GB1591743A

GB1591743A - Pipe couplings

Info

Publication number: GB1591743A
Application number: GB4470077A
Authority: GB
Original assignee: COUPLING SYSTEMS Inc
Current assignee: COUPLING SYSTEMS Inc
Priority date: 1976-11-01
Filing date: 1977-10-27
Publication date: 1981-06-24
Also published as: FR2369495A1; DE2748429A1; AU3011577A; FR2369495B1; CA1069959A

Description

(54) PIPE COUPLINGS (71) We, COUPLING SYSTEMS, Inc., a body corporate organised and existing under the laws of Pennsylvania, United States of America, of 80 Hafner Avenue, Pittsburgh, Pennsylvania 15223, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to pipe couplings and particularly to a connector or coupling adapted to connect metal or plastics pipe or tubing to metal or plastics pipe or tubing to prevent leakage and separation.

There are many connectors or couplings proposed for connecting metal or plastics pipe ends together or for connecting metal to plastics pipe or tubing. One of the most critical areas for such couplings is in the gas industry where even the smallest amount of leakage can lead to serious, if not fatal, consequences. A very serious problem in this area is to provide a coupling which will permit expansion of the pipe being coupled but will prevent separation of the pipe.

The present invention provides a coupling which solves these problems of the prior art, particularly as they have applied to the gas industry, and provides a coupling which can be used to connect metal pipe to plastics pipe, metal pipe to metal pipe or plastics pipe to plastics pipe. It is, in short, adaptable to the materials now used to conduct fluid materials. It will permit the metal pipe ends to expand into the connector but will not permit them to be withdrawn and it will provide a leak proof connection. Another problem which we have discovered is that when plastics pipe, particularly, is being connected in a very high pressure system or where it is under high tensile load, the plastics pipe will flow and permit locking elements or the like to tilt and move out of a sleeve type connector.

The invention provides a coupling for joining the ends of two spaced coaxial pipes, the coupling comprising an elongate sleeve having frustoconical ends opening outwardly and being adapted to receive the two pipe ends, an elastomeric gasket ring associated with each sleeve end, each gasket ring being slidingly engageable on one of the pipe ends and having a frustoconical end portion for fitting the associated sleeve end, a follower member associated with each gasket ring to force it into its associated sleeve end and having an inwardly facing frustoconical opening, locking elements around the pipe ends within the frustoconical openings in the follower members, the radially outermost surfaces of the locking elements bearing against the follower members throughout the axial length of the frustoconical openings therein and the radially innermost surfaces of the locking elements being gripping surfaces extending beyond the frustoconical openings in the follower members in the direction of the pipe ends, and tightening means acting on the follower members to urge the follower members axially together, whereby the gripping surfaces of the locking elements are forced into tight radial engagement witt the exterior of the pipe ends to prevent axial movement of the pipe ends out of the sleeve, and the locking elements coact axially with the gasket rings to force the gasket rings into sealing engagement with the sleeve ends and with sleeve ends and with the pipes.

Preferably the locking elements are connected together by generally resilient means permitting them to form a generally frustoconical ring which can be compressed to smaller diameter to engage the pipes being connected. This may be accomplished by machining a frustoconical ring and slitting it axially to a point adjacent its base to form a plurality of side-by-side jaws, with one slit passing completely through the cone to permit its reduction in diameter. The lock ing elements may also be individually formed and connected together by interme diate rubber bonding members which per mit the jaws to be bent in a circle to form a frustoconical member. Preferably the jaw faces designed to engage the pipe are provided with teeth or knurling to engage the pipe surface. The tightening means between the followers is preferably a plural ity of bolts extending between them through lugs extending radially outwardly from the followers. In a further modification adapted particularly to connect plastics pipe to metal or plastics where the plastics is subject to high pressure or contractive forces, we provide a split metal ring between the locking elements and the pipe and having stop means acting on both the locking elements and the pipe to limit relative movement therebetween.

