GB1570023A - Shoe sole and heel unit - Google Patents

Description

(54) SHOE SOLE AND HEEL UNITS (71) We, LUIGI VALENTINI and ANGELA VALENTINI trading as TAC CHIFICIO "VALE" di VALENTINI LUIGI e ANGELA both of Italian nationality and both of 63019 Sant'Elpidio a Mare (Ascoli Piceno) Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to the manufacture of shoes.

There are many processes for the manufacture of the moulded base, or lower portion, of a shoe of plastics material, in which the plastics material is substantially the same for the heel and also for the sole; there are likewise many processes for the manufacture of such a shoe base, with the heel attached to the sole in a step subsequent to the separate production of each of these two parts.

The steady increase in the use of such a lower part of a shoe and the correspondingly greater exploitation of plastics material, such as synthetic rubber or resin of an appropriate hardness, followed by the attachment of the heel and sole, not only to one another but also, necessarily to the upper, or remaining part of the shoe, has stimulated research intended to render easier and more economic the method of production, as well as giving the finished shoe an appearance and strength in accordance with the producer's aims and satisfactory to the wearer.

On aspect which has been the object of continuous attention in the manufacture of shoes with the sole and heel moulded in plastics material is, in particular, that of the method of joining the heel and the upper, in the remaining and corresponding upper part of the shoe, when the operation following the moulding is carried out. As is well known to technicians in this field it is generally regarded as essential that the heel, at least over a good depth of its upper portion, shall permit the secure insertion of the nails which join, in a reliable manner, the upper portion of the shoe to the lower portion produced by moulding.

According to this invention there is provided a process for producing a shoe heel and sole unit comprising applying adhesive to the upper surface, the front surface (which is to face forwardly in the finished heel and sole unit) and optionally the lower surface of a generally heel-shaped block at least the upper part of which is of material into which nails may be driven, positioning the block in a mould and injecting plastics material into the mould to form therein the sole and its joint to the heel and thereby form the sole and heel joined together as a single unit, the block forming a major part of the volume of the heel, the mould being of such a shape and the block being so positioned therein as to cause the formation of portions of the injected plastics material extending over and adhering to the said surfaces of the heel to which adhesive was appled with the side surfaces of the heel remaining exposed.

The block, previously made as an independent part having the required shape and hardness, and possibly also having been given a desired finish on the surfaces which will remain exposed, is inserted in the mould and becomes suitably joined to the sole part at the same time as the latter is shaped by injection moulding, forming a single sole and heel unit. The upper part of the shoe can then be joined to this sole and heel unit, made in moulded plastics material, with the normal assistance of nails. The block can be of differing hardness to the sole and its joint to the heel and substantially rigid so as to give the desired finished effect.

Examples of suitable materials for the block are hard synthetic rubber, a hard plastics material (suitably one harder than that which is injected into the mould to form the sole and heel unit) wood, or leather, always bearing in mind that at least the upper part of the heel should be suitable for the secure fixing of nails in the subsequent phase of manufacture of the shoe.

The lower surface of the block may constitutc the surface of the heel to bear on the ground when the shoe is worn. Alternatively the injected plastics material may cover this surface also, and provide the surface to bear on the ground.

The upper surface of the block, and optionally also its lower surface if this is to have plastics material adhering to it, may each be provided with at least one recess to act as a key for the plastics material, i.e. to give the plastics material a further opportunity of becoming joined by means of the adhesive.

The invention embraces sole and heel units made by the process of the invention, and shoes incorporating them.

Embodiments of sole and heel units prepared by the process of the invention will now be described by way of example, and with reference to the accompanying drawing in which: Figure 1 is a schematic representation mostly in longitudinal section, of a sole and heel unit; Fig. 2 is a schematic representation in exploded view and mostly in longitudinal section, of the two components, heel and sole, similar to those shown as a single unit in Fig. 1; and, Fig. 3 is a schematic representation, similar to that in Fig. 1. but where the heel is of a different material.

Referring to the drawing, and in particular to Fig. 2, substantially two main component parts form as a single unit each of the sole and heel units 10 shown in Figs. 1 and 3.

As shown in Fig. 2 a hard, rigid heelshaped block 11' has been previously prepared and also pre-finished with a covering of leather 20 stuck on the side surface of the heel. In these various forms shown in the drawing, the front surface 18 of the block (i.e. the surface which is to face forwardly in the finished unit) is concave and substantially vertical, while the upper surface 16 has a shape better adapted to support the wearer's heel when the shoe is given its final form. and also has a recess 17. In Figure 2 it is the lower surface 15' of the block 11' which bears directly on the ground as the wearer is walking. The heel, covered as described, is formed for example from rubber or hard synthetic resin (into which materials nails can be driven).The surfaces of the block which are to be joined to the plastics material during the injection moulding stage are coated with adhesive suitable for this purpose. Such adhesives are known per se, and are readily available commercially.

