GB2398991A

GB2398991A - An insert for a shoe, boot or sandal

Info

Publication number: GB2398991A
Application number: GB0401522A
Authority: GB
Inventors: Kevin Bann
Original assignee: R Griggs and Co Ltd
Current assignee: R Griggs and Co Ltd
Priority date: 2003-01-23
Filing date: 2004-01-23
Publication date: 2004-09-08
Anticipated expiration: 2024-01-23
Also published as: GB2398991B; GB0301581D0; GB0401522D0

Abstract

An insert 2 for a sole 1 of a shoe, boot or sandal comprises two portions 3a, 3b. Each of the portions has projections 4a, 4b which interdigitate with the projections on the other portion, to provide a hinge which permits the insert 2 to flex roughly about a transverse axis, there being no direct connection between the two portions 3a, 3b apart from friction. This permits longitudinal movement of one portion 3a, 3b relative to the other. Suitable materials for the insert may be PVC, EVA and polyurethane.

Description

239899 1 An Insert for a Sole for a Shoe, Boot or Sandal

Backaround to the Invention

The present invention relates to an insert for a sole of a shoe. The general term 'shoe' will be used herein and includes a boot or sandal.

Any discussion of the prior art throughout the specification should in no way be considered as an admission of that such prior art is widely known or forms part of

common general knowledge in the field.

An insert for a sole of a shoe may be resilient, so as to provide cushioning and comfort, or it may be relatively stiff in order to provide rigidity. The nature of the insert will depend on the use of the shoe in which it is intended to be inserted.

It is not uncommon for a wearer of a shoe to find the shoe uncomfortable because there is insufficient flexibility in the sole to permit flexing of the foot. In some cases it is possible for the wearer of a shoe to achieve flexing of the foot, despite a relatively stiff sole but this tends to lead to damage of the sole.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

The Invention The invention provides an insert for a sole, boot or sandal as claimed in Claim 1 and in Claim 16, a sole as claimed in Claim 17 or 18 and a shoe, boot or sandal as claimed in Claim 19. Claims 2 to 15 set out preferred features of the invention.

Regarding the insert itself, the hinge enables the insert to flex without the top part having to compress and the bottom part expand, thus making flexing easier and saving energy. It is preferred that there should be a minimum of two or three projections so as to provide a stable hinge construction.

In a preferred embodiment, the hinge is adapted to be located in the region of a tread in the sole of the shoe in which the insert is intended to be placed.

In a preferred embodiment, the insert is made of polyvinylchloride (PVC).

Alternatively, the insert can be made of ethylene-vinyl acetate copolymer (EVA), polyurethane or metal such as stainless spring steel. The insert preferably contains holes to lighten it or to make it more resilient or for manufacturing convenience.

The specific gravity ofthe insert is preferably not more than about 1.15 g/cm3 and preferably not less than about 0.4 g/cm3. In a preferred embodiment, the specific gravity of the insert is between 0.7 and 0.75 g/cm3.

The Shore A hardness of the insert is preferably not more than about 65 and preferably not less than about 40 or 35. In a preferred embodiment, the Shore A hardness of the insert is 50 +5.

Preferred embodiment An embodiment of the invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the top of a sole having an insert according to a first embodiment of the present invention; Figure 2 is a vertical section along the plane II-II in Figure 1; Figure 3 is a perspective view of the underside of the fore insert of Figure 1; and Figure 4 is a perspective view of the heel insert of Figure 1.

Figure 5 is a perspective view of the top of a sole according to a second embodiment of the present invention; Figure 6 is a perspective view of a fore insert according to the second embodiment of the present invention; Figure 7 is a perspective view of a heel insert according to the second embodiment of the present invention.

The soles described below with respect to Figures 1-4 and Figures 5-7 may be used in a shoe, boot or sandal, in a manner known to the person skilled in the art.

Referring to the first embodiment shown in Figure 1, a sole I has a fore insert 2. The insert 2 has two portions 3a and 3b which are joined to one another by means of a hinge 4. The hinge 4 is in the form of a joint having interdigitated projections 4a and 4b.

However, the hinge 4 can be of any suitable configuration. The hinge 4 is arranged to permit flexing of the insert 2 roughly about a transverse axis. The hinge 4 shown extends across the sole l nearly perpendicular to the length of the sole 1; alternatively, the hinge 4 could extend at a greater angle to the perpendicular or could be substantially perpendicular to the length. It is useful, though not necessary, for the hinge 4 to coincide with a tread of the sole I or the ball of the foot, since this is usually the region of the sole 1 in which most flexibility is required. A small gap is left between the ends of the projections 4a, 4b so that when the sole 1 is flexed, sliding movement occurs between the portions 3a and 3b due to the difference in the bending radius of the sole 1 and of the insert 2. There is no direct connection between the two portions 3a, 3b apart from friction, though an indirect connection may be provided for instance by sticking a foot bed or felt on top, as referred to later. To retain the portions 3a, 3b in position relative to the sole 1, locating recesses 3c are formed in the portions 3a, 3b, engaged by projections la formed on the sidewalls ofthe sole 1.

The insert 2 has holes 5; the holes 5 reduce the weight of the insert and reduce the cooling time of the insert during manufacture.

