GB1587514A

GB1587514A - Pipe couplings

Info

Publication number: GB1587514A
Application number: GB2803076A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-07-06
Filing date: 1976-07-06
Publication date: 1981-04-08
Also published as: FR2357809B3; DE2730217A1; FR2357809A1; ES460470A1

Description

(54) PIPE COUPLINGS (71) I, WILLIAM MICHAEL CAMERON TOWNS, a British Subject of The Manor House Stretton on Fosse, Moreton in Marsh, Gloucestershire, GL56 95B do hereby declare the invention for which I pray that a Patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to pipe couplings and is concerned with an improved type of coupling between a pipe and a fitting, such as a T-piece or elbow bend, or between two pipes by means of a coupling fitting.

In accordance with the present invention I provide a coupling between a pipe and a fitting having a pipe-receiving end portion affording an internal bearing surface defined by a surface of revolution, the coupling comprising a resilient sealing ring interposed radially between the pipe and said surface of the fitting and located axially between a collar received within the end portion of the fitting and an abutment provided within the end portion of the fitting, the collar and the end portion of the fitting having thereon preformed interengaging projections and recesses so arranged as to enable the collar to be inserted within the end portion of the fitting and held therein in a position in which the collar retains the sealing ring against the abutment, and the pipe itself affording an abutment adjacent to the end thereof within the fitting co-operating with the collar to prevent axial withdrawal of the pipe from the fitting.

The coupling in accordance with the invention can be established by forming the abutment on the pipe, by means of an appropriate tool and such abutment most conveniently comprises a continuous outwardly displaced annular groove at a predetermined distance from the end of the pipe. The sealing ring is then placed over the end of the pipe before the latter is inserted into the fitting or alternatively the sealing ring may be assembled within the fitting before the end of the pipe is introduced.

The collar, which should be placed on the pipe before the abutment is formed on the latter, is then assembled with the fitting so as positively to secure the pipe in the fitting. The interengaging projections and recesses afforded by the end portion of the fitting and by the collar are so designed as to enable the collar, after assembly with the pipe, to be inserted within the end portion of the fitting and retained therein by virtue of the engagement of the projections within the recesses, without it being necessary for any deformation of part of either the collar or the fitting to be performed by the application of any tool.

In one embodiment, the projections are rigid and extend radially outwardly from the collar, and the end portion of the fitting is formed with internal axially extending grooves which accommodate said projections and allow the collar to be inserted axially into the end portion of the fitting, the recesses being formed in the end portion of the fitting at positions circumferentially offset from said grooves so that rotation of the collar through less than 180 about its axis causes said projections to enter said recesses.

The projections may be formed with a stop face adapted to engage an axially extending edge of the recess in such a manner as to resist or prevent rotation of the collar in the direction necessary to displace the projections from the recesses.

In an alternative arrangement, the projections may comprise resilient tongues on the collar adapted to enter recesses formed in the end portion of the tubular fitting, such tongues having lead-in faces arranged to displace the tongues inwardly towards the collar as it is inserted into the end portion of the fitting, and having abutment faces adapted to engage sides of the recesses to prevent axial withdrawal of the collar. The recesses in the end portion of the fitting may extend through the entire thickness of the side wall thereof so as to be open extemally whereby the tongues may be displaced by the application of an appropriate tool in order to release the collar.

Alternatively, the fitting may be formed with inwardly directed resilient tongues adapted to engage in appropriately positioned and shaped recess afforded by the collar, in which case the established coupling cannot be taken apart by simple axial withdrawal of the collar other than by fracture of the tongues.

In either case the recesses could be chamfered at diametrically opposed edges relative to the pipe so as to enable the tongues to be deflected into a releasing position upon relative rotation of the collar and the fitting, thereafter enabling the collar to be withdrawn.

However, in a preferred embodiment the projections are formed on the end portion of the fitting and are directed outwardly, the collar having a concentric outer ring in which said recesses are formed.

Conveniently, said recesses are formed as circumferentially offset lateral extensions of respective axially extending guide-ways formed internally of the outer ring of the collar, each guide-way being adapted to receive one of said projections.

A rib may be formed between one or more of said guide-ways and the lateral extension thereof which serves as the recess of the projections from the recesses. Such rib may be chamfered on the side thereof facing into the guideway to facilitate entry of the projection into the recess when the coupling is assembled.

