GB2231931A - Pipe couplings - Google Patents

Abstract

Pipe couplings have a sleeve for fitting around the ends of pipes to be connected, annular thrust members adapted for insertion within each end of the sleeve about the pipes and a compression assembly for securing about a pipe of smaller diameter than that of the thrust member and adapted to be disposed within one end of the sleeve axially inwardly of the thrust member, said compression assembly comprising an inner member locatable axially inmost in the sleeve, an outer member locatable axially outmost in the sleeve and a compression member located between and adapted to be engaged by them whereby upon axial compressive force being applied to the assembly by the thrust member, the compression member is forced radially inwards to grip the pipe, the inner member, compression ring and outer member being provided with axially extending interlocking portions whereby upon axial compression they are axially linked together. <IMAGE>

Description

Pipe Couplings This invention relates to pipe couplings, and more particularly to pipe couplings incorporating a sleeve-like member adapted to encircle the juxtaposed butting ends of the pipes to be connected.

It is to be understood that the expression "pipe" as used herein means pipes and tubes as such and also pipe like members and fittings for use in pipework such as bends, elbows, "T" connectors, and parts and devices adapted to be fitted into pipework, such as valves and pumps.

Compression couplings for connecting pipes of polyethelene, lead and/or copper for domestic use of small diameter are known in which a sleeve is arranged to encircle the two juxtaposed ends of the pipes to be connected, the sleeve being provided at each end with internal threading, and an axially inward tapering surface leading in from each end, externally threaded thrust nuts being provided for screwing into the ends of the sleeve, such that when the inner edges of the thrust nuts engage the tapering portions of the sleeve, those edges are compressed inwardly so as, in use, to engage upon and grip adjacent the ends of juxtaposed pipes located within the sleeve.

Such couplings are known and used on pipes of polyethelene, lead and copper, and even steel and pvc pipes amongst others, where the coupling itself and its component thrust nuts are made from metal such as copper, bronze or brass or thermo-plastic materials.

There is, however, a problem in that within the context of domestic piping such as central heating piping or domestic water supply piping, pipes of different diametrical dimensions and different materials cannot readily be accommodated within such fittings which are essentially concerned with the connection of pipes of similar diameters.

It has been proposed to overcome this problem by using a grouping of small diameter inclined compression members or olives within one or other end of the sleeve, the olives being arranged, upon axial compression between the thrust ring and the internal inclined portion of the sleeve to be pressed upon a smaller diameter metallic pipe adjacent the end thereof to grip and seal the pipe within the coupling. However, such arrangements suffer from the disadvantage that the olive components can, upon disassembly of the pipe from the coupling, readily move within the coupling leading to misalignment and difficulty in remaking the coupling, or be accidently reassembled incorrectly should the coupling become dismantled, or even some of the components be lost. All of these problems can lead to a failure to make a satisfactory assembly on a pipe.

It is an object of the present invention to overcome or at least substantially reduce this problem.

In accordance with one aspect of the present invention there is provided a pipe coupling having a sleeve for fitting around the juxtaposed ends of two pipes to be connected, annular thrust members adapted for insertion within each end of the sleeve about pipes to be secured therewithin; and a compression assembly for securing about a pipe of significantly smaller diameter than the internal diameter of the thrust member and adapted to be disposed within one end of the sleeve axially inwardly of the thrust member at that end, said compression assembly comprising an inner member adapted in use to be located axially inmost in the sleeve, an outer member adapted to be located axially outmost in the sleeve and a compression member located between the inner and outer members adapted to be engaged by the inner and outer members whereby upon axial compressive force being applied to the assembly by the associated thrust member, the compression member is forced radially inwards to grip a pipe located therewithin, the inner member, the compression ring and the outer member being provided with axially extending interlocking portions whereby upon application of axial compressive force therebetween, they are axially linked together.

In accordance with another aspect of the present invention there is provided a pipe coupling having a sleeve for fitting around the juxtaposed ends of two pipes to be connected, the sleeve being threaded internally at each end, and having a surface axially inwardly of the threading at each end inclined inwards towards the central portion of the sleeve; externally threaded thrust nuts adapted for insertion within each end of the sleeve and screwing engagement therewithin, the thrust nuts each having internal edges adapted to be forced radially inwardly by the inclined surfaces of the sleeve; and a compression assembly for securing about a pipe of significantly smaller diameter than the internal diameter of the thrust nuts and adapted to be disposed within one end of the sleeve axially inwardly of the thrust nut at that end, and held therewithin between the inclined surface of that end of the sleeve, and the inward edge of the thrust nut when engaged in that end of the sleeve; said compression assembly comprising an inner cone member having a radially outer inclined surface adapted in use to engage the internal inclined surface of that end of the sleeve and a radially inner inclined surface, an outer cone member having a radially outwardly extending flange adapted to be engaged by the axially inner edge of the thrust nut and a radially inner inclined surface, and a compression member located between the inner and outer cone members having radially outer inclined surfaces adapted to be engaged by the radially inner inclined surfaces of the inner and outer cone members whereby upon axial pressure being applied upon the assembly the compression member is forced radially inwards to grip a pipe located therewithin, the inner cone member, the compression ring and the outer cone member being provided with axially extending interlocking portions whereby upon application of axial compressive force therebetween, they are axially linked together.

