AU709922B2 - Mould with pivotable mould portions - Google Patents

Description

This invention relates to moulding of material and in particular to a mould assembly having interchangeable, removable or moveable mould portions.

Within this specification and claims the following terms are used. The term "mould assembly" will be used to refer to an assembly for moulding an object of a desired shape. It is not intended, unless the context indicates otherwise, to refer to a mould apparatus within which a mould assembly is situated.

The term "mould section" is used to refer to a part of a mould assembly which with other co-operating mould sections can be put together to form the mould assembly. For example, where a mould assembly is formed of two halves each half is a mould section.

The term "mould portion" refers to a part of a mould section. A mould section of this invention may consist of a number of mould portions. Mould portions in some embodiments of the present invention can be removed, moved, inserted and interchanged to change the shape formed by the mould assembly.

The present invention may be useful in a number of different moulding processes including but not limited to blow moulding, vacuum forming and spin moulding.

General practice with blow moulding is to provide two mould sections each supported directly by a respective platen, or supported on a backing plate which can be secured to the platen. In use the mould sections are mounted onto the platens of the blow moulding apparatus either directly or by the backing plate so that the attached mould 20 sections can be moved together during the blowing of the mould and cooling of the *...*blown product, and separated to allow for retrieval of the blown product and introduction of a plastics parison.

Similarly with spin moulding plastic feed pellets are fed into the two mould halves which are then held together on the rotor, which is spun under heat to form the product, cooled, and the halves separated to release the product.

With vacuum forming generally the product is moulded against in a single mould section. Plastics feed is heated within the moulding apparatus, vacuum is applied to draw the piasticised feed against the mould section, the material is cooled, and the product is released. Where appropriate the product may be joined together with other halves.

The mould sections are generally formed from a unitary block of aluminium. Each mould section is usually used to form a single product, so that a different mould section is required should there even be a minor change in the shape of the product. The same applies equally in case for moulds for blow moulding, vacuum forming, or spin moulding.

Often a manufacturer will have a number of products that vary only in part from others but will require a separate mould for each of them. For example, three-way air conditioning ducting fittings may differ in diameter of the outlets. One fitting may have three connections of 600mm diameter. Another may have a 600mm, a 500mm and a 400mm diameter connection. Generally a range of branch fittings will be produced with combinations of outlets selected from a range between 100mm to 600mm. In other cases, the item shape may change in configuration, for example a three-way air conditioning ducting fitting to a four-way air conditioning fitting. In this case it may be desirable for the mould portions to be moved or rotated to form the desired mould section. Another example is where one three-way air conditioning ducting fitting is of shape and another is shaped.

At present apart from some very specific exceptions each variation of the product requires a totally new mould and because each mould is an expensive item the need for a great number of moulds for a reasonable product range means that the expense of setting up and maintaining an inventory of moulds is a very substantial expense.

To change production of one product to another, the moulds must be changed. The process of doing so is somewhat awkward and time consuming, and requires machinery 20 such as cranes to implement. Thus the various fittings such as cooling hoses and the like are removed. The weight of the moulds particularly taken together with the weight of the platen is usually more than can safely be managed manually, and a crane or other lifting device is required to support each of the mould sections whilst it is being taken off of the moulding apparatus, and when it is put into position. Not only is the operation cumbersome there is also potential for damage of the quite expensive mould and the more expensive moulding apparatus.

Additionally whilst the replacement of the mould is taking place the moulding apparatus is inoperable, and particularly where there is no on-site lifting device, the "timing of the changeover must be carefully co-ordinated to minimise any down-time.

30 In some manufacturing establishments it is known to provide some degree of variability in mould sections. Thus some variations can be taken into account by, for example, providing for an internal insert into a unitary mould section which can be used to modify the shape of the object. Additionally it is known to provide for a mould section that is made up of more than one mould portion, so that one or more of the mould portions can be interchanged or removed.

For some simple shapes where an interface between adjacent or interchangeable mould portions are consistent relative to the backing plate and other mould portions, eg. a straight plane, no great difficulty has been encountered. However this limits the usefulness of the mould to a restricted range of shape alternatives. It is found according to this invention that the range of shapes can be greatly expanded where the mould portions are moveable relative to others of the mould portions, such as by relative pivoting on the plane of the backing plate or platen. However it is difficult to consistently achieve accurate placement of the mould portion where there is relative pivoting. It is found that the difficulties can be overcome by providing a location means that can permit location of pivoting mould portions relative to one another over a range of pivotal movement.

