GB2039463A - Moulding machine - Google Patents

Abstract

An injection moulding machine especially for moulding shoe components is provided with a mould-assembly clamp means 62 for conveying an assembly 10 between stations of the machine and mould-assembly opening means at a loading/unloading station 16 comprising a mechanism 72 which lifts a top part 22 of the assembly off a bottom part 20, inverts it and places it alongside the bottom part so that an operator is presented with the two parts 20, 22 face-upwardly and side-by-side thus giving ready access for the removal of moulded articles and placements of inserts for subsequent moulding operations. <IMAGE>

Description

SPECIFICATION Sole moulding machine This invention is concerned with injection moulding machines especially shoe component moulding machines e.g. shoe sole moulding machines suitable for use in moulding shoe sole units, including units consisting of a combined sole portion and heel portion. The term "shoe" is used herein generically to indicate outer footwear generally, whether ready for wear or in the course of manufacture.

Shoe sole moulding machines are known for moulding shoe sole units. Known shoe sole moulding machines comprise a mould assembly comprising two mould parts each having a parting face, portions of the parting faces being arranged to abut one another when the mould assembly is in a closed condition to form a mould cavity (or cavities). In the manufacture of shoe sole units moulding material is introduced into the mould cavity and the moulding material allowed to solidify with the mould assembly in the closed condition so that the material adopts the shape of the mould cavity. The mould parts are then moved apart to an open condition in which the solidified sole unit can be removed from the mould assembly.In many styles of shoe it is necessary to incorporate inserts in the sole unit as it is manufactured, for example leather tread pieces, attractively coloured heel coverings, imitation welt strips or the like. These are commonly positioned on the mould parts whilst the mould assembly is in the open condition, the mould parts are moved so that the assembly is put in the closed condition and moulding material injected into the mould cavity to fill the cavity and allowed to solidify as hereinbefore mentioned. The heretofore known shoe sole moulding machines have not been altogether satisfactory in that access to the parting faces of the mould assembly when in the open condition has been restricted thus impeding removal of a moulded unit from the mould assembly and also impeding the positioning of inserts on the mould parts.This restriction of access hinders the operator and thus slows production or causes undue operator fatigue. In some known shoe sole moulding machines in which the mould assembly clamp used to clamp the mould parts together during injection has also been used to open the mould parts, the presence of the mould clamping mechanism necessary to apply the high clamping force severely restricts access to the moulds; furthermore such machines as well as giving very restricted access between the mould parting faces are also expensive in that a mould clamping mechanism is necessary for each mould assembly and this mechanism must have a sufficient stroke to move the mould parts sufficiently far apart to give access at least enough to remove the mouldings.

Such machines, therefore, as well as giving poor access are also expensive.

It is an object of the invention to provide an injection moulding machine e.g. a shoe sole moulding machine in which the parting faces of the mould assembly are more readily accessible when the mould assembly is in the open condition, than in some heretofore known machines.

An injection moulding machine in accordance with the invention comprises upper and lower presser members at an injection station, means for opening and closing the presser members, mould-assembly conveyor means for conveying a mould assembly comprising two mould parts each having a parting face (the parting faces abutting one another when the mould-assembly is in a closed condition) between the stations of the machine, and mouldassembly opening means for opening and closing the mould assembly at a loading and unloading station, the mould assembly opening means comprising a mechanism which lifts a first part of the mould assembly off a second part, inverts it and places it alongside the second part so that the operator is presented with the two parts face-upwardly and side-by-side ready for removal of the moulded article, e.g. a shoe sole unit, or articles.

A preferred machine in accordance with the invention comprises two loading and unloading stations with the injection station disposed between the two loading and unloading stations. Suitably such a machine comprises two mould assemblies mounted for movement by mould-assembly conveying means between the stations so that when one of the mould assemblies is in the injection station the other is at its associated loading and unloading station, and vice versa. Preferably the mould assembly conveying means comprises a carriage which is movable along a linear path to move the mould-assemblies between the injection station and the loading and unloading stations.

Preferably the mechanism of the mould-assembly opening means by which the first part of the mouldassembly is inverted after it has been lifted off the second part inverts the first part by a pivotal movement. Conveniently the mechanism comprises a mould opening member by which the first part of the mould-assembly is carried at the loading and unloading station, the mould opening member being pivotally mounted. Suitably the mould opening member is pivoted to a member which is moved linearly by the power unit of the mechanism to lift the first part of the mould-assembly off the second part. Suitably the first part of the mould-assembly is slidingly received in the mould-opening member at the loading and unloading station.