The fitting is conveniently formed from a synthetic plastics material or any metal which can be suitably pressure die-cast, and the collar may be formed from a similar material. The fitting may comprise a straight pipe connector in which the opposed end portions are adapted to receive respective pipes in alignment with one another. The fitting may also take the form of a T-piece, or an elbow bend. Further, the fitting may comprise an inlet fitting or the like for attachment to, or forming part of, a tank or other similar container to which it is required to attach a pipe.

The invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 shows an end view of a first embodiment of fitting in accordance with the invention; Figure 2 shows a diametral section on the line II-II of Figure 1; Figure 3 shows a rear end view of a collar adapted to be received within the fitting; Figure 4 shows a part-sectioned side view of the collar in the direction of the arrow IV in Figure 3; Figure 5 shows a partial transverse section through an assembled coupling formed by the fitting shown in Figures 1 and 2 with the collar shown in Figures 3 and 4, the section being shown in a diametral plane transverse to that of figure 2; Figures 6 and 7 respectively show in medial section further fittings of a type generally similar to that shown in Figures 1 and 2 but in the form of an elbow and a T-piece; Figure 8 shows an end view of a further embodiment of fitting in accordance with the invention; Figure 9 shows a side view of the fitting shown in Figure 8; Figure 10 shows a rear end view of a collar for use with the fitting shown in Figures 8 and 9; Figure 11 shows a front end view of the collar of Figure 10; Figure 12 shows a section to an enlarged scale on the line XII-XII of Figure 11; Figure 13 shows a section to an enlarged scale on the lines XIII-XIII of Figure 11 with the fitting and pipe in assembled relation with the collar; Figure 14 shows a section on the line XIV XIV of Figure 13 omitting the sealing ring and pipe; Figure 15 shows, in a view similar to Figure 10, a modified collar whereby the coupling can be mounted on the supporting surface, and Figure 16 illustrates in outline only a number of further fittings of the type generally similar to that shown in Figures 8 and 9.

Figures 1 and 2 of the accompanying draings illustrate a straight in-line connector fitting for coupling two tubes of the same diameter together. The fitting comprises a moulded body 10 formed of any suitable synthetic plastics material or as a pressure die casting of a suitable metal. The central portion 11 of the body 10 is of circular shape in section and is formed with a plurality of radially inwardly directed ribs 12 arranged to grip an end portion of a pipe which is inserted into the fitting through either of the end portions 13. Each end portion 13 is formed with a pair of diametrally opposed external lobes 14 which internally define axial grooves 15 extending up to the open ends of the fittings from respective positions spaced axially from the ends of the axial ribs 12. At the inner end of each groove 15, the end portion 13 of the fitting is formed with a recess in the form of a through slot 16, the slots being circumferentially offset from the respective grooves 15 in the clockwise direction as viewed in Figure 1.

Between the ribs 12 and the inner ends of the grooves 15, each end portion 13 affords an internal bearing surface 17 formed as a surface of revolution to engage a sealing ring as here inafter described.

The collar 20 shown in Figures 3 and 4 includes an end flange 18 which is similar in shape to the open ends of the fitting 10, and a tubular portion 21 is formed externally with a pair of diametrially opposed projections 22.

The projections extend circumferentially and are so spaced from the flange 18 that they may engage within the slots 16 of the fitting 10.

Each projection 22 includes face 23, which is tangental to the tubular portion 21, an arcuate face 24 and a stop face 25. The tubular portion 21 is formed with an internal rebate 26 at the end thereof remote from the flange 18, the rebate merging smoothly with the intemal diameter of the tubular portion through a generally S-shaped surface 27. The tubular portion 21 is also slightly rebated externally as indicated at 28, and the end face 29 is angled obliquely as shown.

Additionally, four recesses 19 are formed around the open mouth of the collar 20 for the purpose hereinafter mentioned.

In use, the collar 20 is slipped onto the end of a tube 30, and thereafter an outwardly directed circumferentially extending groove 31 is formed therein by means of a suitably designed tool, the groove being situated at a predetermined distance from the end of the pipe. The profile of the groove 31 corresponds to that of the internal rebate 26 and the collar can be pushed outwardly along the pipe until the groove 31 is engaged within this rebate as shown in Figure 5. The pipe and collar can then be inserted into the end portion 14 of the fitting 10, with a sealing ring 32 either being positioned within the fitting 10 or on the pipe 30.

