GB2148435A - Improvements in or relating to pipe couplings - Google Patents

Abstract

The invention provides a pipe coupling including a pipe-like member 1 adapted to encircle an end of pipe and a resilient annular ring 2 for fitting within the pipe-like members and constituting an internal pipe stop. The annular ring has a plurality of outwardly extending lugs 3. A plurality of grooves 4 is located within the pipe-like member and adapted to receive the corresponding lugs of the ring, whereby a force generally axial to the pipe-like member applied to the ring between two lugs when engaged in the grooves causes the ring to flex to free the lugs from the grooves and the ring from the pipe-like member. <IMAGE>

Description

SPECIFICATION Improvements in or relating to pipe couplings This invention relates to pipe couplings, and more particularly although not exclusively to pipe couplings of the kind comprising a hollow pipe-like member adapted to encircle an end of a pipe sealed with respect to the member, and/or locked into the member.

The pipe-like member may comprise a sleeve open at each end, adapted to receive the ends of two pipes so as to form a pipejoint therebetween.

Pipe couplings of this kind are commonly used in the connection of pipes of thermoplastics material, for example.

With pipe couplings of this kind it is common to ensure that the sleeve is provided with an internal stop in the form of one or more projections or projecting members extending radially inwardly within the pipe-like member, the stop acting to restrict the possible movement of a pipe end into the pipe-like member.

Such stops can be of use to ensure correct axial location of a pipe within the pipe-like member.

It is however at times desirable that the coupling does not have such an internal stop.

Thus, for example, it may be desired to insert a pipe beyond the normal distance within the pipe-like member. This can arise, for example when coupling pipes, such as gas pipes forming part of already laid pipework, where two pipe ends are in close end to end relationship.

In this case one pipe end may be lifted out of line with the other, a coupling sleeve without an internal stop is passed fully over that one pipe end, which is then brought back into line with the other pipe and the sleeve moved back so as to encircle both pipe ends. To accommodate this possibility, it has been proposed that the internal stop be provided by an inwardly extending annular member firmly but removably mounted within the sleeve. However such arrangements as have been proposed have required the use of a lever to remove them, when required, from the sleeve with consequent risk of damage by the lever to the internal surface of the sleeve.

It is an object of the present invention to overcome or at least substantially reduce the above mentioned problem.

According to the invention there is provided a pipe coupling including a pipe-like member adapted to encircle an end of a pipe; a resilient annular ring for fitting within the pipe-like members and constituting an internal pipe stop, the annular ring having a plurality of outwardly extending lugs; and a plurality of grooves located within the pipe-like member adapted to receive the corresponding lugs of the ring, whereby a force generally axial to the pipe-like member applied to the ring between two lugs when engaged in the grooves causes the ring to flex to free the lugs from the grooves and the ring from the pipe-like member.

The pipe-like member may comprise a sleeve open at each end adapted to receive the ends of two pipes in end to end relationship.

With the arrangement of the invention an internal pipe stop is provided by fitting the ring within the sleeve with the lugs engaged in the grooves. A pipe entered into the sleeve having an end face (as is normal practice) at right angles to the axis thereof, abuts against the ring with an even force therearound and is located positively thereby. However, should it be wished to remove the stop, a force exerted generally axially of the ring at a location between two lugs causes the ring to flex such that the lugs spring from their retaining grooves, the ring tilts within the sleeve, and can be pulled from the sleeve. Such removal can be carried out easily without the use of any lever or similar hard or sharp implement.

Three or four grooves may be located around the sleeve spaced equally apart, and the ring may be provided with a corresponding number of radially extending lugs.

In order that the invetion may be more readily understood, one embodiment thereof will now be described by way of example with reference to the accompanying drawing which is a schematic isometric view of a pipe cou pling according to the invention.

Referring to the drawings it will be seen that there is provided a sleeve 1 of polyethylene arranged in use to be fitted around polyethylene pipes (not shown) adapted to be inserted in the sleeve.

A resilient ring 2 of an acetal copolymer having three outwardly extended lugs 3 is arranged to be inserted into the sleeve such that the lugs engage in corresponding internal grooves 4 in the sleeve such that the ring then lies in a plane normal to the axis of the sleeve. The dimensions of the lugs and the grooves, in width, length, and depth, are such as to provide normal working tolerances for location one within the other.

When the ring 2 is located within the sleeve 1, a force applied evenly around the ring, such as would be applied by a pipe having an end face at right angles to its axis, would not remove the ring from the sleeve. We have found that the ring is so firmly located that its removal could only be achieved by a force exerted by the pipe such as to fracture the lugs on a direct shear basis. In addition the firm location within the sleeve is aided by arranging that the dimensions are such that the outer diameter of the ring is slightly larger than the inner diameter of the sleeve ensuring that in normal circumstances the ring fits tightly within the sleeve.

In contrast, a force exerted on the ring 2 when located within the sleeve 1 in the direction and at the location of the arrow 5, causes the ring to flex from its natural plane and the lugs 3 to spring from the grooves 4 so that the ring can be removed from the sleeve.

By means of the invention we have provided an internal stop readily removable but positive in action and secure in location when required.

Claims (7)

1. A pipe coupling including a pipe-like member adapted to encircle an end of a pipe; a resilient annular ring for fitting within the pipe-like members and constituting an internal pipe stop, the annular ring having a plurality of outwardly extending lugs; and a plurality of grooves located within the pipe-like member adapted to receive the corresponding lugs of the ring, whereby a force generally axial to the pipe-like member applied to the ring between two lugs when engaged in the grooves causes the ring to flex to free the lugs from the grooves and the ring from the pipe-like member.

2. A pipe-like coupling according to Claim 1 wherein the pipe-like member comprises a sleeve open at each end adapted to receive the ends of two pipes in end to end relationship.

3. A pipe coupling according to Claim 1 or 2 wherein three or four grooves are located internally around the sleeve spaced equally apart, and the ring is provided with a corresponding number of radially outwardly extending lugs for engagement therewith in.

4. A pipe coupling according to any one of the preceding claims wherein the sleeve is formed of polyethylene, and the annular ring is formed of an acetal copolymer.

5. A pipe coupling according to any one of the preceding claims wherein the annular ring is radially unbroken.

6. A pipe coupling according to any one of claims 1 to 4 wherein the annular ring is in the form of a split ring.

7. A pipe coupling substantially as shown in and as hereinbefore described with reference to the accompanying drawing.