AU2009213048A1

AU2009213048A1 - A Swivel joint assembly for coupling two conduits to each other

Info

Publication number: AU2009213048A1
Application number: AU2009213048A
Authority: AU
Inventors: Andrew Hobbs
Original assignee: Plastec Australia Pty Ltd
Current assignee: Plastec Australia Pty Ltd
Priority date: 2009-09-10
Filing date: 2009-09-10
Publication date: 2011-03-24
Anticipated expiration: 2029-09-10
Also published as: AU2009213048B2; NZ587885A

Description

1 A SWIVEL JOINT ASSEMBLY FOR COUPLING TWO CONDUITS TO EACH OTHER FIELD OF THE INVENTION This invention relates a swivel joint assembly for coupling two conduits to each other 5 such that they are in flow communication with each other. The invention extends to a pipeline installation including the swivel joint assembly and to an adaptor for a swivel joint assembly. The Applicant has found that this invention has particular application, but not exclusive 10 application, to underground drainage piping installations for domestic drainage systems, e.g. storm water and sewerage drain pipe installations that are received within the ground. It will therefore be convenient to hereinafter describe the invention with reference to this example application. However, the invention can also be employed on other conduit installations, including above ground conduit installations 15 and conduit installations other than those related to domestic plumbing installations. BACKGROUND TO THE INVENTION Some pipe installations can be received within the ground. For example, domestic drainage pipes, such as sewerage pipes and waste water pipes, extending from a 20 structure to a sewerage main are typically received in the ground. A pipeline installation that is received within the ground can be exposed to external forces. For example the settling of soil and gravel surrounding one or more pipes of the pipeline installation may cause the application of a force to the pipe. Further, soils 25 may expand and contract in response to conditions within the soils, particularly in response to changes in moisture content within the soil. This expansion and contraction may cause the application of a force to one or more pipes. The expansion and contraction can also cause movement, e.g. lifting of the surrounding structure such as a concrete slab, and this movement may impose stresses on the pipes of a 30 pipeline installation. The external forces imposed on the installed drainage pipes may urge the installed drainage pipes to move relative to each other from their initially installed positions in 2 which they are aligned. In the absence of a mechanism for these forces to be relieved, e.g. by movement of the installed drainage pipes, continuous stresses will be applied to the drainage pipes and the pipe joints coupling the drainage pipes to each other. The stresses on the drainage pipes may lead to cracking and breakage of the 5 pipes and the pipe joints. This may result in the leakage of liquid, e.g. fluid egress from the pipe and/or the entry of external matter, e.g. unwanted infiltration from the outside into the pipe. Consequently when such a breakage is detected the damaged pipes need to be repaired. Due to the fact that the pipe is received within the ground, e.g. 1-2m below the ground surface and the damaged pipe is not visible from the 10 surface the excavation of the surrounding earth and the repair of the pipe can be a difficult and arduous process. One way in which this problem has been mitigated at least to some extent is to install a swivel joint inline with the pipes that permits angular movement of the pipes relative 15 to each other. However a pivoting or a swiveling of a swivel joint may be restricted by a pipe installation if the pipes are not able to compensate for longitudinal extension or retraction of the pipes. Clearly it would be advantageous if a contrivance could be devised for coupling 20 conduits, in particular drainage pipes, in flow communication with each other in such a way as to relieve at least some of the stresses imposed on the pipes and pipe joints. SUMMARY OF THE INVENTION According to one aspect of the invention there is provided a swivel joint assembly for 25 coupling two tubular conduits to each other in flow communication with each other, which includes: a tubular swivel joint member having one swivel joint formation; 30 a tubular adaptor including a complementary swivel joint formation that is complementary to said one swivel joint formation; and a displaceable tubular member that is operatively coupled to said tubular adaptor such that it is in flow communication therewith, wherein the displaceable 3 tubular member is telescopically displaceable relative to the tubular adaptor whereby to render the joint assembly axially expansible as well as capable of a swiveling action. 5 The displaceable tubular member may be received within the tubular adaptor. Alternatively the displaceable tubular member may circumferentially surround the tubular adaptor and be telescopically displaceable over the outside of the tubular adaptor. 10 The one swivel joint formation on the tubular swivel joint member (that is separate from said adaptor) may be one of a spigot or socket formation and the complementary swivel joint formation on the adaptor may be the other of a spigot or socket formation. The tubular adaptor may include a tubular bore having a bore inner surface, and the 15 displaceable tubular member may be an inner tubular member that is received within the tubular bore and is telescopically displaceable within the tubular bore. In this specification the term "bore" is to be interpreted broadly and refers to an internal wall that receives and engages with the inner tubular member. It is not limited 20 to a bore of cylinder and in particular does not define or limit in any way the manner in which the bore is formed. The tubular adaptor may have a joint end and a free end, and the swivel joint formation may be positioned towards said joint end of the adaptor, and the tubular 25 bore may be positioned towards the free end of the adaptor. The adaptor may include a sleeve formation adjacent to said spigot formation and the sleeve formation may define at least part of the tubular bore. In some forms of the invention the sleeve formation may define the entire tubular bore. 30 The inner tubular member may have an outer surface that is adjacent the bore inner surface, an inner end that is received within the tubular bore formation, and an outer end that is outside of the tubular bore. The inner tubular member may include a 4 conduit fitting end formation towards its free end for attaching the inner sleeve to an adjacent said conduit to which the joint assembly is coupled. The tubular swivel joint member may have a joint end proximate to said one swivel 5 joint formation and a free end remote there from. The tubular swivel joint member may include a conduit formation projecting axially away from said one swivel joint formation towards said free end, which conduit formation may define a conduit fitting end formation at said free end for, in use, attaching the tubular swivel joint member to an associated conduit. 10 In one form of the invention the complementary swivel joint formation on the adaptor may be a spigot formation and the spigot formation may project outwardly proud of the sleeve formation in a radial direction. 15 The spigot formation may define an outwardly facing circumferentially extending frusto-spherical spigot surface that is coaxial with the tubular adaptor for engaging a complementary inward facing socket surface. The frusto-spherical spigot surface of the spigot formation and the bore inner surface 20 may be spaced a short distance apart from each other in a longitudinal direction, e.g. they may be positioned longitudinally adjacent to each other. Instead the frusto-spherical surface of the spigot formation and the bore inner surface may be positioned in broadly the same position along the length of the adaptor. 25 The frusto-spherical surface of the spigot formation may have a spigot point that is closest to the bore inner surface, and the bore inner surface may similarly have a bore point that is closest to the spigot point on the spigot formation. The spigot and bore points of respectively the spigot joint formation and the bore inner surface may be less 30 than 100 mm apart from each other, e.g. less than 50mm apart from each other. The swivel joint formation on said tubular swivel joint member may be a socket formation that defines an inward facing socket surface that complements said outward 5 facing spigot surface on said adaptor. This facilitates pivoting and swiveling movement of the socket formation relative to the spigot formation. The socket formation may be coaxial with the tubular member and may be located at 5 said joint end of said tubular swivel joint member. The inward facing socket surface may be frusto-spherical and may be sized and shaped to slide over said outward facing spigot surface. Instead in another form of the invention, said complementary swivel joint formation on 10 said adaptor may be a socket formation that defines an inwardly facing socket surface for engaging a complementary outward facing spigot surface. The socket formation may be co-axial with the tubular adaptor and may project outwardly proud of the sleeve formation in a radial direction. The socket formation 15 may define an inward facing circumferentially extending frusto-spherical socket surface. The frusto-spherical socket surface and the bore inner surface may be axially spaced a short distance apart from each other, e.g. the frusto-spherical socket surface and 20 the bore inner surface may be positioned adjacent each other in a longitudinal direction. In particular the nearest points on the socket surface and the bore inner surface may be less than 100mm, e.g. less than 50 mm away from each other. In the other form of the invention said one swivel joint formation on said tubular swivel 25 joint member may be a spigot formation that defines an outward facing spigot surface that complements said inward facing socket surface on said adaptor to facilitate pivoting and swiveling movement relative to the socket surface. The spigot formation may be coaxial with the tubular member and may be located at 30 said joint end of the swivel joint member. The spigot formation may have a frusto spherical spigot surface that is sized and shaped to slide over said inward facing frusto-spherical socket surface.

