GB2566665A

GB2566665A - Push fit pipe coupling comprising a demount collar

Info

Publication number: GB2566665A
Application number: GB1706107.8A
Authority: GB
Inventors: Nicholas Whiteley Paul
Original assignee: Pegler Yorkshire Group Ltd
Current assignee: Aalberts Integrated Piping Systems Ltd
Priority date: 2017-04-18
Filing date: 2017-04-18
Publication date: 2019-03-27
Anticipated expiration: 2037-04-18
Also published as: GB2566665B; GB201706107D0

Abstract

A push-fit pipe coupling comprises a tubular body 102 with a socket having an interior thread 104 and retaining internally a grab ring 112 and a demount collar 113. The demount collar has a contact surface 115 to press against the teeth of the grab ring to push them from a normal position to a demounting position. The demount collar is provided with an external thread 116 corresponding to the interior thread of the socket, such that screwing the demount collar inwards with respect to the tubular body presses the contact surface against the teeth of the grab ring to move them to the demounting position. Unscrewing the demount collar relieves pressure against the teeth and allows them to move into a normal, gripping, position. The demount collar is also provided with axially oriented connection features 117, such as recesses, notches or holes, for connection to corresponding axially oriented connection features (118, fig. 3a) of a tool (119, fig. 3a), such that rotation of the tool connected to the demount collar effects rotation of the demount collar. The tool is formed as a part ring.

Description

Push fit pipe coupling comprising a demount collar

Technical Field of the Invention

The present invention relates to push-fit pipe couplings and in particular for improvements in relation to demountable push-fit pipe slip couplings.

Background to the Invention

When connecting together pipes, one common form of coupling is a push-fit pipe coupling. Typically, such a coupling comprises a tubular body adapted to retain internally a sealing ring and a grab ring. The sealing ring typically comprises a resiliently deformable ring adapted to form a close seal with a pipe inserted into the 10 coupling and the grab ring comprises a plurality of teeth angled radially and axially inward so as to allow the insertion of a pipe but resist the removal of said pipe.

Such a coupling facilitates adjustment only in the direction of insertion, which is fine where the coupling is intended for the end of the pipe. In such cases, the coupling may include a pipe stop to limit insertion. In the case of slip couplings which omit a 15 pipe stop to facilitate more flexible use, this may not always be desirable. In particular, slip couplings are often used when installing 'pre-made' systems into buildings and in such circumstances the depth of insertion of the pipe into the coupling may need to be varied to cope with slight variations in the building or pipework dimensions, particularly if a pipe is inserted too far into the coupling on initial use.

Accordingly, some such fittings are provided with a demount collar having an engagement portion projecting outside the body of the coupling. A demount tool can be brought to bear on the engagement portion so as to force the demount collar axially into the coupling. When the demount tool forces the demount collar into the coupling an angled contact surface of the demount collar presses against the teeth of the grab ring, thereby pushing them away from the inserted pipe, allowing two-way adjustment. Whilst such demount collars do provide for some level of adjustment, they are not particularly convenient, since a user has to maintain pressure on the demount tool whilst manipulating the pipe. However, these are still the most popular type of arrangements, despite the availability of more user friendly, but complicated, arrangements.

GB2525879 discloses an improved push fit pipe coupling assembly comprising a push-fit pipe coupling and a demount tool, the push-fit pipe coupling comprising a tubular body provided with an exterior thread and adapted to retain internally: a sealing ring; a grab ring; and a demount collar having an engagement portion projecting outside the body of the coupling, the demount tool comprising a part ring provided with: a threaded portion adapted to engage with the exterior thread of the coupling body so as to enable the demount tool to move axially relative to the body of the coupling; and a pressing portion adapted to press on the engagement portion of the demount collar when the demount tool is moved axially to a demount position.

