FIELD OF INVENTION

This invention relates to a collar for use in a pipe system and a method for the joining of pipes The invention is particularly useful for large diameter concrete pipes such as those used for sewerage and the handling and drainage of storm water

BACKGROUND ART The joining of large diameter concrete pipes for sewerage and storm water drainage is associated with various problems. In particular, it is difficult to maintain joint integrity and to effect a water resistant seal where pipes are flush jointed

Common methods of joining concrete pipes presently in use involves spigot and socket rubber ring joints for all storm water pipes up to 600 mm diameter. Larger diameter pipes are generally flush jointed _.

Flush joining of pipes involves the laying of pipe segments by abutting them end to end and providing a circumferential seal around each individual join Flush joins are either of the internal or external flush type in which the gap in the join is filled with mortar rendering and sometimes with the addition of an external band that slows the ingress of water and prevents most fines from infiltrating the joint but does not resist the egress of water

Any misalignment due to bad laying practice, ground movement or other causes of misalignment commonly results in the failure of the function of the joint.

Water resistance of joints in pipes is desirable from several points of view One problem is associated with the leakage of underground water into sewerage and storm water drainage systems which results in a reduction of the effectiveness of the sewerage and waste water plants respectively. Furthermore, ingress of bedding or soil material from around large pipes may result in ground collapse such as under roads and pavements

Leakage of sewerage or waste water into the surrounding area due to a _j oint failure is also undesirable from a health and env _i ronmental perspective Leaking of water and highly nutr ⁱ ent matter encourages opportunistic plant root growth which often results ⁱ n extensive and expensive blockages of the system

In some cases _, leakage of liquid into the surrounding soil espec _i ally where high internal pressure is involved may result ⁱ n underm _i n _i ng building foundations and/or the cracking of pavements due to the hydroscopic swelling of clay soils

Flush _j oint pipelines have for many years, been constructed by lay _i ng sp _i got and socket Flush Joint" pipes and rendering the result ⁱ ng _j oint internally or externally with sand and cement mortar

In recent years an elastromeπc wrapping or ^" Sand Band ^" has been appl _i ed to attempt to alleviate the joint failure occurring as a result of d _i fferent _i al movement of the pipes in the pipeline and the subsequent d _i splacement and disintegration of the relatively brittle cement render ⁱ ng

Both of the aforementioned methods of jointing are cons _i dered to be inefficient liable to error in application, and make verification of _j oint integrity difficult

There is also a requirement for the joining of pipes to structures such as manhole or gutter box facilities

In these applications the usual method employed is to construct the manhole or gutter box around the end of the p ⁱ pe

S _i m _i lar problems as previously mentioned with the flush _j o _i n _i ng of pipes are also encountered e g poor laying pract ⁱ ce and ground movement which often results in leakage and the cracking of the jo ⁱ nts and/or the pipes themselves

OBJECT OF THE INVENTION

It _i s an ob _j ect of the invention to overcome or alleviate at least one of the problems associated with prior art joining of a pipe or p ⁱ pes to a collar

DISCLOSURE OF THE INVENTION

According to one aspect of the invention there is provided a collar for engagement with one or more pipes, said collar comprising an intermediate internally extending circumferential projection dividing said collar into two internal portions wherein at least one of said portions has a 5 compression section adjacent to said internally extending circumferential projection for the compressive engagement of a pipe and a lead section for guiding said pipe into said compression section

Preferably the internally extending circumferential projection is a flexible hinge adapted to allow relative movement between said two i () portions

Suitably the flexible hinge is integrally formed in the collar Preferably the flexible hinge forms a channel in an outer surface of the collar

There may be a rubberised ring in the channel i ') Suitably said compression section is divided into at least two regions having internal surfaces of different gradients with respect to a longitudinal axis of a collar

Preferably both the gradients slope to continuously decrease the internal diameter of said compression section as it extends from the 0 lead section towards the inwardly extending circumferential projection

The said gradients may suitably slope in opposite directions Suitably the said regions meet at a regulation point having an internal diameter which is less than the minimum internal diameter of either one of the said regions ") There may be an outwardly tapering lead section adapted to flex relative to the compression section Suitably there may be a weakened portion between the lead section and the compression section to allow flexing therebetween

Preferably one of said two portions is an integral length of 0 conduit

Suitably the collar is integrally formed from a resilient material

There may be an elastomeric lining on the inner surface of the compression section.

