Overmolding a Hard Heel Into a Soft Shoe The Factory Method Behind a Hands-Free Moulded Shoe

This application covers three ways of manufacturing a moulded shoe in which a hard heel piece is moulded into a softer shoe body. It was filed by Skechers U.S.A., Inc. II, names Chase Greenberg and Abel Casas as inventors, and is a divisional of Australian application 2024441060. It was filed on the same day as AU 2026202270, which shares the same title and description but claims the finished shoe. This one claims only methods of making it.

The Problem

The specification sets out no background problem. Its field statement says only that the innovations address footwear, and the object stated in the summary is the generic one of overcoming or ameliorating a disadvantage of existing arrangements. What the description does show is the manufacturing difficulty that this set of claims addresses.

A shoe that can be put on without hands needs a heel that is firmer than the rest of the shoe. In a moulded shoe, that means two or more plastics of different hardness have to end up fused together in one finished piece, and a loose heel piece has to be held in the right place inside a mould while the soft plastic flows around it. The description spends its manufacturing passages on exactly this: how to place the heel piece, how to hold it, and how many moulds to use.

What This Invention Does

This application has three independent claims, and all are methods. None claims a shoe.

Claim 1 is a method of making footwear in which a first plastic is supplied to a first shoe mold to give a heel insert substrate. That substrate is placed into a second shoe mold, and a second plastic is supplied to the second mold to overmould the heel insert substrate and give a shoe. The first plastic is harder than the second, and a portion of at least one of the plastics extends from the sole structure up to at least part of the rear heel collar. In plain terms, the hard heel is moulded first, dropped into a second mould, and covered by the softer plastic.

Claim 6 is a three part method. A first plastic of a first hardness is injected into a first mold to form a heel insert. A second plastic of a second hardness is injected into a second mold to form an upper heel substrate, and a third plastic of a third hardness is injected into a third mold to form a sole substrate. The three pieces are then positioned and uniformly moulded in a fourth mold. Dependent claim 8 says the first and second hardness may be the same, so the claim does not require the heel to be harder. Dependent claims 10 and 11 name materials: ethylene vinyl acetate (EVA), compression moulded EVA, thermoplastic polyester elastomer (TPEE) and thermoplastic polyurethane (TPU) for the first, and TPEE for the second.

Claim 16 places a heel cup of a first hardness into a mold, positions a heel cup overmould of a second hardness next to it, injects a plastic of a different hardness, and moulds that plastic onto both to form the shoe structure. Again a portion of the heel cup or overmould must run from the sole structure to the rear heel collar. Claim 20 gives the heel cup an S wave profile with an upper arc and a lower arc, and claim 21 forms the heel cup and overmould by injection co-moulding.

The description supports the claims with process detail. Plastics can be injected, or in an alternative the mould is cleaned and plastic pellets are poured into the midplate and bottom plate, followed by a first hot press of 30 seconds or less and a second of about 20 minutes. The heel insert carries a securing feature, such as an instep strap or clip, that holds it on the core or last of the mould, which claims 4 and 15 pick up. Hardness examples are given on the Shore C scale: heel at or near 60 with the upper and sole at or near 40, or heel near 52 with the rest near 45. The description reports no production yield, cycle time or scrap figures for these methods.

Key Features

• Overmoulding the heel. In claim 1 the hard heel insert is moulded first, placed in a second mould, and covered by the softer plastic so that the two fuse. The specification says the same mould may be used twice (claim 5).
• Separate moulds for each part. Claim 6 forms the heel, upper heel and sole in three moulds and then joins them in a fourth, which allows each part its own hardness and, as the description notes, its own colour.
• A securing feature on the heel insert. The description has the heel insert held on the mould core by an instep strap or clip, so that it does not shift when the second plastic is injected. Claims 4 and 15 cover this.
• Heel to collar continuity. Claims 1, 16 and 22 require plastic to run from the sole structure up to at least part of the rear heel collar, so the heel piece reaches the top of the shoe rather than sitting only at the bottom.
• Injection or pellet pouring. Claims 2, 3, 13 and 14 allow either injection moulding or pouring plastic pellets into the mould.
• Named materials and an S wave heel. Claims 10 and 11 list EVA, TPEE and TPU, and claim 20 gives the heel cup an S shaped section, matching the heel geometry in the sister application.

Who Is Behind It

The applicant is Skechers U.S.A., Inc. II, the operating entity of the footwear company Skechers, founded in 1992 by Robert Greenberg and headquartered in Manhattan Beach, California. FashionUnited reported in September 2025 that 3G Capital had completed its takeover of the company, taking it private at about 9 billion dollars, with Robert Greenberg remaining chief executive.

The two named inventors are Abel Casas and Chase Greenberg. The specification gives no biography for either,, so no more is said here. The same two inventors and the same description appear on AU 2026202270, the sister divisional claiming the shoe itself.

On priority, the description states that it claims priority under 35 U.S.C. 119 to US provisional application 63/636,403 filed 19 April 2024, and that it is a divisional of Australian application 2024441060, the national phase of PCT/US2024/052684 filed on 23 October 2024. The priority country is the United States.

Why It Matters

How two claim sets differ is the useful thing to know about this pair. AU 2026202270 claims the product: a moulded upper, sole and heel cup with a hardness difference, and a heel cup that deforms. AU 2026202271 claims no product at all and covers the process for building one. A competitor making a similar shoe by a different route would have to read the first, and a competitor using a two shot overmould process would have to read the second, even if the shoe it makes looks different.

For a manufacturer the interest is in the process. Injection moulding a single plastic is simple, but a shoe with stiff and soft zones means managing several shots, several moulds and an insert that has to be located exactly. The securing strap is a small mechanical answer to a real shop floor problem. Splitting the shoe and the method into separate divisional applications also lets each be pursued and, if needed, challenged on its own.

Related Concepts

• Injection moulding – the process family, including overmoulding, that the claimed methods use.
• Shore durometer – the hardness scale used for the heel and body plastics in the examples.
• Thermoplastic polyurethane – a material named in the dependent claims for the harder heel piece.
• Ethylene-vinyl acetate – the foam plastic named in claim 10 and common in shoe midsoles.
• Thermoplastic elastomer – the family that includes the polyester elastomer named in claims 10 and 11.

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AU 2026202271 was published in the Australian Official Journal of Patents on 9 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.