GB2320412A

GB2320412A - A sole for a boot or shoe

Info

Publication number: GB2320412A
Application number: GB9626790A
Authority: GB
Inventors: Stanley James; Ian Michael White; Brian Charles Pitcher
Original assignee: AIRWAIR Ltd; R Griggs and Co Ltd
Current assignee: AIRWAIR Ltd; R Griggs and Co Ltd
Priority date: 1996-12-23
Filing date: 1996-12-23
Publication date: 1998-06-24
Anticipated expiration: 2016-12-23
Also published as: GB9626790D0; GB2320412B

Abstract

A sole 2 of moulded plastics material, eg PVC, has a sole portion 2a and heel portion 2b contiguous therewith. The upperside of the sole 2 is recessed 4 to accommodate a foam insert 3 extending over substantially the whole length and width of the sole 2 so as, in use, to reduce the weight and increase the flexibility and comfort of the sole 2. This enables the provision of a chunky or platform sole of PVC without the consequent weight and rigidity.

Description

A Sole for a Boot or Shoe The present invention relates to a sole for a boot or shoe, and a boot or shoe having such a sole.

In the well-known DR MARTENS (Registered Trade Mark) boot or shoe, a PVC sole is heat welded to a PVC welt stitched to a lasted supper. For this purpose, the lower periphery of the lasted upper is turned inwardly to form an inwardly and downwardly directed peripheral flange. Downwardly extending ribs on an insole maintain the flange in an inwardly and downwardly extended position during stitching of the PVC welt through the upper. The PVC sole is then heat sealed to the welt. This is known as a "Goodyear" welted construction.

The upperside of the sole portion of the PVC sole of a DR MARTENS boot or shoe is partly recessed to accommodate a shallow foam insert, typically having a thickness of about 7 mm, to provide cushioning of part of the sole portion adjacent, in use, the ball of the foot of the wearer.

PVC is a high-density material, and therefore is extremely heavy for soles for boots and shoes. To reduce this weight, it is standard practice to provide both upstream and down-stream of the shallow sole insert a plurality of cavities between upstanding webs connecting opposite sides of a peripheral side wall of the sole.

However, PVC is extremely hard wearing, and therefore the actual thickness of the sole (excluding the tread and peripheral wall) need only be about 4 mm. When the peripheral wall is taken into account, the thickness of the sole is typically 9 mm, and of the cleat or tread is typically 2 to 3 mm.

Until now it has not been possible to form "chunky" soles of PVC, because such soles would be far too heavy. If fashion requires "chunky" soles, a material other than PVC must be chosen. Therefore, it has not been possible to provide DR MARTENS boots or shoes with "chunky" or "platform" soles. Such a sole would weigh well over 1 kg and would be prohibitively heavy.

An object of the present invention is to provide a sole suitable for a DR MARTENS boot or shoe which will allow chunky or platform soles without resulting in a boot or shoe which is prohibitively heavy.

The invention provides a sole as claimed in Claim 1. Such a sole when made of PVC is not prohibitively heavy and provides flexibility and comfort for the wearer.

The invention further provides a sole assembly comprising such a sole with a said foam insert glued into the recessed upperside of the sole.

Furthermore, the invention provides a boot or shoe having such a sole assembly.

An embodiment of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is a vertical longitudinal section taken along the line I-I of Figure 2 through a sole in accordance with the invention with a foam insert accommodated in the recessed upperside of the sole; Figure 2 is an underside view of the sole of Figure 1; and Figure 3 is a plan view of the sole of Figure 1; Figure 4 is a section taken along the line IV-IV of Figure 3; and Figure 5 is a section taken along the line V-V of Figure 3.

In the drawings, particularly in Figure 1, a sole assembly 1 comprises a sole 2 having a sole portion 2a and a heel portion 2b, and a foam insert 3. The upperside of the sole is recessed at 4 over substantially the whole length and width of the sole to accommodate the foam insert 3.

The sole 2 is of the "chunky" type and has a deep cleat or tread 5. The outer depth of the sole may be considerable, eg 30 mm or more at the sole portion 2a (and therefore at the toe 6) and over 40 mm (eg 43 mm) at the heel portion 2b (and therefore at the heel 7) . The actual thickness 8 of the sole 2 from the recessed portion 4 to the beginning of the tread 5 need be no greater than the usual thickness in the standard DR MARTENS sole, eg 4 mm. Typically, the depth of the cleat or tread 5 is approximately 7mm.

The provision of a recessed upperside 4 results in a peripheral upstanding wall 10, which may project substantially above the recessed upperside 4 eg by 10 to 25 mm, perferably by 16 mm at the sole portion 2a, and by 20 to 40 mm, preferably by 32 mm at the heel portion 2b. Depending on the desired degree of "chunkiness" of the sole, the height of the upstanding peripheral wall 10 may be even greater. The thickness of the upstanding peripheral wall 10 is preferably 10 to 20 mm, preferably about 14 mm.

The foam insert 3 may be formed of polyurethane foam, foam rubber or EVA (ethyl vinyl acetate) foam. The density of the foam insert 3 is preferably less than 0.5 g/cm3 with an IRHD test (International Rubber Hardness Depression) of 25 to 35". Typically, the density of the foam insert 3 is 0.2 g/cm3 with an IRHD test of 30". Thus, the foam insert 3 is extremely light, and enables the weight of a solid PVC sole to be reduced by a factor of three or more. As can be seen from Figures 1, 4 and 5, the depth of the foam insert 3 at its periphery is slightly less (about 3 mm) than the depth of the recessed upperside of the sole so that the upper surface 11 of the foam insert 3 is marginally below the upper surface 12 of the peripheral wall 10 of the sole. This provides clearance for a hot blade inserted between the upper surface 12 of the wall 10 and the welt of a shoe or boot upper (not shown) during heat sealing of the sole to the upper.