The projections 22 can pass axially along the grooves 15 until the collar 20 is fully inserted into the end portion 14 with the flange 18 substantially abutting the end face of the fitting.

Thereafter, the collar can be rotated by means of an appropriate tool having prongs adapted to engage within the recesses 19 so that the projections 22 enter the slots 16. The tangential face 23 is formed at the leading end of each projection to facilitate the entry thereof into the corresponding slot. The radius of the arcuate surface 24 is preferably such that it bears on the edge 16a and affords a resistance to rotation and requires some elastic deformation of the projection. Thus, on completion of rotation, the projection "snaps-in" and the stop face 25 of the projection is then disposed in face-to-face relation with the end face 16b of the slot 16. This then affords a positive abutment against contra-rotation of the collar, and preferably the abutment face 15 is angled so as to be arranged substantially parallel to the end face 1 6b of the slot.

As can be seen from Figure 5, the sealing ring 32 is so dimensioned as to be placed in radial compression between the bearing surface 17 of the fitting and the external surface of the pipe 30 whilst it is held axially between the end face 29 of the collar and the abutment afforded by the groove 18 formed in the tubing, on the one hand, and an internal circumferential abutment face 33 afforded by the ends of the ribs 12 within the body 11 of the fitting. If desired the ring 32 may be subject to axial compression by suitably dimensioning the collar and the fitting.

Despite the tolerances necessary in the manufacture of the fitting and the collar, as well as the tolerances in the production of the moulded plastics material from which the coupling components are preferably formed makes it possible for a secure and pressure-tight coupling to be established reliably.

In an alternative embodiment as previously mentioned, the projections 22 may be replaced by resilient tongues adapted to snap outwardly into the recesses 16 and in this case the grooves 15 would be omitted. In a further alternative such tongues could be provided on the fitting to enter recesses in the collar.

If it is desired to enable such a coupling to be released non-destructively, one axially directed edge of each recess and/or tongue could be so chamfered as to enable the tongue to be displaced to a releasing position clear of the recess upon relative rotation of the collar and the fitting in the opposite direction to that in which the two components were rotated in assembly of the coupling.

As mentioned previously, the fitting may be formed as an elbow junction 10a or a T-piece lOb as shown in Figures 6 and 7 respectively.

In Figures 6 and 7 parts identical to those already described are indicated by the use of the same reference numerals and no further description of such parts is deemed necessary.

As can be seen in Figure 6, the elbow junction 10a includes end portions 13 generally similar to those shown in Figures 1 and 2, but the central portion 1 la of the body is of curved form so that the two end portions 13 are disposed perpendicularly transverse relative to one another. Radially inwardly directed ribs 12a are provided adjacent to each end portion 13, but do not in this case extend through the whole of the central portion 1 la.

The T-piece lOb shown in Figure 7 may be considered as an extended in-line connector with a lengthened central portion 1 lib as compared with that of the connector shown in Figures 1 and 2, the central portion 1 lb having end portions 13 identical with those previously described. However, in this case the central portion 1 ib of the body lOb is formed with a lateral branch 1 1c having an additional end portion 1 3b identical to those previously described so that three pipes may be coupled in a T-junction. Internal ribs 12b are formed in the lateral branch l 1c as shown.

As a further alternative the fitting may be a single end fitting, for example, an inlet to a tank. Where the fitting is designed for coupling two or more pipes together, it is not necessary that all the pipes should be of the same external diameter. The fitting may also be especially adapted for wall mounting, for example by affording one flat face formed with grooves adapted to co-operate with a suitable mounting bracket.

Referring now to Figures 8 to 16 of the accompanying drawings, there is illustrated therein a further, preferred embodiment of coupling in accordance with the invention. A straight in-line connector fitting 50 is illustrated in Figures 8 and 9, and as can be seen this is of a substantially simpler form than the previously described fitting 10. Again, it takes the form of a body with a central portion 51 and two end portions 52, but in this case the internal surface 5 la of the central portion 51 is smooth and of an intemal diameter just sufficient to receive a pipe of the diameter for which the coupling is intended.

