GB2038700A - Blow or injection moulding of complex articles - Google Patents

Abstract

Blow moulding and injection methods are disclosed for making a hollow, shaped article such as a dispenser for a flowable material, from plastics or glass. For blow moulding, a parison 87 (figure 11) or 43 (figure 7) is positioned in a mould cavity 91 or 42 which has a closed end 90 or 49. A blow pin 89 or 47 is extended into the parison, which is preferably clamped between a mould collar 46 (figure 7) and the blow pin 47. The opposite end of the parison is compressed by the blow pin to conform to the shape of the blow pin and mould cavity, and is inflated so that is assumes the shape of the mould cavity and, after cooling, is ejected from the mould. The shaped article can also be injection moulded between a complex-shaped mould and core. The preferred article is a dispenser 80 (figure 10) having a conical nozzle 83 and cap 84 which are broken off the dispenser body for screwing into threads 81. The nozzle 83 can be externally stepped. <IMAGE>

Description

SPECIFICATION Method of making a hollow, shaped article and apparatus therefor This invention relates generally to a method of making a hollow, shaped article and an apparatus therefor.

More particularly the invention relates to a method and apparatus for shaping an article in one piece from a thermoplastic material, the article having internal and external shapes and being prepared by compression-blow moulding.

Blow moulding of hollow shaped articles to be used as dispensers of flowable materials is not new (U.S. Patent No. 3,325,860). Compression moulding of shapes, such as threads, in the neck of a blow moulded article is known (U.S. Patent No.3,311,950).

It is also known to compression mould separate members, such as closures, in the same parison used for blow moulding an article (U.S. Patent No.

3,534,435). The shaping of a parison priorto blow moulding has been shown (U.S. Patent No.

3,294,885).

Containers assembled from blow moulded and compression moulded parts, as well as from paper, foil and metal parts, have been used for dispensing flowable materials. The containers are normally shaped to have a cylindrical body with a conically shaped nozzle on one end and a plunger in the opposite end. The nozzle is opened, often by cutting, and the flowable material is pushed out of the container by the plunger.

Sealants, caulks and glues are frequently dispensed from such containers. Such containers have many advantages, particularly with respect to the uniformity of the size of the dispensed stream.

However, a major problem with such dispensers has been the hardening of the dispensed material in the nozzle between uses.

For example, one commerically available sealant dispensing cartridge is formed from an extruded tube and an injection moulded nozzle. The tube and nozzle are connected by spin welding. The user opens the conical nozzle by cutting it to the desired diameter. The sealant is squeezed out of the tube through the nozzle by operation of the plunger.

However, when the sealant is an air-or moisturecuring polymer, it can set up in then nozzle between uses due to the air or water vapour which passes through the open end of the nozzle and through the nozzle material. Hence, the nozzle becomes plugged.

The plug must be removed by digging or a passageway must be puncture through it and failing this, the unused sealant in the tube is normally lost. Similar situations occur with partially used dispensers of glue or caulk.

An attempt has been made to solve this problem by providing a cap to cover the nozzle between uses.

One commerically avaitabe sealant dispenser is furnished with a cap attached to the tube by a flexible connector and between uses, the open end of the nozzle can be covered with this cap. Hardening of the sealant due to air or moisture exposure at the open end of the nozzle is reduced. However, hardening is not stopped because of the permeability of the nozzle material and/or air or moisture leakage through the joint.

Yet another response to this problem is a commerically available sealant dispenser which comprises a fibre-foil tubular body having a flat metal end crimped into the fibrefoil. A two-piece injection moulded nozzle is crimped into the metal end at its centre. The injection moulded nozzle is conical in shape and has a female base portion which is threaded to receive the male tip portion. When the sealant sets up to form a plug in the male tip portion, the tip is unscrewed from the base for easy removal of the plug.

Such a dispenser has many advantages, but it is expensive to manufacture. The several moulding, forming and assembling steps require a great deal of individual handling, which can be both slow and expensive. Hence, the cost of manufacturing such a dispenser can be prohibitive in a highly competitive market.