6 In both forms of the invention described above the inner tubular member may include a radially outwardly projecting annular stop that is received within the tubular bore. The adaptor may include an axially outer stop formation towards its free end for 5 limiting travel of the inner tubular member in a direction away from the joint end of the adaptor. For example the axially outer stop formation may be in the form of an annular stop formation that projects from the bore inner surface in a radial inward direction. This enables the adaptor outer stop formation to interfere with axial displacement of the stop formation on the inner tubular member and limit the 10 movement of the inner tubular member in one direction, e.g. in a direction towards the free end of the adaptor. In one form the annular stop formation may be in the form of a discrete annular stop member, e.g. a welding ring, that is permanently mounted on the free end of the 15 adaptor, e.g. by solvent or sonic welding, when the swivel joint assembly is assembled. The adaptor may also include an axially inner stop formation towards its joint end for limiting travel of the inner tubular member in the other direction, e.g. in the direction of 20 said joint end of the adaptor. The axially inner stop formation may be in the form of an annular stop formation that projects in a radial direction inward from the bore inner surface whereby to interfere with the stop formation on the inner tubular member. In one example form of the 25 invention the axially inner stop formation may be in the form of a shoulder extending inward that is integrally formed with the adaptor. The axially inner stop formation may be positioned a distance of less than 100mm in an axial direction from the nearest point of the complementary swivel joint formation 30 on the adaptor, e.g. less than 50 mm. The swivel joint assembly may include a swivel seal mounted on one of the one and complementary swivel joint formations for sealing the complementary spigot and socket surfaces to each other. The swivel seal acts to resist liquid from passing 7 between said spigot and socket surfaces. The swivel seal may include an annular seal member of resilient material, e.g. an O-ring or a chevron seal member. The swivel joint formation on which the seal member is mounted may be the spigot 5 formation having an outward facing frusto-spherical spigot surface, and the spigot surface may define an annular groove within which the seal member is received. The swivel joint assembly may include a sliding seal mounted on one of the bore inner surface (of the adaptor) and the outer surface of the inner tubular member, for sealing 10 the bore inner surface to the outer surface whereby to resist liquid from passing between said inner and outer surfaces of the tubular bore and inner tubular member respectively. The sliding seal may include a chevron seal member, an O-ring seal member or any other form of seal member. 15 The annular stop formation on the inner tubular member may define a radially outer circumferentially extending annular groove, and the seal may include an annular seal member of resilient material that is seated in the annular groove for sealingly engaging and sliding over the bore inner surface of the tubular bore. 20 The swivel joint assembly may include a socket retainer for retaining the socket formation (on the swivel joint member or the adaptor) in its operative position mounted over the spigot formation. The socket retainer may include a collar that concentrically surrounds the spigot 25 formation and is spaced radially outward of the spigot formation, the collar having a retaining shoulder that extends radially inward from one end thereof to a radially inner edge that defines a socket opening which is sized to receive an adjacent portion of the socket formation therein, but to resist the entire socket formation from being withdrawn therethrough. 30 The retaining shoulder of the collar may be sized so as to define a working clearance between the radially inner edge thereof and an outward facing surface of the socket formation so that the socket formation can move relative to the collar, e.g. freely.

