| 摘要 |
In the molding of boot and shoe heels a foamable plastics molding material is injected into a heel mold and a pressurized gaseous fluid is injected into the heel body after it has formed an outer skin against the mold inner surfaces but before it has fully set in order to displace and compress the foaming material and form within the heel at least one enclosed hollow chamber which provides a different degree of resilience to heel strike forces at the location of the chamber. A plurality of closely adjacent chambers may be provided to obtain the same effect, particularly when the heel is shallow. A preformed member may be placed in the mold to form the heel outer surface and ensure a minimum heel wall thickness at this location. The invention also includes apparatus for making such heels, and the heels when so made. The molded body may comprise a sole with an integral heel part. The enclosed chamber may be vented to the ambient atmosphere or it may be sealed. The chamber may be at least partly filled with a material of resilience different from that of the material from which the heel is molded. In another method a chamber is formed in the heel by a preformed hollow member attached to the underside of the boot or shoe upper, the member being incorporated into the shoe heel by the molding operation. An insole has a plug of lower resilience material that fits into the chamber formed by the hollow element to determine the resilience to heel strike.
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