EPI020677, on the other hand, discloses another push-fit pipe coupling assembly, in which the tubular body is provided with an internal, or external thread, into/onto which a “disconnection means” can be threaded, so as to be screwed axially inward and thereby press against the teeth of the grab ring. This “disconnection means”, is effectively a demount collar and is provided with an outside surface portion of polygonal section designed to extend outside the coupling and cooperate with a driving tool. The assembly of EP1020677 also has a guide socket, which takes the place of the disconnection means in ordinary operation, being arranged for guiding a pipe end into the coupling assembly. The disconnection means has studs which co3 operate with holes in the guide socket, so that it can be used as a tool to remove the guide socket (which in normal use is flush with the end of the coupling), before replacing it as discussed above, to disconnect the pipe.

The present invention seeks to provide an improved push fit pipe coupling 5 assembly comprising a demount collar.

Summary of the Invention

According to a first aspect of the invention, there is provided a push-fit pipe coupling comprising: a tubular body provided with at least one socket having an interior thread and retaining internally a grab ring and a demount collar having a contact surface to press against the teeth of the grab ring to push them from a normal position to a demounting position; wherein the demount collar is provided with an external thread corresponding to the interior thread of the socket, such that screwing the demount collar inwards with respect to the tubular body presses the contact surface against the teeth of the grab ring to move them to the demounting position and unscrewing the demount collar outwards with respect to the tubular body relieves pressure against the teeth and allows them to move into a normal, gripping, position; characterised in that the demount collar is provided with one or more axially oriented connection features for connection to one or more corresponding axially oriented connection features of a tool, such that rotation of the tool connected to the demount collar effects rotation of the demount collar.

With such an arrangement, the demount collar can be operated, with a special tool even if it does not project beyond the axial end of the socket, and can even be held captive in the socket, such that it cannot be completely unscrewed from the fitting and potentially lost. This can have a number of advantages not seen in the prior art.

Notably, unlike the prior art of GB2525879 in which the collar extends from the socket once the tool is removed, and can be pushed inwards accidentally (or deliberately 5 but in error) and cause the grab ring to demount, pushing axially on the demount collar of the invention will have no effect, because of the screw threads. If captive, or not projecting beyond the axial end of the socket, even with ordinary tools (e.g. spanners) it cannot be adjusted. The demount collar could even extend outside the axial end of the socket and provided its outer circumferential surface is not provided with connection features, for example if it is a smooth cylindrical surface, accidental adjustment, or adjustment by an unauthorised person, without the correct tool, would not be possible.

Effectively, this means that the invention can achieve an advantage obtained by EPI020677 that when the demount collar is not in use, it is not able to be accidentally adjusted, however, this is done without the rigmarole of removing the demount collar entirely and replacing it with a separate device (the guide socket) and without the risk of losing the demount collar once removed. The demount collar of the invention, of course, operates as a guide socket as well as a demount collar.

The demount collar may have no connection features accessible on its outer circumferential surface. For example, the outer circumferential surface may be a smooth cylindrical surface. It could even be a conical surface, reducing in diameter in the axially external direction.

The one or more connection features of the demount collar may be recesses, notches or holes in its axially outer face. Recesses, notches or holes are less likely to be accidentally interacted with and more difficult even for a determined, but unauthorised, person to engage with than features projecting axially from the end of the demount collar.

The demount collar may be provided with at least two, or at least three connection features spaced (optionally evenly spaced) around the circumference of its axial end.

The connection features may be notches extending (inward) from the outer 10 circumferential surface of the demount collar. This is straightforward to produce, and most preferable when no part (i.e. substantially no part) of the demount collar extends axially beyond the end of the socket (since notches from the external surface, could otherwise potentially make gripping the external surface easier).

As set out above, the invention can be particularly effective when the demount 15 collar does not project (axially) beyond the end of the socket (when the grab ring is in its normal position). Accordingly, it is preferably flush with the end of the socket, or arranged entirely internally of the end of the socket in that state. However, a small amount of projection (such that the outer surface cannot be easily grabbed and twisted, even with a pipe wrench or the like) is acceptable.

