GB2189678A - Footwear - Google Patents

Abstract

In a method of manufacturing an article of footwear, a sock (6) is secured into the lower end of an upper (5) to close that end, the upper having an external pile fabric surface. The upper is placed on a last so that the join line (7) between the upper and the sock closely follows the whole of the feather line (8) of the last. A sole-defining closed mould cavity (4) is formed below the lasted assembly and a liquid plastics material injected into the cavity and cured to form a sole on the sock. Sole material is thus not permitted to overlie the pile of the upper, so avoiding the problem of pile strike through. <IMAGE>

Description

SPECIFICATION Article of footwear This invention relates to an articleoffootwear, and to a method offorming such an article.

One commercially available style offootwear, used particularlyfor slippers, comprise an upper having an external pile fabric surface. A sock is secured to the upperto close the lower opening thereof, and a sole is applied to the sock and to an inwardlyturned lower edge of the upper. When the sole is formed from a rubber compound the act ofmoulding the compound onto the lasted upper and sock combination com pressesthe pileon the inturned edge ofthe upper, and the finished shoe exhibits a clean junction between the sole material and the pile fabric material ofthe upper.

An increasing volume offootwear now has soles formed by injection moulding techniques using a liquid plastics material such as polyvinyl chloride.

However, problems have been experienced in provid ing injection moulded soles onto pile fabric uppers, in thatthe plastics material does not compress the pile of the inturned edge ofthe upper, and accordingly the pile tends to strike through the plastics material around the outer edge of the sole. The degree of strike through can varyfrom an actual projection of pile fabric beyond the plastics material of the sole to a distinct discoloration of the sole edge due to part of the pile fabric being visible close to the surface of the plastics material.Attempts have been made tore- move the pile from the critical area,forexample by shaving or burning techniques, and also to match the colour of the sole compound to the colour of the pile.

However, none of these methods have given a commercially attractive product, and the industry has generally accepted that footwear of this type cannot be made.

The present invention seeks to overcome the problem and to provide an attractive and commercially acceptable article of footwear.

According to afirstaspectofthe invention a method offorming an article offootwear comprises providing an upper having an external pile fabric surface and a sock secu red to the upperto close the lower opening thereof, fitting the combined upper and sock onto a last so thatthejunction of the sock and the upper closely follows the whole of the feather line of the last, forming a sole-defining closed mould cavity belowthe lasted construction with the upper boundaryofthe cavity defined bythefeatherlineofthe iast, injecting a liquid plastics material into the mould cavity, and curing the plastics material to form a sole bonded to the sock.

From another aspect of the invention we provide an article of footwear comprising an upper having an external pile fabric surface, a sock secured to the upperto close the lower opening thereof and a sole formed from a cured liquid plastics material bonded to the sock, in which the junction line between the upper and the sock is substantially coincident along the whole of its length with the junction line between the sock and the sole.

The invention is based onthe realisation thatthe problem with earlier techniques arose from a turned in edge of the pile fabric lying belowthe feather line of the last so that it was essential that it be covered with the sole material. In the technique of the invention the junction between the pile fabric surface and the sock fabric is designed to follow as closely as possiblethe feather line ofthe mould, with the resultthatthe boundary orjunction line between the upper and the sock will be substantially coincident along the whole of its length with the boundary or junction line between the upper and the sole of the finished article.

Thus, the injected sole material covers only the sock fabric and notthe pile fabric ofthe upper, and the problem of pile strike through is avoided.

It is recognised that it is difficultto obtain exact coincidence between the boundaries referred to, and it is therefore preferred thatthe sock be of a fabric that substantially matches the pile ofthe pile fabric in both colour and surface finish. Thus, if there is a small strip of sock fabric remaining exposed after moulding of the sole this is almost unnoticeable as it blends with the pile fabric. The sockfabric is desirably a flat surfaced fabric of any suitable weave pattern, although otherfabrics are possible, for example very short pilefabrics, as long as no part of the fabric will strike th rough the liquid plastics material.