It is an object of this invention to provide a mould section and assembly to obviate or minimise at least one of the aforementioned problems, or at least provide the public with a useful choice.

The invention may be said to reside, not necessarily in its broadest or only form, in a mould assembly consisting of: at least one mould section having at least one mould face within which is a mould cavity, the mould section including a plurality of mould portions: at least one of the mould portions being a removable mould portion; 20 and, at least a further two of the mould portions being pivotable mould S* "portions pivotal relative to one another so as to accommodate insertion or removal of the removable mould portion or portions; and, and location means being provided to permit accurate location of said at least two 25 pivotable mould portions relative to one another throughout a range of pivotal movement.

It will be appreciated that the mould section is adapted to permit the mould cavity to be changed by the relative movement, insertion and removal of the mould portions.

The location means preferably operates at a virtual or real apex formed by proximal location of the at least two pivotable mould portions. More preferably the location means comprises a first part on a first of the at least two pivotable mould portions, and a second part on a second of the at least two pivotable mould portions, the first part and the second part co-operating to permit pivoting about said apex, whilst still locating said two pivotable mould portions.

The first part of the location means preferably has an arcuate convex surface of the first of the at least two pivotable mould portions, and a complementary arcuate concave surface positioned on the second of the at least two pivotable mould portions so that when said two arcuate surfaces are in contact the two pivotable mould portions can pivot relative to one another maintaining contact thereby to locate the two pivotable mould portions one relative to the other.

For simplicity the arcuate convex surface and the complementary arcuate concave surface extends up to a moulding face of the mould portion and may take the form of elongate semi-cylindrical surfaces. This configuration assists with maintaining the continuity of the face of the mould section.

Alternatively much thinner arcuate surfaces may be desired and will be sufficient to act as locating means, and the arcuate convex surface may take the form of a disk shaped protrusion extending from the first of the pivotable mould portions which protrusion 7 extends into a disk shaped cavity of the second of the pivotable mould portions.

i Preferably the mould section also includes a retaining means to retain the mould portions on a backing plate or platen. It is to be understood that the mould portions may each be bolted or otherwise fixed using another form of fastener onto the backing plate or platen, •however because of the great degree of relative movement and configuration of the mould portions envisaged it is unlikely that an effective pattern of holes through the platen or backing plate will be possible to cover the range of configurations whilst still maintaining integrity of the backing plate and/or platen and providing for a reasonable variation in configuration. It may only be necessary to fix at least one of the mould portions to the backing plate or platen and to use an interlocking means (discussed later) to retain further mould portions to the platen or backing plate by reason of interaction with the mould portion that is fixed to the platen or backing plate.

S• Alternatively, and especially when no platen or backing plate is used, the retaining means may take the form of a band or frame clamping around the sides of the mould section to clamp the portions together, it may however not be possible (depending on the required mould) to have a sufficiently close fit between all the mould portions such that no voids are present within the mould section, and there may consequently not be sufficient uniformity of restraining pressure on all the mould portions to maintain them in position.

Preferably an interlocking means is provided that acts between at least some of the mould S b/y ortions to prevent relative movement of the mould portions away from either the platen or (a 0 backing plate. Such an interlocking means is preferably a detent between the mould portions. The detent may be part of the location means between the pivotable mould portions as described above wherein the locating means comprises a complementary disk and disk shaped slot, whereby the snug fit of the disk within the slot prevents relative movement away from the platen or backing plate. This arrangement thus provides not only for pivotal location, but also restraining relative movement away from the platen or backing plate.

Alternatively a detent may be provided independently of the locating means, by means of a tongue and slot arrangement whereby the tongue located on one of the mould portions registers with a complementary shaped slot within an adjacent or abutting mould portion.

Such detent may be used in addition to a retaining means such as a strap or frame around the periphery of the mould section clamping the mould portions together as discussed above.

Preferably a moulding face of the mould section which includes a moulding cavity is substantially flush having substantially no voids between the mould portions, at least adjacent to the moulding cavity. The reason being that during the moulding process some of the plastics material may be forced out of the moulding cavity and if there are voids it will accumulate in such voids resulting in a build up that requires cleaning and may S* interfere with the operation of the moulding process or at least with the exchange of mould portions. It may be desired to provide filler plates or blocks to fill voids produced by the pivoting of the pivoting mould portions this will further reduce voids on the moulding face of the mould section. It is anticipated that there will be some voids at the interface between mould portions leading to seams on the product which can simple by cut or broken away.