8 In the form of the invention where the adaptor has a complementary swivel joint formation that is a spigot formation, the adaptor may also include an annular attachment shoulder for fixing the collar thereto, that projects radially outward from the adaptor, e.g. outward from the sleeve formation of the adaptor. Thus the collar may 5 be fixed to the annular shoulder to effectively mount the collar on the adaptor and thereby fix the spigot and socket formations to each other. In another form of the invention where the tubular swivel joint member has a swivel joint formation that is a spigot or socket formation, the tubular swivel joint member 10 may include an annular attachment shoulder that projects radially outward from the swivel joint member. The collar may be fixed to the annular shoulder to effectively mount the collar on the spigot formation. The adaptor and the tubular joint member may be of unitary structure and may be 15 formed from a thermoforming or thermosetting plastics material in a moulding operation. Conveniently the adaptor including the spigot formation, the tubular bore, the axially inner stop formation, the recess for the seal, and the annular attachment shoulder 20 may be integrally formed by of plastics material by injection moulding in a single injection moulding operation. Similarly the swivel joint member with the spigot or socket formation, and the pipe fitting end formation, may conveniently be integrally formed of plastics material by injection moulding in another single injection moulding operation. The inner tubular member with the annular stop formation and the recess 25 therein for receiving the seal member may also be conveniently integrally formed of plastics material by injection moulding in a single injection moulding operation. Conveniently the adaptor, tubular joint member and the inner tubular member may be formed from a synthetic plastics material. It will be appreciated that these parts can 30 be formed from a thermoforming or thermosetting plastics material in a said injection moulding operation. According to another aspect of the invention there is provided an adaptor for coupling to tubular swivel joint member having one swivel joint formation, the adaptor including: 9 a tubular adaptor body including a complementary swivel joint formation for engaging said one swivel joint formation in a swivel socket fashion, and a telescopic displacement formation for operative coupling to a displaceable tubular member such 5 that the displaceable tubular member is in flow communication therewith and is telescopically displaceable relative to the tubular adaptor whereby to render the joint assembly axially expansible as well as capable of a swivelling action. The telescopic displacement formation may include a tubular bore having a bore inner 10 surface. The complementary swivel joint formation on the adaptor may be one of a spigot or socket formation for engaging a complementary swivel joint formation on the tubular swivel joint member that is the other of a spigot or socket formation. 15 The tubular adaptor may have a joint end and a free end, and the swivel joint formation may be positioned towards said joint end of the adaptor, and the tubular bore may be positioned towards the free end of the adaptor. 20 The adaptor may include a sleeve formation adjacent to said spigot formation and the sleeve formation may define at least part of the tubular bore. In some forms of the invention the sleeve formation may define the entire tubular bore. In one form of the invention the swivel joint formation on the adaptor may be a spigot 25 formation and the spigot formation may project outwardly proud of the sleeve formation in a radial direction. The spigot formation may define an outwardly facing circumferentially extending frusto-spherical spigot surface that is coaxial with the tubular adaptor for engaging a 30 complementary inward facing socket surface. The frusto-spherical spigot surface of the spigot formation and the bore inner surface may be spaced a short distance apart from each other in a longitudinal direction, e.g. they may be positioned longitudinally adjacent to each other.

10 Instead the frusto-spherical surface of the spigot formation and the bore inner surface may be positioned in broadly the same position along the length of the adaptor. 5 The adaptor may include a swivel seal mounted on the spigot surface of the spigot formation for acting to resist liquid from passing between said spigot surface and an adjacent socket surface in use. Instead in another form of the invention, said complementary swivel joint formation on 10 said adaptor may be a socket formation that defines an inwardly facing socket surface for engaging a complementary outward facing spigot surface. The socket formation may be coaxial with the tubular adaptor and may project outwardly proud of the sleeve formation in a radial direction. The socket formation 15 may define an inward facing circumferentially extending frusto-spherical socket surface. The frusto-spherical socket surface and the bore inner surface may be axially spaced a short distance apart from each other, e.g. the frusto-spherical socket surface and 20 the bore inner surface may be positioned adjacent each other in a longitudinal direction. In both forms of the invention described above the adaptor may include an axially outer stop formation towards its free end for limiting travel of the inner tubular member 25 in a direction away from the joint end of the adaptor. For example the axially outer stop formation may be in the form of an annular stop formation that projects from the bore inner surface in a radial inward direction. This enables the adaptor outer stop formation to interfere with axial displacement of the stop formation on the inner tubular member and limit the movement of the inner tubular member in one direction, e.g. in a 30 direction towards the free end of the adaptor. In one form the annular stop formation may be in the form of a discrete annular stop member, e.g. a welding ring, that is permanently mounted on the free end of the 11 adaptor, e.g. by solvent or sonic welding, when the swivel joint assembly is assembled. The adaptor may also include an axially inner stop formation towards its joint end for 5 limiting travel of the inner tubular member in the other direction, e.g. in the direction of said joint end of the adaptor. The axially inner stop formation may be in the form of an annular stop formation that projects in a radial direction inward from the bore inner surface whereby to interfere 10 with the stop formation on the inner tubular member. In one example form of the invention the axially inner stop formation may be in the form of a shoulder extending inward that is integrally formed with the adaptor. The axially inner stop formation may be positioned a distance of less than 100mm in 15 an axial direction from the nearest point of the complementary swivel joint formation on the adaptor, e.g. less than 50 mm. According to yet another aspect of the invention there is provided a pipeline installation which includes: 20 a swivel joint assembly as defined in the preceding aspect of the invention having one and opposed joint ends; one conduit operatively connected to one joint end of the swivel joint assembly; 25 and another conduit operatively connected to the opposed joint end of the swivel joint assembly, 30 whereby the swivel joint assembly is capable of swivelling and is axially expansible to relieve stresses that build up in the one and other conduits. The swivel joint may include any one or more of the optional features of the swivel joint assembly defined in the preceding aspect of the invention.