In a preferred embodiment, the compression assembly when interlinked will not become disengaged in normal usage, but can be disassembled if sufficient disengaging force is applied. The pipe of significantly smaller diameter is preferably formed of metal such as copper or steel.

By means of the invention it will be seen that a compression assembly is provided for accommodating within the compression coupling a pipe of considerably smaller diameter than the internal diameter of the thrust nuts of the coupling, such assembly being linked together when disposed within the coupling such that no part thereof can become separated, dislodged or misplaced on disassembly so that incorrect reassembly is avoided.

In addition it is to be noted that by means of the invention there is provided a strong positive connection of a smaller diameter pipe located within one or both ends of the compression coupling in which firm compression location and securement of that smaller diameter pipe is satisfactorily acomplished.

Internal liners may be provided with the coupling for use with one or other of the pipes, depending upon their material, located within the two ends of the sleeve.

The cone members have an innner diameter just larger than the maximum tolerance diameter of the pipe to be accommodated thereby, and the inner cone member may include, at its axially inmost end, a shoulder extending inwardly so as to locate the end of the pipe disposed therewithin adjacent the centre portion of the sleeve member, and a radially outwardly extending shoulder adapted to assist location of the compression assembly radially within the sleeve member.

The outer cone member may be provided at its axially outer end with a radially outwardly extending shoulder adapted to extend across at least the majority of the annular space between the outside wall of the pipe to be located therewithin, and the inside wall of the sleeve member.

Positive location between the elements of the compression assembly may be by means of axially extending arc like digits of the compression member having, at their outer ends, radially extending shoulders, the digits of the compression ring locating within appropriate apertures in the inner cone and the outer cone members, with the shoulders thereof clipping over appropriate abuttment surfaces of the inner cone and outer cone members for positive axial location therewith.

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 drawings in which: Figure 1 is a sectional elevation of one embodiment of a pipe coupling in accordance with the invention; and Figure 2 is an exploded isommetric view of part of the coupling of Figure 1; Referring now to the drawings it is to be seen that the coupling comprises a sleeve member having internally threaded ends within which are disposed inner inclined compression surfaces.

As can best be seen from Figure 1 a polyethelene or lead pipe 1 is inserted for coupling within one end of a sleeve 2 of the pipe coupling 3. A thrust nut 4 having external threads 5 is screwed into internal threads 6 at said one end of the sleeve 2 such that the innermost edge 7 of the thrust nut 4 is compressed radially inwardly by an inclined compression surface 8 of the sleeve 2 to engage, grip and seal upon the external surface of the polyethelene or lead pipe 1. The integrity of the diameter of the pipe is ensured by means of a liner 9 disposed within the pipe end. The diameter of the polyethelene or lead pipe is typically of the order of 25mm.

Within the other end of the sleeve 2 is located a compression assembly 10 for a smaller diameter copper pipe 11, typically of 15mm outside diameter. The compression assembly comprises an inner cone member 12 having at its axially inmost end a radially outwardly extending shoulder 13 adapted to locate radially the assembly 10 within the sleeve 2, and a radially inwardly extending shoulder 14 adapted to locate the axial end of the pipe disposed therewithin. At its axially outer end, the inner cone member is provided with a radially outer inclined surface 15, and a radially inner inclined surface 16.The compression assembly 10 also includes an outer cone member 17 having an internal diameter corresponding generally to the outer diameter of the copper pipe 11, and having, at its outer axial end an outwardly radially extending flange 18 adapted to fit within the annular space between the inner wall of the thrust nut 20 at that end and the outer wall of the copper pipe 11. At its axially inner end the outer cone member 17 is provided with an axially facing surface 19, adapted to be engaged by the innermost end 21 of the thrust nut 20, and a radially inner inclined surface 22.

Disposed between the inner cone member and the outer cone member of the compression assembly is a compression ring 23 having on its radially outer wall opposed inclined surfaces 24, 25 adapted to be engaged by the respective radially inclined surfaces 16, 22 of the inner cone member 12 and the outer cone member 17 respectively.

As can be appreciated from Figure 1 axially inward movement of the thrust nut 20 by appropriate movement between the screw threads of the sleeve 2 and the thrust ring will cause the axially inner edge 21 of the thrust ring 20 to bear upon the opposed shoulder 19 of the outer cone member 17 whereby the compression ring 23 is compressed both axially and radially between the inner cone member 12 and the outer cone member 17 via the respective inclined surfaces 16, 24 and 22, 25 so as to be forced radially inwardly to seal and grip upon the outer surface of the copper pipe located therewithin.

