GB2532809A

GB2532809A - Seal

Info

Publication number: GB2532809A
Application number: GB1506030.4A
Authority: GB
Inventors: Nicholas Whiteley Paul
Original assignee: Pegler Yorkshire Group Ltd
Current assignee: Aalberts Integrated Piping Systems Ltd
Priority date: 2015-04-09
Filing date: 2015-04-09
Publication date: 2016-06-01
Also published as: GB201506030D0; GB2538160A; WO2016162674A1; GB201718476D0; GB2554009A; GB2554009B

Abstract

A sealing element 1 is provided on a ring. In some embodiments the ring on which the sealing element 1 is provided is a grab ring 2. Reconfigurable portions of the ring, such as teeth 11, depend from the sealing element 1 and extend radially inwardly. The reconfigurable portions 11 are arranged to be reoriented by insertion of a pipe 3, such that reorientation fo the reconfigurable portions 11 brings the sealing element 1 into engagement with the outer surface of the pipe 3.

Description

Technical Field of the Invention

The present invention relates to seals and especially, but not exclusively to seals attached to grab rings, as used in plumbing fittings for pipes. In particular the invention relates to a grab ring which includes a sealing element, or a sealing element held on another ring and reoriented by insertion of a pipe. The invention extends to pipe couplings incorporating such rings, to methods of coupling pipes using such rings and a method of forming such a ring.

Background to the Invention

Traditionally push fit plumbing fittings use an o-ring as a sealing element to create a seal between the fitting and the pipe (or "tube"). This o-ring is normally held in the socket of the fitting perpendicularly to the axis of the pipe, with the pipe being retained by a grab ring. Other components support and separate these key functional parts.

As will be understood by those in the art, a grab ring is a ring normally formed of metal and normally a complete ring, with no breaks, which is formed with teeth or the like which grab the exterior surface of the pipe. Prior to insertion of a pipe, these grab rings are held in a socket of a pipe connector, such that the teeth extend (radially) inwards, such that their inner ends define a smaller circumference than that of the pipe that is to be introduced into the coupling. Prior to insertion of a pipe, the teeth are normally arranged at an angle substantially perpendicular to the axis of the pipe coupling, or angled slightly inwardly (i.e. in the direction of insertion of a pipe). When a pipe is introduced into the coupling, the teeth are reoriented (e.g. bent) axially inward (in the direction of insertion of the pipe), so as to bite into the outer surface of the pipe and oppose axially outward movement of the pipe in the direction opposite to insertion).

A problem, which is especially acute when metal pipes are used, is that when the pipe is cut to length, the cut edge is left sharp, and will often have a burr on it. Pipes formed of softer material such as copper are relatively easy to clean up and deburr, but the harder, e.g. steel, pipes require special tools and regardless of the material, additional time is spent correctly preparing the pipe for inserting into the fitting. If an incorrectly prepared pipe is pushed into the fitting then there is an increased chance that as the sharp pipe contacts the soft sealing element (typically an o-ring) damage will occur, usually in the form of a section of the seal being cut away. Often this damage will create a leak path allowing the fluid in the plumbing system to escape, causing the fitting to have to be removed and replaced.

The present invention seeks to at least partially overcome or alleviate this problem.

Summary of the Invention

According to one aspect of the invention, there is provided a grab ring comprising a sealing element.

By providing a sealing element on the grab ring itself, the grab ring can grab and guide a pipe, to avoid the end of the pipe contacting (and potentially damaging) the sealing element.

Preferably the sealing element comprises a sealing ring.

Preferably the grab ring comprises at least one portion, which is arranged to be reoriented by insertion of a pipe and preferably sealing element is arranged on the grab ring, such that reorientation of the at least one portion of the grab ring brings the sealing element to engagement with the outer surface of a pipe.

In a second aspect of the invention, there is provided a ring comprising an annular sealing element having at least one reconfigurable portion depending therefrom and extending radially inwardly, the reconfigurable portion being arranged to be reoriented by insertion of a pipe, such that reorientation of the reconfigurable portion brings the sealing element into engagement with the outer surface of the pipe.

Whilst the combination of both the gripping function of a grab ring and the sealing function of (e.g. an 0-ring) in one component, according to the first aspect of the invention, is a very elegant solution to the problem, the ring, which is reoriented by insertion of a pipe, to bring the sealing element into engagement with the outer surface of the pipe, need not necessarily be a grab ring, i.e. the ring may not also function to hold the pipe against axial movement out of a coupling. Thus, in the second aspect, the ring is not limited to a grab-ring, but simply to a ring which carries out the same function in relation to the sealing element.

Whereas a grab ring is typically (and preferably) metal, the ring of the second aspect of the invention may be non-metal, e.g. plastic. A separate (e.g. standard) grab ring may also be required to retain the pipe, but such a grab ring could be arranged between the sealing ring of the second aspect of the invention and the mouth of the pipe coupling, such that it is entirely separated from the fluid inside the system. This would be particularly useful if the fluid was corrosive to the (typically metal) teeth of the grab ring.