12 The one and other conduits may be circular pipes and the pipes may be made of plastics material, e.g. PVC (polyvinylchloride), SBS (styrenebutadienestyrene), ABS (acrylonitrilebutadienestyrene), or ASA (acrylostyreneacrylate). Each pipe may have 5 a diameter in the range of 60 to 160mm. In one form the pipes may have a nominal diameter of 95 to 105mm. In another form the drain pipe may have a nominal diameter of 145mm to 155mm. The pipeline installation may be a subterranean installation that is received within the 10 ground. In one form the pipeline installation may be a wastewater pipeline for draining wastewater from a structure to a waste water main spaced away from the structure, e.g. a sewerage pipeline installation. The installation comprising the joint assembly and the one and other conduits may 15 have an axial length that is less than 3 metre, in some cases less than 2 metres, e.g. 1.0m to 1.5m. The tubular swivel joint assembly may include any one or more of the optional features of the tubular swivel joint assembly defined in the first aspect of the invention 20 above. In particular the tubular swivel joint member and the inner tubular member may include pipe fitting end formations that complement the adjacent pipe ends of the one and other conduits to which they are coupled. 25 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A swivel joint for coupling two conduits and a pipeline installation in accordance with the invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe in detail several example embodiments of the invention with 30 reference to accompanying diagrammatic drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the 13 generality of the preceding broad description. In the accompanying diagrammatic drawings: Figure 1 is a three-dimensional view of an axially extendible swivel joint assembly in 5 accordance with one embodiment of the invention, viewed from one end; Figure 2 is a three-dimensional view of the swivel joint assembly of Figure 1 viewed from the other end; 10 Figure 3 is an exploded three-dimensional view of the swivel joint assembly of Figure 1, with seal members omitted for clarity; Figure 4 is a sectional front view of the swivel joint assembly of Figure 1 showing the joint assembly in a linearly extending orientation; 15 Figure 5 is a sectional front view of the swivel joint assembly of Figure 1 showing the joint assembly in a pivoting orientation; Figure 6 is a schematic sectional view of a pipeline installation including the swivel 20 joint assembly of Figure 1 received within the ground; Figure 7 is a sectional side view of a swivel joint assembly in accordance with another embodiment of the invention showing the joint assembly in a linearly extending orientation; and 25 Figure 8 is a sectional side view of a swivel joint assembly in accordance with yet another embodiment of the invention showing the joint assembly in a linearly extending orientation. 30 In Figures 1 to 5 reference numeral 10 generally refers to an axially extendible swivel joint assembly, in accordance with the invention. The swivel joint assembly 10 comprises broadly a tubular swivel joint member 12 having one swivel joint formation that is a socket formation 14 and a tubular adaptor 14 16 comprising a complementary swivel joint formation that is a spigot formation 18 and a sleeve formation 20. The adaptor 16 defines a tubular bore 22 having a bore inner surface 24. The assembly 10 also includes a displaceable inner tubular member 26 that is telescopically displaceable within the bore 22 whereby to render the joint 5 assembly 10 axially expansible as well as capable of a swivelling action. The inner tubular member 26 has an inner end 28 that is received within the sleeve formation 20 and an outer end 30 that is positioned outside of the sleeve formation 20. 10 The tubular swivel joint member 12 has a joint end 34 that is proximate to said socket formation 14 and a free end 36 remote there from. The tubular swivel joint member 12 also includes a conduit formation 38 projecting axially away from socket formation 14 towards said free end 36. The conduit formation 38 defines a conduit fitting end formation at the end 36 for attaching the tubular swivel joint member 12 to an 15 associated conduit, e.g. forming part of the pipeline to which it is coupled. The tubular adaptor 16 has a joint end 40 towards which the spigot formation 18 is positioned and a free end 42 towards which the sleeve formation 20 is positioned. The spigot formation 18 projects outwardly proud of the sleeve formation 20 and 20 defines an outwardly facing spigot surface 44 that is frusto-spherical and circumferentially extending and is coaxial with the tubular adaptor 16. The frusto-spherical surface 44 of the spigot formation 18 and the bore inner surface 24 are positioned spaced only a short distance apart from each other in a longitudinal 25 direction. The frusto-spherical surface 44 of the spigot formation 18 has a spigot point, indicated by reference numeral 45, that is closest to the bore inner surface 24, and the bore inner surface similarly has a bore point 46 that is closest to the frusto-spherical 30 surface of the spigot formation 18. In Figures 1 to 5 the spigot and bore points 45, 46 of respectively the spigot formation 18 and the bore inner surface 24 are less than 50mm apart from each other, e.g. about 15 to 25mm, such as 20mm, apart from each other.