The end portions 52 are internally and exter nally of greater diameter than the central portion 51 and each affords an internal shoulder or abutment face 53 at its inner end. Externally, each end portion 52 is formed with four outwardly directed projections 54 arranged in two diametrally opposed pairs. As can be seen best in Figure 9, each projection 54 includes an inner end face 55 which is inclined at an acute angle to a plane perpendicular to the longitudinal centre line of the fitting so that the width of each projection 54 as measured in a direction parallel to the longitudinal centre-line of the fitting increases progressively in a clockwise direction as viewed from the adjacent end of the fitting.

In this embodiment, each end portion 52 is adapted to receive a cap member 60 as shown particularly in Figures 10 to 12. The cap member 60 includes a sleeve or collar 61 which is generally similar to the tubular portion 21 of the collar 20 of the previously described embodiment. In particular, the collar 61 includes an internal rebate 66 at the inner end thereof, but in this case the face 67 is of frustoconical form and not S-shaped as the surface 27. The end face 69 is angled obliquely as seen best in Figure 12.

The cap member 60 also includes an outer ring 62 concentric with the collar 61. The outer ring is formed internally with four axially extending guide-ways 63 each of circumferential width adapted to receive therein a respective one of the projections 54 on the end portions 52 of the fitting 50. Each guide-way 63 is spaced circumferentially apart from its neighbour by a raised land 64 which is of slightly increasing radial thickness in the direction away from the free edge 65 of the outer ring 62.

Each guide-way 63 is formed at its innermost end with a laterally offset extension 70 so dimensioned as to receive a respective one of the projections 54 when the cap member 60 is rotated anti-clockwise relative to the fitting 50 after the two have been assembled together by sliding the projections 54 along the guide-ways 63. The edge 71 of the land 64 is inclined at an angle complementary to that of the face 55 of the projections, and the extension 70 terminates in a raised portion 72 which is formed as an extension of the land 64. For convenience of manufacture, the extension 70 extends up to the end face 73 of the cap member 60, which is accordingly formed with four openings 74.

In order to afford resistance to disassembly of the coupling, ribs 75 are formed internally of the outer ring 62 at the entrance to at least two of the lateral extensions 70 of the guideways 63. Preferably, as shown, these ribs include a chamfered face 76 directed towards the guide-ways and a more steeply inclined face 77 directed towards the extensions 70 so that greater resistance is offered to movement of the projections 54 out of the extensions and back into the guide-ways than in the opposite direction.

The complete coupling is shown in Figure 13 and as can be seen the groove 31 in the pipe 30 seats in the rebate 66 of the collar 61, and the sealing ring 32 is trapped between the abutment face 53 of the fitting 50 on the one hand and the end face 69 of the collar and the groove 31 on the ring on the other hand to form an effective seal.

In the modifcation shown in Figure 15, there is shown a cap member 60a which is generally similar to the cap members 60 previously described, and parts identical to those already described are indicated by the use of the same reference numerals so that no further description is deemed necessary. However, the outer ring is formed with a pair of parallel ears 62a with inwardly curved end portions 62b adapted to engage under protuberences 59 formed at the free edges of longitudinal flanges 58 provided at the edges of a mounting plate 57 which is adapted to be secured to a suitable supporting surface, for example by means of one or more screws. Inbetween the two ears 62a, the outer ring of the modified cap member 60a is formed with a projection 62c which is adapted to engage the mounting plate 57 as shown in Figure 15.

As with the first embodiment as described in Figures 1 to 5 of the accompanying drawings, the embodiment shown in Figures 8 to 14 may also be formed as an elbow junction or a Tpiece, and in Figure 16 there is shown a fragmentary portion of a pipe system whereby a pipe 30a is connected to pipe 30b by means of an elbow junction which comprises a body 50a generally similar to the fitting 50 shown in Figures 8 and 9, except that the central portion 5 la thereof is of relatively increased length and is bent through a right-angle so that the two end portions 52 of the fitting are disposed at right-angles to one another. The pipe 30b is connected to a further in-line pipe 30c through a T-piece 50b which includes a lateral branch 50c leading to an additional end portion whereby a further pipe 30d branches off.

It will be appreciated that the fittings and cap members may be made in a range of sizes to suit differing diameters of pipe, and that additionally adaptor fittings may be made wherein one or more of the end portions 52 are adapted for use with pipes of a different diameter from the remaining end portion or portions.