The underside ofthe insert 2 has cavities 6 on a face engaging the sole 1. There can be any suitable number of cavities 6, depending on for instance the tread pattern. The cavities 6 contain air and are intended to achieve a cushioning effect, so that the sole 1 is more comfortable for the user. The cavities 6 are preferably arch-shaped, so that load on the insert 2 is distributed more effectively. The cushioning effect of the cavities 6 can be further improved by selecting an appropriate material, such as a resilient material, for the insert 2. For example, a blown PVC or a soft, plasticised PVC would provide adequate cushioning and would be a suitable material for the insert 2.

Alternative insert materials include EVA and polyurethane. The material of the insert 2 should have a Shore A hardness of not more than about 65 and not less than about 40 or 35, say about 50. The hardness of the insert can usually be altered in the manufacturing process, although this will depend on the material used. Similarly, the specific gravity of the insert can vary but it is preferable if it is in the range 0.7 to 0.75 g/cm3. The specific gravity of the sole 1 is preferably in the range 1.12 to 1.15 g/cm3.

It would alternatively be possible to include a metal insert 2 e.g. of stainless spring steel; this may be required as a protective layer if the shoe having the sole 1 were to be required for heavy duty use, for example, in a factory or on a building site. A metal insert 2 would not provide cushioning but the hinge 4 will permit flexing of the foot.

However, the metal insert 2 could be used in conjunction with a cushioned insert 2, if necessary.

It would be possible to include an insert 2 with more than one hinge in order to improve the flexibility of the insert, although it is likely to complicate the manufacturing process.

In the sole 1 shown, the insert 2 only extends over a fore portion 7 of the sole 1. It would be possible for the insert 2 to extend along the length of the sole 1, if required.

Similarly, more than one insert 2 could be included in the sole 1.

The drawings show a second insert 8 in the heel 9 of the sole 1. Between the fore insert 2 and the heel insert 8, the top of the sole l can be flat, as shown, or it can be provided with cavities, for instance a number of square cavities (as seen in plan), divided by relatively narrow walls.

Figures 5 to 7 show a second embodiment of a sole according to the invention. The design of the hinge part of the sole is identical to that shown in Figures I to 4 and will not be described further. Like reference numerals in Figures 5 to 7 indicate like parts to those shown in Figures I to 4. The sole of Figures 5 to 7 further includes a cushioning system. The insert comprises areas 10 of greater thickness in the direction normal to the sole and areas 11 of reduced thickness. A plurality of upstanding protrusions 12 are formed on the lower sole, each protrusion 12 engaging a respective reduced thickness area 11. Because of the reduced thickness where the insert contacts the protrusions and because of the resilient nature of the material of the insert, a spring like structure is formed. The provision of a plurality of such spring like structures over the area of the insert provides a cushioning effect.

The shoe (which may be in the form of a boot or sandal) can be made up in any suitable way. In doing so, a foot bed or felt for instance may be stuck along the top of the sole 1 and inserts 2 and 8. x x x

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

The present invention has been described above purely by way of example, and modifications can be made within the spirit of the invention.

Claims

CLAIMS: 1. An insert for a sole of a shoe, boot or sandal, the insert

comprising two separate portions, each of the portions having at least two projections which interdigitate with the projections on the other portion, to thereby provide a hinge between the portions so as to permit flexing of the insert roughly about a transverse axis, there being no direct connection between the two portions apart from friction, thus permitting longitudinal movement of one portion relative to the other.
2. An insert as claimed in claim I, and made of polyvinylchloride.
3. An insert as claimed in Claim 1, and made of ethylene-vinyl acetate copolymer.
4. An insert as claimed in Claim 1, and made of polyurethane.
5. An insert as claimed in any of the preceding Claims, wherein the insert contains holes.
6. An insert as claimed in any of the preceding Claims, wherein the specific gravity of the insert is not more than about 1.15 g/cm2.
7. An insert as claimed in any of the preceding Claims, wherein the specific gravity of the insert is not less than about 0.4 g/cm3.
8. An insert as claimed in Claim 6 or 7, wherein the specific gravity of the insert is between about 0.7 and about 0.75 g/cm3.
9. An insert as claimed in any of the previous Claims, wherein the Shore A hardness of the insert is not more than about 65.
l O. An insert as claimed in any of the previous Claims, wherein the Shore A hardness of the insert is not less than about 35.
11. An insert as claimed in Claim 9 or 10, wherein the Shore A hardness of the insert is approximately 50 +5.
12. An insert as claimed in Claim 1, and made of metal.
13. An insert as claimed in any of the preceding Claims, wherein the hinge is adapted to be located in the region of a tread in the sole in which the insert is to be inserted.
14. An insert as claimed in any of the preceding Claims, wherein the underside of the insert contains cavities in a face adapted to engage the sole in which it is to be inserted.
15. An insert as claimed in Claim 14, wherein the cavities are archshaped.
16. An insert substantially as herein described with reference to any one of the embodiments shown in the accompanying drawings.
17. A sole having an insert as claimed in any of the preceding claims.
18. A sole substantially as herein described with reference to any one of the embodiments shown in the accompanying drawings.
19. A shoe, boot or sandal having a sole as claimed in Claim 17 or 18.