GB2178501A

GB2178501A - Pipe couplings

Info

Publication number: GB2178501A
Application number: GB08519009A
Authority: GB
Inventors: Derrick Papworth
Original assignee: Victaulic Co PLC
Current assignee: Victaulic Co PLC
Priority date: 1985-07-27
Filing date: 1985-07-27
Publication date: 1987-02-11
Also published as: GB8519009D0; GB2178501B

Abstract

The invention provides a pipe coupling 5 including a unitary annular sleeve member 6 formed from plastics material having at least one open end; an internal annular shoulder 9 formed integrally within the sleeve member 6; an annular grip member 10 located within the sleeve 6 having teeth which, in an unstressed condition, extend and project radially inwardly of the internal wall of the sleeve member and are inclined axially inwardly of the sleeve member 6, the grip member 10 abutting within the sleeve member 6 against the internal shoulder 9; an elastomeric sealing ring 12 located within the sleeve member 6 axially outwardly of the grip member 10 and separated therefrom by means of an annular disc washer 11; and a locating member 14 engaging in at least one slot 15 in the sleeve member 6 opening at least partially within the sleeve member 6 adjacent the open end thereof so that the locating member 14 locates the sealing ring 12 within the sleeve member 6. <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 in any pipelike member such as pipe tube and hose, and hollow pipe fittings used in pipework such as elbows, "T" junctions, end members and valves for example. Similarly the expression "pipe couplings" includes hollow pipe fittings such as elbows and "T" junctions where adapted to serve couplings. It is also understood that 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 cylindrical body member formed from a thermoplastic material, an annular sealing member at each end of the body member for providing a seal with the pipes to be connected, and an annular spring metal grab ring adjacent each end of the body member and having radially inwardly extending teeth arranged to bite into the external periphery of the pipe and inhibit its removal from the body member once inserted.

It is an object of the present invention to enable the provision of such a pipe coupling 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 including a unitary annular sleeve member formed from plastics material having at least one open end; an internal annular shoulder formed integrally within the sleeve member; an annular grip member located within the sleeve having teeth which, in an unstressed condition, extend and project radially inwardly of the internal wall of the sleeve mamber and are inclined axially inwardly of the sleeve member, the grip member abutting within the sleeve member against the internal shoulder; 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; and a locating member engaging in at least one slot in the sleeve member opening at least partially within the sleeve member adjacent the open end thereof so that the locating member locates the sealing ring within the sleeve member.

The locating member may comprise a spring member engaging in at least one slot in the outer wall of the sleeve member, the slot or slots having a plurality of openings into the inside of the sleeve member through which the locating member extends to locate the sealing ring within the sleeve member.

Alternatively, the locating member may be an annular member disposed in an annular groove extending around the inner wall of the sleeve number adjacent the open end thereof and locating the sealing ring within the sleeve member.

The locating member may comprise a split circlip of disc like configuration or may be a retaining ring capable of snap fitting within the circumferential inner annular groove. The locating member may be provided on its axially inner side with an annular disc against which the sealing ring abuts so as to provide a more satisfactory surface for contact with the sealing member that can at times be provided by a split ring circlip, for example.

The sleeve member may be double ended and may be provided with grab ring, washers, elastomeric sealing rings, and retaining rings located within internal annular grooves, at both ends thereof. The integral internal shoulder in this case may comprise a central portion of the sleeve member of lesser internal diameter. A central located internally protruding ring may be provided around the sleeve member for positive location of pipe ends within the coupling.

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

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, one embodiment thereof will now be described by way of example with reference to the accompanying drawing which is a sectional elevation of a joint incorporating a coupling in accordance with the invention.

The joint shown in the figure is intended for use with, for example, a hot water pipework system and includes two pipes 1, 2 of cross linked polyethylene.

The pipes are each provided with internal metal ferrules 3,4 adjacent their ends to provide greater rigidity thereto within the coupling 5.

The coupling 5 essentially comprises a unitary moulding of cross kinked polyethylene constituting a sleeve member 6. This has a central portion 7 of reduced internal diameter, and a corresponding central outer portion 8 of reduced external diameter. Located within the sleeve member 6 on each side of the inter nally reduced portion and abutting a shoulder 9 provided thereby is a grab ring 10 formed of plastic or metal such as stainless steel spring material having radially and axially inwardly extending teeth with respect to the sleeve member 6.

