AU2002301030B1

AU2002301030B1 - Moulding of Hollow Items

Info

Publication number: AU2002301030B1
Application number: AU2002301030A
Authority: AU
Inventors: John Terry Forehan
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-11-12
Filing date: 2002-09-13
Publication date: 2003-02-20
Anticipated expiration: 2022-09-13
Also published as: AU2002301030B9

Description

13. SEP. 2002 15:57 WRAY AND ASSOCIATES NO. 045 P. P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Actual Inventor Address for service is: Mr John Terry Forehan Mr John Terry Forehan WRAY ASSOCIATES 1 William Street Perth, WA 6000 Attorney code: WR Invention Title: "Forming of Hollow Items" Details of Associated Provisional Application No(s): PR8825 filed on 12 November 2001 The following statement is a full description of this invention, including the best method of performing it known to me:- 13. SEP. 2002 15:57 WRAY AND ASSOCIATES NO. 045 P. 6 -2- "Forming of Hollow Items" Field of the Invention This invention relates to forming of hollow items which can include items such as pipes, pipe connectors and the like and can include items which are formed by injection moulding and which are required to have recesses formed in their interior faces and/or zones in the internal faces of the item which have a radial extent greater than the minimum internal radius of the item and particularly at one or more of the outer ends of the items.

Background In the forming of hollow items such as pipes and pipe connectors and like items, utilising conventional moulding techniques it is often the requirement that the internal face of the moulded item be formed with a recess such as an annular groove which is intended to accommodate a sealing ring or the like. Another example of such a recess relates to the need to provide a connection between a pair of interconnected pipes which will enable the pipes to have a degree of pivotal movement about an axis which is transverse to the interconnection between the pipes. The difficulty in forming such recesses relates to the need to utilise an internal former which will provide the recess in the moulded item and after the item has been formed to subsequently be able to remove the intemrnal former on completion of the moulding process.

As an example of the application of the invention in the utilisation of plastic injection in the moulding of items a variety of techniques have been used in forming the internal recesses. One of these techniques has comprised utilisation of a central former or an internal former which is received over a central former, which has the desired external radial configuration which is complementary to the desired internal configuration of the hollow item where the former is formed of a low melting point metal. On completion of the moulding process the moulded item together with the central former is removed from the mould and the moulded item together with the central former is located in a heated oil bath which is held 13. SEP. 2002 15:57 WRAY AND ASSOCIATES NO. 045 P. 7 -3at a temperature greater than the melting point of the metal of which the central former is made but lower than the melting point of the plastics utilised in the moulded item in order that the central former melts and so doing is eliminated from the interior of the moulded item. Whilst this practice is quite satisfactory it is extremely labour and energy intensive in that it requires the initial formation of the central former by a separate process and the subsequent removal of the central former from the moulded product by an additional process which involves destruction of the former. As a result the former can only be used once.

Another method comprises utilisation of a central former which is capable of being expanded radially to provide the recess forming portion whereby on completion of the moulding process the central former is radially contracted out of engagement with the formed recess to enable the former to be removed from the moulded item. An example of such an arrangement is disclosed in US 3966385 and US4044092 which illustrate a mechanical form of a central former which has an expandable portion. A difficulty with such arrangements relates to cost in the manufacture of such formers which must be customised according to each moulded product which is to be made. Another example of such a practice is disclosed in US 5080576 and JP2258218 which utilize a resiliently compressible ring which is compressed axially between a pair of clamping members such that it will be extruded outwardly from the surface of the former and define a forming surface which can be used to form an annular groove.

Such an arrangement is extremely limited in terms of its application in that it can only be utilised in the formation of a simple annular groove in the internal surface and has limited application in formation of recesses which have a relatively complex and/or axially extensive configuration.