Consequently, the push fit pipe coupling may be comprise a demount collar configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 10mm, 5mm, 3mm or 1mm.

The push-fit pipe coupling may further comprise a sealing ring.

The push fit pipe coupling may further comprise a protection ring separating the sealing ring and the grab ring.

The tubular body may comprise a separate socket portion and body portion. The socket portion may snap-fit to the body portion.

The protection ring may snap fit to the socket portion (or the body portion).

The coupling may comprise a support ring and the grab ring may be sandwiched between the protection ring and the support ring.

The tubular body may comprise a threaded insert to provide the internal thread. The threaded insert may be configured to co-operate with the protection ring to provide a support for the grab ring and to retain the sealing ring.

A second aspect of the invention extends to a tool for use with a demount collar of a pipe fitting according to the first aspect of the invention, the tool comprising a partring (i.e. not a complete ring) provided with one or more axially oriented connection features for connection to one or more corresponding axially oriented connection features of the demount collar.

The one or more connection features of the demount tool are preferably projections e.g. pins, which may be integral with, or attached to the body of the tool. The demount tool may be provided with two, or three connection features, which may be circumferentially spaced, optionally equally circumferentially spaced, around the part-ring.

The demount tool may be provided with radially extending arms such that it can be operated by hand, without any further tool (such as a spanner or the like).

Alternatively, it may be provided with connection features, such as flats, on its outer surface, for engagement with a tool, such as a spanner.

A third aspect of the invention provides a kit of parts comprising a push-fit pipe coupling according the first aspect of the invention (optionally including any optional features thereof) and a demount tool according to the second aspect of the invention (optionally including any optional features thereof).

A fourth aspect of the invention provides a method of demounting a grab ring from a pipe in a pipe coupling according to the first aspect of the invention (optionally including any optional features thereof) comprising introducing a demount tool according to the second aspect of the invention (optionally including any optional features thereof) over the pipe, engaging the connection features of the demount tool with the connection features of the demount collar and turning the demount tool so as to push the teeth of the grab ring into a demounting position.

Detailed Description of the Invention

In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows an exploded isometric view of a first push-fit pipe coupling;

Figure 2a shows a lateral part cross-sectional view through the push-fit pipe coupling of figure 1 co-operating with a demounting tool, in the normal position;

Figure 2b	shows a lateral part cross-sectional view through the push-fit pipe coupling of figure 1 co-operating with a demounting tool, in the demounting position;
Figures 3a-e	show isometric views of the stages of demounting of a pipe from the
5	push-fit pipe coupling of figures 1 to 2b;
Figure 4	shows an exploded isometric view of a second push-fit pipe coupling prior to assembly;
Figure 5a	shows a lateral part cross-sectional view through the push-fit pipe coupling of figure 4 co-operating with a demounting tool, in the normal
10	position;
Figure 5b	shows a lateral part cross-sectional view through the push-fit pipe coupling of figure 4 co-operating with a demounting tool, in the demounting position; and
Figures 6a-e	show isometric views of the stages of demounting of a pipe from the
15	push-fit pipe coupling of figures 4 to 5b.

Referring to the figures, two embodiments of push fit pipe couplings 100, 200 are shown, that of figures 1 to 3e being plastic bodied and that of figures 4 to 6e being metal bodied. Those skilled in the art will readily choose suitable materials.

Turning to the first embodiment of figures l-3e and with particular reference to 20 figures 1, 2a and 2b, a push-fit pipe coupling 100 is provided. In this embodiment, the push-fit pipe coupling is straight and comprises a straight tubular body 101 provided with a socket 102 at each end.

The sockets 102 of this embodiment are snap-fit onto the tubular body 102 via snap-fit arrangements 103 to fix each socket (irrotatably) on the tubular body. Each socket 102 has an interior thread 104 inward of its mouth.