Preferably the mould-assembly opening means of a machine in accordance with the invention is mounted at the loading and unloading station; however the mould-assembly opening means may be mounted on the mould-assembly conveying means so that as the mould-assembly is conveyed between the stations the associated mould-assembly opening means travels with the mould-assembly, e.g. the mould-assembly opening means may be mounted on the carriage of the preferred machine hereinbefore mentioned.

Where the first part of the mould-assembly is inverted by pivotal movement, the pivotal movement preferably takes place about an axis extending towards and away from the operator at the loading and unloading station, the axis, where the mouldassemblies are conveyed along a linear path suitably lying in a plane parallel with the path of the mouldassembly conveying means. Preferably this axis is horizontal but the axis may be inclined slightly upwardly away from the operator from the horizontal by a small amount, not exceeding at a maximum 300 to the horizontal.

The mould-assemblies of machines in accordance with the invention comprise two parts; however each of these parts may be made up of one or more components; for example ejector pins may be mounted on one of the mould parts.

Whereas the illustrative machine described hereinafter is powered by hydraulic means other forms of power may be used in machines in accordance with the invention, for example electric motors or air operated piston and cylinder units and the means for opening and closing the presser members may comprise a suitable toggle or other mechanical linkage.

Whereas the illustrative machine described hereinafter as an injection unit the nozzle of which is applied to the mould, a machine otherwise similar to the illustrative machine, in accordance with the invention, may comprise a hot runner system.

There now follows a detailed description to be read with reference to the accompanying drawings of a shoe sole moulding machine embodying the invention. It will be realised that this machine has been selected for description to illustrate the invention by way of example and not by way of limitation of the invention.

In the accompanying drawings:~ Figure 1 is a perspective view of the illustrative shoe sole moulding machine; Figure 2 is a front view of the illustrative machine; and Figure 3 is a side view of the illustrative machine taken from the direction of the arrow lil on Figure 2.

The illustrative shoe sole moulding machine comprises two mould assemblies 10, 12. The illustrative machine has a single injection station 14 and two loadinglunloading stations 16,18, one at either side of the injection station 14. Each of the mould assemblies comprises two mould parts each comprising a parting face, portions of parting faces abutting one another when the mould assembly is in a closed condition.

The two mould assemblies 10, 12 are generally similar and the mould assembly 10 will be described hereinafter for convenience. The mould assembly 10 comprises a first, top mould part 22 and a second, bottom mould part 20; the mould assembly 10 is shown in the drawings with the mould parts 20, 22 in an open condition. The mould assembly 12 is shown in a closed condition in the drawings. The bottom mould part 20 comprises a parting face 24 in which are formed a pair of recesses 26 providing moulding surfaces of the bottom mould part. The upper mould part 22 comprises a parting face 28 and a pair of moulding surfaces 30 which, when the mould assembly is in the closed condition co-operate with the recesses 26 of the bottom mould part to form a mould cavity.The mould cavity of the mould assembly 10 is intended to form a sole and heel unit having a sole portion and a heel portion.

An injection port 29 is provided at a rear face of the bottom mould part and passages 31 lead from the port 29 into the recesses 26. Location holes 27 are provided in the parting face 24 of the bottom mould part 20 and location pegs 33 project from the parting face 28 of the top mould part 22, the pegs 33 being received in the holes 27 when the assembly 10 is in the closed position to accurately locate the parts 20, 22 relative to one another.

At the injection station are disposed an injection unit 32 and a mould assembly clamp 34. The mould assembly clamp 34 comprises an upper frame member 36 connected to a main frame of the illustrative machine 38 bytie rods 40. A cylinder 42 of a piston and cylinder unit is mounted on the frame member 36 with a piston rod 44 of the unit projecting downwardly through a hole (not shown) in the frame member 36. A presser plate 46 is mounted at a lower end portion of the piston rod 44 and provides an upper presser member of the illustrative machine.