The number of mould sections needed will depend on the application to which the mould is put. For blow moulding and rotor (spin) moulding typically two mould sections are used, each mould section representing one half of the mould assembly, however certain versions of such techniques may use more than two mould sections and it is to be understood that the invention encompasses a mould section where more than two mould sections form the mould assembly. On the other hand for vacuum forming typically only one mould section comprises the mould assembly, and the invention can also be applied to vacuum forming.

The mould section in blow moulding is conveniently supported by a backing plate, which backing plate is then fastened to the platen of a blow moulding machine, alternatively the -mould section may be supported directly onto the platen.

In a preferred form the mould section is separable such that the plurality of mould portions comprise a number of blocks that can be pieced together to form the mould section each block extending substantially the depth of the mould section so that generally only one mould portion will cover a given area of the platen or backing plate. There may be some overlap of mould portions in the above form of the invention.

Alternatively the invention may also take the form wherein the mould portions do not extend the entire depth of the mould section, so that perhaps a recess is formed in a mould portion into which are positioned one or more other mould portions, the other mould portions preferably including the removable mould portion, and the said at least two pivotable mould portions.

Preferably a plurality of the mould portions are removable from the mould section whilst the platen and/or backing plate is in position within the moulding apparatus, so that the mould section can be modified whilst the mould is in position. Forms of this embodiment of the invention allow for total building up or taking down of a particular mould section in the moulding apparatus. For the majority of moulds envisaged, particularly where the mould are formed of aluminium, changing the mould can be achieved manually.

o4 In yet another form the mould section comprises at least three pivotable mould portions surrounding a non pivoting central mould portion, with locating means for locating the at least three pivotable mould portions relative to one other, the locating means adapted to provide for pivoting of the pivotable mould portions relative to one another, whereby at least the central mould portions and one of the pivotable mould portion are interchangeable o* and where at least two pivoting axes of the pivoting mould portions are not fixed.

Preferably the mould portions are supported on a platen or backing plate, and the pivotal axis extends outwardly from the platen, preferably the locating means is a rounded portion of a mould apex of a side of a respective mould portion, adapted to slide into a correspondingly shaped groove, extending away from the plane of the platen in an adjacent mould portion, and so as to allow for pivoting therebetween.

Preferably in this form and other forms each of the pivotable mould portions also includes a detent for interacting with a corresponding detent receiving means in an adjacent one of the pivoting mould portions to restrict separate movement of the mould portions away from the plane of the platen.

Preferably each of the mould portions of each mould section detent with adjacent mould portions. In a preferred form the detent include a tongue extending from a side of a mould portion adapted to be inserted into a slot within a side of another mould portion.

The invention may also be said to reside, though not necessarily in the broadest or only form, in a group of mould portions adapted to be formed into a mould section either by combination of some of the mould portions or by combination of all mould portions at least two of the mould portions being pivotable mould portions pivotal relative to one another so as to accommodate any one of a selected number of mould portions to fit therebetween and location means being provided to permit accurate location of said at least two pivotable mould portions relative to one another throughout a range of pivotal movement. By having a group of mould portions adapted to make a variety of mould sections a limited number of mould portions can make a number of mould shapes.

Further, the invention could also be said to reside, though not necessarily in the broadest or only form, in a method of moulding including the step of forming mould sections from the Sgroup of mould portions defined herein.

The invention might also be said to reside in a mould section made from the group of mould portions as defined herein.

S• Finally, the invention could also be said to reside, though not necessarily in the broadest or S o only form, in an object moulded using a mould section formed using any of the forms of the mould portions as described or defined herein.

It will be understood that the invention is not limited to simply a mould assembly.

S To assist in the understanding of the invention preferred embodiments will now be described with reference to the accompanying drawings: *o S: Figure 1 is a sketch of a mould section according to a first preferred embodiment prior to assembly; Figure 2 is a sketch of the mould section of Figure 1 assembled; Figure 3 is a sketch of an assembled mould section according to the first preferred embodiment illustrating the interchangeable and movable nature of mould portions; Figure 4 is a sketch of the mould section of Figure 2 mounted to a backing plate; Figure 5 is a perspective sketch of part of a mould portion according to the first preferred embodiment illustrating the tongue; Figure 6 is a perspective sketch of part of a mould portion according to the first preferred embodiment illustrating the slot; Figure 7 is a sketch of a second embodiment of the invention wherein two pivotable mould portions pivot around a single apex; Figure 8 is a cross-section view of a third embodiment of the invention through XIII-XIII of Figure 9; and, Figure 9 is a plan view from above of the third embodiment.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Dimensions of certain of the parts as shown in the drawings may have been either modified, exaggerated or both for the purpose of clarity of illustration.

