Manufacture of insole assemblies

Abstract

 An insole assembly comprises an insole 11, 12 the forepart 11 of which is flexible and has a central aperture, leaving a lasting margin, and a layer of resilient plastics foam material 22 extending over the full area of the top face of the insole and filling the central aperture and adhering to the insole in the forepart area 11 thereof. The upper surface of the foam layer is preferably covered by a flexible sheet material 19 trimmed to the profile of the insole in the forepart area and having its margin secured to the undersole of the foam layer in the rear part 12 of the insole.

Description

[0001] This invention relates to the manufacture of insole assemblies for shoes and has a particularly useful but not exclusive application in relation to women's fashion shoes, whereby any provision for underfoot cushioning tends to increase the internal height of the forepart of the finished shoe and to detract from the appearance of the shoe.

[0002] According to this invention there is provided an insole assembly comprising an insole having a forepart which is flexible and which has a central aperture leaving a margin for lasting about the periphery of the forepart, and a moulded layer of resilient plastics foam material extending over the full area or substantially the full area of the top face of the insole and filling said central aperture, said material being adherent to the insole in said forepart area thereof.

[0003] Said material may be non-adherent to the insole in the heel region thereof during the moulding of the material, for adhesion to the heel region of the insole subsequently.

[0004] According to a preferred feature of the invention a covering of sheet material extends over the layer of plastics foam material. Preferably the sheet material is trimmed to the shape of the insole in the forepart of the insole and has a marginal portion in said heel region where the foam material in non-adherent to the insole, which marginal portion is bonded to the underside of the layer of foam material.

[0005] The invention also provides a method of making an insole assembly comprising forming an insole which is flexible in at least its forepart area, and which has an aperture in said forepart area leaving a margin for lasting about the periphery of the forepart, and forming a layer of resilient foamed plastics material extending over the full area or substantially the full area of the upper surface of the insole, said plastics material filling said aperture and being secured to said upper surface of the insole in said forepart area thereof.

[0006] This invention further provides the following description of one embodiment of the invention. The description makes reference to the accompanying diagrammatic drawings in which:

Figures 1 and 2 are respectively side and plan views illustrating an initial stage in the manufacture of an insole assembly according to the invention,

Figures 3 and 4 are respectively a sectional side elevation and a plan view (partly cut away) showing the assembly including the insole of Figures 1 and 2 in the base part of a mould for the next stage in the manufacture of the assembly,

Figure 5 is a sectional side view of the insole assembly after its removal from the mould,

Figure 5A and 5B are respectively sectional views on the planes 5A-5A and 5B-5B of Figure 5,

Figure 6 is a view corresponding to Figure 5 and illustrating a characteristic of the finished assembly,

Figures 6A and 6B are respectively sectional views on the planes 6A-6A and 6B-6B of Figure 6, and

Figure 7 illustrates the method of incorporating the assembly in a shoe.

[0007] Referring just to Figures 1 and 2, a composite insole 10 is made comprising a flexible forepart 11, formed from any suitable material such as is conventionally used for the purpose, and a substantially rigid rear part 12 made from a suitable board material. If desired, a stiffening shank may be secured to the underside of the rear part. The two parts are scarfed and bonded together at 13 in the conventional manner. An aperture 14 is cut in the forepart 11, leaving a margin 15 of the material along the periphery of the forepart for lasting purposes.

[0008] The aperture insole 10 is then placed in the base part 17 of a mould as shown in Figures 3 and 4 and a metal shim 18 is placed on top of the rigid rear part 12. A cover 19 shaped from a piece of decorative sheet plastics material, the outline of which is indicated at 20 in Figure 4, is placed over the shim and the exposed forepart 11 and extends beyond the mould cavity in the base. The lid of the mould (not shown) has a shallow recess in its underside which accommodates the projecting edge portion 21 of the cover when the lid is placed on the mould. The cover has a wider projecting edge portion about the rigid rear part 12 than about the flexible forepart of the insole, as shown. A polyurethane foam is then injected into the mould between the cover 19 and the forepart 11 and shim 18 so that the polyurethane fills the cavity formed by the aperture 14 in the forepart 11 and forms a shaped footbed layer 22 over the forepart 11 and the shim 18. The polyurethane adheres stongly to the forepart and to the underside of the cavity 19, but not to the shim. Thus when the polyurethane has cured and the assembly is extracted from the mould, the shim can be removed and the rearward parts 23 of the footbed formed by the polyurethane foam are unattached to the board material.

