GB2086301A - Improvements in injection moulding machines for footwear - Google Patents

Abstract

The application relates to injection moulding of footwear on a rotary table provided with a plurality of moulding stations in which at the penultimate station the footwear on a last is located in a heating box provided with a double counterweighted lid to automatically close over the footwear on the last and to automatically open when the shoe on the last is lifted therefrom, the moulding operation and the heating operation being carried out in the same cycle.

Description

SPECIFICATION Improvements in injection moulding machines for footwear This invention relates to improvements in injection moulding machines for footwear.

A machine has been proposed in which a rotary table is provided with a plurality of moulding stations each provided with a moulding head. A shoe upper on a last is placed on the table at a first station and then moves to a second station where a split mould is closed onto the last with a space around the base of the last into which a molten liquid compound is introduced to form a sole at the base of the upper. The machine is rotated to bring a second head to the mould filling position.

The machine is progressively rotated until the first head reaches the penultimate station where the last and the upper and the newly formed sole, which together form a shoe, are removed. The molten compound cools and sets during rotation of the table and the two halves of the mould open and the shoe on the last is removed and replaced by a further shoe upper on a last and the cycle is repeated. The last with the upper and moulded sole thereon is then transferred to a further machine for heat curing the upper in an oven to set the shoe to the size of the last.

The object of the invention is a machine which in the cycle for moulding the shoe sole will also cure and set the shoe to the shape of the last.

According to the invention a method for moulding footwear comprises applying a shoe upper on a last to a rotary table at a first station rotating the table to a second station closing a split mould around the base of the last and injecting a molten compound into the mould around the base of the last to form a sole attached to the upper, allowing the mould to cool at further stations and passing the upper and moulded sole on the last to a penultimate station to be raised into a heated curing and shoe setting box and finally removing the cured shoe from the last.

A machine for carrying out the method comprises a rotary table, a plurality of stations on the table each station having a split mould and heat setting box to receive a shoe upper on a last for lowering onto a mould cavity, means for supplying a molten material to the mould cavity, a lid on the heat setting box into which the last is lowered and heating elements in the heat setting box to cure the upper material.

The invention will be described with reference to the accompanying drawings in which; Fig. 1 is a diagrammatic view of stations on a rotary table of an injection moulding machine of the present invention; Fig. 2 is a perspective view of one embodiment of a mould and heat setting box in the open postion showing a shoe upper on a last at a moulding station; Fig. 3 is a transverse section along the X-X of Fig. 2, to a larger scale; Fig. 4 is a similar section to that in Fig. 3 showing the mould in the closed position; and Fig. 5 is a perspective view of a second embodiment of a mould and heat setting box in the open postion showing a shoe upper on a last at a moulding station.

A machine for carrying out the method comprises a rotary table 1 divided up into a plurality of stations and at each station 21-28 as shown in Fig. 1 a split heat setting box 4 is located above the split mould 5, as shown in Figs. 2 to 4.

A shoe upper A of a resilient material, for example suede, leather or plastics material such as P.V.C., is stretched over a last 3 and applied to a first station 21 on the table 1 moves to a second station 22 where the split heat setting box 4 and the split mould 5 are closed over the last 3. A molten compound is applied to the mould cavity 6 of the mould 5. The last 3 moves onto further stations to allow the molten compound in the mould cavity 6 to cool. At a penultimate station 27 the mould 5 is opened and the last 3 with the upper A and newly moulded sole thereon, passes onto the heated setting box 4 to set the shoe to the size of the last 3. At a final station 28, the last 3 and finished shoe are removed from the machine.

The heat setting box 4 as shown in Figs. 2 to 4 comprises a substantially rectangular chamber with electric heating elements 7 located adjacent the side walls. The top of the box is closed by two half-lids 9 and 10 each pivoted on one respective longitudinal side to close downwardly. Each halflid 9 and 10 is formed with a bar 11 extending substantially at right angles to the half-lid from the free edge of the half-lid. The half-lids are counterbalanced into the open position by weights 12 mounted on bars 13. As the upper A on the last 3 is lowered into the box 4 it moves the bars 11 downwards to close the top and rests on the mould cavity 6 as shown in Fig. 4. The inner edge of each half-lid 9, 10 is cut away to close round the uppermost portion or neck of the last 3.After curing, the last 3, the upper A and the newly formed sole are raised from the box 4 the half-lids 9, 10 being opened by the counter weights 12 as the weight of the last 3 on the bars 11 is removed.

