GB2280006A

GB2280006A - Push-fit pipe coupling

Info

Publication number: GB2280006A
Application number: GB9314222A
Authority: GB
Inventors: John Thurston Taylor
Original assignee: T H D MANUFACTURING Ltd
Current assignee: T H D MANUFACTURING Ltd
Priority date: 1993-07-09
Filing date: 1993-07-09
Publication date: 1995-01-18
Also published as: GB9314222D0

Abstract

A push-in type pipe coupling (1) comprises a housing (2) having a first bore (4) into which the end of a pipe is receivable, a gripping ring (11) having a plurality of radially inwardly extending gripping fingers (12) arranged in a substantially conical array converging towards the first bore (4), a first conical abutment (9) situated between the gripping ring (11) and the first bore (4) and a release sleeve (13) mounted in the housing (2) for axial reciprocal movement, the release sleeve (13) being coaxial with the first bore (4) and having an internal diameter substantially equal to that of the first bore (4) and having at its end adjacent the first bore (4) a second conical abutment (16) adapted to engage the gripping fingers (12) adjacent their free ends when the sleeve (13) is moved towards the first bore (4) to urge the free ends radially outwards. <IMAGE>

Description

PIPE COUPLING The present invention relates to pipe couplings, and is particularly concerned with releasable pipe couplings which enable pipes, particularly domestic water pipes, to be releaseably connected without the use of tools.

According to the present invention a pipe coupling comprises a housing having a first bore into which the end of a pipe is receivable, a gripping ring having a plurality of radially inwardly extending griping fingers arranged in a substantially conical array coaxial with, and converging towards, the first bore, a first conical abutment situated between the gripping ring and the first bore and a release sleeve mounted in the housing for axial reciprocal movement, the release sleeve being coaxial with the first bore and having an internal diameter substantially equal to that of the first bore and having at its end adjacent the first bore a second conical abutment adapted to engage the gripping fingers adjacent their free ends when the sleeve is moved towards the first bore to urge the free ends radially outwards.

An embodiment of the present invention will now be described in detail, with reference to the accompanying drawings, in which: Figure 1 shows a longitudinal section of a pipe fitting.

Referring now to Figure 1, there is shown a pipe fitting 1 for connecting a rigid plastics or metal pipe of diameter D to a flexible hose (not shown).

The pipe fitting 1 comprises a hose spigot end 2 and a pipe coupler end 3. It will be readily appreciated that the pipe coupler end 3 may be formed as part of a plastics plumbing fitting such as a 'T', 'Y', 'L' or a straight connector usable with tubes of any nominal diameter D.

The pipe coupling end 3 comprises a locating bore 4 of nominal diameter D, into which the end portion of the pipe is received to locate the pipe coupling end 3 in relation to the pipe.

Adjacent the locating bore 4 is an enlarged bore 5, which accommodates a sealing ring 6. The sealing ring 6 is shown as an '0' ring, but may have any suitable configuration to form a fluid-tight seal between the outside surface of the pipe and the surface of the enlarged bore 5.

The locating bore 4 and enlarged bore 5 are formed in a body which is integral with the hose connector spigot 2, preferably formed from plastics material.

Extending from the body beyond the enlarged bore 5 is a retaining sleeve 7. The retaining sleeve 7 is permanently fixed to the body by a welded or screw-threaded connection, or by any other suitable means such as by adhesive bonding. The retaining sleeve 7 has an internal step 8 facing towards the body, and retained between the step 8 and the end surface of the body is a substantially rigid ring 9 whose internal diameter is substantially equal to the nominal diameter D. The ring 9 includes a chamfered face 10 on its side remote from the enlarged bore and locating bore 4 and 5, for a purpose which will be described below.

A resilient collet 11, having a conical array of inwardly-extending teeth 12 is situated adjacent the ring 9, a planar outer part of the collet 11 bearing against the ring 9, and the teeth 12 of the collet extending in a conical array adjacent the chamfered face 10 of the ring 9. It will be readily appreciated that the cone angle of the chamfered face 10 is less than the cone angle of the collet teeth 12. The collet 11 and the ring 9 are retained between the step 8 of the retaining sleeve 7 and the end surface of the body, there being a clearance to allow free rotation of the collet 11 about the axis of the coupling.

A release plunger 13 is retained within the end portion of retaining sleeve 7, the release plunger 13 having an internal bore of nominal diameter D, and being axially movable in relation to the coupling 1. The release plunger 13 is preferably formed from plastics material, and is retained within the retaining sleeve 7 by means of a snap engagement between outwardly projecting barbs 14 of the release plunger 13 cooperating with internal grooves 15 in the retaining sleeve 7. It will be appreciated that the internal grooves 15 of the retaining sleeve 7 do not extend to the extreme end of the retaining sleeve, but provide an axially directed end surface against which the barbs 14 may abut to limit axial movement of the release plunger 13 relative to the retaining sleeve 7.

