GB2299388A

GB2299388A - Gripping ring for a pipe coupling

Info

Publication number: GB2299388A
Application number: GB9506665A
Authority: GB
Inventors: Paul Joseph Morrow
Original assignee: Victaulic Co PLC
Current assignee: Victaulic Co PLC
Priority date: 1995-03-31
Filing date: 1995-03-31
Publication date: 1996-10-02
Anticipated expiration: 2015-03-31
Also published as: GB9506665D0; GB2299388B

Abstract

The ring is of generally frustoconical form and has inclined radially inner 5 and outer 6 faces and radially inner 7 and outer 8 edges, the radially inner edge 7 being a gripping edge for gripping a pipe, the gripping ring having a circumferential break to enable it to contract when compressed; the ring 4 has integrally formed therewith a supporting limb 9 which extends outwardly from the radially outer face 6 from a location between the radially inner 7 and outer 8 edges to approximately the same radial extent as the said radially outer edge 8. A pipe clamp comprises a sleeve for encircling and clamping about a pipe; and clamping means for clamping the sleeve about the pipe; the sleeve having a radially inwardly extending flange at a pipe-receiving axial end thereof, a sealing gasket disposed within the sleeve and extending circumferential around the radially inner wall thereof for sealing against said pipe; and the gripping ring.

Description

GRIPPING RING FOR A PIPE COUPLING This invention relates to a gripping ring for a pipe coupling, and to a pipe coupling incorporating the gripping ring.

It is to be understood that by the expression "pipe" as used herein, is meant any pipe-like member including pipes as such, as well as pipe fittings such as "T"junctions, elbows, bends, reducers and valve inlets, for example.

In a first aspect the invention provides a gripping ring for use in a pipe coupling; the gripping ring being of generally frustoconical form and having inclined radially inner and outer faces and radially inner and outer edges, the radially inner edge being a gripping edge for gripping a pipe, the gripping ring having a circumferential break to enable it to contract when compressed; characterised in that the gripping ring has integrally formed therewith a supporting limb which extends outwardly from the radially outer face from a location between the radially inner and outer edges to approximately the same radial extent as the said radially outer edge.

In a second aspect, the invention provides a pipe clamp comprising a sleeve for encircling and clamping about a pipe; and clamping means for clamping the sleeve about the pipe; the sleeve having a radially inwardly extending flange at a pipe-receiving axial end thereof; a sealing gasket disposed within the sleeve and extending circumferentially around the radially inner wall thereof for sealing against said pipe; and a gripping ring disposed axially between the gasket and the flange, the gripping ring being of generally frustoconical form, and having inclined radially inner and outer faces and radially inner and outer edges; the radially inner edge being a gripping edge for gripping a pipe inserted into the sleeve, and the radially outer edge being arranged to abut against the radially inner wall of the sleeve, the gripping ring having a circumferential break to enable it to contract when compressed; characterised in that the gripping ring has integrally formed therewith a supporting limb which extends outwardly from the radially outer face from a location between the radially inner and outer edges to approximately the same radial extent as the said radially outer edge, so as to abut against the radially inner wall of the sleeve.

According to one embodiment of the invention, the gripping ring has a continuous gripping edge, but it may alternatively have a discontinuous gripping edge, i.e. the gripping edge may be constituted by a plurality of circumferentially spaced discrete gripping edges or teeth.

The supporting limb can extend continuously around the circumference of the gripping ring or it can take the form of a plurality of circumferentially spaced apart discrete supporting limbs.

An annular spacer or thrust washer may optionally be disposed axially between the gripping ring and the gasket.

The invention will now be illustrated, but not limited, by reference to the specific embodiments shown in the accompanying drawings of which: Figure 1 is a schematic longitudinal section through part of the pipe coupling according to one embodiment of the invention; Figure 2 is an enlarged sectional elevation of the grip ring illustrated in Figure 1; Figure 3 is a view from one side of the grip ring shown in Figures 1 and 2; Figure 4 is a sectional elevation along line I-I in Figure 3; Figure 5 is a view from one side of a grip ring according to a second embodiment of the invention; Figure 6 is a view along line II-II in Figure 5; and Figure 7 is an enlarged view of the portion of the grip ring marked A in Figure 6.

Referring now to the drawings, it can be seen that a pipe coupling sleeve according to one embodiment of the invention comprises a cylindrical casing 1 which in this embodiment can be formed from stainless steel. The casing has a circumferential break or discontinuity such that in appearance it may be considered to have a C-shape in crosssection. The two limbs of the C-shape are provided with a formation enabling clamping bolts to be attached thereto to allow the pipe clamp of the invention to be tightened down on to a pipe inserted therein. A bridging plate (not shown) is provided in order to bridge the circumferential break so as to prevent gasket extrusion through the break under pressure and to maintain gasket pressure around the full circumference of the joint.Such clamping arrangements, which are shown in, for example, EP-A0211158, EP-A-447955, and WO-A-8807644, to name but a few examples, are wholly conventional and need not be discussed in any detail here.

The axial ends of the casing 1 turn inwardly to define radially inwardly extending circumferential flanges 2. The casing 1 is lined with a gasket 3 formed from an appropriate elastomeric material.

Disposed axially between the gasket 3 and the flange 2 is a gripping ring 4 which has a circumferential break 4a to allow it to contract to grip a pipe wall in use. The gripping ring 4 is illustrated in more detail in Figures 2, 3 and 4. An annular thrust washer (not shown) may optionally be disposed axially between the gripping ring 4 and gasket 3 so as to give a measure of protection against potential damage by the gripping ring.