Each half-lid 9, 10 of the split heat setting box 4 is provided with a restrictor bar 14 extending outwardly on its hinge side to engage the side of the box when the lid is open to prevent the two half-lids 9, 10 from opening beyond the vertical.

In another embodiment of the split heat setting box 4, as shown in Fig. 5, a one-part lid 1 5 is located around the neck of the last 3.

After removal of the last 3, the upper A and the newly formed sole from the box 4 the table 1 rotates to the final station 28 where the last 3 and cured and set shoe are removed from the machine.

Prior to moulding an insole may be applied to the upper A on the last 3 and attached thereto by heat setting adhesive.

The term shoe referred to herein is intended to cover any boot or shoe or other footwear and the molten compound may be P.V.C. or other mouldable material.

The method described simplifies the production of moulded footwear by the production of a moulded, cured and set shoe in a single cycle of operations thereby obviating the necessity for an independent oven and relasting for curing and setting the shoe.

Claims (8)

1. A method for moulding footwear comprising applying a shoe upper on a last to a rotary table at a first station, rotating the table to a second station closing a split mould around the base of the last and injecting a molten compound into the mould around the base of the last to form a sole attached to the upper, allowing the mould to cool at further stations passing the moulded sole on the last to a penultimate station to be raised into a heated curing and shoe setting box and finally removing the cured shoe from the last.

2. A machine for carrying out the method of claim 1, comprising a rotary table, a plurality of stations on the table, each station having a split mould and heat setting box to receive a shoe upper on a last for lowering onto a mould cavity, means for supplying a molten material to the mould cavity, a lid on the heat setting box into which the last is lowered and heating elements in the heat setting box to cure the upper material.

3. A machine as claimed in claim 2 having a lid comprising two half-lids and a counterweight attached to each half-lid to open said half-lids when the last is raised from the heat setting box.

4. A machine as in claim 2, in which the lid for the heat setting box is formed in one or two parts.

5. A machine as claimed in claim 2 or 3 having restrictor bars connected to the counterweights to engage the sides of the mould.

6. A method for moulding footwear substantially as hereinbefore described. -

7. A machine for moulding footwear substantially as described with reference to the accompanying drawings.

8. Footwear moulded on a machine as claimed in claim 2, substantially as described.

8. Footwear moulded on a machine as claimed in claim 2 substantially as described.

New claims or amendments to claims filed on 15/12/81.

Superseded claims, All.

New or amended claims:

1. A method for moulding footwear comprising applying a shoe upper on a last to a rotary indexing table at a first station of a multi-station table, indexing the table to a second station to lower the last into a split mould and closing the sides and the top of the mould indexing the table to a third position and injecting a molten compound into the mould around the base of the last to form a sole attached to the upper, allowing the mould to cool at further stations and indexing the upper and moulded sole on the last to a penultimate station any applying heat to pipes in the sides of the mould to cure the shoe on the last and finally removing the cured shoe from the last.

2. A machine for carrying out the method of claim 1, comprising a horizontal multi-station indexing table, a plurality of stations on the table, each station having a combined split mould and heat setting box to receive a shoe upper on a last for lowering into the mould cavity, counter weighted half lids to open, and close the top of the mould and heating pipes behind the sides of the mould to cure the moulded upper on the last.

3. A machine as claimed in claim 2, having a cover comprising two half-lids and a counterweight attached to each half-lid to open said half-lids when the last is raised from the mould.

4. A machine as in claim 2, in which the lid for the heat setting box is formed in one or two parts.

5. A machine as claimed in claim 2 or 3 having restrictor bars connected to the counterweights to engage the sides of the mould.

6. A method for moulding footwear substantially as hereinbefore described.

7. A machine for moulding footwear substantially as described with reference to the accompanying drawings.