15 The tubular bore 22 has an inner surface that has a longitudinal length of at least 70mm, e.g. a length in the range of 80-100mm, which length is shown in Figure 4 by reference numeral 30. The bore 22 permits a longitudinal expansion or contraction of the joint of at least 50mm, e.g. an expansion or contraction of 65mm to 85mm, such 5 as 75 mm. The socket formation 14 has an inward facing frusto-spherical socket surface 48 that complements said outward facing spigot surface 44 on said adaptor 16 and is sized and shaped to slide over said outward facing spigot surface 44. The socket formation 10 14 is coaxial with the tubular swivel joint member 12. The inner tubular member 26 also includes a conduit fitting end formation at its free end 30 for attaching the member 26 to an adjacent conduit in a pipeline installation. 15 The inner tubular member 26 also includes a radially outwardly projecting annular stop 52 that is received within the tubular bore 22 formed integrally therewith. The adaptor 16 includes an axially outer stop formation 54 at its free end 42 in the form of a radially inward projecting stop formation. In the illustrated embodiment the 20 outer stop formation 54 is in the form a ring that is retrofitted by 'plastic welding' to the free end 42 of the adaptor 16 after the inner tubular member 26 is installed into the adaptor 16, when assembling the swivel joint assembly 10. The adaptor 16 also includes an axially inner stop formation 56 at its joint end for 25 stopping the annular stop 52 on the inner tubular member 26 and thereby limiting its movement in the other direction, e.g. towards the joint end of the adaptor 16. In the illustration embodiment the inner stop formation 56 is in the form of a radially inwardly extending shoulder that is formed integrally with the adaptor 16. 30 The swivel joint assembly 10 includes a swivel seal indicated generally by numeral 60 mounted on the spigot formation 18 on the adaptor 16 for sealing the outward facing frusto-spherical spigot surface 44 to the inward facing frusto-spherical socket surface 48 on the socket formation 14.

16 The spigot surface 44 defines an annular groove 62 that extends circumferentially around the spigot formation 18 and the swivel seal 60 includes a seal member in the form of an annular ring of resilient material that is received within the annular groove 62. 5 The swivel joint assembly 10 also includes a sliding seal indicated generally by numeral 64 mounted on the inner tubular member 26 for sealing against the inner surface 24 of the tubular bore 22. The annular stop formation 52 on the inner tubular member 26 defines an annular groove 66 and the sliding seal comprises a resilient 10 seal member that is received within the annular groove 66. The seal member engages the inner surface 24 of the bore 22 and seals the inner tubular member 26 to this bore inner surface 24. In another embodiment that has not been illustrated the swivel seal, and optionally 15 also the sliding seal, is in the form of a chevron seal. The shape and configuration of the chevron seal and the groove in the spigot formation 18 for receiving the chevron seal are illustrated in Figs 7 and 8. The swivel joint assembly 10 also includes a socket retainer 70 that retains the swivel 20 joint member 12 including the socket formation 14 mounted in its operative position on the adaptor 16. The retainer 70 includes a collar having a substantially cylindrical side wall 72 that concentrically surrounds the socket formation 14 and two opposed ends. The collar has a retaining shoulder 74 projecting in from one end of the side wall 72 25 defining a socket opening through which an adjacent region of the socket formation 16 is received. The socket opening is sized to resist the entire socket formation 16, and particularly the enlarged joint end 34 thereof, from being withdrawn through the socket opening and thereby acts to retain it on the spigot formation 18 and fix it thereto. 30 In addition the socket opening is sized to define a working clearance between the radial inner edge of the shoulder 72 and the adjacent region of the outward facing surface of the socket formation 16.