The tubular body 101 is formed (e.g. by injection moulding) so as to have an 5 internally extending circumferential rib 105 at its longitudinal centre, which serves as a stop, having two opposing stop faces to prevent a pipe 106 being inserted too far into the pipe coupling 100 from one end or the other.

On each side, axially outwardly of the rib 105, and beyond the region where the snap fit arrangements 103 are provided, a section having a larger bore is provided, thus forming a shoulder 107.

An o-ring seal 108 is fitted in this larger bore section held against the shoulder 107 to prevent inward movement. To prevent the seal from coming outward, and to guide the pipe 106, a protection ring 109 is provided. The protection ring 109 is arranged to snap fit into the socket 102 and is shaped to sit internally around the axial end of the tubul ar b ody 101.

The sockets 102 are formed with axially inwardly facing shoulders 110, inward of their threaded portion 104, and a support ring 111 is sandwiched between the axially outermost face of the protection ring and the shoulder 110 of the socket 102.

The protection ring is further provided with a circumferential recess at its axially 20 outer end, so as to provide a radially internal gap/slot, in which a grab ring 112 is arranged, with its teeth facing axially and radially inwardly.

The coupling 100 further comprises a demount collar 113. The demount collar has an engagement surface 114 at its axially outer end, and an angled contact surface

115 arranged to press against the teeth of the grab ring 112 in use to push them from a normal position to a demounting position.

Between the contact surface 115 and the engagement surface 114, the demount collar 113 is provided with an external thread 116 corresponding to the interior thread

104 of the socket 102.

Screwing the demount collar 113 inwards with respect to the tubular body 101 presses the contact surface 115 against the teeth of the grab ring 113 to move them to the demounting position shown in figure 2b, and unscrewing the demount collar 113 outwards with respect to the tubular body 101 relieves pressure against the teeth and allows them to move into a normal, gripping, position shown in figure 2a.

The demount collar 113 is sized and shaped such that when unscrewed to the extent that the contact surface 115 is not pressing against the teeth of the grab ring 112, it is flush with, and does not project beyond, the axial end of the socket 102.

Thus, in order to allow the demount collar 113 to be operated (by twisting it so 15 that it screws into and out of the socket 102), it is provided with a plurality of axially oriented connection features 117 for connection to corresponding axially oriented connection features 118 of a tool 119 shown in figures 3a-3e, such that rotation of the tool 119 connected to the demount collar 113 effects rotation of the demount collar 113.

In this embodiment, the connection features 117 are three notches equally 20 spaced around the axial contact surface 115 and formed as cut-outs from the circumferential surface of the collar 113, so as to provide three axially inwardly extending cavities, with which three corresponding axially extending projections on the tool 119 can engage to operate the demount collar 113 even though it does not project beyond the axial end of the socket 102.

Turning to the tool 119 it has a plastic body comprising a part-ring, i.e. not a complete ring, but a ring-shape subtending less than 300 degrees, but more than 240 5 degrees, e.g. about 270 degrees and having a gap 121 between its ends. The tool 119is provided with three axially oriented pins as connection features 118 for connection to the corresponding axially oriented connection features 117 of the demount collar 113.

Since the three notches 117 are equally spaced around the collar, the three pins are correspondingly spaced 120 degrees apart from one another.

In line with each projecting pin 118, an arm 120 extends radially outwardly from the tool 119, allowing the tool to be turned by hand, without any further tool (such as a spanner or the like).

The plastic body of the tool 119 is resilient, so that it can be forced over a pipe, with the circumferential ends of the part-ring moving apart from one another to allow the pipe to fit through the gap 121 therebetween, then moving back together, such that the pins 118 are once again suitably arranged to engage the notches 117.

Referring to figures 3a-e, in use, the tool 119 is placed over a pipe 106 (normally as described above, pushing it over the pipe, through the gap 121), with the connection features 118 of the tool facing the connection features 117 of the demount collar. The 20 tool 119 is then moved along the pipe and the engagement features 117, 118 are brought into engagement with one another.

