GB2289316A

GB2289316A - Pipe coupling

Info

Publication number: GB2289316A
Application number: GB9509703A
Authority: GB
Inventors: Albert Frederick Hansen
Original assignee: Hansen Developments Ltd
Current assignee: Hansen Developments Ltd
Priority date: 1994-05-12
Filing date: 1995-05-12
Publication date: 1995-11-15
Anticipated expiration: 2015-05-12
Also published as: AU688478B2; AU2003095A; GB9509703D0; GB2289316B; NZ260516A

Abstract

A pipe coupling has two body parts (1) and (2). One or both comprise a tubular portion having an end (6) onto which a pipe can be engaged and an external screw thread (8) around a part of each tubular portion, to receive a pipe nut (9) which by rotation can be moved onto the exterior of a pipe (5) engaged on the end of the coupling to clamp the pipe. There is a ball and socket joint (11, 12) between the two body parts (1, 2) of the coupling and a centre nut (10) captive around and against one of the body parts and screwed partly onto the other body part to hold the two together, so that the two body parts can swivel relative to one another. The ball (12) of the ball and socket joint may comprise an annular flap (13) integral with and around the ball and an annular undercut beneath the flap, which form a fluid tight seal against the socket of the other body part. <IMAGE>

Description

PIPE COUPLING The invention comprises a pipe coupling.

New Zealand patent 195771/200149 describes a pipe coupling for polythene or alkathene pipe which has been particularly successful commercially. Alkathene and polythene piping is typically used in agricultural irrigation systems either simply laid on the ground around an orchard for example, or buried in the ground, and in various other agricultural and non-agricultural applications. Alkathene and polythene pipes generally have a hard wall and are semi-rigid and require particular techniques for coupling which are different from methods of coupling either soft walled pipes such as garden hose piping for example, or metal piping.

The coupling of New Zealand patent 195771/200149 in the case of a "straight" coupling comprises a body consisting of a central section, and ends on either side of the central section onto which on each side a pipe end is engaged. The coupling has coupling nuts which are threadedly mounted one on each end of the coupling so that the coupling nut on each end can be wound on to the exterior of a pipe end pushed onto the coupling to mechanically link the pipe end to the coupling.

The present invention provides an improved or at least alternative form of pipe coupling.

In broad terms the invention comprises a pipe coupling comprising two body parts, at least one comprising a tubular portion having an end onto which a pipe can be engaged, an external screw thread around a part of the or each tubular portion spaced from the adjacent end of the coupling, a respective pipe nut threadedly mounted on the or each said screw thread so that by rotation of the or each pipe nut it can be moved onto the exterior of a pipe engaged on the end of the coupling to clamp the pipe, a ball and socket joint between the two body parts of the coupling and a coupling nut captive around and against one of the body parts and screwed partly onto the other body part to hold the two body parts together, the coupling comprising a hollow interior for fluid flow through the coupling including the end(s) of the coupling and said ball and socket joint.

Preferably, one of the body parts of the coupling carrying the ball of the ball and socket joint comprises an annular flap integral with and around said ball and an annular undercut beneath the flap, which forms a fluid tight seal against the socket of the other body part.

Preferably each pipe nut comprises two substantially concentric bores of different diameters, one of lesser diameter which is sized and threaded to thread onto the coupling body and another bore of greater diameter which is also preferably screw threaded (with a thread of the same hand and a similar pitch) so that it will thread onto the outside of the pipe. Instead of being threaded the outer part of the nut which moves onto the pipe end could be plain to simply clamp the pipe in place, but it is preferred that it is threaded to give a stronger coupling to the pipe. The larger diameter or outer bore of the pipe nut may be tapered outwardly with an increasing diameter from the interior of the nut, or less preferably may be of substantially constant crosssection.

Preferably, the screw thread of the greater diameter bore of the or each pipe nut and/or the coupling nut is of a buttress form.

Preferably, the or each said tubular portion terminates in a respective nose tapered with an increasing diameter from the leading edge of the nose.

Preferably, each of said body parts comprises a said tubular portion with an end on to which a pipe can be engaged and an external screw thread carrying a said coupling nut, for coupling one length of pipe to another length of pipe.

Pipe couplings of the invention may be formed as "straight" couplings which are used to couple two pipe ends together in line. Alternatively pipe couplings of the invention may be formed as "elbows" i.e. right angles or similar, T's i.e. a coupling for connecting three pipe ends together, or as a coupling to connect a pipe end to a piece of equipment such as a pump or similar.