Another method of formation has been disclosed in JP9314618 which relates to the location of a ring body around a core whereby the moulded item is formed with a groove as a result of the presence of the ring body and whereby on removal of the moulded item from the mould the ring body can be resiliently extracted from the moulded item. A problem with this method relates to the difficulty in positively locating the ring body within the moulding chamber in a manner such that it will not be caused to move axially whilst the mould is being 13. SEP. 2002 15:58 WRAY AND ASSOCIATES NO. 045 P. 8 -4set up and during the moulding process but which also enables the central former to be removed from the moulding chamber on completion of the moulding process. A variation of this process is also disclosed in US 4263249 which involves the use of a composite ring which is to be located on the primary former and on the setting of the material around the former the primary former is removed and the composite ring is disassembled. This process also suffers from the absence of a positive location of the composite ring on the primary former as well as the destruction or disassembly of the composite ring to enable its removal from the moulded item Another method has been disclosed in US 4352652 which utilises a pair of axially opposed formers which are brought together to define a groove in the internal face of the combined forming surface to create a radial rib intermediate of the length of a pipe connector. In addition the formers are each provided with a sleeve which is able to move axially to create an annular recess in the inner face of the outer former into which the plastics material is deformed to produce an annular groove on the inner face of the connector. This arrangement involves the use of a complex internal former and the controlled use of fluid pressure to deform the plastics material into the annular recess which results in only the outer face of the moulded item in the region of the recess being accurately formed. A similar arrangement is disclosed in US4100307. In addition US 4107249 discloses a similar arrangement which also uses a expandable annular former to supplement the moulding action achieved through fluid pressure.

The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge anywhere in the world as at the relevant priority dates of the application.

Disclosure of the Invention Accordingly the invention resides in a mould for use in the moulding of a hollow item, where the hollow item has an internal recess in the inner face, the mould 13. SEP. 2002 15:58 WRAY AND ASSOCIATES NO. 045 P. 9 comprising a substantially central former which has parallel and/or tapered side walls and which is received within the mould to define a generally annular moulding chamber between the interior face of the mould chamber and the external face of the former, the central former being displaceable axially into and out of the moulding chamber, the annular chamber being closed at each end, the mould further comprising an resiliently deformable former received over the central former and supported by the mould and/or central former to be retained in position within the moulding chamber to be resistant to at least some axial movement on the central former, the outer radial face of the deformable former being shaped to form a recess in the internal surface of the moulded item, said deformable former being formed of a resiliently deformable material which is resistant to the heat and/or pressures generated in the moulding chamber during the moulding process, said central former being capable of axial movement out of engagement with the deformable former when the deformable former is located in the moulding chamber.

Accordingly the invention also resides in a mould for use in the moulding of a hollow item, where the hollow item has an internal recess in the inner face, the mould comprising a substantially central former which has parallel and/or tapered side walls, the mould further comprising an resiliently deformable former received over the central former and supported by the central former to be retained in position to be resistant to at least some axial movement on the central former, the outer radial face of the deformable former being shaped to form a recess in the internal surface of the moulded item, said deformable former being formed of a resiliently deformable material which is resistant to the heat and/or pressures generated during the moulding process, said central former being capable of axial movement out of engagement with the deformable former on completion of the moulding of the hollow item to leave the deformable former in the hollow item for subsequent removal.

According to preferred feature of the invention the deformable member is supported by the mould and/or central former at its end faces 13. SEP. 2002 15:58 WRAY AND ASSOCIATES NO. 045 P. -6- According to a preferred feature of the invention the deformable former is frictionally engaged with the central former.

According to a further preferred feature of the invention the deformable former is supported by at least one end face of the moulding chamber.

According to a further preferred feature of the invention the deformable former is supported between the opposed end faces of the moulding chamber.

According to a further preferred feature of the invention the deformable former is supported at one end by an end face of a moulding chamber and at its other end by an abutment on the central former. According to a preferred feature of the invention the central former has a reduced radial dimension between the abutment and the one end. According to a preferred feature of the invention the abutment is located to be received within the moulding chamber.

According to a further preferred feature of the invention the deformable former is supported from a portion of the central former having an enlarged diameter.

According to a further preferred feature of the invention the portion comprises an abutment formed by a reduction in diameter of the central former wherein the central former has a reduced radial dimension between the abutment and the one end. According to one embodiment the abutment comprises a tapered portion of the central former. According to another embodiment the abutment comprise an annular face. According to a preferred feature of the invention the abutment engages one end of the deformable former. According to an alternative preferred feature of the invention the abutment engages the inner bore of the deformable former intermediate of its ends. According to a preferred feature of the invention the other end of the deformable former is engaged by an end face of a moulding chamber. According to a preferred feature of the invention the abutment is located to be received within the moulding chamber.