The injection unit 32 is mounted on the frame member 38 and is of the reciprocating screw type (however for some applications other types of injection unit may be used for example a screw extruder type which injects material solely by rotation of the screw). The injection unit 32 comprises a barrel portion 48 in which a screw is mounted for rotation and sliding movement; the barrel portion 48 is supported by a block 50 on which is mounted a hopper 52 through which plastics material to be injected is supplied into the barrel portion for working by the screw.The block is mounted for sliding movement by a piston and cylinder unit 54 on rails 56 mounted on the frame 38 to move an injection nozzle (not shown) of the injection unit into and out of engagement with the port 29 of one of the mould assemblies 10. 12 when it is at the injection station. The injection unit 32 also comprises a motor 58 by which an input shaft 60 of the injection screw may be rotated to rotate the screw and thereby plasticise plastics material supplied into the barrel 48 from the hopper 52. The motor 58 is also slidably mounted on the rails 56 and may be moved therealong by means (not shown) to cause the screw to slide in the barrel thus to cause ejection of plasticised plastics material from the barrel 48 through the nozzle portion.

The illustrative machine comprises mould assembly conveying means comprising a carriage 62 slidable on rails (not shown) supported by the frame 38 transversely across the illustrative machine. The car riage 62 is moved to and fro along the rails by a piston and cylinder unit comprising a cylinder 64 secured to the frame having a piston rod 66 con nected to the carriage 62.

In the drawings the carriage 62 is shown in a right hand position in which the mould assembly 10 is at its unloading station 16 and the mould assembly 12 is at the injection station 14 in the closed condition.

The mould assembly 12 is thus disposed between the presser plate 46 and the carriage 62, the carriage providing a lower presser member at the injection station. The bottom mould parts 20 of the mould assemblies 10, 12 are mounted on the carriage 62 by means (not shown) which clamp the bottom mould parts firmly in location on the carriage but which permit ready removal of the bottom mould parts 20 when it is necessary to change mould assemblies of the illustrative machine.

The illustrative machine further comprises mould-assembly opening means for opening and closing the mould assembly, one such opening means being disposed at the loading and unloading station 16 and another such means being disposed at the loading and unloading station 18. The mould assembly opening means are mirror images of one another and thus for convenience only the opening means at the right hand loading and unloading station 16 will be described hereinafter.This mould opening means comprises mechanism which lifts the first, top part of the mould assembly 10 off the second, bottom part 20 ofthe mould assembly 10, inverts it, and places it alongside the bottom part 20 so that an operator standing in front of the machine at the loading and unloading station 16 is presented with the two parts 20, 22 face-upwardly and sideby-side with the top mould part 22 to the right of the bottom mould part 20. At the station 18 the top mould part 22 would be positioned to the left of the bottom part 20 when the mould assembly 12 is in its open condition.

The mechanism of the mould opening means at the station 16 comprises a pillar 68 mounted in bearings (not shown) supported by the frame 38, for vertical sliding movement. The pillar 68 may be slid up and down in the bearings by operation of a hydraulic piston and cylinder unit 70 mounted on the frame 38.

The pillar 68 projects upwardly through an aperture in the frame 38 just beyond the right hand end of the carriage 62 when the carriage 62 is in its right hand position (see Figures 1 and 2). A mould opening member 72 is fulcrum med to an upper end portion of the pillar 68 by means of axle pins 74 extending through lugs 76 of the member 72 and into the upper end portion of the pillar 68. A rotary hydraulic motor 78 is mounted on the pillar and may be operated to rotate the mould opening member 72 through an angle of 180 fulcrummed about the pins 74 between a closed position and an open position in which the member 72 is shown in the drawings. When the member 72 is in its open position it rests against a stop member 80 carried by the frame 38.The mould opening member 72 is thus mounted for pivotal movement about an axis extending fore and aft of the illustrative machine towards and away from an operator at the unloading station, this axis being horizontal and perpendicular to the path of travel of the carriage 62 and generally parallel with the mould parting faces 24, 28 (however although the mould assemblies 10, 12 of the illustrative machine are shown to be planar, mould parting faces may have a slight degree of curvature depending on the style of shoe component to be moulded).

The mould opening member 72 has an undercut slideway 82 (T-shaped in cross section in the illustrative machine) in which a corresponding T-shaped projection 84 of the top mould part (projecting from the face opposite the parting face 28) is slidingly received. The slideway 82 is perpendicular to the axis provided by the pins 74. The top mould part 22 is positioned on the mould opening member 72 when the member72 is in its open position as shown in the accompanying drawings by sliding the projection 84 into the T-shaped slideway until the top mould member 22 meets location stops (not shown) by which the part 22 is located on the member 72.

