GB2376994A

GB2376994A - Pipe coupling

Info

Publication number: GB2376994A
Application number: GB0210227A
Authority: GB
Inventors: Andrew Robert Beever; Keith Millward
Original assignee: Polypipe Building Products Ltd
Current assignee: Polypipe Building Products Ltd
Priority date: 2001-05-04
Filing date: 2002-05-03
Publication date: 2002-12-31
Anticipated expiration: 2022-05-03
Also published as: GB0111030D0; GB2376994B; GB0210227D0

Abstract

A fitting for water supply, comprising a socket for receiving a pipe, the socket having at least one integral reinforcing element.

Description

PIPE COUPLING The invention relates to a fitting, for example a hot water fitting, which comprises a socket for receiving a pipe, especially a pipe coupling.

Such fittings may be made from a relatively flexible material such as polybutylene or PE-X, but the socket then has to be reinforced with a stronger and/or stiffer material. In one known fitting, the socket is reinforced by a threaded end cap made from reinforced nylon that screws onto the end of the socket. In another known fitting, the socket is reinforced by a stainless steel or brass sleeve over the outside of the socket. Both reinforcing elements are relatively expensive, and necessitate additional assembly after manufacture of the socket.

It is therefore an object of the invention to seek to mitigate those disadvantages.

According to a first aspect of the invention there is provided a fitting for water supply, comprising a socket for receiving a pipe, the socket having at least one integral reinforcing element.

As the reinforcing element (s) are integral with the socket, no additional assembly is required after manufacture.

The or each reinforcing element may be positioned on the outer surface of the socket.

The or each reinforcing element may extend over substantially all the outer surface of the socket. The thickness of the socket may then be reduced, resulting in a reduction in costs if the socket is made from an expensive"water quality"plastics

material suitable for contact with drinking water. If the thickness of the socket is reduced, the thickness of the reinforcing element may be increased, which means that the reinforcing element may be made from a less strong and stiff material than is usually required, resulting in a further reduction in costs.

Alternatively, the reinforcing element may extend over part of the outer surface of the socket.

The socket may comprise a seal, and the or one of the reinforcing element (s) may be positioned so as to reinforce the socket in the vicinity of the seal.

The socket may comprise a grip ring, and the or one of the reinforcing element (s) may be positioned so as to reinforce the socket in the vicinity of the grip ring.

The material from which the reinforcing element is made must be strong and/or stiff, and is therefore expensive. The greatest internal stresses in the socket will usually be generated in the vicinity of the seal and the grip ring (where present).

Having reinforcing element (s) in the vicinity of the seal and the grip ring only means that less of the expensive reinforcing element material is required, but reinforcement is still provided where it is most needed.

The socket and the or each reinforcing element may be moulded.

The reinforcing element may be co-moulded with the socket.

The or each reinforcing element may comprise a projection which is accommodated by a corresponding recess in the socket, and which keys the reinforcing element (s) to the socket.

It will be understood too that any suitable co-moulding process may be used, for example, injection moulding.

The or each reinforcing element maybe welded onto the socket.

The or each reinforcing element may be welded onto the socket using an ultrasonic weld.

The or each reinforcing element may be a snap fit on the socket.

The interfaces of the socket and the or each reinforcing element may be tapered to facilitate the snap-fitting of the reinforcing element (s) on the socket.

The socket and the reinforcing element (s) may be made from any suitable comouldable materials, although the reinforcing elements (s) will usually be made from a material which is stronger and/or stiffer than the material from which the socket is made.

The socket and/or the reinforcing element (s) may be made from a plastics material.

According to a second aspect of the invention there is provided a method of making a fitting for a water supply having a socket for receiving a pipe, the socket comprising at least one reinforcing element, wherein the or each reinforcing element is formed integrally with the socket by co-moulding.