According to a further preferred feature of the invention the deformable former is formed as a single integral element.

13. SEP. 2002 15:59 WRAY AND ASSOCIATES NO.045 P. 11 -7- According to a further preferred feature of the invention said deformable former comprises a plurality of annular elements that are to be located in end to end relationship on the central former.

According to a preferred feature of the invention the central former is formed of at least two members wherein at least one of the members receives the deformable member. According to a preferred feature of the invention the members are receivable within the moulding chamber in opposed relation to each other.

Accordingly the invention also resides in a method of moulding a hollow item where the method uses a mould associated with a substantially central former which has parallel and/or tapered side walls which is received within the mould to define a annular moulding chamber between the interior face of the mould chamber and the external face of the former, the central former being displaceable axially into and out of the moulding chamber, the annular chamber being closed at each end, said method comprising applying over the central former a deformable former formed of a resiliently deformable material which is resistant to the heat andlor pressures generated in the moulding chamber, locating the central former with the deformable former in the mould, supporting each end of the deformable former within the moulding chamber from the mould and or the former, introducing a moulding composition into the moulding chamber, allowing the moulding composition to harden, axially extracting the central former from the moulded item, resiliently deforming the deformable former and removing it from within the moulded item.

According to a preferred feature of the invention the method involves injection moulding.

Accordingly the invention also resides in a method of moulding a hollow item where the method uses a mould comprising a central former which has parallel and/or tapered side walls and a deformable former formed of a resiliently deformable material which is resistant to the heat and/or pressures generated in performance of the method, the deformable former being supported by the central former to be retained in position to be resistant to at least some axial 13. SEP. 2002 15:59 WRAY AND ASSOCIATES NO.045 P. 12 -8movement on the central former, said method comprising locating the deformable former on the central former, applying a moulding composition around the mould, allowing the moulding composition to harden, axially extracting the central former from the moulded item, resiliently deforming the deformable former and removing it from within the moulded item.

The invention will be more fully understood in the light of the following description of several specific embodiments.

Brief Description of the Drawing The description is made with reference to the accompanying drawing of which is a schematic sectional elevation of a moulding chamber incorporating a deformable former according to the first embodiment.

Detailed Description of Specific Embodiment The first embodiment of the invention comprises a mould which can be utilised in the formation of pipe connectors by plastics injection moulding where the pipe connector is to be capable of providing a connection between the adjacent ends of two lengths of pipe. As a result the connector has an annular recess formed in its intemrnal face at each end where the recess which is capable of receiving a sealing O-ring.

The first embodiment comprises a mould 11 defining a moulding chamber 13 which has an external configuration according to the desired external configuration of the moulded item. The mould 11 is formed of two separable portions which can be separated to enable access to the interior of the moulding chamber 13 and for removal of the moulded item on completion of the moulding process. The mould 11 is associated with a cylindrical central former 15 which is to be received within the moulding chamber 13 and is capable of axial movement into and out of engagement with the moulding chamber 11. The portion of the central former which is accommodated within the moulding chamber is formed to have a reduced diameter to provide an abutment face 25 at one end of the moulding chamber which closes the moulding chamber at that end.

13. SEP. 2002 15:59 WRAY AND ASSOCIATES NO.045 P. 13 In use the moulding chamber mould 11 is closed and the central former 15 is locatedwithin the moulding chamber 13 to close the moulding chamber. Plastics material is then injected into the moulding chamber 13 and once the plastics material has solidified the central former 15 is removed and the mould 11 is opened to provide access to the moulded item.

The first embodiment relates to modification of the existing moulding arrangement described above to enable the moulded item to have a convoluted internal configuration. The first embodiment comprises utilisation of a deformnable former which comprises a set of annular elements 17, 19, 21 and 23 which are intended to be located in an end to end relationship on the central former 15 such that the elements 11, 19 21 and 23 jointly provide a single moulding surface between the abutment 25 on the central former and the opposed end face 27 of the moulding chamber 13. The elements 17, 19 21 and 23 of the deformable former are formed of a substantially rigid yet resiliently deformable elastomeric, rubber, plastics or like material which when used in the moulding chamber provides a solid surface and one which is able to withstand the heat and pressure generated within the moulding chamber 13 by the -moulding process and yet is capable of some resilient deformation when not supported on the central former 15 to facilitate its removal from the moulded item.

