GB2164112A

GB2164112A - Pipe coupling

Info

Publication number: GB2164112A
Application number: GB08521990A
Authority: GB
Inventors: David John Wall; David John Hill
Original assignee: Victaulic Co PLC
Current assignee: Victaulic Co PLC
Priority date: 1984-09-06
Filing date: 1985-09-04
Publication date: 1986-03-12
Also published as: GB8521990D0; GB2164112B; GB8422573D0

Abstract

A pipe coupling comprises an unitary annular sleeve member 6 formed from metal having at least one open end; shoulders 8,9 located within the sleeve member directed axially towards the open end thereof; annular grip members 10 located within the sleeve member against the shoulder, the grip member having teeth which, in an unstressed condition extend and project radially inwardly of the shoulder within the sleeve member and are inclined axially inwardly of the sleeve member. Elastomeric sealing rings 12 are located within the sleeve member axially outwardly of the grip member and separated therefrom by means of annular disc washers 11; the open end(s) of the annular sleeve member being turned radially inwardly so as to hold the elastomeric sealing ring within the sleeve member. <IMAGE>

Description

SPECIFICATION Improvements in or relating to pipe couplings and pipe joints formed therewith This invention relates to pipe couplings and pipe joints formed therewith. More particularly the invention relates to such couplings and joints for connecting pipes of plastics or soft metal.

It is to be understood that by the word "pipe" as used herein is included any pipe-like member such as pipe, tube and hose, and hollow pipe fittings used in pipework such as elbows, "T" junctions, end member and valves for example. Similarly the expression "pipe couplings" includes hollow pipe fittings such as elbows and "T" junctions when adapted to serve as couplings.

It is also to be understood that by the expression "soft metal" as used herein, is meant that class of easily workable metals and metal alloys of which copper is a prime and typical example.

It has been proposed to form such couplings with a sleeve like body portion formed form a metal such as copper and an annular sealing member located within the body member at each end thereof for providing a seal with the pipes to be connected, and an annular spring metal grab ring within the sleevelike member adjacent each end thereof having radially and axially inwardly extending teeth arranged to bite into the external periphery of the pipe to be coupled and inhibit removal once inserted into the sleevelike member.

It is an object of the present invention to enable the provision of couplings of this kind of compact construction, simple assembly and robust and effective operation, together with joints formed therewith.

According to the invention there is provided a pipe coupling comprising a unitary annular sleeve member formed from metal having at least one open end; a shoulder located within the sleeve member directed axially towards the open end thereof; an annular grip member located within the sleeve member against the shoulder, the grip member having teeth which, in an unstressed condition extend and project radially inwardly of the shoulder within the sleeve member and are inclined axially inwardly of the sleeve member; an elastomeric sealing ring located within the sleeve member axially outwardly of the grip member and separated therefrom by means of an annular disc washer; the open end of the annular sleeve member being turned radially inwardly so as to hold the elastomeric sealing ring within the sleeve member.

The shoulder may be provided by a radially inwardly directed portion of the sleeve member or alternatively may be provided by an annular insert member disposed within the sleeve member.

The annular sleeve member may be provided with a reduced diameter portion associated with the provision of the shoulder. If an insert member is utilised this may be provided with a corresponding reduced diameter outer surface whereby the insert is held in positive location within the sleeve member thereby.

The sleeve member may be double ended and may be provided with a single central insert member (which may be split into two halves in a plane normal to its axis through its centre) having a shoulder on each axial side thereof, and a grip member, spacing washer, and elastomeric sealing ring, located axially outwardly from the insert member to each end of the sleeve member. Both ends of the sleeve are turned in to retain the elastomeric sealing ring. A centrally located internally protruding rib may be provided in the insert member for positive location of pipe ends within the coupling.

The elastomeric sealing ring may be in the form of an "0" ring and may be of circular or oval cross section or other convenient section.