The invention will be further described with reference to the accompanying drawings which show a preferred form coupling of the invention, by way of example.

In the Drawings: Figure 1 shows the preferred form coupling which is a "straight" coupling, partly in cross section showing the end of a length of pipe connected to one side of the coupling; Figure 2 shows the coupling with the two body parts of the coupling separated showing also the centre nut for connecting to two body parts of the coupling together but with the two pipe nuts which connect to the pipe on either end of the coupling removed; Figure 3 shows one of the two body parts of the coupling separate from the other parts of the coupling; and Figure 3a shows detail of one section of the coupling body part shown in Figure 3.

The coupling comprises two body parts indicated at 1 and 2. Each of the body parts 1 and 2 comprises a tubular portion 3 having an end 4 onto which the end of a pipe 5 can be engaged as shown on the left hand side of Figure 1. The outer part of each end of the coupling may be formed as a tapered nose 6 and circular "barbs" 7 may be provided. These barbs 7 will engage into the inside wall of the pipe end 5 to assist in holding the pipe securely on the coupling.

The exterior of each tubular portion 3 is threaded adjacent the centre of the coupling as shown at 8 to mount a pipe nut 9. In a "straight" coupling such as shown in the drawings, a pipe nut 9 is provided on either side of the coupling as shown in Figure 1 ( but not Figure 2 where only the centre nut 10 is shown and the pipe nuts 9 are removed). Each pipe nut 9 is threadedly mounted to the threaded part 8 of the body of the coupling by threads on the inner part 9a of the pipe nut, and each also comprises an outwardly tapered part carrying threads 9b which in use engage the exterior of the pipe end 5 as shown in Figure 1 on the left hand side.

In use of the coupling to connect a pipe end to one side of the coupling first the coupling nut 9 on that side is screwed back on to the coupling as far as it can go, as shown on the right hand side of Figure 1. The pipe end is then pushed onto the nose 6 and then further onto the end of the coupling over the barbs 7, to the position in which the pipe end 5 is shown on the left hand side of Figure 1. The pipe nut 9 is then rotated to screw the nut towards the end of the coupling and as the pipe nut moves it will screw onto the outside of the pipe end and the threads 9b of pipe nut 9 will bite into and thread onto the exterior of the pipe end to form a strong mechanical connection to the pipe. Preferably the threads 9b are formed with a shark tooth or buttress thread to further prevent the pipe from being pulled off the end of the coupling.

The interior of the pipe nut 9 may be of a constant diameter but it is preferred that the outer part carrying the threads 9b is tapered outwardly as shown which assists in enabling the coupling to accommodate pipes of different wall thicknesses. Also, instead of providing threads 9b on the outwardly tapered part of the pipe nut 9, the outer tapered part of the pipe nut may simply be unthreaded e.g. smooth or provided with a roughened surface to engage the exterior of the pipe end, but it is preferred to provide threads as indicated at 9b and described above. The threads 9b should be of the same hand and of a similar pitch to the threads 9a.

The two coupling body parts 1 and 2 are connected by a ball and socket type joint and a centre nut 10 captive on the body part 1 and screwed partly onto the body part 2 as shown to hold the coupling body parts 1 and 2 together. The end 11 of the body part 1 is formed as a socket to receive the end 12 of the body part 2 which is formed as a ball or part ball, the parts being shaped generally as shown - see Figure 2. To hold the body parts 1 and 2 together and the ball and socket joint closed, the centre nut 10 having a two part interior is provided. One side of the centre nut 10 is provided with threads 10a as shown which screw onto a threaded boss 14 on the body part 2 as shown. The other side of the centre nut 10 is smooth and is of a complementary shape to the exterior of the socket end 11 of the coupling body part 1. The centre nut is captive against this end 11 the body part 1 and screws onto the threaded boss 14 of the other coupling part 2 to hold the two body parts of the coupling together, but at the same time allowing the body part 1 to pivot or swivel somewhat relative to the body part 2 when the centre nut is slightly loosened, so that the two body parts of the coupling do not necessarily need to be exactly axially aligned. For example, before the centre nut 10 is fully tightened, the body part 1 may be moved e.g. 5 degrees off centre from the body part 2 and then the nut 10 tightened to hold the two body parts of the coupling together at this angle.

This is useful for connecting pipe ends which themselves are not directly axially aligned.

A steel ring 15 may be provided about the centre nut 10 as shown to provide added strength against fluid pressure from within the coupling.

An O-ring 13 (not shown) may be provided around the end of the body part 2 which engages into the body part 1 to assist in providing a fluid tight seal.