Preferably, there are a plurality of radial strengthening webs along a length of an external surface of said collar Suitably the webs extend between an outer surface of an edge portion of a lead section to an outer surface of said compression section

According to another aspect of the invention there is provided a method for joining pipes including the steps of ^' applying a sealant adjacent an end of a pipe; sliding said pipe into a fπctional grip section of a collar until said pipe abuts an internally extending circumferential projection of said collar. applying a sealant adjacent an end of another pipe; and sliding said another pipe into another compression section of said collar until said another pipe abuts the internally extending circumferential projection.

Preferably the method may be further characterised by the internally extending circumferential projection being a flexible hinge adapted to allow relative movement between the compression sections.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be readily understood and put into practical effect, reference will now be made to preferred embodiments in which Fig 1 is a cross sectional profile of a collar according to a first embodiment of the invention,

Fig 2 is a cross sectional profile of a collar according to a second embodiment of the invention,

Fig 3 is a cross sectional profile of a collar according to a third embodiment of the invention,

Fig 4 shows a cross section of the collar of FIG 1 joining two flush jointed pipes

Fig 5 is a perspective view of collar according to a fourth embodiment of the invention adapted for the joining of flush jointed pipes to gutter boxes or manholes, and

Fig 6 shows the collar of Fig 5 joined to a gutter box. 5 DETAILED DESCRIPTION OF THE DRAWINGS

In Fig 1 there is shown a cross sectional profile of an annular collar 1 having an integral flexible hinge 2 forming a channel 5 in an outer surface of collar 1 Collar 1 is formed from any suitable resilient material and flexible hinge 2 forms an intermediate internally extending portion in i 0 collar 1 and divides collar 1 into two portions 4 Each one of portions 4 has a compression section 3 and an outwardly tapering lead section 6 for guiding a pipe into compression section 3 On the internal surface of compression section 3 there is an elastomeπc lining 3c which is deformable to provide a seal between an inserted pipe and compression l 5 section 3

Section 3 is divided into a frictioπal grip region 3a and a compression region 3b having internal surfaces of different gradients. The gradient X1 of the friction grip region 3a as determined from a longitudinal axis 6a of collar 1 is steeper than the gradient Y1 of 0 compression region 3b This ensures a progressively increasing radial force around a pipe (not shown) as it is inserted into the collar 1

On an external surface of collar 1 there is a plurality of radial strengthening webs 4a each of which extends along a length of collar 1 from an edge portion of a respective lead section 6 to an outer surface of 5 a respective compression section 3.

It will be apparent to a skilled addressee that the compression section 3 may be divided into a greater number of regions in addition to regions 3a and 3b. For example the compression section 3 may divide into numerous regions which effectively result in a curved section 0 between the lead section 6 and the flexible hinge 2.

In Fig 2 there is shown a cross sectional profile of an annular collar 7 having an integral flexible hinge 8, forming a cannel 11 in an

outer surface of collar 7 Flexible hinge 8 forms an intermediate internally extending portion in collar 7 and divides collar 7 into two portions 10 Each one of portions 10 has a compression section 9 and a lead section 12 for guiding a pipe into compression section 9 Further, on an outer 5 surface of collar 7 there are radial strengthening ribs 10a

Section 9 is divided into a fπctional grip region 9a and a compression region 9b having internal surfaces of different gradients

The gradient X ₂ relative to longitudinal axis 7a of the fπctional grip region 9a slopes upwardly from the base of the flexible hinge 8 to i 0 form a crest or regulation point 1 3 with the compression region 9b The gradient Y relative to longitudinal axis 7a of the region 9b slopes in the opposite direction to the gradient of the region 9a Lead section 12 is adjacent region 9b to facilitate the location and insertion of a pipe

As the internal diameter of the regulation point 13 is less than i 5 the minimum internal diameter of either regions 9a or 9b, the insertion of a pipe causes region 9a to flatten out to firmly engage the pipe with an increased radial force