17 The assembly 10 includes an annular attachment shoulder 76 on the adaptor 16 projecting radially outward away from the sleeve formation 20. The other end of the side wall 72 of the collar 70 is permanently mounted to the annular attachment shoulder 76, thereby to fix it to the adaptor 16 and also the spigot formation 18. 5 Conveniently the other end of the side wall 72 is permanently fixed to the attachment shoulder 76 by sonic or solvent welding or the like thereby to permanently attach the various members to each other to form an assembled joint 10 as a vendible product. The adaptor 16 including the spigot formation, the tubular bore, the axially inner stop 10 formation, the recess for the seal, and the annular attachment shoulder is conveniently integrally formed of plastics material by injection moulding in a single injection moulding operation. Similarly the tubular joint member with the socket formation, and the pipe fitting end formation, is conveniently integrally formed by of plastics material by injection moulding in another single injection moulding operation. 15 The inner tubular member with the annular stop formation and the recess therein for receiving the seal member, is also integrally formed by of plastics material by injection moulding in a single injection moulding operation. Conveniently the adaptor and the other parts such as the swivel fitting, the collar, and 20 the inner sleeve 20 are formed from a synthetic plastics material. These parts can for example be formed from compounds that include one or more engineering plastics materials such as PVC (Polyvinylchloride), or ABS (Acrylonitrile Butadiene Styrene), SBS (Styrene Butadiene Styrene) or ASA (Acrylonitrile Styrene Acrylate). 25 In use the swivel joint assembly 10 forms part of a drainage pipe line installation 100 for draining waste water at a domestic setting. In one form the pipe fitting end formations on the inner tubular member 26 and the tubular swivel joint member 12 have a nominal diameter of 95mm to 105mm which 30 corresponds to a standard and widely used pipe size. In another form the pipe fitting end formations on the inner tubular member 26 and the tubular swivel joint member 12 have a nominal diameter of 145mm to 155mm which corresponds to a standard and widely used pipe size. The conduit fitting end formations on the ends 42 and 62 18 of the inner tubular member 26 and the swivel joint member 12 are sized and shaped for fitment to these conventional size pipes. As shown in the drawings the nominal diameter of the tubular swivel joint member 12 5 and the inner tubular member 26 is comparable to those of their pipe fitting end formations. The diameter of the sleeve formation 20 on the adaptor 16 is slightly larger than the diameter of the tubular swivel joint member 12 and the inner tubular member 26 whereby to enable it to receive the inner tubular member 26. 10 In one application the pipeline installation 100 includes a transverse intermediate pipe section 102 extending from a concrete slab 103, e.g. of a dwelling structure, to a main pipe 104 leading to a sewerage main or the like (not shown). The pipe section 102 may only have a length of 1-2m depending on the space along the side of a house and the size of the block of land on which the dwelling is built. The intermediate pipe 15 section 102 is subjected to forces in response to movements in the slab 103 and other ground movement. As the main pipe 104 is coupled to the sewerage main and is effectively fixed in position, the intermediate pipe section 102 is not capable of moving in sympathy with the movement in the slab 103, and has to accommodate for this movement to relieve stresses on the pipe 102. 20 When this occurs the spigot and socket formations of the joint 10 can pivot and rotate relative to each other to relieve stresses on the pipe forming the intermediate pipe section 102. Such movements result in a variation in the axial length of the pipe section 102. The inner tubular member 26 of the joint 10 can adjust slidably with 25 respect to the adaptor 16 to accommodate these differences in length. Fig 7 shows a swivel joint assembly in accordance with another embodiment of the invention. The swivel joint assembly in Fig 7 is similar to that described above with reference to Figs 1 to 5 and accordingly the same reference numerals will be used to 30 refer to the same components unless otherwise illustrated. Further the following description will focus on the differences between this embodiment and the earlier embodiment in Figs 1 to 5.

19 In Fig 7 the axially inner stop formation 56 on the adaptor 16 is positioned adjacent the joint end 40 of the adaptor 16 and it is positioned largely forward of the spigot formation 18. 5 The axially outer stop formation 54 is positioned at the free end 42 of the adaptor 16 in the same way as in the embodiment shown in Figs 1 to 5. Overall the adaptor 16 in Fig 7 has a shorter axial length than that shown in the Fig 1 embodiment. However the spacing between the axially inner and outer stop formations 56, 54 is the same as in the Fig 1 embodiment and thus the permissible range of travel of the stop 52 on the 10 inner tubular member 26 is the same as in the Fig 1 embodiment. Thus the extent to which the swivel joint assembly 10 can cater for axial expansion or contraction is the same as for the Fig 1 embodiment. In summary in the Fig 7 embodiment the axially inner and outer stop formations 45, 56 15 are moved closer to the spigot formation 18. The axially inner stop formation 56 is located on the other side of the spigot formation 18 to that shown in the Fig 1 embodiment. This enables the swivel valve assembly 10 to have a more compact construction particularly in a longitudinal direction. 20 In addition the swivel seal in the Fig 7 embodiment is in the form of a chevron seal. The annular groove 62 defined in the spigot formation 18 has a different shape to the groove shown in Fig 4 whereby to render it suitable for receiving the chevron seal. Specifically the annular groove has a greater axial extent and is generally larger than the groove 62 shown in Fig 4. As chevron seals are known in the art they will not be 25 described in greater detail in this description. The embodiment shown in Figs 1 to 4 can also be fitted with a chevron seal like that shown in Fig 7 with corresponding changes in the groove 62 defined in the spigot surface 18. A chevron seal is well suited to sealing at higher pressures than an O-ring 30 seal and will typically be used where this is required. In use the swivel joint assembly functions in the same way as the joint assembly in Fig 1.

20 Fig 8 shows a swivel joint assembly in accordance with another embodiment of the invention. The swivel joint assembly in Fig 8 is similar to that described above with reference to Figs 1 to 5 and accordingly the same reference numerals will be used to refer to the same components unless otherwise illustrated. 5 Further the following description will focus on the differences between this embodiment and the earlier embodiment in Figs 1 to 5. In Fig 8 the swivel joint formation on the tubular joint member 12 is a spigot formation 10 80 and the swivel joint formation on the adaptor 16 is a socket formation 82. Thus the positions on the spigot and socket formations 80, 82 are reversed in Fig 8 when compared with the Fig 1 embodiment. The adaptor 16 in addition to said socket formation 82 also defines a tubular bore 84 15 having a bore inner surface 85. The adaptor 16 also includes a sleeve formation 86 adjacent to the socket formation 82 towards the free end 42 thereof. In this embodiment the tubular bore 84 is wholly received within the sleeve formation 86 of the adaptor 16 as shown in the drawings. It terminates short of the start of the socket formation 82 and therefore could be more appropriately described as being adjacent 20 to the socket formation 82 rather than being received within the socket formation 82. In this respect it is not as axially compact as the embodiment illustrated in Fig 7. The axially outer formation 88 is formed by a discrete annular stop member or welding ring that is welded onto the free end of the member 12. The axially inner stop 25 formation 89 terminates short of the socket formation 82, e.g. closely adjacent to the socket formation 82, and is formed by a shoulder extending in a radial inward direction that conveniently is formed integrally with the member 12. In addition the swivel seal in the Fig 8 embodiment is in the form of a chevron seal. 30 The annular groove 62 defined in the spigot formation 18 has a different shape to the groove shown in Fig 4 so that it can snugly receive the chevron seal. In use the swivel joint assembly 10 functions in the same way and performs the same role as the swivel joint assembly 10 in Fig 1.

