This invention relates to connectors, and more particularly, but not exclusively, to a connector for connecting two or more items such as tubular members, for example, pipes, tubes, or rods or other fittings, in which a push-fit arrangement is utilised.

Despite a vast number of prior proposals, the connection of hollow tubular members, such as pipes or tubes, to each other, or to fittings such as valves, bends, reducers, or tees, is still a laborious business. Present day fittings for connecting pipes or tubes are relatively expensive and require considerable skill and effort to assemble them in a leak-proof manner, particularly if the pipe or tube is to carry a fluid under pressure. The fittings usually comprise a number of parts, many of which are quite small. These can easily be lost, or dropped, whereupon they can readily be contaminated with dirt and dust leading to inadequate sealing.

One form of known connector, for example, comprises an olive and a plurality of threaded parts which can be assembled together and which, on assembly, force the olive into sealing contact with the pipe. These

connectors are easily loosened by mechanical vibration or thermal cycling, and are prone to leakage.

It has been proposed in GB1520150 and in GB1556008, the entire disclosures of which are incorporated herein by reference, to provide a pipe coupling comprising a first socket portion for receiving a pipe-end as a close sliding fit and a second socket portion with a larger diameter, an end cap secured to the outside of the second socket portion and having a radially inwardly projecting portion with an internal diameter not less than the internal diameter of the first socket portion, a toggle ring housed in the second socket portion adjacent a shoulder between the first socket portion and the second socket portion, and a resilient sealing ring housed between the toggle ring and the inwardly projecting portion of the end cap, which has a skirt internally screw threaded and the outside of the second socket portion is provided with mating screw threads. Whilst this connector can provide a good, leak-tight, push-fit connection, it still consists of several small individual parts and requires careful assembly.

Furthermore, in connecting tubular metal conduits, for example, for carrying electrical wiring and cabling, a strong, but not necessarily fluid-tight, connection is required. Hitherto, connections for such electrical conduits have required the provision of metal screw

fittings which are either cast or injection moulded, and then machined. Such fittings are relatively costly to produce.

There remains, therefore, a need for a push-fit connector having fewer individual parts which is simple and economical to manufacture, and is quick and requires no special skills to assemble.

The present invention addresses the aforementioned considerations.

Other UK Patent Application Nos. 9502176.2,

9511416.1 and 9519811.5, in the name of the present Assignees, also describe demountable pipe connectors.

The entire disclosures of these applications are herein incorporated by reference for all purposes.

For the avoidance of doubt, by connector it is not meant that the connector is necessarily independent of the two or more items to be connected, rather, one or more of the items to be connected could comprise elements of the connector. For example, the tubular members could form part of a pipe or other fitting. In this way the pipe or fittings could comprise elements of the connector.

The present invention provides a push-fit connector for a tubular member wherein a gripping means for the pipe or tube is mounted on the body of the connector.

According to a first aspect of the present invention, there is provided a connector between a first tubular member and a second tubular member, wherein the first tubular member has an open end adapted to receive the second tubular member in axial sliding engagement therewith, and wherein there is further provided gripping means mounted on the wall of one of the said tubular members and adapted to bear upon the wall of the other tubular member in gripping engagement therewith.

The first and/or second tubular member may form part of other fittings such as valves, bends, reducers, tees, or other fittings or connectors such as those described in our copending International applications "Connectors" (Agents Ref: P31074PC), "Connectors" (Agents Ref: P31350PC), "Connectors" (Agents Ref: P31364PC), filed herewith the entire disclosures of which are incorporated herein by reference for all purposes.

In a preferred embodiment the connector is adapted so that the second tubular member is rotatable with respect to the other without, preferably, loss of sealing capability where provided. In this embodiment, the connector can be used with the pipe connector and

pivotable radiator described in copending International application entitled "Connectors" (Agents ref: P31350PC)

In a further embodiment there may be provided annular sealing means adapted to form a seal between the first tubular member and the second tubular member, the arrangement being such that the gripping means and the sealing means are axially spaced apart and the gripping means is positioned between the sealing means and the open end of the first tubular member.

Preferably the connector makes a push-fit connection with the second tubular member without requiring the screwing of a locking nut or the use of any other moving parts.

If the second tubular member to be connected has a smooth surface, it can be advantageous to provide the gripping means with sharpened points or leading edges to enable them to cut into the surface of the first tubular member to obtain a firm grip. Alternatively, the second tubular member can be provided with an annular groove or recess in which the gripping means are a snap fit. In the latter case the gripping means do not need to bear hard against the surface of the tubular member, because interference with the groove walls should provide adequate pull-out resistance. Thus the first and second

tubular members may be rotatable one with respect to another.

