GB2166508A

GB2166508A - Pipe joints

Info

Publication number: GB2166508A
Application number: GB08526637A
Authority: GB
Inventors: Keith Millward
Original assignee: Paragon Plastics Ltd
Current assignee: Paragon Plastics Ltd
Priority date: 1984-11-05
Filing date: 1985-10-29
Publication date: 1986-05-08
Also published as: GB2166508B; GB8526637D0

Abstract

A pipe joint of the kind comprising a female pipe part for receiving a male pipe part and including a resilient sealing ring and a "grab" ring for locking the male pipe part within the female pipe part. So that the presence of the "grab" ring does not excessively increase the diameter of the joint, the "grab" ring is located in an undercut recess near the open end of the female pipe part and the "grab" ring is a split ring so that on assembly of the joint it has been able to be fed into the undercut recess with a spiral action. The sealing ring is in a separate recess. A tool with (a) pin(s) to force open the "grab" ring may be used to uncouple the joint. <IMAGE>

Description

SPECIFICATION Pipe joints The invention relates to pipe joints, particularly but not exclusively for use in water supply pipes.

Various kinds of pipe joints are known which comprise a female pipe part for receiving a male pipe part and also comprising a resilient sealing ring located in an undercut groove in the female pipe part, the sealing ring having a fluid sealing portion which is deflected radially outwards as the end of the male pipe part enters the sealing ring.

Pipe joints of the kind just described above may or may not be provided with means for retaining the male pipe part in the female pipe part. When such means are provided, they may comprise some form of "grab" ring located within or at the end of the female pipe part by means of a locking sleeve encircling the end of the female pipe part, the "grab" ring being actuated by manipulation of the locking sleeve. Consequently, the overall diameter of the joint may be considerably increased.

The object of the invention is to provide a pipe joint of the kind described with means for retaining the male pipe part in the female pipe part but without excessively increasing the diameter of the joint and which does not require any kind of manipulation to actuate the "grab" ring.

According to the invention, there is provided a pipe joint comprising a female pipe part for receiving a male pipe part and also comprising a resilient sealing ring and a so-called "grab" ring located in respective undercut grooves within the wall thickness of the female pipe part, the "grab" ring having a tapered external surface with engages a surface of complementary taper in the undercut recess in which the ring is located, the arrangement being such that when the male pipe part is urged out of the female pipe part, either by internal fluid pressure or by some other action, the "grab" ring is caused to ride down the internal taper and effectively grips the male pipe part, the "grab" ring being made of a material harder than that of which the male pipe part subsequently to be fitted to it is made, and being a split ring so that it has been able to be fed into the undercut recess near the open end of the female pipe part in which it is located with a spiral action. The "grab" ring will preferably be provided with angled internal surfaces presenting tooth formations, that it to say circumferentially extending ridge elements, for indenting the periphery of the male pipe part.

The female pipe part may have a plurality of apertures which extend from an end surface of said pipe part to the undercut groove in which the "grab" ring is located, the arrangement being such that respective unseating pins carried by an extraneous de-mounting tool can be caused to extend through said apertures and to act against the "grab" ring so that the latter is pushed back along the tapered surface of the undercut groove in which it is located and is caused to release the male pipe part.

According to another aspect of the invention, there is provided, in combination, a pipe joint as just described and a de-mounting tool by means of which the "grab" ring forming part of the joint can be acted upon to release the male pipe part, the de-mounting tool including a plate element for at least partially embracing the male pipe part and including also a plurality of unseating pins extending in parallel from a side face of the plate element and capable of extending through the apertures which extend from the end surface of the female pipe part of the joint to the undercut groove in which the "grab" ring is located. The plate element of the de-mounting tool may be formed by two substantially semi-circular parts hingedly connected together so that the tool can be fitted around the male pipe part.

Alternatively, the female pipe part may have an aperture which extends from an end surface of said pipe part to the undercut groove in which the "grab" ring is located, the arrangement being such that a ring spacer can be caused to extend through said aperture so that the opposite ends of the "grab" ring act against the opposite side surfaces of said ring spacer, the "grab" ring thereby being rendered inoperative to allow the male pipe part to be freely adjusted in position within the female pipe part until the ring spacer is removed to allow the "grab" ring to become operative.

