GB2497103A

GB2497103A - Shoe with insole of varying hardness

Info

Publication number: GB2497103A
Application number: GB1120659.6A
Authority: GB
Inventors: Mark Farndon
Original assignee: MADISON TRADING Ltd
Current assignee: MADISON TRADING Ltd
Priority date: 2011-11-30
Filing date: 2011-11-30
Publication date: 2013-06-05
Also published as: GB201120659D0

Abstract

There is described a shoe 1 having an upper 2, a sole 3 and an insole (10, fig. 2). The insole 10 is formed from cushioning materials of two different hardnesses, and has a region of reduced hardness extending from the heel to the waist of the insole, on the medial side. The insole if preferably compression moulded elastomeric material having a thickness of from 5-15mm at the heel, and 2-5mm at the forepart. A method of manufacturing such a shoe, which may be a fashion shoe, using a modified last is also described.

Description

The present invention relates to shoes, and is particularly concerned with fashion shoes, insoles for fashion shoes, and methods for their manufacture Fashion shoes, in particular ladies' fashion shoes, are designed with much emphasis on aesthetic criteria1 to provide a shoe which will look attractive to the customer. In order to avoid bulkiness in such shoes, the sole structures of fashion shoes are conventionally made as thin as possible. To provide durability to such thin soles, hard-wearing materials are used and these materials have very little cushioning effect between the wearer's foot and the ground.

When the user walks or runs on hard surfaces such as paved areas or hard floors, the absence of cushioning within the shoes, particularly under the heel, causes significant loads at each step. The harder materials of the thin soles lead to these loads being applied suddenly to the wearer's foot. Studies have shown that peak impact loads of up to several times the wearer's body weight may be applied to the heel, and from there to the lower limb joints and ultimately to the spine.

This problem has been observed in athletic and training shoes, and is conventionally overcome by the use of soft cushioning materials for the soles or midsoles, and the use of cushioning insoles in the shoes. However, the use of such soft materials leads to a very thick and bulky shoe sole structure, which does not meet the aesthetic requirements of fashion shoes.

In athletic and training shoes, insoles having regions of different hardness have been proposed, with a harder area under the wearer's instep arch area to provide support to the medial arch. Such harder areas do not however extend to the heel of the shoe, because in this area relatively softer cushioning material is required to reduce shocks on the wearer's feet and legs during running or other activity.

Cushioning materials have been used in fashion shoes as cushioning insoles, formed from a thin sheet of cushioning material shaped to fit inside the shoe.

The aesthetic requirements of such shoes mean that the maximum thickness of the cushioning insoles is typically no more than 3 or 4 mm. While potentially reducing the jarring effect somewhat, significant peak impact loads are still experienced by the wearer. To provide support for the instep, it *has been proposed in fashion shoes to position a "cookie", which is a shaped piece of soft cushioning material, under the instep area of the wearer's foot. The "cookie" again does not extend to the heel part of the shoe but is located only under the arch of the foot.

There is therefore a need to provide, in a fashion shoe, a cushioning layer adequate to reduce impact loading on heel strike.

Gait studies have shown that when a wearer's foot impacts the ground during walking, the point of impact is at the lateral side (i.e. the "outside") of the heel. This sudden impact on the outside part of the heel causes the foot to rotate until the heel is flat on the ground, and in conventional fashion shoes with little or no cushioning this rotation is sudden and places high loads on the ankle joint. Prolonged walking in such shoes can lead to discomfort.

The present invention seeks to provide fashion shoes which, while remaining aesthetically attractive, provide in the heel area a cushioning structure which reduces the impact loads felt at heel strike, and which reduces the stresses produced in the sudden Coot rotation on heel strike, to ease the transition between the angled position of the foot on heel strike and a flat position of the foot on the ground during the step.

It has hitherto not been thought possible in the industry to produce a fashion shoe which is aesthetically acceptable and provides the amount of cushioning needed to reduce impact load.

If a thick cushioning insole is placed in a fashion shoe made on a conventionally-shaped last, the volume within the shoe which is available to accommodate the wearer's foot is reduced and the heel of the shoe may not extend sufficiently far up the wearer's heel to keep the shoe in place. However, if the size of the last is increased to provide additional volume within the shoe to accommodate a thicker layer off cushioning material, then the appearance of the upper may become bulky and aesthetically unattractive. If the height of the heel is such as to extend too far up the wearer's foot, it may cause pressure on the Achilles tendon leading to irritation or injury.

The present invention seeks to provide a method of manufacturing a fashion shoe with an insole of sufficient thickness to effectively reduce impact loads.

Another objective of the invention is to promote a controlled forward movement of the centre of pressure point during a stride, by the use of different hardness is of cushioning material at the heel area.

Measurements taken to plot the path of the centre of pressure beneath a person's foot during walking have shown that at the initial impact point, the centre of pressure is spaced from the centreline of the foot, and after the initial impact moves rapidly towards the centreline without progressing significantly forward along the foot. During the next phase of the step, the centre of pressure follows an arcuate course moving first forwardly and outward and then forwardly and inward until the centre of pressure reaches the toe-off point, essentially on the centreline of the foot print.

Measurements have shown that, by placing softer cushioning material at the medial side of the heel region, the locus of the centre of pressure can be made more closely to follow the locus of the centre of pressure during barefoot walking.

