GB2246405A

GB2246405A - A pipe coupling

Info

Publication number: GB2246405A
Application number: GB9016614A
Authority: GB
Inventors: Ronald Pardy
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1990-07-28
Filing date: 1990-07-28
Publication date: 1992-01-29
Anticipated expiration: 2010-07-28
Also published as: GB2246405B; GB9016614D0

Abstract

A pipe coupling which allows a "quick fit" connection has a main body pan 10 with a socket for receiving the pipe end and a space for receiving an O-ring or other seal 18 to make a fluid-tight seal. A retention device 22 allows the pipe to be inserted in one direction but prevents it from being removed in an opposite direction. Normally the retention device is retained on the main body part, but can be separated from the main body part when it is desired to disconnect the coupling. <IMAGE>

Description

A PIPE COUPLING This invention relates to a pipe coupling of the type where one pipe end is pushed into a socket and where the action of pushing the pipe end into the socket both forms a seal and retains the pipe end in the socket.

In many pipe couplings of this type (see for example GB-PS 1 520 742) the mechanism which retains the pipe end in the socket can be rendered inoperative so that the pipe can be withdrawn from the socket when the coupling is to be disconnected. Such mechanisms are however usually complex and expensive.

According to the present invention, there is provided a pipe coupling comprising a main body part for connection to a first pipe and having a socket for receiving an end of a second pipe, a seal ring for sealing between the main body part and the second pipe, a retention device at the mouth of the socket which will allow the second pipe to be pushed into the socket but will retain the second pipe against withdrawal, and securing means securing the retention device to the main body part, the securing means being removable from the main body part.

The retention device preferably comprises a first part which grips the second pipe and a second part which can be connected to the main body part. In one embodiment the first and second parts of the retention device are formed from a single metal component which is suitably shaped. In another embodiment the first part and the second part are formed by separate components which cooperate with each other.

The first part of the retention device preferably comprises a plate with a hole through which the end of the second pipe can pass, the periphery of the hole being defined by a plurality of inwardly directed teeth surrounding the hole. The teeth are arranged so that when they lie in the plane of the plate, the circle formed by tne inner tips of the teeth has a smaller diameter than the external diameter of the second pipe end, but when the teeth are bent out of the plane of the plate, then the tips of the teeth form a circle of larger diameter than the pipe end circumference.

Where the retention device is a metal plate, the hole and the teeth can be formed by suitably cutting away parts of the metal, and the second part of the retention device can be formed by bending over ends of the metal plate and forming apertures in the bent over ends so that these can clip onto ears formed on the main body part.

Alternatively, the first part of the retention device may be a sprag washer, and the second part can be a screw-threaded collar which can screw onto a complementary thread on the main body part and can retain the sprag washer.

The main body part may be moulded integrally with the first pipe or may have an arrangement at its opposite end by means of which a pipe can be attached to the main body part.

In order to prevent the second pipe end from being scratched as it is pushed in through the retention device, a friction ring can be incorporated in the coupling. The friction ring will be fitted so that it either acts against the retention device to lift the teeth during insertion action or against the retention device to push the teeth inwards on attempted withdrawal. In the first case the friction ring will be placed so that the second pipe end passes through the friction ring before passing through the retention device and the teeth of the retention device will normally interfere with the pipe end. In the second case, the retention device normally has a diameter slightly larger than that of the pipe end, and the pipe end encounters the friction washer after passing through the retention device.When withdrawal of the pipe is attempted, the friction washer will be pulled against the retention device to force this against the pipe wall.

In addition to the sealing ring, which is preferably an 0-ring, the socket may include a mouldedin interference bead to form a secondary seal between the second pipe and the main body part. In addition, where the retention device includes a screw threaded collar, a part of the collar may form a secondary seal with a corresponding part of the main body part.

The seal ring may be retained in the main body part on disassembly of the coupling by moulding a suitable retaining lip into a seat for the seal ring in the main body part.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross section through a first form of pipe coupling in accordance with the invention; Figure 2 is a plan view of a retention device from the coupling of Figure 1; Figure 3 is a side view of the retention device shown in Figure 2; Figure 4 shows the pipe end separated from the socket; Figures 5 & 6 show two alternative forms of coupling components in a ccordance with the invention for use with the socket as shown in Figure 1; Figure 7 is a side view of a motor vehicle fuel tank showing a coupling in accordance with the invention in a typical application; Figure 8 is a cross section through the coupling of Figure 7; Figure 9 shows a sprag washer for use in the embodiment of Figure 8;; Figures 10 & 11 are respectively details in the areas indicated by the circles A and B from Figure 8; Figure 12 shows a third embodiment of coupling in accordance with the invention; Figure 13 shows part of a fourth embodiment of coupling in accordance with the invention; Figure 14 shows a component for use with the embodiments of Figures 12 & 13; and Figure 15 is a cross section through part of the main body part, in an alternative embodiment.