The plastics material used for the sole is preferably polyvinyl chloride, although other liquid plastics materials that can be used will be apparentto those skilled in this field.

In orderthatthe invention may be better understood a specific embodimentthereofwill now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure lisa plan view of the base of a last, part being shown with an upper construction lasted thereon; Figure 2 is a schematic cross-section through a last and mould during manufacture of an article of footwear; and Figure 3 is a partial section through a finished article of footwear.

Referring to the drawings, Figures 1 and 2 show schematically a last 1 and mould parts 2 and 3, which may be relatively moved into the position shown in Figure 2 to define a mould cavity 4shaped to define a required sole construction. The sole is formed by injecting a liquid plastics material into the mould cavity, and curing the material, using any of the techniques known in the art, and detailed description ofthis step is unnecessary.

Prior to the step of moulding the sole, a combined upper and sock structure has been lasted onto the last 1. The upper5 is formed to have an external pile fabric surface, and the sock is formed from a suitable fabric 6, stitched to the lower edge of the upper around a stitch line7 in ordertoclosethe lower opening of the upper. The sockfabric6 is of a colour and surface finish that is a reasonable match to the pile of the pile fabric.

The upperandthesockare cutand are stitched togeth er so thatthejunction ofthe sock and the upper closely follows the whole of the feather line 8 of the lastwhen the upper has been properlypositioned on the last. Thus, substantially the whole of the last surface below the feather line is covered by sock material 6,while the relevant last region above the feather line is covered bythefabric of the upper.

Itwill thus be apparent from Figure 2 that when liquid plastics material is injected into the mould cavitythe plastics material will contact and bond only to the sock fabric, and there will be little, or preferably, no contact between the sole material and the pile fabric. Thus, in the finished article offootwearthe junction line between the upper and the sockwill be substantially coincident along the whole of its length with the junction line between the sock and the sole.

Exact coincidence is difficult to achieve, and in practice there will probably be a very narrow stripS of sockfabricvisible between the sole and the pile fabric.

However, using a sockfabricthatsubstantially matches the pile of the pilefabricthis strip can be made virtually indistinguishable.

It is, of course, preferable to err on the side ofthe strip 9 being too wide ratherthan too narrow, as in the lattercasethere can be a dangerof part ofthe pile fabric being displaced to belowthefeather line.

It should be noted that the method ofthe invention provides a further advantage, in that during lasting the fitting of the stitch line 7 around the feather line automatically positions the upper properly on the last.

Claims (8)

1. A method of forming an article offootwear comprising providing an upper having an external pile fabricsurface and a sock secured to the uppertoclose the lower opening thereof, fitting the combined upper and sock onto a last so thatthejunction of the sock and the upper closely follows the whole of the feather line ofthe last, forming a sole-defining closed mould cavity below the lasted construction with the upper boundaryofthe cavity defined bythefeather line of the last, injecting a liquid plastics material into the mould cavity, and curing the plastics material to form a sole bonded to the sock.

2. A method according to claim 1 in which the sock is of a fabric that substantially matches the pile ofthe pilefabricin both colour and surface finish.

3. A method according to claim 1 or claim 2 in which the plastics material is polyvinylchloride.

4. A method of forming an article of footwear, substantially as herein described with reference to the accompanying drawings.

5. An article offootwearcomprising an upper having an external pile fabric surface, a sock secured totheuppertoclosetheloweropeningthereofand a sole formed from a cured liquid plastics material bonded to the sock, in which the junction line between the upper and the sock is substantially coincident along the whole of its length with the junction line between the sock and the sole.

6. An articleoffootwearaccording to claim 5 in which the sock is of a fabric that substantially matches the pile of the pile fabric in both colour andsu rface finish.

7. An article of footwer according to claim 5 or claim 6 in which the plastics material is polyviny Ichloride.

8. An article of footwear substantially as herein described with reference to the accompanying drawings.