For ease of illustration blow moulding fittings for air conditioning ducting will be used as the main example to explain the invention. However, it will be appreciated that the invention is not limited to this specific application or to blow moulding processes. It is believed that the invention can be applied, with necessary changes in details particular to the moulding process, to vacuum forming, rotor (spin) moulding and other forms of moulding.

The first illustrated embodiment is a blow moulding mould assembly. The mould assembly consists of two mould sections or halves each of which forms a half of the completed product. The mould assembly of the first illustrated embodiment is used to form a threeb way air conditioning duct branch fitting.

One of the mould sections is illustrated in Figure 1 prior to assembly and mounting on a platen. The mould section consists of four mould portions which cooperate to form the mould section as best seen in Figure 2. There is a central mould portion two identical pivotable mould portions and and pivotable mould portion identical to mould portion excepting that it has a channel for insertion therethrough of a blow pin for blowing a parison within the mould assembly. The mould section has a mould face (45) which in a mould assembly abuts another mould section. Within the mould Sportions 3, 4 and 5) are mould cavities (one indicated by 46).

Referring to Figures 1, 2, 3, 4, 5 and 6. The central mould portion has arcuate concave corners The pivotable mould portions 4 and 5) each have an arcuate convex surface which takes the form of a cylindrical edge section which is of complementary shape to the arcuate corners In addition to the cylindrical edge section each of the pivotable mould portions has a concave arcuate section (13) which is of substantially the same curvature as the cylindrical edge section.

When the mould section is being assembled and the mould portions are placed in position the various arcuate surfaces 8 and 13) of the mould sections permit accurate location of each mould portion relative to one another the matching and complementary arcuate surface give a positive location of the various mould portions. Additionally where mould portions of different sizes are required, for example were mould portion to be replaced by mould portion to provide for a smaller size outlet, a new central mould portion (14) is also required, being of different triangular shape to mould portion and the relative position of pivotable mould portion and is varied from that shown in Figure 2 by rotation about the virtual apex (20) formed between pivotable mould portions and The pivotable mould portions 4 and 5) also have an interlocking means to restrain 0 ::relative movement of the mould portions away from the platen when at least one of the mould portions is fixed to the platen. The interlocking means is a form of detent. A tongue extends from a side edge (10) of one of the pivotable mould portions and a slot (12) is formed in an adjacent side edge (11) of a second pivotable mould portion. As can be seen the tongue is of a generally triangular shape with an arc forming the side extending form the edge When put into place the tongue extends into the slot (12) to form a detent. This means to restrain relative movement in relation to the platen can best be seen separate in Figures 5 and 6 in perspective view and when positioned together in Figure 2 and 3.

In the illustrated example, the mould assembly can mould a three-way air conditioning duct with 500mm diameter apertures as illustrated in Figure 2. With the interchanged mould portions the three-way air conditioning duct moulded by the mould section illustrated in Figure 3, two apertures are 500mm in diameter and the other is 300mm in diameter.

The mould section illustrated in Figure 1 preferably is mounted to a backing plate (16) as illustrated in Figure 4 using known techniques.

11 Generally a cooling arrangement will be provided for and the most straight forward construction will be to provided for cooling it from the side to each of the mould portions.

It may be desirable for some or all portions to have ducts for the passing through of a cooling liquid and the portions are interconnected with tubes for fluid communication.

The second illustrated embodiment shown in Figure 7 is somewhat similar in application as the first illustrated embodiment. As with the first embodiment the mould section that is illustrated is for forming a three outlet (35) branch fitting for air conditioning ducting. Two pivotable mould sections (31, 32) are provided each pivotal relative to one another about a respective apex A similar arrangement of arcuate concave and convex surfaces is provided in conjunction with the central mould portion (34) to permit relative rotation to accommodate variation in sizes of the all three outlets. A fourth mould portion (36) forms the third branch outlet and is put into position and located relative to the central mould portion by ridge (37) which register into corresponding groove (38).

The provision of the one pivotal locating means which permits accurate placement of pivotable mould portions (31, 32) over a range of pivotal movement facilitates the assembly of a variety of three branch outlets differing in the diameter of the outlets, but using common mould portions. The common mould portions may also be used to expand the mould to one that might be used for a branch fitting with four or more outlets.