WHAT I CLAIM IS: 1. A coupling between a pipe and a fitting having a pipe-receiving end portion affording an internal bearing surface defined by a surface of revolution, the coupling comprising a resilient sealing ring interposed radially between the pipe and said surface of the fitting and located axially between a collar received with the end portion of the fitting and an abutment provided within the end portion of the fitting, the collar and the end portion of the fitting having thereon prefonned interengaging projections and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. nally of greater diameter than the central portion 51 and each affords an internal shoulder or abutment face 53 at its inner end. Externally, each end portion 52 is formed with four outwardly directed projections 54 arranged in two diametrally opposed pairs. As can be seen best in Figure 9, each projection 54 includes an inner end face 55 which is inclined at an acute angle to a plane perpendicular to the longitudinal centre line of the fitting so that the width of each projection 54 as measured in a direction parallel to the longitudinal centre-line of the fitting increases progressively in a clockwise direction as viewed from the adjacent end of the fitting. In this embodiment, each end portion 52 is adapted to receive a cap member 60 as shown particularly in Figures 10 to 12. The cap member 60 includes a sleeve or collar 61 which is generally similar to the tubular portion 21 of the collar 20 of the previously described embodiment. In particular, the collar 61 includes an internal rebate 66 at the inner end thereof, but in this case the face 67 is of frustoconical form and not S-shaped as the surface 27. The end face 69 is angled obliquely as seen best in Figure 12. The cap member 60 also includes an outer ring 62 concentric with the collar 61. The outer ring is formed internally with four axially extending guide-ways 63 each of circumferential width adapted to receive therein a respective one of the projections 54 on the end portions 52 of the fitting 50. Each guide-way 63 is spaced circumferentially apart from its neighbour by a raised land 64 which is of slightly increasing radial thickness in the direction away from the free edge 65 of the outer ring 62. Each guide-way 63 is formed at its innermost end with a laterally offset extension 70 so dimensioned as to receive a respective one of the projections 54 when the cap member 60 is rotated anti-clockwise relative to the fitting 50 after the two have been assembled together by sliding the projections 54 along the guide-ways 63. The edge 71 of the land 64 is inclined at an angle complementary to that of the face 55 of the projections, and the extension 70 terminates in a raised portion 72 which is formed as an extension of the land 64. For convenience of manufacture, the extension 70 extends up to the end face 73 of the cap member 60, which is accordingly formed with four openings 74. In order to afford resistance to disassembly of the coupling, ribs 75 are formed internally of the outer ring 62 at the entrance to at least two of the lateral extensions 70 of the guideways 63. Preferably, as shown, these ribs include a chamfered face 76 directed towards the guide-ways and a more steeply inclined face 77 directed towards the extensions 70 so that greater resistance is offered to movement of the projections 54 out of the extensions and back into the guide-ways than in the opposite direction. The complete coupling is shown in Figure 13 and as can be seen the groove 31 in the pipe 30 seats in the rebate 66 of the collar 61, and the sealing ring 32 is trapped between the abutment face 53 of the fitting 50 on the one hand and the end face 69 of the collar and the groove 31 on the ring on the other hand to form an effective seal. In the modifcation shown in Figure 15, there is shown a cap member 60a which is generally similar to the cap members 60 previously described, and parts identical to those already described are indicated by the use of the same reference numerals so that no further description is deemed necessary. However, the outer ring is formed with a pair of parallel ears 62a with inwardly curved end portions 62b adapted to engage under protuberences 59 formed at the free edges of longitudinal flanges 58 provided at the edges of a mounting plate 57 which is adapted to be secured to a suitable supporting surface, for example by means of one or more screws. Inbetween the two ears 62a, the outer ring of the modified cap member 60a is formed with a projection 62c which is adapted to engage the mounting plate 57 as shown in Figure 15. As with the first embodiment as described in Figures 1 to 5 of the accompanying drawings, the embodiment shown in Figures 8 to 14 may also be formed as an elbow junction or a Tpiece, and in Figure 16 there is shown a fragmentary portion of a pipe system whereby a pipe 30a is connected to pipe 30b by means of an elbow junction which comprises a body 50a generally similar to the fitting 50 shown in Figures 8 and 9, except that the central portion 5 la thereof is of relatively increased length and is bent through a right-angle so that the two end portions 52 of the fitting are disposed at right-angles to one another. The pipe 30b is connected to a further in-line pipe 30c through a T-piece 50b which includes a lateral branch 50c leading to an additional end portion whereby a further pipe 30d branches off. It will be appreciated that the fittings and cap members may be made in a range of sizes to suit differing diameters of pipe, and that additionally adaptor fittings may be made wherein one or more of the end portions 52 are adapted for use with pipes of a different diameter from the remaining end portion or portions. WHAT I CLAIM IS:

