GB2249367A - Push fit pipe coupling - Google Patents

Abstract

A pipe fitting which includes a housing (12) with a socket (22), a sealing ring (28) and a gripper ring (24) located in the socket, and retaining means (32) engaged with an inner surface of the socket to retain the sealing ring and the gripper ring in the socket. <IMAGE>

Description

This invention relates to a pipe fitting.

The invention provides a pipe fitting which includes a housing with a socket, a sealing ring and a gripper ring located in the socket, and retaining means engaged with an inner surface of the socket to retain the sealing ring and the gripper ring in the socket.

The pipe fitting is adapted to receive one end of a pipe which passes through the retaining means, the sealing ring and the gripper ring.

A stop formation may be provided in the socket to locate the pipe end when it is inserted into the socket.

The gripper ring may be adapted to engage with an outer surface of the pipe. The gripper ring may include a plurality of inwardly extending formations, which may be biased or resilient and which are adapted to engage with an external surface of the pipe. The gripper ring may permit movement of the pipe end in one direction relatively to the socket but restrain movement of the pipe end in the opposing direction.

The sealing ring may comprise any suitable device and may for example comprise an Ring.

The retaining means may take on any suitable form. In one example of the invention the retaining means comprises a washer with external gripping formations which are adapted to engage with an inner surface of the socket. The inner surface of the socket may include a groove or any other locating formation or formations adapted to receive the gripping formations of the retaining means.

In a second form of the invention the retaining means comprises an expanding ring such as a circlip which is adapted to locate in a groove or similar formation provided in an internal surface of the socket.

In a third form of the invention the retaining means comprises a ring which is inserted into the socket and which includes external formations which are located in a groove formed in the socket. The ring or at least its formations may be made from a resiliently deformable material to enable the formations to pass along the socket and then extend into the groove.

The gripper ring may abut a locating surface in the housing.

Spacers may be provided between the sealing ring and the retaining means, and between the sealing ring and the gripper ring, respectively.

The pipe fitting of the invention may be made from any suitable material such as a moulded plastics material or thin walled copper tubing.

The invention is further described by way of examples with reference to the accompanying drawings in which: Figure 1 is a side view in section of a pipe fitting according to one form of the invention, Figures 2, 3 and 4 illustrate different aspects of components which can be used in the fitting of Figure 1, Figure 5 is a view similar to Figure 1 of a pipe fitting according to a different form of the invention, and Figure 6 shows a detail of portion of the fitting of Figure 5.

Figure 1 of the accompanying drawings illustrates a pipe fitting 10 according to one form of the invention which includes a housing 12 which is moulded from a suitable plastics material and which has a bore 14, shoulders 16 and 18 and a groove 20 in a socket 22 at the mouth of the housing. The groove may be formed in the moulding process or may be formed thereafter by means of any suitable machining or similar operation.

A gripper ring 24 within the socket 22 abuts the shoulder 18. Against the gripper ring is a washer or spacer 26, an Olring seal 28, a second washer or spacer 30, and a retaining device 32 which abuts the washer 30.

The gripper ring 24 is of the type shown in fragmented view in Figure 3 in that it includes an outer annulus 34 and a plurality of inwardly extending and angled gripping formations 36. These formations are aligned, in the pipe fitting, in such a way that an end of a pipe 38 can be inserted into the socket 22, as is indicated by means of an arrow 40, but when an attempt is made to withdraw the pipe from the socket the formations 36 dig into the external surface of the pipe and engage tightly with it. A corner 38 of the shoulder 18 may be angled to provide open space for the formations 36.

The arrangement of the shoulder and the gripper ring, and the form of construction of the gripper ring, are given merely by way of example.

The retaining device 32 is shown in fragmented view in Figure 2 and includes an inner annulus 40 with a plurality of outwardly extending gripping formations 42 which are angled relatively to the annulus 40 when viewed from the side as shown in Figure 1.

The retaining device 32 although similar in many respects to the gripper ring 24 differs therefrom in that the gripping formations of the device 32 are on the outer surface of an annulus while in the other case the gripping formations are on an inner surface of the annulus.

The retaining device 32 can thus be pushed into the mouth of the socket 22 until such time as the gripping formations 42 enter the groove 20.