At the inner end of the release plunger 13, a conical surface 16 is formed. The cone angle of the conical surface 16 is less than the cone angle of the teeth 12 of the collet 11, and may be substantially equal to the cone angle of the chamfered face 10 of the ring 9.

In operation, the coupling is attached to a pipe of nominal diameter D, by introducing the pipe end through the bore of the release plunger, through the collet 11, through the ring 9 and enlarged bore 5, and into the locating bore 4. The inner end of the locating bore 4 has an axially directed surface S which acts as an end stop.

The teeth 12 of the collet 11, as is clear from the illustration, extends radially inwardly so that the clearance between radially opposed tips of the teeth 12 is slightly less than the nominal diameter D of the pipe. As the pipe enters the coupling, the teeth 12 of the collet 11 are resiliently deflected, so as to increase the clearance between their tips and allow the pipe to enter the coupling. Due to the conical arrangement of the teeth 12, however, any tensile force applied to the pipe will simply cause the ends of the teeth 12 to 'dig in' into the pipe's surface and thus resist withdrawal of the pipe from the coupling.

In order to ensure a fluid-tight coupling, the sealing ring 6 is provided with an internal dimension slightly less than the nominal diameter D of the pipe, so that as the pipe is introduced through the enlarged bore 5 into the locating bore, the sealing ring 6 is compressed between the outer surface of the pipe and the surface of the enlarged bore 5 to create a fluid-tight seal.

In order to release the coupling, the release plunger 13 is urged axially of the pipe so that the conical surface 16 of the release plunger 13 engages the teeth 12 of the collet 11, and presses them into close engagement with the chamfered surface 10 of the ring 9. This deflection of the teeth 12 causes the distance between opposing tips to be increased, thus releasing the pipe from the grip of the collet. By holding the release plunger 13 in this position, the pipe D may be easily withdrawn from the coupling.

Having described the coupling according to the invention, it will be clear that two coupling constructions such as have been described may be joined end to end to produce a coupling element suitable for joining two lengths of rigid pipe. Likewise, two or more of the coupling elements may be used to form 'L', 'T' or 'Y' junctions, so that easily releasable plumbing installations may be made.

In the embodiment described, the release plunger 13 is held captive in the retaining sleeve 7 by means of radially outwardly extending barbs 14 engaging into internal grooves 15 in the retaining sleeve. It will be readily appreciated that the retaining sleeve 7 may be formed with an external protrusion or recess which can cooperate with a corresponding formation on the release plunger 13 to hold the release plunger 13 captive to the retaining sleeve 7.

The collet 11 is preferably formed from stainless steel, but other suitable materials are beryllium copper alloys and spring steel. In the preferred embodiment, the cone angle of the chamfered surface 10 is 900, i.e. the angle between the chamfered surface 10 and the axis of the coupling is 450. The cone angle of the conical surface 16 of the release plunger must be equal to or less than the cone angle of the chamfered face 10 of the ring 9. The cone angle of the teeth 12 of the collet 11 in the unstressed condition is preferably approximately 30 , the only limitation on the cone angle of the collet teeth 12 is that the cone angle must be greater than the cone angle of the chamfered surface 10, and greater than the cone angle of the conical surface 16 of the release plunger 13.

The preferred materials for the body, retaining sleeve 7, ring 9 and release plunger 13 are substantially rigid plastics materials, polyphenylene ether (PPE) being a preferred material. It will be appreciated, however, that the component parts may be machined from metal, and a threaded connection may be formed between the retaining sleeve 7 and the body of the coupling. Where plastics materials are used for the components, the components may be assembled by heat, ultrasonic or solvent welding, or by adhesive bonding to join the retaining sleeve 7 to the body. The remaining components are retained by virtue of their interlocking shapes.

The connections of the present invention will find utility in any plumbing fitting where releasability is required, and are particularly suitable for the connection of washing machines, shower pumps, etc.

Claims

1. A push-in type pipe coupling comprising a housing having a first bore into which the end of a pipe is receivable, a gripping ring having a plurality of radially inwardly extending griping fingers arranged in a substantially conical array coaxial with, and converging towards, the first bore, a first conical abutment situated between the gripping ring and the first bore and a release sleeve mounted in the housing for axial reciprocal movement, the release sleeve being coaxial with the first bore and having an internal diameter substantially equal to that of the first bore and having at its end adjacent the first bore a second conical abutment adapted to engage the gripping fingers adjacent their free ends when the sleeve is moved towards the first bore to urge the free ends radially outwards.

2. A pipe coupling according to Claim 1, wherein the housing, first abutment, and release sleeve are plastics components.

3. A pipe coupling according to Claim 1 or Claim 2, wherein a sealing ring is interposed between the first bore and the first abutment.

4. A pipe coupling according to any preceding Claim, wherein the axial reciprocal movement of the sleeve is limited, in the direction away from the first bore, by cooperating abutment surfaces on the sleeve and the housing.

5. A pipe coupling according to Claim 4, wherein the abutment surface of the sleeve extends radially outwardly from the sleeve surface.

6. A pipe coupling substantially as described herein with reference to the accompanying drawing.