The invention is illustrated by drawings, of which: Figure I is a section through a connector according to the invention showing a con nection to a metal pipe at one end and a plastics pipe at the other; Figure 2 is an exploded fragmentary view of the right end of the connector of Figure 1 showing the parts involved including one form of the locking elements; Figure 3 illustrates a second embodiment of the locking elements included in a cou pling according to the invention Figure 4 illustrates a third embodiment of the locking elements in which spaced jaws are connected by elastomer connectors in a continuous band from which a suitable length can be cut for use in a coupling according to the invention.

Figure 5 illustrates a fourth embodiment of the locking elements; Figure 6 illustrates another embodiment of the locking elements for use in the elastomer assembly of Figure 4; Figure 7 is a section through still another embodiment of the invention particularly for use where high pressures are exerted on plastics pipe; Figure 8 is an exploded isometric view of the coupling of Figure 7; Figure 9 is an enlarged fragmentary section of the split ring of Figure 7; and Figure 10 is an enlarged fragmentary section of a sccond embodiment of split ring.

Referring to the drawings there is illustrated a metal pipe 10 and a plastics pipe 11 to be connected. A sleeve 12, having a slightly larger internal diameter than the external diameter of pipes 10 and 11, is placed coaxially around the two pipes 10 and 11 to be connected. Each end of sleeve 12 has a flared or frustoconical portion 13 receiving an elastomeric gasket 14 having a cylindrical portion and a frustoconical end portion 14a adapted to fit in the flared end 13 of the sleeve. The elastomeric gasket 14 is adapted to fit snugly around the pipe ends 10 and 11 to be joined. In the case of plastics pipe 11 a support or stiffener sleeve 15 must be inserted into the interior end to be connected. Such sleeves are a well known article of commerce and are generally provided with a radial ring 15a at one end to abut the end of the plastics pipe. An annular cup shaped follower 16 surrounds each pipe 10 and 11, abuts the gasket 14 and is provided with radial lugs 17 having holes 17a receiving bolts 18 with tightening nuts 18a for drawing the followers axially toward the sleeve. Each of the followers 16 has a generally frustoconical opening 16a receiving spaced locking elements 19 either as separate members or preferably connected together in a ring. Each locking element has toothed grooves 20 adapted to engage the surface of pipes 10 and 11. The locking elements 19 may bear against elastomer gasket 14 as shown at the right of Figure 1 or against an intermediate washer 21 as shown at the left of Figure 1. When nuts 18a are tightened on bolts 18 the gaskets 14 are forced into flared ends 13 tightly engaging and sealing the sleeve 12 to the pipe ends 10 and 11. At the same time the locking elements 19 are compressed by the frustoconical opening 16a of follower 16 into tight engagement with the exterior surface of pipes 10 and 11 forcing the toothed grooves 20 into the surface of the pipe to hold it against withdrawal from sleeve 12. Thus the sleeve and pipe ends 10 and 11 are simultaneously sealed by gasket the 14 and held against withdrawal by the locking elements 19 upon tightening of nuts 18a on bolts 18.

In the exploded view, Figure 2, one form of the locking elements 19 is illustrated. In this form a frustoconical metal ring 30 is machined and axial slots 31 are cut from the apex and toward the base but terminate short of the base. A single slot 32 is cut completely through the ring to permit it to be compressed in diameter around pipe 10.

In the form illustrated in Figure 3 locking elements 19a with grooves 20a are connected by elastomer members 40 bonded between each locking element 19a and thus permitting the locking element to be compressed about pipes 10 and 11.

In the form illustrated in Figure 4, locking element 19b provided with knurling 50, are connected by elastomer members 51 bonded to the locking element to form an elongate strip from which a portion may be cut through one of the elastomer members 51 suitable for any given pipe diameter. In the embodiment it is not necessary to carry a plurality of different sizes of locking element rings for different diameters of pipe two be connected because an appropriate length can be cut in the field to suit the particular pipe being joined.

It is, of course, possible to use a plurality of separate locking elements spaced about the pipes to be joined but their application is simplified by joining as described herein.

In the locking element illustrated in Figure 5 a frustoconical metal ring 60 is machined and axial slots 61 are cut from the apex end toward the base but terminate short of the base. A second set of axial slots 62 are cut from the base between slots 61.

This gives the unit more radial compressibility.

In Figure 6 is illustrated a further form of the locking elements in which the base of the element is cut at an angle of about 45".