Alternatively or in addition, one of the said tubular members is provided with a plurality of radial extending gripping means located circumferentially thereof and the other of said tubular member may be provided with an annular groove or recess in which the gripping means are received in snap-fitting engagement when the second tubular member is received in the first tubular member.

The first tubular member is preferably adapted to receive the second tubular member as a close sliding fit within the open end, such that the first tubular member surrounds the inserted end of the second tubular member. The first and second tubular members are preferably made from metal, and for example, they can be made from brass, copper, or steel, and especially stainless steel.

The tubular members may be circular in cross- section, or they may be square, rectangular or polygonal as required. The tubular members can have any suitable diameter dependent upon the application, but in general, their diameters will be within the range of from about 8.0mm to 50.0mm. The wall thicknesses of the tubular members will also depend upon the application, but they

will usually lie within the range of from about 0.5mm to 3.0mm.

In one embodiment, the connector is adapted such that one tubular member can be rotated with respect to the other tubular member. Preferably the adaptation comprises the provision of an annular groove on one tubular member and cooperating resilient members on the other tubular member.

In a preferred connector according to the invention, the gripping means is provided on the first tubular member and extends radially inwards, and the annular groove or recess is provided on the outer surface of the second tubular member.

In a preferred connector according to the invention, the gripping means is integral with its associated tubular member, which is preferably the first tubular member as aforesaid. Preferably the gripping means comprises an annular ring of resilient gripping members, and, for example the gripping means can comprise one or more rings of gripping tangs, preferably formed from a resilient material. The tangs are preferably angled with respect to the longitudinal axis of the associated tubular member and are preferably arranged on the internal wall of the first tubular member such that they point generally in the direction of insertion of the

second tubular member. In this position they can be relatively easily resiliently deformed when inserting the second tubular members into the first tubular member, and exert little resistance to the insertion, but provide a substantial resistance against axial-directed pull out forces when located in the groove or recess. Any suitable number of tangs may be provided, but usually between four and ten, for example about six, are sufficient.

Preferably the tangs, or other gripping members, are formed by making cuts or slots in the wall of the first or second tubular member and then pressing material of the wall of the tubular member either inwardly or outwardly as appropriate. The length and breadth of the tangs will depend on the application, but in general, the tangs are preferably from 1mm to 5mm in length, and preferably have a width of from 0.5mm to 3.5mm at their base. The tangs can, for example, be pointed or wedge- shaped, as desired.

The annular groove or recess can be provided in either the internal surface of the first tubular member or the external surface of the second tubular member, but preferably it is provided in the external surface of the second tubular member. The annular groove or recess preferably extends around the entire circumference of its associated tubular member. The depth of the annular

groove or recess should not be such as to weaken substantially the wall of its associated tubular member. In general, the annular groove or recess preferably has a depth of from 0.5mm to 2.Omm and a width of from 0.5mm to 2.0mm.

The first and second tubular members can be elongate, for example, pipes, tubes, or conduits, or one or more of the tubular members can be a fitting, for example, an in-line connector, a tee connector, a reducer, or a bend or may comprise part of a coupling or fitting such as those described in our copending International applications "Connectors" (Agents Ref: P31074PC), "Connectors" (Agents Ref: P31350PC), "Connectors" (Agents Ref: P31364PC). These combined couplings are intended to lie within the scope of this application.

The annular sealing means is preferably formed from a resilient material, and can comprise, for example, one or more '0*rings, which may be made from natural or synthetic rubber, or any suitable polymeric material. The 'O'ring may be of any material selected so as to suit a particular application or location, for example, it may compromise material resistant to chemical susceptibility or chemical attack. The O'ring or '0'rings are preferably located in an annular groove formed in the wall of the first tubular member of the connector.

The connector may have one open end, for example, when joining a pipe to a fitting, or may have two or more open ends, for example an in-line coupling, or a tee fitting. A stop member, which can, for example, be an annular shoulder on the first tubular member, may be provided to limit the extent of sliding engagement of the first tubular member of the connector with the second tubular member.

Preferred embodiments of connectors according to the invention will now be described with reference to the accompanying Drawings in which:

Figure 1 shows a first connector according to the invention in sectional side elevation;

Figure 2 shows the connector of Figure 1 in end elevation; and

Figure 3 shows an exploded perspective view of a second connector according to the invention; and

Figure 4 shows part of the assembled connector of Figure 3 in sectional side elevation.