Preferably the at least one reconfigurable portion of the grab ring of the first aspect, or sealing ring of the second aspect which is arranged to be reoriented is a plurality of radially inwardly extending teeth.

Preferably the grab ring of the first aspect, or sealing ring of the second aspect is operable to move from a relaxed position, in which it does not engage a pipe, to a deployed position, in which at least one reconfigurable portion is reoriented to (in the case of a grab ring) grab a pipe and preferably the radially inner surface of the sealing element defines a smaller diameter in the deployed position than in the relaxed position.

Preferably the radially outer surface of the sealing element is arranged to be compressed against the radially inner surface of a pipe coupling when the reconfigurable portion is reoriented. Preferably the radially outer surface of the sealing element defines a larger diameter in the deployed position than in the relaxed position.

I5 Preferably the grab ring of the first aspect, or sealing ring of the second aspect comprises a body portion from which the at least one reconfigurable portion depends and to which the sealing element is attached and preferably the body is arranged such that it is reoriented by the insertion of a pipe into the grab ring of the first aspect, or sealing ring of the second aspect.

Preferably a pipe coupling is provided comprising a grab ring of the first aspect, or sealing ring of the second aspect as defined above, the coupling comprising a mouth into which, in use, a pipe is introduced axially.

Preferably the grab ring of the first aspect, or sealing ring of the second aspect is arranged in the pipe coupling with the reconfigurable portion angled radially and axially inwardly with respect to the axis along which, in use, a pipe is introduced, such that when a pipe is introduced, the reconfigurable portion is reoriented to a greater axially inward configuration.

Preferably the sealing element is a resilient frustoconical sealing ring having a long axis (along the length of the conical section) and a short axis (perpendicular to the length of the conical section) in the relaxed position, prior to introduction of a pipe, and preferably the inner diameter of the frustoconical sealing ring is located closer to the respective mouth of the coupling than the outer diameter of the frustoconical sealing ring.

Preferably insertion of a pipe into the ring causes the frustoconical sealing ring to be deformed such that the inner diameter of the ring is smaller and the outer diameter is larger, so as to seal with the outer diameter of the pipe and the inner diameter of the coupling.

In a third aspect of the invention, there is provided a method of coupling a pipe comprising introducing a pipe into a pipe coupling comprising a grab ring according to the first aspect of the invention or sealing ring of the second aspect of the invention.

Preferably as the pipe is introduced into the coupling a reconfigurable portion of the grab ring of the first aspect, or sealing ring of the second aspect is reoriented and the sealing element is deforms so as to form a seal between the pipe and the coupling.

In a fourth aspect of the invention there is provided a method of forming a grab ring comprising an integral sealing element, the method comprising overmoulding a sealing element onto a grab ring.

Preferably the method comprises overmoulding with an elastomer, to form an elastomeric sealing element.

The grab ring and the sealing element of the fourth aspect of the invention may have any or all of the preferred features of the first aspect of the invention.

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 la shows a lateral cross sectional view of a part-formed grab ring according to the invention; Figure lb shows an isometric view of the part formed grab ring of figure 1; Figure 2a shows a lateral cross sectional view of a grab ring according to the invention; Figure 2b shows an isometric view of the grab ring of figure 2a; Figure 3a shows a cross sectional view through part of the grab ring of figures 2a and 2b, in a relaxed state; Figure 3b shows a cross sectional view through part of the grab ring of figures 2a to 3a in a deployed state; Figure 4 shows an isometric part-exploded cross section of a first embodiment of a part-formed pipe coupling incorporating the grab ring of figures 2a to 3b; Figure 5 shows an isometric part-exploded cross section of a second embodiment of a pipe coupling incorporating the grab ring of figures 2a to 3b; Figure 6 7 Figure 7 shows an isometric part-exploded cross section of a third embodiment of a pipe coupling incorporating the grab ring of figures 2a to 3b; shows an isometric part-exploded cross section of a fourth embodiment of a pipe coupling incorporating the grab ring of figures 2a to 3b; Figures 8a-8d show a series of lateral cross sections a pipe being inserted into the pipe coupling of figure 7; and Figure 9 shows an isometric part-exploded cross section of a first embodiment of a part-formed pipe coupling incorporating a conventional grab ring and a sealing ring according to the invention.

With reference to figures 2a and 2b, a grab ring 1 is provided with a sealing element 2 around its circumference.

Figures la and lb show a part-formed grab ring 1 according to the invention, which, as is usual, is formed (e.g. pressed) from a resilient metal, so as to have a planar annular outer body 10, from which a series of teeth 11 depend. In this embodiment, there are eighteen teeth 11, which constitute a reconfigurable portion of the grab ring 1. The teeth 11 extend radially inwardly from the body 10 of the grab ring 1 and extend out of the plane of the body 10, at an angle thereto. The shape and number of teeth 11, as well as the angle (if any) at which they extend relative to the body 10 may of course be chosen by those skilled in the art in accordance with the requirements of the grab ring 1.