Figure 1 shows a coupling with a main body part 10 which forms a socket 12 into which a plain pipe end 14 can be pushed. The socket also has an annular recess 16 and an O-ring 18 is fitted in this recess. When the pipe end 14 is pushed into the socket 12, a seal is formed by the O-ring between the main body part and the pipe so that a fluid tight seal is formed between the bore of the pipe and a fluid passage 20 in the main body part. The fluid passage 20 can be part of a fixed structure or can be connected to a further pipe by the same or a different type of coupling.

In order to prevent the pipe from being pulled out of the socket 12, a retention device 22 is provided.

This comprises a metal plate with a central aperture 24 surrounded by teeth 26 which are bent out of the plane of the metal, as can be seen in Figure 1. Because the teeth 26 are bent in this way, they will yield to allow the pipe 14 to be pushed into the socket. However if the inserted pipe is pulled in the direction outward of the socket, then the teeth 26 will bite into the pipe material and will prevent withdrawal.

In order to hold the retention device 22 onto the main body part 10, the body part has a pair of diametrically opposite ears 28 and side walls 30 of the retention device have apertures 32 which clip over the ears 28. Engagement between the ears 28 and the bottom edges of the apertures 32 prevents the retention device from being pulled off. However if it is desired to disconnect the coupling, then the side walls 30 of the retention device 22 can be lifted so they pass over the ears 28, and the pipe can then be separated from the main body part. When this happens the retention device 22 and the O-ring 18 remain on the pipe end 14.

Refitting of the pipe end in the main body part is a reverse of the above procedure.

Figure 5 shows a similar construction where the 0ring 18 is replaced by a square section seal 34.

In Figure 6, a spacer 36 is mounted on the pipe end 14, and a shoulder 38 is formed on the pipe end in a conventional manner. The fitting of the spacer 36 in this position will prevent any damage to the 0-ring which might be caused by the ring fretting against the retention device 22.

In an alternative version, which is particularly suitable for larger diameter lines (eg 13/15mm diameter fuel tank sensing hoses) the retention device is differently formed. Figure 7 shows the application of this different form, and Figures 8 & 9 more details.

In Figure 7, a motor vehicle fuel tank 40 contains fuel 42 and has a fuel inlet pipe 44. A fuel filler pipe is shown at 46 through which the tank can be filled. A sensing hose 48 connects the air space 50 at the top of the tank with the top of the inlet pipe 44, and a pipe coupling 52 in accordance with the invention is used to connect one end of the sensing hose 48 to a fitting on the top of the tank.

The main body part 54 of the coupling 52 is secured directly in an aperture in the top of the tank.

Where both the tank wall and the body part 54 are of plastics, the two can be welded together. The body part 54 has a socket 56 into which an end of the sensing hose 48 is inserted, and an 0-ring 58 forms a seal. A sprag washer 60 (see Figure 9) is fitted around the mouth of the socket and is initially secured in position there by means of a screw-threaded cap 62. The initial assembly of the hose 48 to the coupling 52 is similar to that in Figures 1 to 6 in that the hose is simply pushed into the socket with the teeth of the sprag washer riding over the surface of the hose. To disconnect the coupling however the cap 62 is unscrewed, the washer 60 remains in contact with the hose 48 and the cap, the washer and the O-ring remain with the hose.

Reconnection is a simple matter of screwing the cap 62 back onto its thread.

Two possible additional features for providing an enhanced seal are shown in Figures 10 and 11. In Figure 10, an interference bead 64 is moulded into the in ternal surface of the socket in the body part 54 to provide some measure of sealing against the outer surface of the hose 48 to back up the O-ring seal 58.

In Figure 11, the main body part 54 is extended at 66 to meet an annular ridge 68 on the cap 62. When the cap is fully tightened, the extension 66 will make contact with the ridge 68 to form a secondary seal.

The embodiments shown in Figures 12 and 13 have an additional component in the form of metal or plastic ring 70 (see Figure 14) which is a tight fit around the hose 48 and is split at one point 71 around its circumference. In Figure 12, the ring 70 is in place in the main body part 54 before the hose is inserted. Also in this case the internal diameter of the sprag washer, ie the diameter of the open hole defined by the inner tips of the teeth, is slightly larger than the external diameter of the hose 48. The hose 48 can therefore be pushed through the sprag washer without the teeth of the washer damaging the surface of the hose. The hose however will be gripped tightly by the ring 70 on insertion.If the hose then is pulled, the ring 70 will move with the hose and will be pushed against the teeth of the sprag washer, causing the tips of these teeth to move in a radially inward direction to grip the surface of the hose and to resist withdrawal. As in the previous embodiments, when disconnection is necessary the cap 62 can be unscrewed and then the washer 60a and the ring 70 together with the 0-ring 58 can all be withdrawn as a unit from the main body part 54.