When this happens the components of the pipe fitting are secured inside the socket. It is to be noted that when use is made of the retaining device 32 shown in Figure 2 the provision of the groove 20 is not essential for the formations 42 automatically dig into the inner surface of the socket 22 and engage therewith in a manner which prevents retraction of the retaining device.

An advantage of the pipe fitting, and its method of assembly, is that the manufacture thereof is relatively simple and inexpensive. The sealing ring 28 provides a seal between the pipe and the housing and the gripper ring 24 secures the pipe to the housing. When the pipe and the housing are internally pressurized, during use, there is a tendency for the pipe to move outwardly relatively to the housing. The gripper ring is thereby moved axially towards the retaining device and in this way a further compressive force is applied to the O-ring seal 28 to enhance the sealing effect.

Instead of the gripper ring 32 shown in Figure 2 a circlip 44, shown in Figure 4, can be used. This circlip can be engaged directly with the groove 20 and can be made so that it can be contracted and withdrawn from the groove. This permits the pipe to be detached from the housing.

Figures 5 and 6 show a pipe fitting 60 according to a variation of the invention. In these Figures reference numerals which are similar to those employed in Figure 1 are used to designate similar components in the pipe fitting 10. The washer 30 and the retaining device 32 are dispensed with and are replaced by a collar 62 which fits around the pipe 38 and which includes a ring 64 which extends into the socket 22 and an optional flange 66 which extends from the ring 64.

On its outer surface, as is shown in enlarged detail in Figure 6, the ring 64 has a number of triangular shaped formations 68, or a single rib 68, which is shaped so that the ring can be inserted into the socket with an inclined edge of the rib being angled to the direction of movement. Once the rib reaches the groove 20 in the socket 22 it expands and locates the ring securely inside the socket.

The fitting of the invention can be made as a connector for interconnecting two pipes which are axially aligned, or as an elbow or bend, a T-piece, a crossover piece, or the like. In each case the housing 12 may be made with a number of ports which corresponds to the number of pipes which are to be interconnected by means of the pipe fitting. Each of the ports may be constructed in the way which has been described hereinbefore.

The aforementioned embodiments of the pipe fitting of the invention lend themselves particularly to being fabricated from a suitable plastics material by means of a moulding process. The gripper ring and retaining device are preferably made from a hard rust-resistant material such as stainless steel. The circlip 44 may be made from a similar material. It is apparent though that, particularly with the Figure 1 embodiment, the housing 12 could be metallic, and could be formed from suitably-shaped thin-walled copper or similar tubing. The retaining device 32, when pushed into the socket 22, can then be engaged directly with an inner surface of the socket, which is relatively soft.

The principles of the invention can be embodied in a variety of fittings which exhibit different characteristics and for this reason the scope of the invention is not confined to the particular embodiments shown in the accompanying drawings nor described hereinbefore.

Claims (8)

1. A pipe fitting which includes a housing with a socket, a sealing ring and a gripper ring located in the socket, and retaining means engaged with an inner surface of the socket to retain the sealing ring and the gripper ring in the socket.

2. A pipe fitting according to claim 1 wherein the gripper ring includes a plurality of inwardly extending formations which are adapted to engage with an external surface of a pipe which is inserted into the socket.

3. A pipe fitting according to claim 1 or 2 wherein the sealing ring is an Ring.

4. A pipe fitting according to any one of claims 1 to 3 wherein the retaining means comprises a washer with external gripping formations which are adapted to engage with an inner surface of the socket.

5. A pipe fitting according to any one of claims 1 to 3 wherein the retaining means comprises an expanding ring which is adapted to locate in a groove or similar formation provided in an internal surface of the socket.

6. A pipe fitting according to any one of claims 1 to 3 wherein the retaining means comprises a ring which is inserted into the socket and which includes external formations which are located in a groove formed in the socket.

7. A pipe fitting according to any one of claims 1 to 6 which includes spacers between the sealing ring and the retaining means, and between the sealing ring and the gripper ring, respectively.

8. A pipe fitting substantially as hereinbefore described with reference to Figures 1, 2 and 3, or Figures 1, 3 and 4, or Figures 5 and 6, of the accompanying drawings.