The elements 17, 19, 21 and 23 are configured such that when the deformable former is located in the moulding chamber 13 between the abutment 25 and the end face 27 of the moulding chamber, the elements 17 are in close abutting relationship with the adjacent elements the end elements 17 and 23 are in close abutting relationship with the abutment 25 and the end face 27. The elements 17, 19, 21 and 23 which form the deformable former comprise a pair of end elements 17 and 23 which are configured to define internal annular recesses in the moulded item which will accommodate a suitable 0-ring and a pair of central elements 19 and 21 which serve as spacer elements between the end elements 17 and 23 have a generally divergent outer annular face from the end elements 17 and 23 in order to provide an internal configuration within the moulded member which is substantially bulbous.

13. SEP. 2002 16:00 WRAY AND ASSOCIATES NO. 045 P. 14 10 In use the deformable former in the form of the elements 17, 19, 21 and 23 is axially engaged over the central former 15 and once in position the mould is closed whereby the free ends of the end elements are supported by the end faces of the moulding chamber. The moulding'chamber 13 is then filled by the molten plastics material. On completion of the moulding process the central former 15 is axially retracted from the moulding chamber 13 and in so doing the central former is extracted from engagement with the deformable former. The mould is then opened to enable the moulded item containing the deformable former to be then extracted from the mould. Each of the elements 17, 19, 21 and 23 which make up the deformable former are then resiliently deformed and extracted from the internal bore of the moulded item in order that they can be used again.

The first embodiment provides a means of forming a moulded item by plastics injection moulding where the moulded item has a convoluted internal face which reduces the energy and labour which has been previously required in methods which have used a former formed of a low melting point metal. As a result of the embodiment the deformable former can be extracted from the mouldable item to be used again. Furthermore the first embodiment provides a means of moulding plastics injection item in which the capital costs of the moulding former is significantly reduced when compared to arrangements which have been utilized in the past which have used an expanding mechanically expandable central former in that the deformable former can be relatively inexpensive in its manufacture and does not require regular maintenance to ensure that various mechanical elements are operating effectively. Furthermore the first embodiment provides a means whereby the former which is required to form the convoluted internal faces can be positively located in position which serves to ensure quality control of the final product. Finally the first embodiment provides a means of forming a moulded product where the internal configuration of the hollow item can be relatively complex.

According to a second embodiment of the invention (not shown) the deformable former occupies only a portion of the internal face of the moulding chamber and is located on the outer end portion of the central former 15. In the case of the 13. SEP. 2002 16:00 WRAY AND ASSOCIATES NO.045 P. -11 second embodiment the outer end portion of the central former is formed with a reduced diameter portion to provide an abutting end face at the inner most end of the reduced diameter portion whereby the deformable former is received between the end face of the reduced diameter portion and the opposed end face of the moulding chamber. On completion of the moulding step the central former is capable of axial withdrawal from the moulding chamber in a direction away from the opposed end face of the moulding chamber in order that the central former 15 can be extracted from the deformable former when located in the moulded product.

According to a third embodiment which is an alternative to the previous embodiments the central core may be formed as a composite element which is formed of a number of elements which are introduced into the moulding chamber to support the deformable former but which can be readily withdrawn from the mould subsequent the other moulding action to provide access to the deformable former in order that the deformable former can be defonrmed and extracted from the moulded item, Such an arrangement could be used on the moulding of a tubular T-piece.

According to a fourth embodiment of the invention the deformable former is formed as a single element.

According to a fifth embodiment the mould comprises a central former only and the moulding process comprises application of a material to be moulded over the former. The embodiment has application where the internal configuration must be precise whereas the external configuration need not be precise. In such an instance the moulding material comprises a settable composition which is applied over the central former and is allowed to harden. The mouldable material may include a fibrous material whereby the material is wrapped around the former. The central former includes a deformable former of the same form as has been described in relation to previous embodiments where at least one end of the deformable former abuts against an the annular face defined by a reduced diameter portion of the central former where the reduced diameter portion extends to one end of the central former. In use once the mouldable material 13, SEP. 2002 16:00 WRAY AND ASSOCIATES NO. 045 P. 16 -12has set the central former is removed axially from the moulded item to leave the deformable former in place. The deformable former is then removed from the moulded item by resiliently deforming the deformable former inwardly and extracting it axially from the moulded item.