The tool is then turned, so as to screw the demount collar 113 axially inwards, into the socket 102, such that, the contact surface 115 of the demount collar 113 engages with the teeth of the grab ring 112, pushing them axially outwards from their normal position shown in figure 2a, and out of engagement with the external surface of the pipe 106, to a demount position shown in figure 2b.

Then, with reference to figure 3c, the pipe 106 can be moved axially outwardly, 5 for adjustment or complete decoupling.

Following complete decoupling, or adjustment, the tool 119 can be unscrewed as shown in figure 3d, bringing the demount collar 113 back flush with the axial outer end of the socket and releasing the force on the teeth of the grab ring from the contact surface of the demount collar, allowing them to return to the normal position and grip a pipe 106 inserted into the coupling, to restrict outward movement thereof. Features, not shown, can be provided to restrain the demount collar from moving beyond the axial end of the socket 102.

Once the demount collar 113 is back in its normal position, the tool 119 can be removed for safekeeping as shown in figure 3e.

Turning to the second embodiment of figures 4 to 6e and with particular reference to figures 4, 5a and 5b, a push-fit pipe coupling 200 is provided. In this embodiment, the push-fit pipe coupling is again straight and comprises a straight tubular body 201 provided with a socket 202 at each end.

The tubular body 201 of this embodiment is formed of metal, with the sockets

202 being integral with tubular body 202, each crimped at its axially outermost end to retain components within.

Contrarily to the first embodiment, in which each socket is formed with an interior thread, in this embodiment, a threaded insert 204, which has an internal thread, is irrotatably fastened to the internal surface of the socket 202 (e.g. by adhesive or snapfit features not shown).

The tubular body 201 is formed (e.g. by pressing) so as to have an internally extending circumferential rib 205 at its longitudinal centre, which serves as a stop, 5 having two opposing stop faces to prevent a pipe 206 being inserted too far into the pipe coupling 200 from one end or the other.

On each side of the pipe coupling, axially outwardly of the rib 105, a section having a larger bore is provided, thus forming a shoulder 207.

An o-ring seal 208 is fitted in this larger bore section held against the shoulder 10 207 to prevent inward movement. To prevent the seal 208 from coming outward, and to guide the pipe 206, a protection ring 209 is provided axially outward of the sealing ring 208. The protection ring 109 is provided with an externally extending flange arranged to abut a second shoulder 203 of larger dimension than the first shoulder 207 on one side, and to abut the end of the insert 204 on the other side, so as to be sandwiched therebetween.

The threaded insert is also provided with an axially inwardly facing shoulder 210 which faces the axially outer end of the protection ring, and thus provides a slot, in which the grab ring 212 is arranged, with its teeth facing axially and radially inwardly.

The coupling 200 further comprises a demount collar 213. The demount collar 20 213 again has an engagement surface 214 at its axially outer end, and an angled contact surface 215 arranged to press against the teeth of the grab ring 212 in use to push them from a normal position to a demounting position.

Between the contact surface 215 and the engagement surface 214, the demount collar 213 is provided with an external thread 216 corresponding to the interior thread of the threaded insert 204.

The ends 211 of the sockets 202 are crimped to hold all of the abovementioned 5 components in place, including keeping the demount collar 213 captive within the coupling 200.

Screwing the demount collar 213 inwards with respect to the tubular body 201 presses the contact surface 215 against the teeth of the grab ring 213, in just the same way as the first embodiment, so as to move them to the demounting position shown in figure 5b, and unscrewing the demount collar 213 outwards with respect to the tubular body 201 relieves pressure against the teeth and allows them to move into a normal, gripping, position shown in figure 5 a.

The demount collar 213 is sized and shaped such that when unscrewed to the extent that the contact surface 215 is not pressing against the teeth of the grab ring 212, it is flush with, and does not project beyond, the crimped axial end 211 of the socket 202. The external thread of the demount collar 213 have a larger diameter than the inner diameter of the mouth of the crimped end 211, to hold the collar captive in the coupling 200.