As shown in figures 2a, 2b, 3a and 3b, when fully formed, by overmoulding, an elastomeric sealing element 2 covers the entire body portion 10 of the grab ring 1. The elastomeric sealing element 2 is also ring shaped and somewhat frustoconi cal, having a substantially triangular cross section (with rounded corners) and a radially inner edge 20 offset axially from the radially outer edge 21. Whilst the teeth 11 extend out of the plane of the body 10 of the grab ring in one axial direction, the offset of the frustoconical elastomeric sealing element 2 is such that it extends from the radially outer edge 21 to the radially inner edge 20 in the opposite axial direction. Both the radially inner edge 20 and the radially outer edge 21 of the elastomeric sealing element 2 are rounded.

The grab rings of figures 2a to 3b are used in pipe couplings and a first embodiment of an exemplary coupling 3 is shown in figure 4. The pipe coupling 3 of figure 4, which may for example be formed of a metal, such as copper, is a straight pipe connector for joining two pipes (not shown, but for example for use in domestic water systems), in a fluid tight manner, along the same axis. Accordingly, the pipe coupling 3 is a substantially cylindrical tube with axially opposing sockets 31 which together define a through passage and receive respective pipes. Figure 4 shows the left hand socket 31 only part formed, with various parts exploded, for ease of understanding. Between the sockets 31, an end-stop 32 is formed, as a radially inwardly extending circumferential ridge against which the free ends of the pipes, in use, abut. Axially outwardly, each side of the end stop 32, a circumferential bulge 33 is formed (shown part formed on the left hand side of the drawing), so as to define a region of greater diameter than the remainder of the sockets 31, which in use receive the pipe and correspond to the outer diameter thereof. The bulge on the part-formed left hand side of the pipe coupling 3 in figure 4 is shown part-formed, such that it remains of greater diameter to the mouth of the socket 31.

Of course, when fully formed, the bulges 33 are both as shown on the right hand side of the figure, and have an area of normal diameter (corresponding to the size of the pipe to be introduced), both axially inwardly and axially inwardly of the bulges 33.

Within the bulges, 33, grab rings I, comprising sealing elements 2 are provided. The teeth 11 of each grab ring 1 extend radially inward and slightly axially inward. Each grab ring 1, is sandwiched in the bulge between an axially inner support 34 and an axially outer support 35. The supports 34, 35 may be formed of plastic, brass or steel (depending on the materials used elsewhere in the coupling and, at least for the inner support 34, depending on any chemical resistance properties required). Each of the supports 34, 35 is formed with a generally triangular cross section designed to conform with the shape of the bulge, the shape of the pipe, which will be inserted through the supports 34, 35 and with the shape of the sealing element 2 which rests between the supports 34, 35. The axially outermost edge of the inner support 34 acts as a fulcrum about which the grab ring 1 pivots when a pipe is introduced into the coupling 3. Accordingly, it is rounded to aid this pivoting motion. The radially inner face of the inner support is angled to allow the teeth 11 to be opened fully as a pipe is inserted. The radially innermost surface ofthe outer support 35 acts as a pipe guide during insertion of a pipe, to help keep the pipe centrally located and away from the seal; once the pipe is inserted and the system is pressurised, the axially inner face of the outer support 35 supports the axially outer face of the sealing element 2, helping to prevent the seal from being deformed by internal pressure and allowing fluid to escape. Accordingly, it is formed with a concave shape which conforms with the adjacent face of the sealing element 2.

To form the pipe coupling 3 of the first embodiment, with the supports 34,35 and grip ring I located in the bulges 33, the pipe coupling is initially formed with flared ends 36, and the inner support 34, grip ring 1 and outer support 35 are introduced into the flared part. The ends are then squeezed radially inward (axially outward ofthe region of the bulge 33) to reduce the mouth of the socket to the appropriate diameter (such that its inner diameter corresponds with the outer diameter of a pipe to be introduced thereto).

Figure 5 shows a second embodiment of an exemplary pipe coupling 4 including the grab rings 1 of figures 2a to 3b. The pipe coupling 4 of figure 5, may for example be formed of a plastics material, e.g. PVDF (polyvinylidene fluoride) and again is a straight pipe connector for joining two pipes (not shown) along the same axis. Accordingly, the pipe coupling 4 is a substantially cylindrical tube with axially opposing sockets 41 for receiving respective pipes. Figure 4 shows the left hand socket 41 only part formed, with various parts exploded, for ease of understanding. Between the sockets 41, an end-stop 42 is formed, against which the free ends of the pipes, in use, abut. Towards the axial outer ends of each socket 41, the coupling comprises a flared portion 43 having an increasing diameter. The flared portion 43 is formed with a tubular region 44 of larger diameter at each free end of the coupling 4 and an external thread is formed on the tubular region. An axially extending circumferential projection 45 is formed radially inwardly of the larger diameter tubular region 44, so as to define a circumferential groove 46, into which the sealing element 2 of the grab ring 1 fits.