According to a sixth embodiment of the invention which is a variation of each of the above embodiments at least apart of the portion of the central former which accommodates the deformable former is formed with an annular shoulder intermediate of the length of the portion where the shoulder is formed by a reduced diameter of the central former and the remainder of the central former extending from the shoulder has a diameter at most equal to that of the reduced diameter. The shoulder will retain the deformable portion in place and on completion of the moulding process will enable the removal of the central former from the moulded item and deformable former. Where the central former is used with an outer mould the end of the deformable former free end of the remainder of the central former is supported by the adjacent end face of the mould.

According to a seventh embodiment of the invention which is a variation of each of the above embodiments at least apart of the portion of the central former which accommodates the deformable former is tapered and the end of the central former extending from the reduced diameter end of the portion has a diameter at most equal to that of the reduced diameter. The tapered configuration of portion of the central former will retain the deformable portion in place and on completion of the moulding process will enable the removal of the central former from the moulded item and deformable former. Where the central former is used with an outer mould the end of the deformable former at the reduced diameter end of the central former is supported by the adjacent end face of the mould.

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

13. SEP. 2002 16:00 WRAY AND ASSOCIATES NO. 045 P. 17 -13- It should be appreciated that scope of the present invention need not be limited to the particular scope of the embodiments described above 13. SEP. 2002 16:02 WRAY AND ASSOCIATES NO. 045 P. 24 1 /1

Claims

13. SEP. 2002 16:01 WRAY AND ASSOCIATES NO.045 P. 18 -14- Claims The claims defining the invention are as follows: 1. A mould for use in the moulding of a hollow item, where the hollow item has an internal recess in the inner face, the mould comprising a substantially central former which has parallel andlor tapered side walls and which is received within the mould to define a generally annular moulding chamber between the interior face of the mould chamber and the external face of the former, the central former being displaceable axially into and out of the moulding chamber, the annular chamber being closed at each end, the mould further comprising an resiliently deformable former received over the central former and supported by the mould and/or central former to be retained in position within the moulding chamber to be resistant to at least some axial movement on the central former, the outer radial face of the deformable former being shaped to form a recess in the internal surface of the moulded item, said deformable former being formed of a resiliently deformable material which is resistant to the heat and/or pressures generated in the moulding chamber during the moulding process, said central former being capable of axial movement out of engagement with the deformable former when the deformable former is located in the moulding chamber, 2. A mould as claimed at claim 1 wherein the deformable member is supported by the mould and/or central former at its end faces 3. A mould as claimed at claim 1 or 2 wherein the deformable former is additionally frictionally engaged with the central former. 4. A mould as claimed at claim 1 or 2 or 3 wherein the deformable former is supported by at least one end face of the moulding chamber. A mould as claimed at claim 4 wherein the deformable former is supported between the opposed end faces of the moulding chamber. 13. SEP. 2002 16:01 WRAY AND ASSOCIATES NO. 045 P. 19 6. A mould as claimed at claim 4 wherein the deformable former is supported at one end by an end face of a moulding chamber and at its other end by an abutment on the central former. 7. A mould as claimed at claim 6 wherein the central former has a reduced radial dimension between the abutment and the one end, 8. A mould as claimed at claim 7 wherein the abutment is located to be received within the moulding chamber. 9, A mould as claimed at claim 4 wherein the deformable former is supported from a portion of the central former having an enlarged diameter. 10. A mould as claimed at claim 9 wherein the portion comprises an abutment formed by a reduction in diameter of the central former wherein the central former has a reduced radial dimension between the abutment and the one end. 11.A mould as claimed at claim 10 wherein the abutment comprises a tapered portion of the central former. 12.A mould as claimed at claim 10 wherein the abutment comprises an annular face. 13.A mould as claimed at claim 10 or 11 or 12 wherein the abutment engages one end of the deformable former.

14.A mould as claimed at claim 10 or 11 or 12 wherein the abutment engages the inner bore of the deformable former intermediate of its ends. mould as claimed at claim 13 or 14 wherein the other end of the deformable former is engaged by an end face of a moulding chamber.