21 An advantage of the swivel joint assembly described above in Figs 1 to 8 with reference to the drawings is that it comprises a single assembled and preformed joint assembly that includes both an ability to swivel and an ability to expand or contract in 5 length. It does this by means of an adaptor which is positioned intermediate the tubular swivel joint member and the inner tubular member. This enables the associated pipeline to which the swivel joint assembly is coupled to adjust in orientation and also in length to accommodate movement and consequent stresses in the pipeline. 10 Another advantage of the joint assembly in Figures 1 to 5 is that a swivelling capability and an ability to adjust lengthwise by telescopic movement is provided within a short axial distance. Not only are both capabilities provided in the same joint assembly but the joint is also compact. Further the spigot and socket formations are closely spaced 15 from the sleeve formation which effects the telescoping movement. The swivel joint within the assembly has a swivel joint axis about which the spigot and socket formations can pivot and swivel relative to each other. Further the expansion joint has an innermost position defined by the axially inner stop formation. 20 In some applications the pipeline extending between a slab and a main drainage line within which a swivelling and pivoting capability is required to be provided is of a very short and compact length, e.g. of 1 to 2 m. Therefore there is a very short axial length of pipe to which the pipe joints can be coupled to confer the requisite ability to move. By providing a single compact joint assembly conferring both swivelling 25 movement and axial expansibility this ability can be obtained in a pipe section of very short length. A typical swivel joint assembly in accordance with this invention might have an axial length of 200-400mm, e.g. about 280mm, in a retracted condition, and an axial length of 300-500mm, e.g. about 355 mm, in an extended condition. 30 Furthermore in the construction shown in Fig 7 the tubular bore can be received within the spigot formation further compressing the axial length of the joint assembly and overlapping the joint axis of the swivel joint and the range of travel of the inner tubular member. This construction achieves a particular localization of the swivelling and telescoping functions.

22 Applicant believes that working advantage is conferred by the swivel joint axis and the innermost position being as close to each other as possible. Without being bound by theory Applicant believes that the external frictional resistance to an adjusting 5 movement of a pipe to relieve stresses is less when the swivel and expansion joint functions are received within the same housing. Consequently the joint assembly and associated pipeline can often adjust more easily and thereby the stresses imposed on the associated pipes during this adjustment process are lower. 10 A yet further advantage of the joint assemblies described above with reference to Figs 1, 7 and 8 is that the adaptor with its swivel joint formation can also be integrally formed by means of an injection moulding operation. Similarly the tubular swivel joint member with its different swivel joint formation can be integrally formed by means of an injection moulding operation as can the inner tubular member. Thus the 15 components can be moulded with a high tolerance and the swivel joint assembly can be manufactured cost effectively It will of course be realized that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as 20 would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set forth.

Claims

1. A swivel joint assembly for coupling two tubular conduits to each other in flow communication with each other, which includes: 5 a tubular swivel joint member having one swivel joint formation; a tubular adaptor including a complementary swivel joint formation that is complementary to said one swivel joint formation; and 10 a displaceable tubular member that is operatively coupled to said tubular adaptor such that it is in flow communication therewith, wherein the displaceable tubular member is telescopically displaceable relative to the tubular adaptor whereby to render the joint assembly axially expansible as well as capable of a swivelling 15 action.

2. A swivel joint assembly as claimed in claim 1, wherein the one swivel joint formation on the tubular swivel joint member is one of a spigot or socket formation and the complementary swivel joint formation on the adaptor is the other of a spigot or 20 socket formation.

3. A swivel joint assembly as claimed in claim 2, wherein the tubular adaptor includes a tubular bore having a bore inner surface, and the displaceable tubular member is an inner tubular member that is received within the tubular bore and is 25 telescopically displaceable within the tubular bore.

4. A swivel joint assembly as claimed in claim 3, wherein the tubular adaptor has a joint end and a free end, and the swivel joint formation is positioned towards said joint end of the adaptor, and the tubular bore is positioned towards the free end of the 30 adaptor.

5. A swivel joint assembly as claimed in claim 3 or claim 4, wherein the adaptor includes a sleeve formation adjacent to said complementary swivel joint formation, and the sleeve formation defines at least part of the tubular bore. 24

6. A swivel joint assembly as claimed in any one of claims 3 to 5, wherein the inner tubular member has an outer surface that is adjacent the bore inner surface, and an inner end that is received within the tubular bore and an outer end that is outside of 5 the tubular bore.

7. A swivel joint assembly as claimed in claim 6, wherein the tubular swivel joint member has a joint end proximate to said one swivel joint formation and a free end remote there from, and a conduit formation projecting axially away from said one 10 swivel joint formation towards said free end.