An annular end cap 47 (having an internal thread) is screwed onto the external thread of each larger diameter tubular region 44 and tapers to form a mouth 48 of slightly larger diameter than the internal diameter of the remainder of the coupling (the end caps may be formed for example of nylon 6, with a high percentage of glass filler (e.g. 30%).

An outer support 49 is sandwiched outside (axially) each grab ring 1 and inside the respective end cap 47, to hold the grab rings 1 in place -just as in the first embodiment, this support has a radially inner surface to guide and centralise a pipe to avoid it contacting the sealing element 2 and a concave axially inner surface to conform with the shape of the sealing element 2. Just as a shape similar to that of the support of the first embodiment was formed by the projection 45 in the flared portion 43 of the pipe coupling 4, the shape of the outer support 49 could be formed in the end cap 47, as an alternative.

The teeth 11 of each grab ring 1 extend radially inward and slightly axially inward.

To form the pipe coupling 4 of the second embodiment, the grip ring I is located in the groove 46, the support 49 is located outside (axially) the grip ring, and the end caps 48 are screwed onto the thread of the larger diameter tubular region 44.

A third embodiment of an exemplary coupling 5 is shown in figure 6. The pipe coupling 5 of figure 6, which may for example be formed of a metal, such as copper, is a straight pipe connector for joining two pipes (not shown) along the same axis. Accordingly, the pipe coupling 5 is a substantially cylindrical tube with axially opposing sockets 51 for receiving respective pipes. Figure 6 shows the left hand socket 51 only I 5 part formed, with various parts exploded, for ease of understanding. Between the sockets 51, an end-stop 52 is formed, as an radially inwardly extending circumferential ridge against which the free ends of the pipes, in use, abut. Axially outwardly, each side of the end stop 52, the pipe coupling flares outward so as to have a frustoconical portion, from which a larger diameter tubular portion 54 extends. Each larger d am eter tubular portion 54 terminates with a circumferential bead of even greater diameter. This flared portion 53 and larger diameter tubular portion 54 defines a region of greater diameter than the remainder of the sockets 51, which in use receive the pipe and correspond to the outer diameter thereof A snap-fit end cap 56 is provided at each end of the pipe coupling 5, which clips over the bead 54 and extends radially inwardly. Again, the end cap 56 may be formed of glass reinforced plastic, such as nylon 6 with 30% glass filler. The axially inside edge of each snap-fit end cap 56 is provided with an axially outwardly extending circumferential groove 57, which conforms to the shape of the outside edge of the sealing element 2 of the grab ring 1 which is held in the region of greater diameter. The teeth 11 of each grab ring I extend radially inward and slightly axially inward. Each grab ring 1, is sandwiched in the bulge between an axially inner support 58 and the respective end cap 56. The support 56 is formed with a generally triangular cross section designed to conform with the shape of the frustoconical portion 53, the shape of the pipe, which will be inserted into the pipe coupling 56 and with the shape of the sealing element 2 which rests between the support 56 and the end cap 57.

To form the pipe coupling 5 of the third embodiment, with each support 58 and grip ring 1 located in the respective region of greater diameter, the end cap is simply clipped over the bead 55 to secure the grip ring in position.

A fourth embodiment of a pipe coupling, which may be considered a hybrid of the other couplings, is shown in figure 7, and also, of course, incorporates a pair of grab rings of figures 2a to 3b. The pipe coupling 6 of figure 7, which may for example be formed of essentially a metal, such as copper, is a straight pipe connector for joining two pipes (not shown, but for example for use in domestic water systems), in a fluid tight manner, along the same axis. Accordingly, the pipe coupling 6 is a substantially cylindrical tube with axially opposing sockets 61 for receiving respective pipes. Figure 7 shows the left hand socket 61 only part formed, with various parts exploded, for ease of understanding. Between the sockets 61, an end-stop 62 is formed, as an radially inwardly extending circumferential ridge against which the free ends of the pipes, in use, abut. Axially outwardly, each side of the end stop 62, a circumferential bulge 63 is formed (shown part formed on the left hand side of the drawing), so as to define a region of greater diameter than the remainder of the sockets 61, which in use receive the pipe and correspond to the outer diameter thereof The bulge 63 on the part-formed left hand side of the pipe coupling 5 in figure 7 is shown part-formed, such that it remains of greater diameter to the mouth of the socket 61. Of course, when fully formed, the bulges 63 are both as shown on the right hand side of the figure, and have free end 64 of intermediate diameter, larger than the size of the pipe to be introduced, but smaller than the widest part of the bulge 63.