Figure 5 shows an isometric view of a disassembled connection in accordance with a further aspect of the invention.

Referring to Figures 1 and 2, the first connector, illustrated generally at 1, comprises a body member 2 having an open end 3. Within the open end, and adjacent to the lip thereof, there is positioned a plastic washer 4, which acts as a bearing for locating and guiding the pipe into the body member. Arranged around the body member are a series of teeth 5 which depend inwardly, and which have been pressed out of slots 6 cut in the wall of the body member 2. An O'ring sealing member 7 is located in an annular groove 8 formed in the wall of the body member 2. A shoulder 9, acting as a stop member, is provided in the internal surface of the body member 2. The connector has a profiled outer surface 10, to receive a second connecting part as described in our co- pending UK patent application no. GB9502176.2 entitled "Improvements in or relating to Demountable Connections" and filed on 3 February 1995 and our copending International application "Connectors" (Agents Ref: P31074PC) filed herewith.

In operation, a tubular member such as a pipe is simply pushed axially into the open end of the body member 2, displacing the teeth slightly outwards, and progressing until it meets the shoulder stop member 9. The pipe or tubular member is now sealed by the 'O'ring and prevented by the ring of resilient teeth 6 from axial pull out.

The connector of Figures 1 and 2 can be quickly fitted in a simple push-fit operation and requires no special tools or consumables. It is inexpensive to manufacture, can be of substantially unitary construction, and can be used to join metal and plastic pipes and fittings without any special adaptation.

Referring now to Figures 3 and 4, the second connector embodiment, illustrated generally at 20, comprises a body member 21 having an open end 22. Within the open end 22, and adjacent to the lip thereof, there is positioned a plastics washer 23, which acts as a bearing for locating and guiding the pipe into the body member. Arranged around the body member are a series of inwardly depending resilient wedge-shaped teeth 24, which have been pressed out of slots 25 cut in the wall of the body member 21. An O'ring sealing member 26 is located in an annular groove 27 formed by deforming the wall of the body member 21 outwardly. A shoulder 28, acting as a stop member, is provided in the internal surface of the body member 21.

The pipe 29 to be connected, is a sliding fit within the plastics washer 23 and the body member 21, and is provided with an annular groove or recess 30 in its outer surface. The groove 30 can be easily machined or cut with conventional equipment. The distance of the groove from the end 31 of the pipe is arranged such that when

the pipe is inserted in the connector 20, and the end 31 of the pipe abuts against the shoulder 28, the teeth 24 re a snap fit in the groove 30.

To make the connection, the pipe 29 is pushed axially into the open end 22 of the connector, displacing the resilient teeth 24 outwards, until the end 31 abuts against the shoulder 28. As the pipe is pushed home, a click will be heard as the teeth snap back into the groove 30 indicating that the connection is completed.

The presence of the groove 30, as well as providing an audible indicator of the connection, thereby facilitating assembly, also increases the strength of the connection. A further advantage of this embodiment is that, because the teeth do not need to cut into the surface of the pipe, the pipe can be rotated in the connector, even when the connector is under pressure.

Referring to Figure 5, the connection, indicated generally at 41, comprises a hollow tubular member 42 having a circumferentially arranged ring of tangs 43 which depend radially inwardly, and which have been pressed out of slots 44 cut in the wall of the first tubular member 42. The tangs 43 depend inwardly at an angle to the axis of the first tubular member and point generally in the direction of insertion of the second tubular member 45.

The second tubular member 45 has an external diameter such that it is a close fit within the first tubular member 42 and has an annular groove 46 in its outer wall 47.

In use, when the second tubular member 45 is inserted axially within the first tubular member 42 the angled tangs 43 are displaced outwards, permitting the second tubular member 45 to slide into the first tubular member 42. Once the groove 46 has passed the ring of tangs 43 the second tubular member 45 can be pulled back so that the tangs 43 slide along the wall 47 and snap back and lock into the groove 46.

The first and second tubular members are now firmly locked together and the second tubular member cannot be withdrawn.

It will be appreciated by those skilled in the art that the connector of the invention may be used as a plug, air vent or the like.

Alternative embodiments of the invention can be envisaged by those skilled in the art from the information contained herein. All such alternative embodiments are intended to lie within the scope of this application.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment. This invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any

novel one, or any novel combination, of the steps of any method or process so disclosed.