This reduces the likelihood of the element being tilted as a greater portion of the element extends through the conical openings 16a.

In Figures 7, 8 and 9 there is illustrated another embodiment of the invention particularly adapted to hold plastics pipe under high pressure or extreme tensile forces.

However, this embodiment is adaptable to metal as well as plastics pipe. In this embodiment like parts to those of Figures 1 and 2 bear like numbers with a prime suffix.

In this embodiment a cup shaped follower 70 having a conical flange 71 fits within the axial opening 16' in the follower 16'. The conical flange 71 receives the locking elements 19a' and bears against them over a substantial distance, thus restricting their tipping action if caused to moved axially. A split cylindrical ring 72 surrounds the plastics pipe 11' between it and the elements 19a'. This split ring 72 is provided with a radially outwardly extending stop flange 73 at one end and one or more grooves 74 on opposite sides corresponding to grooves 20a' on the locking elements 19a' which grooves 74 act as stop members holding both the plastics pipe 11' and the locking elements 19a' against relative movement.

The split 75 in ring 72 is preferably at an angle to the two opposite sides as shown in Figure 8.

In Figure 10 is illustrated a second embodiment of split ring 80 with radial outward flanges 81 and 82 at each end receiving between the locking elements 19'. The bottom of ring 80 has grooves 83 engaging the plastics pipe.

WHAT WE CLAIM IS: 1. A coupling for joining the ends of two spaced coaxial pipes, the coupling comprising an elongate sleeve having frustoconical ends opening outwardly and being adapted to receive the two pipe ends, an elastomeric gasket ring associated with each sleeve end, each gasket ring being slidingly engageable on one of the pipe ends and having a frustoconical end portion for fitting the associated sleeve end, a follower member associated with each gasket ring to force it into its associated sleeve end and having an inwardly facing frustoconical opening, locking elements around the pipe ends within the frustoconical openings in the follower members, the radially outcrmost surfaces of the locking elements bcaring against the follower members throughout the axial length of the frustoconical openings therein and the radially innermost surfaces of the locking elements being gripping surfaces extending beyond the frustoconical openings in the follower members in the direction of the pipe ends, and tightening means acting on the follower members to urge the follower members axially together, whereby the gripping surfaces of the locking elements are forced into tight radial engagement with the exterior of the pipe ends to prevent axial movement of the pipe ends out of the sleeve, and the locking elements coact axially with the gasket rings to force the gasket rings into sealing engagement with the sleeve ends and with the pipes.

2. A coupling according to claim 1 wherein the engagement of the locking elements with the exterior of the pipe ends is an indirect engagement through a ring having inner and outer gripping surfaces and an aperture permitting it to be reduced in diameter.

3. A coupling according to claim 1 or claim 2 wherein a floating annular washer having a diameter smaller than the largest diameter of the gasket ring is placed between the gasket ring and the locking elements within the follower member generally to equalize the coacting forces between them.

4. A coupling according to any preceding claim wherein the locking elements are connected together in the form of a ring at least one aperture permitting the ring to be reduced in diameter.

5. A coupling according to claim 4 wherein the locking elements are connected together by elastomeric members.

6. A coupling according to claim 4 wherein the locking elements are in the form of a slotted metal frustoconical ring having a single aperture through the ring to permit reduction of its diameter.

7. A coupling according to any of claims 1 to 5 wherein the gripping surface of each locking element is provided by axially spaced teeth.

8. A coupling according to claim 7 when appended directly or indirectly to claim 2 wherein the outer gripping surface of the ring through which the locking elements grip the exterior of the pipe ends is provided by annular grooves for receiving the teeth.