Within the bulges, 63, grab rings 1, comprising sealing elements 2 are provided. he teeth 11 of each grab ring 1 extend radially inward and slightly axially inward. Each grab ring 1, is sandwiched in the bulge 63 between an axially inner support 65 and an axially outer guide and support part 66. The supports 65 is formed with a generally triangular cross section designed to conform with the shape of the bulge, the shape of the pipe, which will be inserted through the support 65 and with the shape of the sealing element 2 which rests against the supports 65.

The axially outer support and guide part 66, on the other hand is a generally cylindrical shape, with an axially outer end having a mouth 67 provided with an axially outwardly extending taper to ease entry of a pipe (not shown), and an axially inner end having a radially outwardly extending projection 68, having a radially inner surface which continues the cylindrical bore for the pipe to fit into, an axially inner surface having a shape which conforms to hold the sealing element 2 of the grip ring 1, and an angled projecting surface to engage with the intermediate diameter portion of the bulge 63.

To form the pipe coupling 6 of the fourth embodiment, with the supports 65 and grip ring 1 located in the bulges 63, the pipe coupling is initially formed with flared ends 69, and the inner support 65, grip ring 1 and outer support and guide part 66 are introduced into the flared part 69. The free ends 64 are then squeezed radially inward (axially outward of the region of the bulge 63) to reduce the free ends 64 to the intermediate diameter, at which they clamp the intermediate guide and support piece which sandwiches the grip ring 1 and the inner support 65 in place.

The method of using the couplings 3,4,5,6 incorporating the grab ring 1 comprising a support element 2 is described with reference to figures 8a to 8d, which show a pipe coupling 6 of the fourth embodiment as described with reference to figure 7. However, the method is the same with each of the first to third embodiments of the couplings 3, 4, 5.

As shown in figure 8a, in the rest position, before a pipe 7 is introduced into the coupling 6, the grab ring 1 is seated in the bulge 63 (which is a region of greater diameter than the remainder of the sockets 61) with the teeth 11 angled radially inwardly and axially slightly inwardly (at an angle of between 30 and 45 degrees to the plane of the grab ring I, e.g. 32 degrees). In the rest (relaxed) position, the somewhat frustoconical ring shaped elastomeric sealing element 2 is angled radially inwardly and axially outwardly. The frustoconical ring shaped elastomeric sealing element 2 tapers towards the innermost edge 21 at an angle (in this particular embodiment) of 14 degrees, so in the rest position, the angle of one surface of the sealing element to the plane of the grab ring 1 is about 49 degrees, while the other surface is at an angle of 35 degrees..

The free end of a pipe 7 is then introduced into the mouth 67 of the coupling 6 until it abuts the teeth 11, which extend radially inwardly to define a diameter smaller than that of the pipe 7 (the pipe 7 being sized appropriately for the coupling, and having an outer diameter very slightly smaller than the inner diameter of the socket 61).

The pipe 7 is pushed further in, against the teeth 11, as shown in figure 8c and forces the teeth 11 to be reoriented to a deployed position, in which they extend radially inwardly to a greater extent than they extend axially inwardly (e.g. between 50 and 70 degrees to the plane of the grab ring and in this embodiment about 64 degrees to the plane of the grab ring I). This in turn reorients the body 10 of the grab ring 1 radially inwardly to a similar degree. However, the radially inner surface of the seal engages with the pipe 7 and the radially outer surface engages with the inner surface of the coupling 6, which deform it and prevent it from rotating to the same degree. Accordingly if the teeth 11 rotate by 32 degrees as set out above, one surface may rotate by 25 degrees to adopt an angle of about 24 degrees to the plane of the grab ring I, whilst the opposite surface adopts an angle of about 10 degrees to the plane of the grab ring. As a consequence of the body reorienting, the sealing element 2 which is overmoulded thereon is also reoriented, moving from the relaxed orientation shown in figure 3a to the deployed orientation shown in figure 3b. In the deployed position, the somewhat frustoconical ring shaped elastomeric sealing element 2 is angled radially inwardly and axially outwardly, but only at an angle of about 15 degrees to the plane of the grab ring 1).

As can be seen from comparison of figure 3b with figure 3a, this adoption of a more upright, deployed position means that the radially inner edge 20 has moved radially (and axially) inwardly and the radially outer edge 21 has moved radially (and axially) outwardly. The radially inward movement of the radially inner edge 20 (and consequent reduction of its inner diameter) brings the sealing element 2 into fluid-tight sealing engagement with the outside of the pipe 7, from a position in which it was very slightly spaced from the pipe to avoid being damaged by burrs etc. on the end of the pipe 7.

Simultaneously, the radially outer edge 21 has moved outward to adopt a larger diameter and now bears against the radially inside edge of the bulge 63 of greater diameter than the remainder of the socket 61 to complete the fluid tight seal.

