The invention relates to connectors, particularly to connectors such as seals and couplings used where two pipes are to be joined together, in line usually, for providing fluid flow between and through the two pipes.

In such situations, it is usually provided that there are seals which are effective to prevent leakage. However, under stress, such seals have a tendency to deteriorate. At the same time, they are usually complicated and therefore expensive to manufacture and assemble. Moreover, the two pipes are often provided ready assembled so that the pipes to be coupled can be installed with a direct push-in action. The coupling is then required to maintain the pipes in the required installed state in the coupling without disruption, that is the physical integrity of the coupling has to be maintained so that flow is achieved without leakage. To this end, collets have been provided which grip the metal pipe of the assembly, but these collets suffer from the disadvantage that they are prone to failure because elements intended to grip the pipe are liable to lose any inherent grip they had and to allow the pipe to become loose, leading to failure of the coupling.

It is accordingly an object of the invention to seek to mitigate these disadvantages.

According to a first aspect of the invention there is provided a connector for use in a pipe coupling system, comprising a body characterised by at least two integral pans (2, 3, 40, 50) which define a toroidal seating in an inner pipe of the pipe coupling system, whereby on appliance of axial pressure the pans (2, 3, 40, 50) move relatively to reduce the diameter of the seating (4, 30).

At least part of the body may be attenuated under pressure. This provides for a positive connection.

The whole of the connector may be attenuated under pressure. This provides for a positive connector and an effective operation in use.

There may be two spaced external annuli and an internal pipe engaging surface, and the connector or seal may be attenuated radially under axial pressure.

This provides for a radial squeezing component of force on a pipe in use. The pipe-engaging surface may be a V-shape in cross-section whereby to provide an apex adapted to bear on a pipe. This provides for positive pipe engagement in use.

The connector or seal may have opposed surfaces at substantially 90° to the longitudinal axis of the body, adapted for butting against opposed coupling surfaces. This construction again provides for positive sealing action.

In an alternative, the connector or seal may comprise a body with a through cylindrical bore of constant internal diameter. This provides for a positive sealing action too.

The body may have a part which is cylindrical and a part which is frusto- conical. This assists in attenuation.

The frusto-conical part may be at one end of the seal. This is a relatively simple construction which assists in the attenuation action during sealing.

The angle of the frusto-conical part may be about 30° to the longitudinal axis of

the body, again, assisting during attenuation.

The body may have a surface at substantially 90° to the longitudinal axis thereof, adapted for butting against a surface of the coupling. This provides for a positive sealing action, particularly where the connector is moulded in one piece, suitably of a silicone rubber material or composite.

The connector may comprise a frusto-conical body having discrete segments adjacent ones of which are connected by resilient connector means.

The resilient connector means may each comprise a connector extending from or from near one axial end of one segment to or to near an axially opposite end of the adjacent segment. This provides for an integral construction.

The connector may extend to the axially opposite end of the adjacent segment. This provides for a relatively simple construction.

The segments may each bear on an interior surface in use, pipe gripping means. This assists in facilitating clamping of a pipe, particularly where the pipe gripping means comprises a plurality of teeth.

There may be at least one segment which may have means for mounting an additional pipe-engaging member. This enhances clamping of a pipe in use.

The additional means may comprise a bore through the body of a segment for mounting a stud means projecting towards the axis of the collet. This provides a positive clamping action.

The angle of the axis of the bore with the outer conical surface of the collet may

be substantially 90°. This enhances the clamping action, particularly when there is a stud means in the bore.

The means may also comprise a seating on an end of the segment adapted for seating a tooth projecting towards the axis of the body. This is an alternative yet effective additional gripping means for a pipe.

There may be a tooth in the seating.

The means may comprise a bore through the body of the segment for mounting a stud means projecting towards the axis of the collet and a seating on an end of the segment adapted for seating a tooth projecting towards the axis of the body. This provides a combination of a tooth and stud for enhancing gripping of a pipe; in use, the connector may include a stud in the bore and/or a tooth in the seating.

The angle of the axis of the bore with the outer surface of the body may be substantially 90°.

The stud means or tooth may comprise metal. This provides for a positive clamping engagement in the surface of a pipe.

Each segment may have a bore and or seating, and the cone angle of the connector may be about 20°.

The connector may be integrally made from a plastic material, suitably an acetal.

According to a second aspect of the invention there is provided a pipe coupling system, including a connector as hereinbefore defined.

Connectors and pipe coupling systems embodying same, are hereinafter described, by way of example, with reference to the accompanying drawings.

FigJ is a cross-sectional view of a first embodiment of connector or seal, according to the invention;

FigJ A shows schematically to a smaller scale the attenuation action on application of axial pressure to the seal of Fig.1 ;

Fig.2 is a cross-sectional view of a second embodiment of seal according to the invention;

Fig.2 A shows schematically to a smaller scale attenuation action on application of axial pressure to the seal of Fig.2;

Figs.3 and 3 A show side elevational views of a pipe coupling incorporating a seal according to Figs. 1 and IA, respectively in the as supplied and in use condition; and

Figs.4 and 4A show side elevational views of a pipe coupling incorporating a seal according to Figs. 2 and 2A, respectively in the as supplied and in use condition.