The third illustrated embodiment shown in Figures 8 and 9 shows an alternative locating means between adjacent pivotable mould portions. In place of the arcuate surfaces acting to locate a plate (40) is fastened to a first of the pivotable mould portions by a screw (41) Swithin a recess (42) in the first of the pivotable mould portions. The plate (40) extends to a second pivotable mould portion and an end of the plate include a finger (43) which located within a groove (44) in the second pivotable mould portion.

The mould portions can be made of known materials using known techniques. In the case of blow moulding aluminium is a preferred material as the weight of each portion is considerable less than if made of steel. This facilitates changing and moving mould portions.

It will be appreciated that the mould portions can be used to change the general shape of a moulded item or to change a surface feature such as patterning.

Further, it will be appreciated that the interlocking means of the illustrated tongue and slot is not intended to be the only interlocking or detent means applicable to the invention.

12 Other interlocking means, such as fixing plates, will be apparent to a skilled addressee and would be within the scope of the invention disclosed herein.

99 Weoo 9 Se 13 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:- 1. A mould assembly consisting of: at least one mould section having at least one mould face within which is a mould cavity, the mould section including a plurality of mould portions: at least one of the mould portions being a removable mould portion; and, at least a further two of the mould portions being pivotable mould portions pivotal relative to one another so as to accommodate insertion or removal of the removable mould portion or portions; and, and location means being provided to permit accurate location of said at least two pivotable mould portions relative to one another throughout a range of pivotal movement, said pivotal movement allowing the size of the mould cavity to be adjusted.

2. A mould assembly as in Claim 1 wherein the mould cavity can be increased or reduced in size by pivoting the at least two pivotable mould portions relative to one o 15 another between first and second arcuate positions, to thereby accommodate the at least one removable mould portion therebetween and abutting the adjacent mould faces.

3. A mould assembly as in Claim 2 wherein the location means operates at a virtual or real apex formed by proximal location of the at least two pivotable mould portions.

S" 20 4. A mould assembly as in Claim 3 wherein the location means comprises a first part on a first of the at least two pivotable mould portions, and a second part on a second of the at least two pivotable mould portions, the first part and the second part co-operating to permit pivoting about said apex, whilst still locating said two pivotable mould portions.

5. A mould assembly as in Claim 4 wherein the first part of the location means has an arcuate convex surface on the first of the at least two pivotable mould portions, and a complementary arcuate concave surface positioned on the second of the at least two pivotable mould portions so that when said two arcuate surfaces are in contact the two pivotable mould portions can pivot relative to one another maintaining contact thereby to locate the two pivotable mould portions one relative to the other.

6. A mould assembly as in Claim 5 wherein the first part protrudes from the first of the at least two pivotable mould portions.

Claims (17)