We have, therefore, sought to supply a dispensing cartridge which includes a nozzle portion capable of being temporarily separated from the cartridge and a plug portion which is capable of being substituted for the nozzle portion.

We have also sought to provide a method of making such a cartridge by a method which is simpler and less expensive than prior art methods.

Accordingly we have now found a method for making a hollow, shaped article from a parison of thermoplastic material. According to this method, the parison is positioned in the cavity of a mould which has a closed end and an open end so that it is gripped near the open end by a collar portion of the mould.

An extendable blow pin means is extended into the parison at the open end of the mould cavity, and the gripped end of the parison is compressed between the collar and a mandrel portion of the blow pin means. The opposite end of the parion is compressed by an extended portion of the blow pin means. The parison conforms internally to the shape of the extended portion of the blow pin means and externally to the shape of the closed end of the mould cavity.

The parison is inflated by fluid pressure so that it assumes the shape of the mould cavity. After cooling, the article is ejected from the mould. The ejected article has an open end and a substantially closed end. The substantially closed end has internal and external compression moulded shapes which correspond to the shape of the extended portion of the extendable blow pin means and to the shape of the closed end of the mould cavity.

The apparatus for performing this method comprises a mould for receiving the plastic parison. The mould has a cavity with a closed end and an open end, the closed end of the cavity being shaped for forming one end of the outside of the parison.

The apparatus further comprises an axially movable blow pin means which has a mandrel portion and an extendable portion. The blow pin means is adapted for supplying fluid pressure to the inside of the parison.

A means for axially moving the blow pin means into the parison is also provided. The blow pin means is movable in such a way that the gripped end of the parison is compressed between the collar of the open end of the mould cavity and the mandrel portion of the blow pin means. Movement of the blow pin means also results in the opposite end of the parison being compressed by the extended portion of the blow pin means, causing the parison to conform to the shape of the extended portion on the inside and to the shape of the closed end of the mould cavity on the outside.

Means for providing fluid pressure through the blow pin means sufficient to cause the parison to assume the shape of the cavity and means for ejecting the shaped article from the mould are also included. The appartus may also include means for cooling the parison prior to ejecting the article.

The invention includes a hollow shaped article which is formed in one piece so as to have a substantially closed end and an open end with shaped formed both inside and outside the article at the closed end.

The invention is described below with reference to the accompanying drawings wherein: Figure 1 shows schematically and in cross-section one embodiment of a hollow shaped article according to the present invention having a shape suitable for use as a dispensing cartridge; Figure 2 shows schematically and in cross-section a portion of another embodiment of an article according to the invention similar to the article in Figure 1 and ready for use as a dispensing cartridge; Figure 3 shows in perspective view an apparatus for extruding a parison; Figure 4 shows schematically and in cross-section an extruded parison placed in a mould in preparation for compression blow moulding; Figure 5 shows schematically and in cross-section a detail of the mandrel portion of a blow pin assembly positioned to close the open end of a mould cavity;; Figure 6shows schematically and in cross-section one embodiment extended blow pin assembly positioned for compressing internal and external shapes in the closed end of the article; Figure 7shows schematically and in cross-section an alternative embodiment of an apparatus according to the present invention.

Figures 8a and 8b show schematically and in cross-section mould arrangements for injectionblow moulding an article according to the present invention; Figure 9 shows schematically and in cross-section a mould arrangement for injection moulding an article according to the present invention; Figure 10 shows schematically and in crosssection one embodiment of a hollow shaped article according to the present invention which is useful as a dispensing cartridge and which includes an exter nallythreaded portion suitable for plugging the internally threaded portion; and Figure 11 shows schematically and in crosssection an assembly for forming the article of Figure 10.

Referring more specifically to Figure 1, there is shown a hollow shaped cartridge 1 formed in one piece and having an open end 2 and a closed end 3.