Figs. 5A, 5B and 5C show respectively plan, transverse sectional and side elevational views of another embodiment of connector according to the invention;

Fig. 5B being a section on the line 'A A' of Fig. 5A;

Figs. 6A, 6B and 6C show respectively plan, transverse sectional and side elevational views of a yet further embodiment of connector according to the invention, Fig. 6B being a section on the line 'A A' of Fig. 6A;

Figs. 7 and 7 A show side elevational views of a pipe coupling incorporating a connector according to Figs. 5 A to 5C respectively in the as supplied and in use condition;

Figs. 8 and 8 A show side elevational views of a pipe coupling incorporating a connector according to Figs. 6 A to 6C, respectively in the as supplied and in use condition; and

Figs. 9 and 10 show longitudinal sectional views of a pipe coupling system according to the invention in respectively a first mode and a second or gripping and sealing mode.

Referring to the drawings, in which like parts are indicated by like numerals, there is shown a connector for use in a pipe coupling system, comprising a body characterised by at least two integral parts (2, 3, 40, 50) which define a toroidal seating in an inner pipe of the pipe coupling system, whereby on appliance of axial pressure the parts (2, 3, 40, 50) move relatively to reduce the diameter of the seating (4, 30).

The connector or seal 1 is generally wholly attenuable readily under pressure, and comprises two spaced external annuli 2 and an internal pipe engaging surface 4. The annuli 2 are separated by a V-shape the apex 5 of which is directed towards the longitudinal axis 6 of the seal 1 , and lies on the centre line thereof on which line also has an apex 7 of a shallow 'V defining the internal pipe engaging surface 4. The seal 1 also has opposite surfaces 8 and 9 at right

angles to the longitudinal axis 6 of the seal 1 , which opposite surfaces 8, 9 butt against opposed surfaces in use in the pipe coupling 10.

In the assembled coupling 10, prior to insertion of pipes 11 and 12 respectively a 19.5mm lead pipe and a 25mm plastic pipe in the embodiment, the seal 1 has the configuration shown in Figs. 1 and 3. On application of axial pressure, the seal is attenuated i.e. lengthened, radially in the direction of arrow X, FigJA, the pipe engaging surface 4 being extended to flatten out and be pressed firmly against the pipe 11 , this being the result of axial pressure which forces the annuli 2,3 together in the direction of arrows Y, FigJA, so closing up the 'V . This is clearly shown schematically in FigJA and in Figs. 3 and 3A, where the pipe coupling has, as viewed in the direction from left to right, a clamp body 12 screw-threadedly engaged on a seal body 14 with an integral push fit 15. The seal 1 lies between opposed surfaces 16, 17 of a locking ring 18 and seal body 14 so that when the clamp body 13 is screwed into the locking ring 18, to the Fig.3A position, after insertion of the respective pipes 11 and 12 the locking ring 18 is urged to the right as viewed so that the seal 1 is compressed between the faces 16 and 17. The only way this can be accommodated is by closing up the 'V 5 and attenuating the surface 4 radially. Thus attenuation is effectively prevented by the surface of the pipe 11 , so the surface 4 is flattened out about apex 7 on contact with the pipe 11 so that a very firm seal is achieved.

There is a grip ring 19 and 'O' ring 20 in the push fit 15.

Referring now to Figs.2 and 2A, the seal 100 shown there has a cylindrical bore 101 of constant diameter and an external cylindrical part 102 and a tapered frusto-conical part 103 which in use is to the right (as viewed in Figs. 4, 4A) of the end of the pipe 11. The angle of the frusto-conical part 103 is about 30°. The seal 100 also has a surface 104 at right angles to the longitudinal axis 6 of

the seal 100 which in use butts against a surface 105 of the pipe coupling 10.

In an assembled seal 10 prior to insertion of a pipe 11 or 12, (Fig.4), the seal 100 is in the configuration shown in Fig.2, as clearly shown in Fig.4. When axial pressure is applied, the seal 100 is attenuated in the direction of the taper of the frusto-conical part 103 so that it firmly and securely extends over internal surfaces of the pipe coupling 10, the conical part 103 being attenuated and extending along an inserted nose of the pipe 11. Thus a secure seal is formed.

In Figs.4 and 4A, the pipe coupling 10 is similar to that described and shown in Figs. 3 and 3A, except that the seal body 14 and push fit 15 are separate. In Figs. 4 and 4A too, the locking ring 18 is cylindrical, the right hand end of which as viewed bears the surface 105 in order to apply axial pressure to the seal 100 and to attenuate it by extruding it along a frusto-conical part 21 of the seal body 14 between which surface and the pipe 11 the seal is firmly clamped to provide a positive seal.

The seals 1 and 100 may be made of silicone, and have the advantage that they can be used with a number of differing pipe sizes as considered on their external dimensions. The seal 1 may be used with a connector in the form of a collet 300 and the seal 100 be used with a connector in the form of a collet 200, see Figs. 3, 3 A and 4, 4 A respectively.