The grab rings 10 are held in place by an nular washers 11, on the outer side of which (towards the open ends of the sleeve) are located rubber sealing "0" rings 12. A further washer 13 is provided outside each of the "0" rings 12 in the direction of the sleeve opening, and these washers are held in place by means of split circlips 14 of plastic or metal sprung into annular grooves 15 in the internal wall of the sleeve member, the circlips being formed of plastic or of metal. The washers 11 and 13 likewise be formed of plastic or metal. A rib 16 locates pipes 1, 2 within the coupling.

Assembly of the coupling is achieved by fitting the grab rings 10, washers 11, "0" rings 12 and second washers 13 into each end of the sleeve member and then inserting the split circlips 14 into the annular grooves 15 in the internal wall of the sleeve member 6.

Formation of the joint is obtained by inserting ends of the pipes 12 and 2, to which the internal ferrules 3 and 4 have been fitted, into the open ends of the sleeve 6. As can be seen, the pipes are sliding fits within the central portion 7 of the sleeve. As the pipes are fitted into the sleeve, the sealing rings 2 are deformed and compressed so as to provide the required sealing effect. The teeth of the grab rings 10 are then deflected axially inwards of the sleeve member (i.e. the direction of their original inclination) by the passage of the pipe. Any subsequent attempt to remove the pipes will tend to straighten the deflected teeth of the grab rings which will therefore bite into the pipes and resist outward movement thereof.However the joint may be disconnectable by removing one or both of the circlips 15 from the grooves in the internal wall of the sleeve member, whereafter one or both pipes can be removed, carrying the washers, the sealing rings and the grab rings associated therewith.

The coupling according to the invention has a number of advantageous features. Thus for example the sleeve member can be moulded in one piece, without requiring the provision of end caps for moulding or screwing or welding thereto, because of the use of an internal securing arrangement for the coupling components. Because there are no end caps extending radially outwardly of the sleeve member, the coupling has small external dimensions, which is practically desirable in pipework systems. Again, the unitary one piece sleeve member provides improved integrity in that no weaknesses arise from welds, joins, screw threads, etc. Yet again the use of the retaining ring enables a very simple assembly and dismantling operation, and also enables the utilisation of common elements for a range of couplings of similar size.

Claims

1. A pipe coupling including a unitary annular sleeve member formed from plastics material having at least one open end; an internal annular shoulder formed integrally within the sleeve having teeth which, in an unstressed condition, extend and project radially inwardly of the internal wall of the sleeve member and are inclined axially inwardly of the sleeve member, the grip member abutting within the sleeve member against the internal shoulder; 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; and a locating member engaging in at least one slot in the sleeve member opening at least partially within the sleeve member adjacent the open end thereof so that the locating member locates the sealing ring within the sleeve member.

2. A pipe coupling as claimed in claim 1 wherein the sleeve member is double ended and is provided with an annular shoulder, a grip member, a sealing ring and a locating member associated with each end thereof.

3. A pipe coupling as claimed in claim 2 wherein the integral internal shoulder is comprised by a central portion of the sleeve member of lesser internal diameter.

4. A pipe coupling as claimed in claim 2 or 3 including a centrally located internally protruding rib around the sleeve member.

5. A pipe coupling as claimed in claim 2, 3 or 4 wherein the or each locating member comprises a spring member engaging in at least one slot in the outer wall of the sleeve member, the slot or slots having a plurality of openings into the inside of the sleeve member through which the locating member extends to locate the associated sealing ring within the sleeve member.

6. A pipe coupling as claimed in claim 1, 2, 3 or 4 wherein the or each locating member comprises a generally annular member disposed in an annular groove extending around the inner wall of the sleeve member adjacent the or each open end thereof and locating the associated sealing ring within the sleeve member.

7. A pipe coupling as claimed in claim 6 including an annular disc provided within the sleeve on the axially inner side of the or each locating member against which the or each sealing ring abuts.

8. A pipe coupling as claimed in any one of the preceding claims wherein the sealing ring is in the form of an "0" ring.

9. A pipe coupling substantially as shown in and as hereinbefore described with reference to the accompanying drawing.

10. A pipe joint incorporating a pipe coupling as claimed in any one of the preceding claims.