External threads 4 and internal threads 5 are compression moulded on closed end 3, the threads 4 and 5 being sized to be matable. The cartridge 1 also includes a thin walled break-away portion 6 between internal threads 5 and external threads 4. External threads 4 disposed on a hollow tip 7 can be used to form a nozzle (such as nozzle 9 in the embodiment of Figure 2).

A thin-walled breakaway position 6 is formed so that a tip 7 can easily be broken away from cartridge 1 and threaded into it. Any easily broken connecting piece can be used in this preferred embodment as long as it can be formed as a part of the one piece article. For example, it is within the scope of the invention that the thin-walled portion 6 be omitted and that the hollow tip 7 be connected to cartridge 1 by an easily broken connecting strip or by flashing.

In such an embodiment, the hollow shaped article would have a substantially closed end even though portion 6 is not present.

The cartridge 1 can be made from any suitable material such as a thermoplastic material capable of being blow moulded or injection moulded into useful shapes. That is, the material should be plastic during shaping and relatively inflexible afterwards.

Typical of such materials are glass, polyvinylidene chloride, nylon, polyethylene glycol terephthalate, polyethylene, polypropylene, poly-1 -butene, poly-4methylpentene-1, vinyl chloride, styrene polymers and copolymers and mixtures thereof.

Polyethylene and polypropylene are preferred because of their commercial availability. Good results have been obtained using Dylan (Trade Mark).

polyethylene pellets and Dypro (Trade Mark) polypropylene pellets, both available from ARCO Polymers Inc. (Philadelphia, PA 19101).

The cartridge 1 may have any suitable shape, the particular shape shown in Figure 1 being useful for being made into a dispensing cartridge.

Referring more specifically to Figure 2, there is shown a dispensing cartridge 8 made from a cartridge similar to that shown in Figure 1.

The cartridge 8 includes a nozzle portion 9 which is threaded into cartridge body 10. The cartride 8 is first formed ina shape similar to cartridge 1 of Figure 1 and the nozzle 9 subsequently has been broken away from body 10 and threaded into it.

The nozzle 9 is shaped so that its outside diameter is graduated at shoulders 11. The graduations are a convenient guide for cutting the nozzle so as to expose a selected inside diameter.

A rupturable seal 12 shown in Figure 2 is an optional, preferred feature of the article according to the invention. The seal 12 is positioned so as to separate nozzle portion 9 and the interior of the rest of cartridge 8. The seal 12 is normally formed from a metal foil or the like.

The main part of the cartridge 8 is filled with a flowable material 13 to be dispensed. The material 13 can be any flowable material such as caulk, glue or sealant or the like.

When used, the nozzle portion 9 is cut to provide a dispensing orifice of the desired diameter. The seal 12, if present, is ruptured to allow material 13 to be squeezed through the nozzle portion 9 and applied.

The material 13 is normally squeezed from the cartridge 8 by means of a plunger (not shown).

Between uses, material 13 remaining in the nozzle portion 9 may become hard and form a plug. The plug is cleared by separating the nozzle portion 9 from the body 10, removing the plug and reconnecting the nozzle portion 9 to the body 10.

The cartridge 8 may, optionally, have a thread shape 16 compression moulded on its open end.

Thread shape 16 may be useful in mounting cartridge 8 in a holder when it is used for dispensing material 13.

Referring more specifically now to Figures 3-9, methods and apparatus for making a hollow shaped article according to the present invention are described.

Figure 3 shows one embodiment of an extrusion blow moulding head 17 suitable for forming a plastic parison 18 by extrusion of a material such as polyethylene. The parison is tubular in shape, relatively thick-walled and heated sufficiently to be plastic.

Sectional mould 19 is shown in an open position and is movable from the open position to a closed position. Such an extruder-moulded combination is known in the art as an extrusion-blow moulding assembly. Such assemblies are commercially available and can be used as a component of an apparatus according to the present invention.

Extendable blow pin assembly drive means 20 is positioned to be above the open end of the cavity of mould 19 after mould 19 has received the parison 18.