Standard insertion members may be utilised with pipe couplings other than straight through pipe couplings. Thus where an elbow or a T" junction is used as a coupling and is provided with a reduced diameter portion away from its open ends (as is common with such metal pipework members) a "standard" pipe insert having a reduced outer diameter portion can be used. Such a "standard" insert may comprise one split half of the insert member of a straight through coupling. By abutting against the reduced diameter portion of the elbow or "T" junction the "standard" insert is positively located within and provides the necessary shoulder for the grab ring abuttment adjacent one end of the elbow or "T" junction as the case may be.Thus the insert shape is made such as to rest against and be held by the reduced diameter portion of the elbow or "T" junction. Such use of a "standard" insert results in a considerable economic saving both in terms of production costs and in terms of stock-holdings with regard to the inserts.

The sleevelike member may be formed of a seamless, for example extruded, tube of metal such as copper, copper alloy, stainless steel or aluminium. The configuration where a reduced diameter portion is provided may be achieved by spinning the sleeve in known manner within an external die of appropriate inside shape or by pressing the sleeve in known manner on an appropriately shaped internal mandrel, which may be the insert member.

We have found that by means of the present invention, particularly the provision of the sleeve of soft metal, we can provide a coupling which is exceptionally simple to manufacture and assemble and exceptionally simple and convenient to use and with which to form pipe joints.

The invention includes within its scope a pipe joint utilising a coupling as herein defined and described.

In order that the invention may be more readily understood, four embodiments thereof will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a sectional elevational of one form of joint incorporating a coupling in accordance with the invention; Figure 2 is a sectional elevation of a second form of joint incorporating a coupling in accordance with the invention; Figure 3 is a sectional elevation of a third form of a joint incorporating a coupling in accordance with the invention; and Figure 4 is a sectional elevation of a fourth form of a joint incorporating a coupling in accordance with the invention.

Referring now to Fig. 1 there will be seen a joint intended for use with, for example, a hot water pipework system and linking two pipes 1, 2 of cross linked polyethylene. The pipes may each be provided with an internal metal ferrule 3, 4 adjacent each end to provide greater rigidity thereto within the coupling.

The coupling 5 essentially comprises a seamless soft metal sleeve 6 within which is centrally located an annular insert member 7 of plastics such as injection moulded polypropylene or acetal. The insert at each end provides shoulders 8, 9 abutting against which are grab rings 10 formed of plastic or metal such as stainless steel spring material having radially and axially inwardly extending and projecting teeth.

The grab rings are located on their axially outer sides by annular disc washers 11 of plastic or metal, on the sides of which towards the open ends of the sleeves are located rubber sealing "0" rings 12. The "O" rings are held in place by the end portion 13 of the open ends of the sleeve members 6 being turned radially inwardly.

Construction of the coupling is achieved by fitting the annular insert 7 within the sleeve, and then providing on each side thereof the grab rings 10, the separating disc washers 11, and the "0" rings 12. Thereafter the two ends 13 of the sleeve are turned over to form the completed coupling. As can be appreciated such a formation is simple, effective and inexpensive.

Formation of a joint is obtained by inserting the ends of the pipes 1 and 2 (to which the internal ferrules 3 and 5 have been fitted) into the open ends of the sleeve 6. As can be seen the pipes are a sliding fit within the sleeve insert 7. The ends of the pipes locate against an internal rib 14 of the annular insert 7. As each pipe is fitted into the sleeve, the associated sealing member 12 is deformed and compressed so as to provide the required sealing effect. The teeth of the grab ring 10 are then deflected axially inwardly of the sleeve member (i.e. in the direction of their original inclination) by the passage of the pipe.

Any subsequent attempt to remove the pipe will tend to straighten the deflected teeth of the grab ring 10 which will therefore bite into the pipe and resist outward movement thereof.

The arrangement of Fig. 2 is very similar to that of the Fig. 1 and its operation almost identical. However, in this case the annular insert member 15 is positively located within the sleeve. Thus a reduced diameter central position 16 of the sleeve 6 mates with a portion 17 of the insert 15 having a reduced external diameter. Such a reduction of the diameter of the sleeve may be formed after insertion of the insert. Alternatively, the insert member can be in two annular halves connecting together at the centre line of the coupling, each being then capable of insertion, one from each end of the sleeve (prior to the turning over of the ends of the sleeve) to engage upon the reduced diameter portion 16 of the sleeve member 6. In this case identical insert members can be used with coupling assemblies for elbows or "T" junctions having reduced diameter portions.

Such an arrangement is ilustrated in Fig. 3.