Referring now to Figs. 5 A to 5C of the drawings, there is shown the collet 300 for use in a pipe coupling system 302, comprising a frusto-conical body 303 having discrete segments 304 adjacent ones of which are connected by resilient connector means 305.

The collet 300 is for clamping or gripping an iron or lead pipe 301 in the pipe

coupling 302, and is integrally formed from a plastic such as an acetyl or nylon, the cone angle of the body 303 being 20°. The connector means 305 between adjacent segments comprises a relatively rigid yet resilient strap or strip 307 of material which extends in a curve from, or from near (as in the embodiment) the end of the body 303 of greater diameter, to a substantially straight part 308 which is spaced equidistantly from and is substantially parallel to the two adjacent segments 304 to an oppositely curved part 309 which is integral with the narrow end of the adjacent segment 304. Each segment 304 is thus joined with the next adjacent one circumferentially of the body 303. Thus each segment 304 has a degree of resilience or "give" with respect to its neighbour, so that the segments 304 can be pushed circumferentially ^* to wards one another by flexing of the connectors 305, which therefore act like springs.

Each segment 304 has on an interior surface means in the form of a plurality of teeth 310 for in use gripping the outer surface of the pipe 301. The collet 300 additionally has pipe gripping means in the form of a seating 311 on the end of each segment 304 at the end of the collet of widest diameter. The seating 311 is an L-shaped recess, or alternatively a slot in the end of the segment 304. In the seating or slot is mounted a metal tooth 312 also of 'L' -shape which has a pointed end protruding beyond the segment towards the longitudinal axis of the body 303 of the collet 301 so that in use the tip of the tooth 312 can bite into the pipe 301 (Fig.7A). The angle of the base of the L-shaped seating 311 extends at substantially 90° to the outer conical surface of the body 303.

The tooth 312 may be secured in the seating by any suitable means, such as glue.

Referring now to Figs. 6 A to 6C, the embodiment of collet 200 shown is similar to that of Figs. 5A to 5C, the difference being that additional pipe gripping

means comprises a bore 210 through each segment 304. The bores are countersunk and the longitudinal axis thereof is inclined at about 90° to the surface of the outer surface of the body 200. A stud means or screw 222 is inserted in the bore and is maintained therein by any suitable means such as by an interference fit or glue, the tip of the stud 222 being pointed and projecting to the interior of the collet 200 to engage in the outer surface of the pipe 301 , Fig. 8A.

Referring now to Figs. 7 and 7A, use of the collet 200 is shown in the pipe coupling system, which is assembled, reading from left to right in the Figures, of a clamp body 10' with a frusto-conical part 10"' in which the collet 200 is mounted. There is a locking-ring 10" within the clamp body 10' having a first part 203 of an inside diameter sufficient to receive the outside diameter of the pipe 301. The clamp body 10' is rotatably received in a seal body 204 which has an integral push-fit section 205 for receiving a plastic pipe 206, there being in the push fit section 205 a gripping ring 207 and an 'O' ring 208.

In use, when the pipe 301 , say a 19.5mm o.d. lead pipe is pushed into the coupling 200 from left to right, the teeth 310 and the additional teeth 312 bite into the outer surface of the pipe 301 the teeth 310, 312 all being angled to resist movement in the uncoupling direction (right to left). Thus once the pipe 301 is inserted to the full extent shown in Fig. 7A, it is not likely readily to be uncoupled, whatever pressures are exerted on the coupling and hence on the seal. The connectors 305 if they are stretched or tensioned try to resume their initial condition, so that the teeth 310, 312 always bite into the metal of the pipe.

Similar considerations apply to Figs. 8 and 8A, where the stud 222 and teeth 310 bite into the external surface of the pipe 310. In Figs. 8 and 8 A, there is a separate seal body 109 and push fit element 110.

Also, in Figs. 8 and 8 A, there is a seal 1 in the seal body 109 which has a cylindrical part and a conical part, which seal becomes attenuated or extruded towards the right as viewed to form a positive seal on the made up coupling. In Figs. 7 and 7 A the seal comprises a body having two outer annuli and an inner annulus intermediate them, respectively to engage the walls of the coupling and the pipe, the seal again being compressed and extruded when the coupling is made up by tightening the clamp body on the seal body, the surfaces sliding over one another to force the collet to clamp the pipe as the segments 304 are compressed against each other at 90° to the cone angle, hence decreasing the bore through the body, as in Figs. 7 and 7 A. The seals 1 , 100 are suitably made of silicone material, rubber or the like.

It will be understood that modifications are possible. Thus the studs 312 could comprise stainless steel screws with a push fit in the bore.

Also, the connectors 305 may be of 'V shape.

Figs. 9 and 10 show a particular pipe coupling system utilising a connector or collet 200 and a connection or seal 1 , the system being shown relaxed or unstressed in Fig. 9 and in the tensioned or stressed mode in Fig. 10 where the segments 204 of the connector 200 are closed up to force the studs 222 into a pipe, and the seal is attenuated to form a firm grip on the interior surface of the pipe 301.

Among the advantages of the connectors described herein is the ability to accommodate a variety of pipe sizes.