The compession-blow moulding operation is accomplished by means 20 as illustrated in Figures 4-6 and described hereinafter.

Figure 4 shows a mould 19 which has been closed around the parison 18. The mould 19 has a closed end 21 and an open end 22. Parison 18 is gripped near the open end of the mould by collar portion 23.

As is well known in the extrusion-blow moulding art, a stream of air pressure is normally applied centrally to the parison through suitable ports in the centre of the extrusion die (not shown). The air pressure causes the parison 18 to flare slightly when the mould 19 is closed. The flaring causes the parison 18 to fit the collar 23. The parison 18 is normally separated from the extruder by first drawing a hot wire, or the like, (not shown) through it and then moving mould 19 laterally so that the parison 18 is positioned under the blow pin assembly as shown in Figure 5.

Figure 5 shows an extendable blow pin assembly 24 as it is inserted into the parison 18 at the open end 22 of the mould 19. The assembly 24 compresses the gripped end of the parison 18 between itself and the collar 23.

The extended blow pin assembly 24 comprises a mandrel portion 25 and an extendable shaped portion 26. Shaped portion 26 includes ports 27 which are suitable for supplying fluid pressure (such as air pressure) for inflating the parison 18.

Figure 6 shows the assembly 24 after the mandrel 25 has been seated in the collar 23 and the shaped portion 26 has been extended by drive means 20.

The shaped portion 26 compresses a portion of the parison 18 between itself and the closed end 21 of the mould 19. Compressing force supplied by drive means 20 causes the parison 18 to take on an internal shape corresponding to the form of shaped portion 26 of assembly 24 and an external shape corresponding to the shape of closed end 21 of mould 19.

In the exemplary embodiment of Figure 6, the shapes impressed in parison 18 are threads sized to be matable. The parison 18 is inflated to conform to the shape of the cavity in the mould 19. Inflation is accomplished by the introduction of fluid pressure into the parison 18 through ports 27 in shaped portion 26.

Means 20 includes a hydraulic cylinder 30 which is activated to lower the assembly 24 until the mandrel 25 is seated in the collar 23. A cylinder 31 is then hydraulically activated to move the shaped portion 26 so that it applies a compressive force to the parison 18 which is held between the shaped portion 26 and the closed end 21 of the mould 19. In the exemplary embodiment of Figure 6, the shaped portion 26 extends concentrically through the mandrel portion 25.

After the parison has been blown to shape by fluid pressure through ports 27, the parison is cooled so that the thermoplastic material sets. The parison can be allowed to cool by the conduction of heat through the mould. However, in order to speed setting, the mould and parison are normally cooled by the passage of a cold liquid, such as water, through a cooling jacket 32.

After the parison 18 has cooled, shaped portion 26 is retracted and mandrel portion 25 is withdrawn.

Shaped portion 26 is the exemplary embodiment of Figure 6 is desirably removed without substantially disrupting the thread shapes formed on the inside of the parison 18.

This is accomplished by rotating portion 26 so that it unsrews from the threads it has formed. Rotation of portion 26 is accomplished by the operation of a hydraulic motor 35 which rotates a wheel 36. Teeth on the wheel 36 fit cogs 37 on an idler wheel 38. As the wheel 38 rotates, tabs 39 on the wheel 38 rotate against tabs 40 on a flange 41. The flange 41 is connected to the portion 26.

As the portion 26 is rotated, it unscrews from the threads it has formed and thus moves portion 26 in a retracting direction until the portion 26 clears the threads. The lengths of tabs 40 and 39 can be selected so that they disengage at about the same time portion 26 clears the threads. Hydraulic pressure to cylinder 31 is normally reduced during the unthreading operation in order to ease movement of the portion 26. The retained air pressure in the article exerts a pressure on the member 26 to aid in moving it in a disengaging direction.

Cylinders 30 and 31 can then be operated to retract the shaped portion 26 and mandrel portion 25 prior to operating clamps 28 and ejecting a hollow shaped article such as article 1 of Figure 1. It is to be understood that whenever shaped portion 26 forms other shapes in the parison 18, then the rotating prior to withdrawal may not be necessary or even desirable.

