GB2278656A - Pipe couplings - Google Patents

Abstract

A pipe coupling comprises a socket the wall of which defines a mouth (4) for receiving a pipe end (1). An annular ring (11) is rotatably mounted on the socket mouth to define with the socket mouth an enclosed annular space when a pipe end is inserted in said mouth, and wherein an aperture (17) is provided in said annular ring which opens into said enclosed space through which adhesive can be applied under pressure. The ring (11) may comprise an end cap (14) having a cylindrical wall to extend into and snap fit within a counterbore (5) in the socket mouth, the end cap having an opening providing a tight fit on the pipe end. Alternatively, said annular ring may comprise an end cap having a cylindrical wall adapted to extend over and be a snap fit on the external wall of the socket mouth. <IMAGE>

Description

PIPE COUPLINGS This invention relates to pipe couplings more particularly - but not exclusively - for connecting together plastics pipe lengths, said coupling being of the type comprising a socket having a mouth for location of an inserted pipe, said socket and pipe being secured together and sealed via an adhesive which, in the case of plastics, is preferably a mastic or a solvent.

The assembly of such couplings is normally time consuming and cumbersome, involving applying the adhesive manually by smearing it over the pipe end and into the socket before insertion of the components.

Furthermore, in the case of plastics pipes, the mastic or solvent products used can be a health hazard if breathed continually and it is recommended that a mask be used when working with such products.

In our co-pending U.K. Patent Application No.

92082601.1 Serial No. , a pipe coupling of the type discussed above is proposed in which manual application of the adhesive is avoided by use of an encapsulated ring of adhesive which is located within the socket mouth and is ruptured during insertion of a pipe end into the socket mouth to release the adhesive onto and around said pipe end.

In our co-pending U.K. Patent Application No.

9217510.8, Serial No. , an alternative arrangement for avoiding manual application of the adhesive is achieved by the provision of an annular recess provided in the inner peripheral surface of the socket mouth and at least one aperture extending through the socket wall and opening into said recess, the socket mouth being dimensioned to slidably receive a pipe end and the arrangement being such that, after insertion of the pipe end, adhesive can be introduced under pressure via said aperture into said annular recess for sealing around the pipe end. In a preferred coupling arrangement described in this Application, the annular recess is formed as a counterbore extending into the socket mouth with an annular ring located in its open end, the assembly thereby defining a groove between said ring and the blind end of the counterbore, and the annular ring is formed with an inwardly directed feather edge of a dimension which is an interference fit on the pipe end, the arrangement being such that the feather edge is deformed onto the outer periphery of the pipe end during insertion of the latter so that, when adhesive is introduced into the groove, its pressure will tend to tighten said feather edge onto the pipe end to prevent leakage. This preferred coupling arrangment has been found to produce an effective seal, but some difficulties have been experienced in fitting the coupling on site.

The object of the present invention is to provide another alternative coupling arrangement, in which fitting on site is facilitated.

According to the present invention, there is provided a pipe coupling comprising a socket the wall of which defines a mouth for receiving a pipe end, wherein an annular ring is rotatably mounted on the socket mouth to define with the socket mouth an enclosed annular space when a pipe end is inserted in said mouth, and wherein an aperture is provided in said annular ring which opens into said enclosed space through which adhesive can be applied under pressure, the arrangement being such that, prior to application of the adhesive, the ring can be rotated to bring the aperture into a readily accessible position.

In one preferred form, said annular ring comprises an end cap having a cylindrical wall adapted to extend into and be a snap fit within a counterbore provided in the socket mouth, the end cap having an opening dimensioned to provide a tight fit for a pipe end inserted into the socket mouth and the inner dimension of the cylindrical wall being larger than the outer diameter of the pipe end to be fitted so as to define at least a part of said enclosed annular space.

In this form, particularly where the components are made of resilient plastics material, snap fitting may be effected by a co-operating tongue and groove arrangement in the cylindrical wall and counterbore, in which case it will be appreciated that when adhesive is applied, the pressure created will act to tighten said co-operating tongue and groove to prevent leakage.

In another preferred form, said annular ring comprises an end cap having an end wall defining an opening dimensioned to provide a tight fit for a pipe end inserted into the socket mouth and a cylindrical wall adapted to extend over and be a snap fit on the external wall of the socket mouth. In this form, the enclosed annular space need not be defined by a counterbore in the socket mouth. Instead, the space may be defined between the free edge of the socket mouth and the end wall of the end cap.

With either form of coupling arrangement described above, leakage of adhesive through the end cap opening can be avoided by providing said opening with an inwardly directed feather edge similar to that described in co-pending U.K. Patent Application No. 9217510, Serial No. whereby, under the pressure of adhesive applied via said aperture, the feather edge is tightened onto the pipe end.

In order that the invention may be readily understood, a preferred embodiment of pipe coupling for a plastice drain pipe in accordance therewith will now be described, with reference to the accompanying drawings, in which: Figure 1 is a cross-section of the preferred coupling arrangement of co-pending U.K. Patent Application No. 9217510.8 Serial No.

discussed above, Figure 1A is an enlarged detail of Figure 1, Figure 2 is a cross-section of one preferred coupling arrangement according to the present invention, Figure 2A is an enlarged detail of Figure 2, Figure 3 is a cross-section of another preferred coupling arrangement according to the present invention, and Figure 3A is an enlarged detail of Figure 3 Referring to Figure 1, this shows the parts 1, 2 of its coupling arrangement separated on the left hand side and connected on the right hand side of the centre line. In this arrangement an annular recess in the form of a groove 3 is provided within the socket mouth 4. The groove is defined by providing a counterbore 5 which extends into the socket mouth and locating an annular ring 6 in the open end of the counterbore. The ring 6 is of resilient plastics material and, as shown in Figure lA, has an outwardly projecting tongue 7 which is a snap-fit into a mating locating groove formed in the inner peripheral surface of the mouth opening. One or more apertures 8 open into this defined groove through which an adhesive can be applied under pressure.