According to a still further aspect of the invention, there is provided, in combination, a pipe joint as just described and a ring spacer by means of which the "grab" ring of the joint can be rendered inoperative to allow the male pipe part to be freely adjusted in position within the female pipe part.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a part sectional side view of a pipe joint embodying the invention, Figure 2 is a perspective view showing a "grab" ring being fitted in a female pipe part of the joint, Figure 3 is a view similar to Fig. 1 and illustrating a possible modification which will be referred to, Figure 4 is a view in the direction of arrow 4 in Fig. 3, and Figures 5 and 6 are views similar to Figs. 3 and 4 which illustrate a further possible modification.

Referring now to Fig. 1 of the drawings, the pipe joint there illustrated comprises a female pipe part 10 for receiving a male pipe part 12, said female pipe part being in the nature of a slightly enlarged sleeve butt-welded to a length of pipe of the same external and internal diameters as the male pipe part. Located in an undercut recess within a portion 14 of the female pipe part with a somewhat increased wall thickness is a resilient sealing ring 16, the latter having a fluid sealing portion which is deflected radially outwards as the end of the male pipe part enters the sealing ring. The sealing ring is made of a very soft and pliable rubber or synthetic rubber material so that of course, even though formed as a complete ring, it presents no problem when being fitted within the undercut groove.

Means which are provided for retaining the male pipe part in the female pipe part are constituted by a so-called "grab" ring 18 which is provided with angled internal surfaces presenting what in Fig. 1 appear to be tooth formations digging into the periphery of the male pipe part. The external surface of the "grab" ring is tapered, as shown, and engages a surface of complementary taper in a further undercut recess 20 near the open end of the portion 14 of the female pipe part. The arrangement is such that when the male pipe part is urged out of the female pipe part, either by internal fluid pressure or by some other action, the "grab" ring is caused to ride down the internal taper and effectively grips the male pipe part.

It will be understood that the "grab" ring is necessarily made of some reasonably hard material, that is to say of a material harder than that of which the male pipe is made.

Consequently, it cannot be flexed in the way in which the resilient sealing ring 16 can be flexed when fitting it within its undercut groove. For this reason the "grab" ring is a split ring so that, when being fitted within its undercut recess, it can be fed into it with a spiral action as indicated in Fig. 2. When the "grab" ring is in use and has been caused to ride down the internal taper of the undercut groove in which it is located, the gap between its ends will be reduced.

It will be understood that an important advantage of the pipe joint just described is that when the resilient sealing ring and the "grab" ring have been located in their respective grooves in the factory, they can be despatched to the distributor or user without risk of a screwthreaded or otherwise connected locking sleeve becoming detached and possibly lost. In addition the joint cannot easily be dismantled by unauthorised personnel before or after installation.

Referring now to Figs. 3 and 4 of the drawings, the pipe joint there illustrated is otherwise the same as that illustrated in Figs. 1 and 2 but has been modified so that it can receive a so-called de-mounting tool by means of which the "grab" ring can be caused to release the male pipe part. The de-mounting tool is generally indicated 22 in Fig. 3 and includes a plate element 24 at least partially embracing the male pipe part and including also three equally spaced unseating pins 26 which extend in parallel from a side face of the plate element. (It will be understood that the plate element could be of substantially horseshoe shape to enable it to be placed in position on the male pipe part of the joint with the three unseating pins equally spaced around the joint as shown.Alternatively, the plate element could be formed by two semicircular parts hingedly connected together so that the tool can be fitted around the male pipe part).

The modification to the joint itself to enable it to receive the de-mounting tool has involved the provision of three equally spaced apertures 28 extending from an end surface of the female pipe part to the undercut groove in which the "grab" ring is located. As best seen in Fig. 4, it will be seen that in this illustrated embodiment the apertures are constituted by slots which open from the interior of the female pipe part (but it will be understood that they could equally well have been constituted by three equally spaced drilled holes of appropriate size).

The arrangement is such that when the unseating pins of the de-mounting tool have been caused to extend through the apertures in the female pipe part, they can be caused to act against the "grab" ring so that the latter is pushed back along the tapered surface of the undercut groove in which it is located.

The male pipe part is thereby released.