8. A swivel joint assembly as claimed in claim 7, wherein the complementary swivel joint formation on the adaptor is a spigot formation and the spigot formation projects outwardly proud of the sleeve formation in a radial direction. 15

9. A swivel joint assembly as claimed in claim 8, wherein the spigot formation defines an outwardly facing circumferentially extending frusto-spherical spigot surface that is coaxial with the tubular adaptor for engaging a complementary inward facing socket surface, and wherein the frusto-spherical spigot surface of the spigot formation 20 and the bore inner surface are spaced a short distance apart from each other in a longitudinal direction.

10. A swivel joint assembly as claimed in claim 9, wherein the swivel joint formation on said tubular swivel joint member is a socket formation that defines an 25 inward facing socket surface that complements said outward facing spigot surface on said adaptor.

11. A swivel joint assembly as claimed in claim 10, wherein the socket formation is coaxial with the tubular member and is located at said joint end of said tubular swivel 30 joint member, and wherein the inward facing socket surface is frusto-spherical and is sized and shaped to slide over said complementary outward facing spigot surface. 25

12. A swivel joint assembly as claimed in claim 7, wherein said complementary swivel joint formation on said adaptor is a socket formation that defines an inwardly facing socket surface for engaging a complementary outward facing spigot surface. 5

13. A swivel joint assembly as claimed in claim 12, wherein the socket formation is coaxial with the tubular adaptor and projects outwardly proud of the sleeve formation in a radial direction, and defines a frusto-spherical socket surface, and wherein the socket surface and the bore inner surface are axially spaced a short distance apart from each other. 10

14. A swivel joint assembly as claimed in claim 12 or claim 13, wherein said one swivel joint formation on said tubular swivel joint member is a spigot formation that defines an outward facing spigot surface that complements said inward facing socket surface on said adaptor to facilitate pivoting and swivelling movement relative to the 15 socket surface.

15. A swivel joint assembly as claimed in claim 14, wherein the spigot formation is coaxial with the tubular member and is located at said joint end of the swivel joint member, and wherein the spigot formation has a frusto-spherical spigot surface that is 20 sized and shaped to slide over said inward facing frusto-spherical socket surface.

16. A swivel joint assembly as claimed in any one of claims 7 to 15, wherein the inner tubular member includes a radially outwardly projecting annular stop that is received within the tubular bore. 25

17. A swivel joint assembly as claimed in claim 16, wherein the adaptor includes an axially outer stop formation towards its free end for limiting travel of the inner tubular member in a direction away from the joint end of the adaptor, and wherein the adaptor also includes an axially inner stop formation towards its joint end for limiting travel of 30 the inner tubular member in the other direction.

18. A swivel joint assembly as claimed in claim 17, wherein the swivel joint assembly includes a swivel seal mounted on one of the one and complementary swivel joint formations for sealing the complementary spigot and socket surfaces to 26 each other.

19. A swivel joint assembly as claimed in claim 18, wherein the swivel joint assembly includes a sliding seal mounted on one of the bore inner surface and the 5 outer surface of the inner tubular member, for sealing the bore inner surface to the outer surface whereby to resist liquid from passing between said inner and outer surfaces of the tubular bore and inner tubular member respectively.

20. A swivel joint assembly as claimed in any one of claims 2 to 19, wherein the 10 swivel joint assembly includes a socket retainer for retaining the socket formation (on the swivel joint member or the adaptor) in its operative position mounted over the spigot formation.

21. A swivel joint assembly as claimed in claim 20, wherein the socket retainer 15 includes a collar that concentrically surrounds the spigot formation and is spaced radially outward of the spigot formation, the collar having a retaining shoulder that extends radially inward from one end thereof to a radially inner edge that defines a socket opening which is sized to receive an adjacent portion of the socket formation therein but to resist the entire socket formation from being withdrawn therethrough. 20

22. A swivel joint assembly as claimed in claim 21 when dependent on claim 8, wherein the adaptor has a complementary swivel joint formation that is a spigot formation, and wherein the adaptor also includes an annular attachment shoulder that projects radially outward from the adaptor, whereby the collar can be fixed to the 25 annular shoulder to effectively mount the collar on the adaptor.

23. A swivel joint assembly as claimed in claim 23 when dependent on claim 12, wherein the tubular swivel joint member has a socket formation, and wherein the tubular swivel joint member includes an annular attachment shoulder that projects 30 radially outward from the swivel joint member, whereby the collar can be fixed to the annular shoulder to effectively mount the collar on the swivel joint member. 27

24. A pipeline installation for conveying liquid from one point to another which includes: a swivel joint assembly as defined in any one of claims 1 to 23; one conduit operatively connected to one end of the swivel joint assembly; and 5 another conduit operatively connected to the other end of the swivel joint assembly, whereby the swivel joint assembly is capable of swivelling and is axially expansible to relieve stresses that build up in the one and other conduits. 10

25. A pipeline installation according to claim 24, wherein said one and other conduits are circular pipes that are made of plastics material, selected from the group consisting of PVC (polyvinylchloride), SBS (styrenebutadienestyrene), and ABS (acrylonitrilebutadienestyrene) and ASA (acrylostyreneacrylate). 15

26. A pipeline installation according to claim 25, wherein the one and other conduits and the swivel joint assembly are received within the ground, and the conduits convey wastewater away from a structure.