The annular ring 6 is formed with an inclined internal projecting feather edge 9 which is dimensioned to be an interference fit on a pipe end constituting the coupling part 1. Thus, during insertion, the feather edge is deformed around the outer surface of the pipe end to be a tight fit thereon. Furthermore, when adhesive 10 is introduced into the groove, its pressure tends to tighten the feather edge further onto the pipe end to virtually eliminate the possibility of leakage occuring.

Referring now to Figures 2 and 2A, in one preferred arrangement of the present invention, the open end of the socket mouth 4 is also provided with a counterbore 5 which, however, is intended to rotatably support an annular ring 11. Thus, the cylindrical wall 12 of the ring (see Figure 2A) is dimensioned to be a sliding fit within the socket mouth 4 and has a peripherally extending tongue 13 which cooperates with a locating groove 13A formed within the socket mouth. The ring is in the form of an end cap having an end wall 14 with a central opening 15 which is dimensioned to be a tight sliding fit for a pipe end 1 inserted therethrough into the socket mouth. The end wall is chamfered as shown at 16, and a single opening 17 is provided through the end wall, which is nozzle-shaped in this embodiment.

It will be npted from Figure 2, that when the pipe end 1 is located within the socket mouth an annular enclosed space is defined bounded by the inner face of the cylindrical wall 12 of the end cap 11 and the blind end of the counterbore 5 into which adhesive is applied under pressure, via the nozzle opening 17, from a suitable applicator. It will be appreciated that the pressure of the adhesive will force the ring 11 to seat tightly within the socket mouth and its tongue 13 will prevent external leakage of the adhesive. After curing, the ring 11 will be held rotatably fast within the socket mouth.

In another preferred arrangement, as shown in Figures 3 and 3A the end cap 11 is in the form of a collar which is rotatably mounted on the outer surface of the wall of the socket mouth by providing a peripherally extending tongue 13, which in this embodiment is formed on the wall of the socket mouth, and a mating groove 13A formed in the inner surface of the collar, the parts being dimensioned and shaped so that they may be snap-fitted together due to the resilience of the plastics material from which they are preferably made. In this embodiment, the collar is extended beyond the open end of the socket mouth and the end wall 18 of the end cap is provided with an inwardly directed feather edge 19 substantially as described in said copending U.K. Patent Application No. 9217510.8, Serial No. . This provides an advantage, compared with the previously described embodiment, that a counterbore is not required for the socket mouth; instead, when the pipe end 1 is located in the socket mouth, the feather edge 19 provides an interference fit on said pipe end and defines, with the extended part of the collar and the free edge of the socket mouth, an enclosed annular space for receiving adhesive under pressure through a nozzle opening 17 extending through the wall of the collar. It will be appreciated that such a feather edge could be provided for the opening 17 of the end cap 11 of the previously described embodiment, if leakage of adhesive proves to be a problem.

As discussed hereinbefore, a problem with the preferred arrangement described in our co-pending U.K.

Application 9217510.8, Serial No. is that, during fitting on site, difficulties of access to the . adhesive filling opening can occur. These difficulties are simply overcome with an arrangement in accordance with the invention by appropriately rotating the ring end cap 11 to a readily accessible position prior to application of the adhesive.

Claims (7)

1. A pipe coupling comprising a socket the wall of which defines a mouth for receiving a pipe end, wherein an annular ring is rotatably mounted on the socket mouth to define with the socket mouth an enclosed annular space when a pipe end is inserted in said mouth, and wherein an aperture is provided in said annular ring which opens into said enclosed space through which adhesive can be applied under pressure, the arrangement being such that, prior to application of the adhesive, the ring can be rotated to bring the aperture into a readily accessable position.

2. A coupling according to Claim 1, wherein said annular ring comprises an end cap having a cylindrical wall adapted to extend into and be a snap fit within a counterbore provided in the socket mouth, the end cap having an opening dimensioned to provide a tight fit for a pipe end inserted into the socket mouth, and the inner dimension of the cylindrical wall being larger than the outer diameter of the pipe end to be fitted so as to define at least a part of said enclosed annular space.

3. A coupling according to claim 2, wherein a co-operating tongue and groove arrangement is provided in co-operating surfaces of the cylindrical wall and counterbore to effect snap fitting, said co-operating tongue and groove also acting to prevent leakage of adhesive applied under pressure.

4. A coupling according to Claim 1, wherein said annular ring comprises an end cap having an end wall defining an opening dimensioned to provide a tight fit for a pipe end inserted into the socket mouth and a cylindrical wall adapted to extend over and be a snap fit on the external wall of the socket mouth.

5. A coupling according to Claim 4, wherein said enclosed annular space is defined between the free edge of the socket mouth and said end wall.

6. A coupling according to Claim 2, 3, 4 or 5, wherein said opening in said end wall has an inwardly directed feather edge which is an interference on the pipe end and which acts under the pressure of adhesive applied via said aperture to tighten onto the pipe end to prevent leakage.

7. A pipe coupling constructed, arranged and adapted for use substantially as hereinbefore described with reference to Figures 2, 2A, or 3, 3A of the accompanying drawings.