GB2266127A

GB2266127A - Pipe coupling with in situ applied adhesive

Info

Publication number: GB2266127A
Application number: GB9208260A
Authority: GB
Inventors: Robert William Parker
Original assignee: Caradon Terrain Ltd
Current assignee: Polypipe Terrain Ltd
Priority date: 1992-04-14
Filing date: 1992-04-14
Publication date: 1993-10-20
Anticipated expiration: 2012-04-14
Also published as: GB2266127B; GB9208260D0

Abstract

To avoid manual application of adhesive in a pipe coupling comprising a socket (1) there is provided a collar (10) supporting a ring or pod (13) of adhesive encapsulated by a film (14). The arrangement is such that, during insertion of a pipe end (8) into the socket (1), the film (14) is ruptured to release adhesive (13) onto and around the pipe end (8). Preferably, the collar (10) is of resilient or elastomeric material and is loosely retained in its recess with a ring of teeth (11A), whereby insertion of the pipe end (8) causes the collar (10) to extrude the adhesive (13) through the teeth (11A) as circumferentially-spaced ridges, the latter being distributed evenly around the joint upon rotation of the pipe end (8). <IMAGE>

Description

PIPE COUPLINGS This invention relates to pipe couplings more particularly - but not exclusively - for connecting together plastics pipe lengths, said coupling being of the type comprising a socket having a mouth for location of an inserted pipe, said socket and pipe being secured together and sealed via an adhesive which, in the case of plastics, is preferably a mastic or a solvent.

The assembly of such couplings is normally time consuming and cumbersome, involving applying the adhesive manually by smearing it over the pipe end and into the socket before insertion of the components.

Furthermore, in the case of plastics pipes, the mastic or solvent products used can be a health hazard if breathed continually and it is recommended that a mask be used when working with such products.

The object of the present invention is to provide a pipe coupling of the type discussed above in which manual application of the adhesive is avoided.

According to this invention a pipe coupling comprises a socket having a mouth within which an inner annular recess is defined, an annular collar which is dimensioned to be accommodated within said recess, said collar presenting an inward facing surface, and a ring of adhesive which is supported and retained in position on said surface and is encapsulated, the arrangement being such that, during insertion of a pipe end into the socket mouth, the encapsulation is ruptured to release the adhesive onto and around said pipe end.

Preferably, the collar is of a resilient or elastomeric material and is loosely retained in said recess and the inner dimension of the ring of encapsulated adhesive is smaller than the pipe dimension so that after rupture the adhesive is distributed under pressure around the pipe end.

The collar may be curved in cross-section to provide a trailing edge of a similar dimension to the pipe, whereby the pipe end acts during insertion, via said trailing edge and the inward edge of said recess, to cause the curved cross-section of the collar to distort and flatten and provide a distribution pressure across the width of said collar.

Preferably, said socket includes internal stop means to limit the insertion of the pipe end, said stop means being positioned to ensure that the pipe end traverses the ring of adhesive whereby to draw the adhesive deposited thereon further into the socket mouth.

For plastics pipes, the adhesive may be a solvent or a mastic, but in either case, it may be retained on the collar by said encapsulation, which latter also protects the adhesive fróm the atmosphere prior to assembly.

In order that the invention may be readily understood, one preferred embodiment of pipe coupling for plastics drain pipes in accordance therewith will now be described with reference to, and as shown in, the accompanying drawings, in which: Figure 1 is a vertical cross-section through the socket showing the pipe end located in its mouth, and Figure 2 is a similar view in which the pipe end is shown partly inserted in the upper half of the section and fully inserted in the lower half of the section.

Referring to that drawing, the coupling comprises essentially a socket 1 and pipe 2 of circular form, both of an appropriate plastics material such as polypropylene. It will be seen that the socket end 3 is flared to provide a socket mouth 4 which defines an annular recess in the form of a groove 5 along its length. The socket mouth 4 is also stepped at 6 to a smaller diameter to define a bore 7 into which the end 8 of the pipe 2 projects in the fully inserted position, which position is determined by an internal annular stop shoulder 9.