16.A mould as claimed at any one of claims 6 to 8 and 10 to 15 wherein the abutment is located to be received within the moulding chamber.

18. OCT. 2002 9:17 WRAY AND ASSOCIATES NO. 770 P, -16- 17.A mould as claimed at any one of the preceding claims wherein the deformable former is formed as a single integral element. 18.A mould as claimed at any one of the preceding claims wherein said deformable former comprises a plurality of annular elements that are to be located in end to end relationship on the central former.

19.A mould as claimed at any one of the preceding claims wherein the central former is formed of at least two members wherein at least one of the members receives the deformable member. mould as claimed at claim 19 wherein the members are receivable within the moulding chamber in opposed relation to each other.

21.A mould for use in the moulding of a hollow item, where the hollow item has an internal recess in the inner face, the mould comprising a substantially central former which has parallel and/or tapered side walls, the mould further comprising an resiliently deformable former received over the central former and supported by a portion of the central former to be retained in position to be resistant to at least some axial movement on the central former, the outer radial face of the deformable former being shaped to form a recess in the internal surface of the moulded item, said deformable former being formed of a resiliently deformable material which is resistant to the heat and/or pressures generated during the moulding process, said central former being capable of axial movement out of engagement with the deformable former on completion of the moulding of the hollow item to leave the deformable former in the hollow item for subsequent removal.

22.A mould as claimed at claim 21 wherein the deformable former is frictionally engaged with the portion of the central former.

23.A mould as claimed at claim 21 or 22 wherein the deformable member is axially supported from one end of the central former. 18.OCT. 2002 9:18 WRAY AND ASSOCIATES NO. 770 P. 6 -17-

24.A mould as claimed at claim 21 or 22, or 23 wherein the portion comprises an abutment formed by a reduction in diameter of the central former wherein the central former has a reduced radial dimension between the abutment and the one end.

25.A mould as claimed at claim 24 wherein the abutment compn'ses a tapered portion of the central former.

26.A mould as claimed at claim 24 wherein the abutment comprises an annular face.

27.A mould as claimed at claim 24 or 25 or 26 wherein the abutment engages one end of the deformable former.

28.A mould as claimed at claim 24 or 25 or 26 wherein the abutment engages the inner bore of the deformable former intermediate of its ends.

29.A mould as claimed at any one of claims 21 to 28 wherein the deformable former is formed as a single integral element.

30.A mould as claimed at any one of claims 21 to 29 wherein said deformable former comprises a plurality of annular elements that are to be located in end to end relationship on the central former.

31.A mould as claimed at any one of claims 21 to 30 wherein the central former is formed of at least two members wherein at least one of the members receives the deformable member.

32.A mould substantially as herein described.

33.A method of moulding a hollow item where the method uses a mould associated with a substantially central former which has parallel and/or tapered side walls which is received within the mould to define a annular moulding chamber between the interior face of the mould chamber and the external face of the former, the central former being displaceable 18. OCT. 2002 9:18 WRAY AND ASSOCIATES NO. 770 P. 7 -18- axially into and out of the moulding chamber, the annular chamber being closed at each end, said method comprising applying over the central former a deformable former formed of a resiliently deformable material which is resistant to the heat and/or pressures generated in the performance of the method, locating the central former with the deformable former in the mould, supporting each end of the deformable former within the moulding chamber from the mould and or the former, introducing a moulding composition into the moulding chamber, allowing the moulding composition to harden, axially extracting the central former from the moulded item, resiliently deforming the deformabfe former and removing it from within the moulded item.

34.A method as claimed at claim 33 wherein the method involves injection moulding. method of moulding a hollow item where the method uses a mould comprising a central former which has parallel and/or tapered side walls and a deformable former formed of a resiliently deformable material which is resistant to the heat and/or pressures generated in the performance of the method, the deformable former being supported by the central former to be retained in position to be resistant to at least some axial movement on the central former, said method comprising locating the deformable former on the central former, applying a moulding composition around the mould, allowing the moulding composition to harden, axially extracting the central former from the moulded item, resiliently deforming the deformable former and removing it from within the moulded item.

36.A method substantially as herein described. Dated this thirteenth day of September 2002. John Terry Forehan Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant(s)