Figure 7 shows an alternative embodiment of an apparatus according to the present invention. A mould 42 grips parison 43 at a collar portion of the mould and a mandrel 45 compresses the gripped portion of parison 43 between the collar and itself so that a pattern 46 in the collar portion is compressed in the gripped portion of the parison 43.

The mandrel 45 is a flared portion of the extendable blow pin means 47. A shaped portion 48 is extendable blow pin means 47 compresses a portion of parison 43 against closed end 49 of the mould 42.

In the exemplary embodiment of Figure 7, a shaped portion 48 impresses a roughened pattern in parison 43 on the inside of its closed end. The outside of the closed end of the parison assumes the shape of closed end 49 of the mould 42.

Movement of the extendable blow pin means into the mould is accomplished by the operation of a cylinder 50.

Fluid pressure (such as air pressure) to inflate parison 43 is supplied through a tube 53 and a channel (not shown) which opens at ports 54 on means 47.

In operation the parison 43 is gripped in the mould 42 much as parison 18 is gripped in mould 19 in the embodiment of Figure 5. Cylinder 50 moves means 47 into the parison while fluid pressure is supplied through tube 53 and ports 54. As mandrel 45 and end portion 48 seat against parison 43, the fluid pressure inflates the parison so that it assumes the shape of the cavity of mould 42. Pressure from cylinder 50 compresses the shapes at shaped end 48 and at 46 into the parison. After the blow moulded shape is allowed to cool and is no longer plastic, means 47 is retracted and clamps 55 are released to eject the article from the mould.

Figures 8a and 8b show that an article according to the present invention can be made by well known injection-blow moulding techniques.

A mandrel 56 is placed in the cavity of an injection mould 57 which is securely fastened with clamps 58.

The mandrel 56 is connected to a fluid pressure source (not shown) through a flexible connector 59.

Channels (not shown) in the mandrel 56 connect flexible connector 59 with valve ports 60.

Injection mould 57 is connected to a supply of thermoplastic material under pressure (not shown) by connector 61.

Plastic material under pressure is injected into the cavity between injection mould 57 and mandrel 56 to form parison 62 and injection moulded shape 63 at one end of the parison 62. A shape 63 is formed when the plastic material is injected between shaped portion 66 of the inside of mould 57 and shaped portion 67 of the mandrel 56. In the embodiment of Figures 8a and 8b, shape 63 comprises matable male and female threads with a thin-walled breakaway portion therebetween.

After the parison 62 and shape 63 are formed, clamps 58 are released. The mandrel 56, holding the parison, is transferred to a blow mould 64 which has a shaped tip portion 65 which is substantially identical in shape to shaped portion 66 of the injection mould 57. The shape 63 fits between the shaped tip portion 65 of the blow mould 64 and the shaped tip portion 67 of the mandrel 56.

The mould 64 is sealed with clamps 68 and fluid pressure is provided through a flexible connector 59 and valve ports 60. The fluid pressure inflates the parison 62 is cooled by the action of cooling veins 76 to form a shaped article formed in one piece having a closed end and an open end with shapes formed both inside and outside the article at the closed end.

Figure 9 illustrates an apparatus which shows that an article according to the present invention can be formed by well known injection moulding techniques.

A mandrel 70 is positioned inside a mould 71 so that there is a cavity therebetween. The mould 71 and the mandrel 70 are shaped at one end so that the cavity defines a hollow tip section 72 with matable male and female threads.

The mould 71 is connected by connector means 73 to a source (not shown) of plastic material under pressure. The plastic material is injected into the cavity between the mould 71 and the mandrel 70 to take on the shape of the cavity.

After injection and cooling, the mould 71 is opened by releasing clamps 74 to expose the mandrel 70 covered with an article 75 which can be unscrewed from mandrel 70. The unscrewing action removes article 75 from the thread shapes on mandrel 70 without stripping the corresponding thread shapes in the article. Article 75 is formed one piece and has an open end and a closed end with shapes formed both on the inside and outside of the closed end.