Fittings embodying the invention are hereinafter described, by way of example, with reference to the accompanying drawings, in which: Fig. I shows an exploded schematic cross-sectional view of part of a first embodiment of a fitting in the form of a pipe coupling according to the invention; Fig. 2 shows an exploded schematic cross-sectional view of part of a second embodiment of a fitting in the form of a pipe coupling according to the invention; Figs. 3a and 3b show schematic cross-sectional views of part of a third embodiment of a fitting in the form of a pipe coupling according to the invention and an alternative construction of that embodiment; Figs. 4a and 4b show schematic cross-sectional views of part of a fourth embodiment of a fitting in the form of a pipe coupling according to the invention and an alternative construction of that embodiment; and Fig. 5 shows a schematic cross-sectional view of part of a fifth embodiment of a fitting in the form of a pipe coupling according to the invention.

Figs. 1 and 2 each show part of a fitting, in the embodiments a hot water fitting, in the form of a pipe coupling 1 having a socket 2 for receiving a pipe 3, the socket 2 comprising at least one integral reinforcing element 4,5, 6. Figs. 3a, 3b, 4a, 4b and 5 each show part of an alternative embodiment of such a socket 2.

In each of the illustrated embodiments, the socket 2 comprises a hollow body 7 into which the pipe 3 is inserted. The hollow body 7 comprises a first cylindrical

portion 7a and a second cylindrical portion 7b, the first portion 7a having a greater diameter than the second portion 7b.

Inside the first portion 7a of the hollow body 7 is a recess 8 which accommodates, in order from innermost to outermost, an 0-ring seal 9, a washer 10, and a grip ring 11. The grip ring 11 comprises a plurality of flexible teeth 12 which are angled such that they will readily allow insertion of the pipe 3, but will resist removal of that pipe 3. The washer 10 protects the 0-ring seal 9 from being damaged by the grip ring 11.

In the embodiment of Fig. 1, the seal 9, the washer 10 and the grip ring 11 are retained in the recess 8 by two shoulders 13,14, one at either end of the recess 8, and in the embodiment of Fig. 2, the seal 9, the washer 10 and the grip ring 11 are retained in the recess 8 by one shoulder 15 at the innermost end of the recess 8 and a snap-fit end cap 16.

Figs. 1 and 2 are exploded views, it being understood that the interior of the hollow body 7 in use is dimensioned such that the pipe 3 is a close sliding or push

fit in the hollow body 7, the 0-ring seal 9 is in sealing contact with the pipe 3, and the teeth 12 of the grip ring 11 grip the pipe 3.

The embodiment of Fig. 1 comprises a reinforcing element 4 which has been comoulded with the hollow body 7. The reinforcing element 4 is cylindrical, and extends across substantially all of the circumferential outer surface of the first cylindrical portion 7a of the hollow body 7, thereby providing reinforcement in the vicinity of both the 0-ring seal 9 and the grip ring 11 where the greatest internal stresses are generated, while minimising the amount of expensive reinforcing element material required. The reinforcing element 4 comprises a projection 17

which is accommodated by a corresponding recess 18 in the hollow body 7, and which keys the reinforcing element 4 to the hollow body 7.

The embodiment of Fig. 2 comprises two reinforcing elements 5,6 which have been co-moulded with the hollow body 7. Reinforcing element 5 comprises a cylindrical portion 19 and an annular end plate 20, and caps the end of the first cylindrical portion 7a of the hollow body 7, the cylindrical portion 19 extending across the circumferential outer surface of the first portion 7a of the hollow body 7 as far as a position above the grip ring 11, thereby providing reinforcement in the vicinity of the grip ring 11. Reinforcing element 6 is cylindrical, and extends across the portion of the circumferential outer surface of the first portion 7a of the

hollow body that is above the O-ring seal 9, thereby providing reinforcement in the vicinity of the O-ring seal 9. Together, the reinforcing element 5, 6 provide reinforcement in the vicinity of both the O-ring seal 9 and the grip ring 11 where the greatest internal stresses are generated, while minimising the amount of expensive reinforcing element material required.

The reinforcing elements 4,5, 6 are made from a high cost, high strength plastics material such as reinforced nylon. The hollow body 7 is made from a low cost, low strength plastics material such as polybutylene or PE-X.

The reinforcing elements 4,5, 6 of Figs. 1 and 2 and the hollow body 7 are comoulded together using an injection moulding machine with two barrels containing the two different plastics materials. The moulds may comprise either sleeves which move back to create an additional cavity recess for the second material after the first material is injected, or rotary moulds which use common cores but move the moulding and core into a second cavity which includes recesses for the additional parts of the moulding.