As shown in Figures 2 and 4, the gripping ring is generally frustoconical in form and has an inclined radially inner face 5, an inclined radially outer face 6, a radially inner edge 7 and a radially outer edge 8.

Radially inner edge 7 has a sharp edge to enable it to bite into the surface of a pipe whilst radially outer edge 8 is blunter and is arranged to abut against the radially inner surface 1A of the casing. The inner edge 7 may have a continuous sharp edge or an interrupted sharp edge.

Interruptions may be formed in the continuous section by use of a knurled roller of other appropriate means. At a location 10 approximately midway between the radially inner edge 7 and the radially outer edge 8, and extending outwardly from the radially outer surface 6 is limb 9 which in this embodiment extends circumferentially along the entire length of the gripping ring 4. As will be appreciated, however, limb 9 need not be continuous but could exist as a plurality of discrete spaced apart limbs.

Limb 9 abuts against the radially inner wall 1A of the casing and serves to stiffen the gripping ring and prevent excessive deformation of the gripping ring under clamping conditions.

The gripping ring of Figures 1 to 4 can be formed by cold rolling a section of steel strip to provide it with the appropriate cross-section, rolling the strip into a ring and then subjecting it to hardening. As an alternative to cold rolling, the gripping ring may be fabricated by hot rolling or a combination of hot rolling and cold rolling.

In the embodiment shown in Figure 1 both axial ends of the coupling sleeve are identical, each having a gripping ring disposed therein, but this need not be the case. For example, one end could be provided with an alternative coupling mechanism, or could form part of a piece of apparatus or equipment to which a pipe may be connected, for example a valve or the like.

In use, a pipe P, shown in phantom, is inserted into the pipe coupling in standard fashion and the clamping arrangement (not shown) is tightened to reduce the diameter of the pipe coupling forcing the gripping edge 7 radially inwardly and into contact with the outer wall of the pipe P. Thanks to the stiffening limb 9, the gripping ring is better able to resist radially outward deformation of the gripping edge 7 with the result that a much better grip on the pipe surface is obtained.

When the pipe coupling is subjected to internal pressurisation, the tendency of the pipe end P to pull out of the coupling is prevented due to the gripping ring being firmly embedded in the pipe.

An alternative gripping ring for use in the pipe coupling of Figure 1 is illustrated in Figures 5 to 7.

Thus, the gripping ring has a radially inner surface 15, a radially outer surface 16, a radially inner edge 17 which constitutes the gripping edge, a radially outer edge 18, and has a limb 19 extending outwardly from a location 20 on the radially outer surface to approximately the same radial extent as the edge 18. In this embodiment, unlike the embodiment shown in Figure 1, the limb 19 is formed by cutting or stamping out a finger of metal from a frustoconical strip and bending it to the required angle.

The benefits of the gripping rings of the present invention are that they provide a firm positive gripping action whilst being simple to fabricate and light in weight.

It will readily be apparent that numerous modifications and alterations may be made to the embodiments shown in the accompanying drawings without departing from the principles underlying this invention, and all such modifications and alterations are within the scope of this Application.

Claims

1. A gripping ring for use in a pipe coupling; the gripping ring being of generally frustoconical form and having inclined radially inner and outer faces and radially inner and outer edges, the radially inner edge being a gripping edge for gripping a pipe, the gripping ring having a circumferential break to enable it to contract when compressed; characterised in that the gripping ring has integrally formed therewith a supporting limb which extends outwardly from the radially outer face from a location between the radially inner and outer edges to approximately the same radial extent as the said radially outer edge.

2. A gripping ring according to claim 1 which has a continuous gripping edge.

3. A gripping ring according to claim 2 which has a discontinuous gripping edge constituted by a plurality of circumferentially spaced discrete gripping edges or teeth.

4. A gripping ring according to any one of the proceeding claims wherein the supporting limb extends continuously around the circumference of the gripping ring.

5. A gripping ring according to any one of claims 1 to 3 wherein the supporting limb takes the form of a plurality of circumferentially spaced apart discrete supporting limbs.

6. A gripping ring substantially as described herein with reference to the accompanying drawings Figures 1 to 4.

7. A gripping ring substantially as described herein with reference to the accompanying drawings Figures 5 to 7.

8. A pipe clamp comprising a sleeve for encircling and clamping about a pipe; and clamping means for clamping the sleeve about the pipe; the sleeve having a radially inwardly extending flange at a pipe-receiving axial end thereof; a sealing gasket disposed within the sleeve and extending circumferentially around the radially inner wall thereof for sealing against said pipe; and a gripping ring disposed axially between the gasket and the flange, the gripping ring being of generally frustoconical form, and having inclined radially inner and outer faces and radially inner and outer edges; the radially inner edge being a gripping edge for gripping a pipe inserted into the sleeve, and the radially outer edge being arranged to abut against the radially inner wall of the sleeve, the gripping ring having a circumferential break to enable it to contract when compressed; characterised in that the gripping ring has integrally formed therewith a supporting limb which extends outwardly from the radially outer face from a location between the radially inner and outer edges to approximately the same radial extent as the said radially outer edge, so as to abut against the radially inner wall of the sleeve.

9. A pipe clamp according to claim 8 wherein the gripping ring is as defined in any one of claims 1 to 7.

10. A pipe clamp according to claim 8 or claim 9 wherein an annular spacer or thrust washer is disposed axially between the gripping ring and the gasket.