The block is placed in the appropriate position in a mould for the execution of a conventional injection moulding step to form the sole 12 with the plastics material selected for this. This step is akin to a conventional injection moulding process used to form a shoe sole, and uses plastics material conventionally used for the injection moulding of shoe soles. The plastics material flows to take up the shape predetermined by the mould, with a secure join between the surfaces 16', 17', 18' produced by the moulding and the corresponding ones 16, 17, 18 already provided on the block 11'.

The block 11' forms a major part of the volume of the heel in the finished sole and heel unit. The side surfaces 20, covered with leather, remains exposed.

The choice of material for the block 11', in particular its hardness and rigidity will be determined so as to achieve the desired characteristics for the shoe. Obtention of the desired characteristics is facilitated because these two main parts which make up the sole and heel unit can have different properties.

On the other hand, the possibility of varying the material forming the major part of the heel also enables the producer to make useful modifications, adapted to the various articles to be produced. So, for example, in Fig. 1 it was again desired to use prefinished heel-shaped block 11 of hard resin with a leather covering 20 but its lower surface is provided with a recess 19 and this again is coated with adhesive, because in the injection moulding phase this lower surface is also covered solidly with the plastics material used for the sole, this material forming a lower layer 15 which provides the surface of the heel which bears on the ground.

Fig. 3 has its heel-shaped block 11" prepared and pre-finished as in Fig. 1, but consisting of a different material, which may be chosen from those usually regarded as most suitable for shoe heels.

After the production of any these sole and heel units, the upper part of the shoe can then be joined to the sole and heel unit with the normal assistance of nails without the need for any preparatory operation on the sole and heel unit after moulding, and in particular on the upper part of the heel, because the necessary nailing fulfils the required demands as to the strength of the finished shoe.

The above description and the relative illustrations are not intended to be of a limiting nature regarding the execution of the present invention. It is not essential to util ise a block whis is fully pre-finished on its exposed surfaces before injection moulding heel, as described and illustrated above, although this may be preferred. It is possible under normal conditions to use a semifinished block which requires further processing and finishing on its exposed surfaces after formation of the sole and heel unit is described above, such as at the time of joining on the upper part oí the SI11)C SO as t() obtain the final article rcatly lor sale and use.

It is also conccivahle that, following the same manul'ncturing procedure and using the sime mould, it would be possible to place in suitable positions in the mould not only the prc-finished rigid heel but also a piece of leather or other material shaped as a sole and also having its tipper surface coated with adhesive as already mentioned for the hccl-forming block, so that the injection moulding operation again produces a sole and heel unit in resin, but in which the final walking surface of the sole is formed by the said shaped piece of leather or other material.

WHAT WE CLAIM IS: 1. A process for producing a shoe heel and sole unit comprising applying adhesive to the upper surface, the front surface (which is to face forwardly in the finished heel and sole unit) and optionally the lower surface of a generally heel-shaped block at least the upper part of which is of material into which nails may be driven, positioning the block in a mould and injecting plastics material into the mould to form therein the sole and its joint to the heel and thereby form the sole and heel joined together as a single unit, the block forming a major part of the volume of the heel, the mould being of such a shape and the block being so positioned therein as to cause the formation of portions of the injected plastics material extending over and adhering to the said surfaces of the heel to which adhesive was applied with the side surfaces of the heel remaining exposed.

2. A process according to Claim 1 wherein the upper surface of the block, and optionally also its lower surface if this is to have plastics material adhering to it, are each provided with at least one depression or recess to act as a key for the plastics material.

3. A process according to Claim 1 or Claim 2 wherein the block is of hard synthetic rubber, wood, leather or of plastics material harder and more rigid than the said plastics material.

4. A process according to Claim 1, Claim 2, or Claim 3 wherein a desired finish is applied to side surfaces of the block which remain exposed in the sole and heel unit, prior to positioning the block in the mould.

5. A process according to any one of the preceding claims wherein a piece of material to form the walking surface of the sole, and having adhesive applied to an upper surface thereof, is also positioned in the mould before the injection of the plastics material.

6. A process for producing a shoe sole and heel unit substantially as herein described with reference to any of the accompanying drawings.

7. A shoe sole and heel unit produced hy the process ol any one of the preceding

Claims (1)

1. claims.

   X. A shoe sole and heel unit substantially as herein described with reference to any of the accompanying drawings.

   9. A shoe incorporating a sole and heel unit according to claim 7 or claim 8.