The illustrative machine further comprises a guard 86 by which the operative parts of the illustrative machine are enclosed to prevent access to operative parts of the illustrative machine during its operation.

Various portions of the guard 86 are removable to give access to those parts of the illustrative machine to which access is necessary, e.g. in order to replace the top mould parts, and these removable portions have an interlock system whereby the illustrative machine is immobilised should the guard be removed to obtain access. The guard further comprises two door portions 88 (hinged in the illustrative machine but these may be slidable) by means of which, when the door portions 88 are open, access may be gained by the operator to a mould assembly at the unloading stations 16, 18. The door portions 88 are automatically locked during movement of the carriage 62 and of the mould assembly opening means but unlocked when the mould assembly opening means has positioned the assembly in its open condition so that access may be obtained to the moulding surfaces 26, 30 of the assembly.

In the operation of the illustrative machine, as can be seen from the drawings, one of the mould assemblies is at the injection station and the other is at its appropriate loading/unloading station depending on the position of the carriage 62. When the carriage 62 is in its right hand position as shown in the drawings the mould assembly 10 is atthe loading station 16 and the mould assembly 12 is at the injection station; when the carriage 62 is in its left hand position the mould assembly 12 is carried to the loading station 18 and the mould assembly 10 is carried to the injection station.The mould assemblies 10, 12 are mounted in the illustrative machine when the carriage 62 is in a position for receiving a mould assembly at its appropriate loading/unloading station 16,18, the bottom mould part 20 being positioned on the carriage and the top mould part 22 being slidingly received on the mould opening member 72 when it is in its open position as hereinbefore described. Assuming that the mould assemblies 10, 12 are mounted in the illustrative machine and that the carriage 62 is in its right hand position with the mould assembly 10 in its open condition as shown in the accompanying drawings, a cycle of operation of the illustrative machine will be hereinafter described. The operator of the illustrative machine standing in front of the machine at the loading station 16 with the door portion 88 open as shown in the drawings first positions any insert on the moulding surfaces 26, 30 of the mould parts 20, 22, for example he may position a tread insert on the moulding surface 26 and a rand insert on the mould ing surface 30 for incorporation in the finished sole unit; the moulding surfaces 26,30 are of course designed to accommodate the inserts to be incorporated. Alternatively, the units being moulded may not require inserts in which case the operator does not need to position them.Having positioned the inserts the operator closes the door portion 28 and actuates a two-handed trip (a further safety device) which first of all locks the door portions 88 in their closed positions; if one of the door portions is open or the lock fails to operate for some reason the machine cycle will not proceed further. Assuming that operation of the two-handed trip causes the door portions 88 to be locked satisfactorily the rotary hydraulic motor 78 is actuated to rotate the mould opening members 72 through 1800 about the axle pins 74 (counter-clockwise viewing Figures 1 and 2 of the drawings) to carry the top mould part 22 to a position above and in alignment with the bottom mould part 20 but spaced above the bottom mould part 20.When the member 72 has carried the top part 22 to this position in alignment with the bottom part 20 the piston and cylinder unit 70 is caused to operate to lower the pillar 68 thus to lower the top mould part 22 vertically towards the bottom mould part 20 until the parting faces 24,28 firmly engage one another at which point downward movement of the pillar 68 by the unit 70 ceases, the parting faces 24,28 abutting one another.

Next hydraulic fluid is admitted to the cylinder 64 to draw the piston rod 66 leftwardly (viewing Figure 2) to move the carriage 62 from the right hand position in which it is shown in the drawings to its left hand position, the presser plate 46 of the mould assembly clamp being at this time held in a raised position by operation of the cylinder 42 (the mould assembly clamp 34 thus being in an open condition).