1. 7. A mould assembly as in either Claim 5 or Claim 6 wherein the arcuate convex surface and the complementary arcuate concave surface extends along a side of the respective mould portion to the mould face of the mould section.
2. 8. A mould assembly as in Claim 7 wherein the arcuate convex surface and the complementary arcuate concave surface substantially take the form of elongate semi- cylindrical surfaces.
3. 9. A mould assembly as in either Claim 5 or Claim 6 wherein the arcuate convex surface is of a disk shaped protrusion extending from the first of the pivotable mould portions and which protrusion extends into a disk shaped cavity of the second of the pivotable mould portions. A mould assembly as in any one of the above claims wherein the mould section S. includes a retaining means to restrain relative movement of the mould portions away from a backing plate or platen to thereby retain the mould portions on the backing plate or platen. 15 11. A mould assembly as in Claim 10 wherein the platen includes a plurality of fixing holes and the mould portions may each be bolted or otherwise fixed using the holes to the platen. •12. A mould assembly as in Claim 10 wherein the backing plate includes a plurality of fixing holes and the mould portions may each be bolted or otherwise fixed using the 20 holes to the backing plate.
4. 13. A mould assembly as in any one of Claims 1 to 9 wherein the mould section includes a retaining means in the form of a band or frame clamping around the sides of the mould section to clamp the mould portions together.
5. 14. A mould assembly as in Claim 10 or Claim 13 wherein the mould section includes an interlocking means, said interlocking means acting between adjacent mould portions to restrain relative movement of the mould portions away from a backing plate or platen to thereby retain the mould portions on the backing plate or platen. A mould assembly as in Claim 9 wherein an interlocking means is a detent and part of the location means between the pivotable mould portions whereby a snug fit of the disk shaped protrusion within the disk shaped cavity prevents the relative movement.
6. 16. A mould assembly as in any one of the proceeding claims excepting Claim cluding a detent between mould portions consisting of a tongue and slot arrangement U-: 0 whereby the tongue located on one of the mould portions registers with a complementary shaped slot within an adjacent or abutting mould portion.
7. 17. A mould assembly as in Claim 16 wherein the detent is in addition to a retaining means adapted to hold the mould portions together or to a platen or backing plate.
8. 18. A mould assembly as in any one of the proceeding claims wherein the mould face of the mould section has substantially no voids between the mould portions, at least adjacent to the mould cavity.
9. 19. A mould assembly as in Claim 18 including filler plates or blocks to fill voids produced by the pivoting of the pivotable mould portions so as to reduce voids in the mould face of the mould section. A mould assembly as in any one of the proceeding claims wherein one of the mould portions includes a recessed cavity in the mould cavity surface into which another member can be inserted into the recessed cavity to change the shape of the mould cavity surface. *oo*
10. 21. A mould assembly as in any one of the proceeding claims wherein the mould portions are removable from the mould section whilst a platen or backing plate or both is in position within a moulding apparatus. S 22. A mould assembly including a mould section comprising at least three pivotable mould portions surrounding a non pivoting central mould portion, with location means for locating the at least three pivotable mould portions relative to one another, the S: location means being adapted to provide for pivoting of the pivotable mould portions relative to one another, at least the central mould portion and one of the pivotable °*omould portions being changeable with other central mould portions and pivotable mould portions respectively, and where at least two pivot axes of the pivotable mould portions are not fixed.
11. 23. A mould assembly as in Claim 22 wherein the mould portions are supported on a platen or backing plate, and the pivot axes extends outwardly from the platen or backing plate, the location means is a rounded portion of a mould apex of a side of a respective mould portion, adapted to slide into a correspondingly shaped groove, extending away from the plane of the platen in an adjacent mould portion, and so as to allow for pivoting therebetween.
12. 24. A mould assembly as in either Claim 22 or 23 wherein each of the pivotable mould portions also includes a detent for interacting with a corresponding detent H i 16 receiving means in an adjacent one of the pivoting mould portions to restrict separate movement of the mould portions. A mould assembly as in Claim 24 wherein each of the mould portions of the mould section detent with adjacent mould portions.
13. 26. A mould assembly as in either Claim 24 or Claim 25 wherein the detent include a tongue extending from a side of a mould portion adapted to be inserted into a slot within a side of another mould portion.
14. 27. A group of mould portions adapted to be formed into a mould section within which is a mould cavity either by combination of some of the mould portions or by combination of all mould portions, at least two of the mould portions being pivotable mould portions pivotal relative to one another so as to accommodate any one of a selected number of mould portions to fit therebetween, said at least two pivotable mould portions including location means adapted so that when the mould section is formed the location means permits accurate location of said at least two pivotable mould portions relative to one another throughout a range of pivotal movement to thereby allow the size of the mould cavity to be adjusted as a result of said pivotal movement.
15. 28. A method of moulding including the step of forming a mould assembly as defined in claims 1 to 26. S 20 29. A mould section made from a group of mould portions, the mould portions being as herein defined. An object moulded using a mould assembly as defined in claims 1 to 26.
16. 31. A mould apparatus including a mould assembly as defined in claims 1 to 26.
17. 32. A mould assembly substantially as herein described with reference to the accompanying drawings. Dated this 9th day of July 1999 NORDIN ENGINEERED AIR TECHNOLOGIES PTY LTD By their Patent Attorneys A.P.T. Patent and Trade Mark Attorneys ABSTRACT A mould consisting of a number of portions the configuration of which is adjustable. The portions permit rotation of one in respect to another thereby permitting a mould to be varied in form permitting different articles to be moulded using the same mould portions. A convex part of a portion co-operates and abuts with a concave part of another thereby providing a pivot point and a continuous mould surface for varying angular configuration of the portions. Detent means of a slot in one portion and a tongue extending from another portion aid in the fixing of the portions relative to each other. The tongue can be somewhat triangular in shape with an arc forming the side extending from the portion so that as the portion is rotated with respect to another the tongue co-operatively inserted into or withdrawn from the slot of the other portion. Further, the mould can also include removable and exchangeable portions. o