This avoids contact of the inserted hot blade with the material of the foam insert, which could result in the emission of pungent, and even poisonous gas.

As can be seen from Figures 1,4 and 5 the foam insert 3 (apart from the upper peripheral surface 11) projects above the upper surface 12 of the wall 10 to locate the sole assembly 1 relative to the welted upper (not shown) before heat sealing therebetween. Typically, the foam insert 3 extends by a height 13 of about 5 mm above the upper surface 12 of the peripheral wall 10 of the sole 2.

The sole insert 3 has a plurality of bores 14 extending between the top and bottom thereof. The bores 14 in the embodiment as shown are each provided with a countersunk portion 15 at the lower surface of the foam insert 3. The countersunk portions 15 may be tapered outwardly towards the bottom of the foam insert 3, and the top 16 of the bores 14 may be cylindrical as shown. The bores 14 may have any other suitable shape. The bores 14, which are not necessarily essential to the invention, provide an air-pumping action to the through-sole of the welted upper (not shown), which helps to keep the foot of the wearer cool.

The foam insert 3 should be fixed within the recessed upperside 4 of the sole 2 by adhesive along the periphery of the foam insert so as to prevent a gap forming between the upstanding wall 10 of the sole 2 and the foam insert 3. Preferably, the underside of the foam insert 3 is also fixed to the sole 2 also by adhesive. This prevents sole "bagging", ie sinking of the sole. The sole assembly 1 is attached to a welted upper (not shown), which may be of the typical DR MARTENS form. After heat sealing, the peripheral edge of the sole 2 together with the welt of the welted upper may be provided with the distinctive DR MARTENS grooves.

Such a shoe gives the appearance of having a chunky PVC sole without the consequent weight of a solid PVC sole. Furthermore, the foam insert 3 provides substantial flexibility and comfort, which is surprising for such a chunky PVC sole.

Claims

Claims:

1. A sole of moulded plastics material having a sole portion and a heel portion contiguous therewith, wherein the upperside is recessed to accommodate a foam insert extending over substantially the whole length and width of the sole so as, in use, to reduce the weight and increase the flexibility and comfort of the sole.

2. A sole as claimed in Claim 1 and made of PVC.

3. A sole as claimed in Claim 1 or 2, wherein the underside of the sole and heel portions has an integral cleat or tread.

4. A sole as claimed in any one of the preceding claims, wherein the sole has an upstanding peripheral wall defining the outer boundary of the recessed upperside.

5. A sole as claimed in Claim 4, wherein the thickness of the upstanding wall is substantially 10 - 20 mm.

6. A sole as claimed in Claim 4, wherein the thickness of the upstanding wall is substantially 14 mm.

7. A sole as claimed in Claim 4,5 or 6, wherein the height of the upstanding wall above the recessed upperside at the sole portion is substantially 10 - 25 mm.

8. A sole as claimed in Claim 7, wherein the height of the upstanding wall above the recessed upperside at the sole portion is substantially 16 mm.

9. A sole as claimed in any one of Claims 4 to 8, wherein the height of the upstanding wall above the recessed upperside at the heel portion is substantially 20 to 40 mm.

10. A sole as claimed in Claim 9, wherein the height of the upstanding wall above the recessed upperside at the heel portion is substantially 32 mm.

11. A sole as claimed in any one of the preceding claims, wherein the thickness of the recessed sole portion is substantially 4 mm.

12. A sole as claimed in any one of the preceding claims, wherein the thickness of the recessed heel portion is substantially 4 mm.

13. A sole assembly comprising a sole as claimed in any one of the preceding claims with a said foam insert glued into the recessed upperside of the sole.

14. A sole assembly as claimed in Claim 13, wherein the foam insert is polyurethane foam.

15. A sole assembly as claimed in Claim 13, wherein the foam insert is foam rubber.

16. A sole assembly as claimed in Claim 13, wherein the foam insert is ethyl vinyl acetate foam.

17. A sole assembly as claimed in any one of Claims 13 to 16, wherein the foam insert has a density of less than 0.5g/cm3 with an IRHD test of 25 to 35 .

18. A sole assembly as claimed in Claim 17, wherein the foam insert has a density substantially 0.2g/cm3 and an IRHD test of substantially 300.

19. A sole assembly as claimed in any one of Claims 13 to 18, wherein the foam insert has a plurality of bores extending therethrough between the upper and the lower surface of the insert.

20. A sole assembly as claimed in Claim 19, wherein the bores are countersunk in the underside of the insert.

21. A sole assembly as claimed in any one of Claims 10 to 16, wherein the insert has a peripheral portion with an upper surface below the upper surface of the sole so as to reduce the risk of contact of a hot blade with the insert during heat sealing of the sole assembly to a welted upper.

22. A sole assembly as claimed in Claim 21, wherein the insert has a portion within the peripheral portion and extending above the upper surface of the sole to locate the sole assembly in a welted upper.

23. A sole assembly substantially as herein described with reference to the accompanying drawings.

24. A boot or shoe having a sole assembly as claimed in any one of Claims 13 to 23, heated-welded to a said welted upper.

25. A boot or shoe as claimed in Claim 24, wherein the edge of the sole and of the welted upper is grooved for decorative effect.

26. A boot or shoe as claimed in Claim 24 or 25, wherein the edge of the welted upper is a different colour from the edge of the sole so as to produce a two-tone effect along the edge of the boot or shoe.