As can be seen in Figure 2 the compression ring is provided with axially extending digits 26, 27 adapted to fit within apertures 28, 29 in the inner cone member 12 and the outer cone member 17, the digits being provided at their outmost ends with shoulders 30, 31 such that upon insertion of the digits into the apertures the shoulders snap over the opposed surfaces 32, 33 of the'inner cone member 12 and the outer cone member 17 to hold the three elements of the compression assembly positively linked together.

It is to be observed that by means of the radially inward extending shoulder 14 of the inner cone member 12, the compression assembly cannot be fitted within the sleeve the wrong way round since in such incorrect disposition the pipe 11 could not be inserted. Hence, correct functioning of the compression assembly upon a copper pipe is always assured when the assembly is fitted within the sleeve and the thrust ring 20 screwed into the end thereof.

Again it is to be seen that by means of the positive linking together of the three elements of the compression assembly there is no possibility, upon dismantling of the coupling, of the component parts becoming dislodged, misplaced and otherwise giving rise to incorrect reassembly and ineffective jointing between two pipes.

The separate elements may be factory interconected together.

The coupling and its component parts may be formed from appropriate thermo-plastic materials such as polyamide and/or acetal plastics.

It is to be understood that the foregoing is merely exemplary of pipe couplings in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention.

Claims (11)

CLAIMS:

1. A pipe coupling having a sleeve for fitting around the juxtaposed ends of two pipes to be connected, annular thrust members adapted for insertion within each end of the sleeve about pipes to be secured therewithin; and a compression assembly for securing about a pipe of significantly smaller diameter than the internal diameter of the thrust member and adapted to be disposed within one end of the sleeve axially inwardly of the thrust member at that end, said compression assembly comprising an inner member adapted in use to be located axially inmost in the sleeve, an outer member adapted to be located axially outmost in the sleeve and a compression member located between the inner and outer members adapted to be engaged by the inner and outer members whereby upon axial compressive force being applied to the assembly by the associated thrust member, the compression member is forced radially inwards to grip a pipe located therewithin, the inner member, the compression ring and the outer member being provided with axially extending interlocking portions whereby upon application of axial compressive force therebetween, they are axially linked together.

2. A pipe coupling as claimed in Claim 1 wherein the sleeve is threaded internally at each end, and the annular thrust members comprise externally threaded thrust nuts adapted for screwing engagement within each end of the sleeve.

3. A pipe coupling as claimed in Claim 1 or 2 wherein the sleeve has an internal surface axially inwardly of each end thereof inclined inwards to the central portion of the sleeve, the annular thrust members having axially inner edges adapted to be forced radially inwardly by the inclined surfaces of the sleeve.

4. A pipe coupling as claimed in Claim 3 wherein the compression assembly is adapted to be disposed in one end of the sleeve between the inclined internal surface at that end of the sleeve, and the axially inner edge of an annular thrust member when located in that end of the sleeve.

5. A pipe coupling as claimed in Claim 4 wherein the inner member of the compression assembly is in the form of a cone having a radially outer inclined surface adapted in use to engage the internal inclined surface of the appropriate end of the sleeve, and a radially inner inclined surface; the outer member of the compression assembly is in the form of a cone having a radially outwardly extending flange adapted to be engaged by the axially inner edge of the appropriate annular thrust member, and a radially inner inclined surface; and the compression member of the compression assembly has radially outer inclined surfaces adapted to be engaged by the radially inner inclined surfaces of the inner and outer members whereby upon axial pressure being applied upon the assembly the compression member is forced radially inwards to grip a pipe located therewithin.

6. A pipe coupling as claimed in any one of the preceding claims wherein internal liners are provided with the coupling for use with one or both of the pipes to be coupled therewith, located within the two ends of the sleeve.

7. A pipe coupling as claimed in any one of the preceding claims wherein the inner member includes, at its axially inmost end, a shoulder extending inwardly so as to locate in use the end of the pipe disposed therewithin adjacent the centre portion of the sleeve member and a radially outwardly extending shoulder adapted to assist location of the compression assembly radially within the sleeve.

8. A pipe coupling as claimed in any one of the preceding claims wherein the outer member is provided at its axially outer end with a radially outwardly extending shoulder adapted to extend across at least the majority of the annular space between the outside wall of the pipe to be located therewithin, and the inside wall of the sleeve.

9. A pipe coupling as claimed in any one of the preceding claims wherein positive location between the elements of the compression assembly is by means of axially extending arc like digits of the compression member having, at their outer ends, radially extending shoulders, the digits of the compression member locating within appropriate apertures in the inner and the outer members, with the shoulder thereof clipping over appropriate abutment surfaces of the inner and outer members for positive axial location therewith.

10. A pipe coupling as claimed in any one of the preceding claims wherein the compression assembly is arranged for axial linking with sufficient firmness to remain inter-engaged in normal usage.

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