In Figure 13, the ring 70 is in a different position, on the opposite side of the sprag washer 60, and the sprag washer has an internal diameter which does interfere with the external surface of the hose 48.

However when the hose is pushed in it will first be pushed into the ring 70. Because the ring 70 is a tight fit on the hose the ring will move forward with the hose and will push against the washer 60. The force needed to move the ring along the hose, against the friction between the ring and the hose, will be greater than the force needed to lift the teeth of the washer, so that the teeth of the washer are lifted out of the path of travel of the hose as the hose is pushed in. In this way again damage to the surface of the hose during the pushing in action will be avoided.

In all the embodiments described the initial connection of the pipe or hose to the main body of the coupling is accomplished by a simple push-in action which produces a sealed and retained joint. Only a small number of components are required to achieve this objective, and in each case a mechanism is provided which allows the coupling to be disconnected when needed. It is a feature of the invention that when the coupling is disconnected, the retention mechanism 22, 60, 62 remains on the pipe end or on the hose as the case may be. In certain circumstances, it may be desirable for the O-ring 18 to remain with the main body part rather than with the pipe end, on disassembly. In this case, a seal retaining lip 72 can be moulded into the main body part 10 as shown in Figure 15 and this will hold the seal in the seal seat 74 as the pipe end is withdrawn.

Claims

1. A pipe coupling comprising a main body part for connection to a first pipe and having a socket for receiving an end of a second pipe, a seal ring for sealing between the main body part and the second pipe, a retention device at the mouth of the socket which will allow the second pipe to be pushed into the socket but will retain the second pipe against withdrawal, and securing means securing the retention device to the main body part, the securing means being removable from the main body part.

2. A pipe coupling as claimed in Claim 1, wherein the retention device comprises a first part which grips the second pipe and a second part which can be connected to the main body part.

3. A pipe coupling as claimed in Claim 2, wherein the first and second parts of the retention device are formed from a single metal component.

4. A pipe coupling as claimed in Claim 2, wherein the first part and the second part are formed by separate components which cooperate with each other.

5. A pipe coupling as claimed in any one of Claims 2 to 4, wherein the first part of the retention device comprises a plate with a hole through which the end of the second pipe can pass, the periphery of the hole being defined by a plurality of inwardly directed teeth surrounding the hole.

6. A pipe coupling as claimed in Claim 5, wherein the teeth are arranged so that when they lie in the plane of the plate, the circle formed by the inner tips of the teeth has a smaller diameter than the external diameter of the second pipe end, but when the teeth are bent out of the plane of the plate, then the tips of the teeth form a circle of larger diameter than the pipe end circumference.

7. A pipe coupling as claimed in Claim 5 or Claim 6, wherein the retention device is a metal plate and the hole and the teeth are formed by cutting away parts of the metal, and the second part of the retention device is formed by bending over ends of the metal plate and forming apertures in the bent over ends and wherein ears are formed on the main body part and the apertures clip onto the ears.

8. A pipe coupling as claimed in Claim 5 or Claim 6, wherein the first part of the retention device is a sprag washer and the second part is a screwthreaded collar which can screw onto a complementary thread on the main body part and can retain the sprag washer.

9. A pipe coupling as claimed in any preceding claim, wherein the main body part is moulded integrally with the first pipe.

10. A pipe coupling as claimed in any one of Claims 1 to 9, wherein the main body part has an arrangement at its opposite end by means of which a pipe can be attached to the main body part.

11. A pipe coupling as claimed in any preceding claim, wherein a friction ring is incorporated in the coupling and is fitted so that it either acts against the retention device to lift the teeth during insertion action or against the retention device to push the teeth inwards on attempted withdrawal.

12. A pipe coupling as claimed in Claim 11, wherein the friction ring is placed so that the second pipe end passes through the friction ring before passing through the retention device and the teeth of the retention device will normally interfere with the pipe end.

13. A pipe coupling as claimed in Claim 11, wherein the retention device normally has a diameter slightly larger than that of the pipe end, and the pipe end encounters the friction washer after passing through the retention device.

14. A pipe coupling as claimed in any preceding claim, wherein the sealing ring is an ring.

15. A pipe coupling as claimed in any preceding claim, wherein the socket includes a moulded-in interference bead to form a secondary seal between the second pipe and the main body part.

16. A pipe coupling as claimed in Claim 8, wherein a part of the screw threaded collar forms a secondary seal with a corresponding part of the main body part.

17. A pipe coupling as claimed in any preceding claim, wherein the seal ring is retained in the main body part on disassembly of the coupling by a retaining lip which forms part of a seat for the seal ring in the main body part.

18. A pipe coupling substantially as herein described with reference to any one embodiment shown in the accompanying drawings.