In that figure, the two pipes 1 and 2 are to be connected at right angles and are joined by means of an elbow fitting 18 having a reduced diameter portion 19. The pipes 1 and 2 are provided with stiffening internal ferrules 3 and 4. Annular insert members 20 and 21 are provided within the ends of the elbow and are located upon the reduced diameter portion. It is to be observed that each insert member is essentially the same as half of the insert member 15 of the coupling illustrated in Fig.

2.

The inserts provide internal shoulders for grab rings 10, which are separated from "0" rings 12 by annular disc washers 11, the ends 22, 23 of the elbow being turned over to form the completed coupling.

The arrangement of Fig. 4 is very similar to that of Fig. 2 and its operation almost identical. However in this case the insert member is omitted, and instead the central portion 25 of the sleeve 6 is heavily reduced in diameter with sharply angled sides 26 to the reduction and has an internal diameter equivalent to that of the insert member of other embodiments whereby to constitute a radially inwardly directed portion of the sleeve 6 providing shoulders against which the grab rings 10 abut. An internal rib 27 is provided around the reduced diameter central portion 25 against which the ends of the pipes 1 and 2 locate.

The joint formation and operation of the embodiments illustrated in Fig. 2, Fig. 3 and Fig. 4, are in essence very similar to that illustrated in Fig. 1.

The coupling and joint of the present invention has a number of advantageous features.

Thus the sleeve member may be formed from metal tube from stock, or may utilise commercially available hollow fitting components for pipework either in their existing form or slightly modified. Appropriate components are currently available in copper and stainless steel. Yet again, the construction of the coupling is such that it has very small external dimensions for a push-grip fitting. Thus for example a coupling for connecting 15mm pipe is of similar magnitude to standard 22mm copper capillary soldered fittings for such pipe, and much smaller than previously proposed mechanical or push fittings. Yet again the use of a plastic insert to locate a pipe accurately within the fitting and providing the necessary spacing and locating means for the grab ring, washer, and rubber "0" ring enables the provision of a most effective coupling and joint.

Claims

1. A pipe coupling comprising a unitary annular sleeve member formed from metal having at least one open end; a shoulder located within the sleeve member directed axially towards the open end thereof; an annular grip member located within the sleeve member against the shoulder, the grip member having teeth which, in an unstressed condition extend and project radially inwardly of the shoulder within the sleeve member and are inclined axially inwardly of the sleeve member; an elastomeric sealing ring located within the sleeve member axially outwardly of the grip member and separated therefrom by means of an annular disc washer; the open end of the annular sleeve member being turned radially inwardly so as to hold the elastomeric sealing ring within the sleeve member.

2. A pipe coupling according to Claim 1 wherein the shoulder is provided by a radially inwardly directed portion of the sleeve member.

3. A pipe coupling according to Claim 1 wherein the shoulder is provided by an annular insert member disposed within the sleeve member.

4. A pipe coupling according to any one of the preceding claim wherein the sleeve member is provided with a reduced diameter portion associated with the provision of the shoulder.

5. A pipe coupling according to Claim 4 as dependent on Claim 3 wherein the insert member is provided with a reduced diameter outer surface corresponding to reduced diameter portion of the sleeve member whereby the insert is held in position location within the sleeve member.

6. A pipe coupling according to any one of the preceding claims wherein the sleeve member is double ended and has duplication therein of the shoulder, the grip member, the disc washer and the sealing ring with respect to each end, both ends being inwardly turned to retain the sealing rings.

7. A pipe coupling according to Claim 6 wherein an internally protruding rib is provided axially centrally within the sleeve member for positive location of pipe ends therewithin.

8. A pipe couple according to Claim 6 or 7 as dependent on Claim 3 or 5 wherein the sleeve member is provided with a single central insert member having a shoulder on each axial side thereof.

9. A pipe coupling according to Claim 8 wherein the insert member is split into two halves transverse to its axis.

10. A pipe coupling according to Claim 8 or 9 wherein an axially centrally located internally protruding rib is provided on the insert member for positive location of pipe ends within the coupling.

11. A pipe coupling substantially as shown in and as hereinbefore described with reference to Figs. 1, 2, 3 or 4 of the accompanying drawings.

12. A joint between pipes incorporating a pipe coupling according to any one of the preceding claims.