GB2025201A - Improvements in or relating to flexible moulded sole units for footwear - Google Patents

Abstract

The invention relates to footwear including inserts embedded in flexible sole units and a method of making said footwear comprising the steps of providing an insert (1) of rigid plastics material having a fastener-securing portion (2) and a retaining portion (6), mounting said insert in a desired portion adjacent a side wall of a mould cavity of a mould for a sole unit, moulding a sole unit from flexible plastics material so that said material flows around the insert at least substantially to embed it, and fastening marginal portions of the upper (10) to side surfaces of the sole unit (12) by inserting fasteners (8) into the fastener-receiving portion (2) of the insert (1). The fastener-securing portions of the or each insert may comprise a bore for receiving a nail or a screw in a force fit. <IMAGE>

Description

SPECIFICATION Improvements in or relating to flexible moulded sole units for footwear The invention is concerned with improvements in or relating to flexible, moulded sole units for footwear and a method of making footwear incorporat ing such sole units.

It is known to provide sole units for footwear which are made from wood and other rigid materials, such as plastics materials, the sole unit having an upper affixed thereto by means of adhesive or alternatively the upper overlapping side surfaces of the sole unit and being secured thereto by means of nails, screws or the like, the latter construction is used particularly in clogs. It is also known to provide flexible sole units an upper being attached thereto by means of adhesive. Hitherto it has not been possible to provide a flexible sole unit having an overlapping upper which is fixed thereto by means of nails, screws and the like. This is because the flexibility of the material renders it incapable of receiving screws, pins or the like in a secure manner.

The invention provides a flexible sole unit for footwear comprising a sole body portion of moulded flexible plastics material having embedded therein at least two inserts of rigid material having a fastener-receiving portion arranged adjacent to a side surface of the sole body and a retaining portion inwardly spaced from said side surface.

The invention further provides an insert for use in the sole unit above described, moulded from rigid plastics material and comprising a fastenerreceiving portion adapted to receive screws, nails, tacks or the like in a secure manner and a retaining portion adapted to be keyed into the flexibile plastics material of the sole body to prevent accidental displacement of the insert in use.

Conveniently, the retaining portion is of larger dimensions than the fastener-receiving portion and thus provides shoulders or the like around which the flexible plastics material will flow in a moulding operation. Alternatively or additionally, the retaining portion may be provided with apertures, grooves or the like in order to provide keying surfaces. Advantageously, the insert may be provided with a bore passing at least through the fastener-receiving portion of the insert in order to facilitate entry of the fastener into the insert.

The invention still further provides a method of making footwear comprising a flexible sole unit and an upper comprising the steps of providing an insert of rigid plastics material having a fastener-securing portion and a retaining portion, mounting said insert in a desired portion adjacent a side wall of a mould cavity of a mould for a sole unit, moulding a sole unit from flexible plastics material so that said material flows around the insert at least substantially to embed it, and fastening marginal portions of the upper to side surfaces of the sole unit by inserting fasteners into the fastener-receiving portion of the insert. The fastener-securing portion of the or each insert may comprise a bore for receiving a nail or a screw in a force fit.

The inserts are mounted in the mould by suitable mounting means, which may comprise for example a retractable pin which, during moulding, extends into the mould cavity and upon which the or each insert is mounted, the pin being located in the fastener-securing bore. Preferably, means are provided for retracting the pin from the mould cavity after moulding to allow the sole unit together with the or each insert, to be removed. Desirably a number of inserts are provided there being mount ing means for each of the inserts, which may be provided by a number of retractable pins, at least one for each insert.

An example of the invention will now be described, with reference to the accompanying drawings. It will be understood thatthe description is given by way of example only and not by way of limitation.

In the drawings: Figure 1 is a perspective view of an insert for use according to the invention; Figure 2 is perspective view of a shoe according to the invention shown partly cut-away to reveal an insert as shown in Figure 1.

Figure 3 is a cross-sectional view through the insert of Figure 1 on line Ill-Ill; Figures 4,5 and 6 are perspective views of a Iternative forms of inserts according to the invention; and Figure 7 is a schematic plan view of a moulding device prior to moulding of a sole unit according to the invention.

Figure 1 shows an insert 1 comprising a fastenersecuring portion 2 which is provided with a bore4 into which is to be received a fixing pin of slightly larger diameter than the bore, in a force fit. The insert also comprises a retaining portion 6 which is of larger dimensions relative to the fastenersecuring portion 2, so that when the insert is surrounded by the flexible plastics material from which a sole unit is to be moulded, the insert is anchored firmly therein.

Figure 2 shows an insert of the type shown in Figure 1 positioned inside a moulded sole unit 12, a plurality of these inserts being provided to receive the shanks of pins 8 which secure marginal portions of an upper 10 to the sole unit 12. The pins 8 are received as a force fit in bores 4, shown in Figure 3, extending through the insert 1.

