METHOD FOR INJECTION MOULDING SAFETY FOOTWEAR
A method is provided for injection moulding a footwear product having a non-metallic insole integrally formed between a sole and upper of the product. A sole cavity formed between a sole plate and cover plate tightly closed together is injected to form a sole, wherein the cover plate is configured to establish an insole sole cavity directly above and adjacent to the sole cavity, the insole cavity configured to receive and hold a non-metallic insole over the sole. The cover plate is removed to expose the sole and the insole cavity there over. A non-metallic insole is inserted in the insole cavity whereby the non-metallic insole is held over the sole by the insole cavity. An upper cavity of an upper mould is injected to fill the upper cavity and form an upper attached to the sole, the upper mould comprising shells tightly closed together around a last over the sole plate when comprising the hardened injected sole therein and the non-metallic insole held in the insole cavity to prevent movement of the non-metallic insole during the injecting of the injection material into the upper cavity, the last having an exterior surface configured to correspond to the shape of an interior surface of the footwear product, and the upper cavity formed between the shells and the last.
1 . A method for injection moulding a footwear product having a non-metallic insole comprising:
(a) injecting under pressure flowable sole injection material into a sole cavity of a sole mould to fill the sole cavity and form a sole upon hardening of the sole injection material, the sole mould comprising a sole plate and cover plate tightly closed together wherein the cover plate is configured to establish between the tightly closed sole plate and cover plate an insole sole cavity directly above and adjacent to the sole cavity, the insole cavity configured to receive and hold a non-metallic insole over the sole;
(b) removing the cover plate and exposing the sole and the insole cavity there over;
(c) inserting a non-metallic insole in the insole cavity whereby the non-metallic insole is held over the sole by the insole cavity; and, (d) injecting under pressure flowable upper injection material into an upper cavity of an upper mould to fill the upper cavity and form an upper attached to the sole upon hardening of the upper injection material, the upper mould comprising shells tightly closed together around a last over the sole plate when comprising the hardened injected sole therein and the non-metallic insole held in the insole cavity to prevent movement of the non-metallic insole during the injecting of the injection material into the upper cavity, the last having an exterior surface configured to correspond to the shape of an interior surface of the footwear product, and the upper cavity formed between the shells and the last.
2 . A method according to claim 1 wherein the sole and upper injection materials are comprised of molten thermoplastic and the hardening of the sole and upper injection materials is by cooling the molten thermoplastic.
3 . A method according to claim 1 wherein the sole and upper injection materials are curable and the hardening of the sole and upper injection materials is by curing.
4 . A method according to claim 1 wherein the non-metallic insole is a safety insole.
5 . A method according to claim 4 wherein the footwear product is a safety boot.
6 . A method according to claim 1 wherein the cover plate comprises an undercut section angled inwardly of the vertical direction at an angle (e) from each of a front edge and a back edge the cover plate, wherein the size and shape of each undercut section and the angle (⊖) are chosen to optimize the fit of the non-metallic insole in the insole cavity.
7 . A method according to claim 6 wherein the size and shape of each undercut section and the angle (⊖) are chosen so the non-metallic insole snap-fits into the insole cavity.
8 . A method according to claim 1 wherein the sole injection material is a polymer material.
9 . A method according to claim 1 wherein the upper injection material is a polymer material.
10 . A footwear product made by the method of claim 1 .
11 . A footwear product according to claim 10 which is a boot or a shoe.