GB2139943A - Injection mould for footwear soles - Google Patents

Abstract

A mould for moulding two or more footwear soles comprises a bottom mould 25, an intermediate mould 27 closing the bottom mould 25 to define a first mould cavity 29, and a top mould 16 which closes on the intermediate mould 22 to define a second mould cavity 33. The intermediate mould 27 has an injection port 35 for introducing mouldable plastics material into the mould cavities 29,33. <IMAGE>

Description

SPECIFICATION Mould for footwear soles This invention relates to a mould, and in particularto a footwear sole mould.

Various machines have been designed for the mass production of soles for footwear. Most such machines are somewhat complicated and cumbersome. There exists a need for a simple, yet effective machine for making footwear soles.

The object of the present invention is to meet such a need at least partially by providing a relatively simple mould for moulding a plurality of soles simultaneously.

Accordingly, the present invention provides a mould for moulding a plurality of footwear soles, comprising a bottom mould; an intermediate mould for closing on said bottom mould to define at least one first mould cavity with said bottom mould; a top mould for closing on said intermediate mould to define at least one second mould cavity with said intermediate mould; and an injection portion in said intermediate mould for introducing mouldable plastics material into said first and second cavities for forming said soles.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, and wherein: Figure 1 is a side elevation view of a footwear sole moulding machine incorporating a mould in accordance with the present invention.

Figures 2 and 3 are side elevation views of the front or mould end of the machine of Figure 1 showing the mould in the closed and open positions, respectively; Figure 4 is a perspective view from above of the mould of the present invention in the open position at the end of a moulding operation; and Figure 5 is a cross-sectional view of the mould of Figure 4, taken generally along line V-V of Figure 4, with the mould in the closed position.

With reference to the drawings, the mould of the present invention generally indicated at 1 is intended for use in a moulding machine of the type including a rectangular frame 2, with adjustable feet 3. A carriage 4 at one end of the frame 2 supports an extruder 5, which is used to inject thermoplastic material e.g. polyvinyl chloride or thermoplastic rubber into the mould 1 for forming footwear soles 6 (Figure 4). The plastics material is fed into the extruder 5 through a hopper 7. A fixed bottom platen 8 at the other end of the frame 2 supports the mould 1 of the present invention.

A top mould generally indicated at 9 is slidably supported above the mould 1 by a fixed top platen 10, which is mounted on posts 11. A clamping cylinder 12 is mounted on the fixed top platen 10, the piston 13 of the cylinder 12 extending downwardly through the platen 10 to the top mould assembly 9 for moving the top mould assembly between the closed and open positions (Figures 2 and 3, respectively). The top mould assembly 9 includes a movable platen 14 connected to the bottom of the piston rod 13, a cooling plate 15 and a top mould 16. The mould assembly 1 of the present invention is fixedly mounted on a carriage 18, which is slidable on tracks 19 (one shown) between a moulding position (Figure 2) and an unloading position (Figure 3).

The tracks 19 are mounted on the fixed bottom template 8, and extend outwardly beyond the end of the frame 1 for carrying moulded soles 6 out of the frame. The outer end of the tracks 19 slope downwardly, and are provided with end stops 20 for the carriage 18. Grooves 21 in the sides of the carriage 18 guide the carriage on the outer ends of the tracks 19. The carriage 18 is reciprocated on the tracks 19 by a cylinder 22 at the inner end of the track 19. A piston rod 23 extends outwardly from the cylinder 22 and is pivotally connected to the carriage 18 by a clevis 24.

With particular reference to Figures 4 and 5, the mould of the present invention includes a bottom mould 25 mounted on a cooling plate 26, and an intermediate mould 27. The bottom mould 25 is provided with a pair of recesses 28, which are closed by the intermediate mould to define mould cavities 29 (Figure 5). The intermediate mould 27 is pivotally connected to the bottom mould 25 by a piano hinge 30. The top mould 16 also includes recesses 32 (Figure 3), which are closed by the intermediate mould 27 when the top mould 16 is moved downwardly against the intermediate mould 27 to define mould cavities 33 (Figure 5).

Thermoplastic material is injected into all of the mould cavities 29 and 33 simultaneously from the extruder 5 through a square nozzle 34. The nozzle 34 has the same cross-sectional configuration as an injection port 35 in the intermediate mould 27. The nozzle 34 contacts the end of the intermediate mould 27 so that virtually all of the plastic enters the mould.

The injection port 35 in the intermediate mould 27 is merely a rectangular slot extending through the mould, so that when the mould is closed the inner end of the slot is located between the ends of the recesses 28. A groove 36 extends between the recesses 28 in the bottom mould 25. A similar groove 37 extends between the recesses 32 in the top mould 16. The grooves 36 and 37 are positioned so that they intersect the inner end of the injection port 35. Thus, plastic material injected into the port 35 enters the grooves 36 and 37 to fill the mould cavities 29 and 33. The ends 39 of each groove 36 and 37 are restricted to define small injection openings into the mould cavities 29 and 33.

In operation, the mould 1 is closed (Figure 2) by moving the top mould 16 downwardly into contact with the intermediate mould 27. Thermoplastic material is injected into the injection port 35. The outer layer of the plastic material in the port 35 hardens to form a skin. Throughout the remainder of the injection, the plastic material flows through the interior of the rectangular sprue 40. Thus, there is virtually no leakage of plastic around the inlet to the injection port 35. The mould 1 is opened, i.e. the top mould assembly 9 is moved upwardly (Figure 3). The piston rod 23 is extended to move the bottom mould 25 and intermediate mould 27 out of the frame 2 on the carriage 18. The intermediate mould 27 is opened (Figure 4) and all of the soles 6 are removed therefrom. Because of the large sprue 40, the soles remain on the intermediate mould 27 during opening of the mould. The sprue 40 is connected to the soles 6 by small, transversely extending sprues 41.

The mould of the present invention is best suited to the mass production of thin soles, which harden rapidly in the mould cavities, and which can readily be removed from the mould cavities.

Of course, a single mould cavity could be provided between each of the top and bottom moulds, and the intermediate mould, or alternatively more mould cavities could be provided between the top, intermediate and bottom moulds. It is readily apparent that the intermediate mould could be connected to the top mould rather than the bottom mould. However, it would then be necessary to provide means for holding the intermediate mould against the top mould in the closed position before lowering such moulds onto the bottom mould.

Claims (8)

1. A mould for moulding a plurality of footwear soles, comprising a bottom mould; an intermediate mould for closing on said bottom mould to define at least one first mould cavity with said bottom mould; a top mould for closing on said intermediate mould to define at least one second mould cavity with said intermediate mould; and an injection port in said intermediate mould for introducing mouldable plastics material into said first and second cavities for forming said soles.

2. A mould according to claim 1, including hinge means pivotally connecting said intermediate mould to one of said bottom mould and said top mould.

3. A mould according to claim 2, wherein said hinge means connects said intermediate mould to said bottom mould.

4. A mould according to claim 3, wherein said intermediate mould includes a plate, said hinge means connecting one end of said plate to said bottom mould; each of said bottom mould and top mould including a recess for defining a said mould cavity with said plate.

5. A mould according to claim 4, including a slot extending longitudinally in said other end of said plate defining said injection port; and grooves in each said bottom mould and said top mould for carrying plastics material from said injection port to said mould cavities.

6. A mould for moulding simultaneously a plu rality of footwear soles, substantially as herein be fore described with reference to the accompanying drawings.

7. A footwear sole moulded in a mould as claimed in any one of claims 1 to 6.

8. An article of footwear including a sole as claimed in claim 7.