In Fig 3 there is shown a cross sectional profile of an annular collar 13 having a flexible hinge 14 forming a channel 17 in an outer 20 surface of collar 13 Flexible hinge 14 forms an intermediate internally extending portion in collar 13 and divides collar 13 with two portions 16

Each one of portion 16 has a compression section 15 and a lead section 18 for guiding a pipe into compression section 15

Section 15 is divided into a fictional grip region 15a and a 5 compression region 1 5b having internal surfaces of different gradients

The gradient X ₃ of the friction grip region 1 5a as determined from a longitudinal axis 19 of collar 13 is steeper than the gradient Y ₃ of compression region 1 5b and ensures a progressively increasing radial force around a pipe when inserted into the collar 13 0 A rubberised ring 17a shown in cross section is fitted inside channel 17 to act as a shock absorber during the insertion of a pipe

The region 15b is of a thicker cross sectional area than region

15a thereby reinforcing compression region 15b

Lead section 18 is flexibly associated with region 15b by a reduced cross sectional at area thereby providing a weakened portion 18a 5 In addition as the second region 15b is reinforced, any deflection of the lead section 18 by surrounding material such as stones or rocks should not cause a disruption to a seal effected between the compression section 15 and a pipe

In Fig 4 it can be seen that two flush jointed pipes 20 and 21 l 0 are joined by collar 1 The flexible hinge 2 resides in groove 24 formed by a shoulder of an annular spigot 25 of pipe 20 and an edge face of a socket 26 of pipe 21

Although not shown in the illustration, it will be apparent to a skilled address see that any misalignment of the pipes 20 and 21 will ι " ^■ > cause a portion of flexible hinge 2 to expand with a contraction of a diametrically opposite portion of hinge 2 This therefore allows for misalignment of pipes due to either bad laying practice or ground movement in which damage to the seal is reduced or avoided

In use lead section 6 facilitates guiding respective pipes 20 0 and 21 into collar 1 Ideally sealant 31 is applied adjacent ends of pipes

20 and 21 which are to be inserted into collar 1

Accordingly, pipe 20 is guided into collar 1 , by lead portion 6 after which pipe 20 engages compression region 3b and frictional grip region 3a Frictional grip region 3a grips pipe 20 and compression region 5 3b provides a seal with sealant 31

Similarly, pipe 21 engages the opposite portion of collar 1 in which region 3a grip pipe 21 and region 3b from a seal with sealant 31

In Fig 5 there is shown an example of a collar 35 specially adapted for tne joining of flush jointed pipes to gutter boxes or man hole 0 facilities It can be seen that one portion of collar 35 comprises an outwardly tapering lead section 36 and a compression section 36a ending at a flexible hinge 36b The other portion of collar 35 is comprised of a

conduit 37 covered with a raised pattern 38 on an outer surface to facilitate the formation of a seal with concrete walls of a gutter box to which it is joined

In Fig 6 there is shown collar 35 as in FIG 5 joined to a gutter

5 DOX 42 In this illustration the cylindrical conduit of the collar 35 is perpendiculai to the gutter box 42 although it will be obvious to the skilled addressee that the conduit 37 may be cut at any angle and joined to the gutter box 42 from any direction

In use for example collar 7 may be used for joining two pipes ι 0 in which one of the pipes has a sealant applied to one end The pipe is inserted into collar 7 and is guided by lead section 12 into compression section 9 The pipe slides into both region 9a and 9b until it abuts flexible hinge 8 In a similar fashion the sealant is applied to an end of the other one of the pipes after which it is slid into the opposite compression l 5 section 9 until it abuts flexible hinge 8

It will be readily apparent to a skilled addressee that many modifications and variations may be made to the invention without departing from the scope thereof For example the liquid or other sealant used to form a water tight seal between the collar and a pipe may also be

20 a lubricant to facilitate easier insertion of the pipe

In addition the sealant may also be a chemical bonding agent between the material of the collar and the pipe, such that any imperfections in the finish of the outside of the pipe are accommodated with a relatively permanent seal achieved