GB2197410A

GB2197410A - Pipe coupling

Info

Publication number: GB2197410A
Application number: GB08723904A
Authority: GB
Inventors: John Edward Rowse
Original assignee: Samuel Booth & Co Ltd
Current assignee: Samuel Booth & Co Ltd
Priority date: 1986-10-11
Filing date: 1987-10-12
Publication date: 1988-05-18
Also published as: GB8723904D0

Abstract

Coupling member 17 releasably connected by screw thread 15 to body 12, houses a pipe gripping member 25 adapted to receive the pipe 30 in gripping relationship therewith, the coupling and pipe gripping members having cooperating surfaces 20 whereby, in use, the pipe gripping member is urged into gripping relationship with the pipe to couple the pipe to the coupling member and hence to the body. Sealing means 35 provides a fluid tight seal between the pipe and the body. <IMAGE>

Description

SPECIFICATION Pipe coupling This invention relates to a pipe coupling.

According to the invention we provide a pipe coupling comprising a body to which a pipe is to be coupled, a coupling member releasably connected to the body and housing a pipe gripping member adapted to receive the pipe in gripping relationship therewith, the coupling and pipe gripping members having co-operating surfaces whereby, in use, the pipe gripping member is urged into gripping relationship with the pipe to couple the pipe to the coupling member and hence to the body and there being sealing means to provide a fluid tight seal between the pipe and the body.

The sealing means may comprise a ring shaped sealing member disposed between and in sealing engagement with the pipe and the coupling member.

The sealing means may also comprise sealing engagement between the sealing member and the body.

Alternatively the sealing means may also comprise a further sealing member between the body and the coupling member.

The gripping member may be capable of limited movement outwardly of the coupling relative to the coupling member, for example when a withdrawing force is applied to the pipe, to cause the gripping member to be urged into said gripping relationship with the pipe.

The sealing member may be located relative to the coupling member so as to maintain a fluid tight seal with the body independently of said movement of the gripping member.

The co-operating surfaces may comprise an internal surface of frusto-conical configuration on the coupling member and an external surface of co-operating configuration provided on the gripping member, the diameters of the surfaces decreasing in a direction outwardly of the coupling.

The gripping member may be provided with at least one tooth to engage the pipe.

Preferably the or each tooth extends circumferentially internally of the gripping member and has a flank which faces inwardly of the coupling which extends normal or substantially normal to the longitudinal axis of the coupling member whilst the other, outwardly facing, flank is inclined radially and longitudinally outwardly of the coupling. This configuration facilitates introduction of a pipe into the coupling since the pipe is pushed in a direction so that the outwardly facing flanks engage the end of the pipe and, because of their inclination, facilitate introduction of the pipe whilst withdrawal of the pipe in the opposite direction is resisted due to the engagement of the pipe by the inwardly facing flanks.

The gripping member is preferably of annular configuration in cross-section but with a radially extending slot so that the gripping member may expand radially on introduction of the pipe and then be compressed in to gripping engagement with the pipe by said cooperating surfaces when a withdrawing force is applied to the pipe.

The coupling member may be provided with an inwardly facing abutment surface which engages a spacer disposed between the sealing ring and the abutment surface. The spacer limits movement of the sealing ring in a direction outwardly of the coupling and the sealing ring is in sealing engagement with the body as well as with the pipe and coupling member independent of any movement of the gripping member by said withdrawing force.

The sealing ring may be engaged with a portion of the coupling member which is of cylindrical configuration and the abutment surface is provided between the cylindrical surface and the hereinbefore mentioned frustoconical surface.

An example of the invention will now be described by way of example with reference to the accompanying drawings which is a cross-sectional view through a stopcock provided with a pipe coupling embodying the invention.

Referring to the drawings, a stopcock 10 is provided with a pipe coupling 11 a, 11 b at opposite ends. In the present example only the pipe coupling 1 lea is fully illustrated and is in accordance with the present invention. The pipe coupling 11 b is preferably also a coupling embodying the invention but may be any other type of coupling. The pipe coupling 1 lea comprises a body 12 which, in the present example is formed to provide the body of the stopcock 10. It should however be appreciated that, if desired, the body 12 may be of any desired configuration for example it may comprise a straight, reduced, tee, or elbow coupling.