Again, in order to allow the demount collar 213 to be operated (by twisting it so that it screws into and out of the socket 202), it is provided with a plurality of axially oriented connection features 217 for connection to corresponding axially oriented connection features 218 of a tool 219 shown in figures 6a-6e, such that rotation of the tool 219 connected to the demount collar 213 effects rotation of the demount collar 213.

In this embodiment, the connection features 217 are two notches equally spaced, opposite each other on the axial contact surface 215 and formed as cut-outs from the axial contact surface of the collar 213, so as to provide two axially inwardly extending cavities, with which two corresponding axially extending projections on the tool 219 can engage to operate the demount collar 213 even though it does not project beyond the axial end of the socket 202.

Turning to the tool 219, as in the first embodiment, it has a plastic body comprising a part-ring, i.e. not a complete ring, but a ring-shape subtending less than 300 degrees, but in this case more than 180 degrees. The part ring in this case is formed as a circular section with a u-shape cut-out, so as to have a part-cylindrical internal surface 222 extending around 180 degrees with legs extending away therefrom, allowing a gap 221 therebetween. The tool 219 is provided with two axially oriented pins as connection features 218 for connection to the corresponding axially oriented connection features 217 of the demount collar 213. Since the two notches 217 are equally spaced around the collar 213, the two pins are correspondingly spaced 180 degrees apart from one another.

The external circumferential surface of the tool 219 is provided with longitudinally extending ridges, allowing the tool to be gripped and turned by hand, without any further tool (such as a spanner or the like).

The plastic body of the tool 219 need not be resilient, since the gap 221 is sufficiently large to fit round a pipe 206, as the pins 218 are 180 degrees apart.

Referring to figures 6a-e, use of the coupling 200 and tool 219 of the second embodiment is very similar to that of the first embodiment: in use, the tool 219 is placed over a pipe 206, pushing it over the pipe 206, through the gap 221, so that the inner cylindrical surface 222 abuts the external cylindrical surface of the pipe 206 and the connection features 218 of the tool 219 face the connection features 217 of the demount collar 213. The tool 219 is then moved along the pipe 206 and the engagement features 5 217, 218 are brought into engagement with one another as shown in figure 6b.

The tool 219 is then turned, so as to screw the demount collar 213 axially inwards, into the socket 202, such that, the contact surface 215 of the demount collar

213 engages with the teeth of the grab ring 212, pushing them axially outwards from their normal position shown in figure 5a, and out of engagement with the external surface of the pipe 206, to a demount position shown in figure 5b.

Then, with reference to figure 6c, the pipe 206 can be moved axially outwardly, for adjustment or complete decoupling.

Following complete decoupling, or adjustment, the tool 219 can be unscrewed as shown in figure 6d, bringing the demount collar 213 back flush with the axial outer end of the socket and releasing the force on the teeth of the grab ring 212 from the contact surface 215 of the demount collar 213, allowing them to return to the normal position and grip a pipe 206 inserted into the coupling, to restrict outward movement thereof.

As set out above, the crimped end 211 of the socket 202 prevents the demount collar 213 from being unscrewed right out of the coupling 200. Once the demount collar 213 is back in its normal position, the tool 219 can be removed for safekeeping as shown in figure 6e.

Whilst the invention has been described in relation to straight double ended couplings, it is equally possible to couplings with bends in, to provide single ended couplings, or indeed couplings in tee or cross form.

The above embodiments are described by way of example only. Many 5 variations are possible without departing from the scope of the invention as defined in the appended claims.

