AU688478B2

AU688478B2 - A pipe coupling

Info

Publication number: AU688478B2
Application number: AU20030/95A
Authority: AU
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: 1998-03-12
Anticipated expiration: 2015-05-12
Also published as: AU2003095A; GB9509703D0; GB2289316A; GB2289316B; NZ260516A

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION For a Standard Patent

ORIGINAL

9 '9 9 9 9 Name of Applicant: Actual Inventor(s) HANSEN DEVELOPMENTS LTD ALBERT FREDERICK HANSEN Address for Service: WRAY ASSOCIATES, Primary Industry House, 239 Adelaide Terrace, Perth, Western Australia, Australia, 6000.

Attorney code: WR Invention Title: A PIPE COUPLING The following statement is a full description of this invention, including the best method of performing it known to me:i

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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 for coupling one length of pipe to another length of pipe, comprising two body parts each comprising a tubular portion having an end onto which a pipe can be engaged and an external screw thread around a part of each tubular portion spaced from the said end of the coupling -lai i; i' body part, a nut (herein: a pipe nut) threadedly mounted on the tubular portion of each body part, each said pipe nut comprising two concentric bores of different diameters, one of lesser diameter which is sized and threaded to thread on to the tubular portion of the coupling body part and another of greater diameter sized and screw threaded to engage and thread on to the exterior of a pipe engaged on said end of the coupling part so that by rotation of the pipe nut each pipe nut can be moved onto the exterior of a pipe engaged on the end of the coupling body part to thread onto the outside of the pipe, and a ball and socket joint between the two body parts of the coupling and a nut (herein: the centre 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.

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 .13: substantially constant cross-section.

Pipe couplings of the invention maybe 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 S: connecting three pipe ends together.

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:

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Fig. 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, Fig, 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, Fig. 3 shows one of the two body parts of the coupling separate from the other parts of the coupling, and Fig. 3A shows detail of one section of the coupling body part shown in Fig.

3.

o 0 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 Fig. 1. The outer part of each end of the coupling may be formed as a tapered nose 6 and circular "barbs" 7 may be S provided. These barbs 7 will engage into the inside wall of the pipe end 5 to assist in 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 Fig 1 (but not Fig. 2 where only the centre nut 10 is shown and the pipe nuts 9 are removed).

-3- I 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 Fig. I 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 Fig. 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 Fig. 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 enablingthe 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.

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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 I 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 Fig. 2. To hold the body parts 1 and 2 together and the ball and socket joint closed, the centre nut having a two part interior is provided. One side of the centre nut 10 is provided with threads 1 Ga 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.

20. 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

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an annular plastic seal may be moulded into the body part 2 as shown in Fig. 3 which shows a section of the body part 2, and Fig. 4 which shows detail of the plastic seal 13.

The seal 13 is an annular flan 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 1 1 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 tne 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 O0: 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 2"Q: 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 -6coupling 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.

Throughout the specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

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 hereof.

Oe. *0 goS olo o -7i ii' II

Claims

1. A pipe coupling for coupling one length of pipe to another length of pipe, comprising two body parts each comprising a tubular portion having an end onto which a pipe can be engaged and an external screw thread around a part of each tubular portion spaced from the said end of the coupling body part, a nut (herein: a pipe nut) threadedly mounted on the tubular portion of each body part, each said pipe nut comprising two concentric bores of different diameters, one of lesser diameter which is sized and threaded to thread on to the tubular portion of the coupling body part and another of greater diameter sized and screw threaded to engage and thread on to the exterior of a pipe engaged on said end of the coupling part so that by rotation of the pipe nut each pipe nut can be moved onto the exterior of a pipe engaged on the end of the coupling body part to thread onto the outside of the pipe, and a ball and socket joint between the two body :2 parts of the coupling and a nut (herein: the centre 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. a

2. A pipe coupling according to claim 1, wherein one of the body parts of the a coupling carrying the ball of the ball and socket joint comprises an annular flap integral a 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. -8- II

3. A pipe coupling according to either one of claims 1 and 2, wherein the bore of greater diameter of each coupling nut is screw threaded with a thread of the same hand and of a similar pitch to that of the bore of lesser diameter of the coupling nut.

4. A pipe coupling according to any one of claims 1 to 3, wherein the bore of greater diameter is tapered outwardly with an increasing diameter from the interior of the nut.

A pipe coupling according to any one of claims 1 to 4 wherein the screw thread of the greater diameter bore of the coupling nut is of a buttress form.

6. A pipe coupling according to any one of the preceding claims, wherein each ,1.0 said tubular portion terminates in a nose tapered with an increasing diamneter from the ;r leading edge of the nose.

7. A pipe coupling substantially as illustrated in the accompanying drawings and described herein with reference thereto. Dated this Twenty-Ninth Day of December 1997 HANSEN DEVELOPMENTS LTD Applicant Wray Associates SPatent Attorneys for the Applicant Perth, Western Australia -9-