Figure 4 shows a multiple insert which comprises a number of inserts similar to that shown in Figure 1 linked by webs 14. By reason of their narrow crosssection, these webs 14 lack the rigidity of the inserts themselves. This type of multiple insert may be useful where fasteners are required to be embedded into the sole unit at closely spaced intervals.

Figure 5 shows a further insert similar to that shown in Figure 1 but having two bores 4 instead of one bore. This would be suitable for applications where the shanks of nails or the like are to be received in pairs or alternatively where the fastener has, for instance, two shanks; a typical example being a staple.

Figure 6 shows an alternative insert, having a retaining portion 6 with a curved contour.

Figure 7 shows a schematic plan view of a mould ing device 20, having a mould cavity 22. A number of retractable pins 24 extend through walls of the mould into the mould cavity 22, each pin being operable by a mounting/retracting mechanism 26 (only one of which is shown) which retract the pins into the walls of the mould to enable a moulded sole unit to be removed therefrom.

The mechanism 26 may be provided by a known lever system or any suitable known mechanical, electromechanical or pneumatic piston assembly.

In use, the mould device 20 is prepared for moulding by extending the pins 24 so that they project into the cavity 22 and an insert 1 is positioned on each pin, the pin extending into a bore 4 of the insert. The inserts are preferably aligned such that they touch or are closely adjacent to the side walls of the mould cavity. The cavity is then closed and plastics material is then moulded around the inserts in known manner, the resulting sole unit having the inserts moulded integrally therein. The pins 24 are then retracted into the walls 20 of the mould whereupon the completed sole unit may then be removed from the opened mould device. It will be noted that the sole unit will have small holes from which the pins were retracted. After being finished or decorated as required the sole is then transferred to receive an upper.Typically, a nailing machine will be used for attaching the upper and desirably this will be arranged such that the nails are driven in with the same, or nearly the same geometry, alignment and orientation of the pins 24 so that the nails are received in the bores 4 of the inserts.

Any convenient number of inserts may be provided in the sole unit and these may be multiple formation as desired. Obviously, the number of fastener-securing portions per sole unit will depend on the number of fasteners to be used to secure the upper.

If preferred, the or each bore 4 may extend only part of the way into the insert. Alternatively, where no bores are present, the or each insert may be held in the mould cavity by, for example, a jaw arrangement.

The retaining portion may be of any convenient shape which will prevent the insert being removed from the moulded sole unit and, for example, may include apertures shoulders, grooves or any other configuration which provides a keying surface.

The sole unit is preferably foamed polyurethane but may be made from any suitable flexible material, such as thermoplastics rubber or PVC, and may be moulded by injection or pouring as appropriate.

The insert may be made of any suitable material such as polypropylene, nylon, thermoplastics materials, thermosetting material, wood or even metal.

Claims (12)

1. Flexible sole unit for footwear comprising a sole body portion of moulded flexible plastics material having embedded therein at least two inserts of rigid material having a fastener-receiving portion arranged adjacent to a side surface of the sole body and a retaining portion inwardly spaced from said side surface.

2. A sole unit as claimed in claim 1 wherein there are a plurality of inserts arranged in a row at opposite side surfaces of the sole unit.

3. A sole unit as claimed in either one of claims 1 and 2, wherein each insert is provided with a bore passing through the fastener receiving portion thereof to facilitate entry of a fastener.

4. A sole unit as claimed in any one of the preceding claims wherein the retainer portions of the inserts are provided with grooves apertures or the like to act as keying surfaces for the flexible plastics material.

5. A sole unit as claimed in any one of claims 1 to 4, wherein the retainer portions of the inserts are of larger dimensions than the fastener-receiving portions and are provided with keying shoulders embedded in the flexible plastics material.

6. An insert for use in the sole unit of claim 1, comprising a fastener receiving portion having at least one bore passing therethrough and a retaining portion having keying portions or surfaces.

7. A plurality of inserts as claimed in claim 6 linked together in a side-by-side formation by means of integrally moulded web portions.

8. A method of making footwear comprising a flexible sole unit as claimed in claim 1 together with an upper, comprising the steps of providing an insert of rigid plastics material having a fastener-securing portion and a retaining portion, mounting said insert in a desired position adjacent a side wall of a mould cavity of a mould for a sole unit, moulding a sole unit from flexible plastics material so that said material flows around the insert at least substantially to embed it, and fastening marginal portions of the upper to side surfaces of the sole unit by inserting fasteners into the fastener-receiving portion of the insert.

9. A method as claimed in claim 8, wherein said inserts are mounted in the mould cavity by means of retractable pins which in use extend into the cavity and are retracted to allow the sole unit to be released when moulded.

10. A flexible sole unit for footwear constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

11. An insert for use in a flexible sole unit for footwear constructed and arranged substantially as hereinbefore described with reference to and as shown in (a) Figures 1,2and3, (b) Figure 4, (c) Figure 5, or (d) Figure6 of the accompanying drawings.

12. A method of making footwear comprising a flexible sole unit as claimed in claim 10, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.