When the member 72 is in its closed position with the mould assembly 10 in its closed position the slideway 82 is parallel with the path of movement of the carriage 68, as is the T-shaped projection 84 from the top mould member 22. Thus, when the cylinder 64 operates to slide the carriage 62 leftwardly the projection 84 slides along the slideway (the top mould part 22 moving with the bottom part 20 by virtue of the engagement of the pegs 33 in the holes 27) out of the slideway 82, the closed mould assembly being carried on the carriage into position in the injection station. When the carriage 62 reaches its left hand position the closed mould assembly 10 is in the injection station occupying the position in which the assembly 12 is shown in the drawings.Upon reaching its left hand position the carriage 62 initiates introduction of hydraulic fluid to the cylinder 64 to cause the pressed plate 46 to be lowered towards an upper face of the top mould part 22 (the projection 84 being accommodated in a recess in the plate 46) until the presser plate 46 firmly engages the top part 22, the mould assembly 10 thus being firmly clamped between the presser plate 46 and the car riage 62. Clamping of the mould assembly 10 at the injection station initiates operation of the injection unit 32, the barrel 48 being moved forwardly alone the rails 56 until the nozzle portion (not shown) engages in the port 29 of the mould assembly 10.

Engagement of the nozzle portion in the port initiates injection movement of the screw relative to the barrel causing plastics material to be injected from the barrel 48 through the port 29 and passages 31 into the mould cavities of the mould assembly 10. The nozzle portion remains in engagement with the mould assembly 10 for a period during which the injected plastics material in the mould cavity cools sufficiently to permit withdrawal of the nozzle portion. To aid cooling of the injected material a coolant system (not shown) may be provided to cool the mould assembly either directly, or indirectly by cooling the presser plate 46 and the carriage 62.During injection and cooling of the injected material in the mould assembly 10 the operator has meanwhile moved to the loading station 18, opened the door portion 88 (which unlocks after movement of the carriage 62 and opening movement of the mould opening member 72 has ceased) and unloads the moulded units from the mould assembly 12 which at this time will be at the loading station 18 with its top mould part 22 to the left hand of its bottom part 20 viewed by the operator.After removing the previously moulded sole units from the assembly 12 the operator loads the moulding surfaces of the assembly 12 with any inserts required as hereinbefore described in relation to the assembly 10, closes the door portion 88 at the station 18 and operates the two handed trip as hereinbefore described in relation to the station 16, to cause the assembly 12 to be moved to its closed condition and the carriage 62 to move from its left hand position back to the right hand position in which it is shown in the drawings.

Operation of the two handed trip causes hydraulic fluid to be admitted to the cylinder 42 to move the presser plate 46 to its raised position thus opening the mould assembly clamp. The illustrative machine includes a timer which prevents opening of the clamp 34 and movement of the carriage 62 until sufficient cooling time for the injected material has elapsed to enable the material to reach a sufficiently solidified condition; usually, however, the timer will have tripped before the operator has completed the loading of inserts into the mould assembly 12. After completion of injection the screw of the injection unit 32 continues to rotate under the power of the motor 58 to draw solid plastics material e.g. in granular form from the hopper 52 into the barrel 48 to plasticise the material for the next injection shot, in known manner. As the carriage 62 slides back towards its right hand position, carrying the closed mould assembly 10 from the injection station, the T-shaped projection from the top mould part 22 slides into the slideway 84.

When the carriage 62 has returned to its right hand position the piston and cylinder unit 70 is actuated to raise the pillar 68 by a predetermined distance, thereby vertically raising the mould opening member 72, carrying with the member 72 the top mould part by virtue of engagement of the T-shaped projection in the T-shaped slideway 82. The pillar 68 is raised by the unit 70 sufficiently to raise the top mould part 22 away from the bottom part 20 by a sufficient distance that when the mould opening member 72 is pivoted about the pins 74 the moulded sole unit will not be trapped between the two mould parts and thereby damaged.After the unit 70 has raised the member 72 to its upper position, the rotary hydraulic motor 78 is actuated to swing the mould opening member72 about the pins 74 clockwise (viewing Figures 1 and 2) through 180 until it engages the stop member 80, carrying with it the top mould part 22, back to the position in which the mould assembly 10 is shown in Figures 1 and 2 of the drawings. The operator may then open the door portion 88 of the station 16 and the operator is presented with the two mould parts face-upwardly and side-by-side ready for removal of the moulded sole units from the mould assembly and the placement of inserts for the next moulding operation as hereinbefore described.