The body 12 has a passage 13 having at its outer end a larger diameter portion 14 with a shoulder 12a therebetween. Threadedly engaged with an internal screw thread 15 of the portion 14 is an external screw thread 16 provided on a pipe coupling member 17.

The pipe coupling member 17 has a conventional hexagon formation 18 at its outer end for engagement with a spanner for tightening of the pipe coupling in to the body. The remainder of the external configuration of pipe coupling member 17 is generally cylindrical as indicated at 19 except, of course, for the screw thread 16 formed thereon. The internal configuration of the pipe coupling member 17 comprises a frusto-conical portion 20 separated by a shoulder 21 from a cylindrical portion 22.

Housed within the pipe coupling member 17 is a pipe gripping member 25 having an exter nal configuration which is frusto-conical to provide a surface 26 which co-operates with the surface of the frusto-conical part 20 of the coupling member 17. If desired only one of the surfaces 20 and 26 may be frusto-conical or otherwise tapered, indeed, the co-operating surfaces may be of any desired configuration to urge the pipe gripping member into gripping relationship with the pipe.

The internal surface of the pipe gripping member 25 is generally cylindrical as shown at 27 but is provided with five circumferentially extending teeth 28 the inwardly facing flanks 29 of which extend normal to the longitudinal axis X-X of the coupling whilst the outwardly facing flanks 29a are inclined radially and longitudinally outwardly so as to be inclined to the axis X-X at an angle of approximately 240.

In transverse cross-section the gripping member 25 is annular except for a radially and longitudinally extending slot which permits of the gripping member 25 expanding radially on insertion of a pipe 30 to be coupled to the body 12 followed by contraction when a withdrawal force is applied to the pipe so that the co-operating frusto-conical surfaces 20, 26 urge the gripping member 25 further into engagement with the pipe 30 so that the teeth 28 are pressed in to the surface of the pipe 30. The pipe 30 is made of a conventional synthetic plastics such as medium density polyethylene material and a copper insert 31 is engaged in the end of the pipe prior to assembly of the coupling so as to strengthen the end of the pipe.

A sealing ring 35 of 0 configuration is received within the cylindrical parts 22 of the coupling member and is positioned between and in sealing engagement with the part 22 and the pipe 30. A spacer member 36 is engaged with the shoulder 21 and serves to maintain the 0 ring 30 in sealing engagement with the shoulder 12a between the parts 13 and 14 independently of movement of the gripping member 25 from the pipe insertion position shown in dotted line to its pipe gripping line shown in full line.

The spacer 36 is of annular configuration in end view and is preferably made of gun metal as are the body 12 and coupling member 17.

The gripping member is made of a suitable hard synthetic plastics material such as acrylonitryl butadiene styrene whilst the 0 ring is made of a suitable conventional material such as neoprene.

The pipe coupling of the present invention permits of easy assembly of a pipe to the body 12 simply by pushing the pipe 30, with the insert 31 previously engaged therewithin, into the gripping member until the end of the pipe is fully home i.e. engaged with a shoulder 13a at the inner end of the part 13 of the body 12. Withdrawl of the pipe 30 is prevented by the teeth 28 being pressed into the pipe as explained hereinbefore. The releasable connection of the coupling member 17 to the body 12 facilitates removal of the pipe and/or replacement of the 0 ring. In addition it permits the body to be provided, at will, with a coupling according to the present invention or a coupling of any other desired type since the screw thread 15 is of a standard size to receive suitable conventional male members.For example, engaged with the thread 15 may be an adaptor to connect to a female iron B.S.P.

thread.

In a modification the distance between the shoulder 12a and the spacer member 36 may be such that the 0 ring 30 is not in sealing engagement with the shoulder 12a. In this case a further sealing means is provided between the body and the coupling member 17.