1. A push-fit pipe coupling comprising: a tubular body provided with at least one socket having an interior thread and retaining internally a grab ring and a demount collar having a contact surface to press against the teeth of the grab 5 ring to push them from a normal position to a demounting position; wherein the demount collar is provided with an external thread corresponding to the interior thread of the socket, such that screwing the demount collar inwards with respect to the tubular body presses the contact surface against the teeth of the grab ring to move them to the demounting position and unscrewing the demount collar outwards with respect to the tubular body relieves pressure against the teeth and allows them to move into a normal, gripping, position;

characterised in that the demount collar is provided with one or more axially oriented connection features for connection to one or more corresponding axially oriented connection features of a tool, such that rotation of the tool connected to the demount collar effects rotation of the demount collar.

2. A push-fit pipe coupling according to claim 1 wherein the demount collar has no connection features accessible on its outer circumferential surface.

3. A push-fit pipe coupling according to claim 1 or 2 wherein the one or more connection features of the demount collar are recesses, notches or holes in its axially outer face.

4. A push-fit pipe coupling according to any preceding claim wherein the demount collar is provided with at least two connection features spaced around the circumference of its axial end.

5. A push-fit pipe coupling according to any preceding claim wherein the connection features are notches extending from the outer circumferential surface of the demount collar.

6. A push-fit pipe coupling according to any preceding claim wherein the demount collar is flush with, or arranged entirely internally of the end of the socket when the grab ring is in its normal position.

7. A push-fit pipe coupling according to any preceding claim wherein the demount collar is configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 10mm.

8. A push-fit pipe coupling according to any preceding claim wherein the demount collar is configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 5mm

9. A push-fit pipe coupling according to any preceding claim wherein the demount collar is configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 3mm

10. A push-fit pipe coupling according to any preceding claim wherein the demount collar is configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 1mm.

11. A push-fit pipe coupling according to any preceding claim further comprising a sealing ring.

12. A push-fit pipe coupling according to claim 11 further comprising a protection ring separating the sealing ring and the grab ring.

13.	A push-fit pipe coupling according to any preceding claim wherein the tubular body comprises a separate socket portion and body portion.
14.	A push-fit pipe coupling according to claim 13 wherein the socket portion snap-fits to the body portion.
5 15.	A push-fit pipe coupling according to claim 13 or 14 wherein the protection ring snap fits to the socket portion or the body portion.
16.	A push-fit pipe coupling according to any of claims 12 to 15 wherein the coupling comprises a support ring and the grab ring is sandwiched between the protection ring and the support ring.
10 17.	A push-fit pipe coupling according to any preceding claim wherein the tubular body comprises a threaded insert to provide the internal thread.
18.	A push-fit pipe coupling according to claim 17 when dependent directly or indirectly on claim 14 wherein the threaded insert is configured to co-operate
15	with the protection ring to provide a support for the grab ring and to retain the sealing ring.
19.	A demount tool for use with a demount collar of a pipe fitting according to any preceding claim, the tool comprising a part-ring provided with one or more axially oriented connection features for connection to one or more corresponding axially oriented connection features of the demount collar.
20 20.	A demount tool according to claim 19 wherein the one or more connection features of the demount tool are projections.

21. A demount tool according to claim 19 or 20 provided with two, or three connection features.

22. A demount tool according to any of claims 19 to 21 wherein the connection features are circumferentially spaced around the part-ring.

23. A demount tool according to claim 22 wherein the connection features are equally circumferentially spaced around the part-ring.

24. A demount tool according to any of claims 19 to 23 comprising radially extending arms.

25. A kit of parts comprising a push-fit pipe coupling according to any of claims 1 to 18 and a demount tool according to any of claims 19 to 24.

26. A method of demounting a grab ring from a pipe in a pipe coupling according to any of claims 1 to 18 comprising introducing a demount tool according to any of claims 19 to 24 over the pipe, engaging the connection features of the demount tool with the connection features of the demount collar and turning the demount tool so as to push the teeth of the grab ring into a demounting position.