The embodiment of Fig. 3a comprises a reinforcing element 21, which is substantially similar to the reinforcing element 5 shown in Fig. 2 except that it extends across substantially all of the circumferential outer-surface of the first cylindrical portion 7a of the hollow body 7, and is welded to the hollow body 7, not co-moulded with the hollow body 7. The reinforcing element 21 and the hollow body 7 are welded over the whole of their contacting surfaces. This may be done by, for example, pin welding or socket fusion welding.

Fig. 3b shows an alternative construction of the embodiment of Fig. 3a, in which the reinforcing element 21 and the hollow body 7 are welded together by a localised weld using an ultrasonic weld energy director 22. Circumferential stiffness will still be provided.

The embodiment of Fig. 4a comprises a reinforcing element 23, which is similar to the reinforcing element 21 shown in Fig. 3a, except that it is snap-fitted on to the hollow body 7, not welded on to the hollow body 7. The reinforcing element 23 comprises a flange 24 at the free end of the cylindrical portion 25 of the reinforcing element 24 in order to allow the reinforcing element 23 to be snapfitted over the first cylindrical portion 7a of the hollow body 7.

Fig. 4b shows an alternative construction of the embodiment of Fig. 4b, in which the inner surface of the reinforcing element 23 and the outer surface of the hollow body 7 are tapered to facilitate the snap-fitting of the reinforcing element 23 on the hollow body 7.

The embodiment of Fig. 5 comprises a reinforcing element 26, which, unlike the reinforcing elements of Figs. 1 to 4, extends over all of the outer surface of the

hollow body 7. The reinforcing element 26 is thicker, and the hollow body 7 is thinner than in the embodiments of Figs. 1 to 4. The reinforcing element 26 has been co-moulded with the hollow body 7 as in the embodiments of Figs. 1 and 2. Such an arrangement is useful where the fitting is to be used as part of a drinking water supply as it means that a smaller quality of expensive"water quality" plastics material is required for the hollow body 7. It also means that the reinforcing element 26 may be made from a less strong and stiff material than is usually required, resulting in a further reduction in costs.

Claims

CLAIMS: 1. A fitting for water supply, comprising a socket for receiving a pipe, the socket having at least one integral reinforcing element.
2. A fitting according to claim 1, wherein the or each reinforcing element is positioned on the outer surface of the socket.
3. A fitting according to claim 2, wherein the or each reinforcing element extends over substantially all the outer surface of the socket.
4. A fitting according to claim 2, wherein the or each reinforcing element extends over part of the outer surface of the socket.
5. A fitting according to any preceding claim, wherein the socket comprises a seal, and the or one of the reinforcing element (s) is positioned so as to reinforce the socket.
6. A fitting according to any preceding claim, wherein the socket comprises a grip ring, and the or one of the reinforcing element (s) is positioned so as to reinforce the socket in the vicinity of the grip ring.
7. A fitting according to any preceding claim, wherein the socket and the or each reinforcing element are moulded.
8. A fitting according to claim 7, the reinforcing element being co-moulded with the socket.

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9. A fitting according to claim 7 or claim 8, wherein the or each reinforcing element comprises a projection which is accommodated by a corresponding recess in the socket, and which keys the reinforcing element (s) to the socket.
10. A fitting according to any of claims 1 to 6, wherein the or each reinforcing element is welded onto the socket.
11. A fitting according to claim 10, wherein the or each reinforcing element is welded onto the socket using an ultrasonic weld.
12. A fitting according to any of claims 1 to 6, wherein the or each reinforcing element is a snap-fit on the socket.
13. A fitting according to claim 12, wherein the interfaces of the socket and the or each reinforcing element are tapered to facilitate the snap-fitting of the reinforcing element (s) on the socket.
14. A fitting according to any preceding claim, wherein the socket and/or the reinforcing element (s) are made from a plastics material.
15. A fitting, substantially as described herein with reference to the drawings.
16. A fitting according to any preceding claim, comprising a pipe coupling.

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17. A method of making a fitting for water supply having a socket for receiving a pipe, the socket comprising at least one reinforcing element, wherein the or each reinforcing element is formed integrally with the socket by co- moulding.