This may be a sealing ring engaged between the shoulder 12a and the opposed surface 17a of the coupling member or a means, such as PTFE tape, to render the screw threaded connection between the coupling member 17 and the body 12 fluid tight.

Figure 2 illustrates a further modification. In Fig. 2 the same reference numerals are used for corresponding parts as are used in Fig. 1 and the pipe coupling of the modification is the same as the pipe coupling illustrated in Fig. 1 except as hereinafter identified. The pipe coupling of Fig. 2 differs from that of Fig. 1 by complete omission of the spacer member 36. Consequently, the pipe coupling member 17 has an internal surface 26 which is frusto-conical as shown at 20, over substantially the whole of the extent of the member 17, there being a short cylindrical portion 40 at the inner end of the coupling member 17. In addition, at this inner end the coupling member is provided with an external chamfer 41 for engagement with an 0 ring 42 which is compressed by the chamfer 41 into the corner between the shoulder 12a and an unthreaded part 14a of the larger diameter portion 14. The 0 ring 42 comprises a further sealing member which provides a seal between the body 12 and coupling member 17.

The features disclosed in the foregoing description, or the accompanying drawing, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A pipe coupling comprising a body to which a pipe is to be coupled, a coupling member releasably connected to the body and housing a pipe gripping member adapted to receive the pipe in gripping relationship therewith, the coupling and pipe gripping members having co-operating surfaces whereby, in use, the pipe gripping member is urged into gripping relationship with the pipe to couple the pipe to the coupling member and hence to the body and there being sealing means to provide a fluid tight seal between the pipe and the body.

2. A pipe coupling according to Claim 1 wherein the sealing means comprises a ring shaped sealing member disposed between and in sealing engagement with the pipe and the coupling member.

3. A pipe coupling according to Claim 2 wherein the sealing means also comprises sealing engagement between the sealing member and the body.

4. A pipe coupling according to Claim 2 wherein the sealing means also comprises a further sealing member between the body and the coupling member.

5. A pipe coupling according to Claim 4 wherein the further seal member comprises a ring shaped sealing member disposed between an inner end part of the coupling member and an outwardly facing abutment surface of the body.

6. A pipe coupling according to any one of the preceding claims wherein the gripping member is capable of limited movement outwardly of the coupling relative to the coupling member, when a withdrawing force is applied to the pipe, to cause the gripping member to be urged into said gripping relationship with the pipe.

7. A pipe coupling according to Claim 6 wherein the sealing member is located relative to the coupling member so as to maintain a fluid tight seal with the body independently of said movement of the gripping member.

8. A pipe coupling according to any one of the preceding claims wherein the co-operating surfaces comprise an internal surface of frusto-conical configuration on the coupling member and an external surface of co-operating configuration provided on the gripping member, the diameters of the surfaces decreasing in a direction outwardly of the coupling.

9. A pipe coupling according to any one of the preceding claims wherein the gripping member is provided with at least one tooth to engage the pipe.

10. A pipe coupling according to Claim 9 wherein the or each tooth extends circumferentially internally of the gripping member and has a flank which faces inwardly of the coupling which extends normal or substantially normal to the longitudinal axis of the coupling member whilst the other, outwardly facing flank is inclined radially and longitudinally outwardly of the coupling.

11. A pipe coupling according to any one of the preceding claims wherein the gripping member is of annular configuration in crosssection but with a radially extending slot so that the gripping member may expand radially on introduction of the pipe and then be compressed in to gripping engagement with the pipe by said co-operating surfaces when a withdrawing force is applied to the pipe.

12. A pipe coupling according to any one of the preceding claims wherein the coupling member is provided with an inwardly facing abutment surface which engages a spacer disposed between the sealing ring and the abutment surface.

13. A pipe coupling according to Claim 12 wherein the sealing ring is engaged with a portion of the coupling member which is of cylindrical configuration and the abutment surface is provided between the cylindrical surface and the hereinbefore mentioned frustoconical surface.

14. A pipe coupling substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

15. A pipe coupling substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

16. A stopcock incorporating a pipe coupling according to any one of the preceding claims.

17. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.