[0009] The projecting edge portions 21 of the cover 19 are then folded under and bonded to the undersurface of the cover in the rearward portions and are trimmed back to the edge of the forepart.

[0010] The profile of upper surface of the foam footbed shaped by the mould lid is convex in the forepart area reducing to zero or nearly zero thickness at the edges of the insole as shown in Figure 5A, but is concave in the rearward area as shown in Figure 5B, conforming to the contour of the sole of the foot. The bottom face of the part of the footbed in the aperture is flush with the bottom face of the forepart.

[0011] In manfuacture of a shoe, the upper 24 is lasted to the insole part of the assembly in the normal way and the outsole 25 and then the heel 26 are secured to the insole. The heel is secured by heel nails 27 driven through the board material as shown in Figure 7. The rear part 23 of the footbed is finally bonded to the board material and so conceals the nail heads.

[0012] The construction is thus highly advantageous in that the filling of the aperture in the forepart with resilient plastic foam provides a cushioning body of resilient material under the major part of the forepart of the foot without causing a commensurate increase in the internal height of the correspoding part of the shoe. To assist in achieving maximum cushioning effect it is preferred to make the aperture 14 as big as is practicable while leaving the forepart with adequate mechanical strength and a sufficiently wide margin to permit normal lasting. The effective replacement of the foregoing material in the aperture area by the footbed material gives a good cushioning effect but at the same time improves the flexibility of the shoe. Also, ensuring that the rear part of the footbed does not adhere to the board material during manufacture of the insole assembly enables the heel nail heads to be concealed, and when the rear part 23 of the footbed is bonded to the board material, an extremely neat and finished appearance is obtained.

[0013] Instead of a shim it may be preferred to use a board material with a suitable coating which prevents the polyurethane from adhering to the board material. The cover material may if desired be omitted or may be bonded to the top surface of the polyurethane in a finishing operation.

Claims

1. An insole assembly comprising an insole having a forepart which is flexible and which has a central aperture leaving a margin for lasting about the periphery of the forepart, and a moulded layer of resilient plastics foam material extending over the full area or substantially the full area of the top face of the insole and filling said central aperture, said material being adherent to the insole in said forepart area thereof.

2. An insole assembly as claimed in claim 1, further comprising a covering of sheet material extending over the layer of plastics foam material.

3. An insole assembly as claimed in claim 2, wherein the foam material is non-adherent to the insole in the heel region thereof, the sheet material being trimmed to the shape of the insole in the forepart region of the insole and having a marginal portion in said heel region where the foam material is non-adherent to the insole, which marginal portion is bonded to the underside of the layer of foam material.

4. A method of making an insole assembly comprising forming an insole which is flexible in at least its forepart area, and which has an aperture in said forepart area leaving a margin for lasting about the periphery of the forepart, and forming a layer of a resilient foamed plastics material extending over the full area or substantially the full area of the upper surface of the insole, said plastics material filling said aperture and being secured to said upper surface of the insole in said forepart area thereof.

5. A method as claimed in claim 4, wherein the layer of foamed plastics material is non-adherent the upper surface of the rearward area of the insole.

6. A method as claimed in claim 4, wherein the foamed plastics material is moulded in situ on said forepart.

7. A method as claimed in claim 4, wherein a covering of sheet material is placed to extend over the layer of foamed plastics material.

8. A method as claimed in claim 7, wherein a marginal portion of the sheet material on the rearward area of the insole is secured to the underside of the plastics material.

9. A shoe comprising an upper, an insole assembly, a sole unit secured to the underside of the insole assembly, and a heel secured to the underside of the sole unit, said insole assembly comprising an insole having a forepart which is flexible and which has a central aperture therein leaving a margin to which the upper is lasted, and a moulded layer of resilient plastics foam material filling said aperture which material covers the top surface of the insole, and a covering of sheet material extending over the plstics foam material.

10. A shoe as claimed in claim 9, further comprising a fastener extending through the insole and the sole into the heel to secure the heel to the sole, and the sheet material having in its portion covering the rearward areas of the insole a margin which is bonded to the underside of the foam layer.

Drawing