The inner diameter of the sealing element 2 need not necessarily be spaced from the pipe 7 entirely upon introduction, although that is most desirable. If it is contacted slightly, but need not be displaced to the same extent as an ordinary o-ring, the force between the sealing element 2 and the pipe 7 is much reduced, so any burs etc are less likely to cause damage to the sealing element, and yet, because of the inward movement of the sealing element 2 in response to the rotation of the teeth 11, a good seal can still be achieved.

Once the grip ring 1 has been reoriented to form the seal, the user continues to push the pipe 7 into the socket 61 until the free end of the pipe 7 abuts the end stop 62.

Any attempt to remove the pipe is mitigated by the action of the teeth 11 of the grab ring 1, which, as with a conventional grab ring, bite into the outside of the pipe opposing such motion.

Of course, those skilled in the art will appreciate that the same action is carried out with another pipe (not shown) being introduced into the other socket 61 on the coupling 6, to complete the connection.

Figure 9 shows a fifth embodiment of a pipe coupling 8 comprising a sealing ring 9 according to the second aspect of the invention.

The sealing ring 9 of figure 9 takes a similar form to the grab ring I_ of the other embodiments. However, rather than being formed from a grab ring 1, the sealing ring 9 in the fifth embodiment is formed by over-moulding a sealing element 2, on a plastic ring. The plastic ring comprises similar a planar annular outer body 90, from which a series of teeth 91 depend. In this embodiment, the teeth 91 are broader than those of the grip ring, with a smaller gap between them. This provides a greater strength to the teeth 91, but (combined with the choice of material) means that they would not grip a pipe strongly and provide sufficient retaining ability to function as a grab ring. The teeth 91 constitute a reconfigurable portion of the sealing ring 9. The teeth 91 extend radially inwardly from the body 90 of the sealing ring 9 and extend out of the plane of the body 90, at an angle thereto. The shape and number of teeth 91, as well as the angle (if any) at which they extend relative to the body 90 may of course be varied.

When fully formed, by overmoulding, an elastomeric sealing element 2 covers the entire body portion 90 of the plastic ring. The elastomeric sealing element 2 is also ring shaped and somewhat frustoconical, having a substantially triangular cross section (with rounded corners) and a radially inner edge 20 offset axially from the radially outer edge 21. Whilst the teeth 91 extend out of the plane of the body 90 of the grab ring in one axial direction, the offset of the frustoconi cal elastomeric sealing element 2 i s such that it extends from the radially outer edge 21 to the radially inner edge 20 in the opposite axial direction. Both the radially inner edge 20 and the radially outer edge 21 of the elastomeric sealing element 2 are rounded.

The pipe coupling 8 of figure 9, which may for example be formed of a metal, such as copper, is a straight pipe connector for joining two pipes (not shown, but for example for use in domestic water systems), in a fluid tight manner, along the same axis. Accordingly, the pipe coupling 8 is a substantially cylindrical tube with axially opposing sockets 81 which together define a through passage and receive respective pipes. Figure 9 shows the left hand socket 81 only part formed, with various parts exploded, for ease of understanding. Between the sockets 81, an end-stop 82 is formed, as an radially inwardly extending circumferential ridge against which the free ends of the pipes, in use, abut. Axially outwardly, each side of the end stop 82, a circumferential bulge 83 is formed (shown part formed on the left hand side of the drawing), so as to define a region of greater diameter than the remainder of the sockets 81, which in use receive the pipe and correspond to the outer diameter thereof The bulge on the part-formed left hand side of the pipe coupling 8 in figure 9 is shown part-formed, such that it remains of greater diameter to the mouth of the socket 81. Of course, when fully formed, the bulges 83 are both as shown on the right hand side of the figure.

Within the bulges, 83, sealine rings 9, comprising sealing elements 2 are provided. The teeth 91 of each sealing ring 1 extend radially inward and slightly axially inward. Each sealing ring 9, is sandwiched in the bulge between an axially inner support 84 and an axially intermediate support 85. The supports 84, 85 may be formed of plastic, brass or steel (depending on the materials used elsewhere in the coupling and, at least for the inner support 84, depending on any chemical resistance properties required).

The inner support 84, is formed with a generally trapezoidal cross section designed to conform with the shape of the bulge, the shape of the pipe, which will be inserted through the supports 84, and with the shape of the sealing element 2 which rests between the axially inner support 84 and the axially intermediate support 85. The axially outermost edge of the inner support 85 acts as a fulcrum about which the sealing ring 9 pivots when a pipe is introduced into the coupling 8. Accordingly, it is rounded to aid this pivoting motion.

The intermediate support 85 is also of generally trapezoidal cross section, with a radially outer surface designed to conform with the shape of the bulge and an axially inner surface designed to conform with the shape of the sealing element 2. The axially outer surface, on the other hand, is shaped to conform with the axially inner surface of the body 95 of a conventional grab ring 96. Similarly, the radially innermost surface of the intermediate support 85 is angled to allow the teeth of the conventional grab ring 96 to move radially outward (and axially inward).

