WO1992001398A1

WO1992001398A1 - Soles

Info

Publication number: WO1992001398A1
Application number: PCT/GB1991/001132
Authority: WO
Inventors: Paul Anthony Stephen Cockburn
Original assignee: Uk Safety Group Limited
Priority date: 1990-07-25
Filing date: 1991-07-10
Publication date: 1992-02-06
Also published as: AU8203191A; GB9016281D0

Abstract

This invention relates to soles and footwear incorporating such soles. A sole portion (11) defines a number of air voids (16), each of which has an upper opening (17), formed by the necks of the heads of the moulding tool used to define the voids. In the preferred embodiment a cone (20) surrounds the opening (17). Each cone (20) can be compressed by the application of an upper, when a piece of footwear is being formed so that the cone pinches the opening (17) preventing filler from entering the void (16).

Description

SOLES

This invention relates to soles and to footwear incorporating such soles.

In order to improve the feel of articles of footwear many designs have been created which incorporate voids in moulded soles. These generally either take the form of integrated systems whereby air can be pumped from one group of voids to another with resilient energy absorption, or the voids are filled with a material of different density. From one aspect the invention consists in a sole having a plurality of sealed air voids.

Because the air voids are sealed one from the other they will each act as energy storage devices, in contrast to the above mentioned arrangements which are energy absorbing, and thus give a "springier" feel to the sole.

From a further aspect the invention consists in a moulded sole having an array of air filled voids each with an opening extending to the upper face of the sole and means for preventing penetration of filler, adhesive or the like into the sole during attachment of the sole to an upper.

The penetration preventing means could comprise a plug of material for each opening, for example an injection of adhesive from a gun. This is however difficult to automate because a range of sole sizes is always required and if not automated, it is labour intensive. A second possibility is to cover the sole with a scrim or other coating to prevent penetration during the injection of filler or adhesive, but this will reduce the adhesion between the sole and the upper. The scrim could either be broken up into sections to cover individual openings or groups of openings or it could be perforate. In the first case the more individual elements of scrim that are used the greater the labour and in the second case alignment becomes a problem. The scrim or covering could be replaced by small inserts which could be interlocked in groups. In a particularly preferred arrangement the penetration preventing means includes a formation moulded on the sole adjacent or circumjacent each opening and formed such that either they are deformed or deflected by application of a lasted upper on the sole and/or the pressure of the filler, adhesive or the like causes the formation to close or restrict the respective opening.

For example, the formation could be generally conical and surrounds and defines the opening, in which case the pressure acting on the sloping faces of the cone will tend to block the opening. Even if the opening is not fully closed, a narrow opening will prevent air passing out of the void and hence the resultant compressed air within the void will tend to resist further penetration. If the filler is injected in a single direction then the formations could be in the form of flaps which will be knocked over the openings by the flow of filler.

In any of the above soles it is desirable that the voids are aligned with cleats or wear formations on the undersurface of the sole.

The invention also includes a method of forming a sole, comprising moulding a sole in a mould having a plurality o projecting heads for defining voids within the sole, eac void having an opening in the upper face of the sole, defined by the neck of the heads, and forming means for preventing penetration of a filler, adhesive or the like into the voids during the attachment of the sole to an upper. The invention still further includes a sole formed by such a method or an article of footwear incorporating a sole as defined above.

Although the invention has been defined above, it is to be understood that it includes any inventive combination of the features set out above or in the following description.

The invention may be performed in various ways and a specific embodiment will now be described, by way of example, with reference to the accompanying figures, in which: Figure 1 is a scrap cross-sectional view of the under portion of an article of footwear;

Figure 2 is a view of a single tread of the sole of Figure 1 with a protective seal; and

Figure 3 is a corresponding view of Figure 2, on an enlarged scale, but showing a still further sealing arrangement.

A section of the lower part of a piece of footwear is generally indicated at 10. This comprises a high density sole portion 11 and an upper 12, having an insole 12a, which are adhered together by a filler 13 , such as low density polyurethane, injected when the sole portion 11 and upper 12 are in a mould. It is important that the sole portion 11 is highly elastic, at least just after moulding.

The high density portion defines a number of air voids 16 each of which has an upper opening 17, forming by the necks of the heads of the moulding tool used to define the voids during the moulding of the high density material. The high elasticity mentioned above means that the sole portion 11 can be peeled from this multiheaded tool with ease.

If the sole portion 11 was then simply adhered to the lasted upper 12,12a by the injection of the filler 13, the voids 16 would become filled with filler 13. The Applicants have realised that by sealing off the openings 17 at this stage they can achieve the energy storing construction mentioned above.

This sealing, which need not unnecessarily be total, can be effected by the provision of a scrim 18 (see Figure

1) , by plugging the openings 17 with plugs 18a which may be in the form of plastics plugs or hot glue or plastic (Figure

2) or by providing a self sealing formation at each opening such as illustrated at 19 in Figure 3. in this last example a cone 20 surrounds the opening 17. This cone 20 is compressed by the application of the lasted upper 12, 12a and closes off the opening 17. Additionally or alternatively when the filler is injecting it acts on the face 21 causing the cone to pinch the opening 17. Other formations, which react to the force of the upper or the injection or heat of the filler could be used.

If plastics plugs 18a are used, they may be mounted on carriers in lines or grids to provide for ready and speed location. A layer of foam is an alternative to the scrim 18.

It is to be understood that the term sole in this specification covers sole portions e.g. heels if these are manufactured independently of the rest of the sole.

Claims

1. A sole having a plurality of sealed air voids.

2. A moulded sole having an array of air filled voids eac with an opening extending to the upper face of the sole an means for preventing penetration of filler, adhesive or th like into the sole during attachment to the sole or upper.

3. A sole as claimed in Claim 2 wherein the penetratio preventing means comprise a plug of material for each opening.

4. A sole as claimed in Claim 3 wherein the plugs are interconnected.

5. A sole as claimed in any one of Claim 3 or Claim 4 wherein the plugs are interconnected.

6. A sole as claimed in Claim 2 wherein the penetration preventing means comprises a covering, scrim or insert for the openings.

7. A sole as claimed in any one of Claims 3 to 6 wherein the plugs, scrim, covering or insert are mounted on an upper.

8. A sole as claimed in Claim 2 wherein the penetration preventing means includes a formation moulded on the sole adjacent or circumjacent each opening and formed such that either they are deformed or deflected by application of a lasted upper on the sole and/or the pressure of the filler, adhesive or the like causes the formation to close of restrict the respective opening.

9. A sole as claimed in Claim 8 wherein the formation is generally conical and surrounds and defines the opening.

10. A sole as claimed in any one of the preceding claims having cleats or other wear formations on its under surface and wherein the voids are aligned with the cleats or formations.

11. A sole substantially as herein before described with reference to the accompanying drawings.

12. A method of forming a sole, comprising moulding a sole in a mould having a plurality of projecting heads for defining voids within the sole, each void having an opening in the upper face of the sole, defined by the neck of the heads, and forming means for preventing penetration of a filler, adhesive or the like into the voids during attachment of the sole or upper.

13. A method substantially herein before described with reference to the accompanying drawings.

14. A sole formed by the method of Claims 11 or 12.

15. An article of footwear incorporating a sole as claimed in any one of Claims 1 to 11 or Claim 14.