As the mould parts are presented side-by-side to the operator at the loading stations 16, 18 access to the moulding surface of either of the mould parts, for example to place inserts on the moulding surfaces, is simple, the opening and closing of the mould parts in the manner of a book as hereinbefore described, in front of the operator, facilitating this ready access in the illustrative machine. As hereinbefore mentioned the vertical movement of the top mould part 22 relative to the bottom mould part 20 to lift the top part 22 clear before any pivotal movement takes place ensures that the parts 20, 22 are sufficiently far apart to avoid damaging of the moulded unit when pivoted movement of the mould parts takes place.

The cylinder 42 of the mould assembly clamp 34 is designed to exert high clamping pressures on the mould assembly at the injection station to resist the injection pressures. However, it is only necessary that the piston in the cylinder 42 has a short stroke (just sufficient to lift the presser plate 46 clear of the top mould part), avoiding the long stroke which would be necessary were the same cylinder to be used both for clamping pressure and opening the mould assembly. This assists in keeping the cycle time to a minimum as well as keeping the cost of the high pressure cylinder 42 comparatively low.

In a machine in accordance with the invention generally similar to the illustrative machine it may be necessary when moulding different units to accommodate mould assemblies of various differentthicknesses. In such a machine means may be provided to adjust the heightwise position of the pins 74 on the pillar 68 (thus changing the position of the pins relative to the frame when the pillar is in its top and bottom positions but not changing the spacing of the pins between the top and bottom positions) and to adjust the position of the presser plate 46 along the piston rod 44 to ensure that there is sufficient clearance when the plate 46 is in its raised position to receive the mould assemblies but at the same time ensuring that the stroke necessary to apply clamping pressure to the mould assemblies is maintained at a minimum.

Whereas in the illustrative machine each mould assembly comprises two mould cavities, it will be appreciated that mould assemblies for use in the illustrative machine may have a single mould cavity or more than two cavities according to the size of the shoe components to be moulded. The illustrative machine is primarily intended for moulding sole and heel units but may be used for moulding other components, for example Louis sole units or heels for separate attachment to a shoe. The illustrative machine may inject any suitable moulding material, for example pvc sole moulding compound, sole moulding material known as thermoplastic rubber, and the like.

The illustrative machine is so designed that the operator does not have to reach into the high pressure clamping region of the mould assembly clamp 34 (and indeed cannot reach into this area without removing the guard 86 (which would render the machine inoperative). The pressures applied by the mould assembly opening means are so low that injury to an operator if a part of the limb is trapped in unlikely (and in any event with the guard 86 correctly positioned access to the operative parts of the machine should be impossible whilst the machine is in operation).

Claims (9)

1. An injection moulding machine comprising upper and lower presser members at an injection station, means for opening and closing the presser members, mould-assembly conveying means for conveying a mould assembly comprising two mould parts each having a parting face (the parting faces abutting one another when the mould assembly is in a closed condition) between stations of the machine, and mould-assembly opening means for opening and closing the mould assembly at a loading and unloading station, the mould-assembly opening means comprising mechanism which lifts a first part of the mould assembly off a second part, inverts it and places it alongside the second part so that the operator is presented with the two parts faceupwardly and side-by-side ready for removal of a moulded article or articles.

2. An injection moulding machine according to claim 1 in which the mechanism of the mould assembly opening means comprises a member mounted for pivotal movement to invert the first part of the mould assembly after it has been lifted away from the second part of the mould assembly.

3. A machine according to claim 2 wherein the member is mounted for pivotal movement about a horizontal or substantially horizontal axis extending towards and away from the operator at the loading and unloading station.

4. A machine according to any one of the preceding claims in which the mould assembly conveying means comprises a carriage mounted for movement along a linear path to carry the mould assembly between the injection station and the loading and unloading station.

5. A machine according to claim 4 when tied to either one of claims 2 and 3 wherein the axis about which the member is pivoted is at right angles to the path of the conveying means.

6. A machine according to either one of claims 2 and 3 comprising a piston and cylinder unit by which a pillar to which the mould opening member is pivoted, is moved to lift the first part of the mould assembly off the second part.

7. A machine according to any one of claims 2,3 and 6 wherein t# e mould opening member comprises an undercut slideway in which a corresponding projection from the first part of the mould assembly is received at the loading and unloading station.

8. A machine according to any one of claims 1 to 7 comprising two loading and unloading stations with the injection station disposed between the load- ing and unloading stations, the carriage accommodating two mould assemblies one of which is at the injection station when the other is at its loading and unloading station.

9. A machine constructed, arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.