1. A coupling between a pipe and a fitting having a pipe-receiving end portion affording an internal bearing surface defined by a surface of revolution, the coupling comprising a resilient sealing ring interposed radially between the pipe and said surface of the fitting and located axially between a collar received with the end portion of the fitting and an abutment provided within the end portion of the fitting, the collar and the end portion of the fitting having thereon prefonned interengaging projections and

recesses so arranged as to enable the collar to be inserted within the end portion of the fitting and held therein in a position in which the collar retains the sealing ring against the abutment, and the pipe itself affording an abutment adjacent to the end thereof within the fitting co-operating with the collar to prevent axial withdrawal of the pipe from the fitting.

2. A coupling according to Claim 1 wherein the projections are rigid and extend radially outwardly from the collar, and the end portion of the fitting is formed with internal axially extending grooves which accommodate said projections and allow the collar to be inserted axially into the end portion of the fitting, the recesses being formed in the end portion of the fitting at positions circumferentially offset from said grooves so that rotation of the collar through less than 180 about its axis causes said projections to enter said recesses.

3. A coupling according to Claim 2 wherein the projections are formed with a stop face adapted to engage an axially extending edge of the recess in such a manner as to resist or prevent rotation of the collar in the direction necessary to displace the projections from the recesses.

4. A coupling according to Claim 1 wherein the projections comprise resilient tongues on the collar adapted to enter recesses formed in the end portions of the tubular fitting, such tongues having lead-in faces arranged to displace the tongues inwardly towards the collar as it is inserted into the end portion of the fitting, and having abutment faces adapted to engage sides of the recesses to prevent axial withdrawal of the collar.

5. A coupling according to Claim 1 wherein the fitting is formed with inwardly directed resilient tongues adapted to engage in appropriately positioned and shaped recesses afforded by the collar, in which case the established coupling cannot be taken apart by simple axial withdrawal of the collar other than by fracture of the tongues.

6. A coupling according to Claim 1 wherein the projections are formed on the end portion of the fitting and are directed outwardly, the collar having a concentric outer ring in which said recesses are formed.

7. A coupling according to Claim 6 wherein the outer ring of the collar is fonned internally with axially extending guide-ways each adapted to receive a respective one of the projections on the end portion of the fitting, said guideways respective circumferentially offset lateral extensions which define said recesses.

8. A coupling according to Claim 7 wherein a rib is formed between one or more of said guide-ways and the lateral extension thereof for the purpose of providing resistance to withdrawal of the projections from the recesses.

9. A coupling according to Claim 8 wherein said rib is chamfered on the side thereof facing into the guide-way to facilitate entry of the projection into the recess.

10. A coupling according to any one of the preceding claims wherein the fitting comprises a straight pipe connector in which the opposed end portions are adapted to receive respective pipes in alignment with one another.

11. A coupling according to any one of Claims 1 to 9 wherein the fitting is in the form of a T-piece affording three end-portions for the reception of respective pipes.

12. A coupling according to any one of Claims 1 to 9 wherein the fitting is in the form of an elbow bend and the opposed end portions thereof are disposed mutually transverse to one another for the reception of pipes extending in transverse directions.

13. A coupling according to any one of the Claims 1 to 9 wherein the fitting comprises a single ended inlet fitting for attachment to, or forming part of, a tank or other container to which it is required to attach a pipe.

14. A pipe coupling substantially as hereinbefore described with reference to and as shown in Figures 1 to 5 of the accompanying drawings.

15. A pipe coupling substantially as hereinbefore described with reference to and as shown in Figure 6 of the accompanying drawings.

16. A pipe coupling substantially as hereinbefore described with reference to and as shown in Figure 7 of the accompanying drawings.

17. A pipe coupling substantially as hereinbefore described with reference to and as shown in Figures 8 to 14 of the accompanying drawings.

18. A pipe coupling substantially as hereinbefore described with reference to and as shown in Figure 15 of the accompanying drawings.

19. A pipe coupling substantially as hereinbefore described with reference to and as shown in Figure 16 of the accompanying drawings.