Referring more specifically to Figure 10, there is shown a portion of a hollow shaped article 80 formed in one piece which has an open end (not shown) such as end 2 of Figure 1. The closed end of article 80 is shown in Figure 10. The closed end includes internal threads 81 and external threads 82 the latter being disposed on hollow tip 83. The internal and external threads are shaped to be matable.

The closed end further includes a plug 84 connected to hollow tip 83. Plug 84 has external threads 85 which are shaped to be matable with internal threads 81.

The article 80 is useful as a dispensing cartridge.

The hollow tip 83 can be separated from the body 86 and reattached by screwing external threads 82 into internal threads 81. When the plug 84 is separated from the hollow 83, the article is useful as a dispensing cartridge in a manner similar to that described in connection with the cartridge 8 of Figure 2.

The material to be dispensed may become hard and form a plug in the hollow tip 83 during long periods between use. In the embodiment of Figure 10, this problem can be avoided by removing the hollow tip 83 and screwing in the plug 84. The hollow tip 83 may then be kept clear until subsequent use.

Referring more specifically to Figure 11, there is shown a portion of an assembly for making the article 80 of Figure 10. The article 80 can in general, be made using an apparatus and method similar to those described in connection with Figures 4-6.

Parison 87 is placed in sectional mould 88 and held in position between the mould collar (not shown) and the mandrel portion (not shown) of an extendable blow pin means. Extendable portion 89 of the extendable blow pin means is moved to compress parison 87 at the closed end of mould 88.

The closed end 90 of the mould 88 is adapted to shape the parison 87 into a plug, such as plug 84 of Figure 10. The mechanism of filling the closed end 90 with parison 87 so that is assumes the shape of the end 90 is not critical to the invention and may vary from apparatus to apparatus depending on the shape of the article.

For example, the plug may be blow moulded by fluid pressure supplied through ports (not shown) in the end of portion 89. The plug could also be blow moulded by the compressive force of ambient gas which is pushed ahead of portion 89 as it enters a narrow portion of mould 88, such as portion 91.

Alternatively, the plug could be solid and formed by compressive force as the parison is pushed into end 90 by portion 89.

Claims (21)

1. A method for making a hollow, shaped article from a parison of thermoplastic material, the method comprising: (a) positioning the parison in the cavity of a mould having a closed end and an open end so that the parison is gripped near the open end by a collar portion of the mould; (b) inserting an extendable blow pin means into the parison at the open end of the mould cavity so that the gripped end of the parion is compressed between the collar portion and a mandrel portion of the extendable blow pin means and so that the opposite end of the parison is compressed by an extended portion of the extendable blow pin means sufficiently that the parison conforms internally to the shape of the extended portion of the extendable blow pin means and externally to the shape of the closed end of the mould cavity;; (c) inflating the parison by fluid pressure so that it assumes the shape of the mould cavity; (d) allowing the parison to cool at least to a temperature at which it is substantially self supporting; and (e) ejecting the article from the mould; whereby a shaped article is produced which has an open end and a substantially closed end, the closed end having internal and external shapes which correspond to the shape of the extended portion of the extendable blow pin means and to the shape of the closed end of the mould cavity.

2. A method according to claim 1, wherein the shapes of the closed end of the article include internal and external threads, sized to be matable, disposed on a hollow tip.

3. A method according to claim 2, wherein the shapes of the closed end of the article are connected by a breakable connecting piece between the internal threads and the external threads to facilitate separation of the tip therebetween.

4. A method according to claim 2, wherein the shapes of the closed end of the article include a plug connected to the hollow tip, the plug being externally threaded to be matable with the internal threads.

5. A method according to claim 2, which includes the subsequent step of separating the portion of the tip which includes external threads and reconnecting the separated portion of the tip to the article by screwing the external threads on the separated tip portion into the mating internal threads.

