymeric pipe, said coupling including: a hollow body having an external thread extending at least in part theralong and having an inner surface; a nut threadably engaging said body external threads, said nut having at one end an internal thread co-operable with said body external thread and including a hooked projection adapted to extend over at least part of said body inner surface said projection including a first inner surface generally parallel to said body inner surface, a second outwardly converging surface extending from the inner edge of said inner surface; a deformable gripping member having a first surface generally parallel to said body inner surface and having a second outwardly converging outer surface extending from said first surface, said member including radially inward barbs; wherein upon tightening of said nut, said nut second surface abuts against and exerts a force on said gripping members second surface both in the longitudinal and radial directions to thereby cause the grip ring to be urged both radially and longitudinally into the body, said nut first surface sliding alongside said body first surface. 2. A coupling as in claim 1 wherein when said grip-ring has moved sufficiently radially inwardly it has engaged the pipe to thereby drag it into the body. 3. A coupling as in claim 1 or claim 2 wherein upon further tightening of the nut, said grip-ring second surface is caused to slide inwardly against the nut second surface. 4. A coupling as in any one of the above claims wherein said body inner surface is tapered and diverges outwardly of the body so that upon tightening of said nut as the grip-ring moves into said body a percentage of the nut first surface abuts against the body inner surface wherein said body thus reinforces said nut against any radial force. 5. A coupling as in any one of claims 1 to 3 wherein said nut first surface is tapered and converges inwardly so that upon tightening of said nut as the grip-ring moves into said body a percentage of the nut first surface abuts against the body inner surface wherein said body thus reinforces said nut against any radial force. 6. A coupling as any one of claims 1 to 3 wherein said body inner surface is tapered and diverges outwardly of the body, said nut first surface is tapered and converges inwardly wherein upon tightening of said nut the two surfaces abut against each other until in a fixed position at which time the body reinforces the nut against any radial force. 7. A coupling as in claim 6 wherein the taper on the body and the nut is of the same order. 8. A coupling as in any one of the claims 4 to 7 wherein the taper is of the order of two degrees. 9. A coupling as in any one of the above claims wherein said body includes an end adapted to engageably slide into the cavity defined by the nut body and the hooked projection. 10. A coupling as in any one of the above claims wherein said grip-ring includes an outer annular lip extending rearwardly from said second surface, said grip-ring adapted to abut against said body when the nut is in a non-tightened position wherein as the nut is being tightened it is compressed causing the lip to enter into said body, the outer edge of said lip adjacent the body inner surface to provide for support therefor. 11. A coupling as in any one of the above claims wherein the slope of the grip-ring second surface is smaller than the slope of the nut second surface and is selected so that when the nut engages the grip-ring and forces it into the body thereby compressing it, the slope of the grip-ring second surface is generally the same as the nut second surface. 12. A coupling as in claim 11 wherein the slope of the grip-ring second surface in its rest state is some 37 degree , the slope of the nut second surface some 45 degree . 13. A coupling as in any one of the above claims, said nut further including an annular shoulder extending radially inwardly from the edge of said nut second surface, said stop adapted to be abutted by said grip-ring when in its compressed state to thereby provide a resistive force for the grip-ring moving longitudinally out of the body. 14. A coupling as in any one of the above claims wherein the width of said nut second surface is greater than the width of the grip-ring second surface to thereby accommodate said grip-ring second surface sliding alongside said nut second surface as the nut is tightened whilst full surface contact between the two surfaces is maintained. 15. A coupling as in claim 14 wherein the width of said nut second surface is some 1/3 greater than the width of the grip-ring second surface. 16. A coupling as in any one of the above claims wherein said coupling is made from acetal plastics material. 17. A coupling as in any one of claims 2 to 15 wherein said coupling is made from polypropylene material.