In Figs. 5 and 6 there is illustrated a further possible modification of the previously described pipe joint. The pipe joint illustrated in Figs. 5 and 6 is again otherwise the same as that illustrated in Figs. 1 and 2 but has been modified so that it can receive a so-called ring spacer by means of which the "grab" ring of the pipe joint can be rendered inoperative to allow the male pipe part to be freely adjusted in position within the female pipe part. (This is a particularly advantageous feature in a repair "slip" coupler which may have to be moved about in this way to insert it in a pipe line).

The ring spacer illustrated is a headed key like element 30 of elongate rectangular section material. Consequently, the modification to the joint itself to enable it to receive the ring spacer has involved the provision of an aperture 32 of complementary shape which extends from an end surface of the female pipe part to the undercut groove in which the "grab" ring is located.

The arrangement is such that the ring spacer can be inserted in position before the pipe joint is used. The opposite ends of the "grab" ring thus act against the opposite side surfaces of said ring spacer, the "grab" ring thereby being rendered inoperative to allow the male pipe part to be freely adjusted in position within the female pipe part. When the ring spacer is subsequently removed, the "grab" ring is allowed to become operative and grips the male pipe part.

Various other modifications may be made and it will be understood that the invention may be employed in joints other than those including a socket butt welded to a pipe. It could for example be employed in Double Couplers, Tees, Elbows and the like. The socket could of course be connected to the pipe by means other than butt welding. It will of course be understood that the resilient sealing ring need not necessarily be constituted by a lip seal of the kind illustrated. In smaller diameter joints, for example, it may be constituted by an O-ring.

Claims

1. A pipe joint comprising a female pipe part for receiving a male pipe part and also comprising a resilient sealing ring and a socalled "grab" ring located in respective undercut grooves within the wall thickness of the female pipe part, the "grab" ring having a tapered external surface which engages a surface of complementary taper in the undercut recess in which the ring is located, the arrangement being such that when the male pipe part is urged out of the female pipe part, either by internal fluid pressure or by some other action, the "grab" ring is caused to ride down the internal taper and effectively grips the male pipe part, the "grab" ring being made of a material harder than that of which the male pipe part subsequently to be fitted to it is made, and being a split ring so that it has been able to be fed into the undercut recess near the open end of the female pipe part in which it is located with a spiral action.

2. A pipe joint according to claim 1, in which the "grab" ring is provided with angled internal surfaces presenting tooth formations, that its to say circumferentially extending ridge elements, for indenting the periphery of the male pipe part.

3. A pipe joint according to either one of the preceding claims, in which the female pipe part has a plurality of apertures which extend from an end surface of said pipe part to the undercut groove in which the "grab" ring is bated, the arrangement being such that respective unseating pins carried by an extraneous de-mounting tool can be caused to extend through said apertures and to act against the "grab" ring so that the latter is pushed back along the tapered surface of the undercut groove in which it is located and is caused to release the male pipe part.

4. In combination, a pipe joint according to claim 3 and a de-mounting tool by means of which the "grab" ring forming part of the joint can be acted upon to release the male pipe part, the de-mounting tool including a plate element for at least partially embracing the male pipe part and including also a plurality of unseating pins extending in parallel from a side face of the plate element and capable of extending through the apertures which extend from the end surface of the female pipe part of the joint to the undercut groove in which the "grab" ring is located.

5. The combination claimed in claim 4, in which the plate element of the de-mounting tool is formed by two substantially semi-circular parts hingedly connected together so that the tool can be fitted around the male pipe part.

6. A pipe joint according to either one of claims 1 and 2, in which the female pipe part has an aperture which extends from an end surface of said pipe part to the undercut groove in which the "grab" ring is located, the arrangement being such that a ring spacer can be caused to extend through said aperture so that the opposite ends of the "grab" ring act against the opposite side surfaces of said ring spacer, the "grab" ring thereby being rendered inoperative to allow the male pipe part to be freely adjusted in position within the female pipe part until the ring spacer is removed to allow the "grab" ring to become operative.

7. In combination, a pipe joint according to claim 6 and a ring spacer by means of which the "grab" ring of the joint can be rendered inoperative to allow the male pipe part to be freely adjusted in position within the female pipe part.

8. A pipe joint constructed, arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.