To sandwich the conventional grab ring 96 in position, an outer support 86 is also provided. The outer support 86 has a generally triangular cross section, but with an axially outwardly extending tubular guide section 87, which acts as a pipe guide during insertion of a pipe, to help keep the pipe centrally located and away from the seal. The axially inner face of the outer support 86 supports the axially outer face of the conventional grab ring 96, and the radially outer surface of the outer support 86 is angled so as to taper away outwardly, and to conform with the inside of the bulge 83.

To form the pipe coupling 8 of the fifth embodiment, with the supports 84, 85, 86 sandwiching the sealing ring 9 and the grip ring 96 in the bulges 83 (with the sealing ring located axially inwardly of the grip ring 96), the pipe coupling 8 is initially formed with flared ends 87, and the supports 84, 85, 86, and rings 9, 96 are introduced into the flared part 87. The ends 87 are then squeezed radially inward (axially outward of the region of the bulge 83) to reduce the mouth of the socket to the appropriate diameter, such that it holds all of the components in place.

Insertion of a pipe (not shown) is the same as for the earlier embodiments, with the difference that the teeth 91 of the sealing ring 9 are rotated by the pipe to cause the sealing element 2 to deform to a reoriented configuration, in which it seals against the outer surface of the pipe and the inner surface of the coupling 8, but the teeth 91 of the sealing ring 9 do not act to keep the pipe in place. Instead, the teeth of the conventional grab ring 96, which are also reoriented by the introduction of the pipe, retain the pipe in the coupling 8.

It will also be abundantly clear that whilst described in relation to a straight pipe coupling, the grab ring 1 with an integrated sealing element 2, or sealing ring 9 could also be used in various other joints, such as "tees", "elbows" and the like. Likewise, it will be appreciated that other elements of this specific description may be modified, just as an example, particular suitable angles have been defined in relation to the grab ring 1 and sealing element 2, but in light of this description, the skilled addressee, will be able to vary the angles as necessary.