Alternatively an annular plastic seal may be moulded into the body part 2 as shown in Figure 3 which shows a section of the body part 2, and Figure 3a which shows detail of the plastic seal 13. The seal 13 is an annular flap with an adjacent undercut which is an integral part of the body part 2 as shown. In use when the body parts 1 and 2 are brought together and the centre nut 10 is screwed tight, the seal will contact the end 11 of the body part 1 to form a fluid tight seal.

In use of the coupling the centre nut 10 may be completely unscrewed so that the body parts 1 and 2 of the coupling are disconnected. The body part 1 is then connected to one pipe end, by screwing back the pipe nut 9, pushing the coupling part into the pipe end, and screwing the nut 9 forward to engage the pipe. The body part 2 is then similarly entered into the other pipe end and the pipe nut 9 thereof screwed forward to connect to that pipe end. The two body parts 1 and 2 of the coupling connected to the two pipe ends are then brought together and the centre nut 10 screwed on to the threaded boss 14 of the coupling part 2 and tightened to hold the parts of the coupling together and finish the connection.

As stated, it is not essential that the two pipe ends be directly axially aligned, and a benefit of the coupling of the invention is that it allows pipe ends which may be lying at a slight angle to one another to be coupled together. It is not always practical to move the pipes themselves which may comprise heavy piping of large diameter or alternatively the pipe may be buried pipe where there is limited room to move.

The preferred form coupling shown in the drawings and described above is a "straight" coupling but it is also possible that couplings of the invention may be formed in other configurations. For example in the case of an "elbow" coupling the coupling part 2 may be formed with a bend of any desired angle between the threaded boss 14 and the threaded part 8. Similarly, couplings of the invention may be formed as T's. It is also possible that the coupling may be a coupling to couple a pipe end to a piece of equipment such as a pump - in this case for example the body part 2 of the coupling instead of comprising the tubular portion with nose 6, barbs 7 and threaded exterior 8 carrying the coupling nut 9 on that side of the coupling may simply have a standard thread which threads into the inlet or outlet fitting of the pump or other piece of equipment.

The foregoing describes the invention including a preferred form thereof. Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated within the scope thereof.

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 embodiments. The 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.

Claims

1. A pipe coupling comprising two body parts, at least one comprising a tubular portion having an end onto which a pipe can be engaged, an external screw thread around a part of the or each tubular portion spaced from the adjacent end of the coupling, a respective pipe nut threadedly mounted on the or each said screw thread so that by rotation of the or each pipe nut it can be moved onto the exterior of a pipe engaged on the end of the coupling to clamp the pipe, a ball and socket joint between the two body parts of the coupling and a coupling nut captive around and against one of the body parts and screwed partly onto the other body part to hold the two body parts together, the coupling comprising a hollow interior for fluid flow through the coupling including the end(s) of the coupling and said ball and socket joint.

2. A pipe coupling according to claim 1, wherein one of the body parts of the coupling carrying the ball of the ball and socket joint comprises an annular flap integral with and around said ball and an annular undercut beneath the flap, which forms a fluid tight seal against the socket of the other body part.

3. A pipe coupling according to either one of claims 1 or 2, wherein the or each pipe nut comprises two substantially concentric bores of different diameters, one of lesser diameter which is sized and threaded to thread on to the coupling body and another bore of greater diameter sized to engage the exterior of said pipe engaged on the end of the coupling to clamp the pipe.

4. A pipe coupling according to claim 3, wherein the or each bore of greater diameter is screw threaded with a thread of the same hand and of a similar pitch to that of the bore of lesser diameter to thread on to the outside of the pipe.

5. A pipe coupling according to either one of claims 3 or 4, wherein the or each bore of greater diameter is tapered outwardly with an increasing diameter from the interior of the nut.

6. A pipe coupling according to either one of claims 4 or 5 wherein the screw thread of the greater diameter bore of the or each pipe nut and/or the coupling nut is of a buttress form.

7. A pipe coupling according to any one of the preceding claims, wherein the or each said tubular portion terminates in a respective nose tapered with an increasing diameter from the leading edge of the nose.

8. A pipe coupling according to any one of the preceding claims, wherein each of said body parts comprises a said tubular portion with an end on to which a pipe can be engaged and an external screw thread carrying a said coupling nut, for coupling one length of pipe to another length of pipe.

9. A pipe coupling substantially as illustrated in the accompanying drawings and described herein with reference thereto.

10. A pipe coupling substantially as hereinbefore described.