9. A coupling according to claim 8

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. be connected because an appropriate length can be cut in the field to suit the particular pipe being joined. It is, of course, possible to use a plurality of separate locking elements spaced about the pipes to be joined but their application is simplified by joining as described herein. In the locking element illustrated in Figure 5 a frustoconical metal ring 60 is machined and axial slots 61 are cut from the apex end toward the base but terminate short of the base. A second set of axial slots 62 are cut from the base between slots 61. This gives the unit more radial compressibility. In Figure 6 is illustrated a further form of the locking elements in which the base of the element is cut at an angle of about 45". This reduces the likelihood of the element being tilted as a greater portion of the element extends through the conical openings 16a. In Figures 7, 8 and 9 there is illustrated another embodiment of the invention particularly adapted to hold plastics pipe under high pressure or extreme tensile forces. However, this embodiment is adaptable to metal as well as plastics pipe. In this embodiment like parts to those of Figures 1 and 2 bear like numbers with a prime suffix. In this embodiment a cup shaped follower 70 having a conical flange 71 fits within the axial opening 16' in the follower 16'. The conical flange 71 receives the locking elements 19a' and bears against them over a substantial distance, thus restricting their tipping action if caused to moved axially. A split cylindrical ring 72 surrounds the plastics pipe 11' between it and the elements 19a'. This split ring 72 is provided with a radially outwardly extending stop flange 73 at one end and one or more grooves 74 on opposite sides corresponding to grooves 20a' on the locking elements 19a' which grooves 74 act as stop members holding both the plastics pipe 11' and the locking elements 19a' against relative movement. The split 75 in ring 72 is preferably at an angle to the two opposite sides as shown in Figure 8. In Figure 10 is illustrated a second embodiment of split ring 80 with radial outward flanges 81 and 82 at each end receiving between the locking elements 19'. The bottom of ring 80 has grooves 83 engaging the plastics pipe. WHAT WE CLAIM IS:

1. A coupling for joining the ends of two spaced coaxial pipes, the coupling comprising an elongate sleeve having frustoconical ends opening outwardly and being adapted to receive the two pipe ends, an elastomeric gasket ring associated with each sleeve end, each gasket ring being slidingly engageable on one of the pipe ends and having a frustoconical end portion for fitting the associated sleeve end, a follower member associated with each gasket ring to force it into its associated sleeve end and having an inwardly facing frustoconical opening, locking elements around the pipe ends within the frustoconical openings in the follower members, the radially outcrmost surfaces of the locking elements bcaring against the follower members throughout the axial length of the frustoconical openings therein and the radially innermost surfaces of the locking elements being gripping surfaces extending beyond the frustoconical openings in the follower members in the direction of the pipe ends, and tightening means acting on the follower members to urge the follower members axially together, whereby the gripping surfaces of the locking elements are forced into tight radial engagement with the exterior of the pipe ends to prevent axial movement of the pipe ends out of the sleeve, and the locking elements coact axially with the gasket rings to force the gasket rings into sealing engagement with the sleeve ends and with the pipes.

9. A coupling according to claim 8

wherein the ring through which the locking elements grip the exterior of the pipe ends is provided with an annular radial flange for engaging end ones of the axially spaced teeth of the triangular jaws.

10. A coupling according to any of claims 1 to 5 wherein the gripping surface of each locking element is a knurled surface.

11. A coupling according to claim 2 or according to any of claims 3 to 5 when appended directly or indirectly to claim 2 wherein the gripping surfaces of the locking elements are provided by annular grooves and the ring through which the locking elements grip the exterior of the pipe ends has inner and outer corresponding grooves for engaging the grooves in the locking elements on one side and the exterior surface of the pipe end on the other side.

12. A coupling according to any preceding claim wherein the locking elements are right triangular in cross-section.

13. A coupling according to any of claims 1 to 11 wherein the locking elements are oblique triangular in cross-section.

14. A coupling for joining the ends of two spaced coaxial pipes, the coupling being substantially as herein described with reference to Figures 1 and 2 of the drawings.

15. A coupling according to claim 14 modified as herein described with reference to Figure 3 of the drawings.

16. A coupling according to claim 14 modified as herein described with reference to Figure 4 of the drawings.

17. A coupling according to claim 14 modified as herein described with reference to Figure 5 of the drawings.

18. A coupling according to claim 16 modified as herein described with reference to Figure 6 of the drawings.

19. A coupling for joining the ends of two spaced coaxial pipes, the coupling being substantially as herein described with reference to Figures 7 to 9 of the drawings.

20. A coupling according to claim 19 modified as herein described with reference to Figure 10 of the drawings.