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

Claims

CLAIMS1. A grab ring comprising a sealing element.
2. A grab ring according to claim 1 wherein the sealing element comprises a sealing ring.
3. A grab ring according to claim 1 or 2 comprising at least one reconfigurable portion, which is arranged to be reoriented by insertion of a pipe, wherein the sealing element is arranged on the grab ring, such that reorientation of the at least one reconfigurable portion of the grab ring brings the sealing element to engagement with the outer surface of a pipe.
4. A ring comprising an annular sealing element having at least one reconfigurable portion depending therefrom and extending radially inwardly, the reconfigurable portion being arranged to be reoriented by insertion of a pipe, such that reorientation of the reconfigurable portion brings the sealing element into engagement with the outer surface of the pipe 5. A ring according to claim 3 or 4 wherein the reconfigurable portion of the ring which is arranged to be reoriented is a plurality of radially inwardly extending teeth.A ring according to any of claims 3 to 5 which is operable to move from a relaxed position, in which it does not engage a pipe, to a deployed position.7. A ring according to claim 6 wherein the sealing element has a radially inner surface and the radially inner surface of the sealing element defines a smaller diameter in the deployed position than in the relaxed position.A ring according to claim 7 wherein the sealing element has a radially outer surface of the sealing element which arranged to be compressed against a radially inner surface of a pipe coupling when the reconfigurable portion is reoriented.9. A ring according to any of claims 6 to 8 wherein a radially outer surface of the sealing element defines a larger diameter in the deployed position than in the relaxed position.10. A ring according to any of claims 3 to 9 wherein the ring comprises a body portion from which the at least one reconfigurable portion depends and to which the sealing element is attached.11. A ring according to claim 10 wherein the body is arranged such that it is reoriented by the insertion of a pipe into the grab ring.12. A ring according to any of the preceding claims wherein the sealing element is a resilient frustoconical sealing ring.13. A pipe coupling comprising a ring according to any of the preceding claims, the coupling comprising a mouth into which, in use, a pipe is introduced axially.14. A pipe coupling according to claim 12 wherein the ring is arranged in the pipe coupling with a reconfigurable portion angled radially and axially inwardly with respect to the axis along which, in use, a pipe i is introduced, such that when a pipe is introduced, the reconfigurable portion is reoriented to a greater axially inward configuration.A pipe coupling according to claim 12 or 13 wherein the sealing element is a resilient frustoconical sealing ring having a long axis along the length of the conical section and a short axis perpendicular to the length of the conical section in the relaxed position, prior to introduction of a pipe, and the inner diameter of the frustoconical sealing ring is located closer to the respective mouth of the coupling than the outer diameter of the frustoconical sealing ring.16. A pipe coupling according to claim 15 wherein insertion of a pipe into the ring causes the frustoconical sealing ring to be deformed such that the inner diameter of the ring is smaller and the outer diameter is larger, so as to form a seal with the outer diameter of the pipe and the inner diameter of the coupling.17. A method of coupling a pipe comprising introducing a pipe into a pipe coupling comprising a ring according to any of claims 1 to 12.18. A method of coupling a pipe comprising introducing a pipe to a pipe coupling according to any of claims 13 to 16.19. A method of coupling a pipe according to claim 17 or 18 wherein as the pipe is introduced into the coupling a reconfigurable portion of the ring is reoriented and the sealing element is deforms so as to form a seal between the pipe and the coupling.20. A method of forming a grab ring comprising an integral sealing element, the method comprising overmoulding a sealing element onto a grab ring.21. A method of forming a grab ring according to claim 20 comprising overmoulding with an elastomer, to form an elastomeric sealing element.22. A method of forming a grab ring according to claim 20 or 21 wherein the grab ring is a ring according to any of claims 1 to 12.23. A grab ring, a ring comprising a sealing element, a pipe coupling, a method of coupling a pipe, or a method of forming a grab ring substantially as described herein with reference to the accompanying drawings.Amendments to the claims have been made as followsCLAIMS1. A grab ring comprising a sealing element.2. A grab ring according to claim 1 wherein the sealing element comprises a sealing ring.3. A grab ring according to claim 1 or 2 comprising at least one reconfigurable portion, which is arranged to be reoriented by insertion of a pipe, wherein the sealing element is arranged on the grab ring, such that reorientation of the at least one reconfigurable portion of the grab ring brings the sealing element to engagement with the outer surface of a pipe.cr) 10 4. A ring according to claim 3 wherein the reconfigurable portion of the ring whichTC\I is arranged to be reoriented is a plurality of radially inwardly extending teeth.
5. A ring according to claim 3 or claim 4 which is operable to move from a relaxed position, in which it does not engage a pipe, to a deployed position.
6. A ring according to claim 5 wherein the sealing element has a radially inner I5 surface and the radially inner surface of the sealing element defines a smaller diameter in the deployed position than in the relaxed position.A ring according to claim 6 wherein the sealing element has a radially outer surface of the sealing element which arranged to be compressed against a radially inner surface of a pipe coupling when the reconfigurable portion is reoriented.8. A ring according to any of claims 5 to 7 wherein a radially outer surface of the sealing element defines a larger diameter in the deployed position than in the relaxed position.A ring according to any of claims 3 to 8 wherein the ring comprises a body portion from which the at least one reconfigurable portion depends and to which the sealing element is attached.10. A ring according to claim 9 wherein the body is arranged such that it is reoriented by the insertion of a pipe into the grab ring.11. A ring according to any of the preceding claims wherein the sealing element is a resilient frustoconical sealing ring.12. A pipe coupling comprising a ring according to any of the preceding claims, the coupling comprising a mouth into which, in use, a pipe is introduced axially.cr) 10 13. A pipe coupling according to claim 12 wherein the ring is arranged in the pipe coupling with a reconfigurable portion angled radially and axially inwardly with CD respect to the axis along which, in use, a pipe is introduced, such that when a pipe is introduced, the reconfigurable portion is reoriented to a greater axially inward configuration.14. A pipe coupling according to claim 12 or 13 wherein the sealing element is a resilient frustoconical sealing ring having a long axis along the length of the conical section and a short axis perpendicular to the length of the conical section in the relaxed position, prior to introduction of a pipe, and the inner diameter of the frustoconical sealing ring is located closer to the respective mouth of the coupling than the outer diameter of the frustoconical sealing ring.15. A pipe coupling according to claim 14 wherein insertion of a pipe into the ring causes the frustoconical sealing ring to be deformed such that the inner diameter of the ring is smaller and the outer diameter is larger, so as to form a seal with the outer diameter of the pipe and the inner diameter of the coupling.16 A method of coupling a pipe comprising introducing a pipe into a pipe coupling comprising a ring according to any of claims 1 to 11.17. A method of coupling a pipe comprising introducing a pipe to a pipe coupling according to any of claims 12 to 15.18. A method of coupling a pipe according to claim 16 or 17 wherein as the pipe is introduced into the coupling a reconfigurable portion ofthe ring is reoriented and the sealing element is deforms so as to form a seal between the pipe and the (r) 10 coupling.19. A method of forming a grab ring comprising an integral sealing element, the CD method comprising overmoulding a sealing element onto a grab ring.20. A method of forming a grab ring according to claim 19 comprising overmoulding with an elastomer, to form an elastomeric sealing element.I5 21. A method of forming a grab ring according to claim 19 or20 wherein the grab ring is a ring according to any of claims 1 to 11.22. A grab ring, a ring comprising a sealing element, a pipe coupling, a method of coupling a pipe, or a method of forming a grab ring substantially as described herein with reference to the accompanying drawings.