6. A method according to claim 2, which includes the additional step of sealing the hollow tip to separate it from the interior of the hollow article, by means of a rupturable seal.

7. A method according to any of claims 1 to 6, wherein at least one of the collar and the mandrel portion of the extendable blow pin means is shaped so that a corresponding shape is compression moulded at the open end of the article.

8. A method according to any of claims 1 to 7, wherein the extendable blow pin means is an elongated member which is adapted to supply fluid pressure in the inside of the parison.

9. A method according to any of claims 1 to 7, wherein the extendable blow pin means is an assembly comprising a mandrel componentfor opposing the collar portion and an elongaged component disposed substantially concentric to the mandrel portion and adapted for axial extension to accomplish moulding of the parison at the closed end of the mould.

10. A method according to any of claims 1 to 7, wherein the extended portion of the extendable blow pin means is shaped so as to mould threads on the inner surface of the hollow article and wherein the method includes the additional step, prior to the step of ejecting, of removing the blow pin from engaging contact with the article by rotating the blow pin means and allowing the moulded threads to move the pin axially.

11. A method according to any of claims 1 to 10, wherein the thermoplastic parison is formed from a material comprising molten glass, polyvinylidene chloride, nylon, polyethylene glycol terephthalate, polyethylene, polypropylene, poly-1 -butene, poly-4- methylpentene-1, vinyl chloride, styrene polymers, and copolymers and mixtures thereof.

12. A method for making a hollow, shaped article from a parison of thermoplastic material substantially as herein described with reference to any of the accompanying Figures.

13. An apparatus for forming a hollow, shaped article from a parison of thermoplastic material, the apparatus comprising: (a) a mould for receiving the parison, the mould having cavity, an open end adapted to include a collar adapted to grip the parison and a closed end shape for moulding one end of the outside of the parison; (b) an axially movable blow pin means having a mandrel portion and an extendable portion, and being adapted for supply fluid pressure to the inside of the parison;; (c) means for axially moving the blow pin means into the parison at the open end of the mould so that the gripped end of the parison is compressed between the collar and the mandrel portion of the blow pin means and so that the opposite end of the parison is compressed by the extendable portion of the blow pin means sufficiently that it conforms to the shape of the extendable portion of the blow pin means and to the internal shape of the closed end of the mould; (d) supply means for providing fluid pressure to the inside of the parison through the blow pin means, the pressure being sufficient to inflate the parison so that it assumes the shape of the mould cavity; and (e) means for ejecting the shaped article from the mould.

14. An apparatus according to claim 12, wherein the extendable portion of the blow pin means and the shaped, closed end of the mould cavity are adapted to produce internal and external threads, sized to be matable, disposed on a hollow tip of the article.

15. An apparatus according to claim 14, wherein the extendable portion of the blow pin assembly and the shaped, closed end of the mould cavity are further adapted to provide a breakable connecting piece between the internal threads and the external threads to facilitate separation of the tip therebetween.

16. An apparatus according to claim 14, wherein the closed end of the mould cavity is adapted to produce a plug connected to the hollow tip, and plug being externally threaded to be matable with the internal threads.

17. An apparatus according to claim 13 wherein at least one of the collar and the mandrel portions of the blow pin means is patterned so that a corresponding shape is compression moulded at the open end of the article.

18. An apparatus according to claim 13 wherein the axially moveable blow pin means is an assembly comprising a mandrel component for opposing the collar and an extendable blow pin component disposed substantially concentrically to the mandrel component and adapted for axial extension to accomplish moulding of shapes at the closed end of the mould.

19. An apparatus according to claim 13, wherein the extendable portion of the blow pin means is designed to impress threads on the inside of the article and wherein the blow pin means is adapted for rotation after the threads have been impressed so that the threads axially move the pin out of engaging contact with the article.

20. An apparatus according to any of claims 13 to 19, which includes a means for cooling a blown thermoplastic parison.

21. An apparatusforforming a hollow, shaped article from a parison of thermoplastic material substantially as herein described with reference to the accompanying Figures.