In accordance with the invention, an annular collar 10, preferably of a resilient or elastomeric plastics material such as polypropylene, is dimensioned to be loosely accommodated within said groove 5 and, as shown in Figure 1, it is curved in cross-section and has an angled trailing edge 11 which is serrated to provide a ring of teeth llA projecting inwardly to a diameter smaller than the pipe diameter. The inward facing surface 12 of the collar supports an annular pod, or ring, 13 of an appropriate adhesive, which may be a mastic or a solvent, and it will be noted that the inner diameter of the pod is smaller than the pipe diameter. In either case the adhesive pod adheres to the collar surface and is encapsulated in position by the provision of a thin film 14 of plastics such as polypropylene where the adhesive is a mastic, or a solvent.

For assembly, the pipe end 8 is aligned and located in the socket mouth 4 as shown in Figure 1 and is then progressively pushed axially into the socket mouth (see Figure 2) until it reaches a fully inserted position in contact with the shoulder 9.

During initial movement, the pipe end 8 ruptures the encapsulate film 14 to release the adhesive onto the pipe end around its periphery. Continued movement causes the pipe end to engage the teeth llA of the trailing edge which are forced to rotate outwardly towards the wall of the socket mouth by contact with the inner edge 15 defining the groove 5 as shown in Figure 2. The edge 15 thereby acts as a turning point to distort and flatten the collar 10 over its width as shown, resulting in the adhesive being applied under pressure onto the pipe end. Thereafter, as the pipe end 8 is pushed further into the socket, the adhesive is extruded through the teeth llA of the collar 10 and is drawn into the bore 7 of the socket in the form of a number of axial ridges which are spaced completely around the pipe end. After the pipe end has been fully inserted, to bear against the stop shoulder 9, it is then rotated substantially through 3600 relatively to the socket to distribute the adhesive evenly around the joint thus formed.

Claims

1. A pipe coupling comprising a socket having a mouth within which an inner annular recess is defined, an annular collar which is dimensioned to be accommodated within said recess, said collar presenting an inward facing surface, and a ring of adhesive which is supported and retained in position on said surface and is encapsulated, the arrangement being such that, during insertion of a pipe end into the socket mouth, the encapsulation is ruptured to release the adhesive onto and around said pipe end.

2. A coupling according to claim 1, wherein the collar is of a resilient or elastomeric material and is loosely retained in said recess and the inner dimension of the ring of encapsulated adhesive is smaller than the pipe dimension so that after rupture the adhesive is distributed under pressure around the pipe end.

3. A coupling according to claim 2, wherein said collar is curved in cross-section to provide a trailing edge of a similar dimension to the pipe, whereby, during insertion, the pipe end acts via said trailing edge and the inward edge defining said recess to cause the curved cross-section of the collar to distort and flatten and provide a distribution pressure across the width of said collar.

4. A coupling according to Claim 3, wherein the trailing edge is serrated to provide a ring of teeth which extend to a smaller diameter than the pipe diameter whereby, during insertion of the pipe end, the teeth are distorted outwardly by contact with the pipe end and the adhesive is extruded through said teeth in the form of axial ridges spaced around said pipe end, the pipe being rotatable in the socket after insertion to distribute the ridges of adhesive evenly around the joint thus formed.

5. A coupling according to any one of claims 1 to 4, wherein said socket includes internal stop means to limit the insertion of the pipe end, said stop means being positioned to ensure that the pipe end traverses the ring of adhesive whereby to draw the adhesive deposited thereon into the socket bore.

6. A coupling according to any one of claims 1 to 5, for plastics pipes, wherein the adhesive is a solvent or mastic which is retained on said collar by said encapsulation, which latter also protects the adhesive from the atmosphere prior to assembly.

7. A pipe coupling constructed, arranged and adapted for use substantially as hereinbefore described with reference to and as shown in the accompanying drawings.