Amendments to the claims have been filed as follows

Claims

1. A push-fit pipe coupling comprising: a tubular body provided with at least one socket having an interior thread and retaining internally a grab ring and a demount collar having a contact surface to press against the teeth of the grab 5 ring to push them from a normal position to a demounting position; wherein the demount collar is provided with an external thread corresponding to the interior thread of the socket, such that screwing the demount collar inwards with respect to the tubular body presses the contact surface against the teeth of the grab ring to move them to the demounting position and unscrewing the

10 demount collar outwards with respect to the tubular body relieves pressure against the teeth and allows them to move into a normal, gripping, position;

wherein the demount collar is provided with one or more axially oriented connection features for connection to one or more corresponding axially oriented connection features of a tool, such that rotation of the tool connected

15 to the demount collar effects rotation of the demount collar; and wherein the one or more connection features of the demount collar are recesses, notches or holes in its axially outer face.

20

3. A push-fit pipe coupling according to claim 1 or 2 wherein the demount collar is provided with at least two connection features spaced around the circumference of its axial end.

4. A push-fit pipe coupling according to any preceding claim wherein the connection features are notches extending from the outer circumferential surface of the demount collar.

5. A push-fit pipe coupling according to any preceding claim wherein the 5 demount collar is configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 10mm.

CD

CM

O

6. A push-fit pipe coupling according to any preceding claim wherein the demount collar is configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 5mm

10

7. A push-fit pipe coupling according to any preceding claim wherein the demount collar is configurable such that with the grab ring in the normal position, it extends axially from the end of the socket by no more than 3mm

8. A push-fit pipe coupling according to any preceding claim wherein the demount collar is configurable such that with the grab ring in the normal

15 position, it extends axially from the end of the socket by no more than 1mm.

9. A push-fit pipe coupling according to any preceding claim wherein the demount collar is flush with, or arranged entirely internally of the end of the socket when the grab ring is in its normal position.

10. A push-fit pipe coupling according to any preceding claim further comprising

20 a sealing ring.

11. A push-fit pipe coupling according to claim 10 further comprising a protection ring separating the sealing ring and the grab ring.

12. A push-fit pipe coupling according to any preceding claim wherein the tubular body comprises a separate socket portion and body portion.

13. A push-fit pipe coupling according to claim 12 wherein the socket portion snap-fits to the body portion.

5

14. A push-fit pipe coupling according to claim 12 or 13 when dependent on claim

11 wherein the protection ring snap fits to the socket portion or the body portion.

CD

CM

O

15. A push-fit pipe coupling according to any of claims 11,14 or either 12 or 13 when dependent on claim 11, wherein the coupling comprises a support ring 10 and the grab ring is sandwiched between the protection ring and the support ring.

16. A push-fit pipe coupling according to any preceding claim wherein the tubular body comprises a threaded insert to provide the internal thread.

17. A push-fit pipe coupling according to claim 16 when dependent directly or 15 indirectly on claim 12 wherein the threaded insert is configured to co-operate with the protection ring to provide a support for the grab ring and to retain the sealing ring.

18. A kit of parts comprising a push-fit pipe coupling according to any of claims 1 to 17 and demount tool for use with the demount collar of such a pipe fitting,

20 the tool comprising a part-ring provided with one or more axially oriented connection features for connection to one or more corresponding axially oriented connection features of the demount collar.

19. A kit according to claim 18 wherein the one or more connection features of the demount tool are projections.

20. A kit according to claim 18 or 19 wherein the demount tool is provided with two, or three connection features.

5

21. A kit according to any of claims 18 to 20 wherein the connection features of the demount tool are circumferentially spaced around the part-ring.

22. A kit according to claim 21 wherein the connection features of the demount tool are equally circumferentially spaced around the part-ring.

CD

CM

O

23. A kit according to any of claims 18 to 22, wherein the demount tool comprises

10 radially extending arms.

24. A method of demounting a grab ring from a pipe in a pipe coupling according to any of claims 1 to 17 comprising introducing a demount tool according to any of claims 18 to 23 over the pipe, engaging the connection features of the demount tool with the connection features of the demount collar and turning the demount tool so as to push the teeth of the grab ring into a demounting position.