According to a first aspect of the present invention, there is provided a shoe comprising an upper, a sole attached to the upper, and an insole, wherein the insole has a first region extending from the heel to the toe of the insole on the lateral side formed from a material of a first hardness, and a second region extending on the medial side of the insole from the heel to the waist region of the insole formed from a material of a second hardness less than the first hardness.

A second aspect of the present invention provides an insole for a shoe, wherein the insole is formed from a layer of resilient material and has a first region extending from the heel to the toe of the insole on the lateral side formed from a material of a first hardness, and a second region extending on the medial side of the insole tram the heel to the waist region of the insole formed from a material of a second hardness less than the first hardness.

A third aspect of the invention provides a method for the manufacture of a shoe to accommodate the cushioned insole -Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a side view of a ladies slab heel" court shoe according to the present invention; Figure 2 is a longitudinal sectional view of the shoe of Figure 1; Figure 3 is a sectional view along the line 111-Ill of Figure 2; Figure 4 is a side view of a cushioning insole according to the invention; Figure 5 is an underneath plan view of the insole of

B

Figure 3; Figure 6 is a sectional view along the line VI-VI of Figure 5, illustrating the disposition of the different hardnesses of the insole material in a first embodiment of the invention.

Figure GA is a sectional view similar to Figure 6, and illustrating an alternative arrangement for the different hardnesses of the insole material; Figure 7 is a sectional view similar to Figure 6 showing an alternative structure for the insole; Figure BA is a side view of an upper for an alternative design of shoe according to the invention; Figure 8B is a side view of a wedge sole for use with the upper of Figure BA; Figure BC is an underneath view of the wedge sole of Figure SB; Figures 9A, 9B and 9C are views similar to Figures BA, BB and BC showing an upper, and side and underneath views of a sole for a flat court shoe according to the invention; and Figure 10 schematically illustrates the modification S of a last for making shoes according to the invention.

Referring to Figures 1 to 3, there is shown a court shoe with a slab heel and a cushioned insole, according to the invention.

The shoe 1 comprises an upper 2 and a sole 3. The upper is formed from pieces of leather sewn together at a heel seam extending the height of the heel at the back of the shoe, and an instep seam 5 extending from the sole to the edge of the upper 2. The lower edge of the upper 2 is attached to the sole 3 by bonding and inwardly-turned lasting margin 6 of the upper 2 to the top surface of the sole 3.

The sole 3 is an integrally-moulded component. having a slab heel 7 and a relatively thin region extending forward from the heel to the toe end.

On the top surface of the sole 3, an insole board 4 of cellulosic or other suitable material is cemented or otherwise attached at its central region to the sole 3, with the edge regions of the insole board 4 overlying the lasting margin 6 of the upper 2.

positioned within the shoe 1 is a cushioned insole 10, overlying the insole board 4 on the top surface of the sole 3.

Referring to Figures 4 to 7, the cushioned insole is seen in greater detail. In Figure 4, there is shown a side view of the insole 10. The upper surface 11 of the insole has a central depression and raised side regions 12, to more accurately fit the sole of a wearer's foot.

The underside of the insole is seen in Figure 5. The outline 13 of the undersurface 14 of the insole 10 is arranged to correspond to the outline of the insole board 4 attached to the top surface of the sole 3 within the shoe 1. This outline is also the outline of the undersurface of a last on which the shoe is made, and which will be described in further detail below. At the waist and heel regions of the insole 10, side surfaces 12a and 12b of the insole are angled upwardly and outwardly from the undersurface of the insole, because at these points the upper 2 extends upwardly and outwardly from the sole 3 and insole board 4 assembly. On the medial side, the side surface l2a is angled less steeply than the side surface 121, on the lateral side of the insole. The side surfaces 12a and 12b of the insole engage the inner surface of the upper 2 adjacent the sole 3.

Figures 6, GA and 7 are sectional views of alternative embodiments of the insole, taken along the line VI-VI in Figure 5.

In the embodiments shown in Figures 5 to 7, the insole is formed from cushioning materials of two different hardnesses. The main part of the insole is constituted by a first region extending along the lateral or outside region of the insole at the heel, and across the entire forepart of the insole-This first region is formed from a harder cushioning material I-I. At the medial heel-to-waist region of the insole, in a second region bounded by the line B in Figure 5, the insole is formed from a softer cushioning material S. This second region may extend forwardly from the heel to the waist of the insole, typically extending at least 40% and up to 70% of the length of the insole. As illustrated in the figure, the second region S extends forward from the heel to about half way along the insole.

Typically, the softer cushioning material in the second region S will have a hardness in the range of from 44 to 50, preferably from 46 to 48, and most preferably about 47 on the Asker C scale. The harder cushioning material, in the first region H on the lateral side and forepart of the insole, may have a hardness in the range of from 49 to 55, preferably from 51 to 53, and most preferably about 52 on the Asker C scale. The insole is preferably formed by compression moulding the materials together. The insole is preferably formed from a resilient material such as EVA, polyethylene, polyurethane, or similar elastomeric materials.

In the embodiment shown in cross-section in Figure 6, the softer cushioning material S extends in a region adjacent the undersurface of the insole, while the entire upper surface of the insole is composed of the harder cushioning material. The softer cushioning material does not extend over the entire thickness of the insole in this embodiment.

In the embodiment shown in cross-section in Figure GA, the softer cushioning material S extends in a region adjacent the upper surface of the insole, while the entire undersurface of the insole is composed of the harder cushioning material H. The softer cushioning material S does not extend over the entire thickness of the insole in this embodiment.

In the embodiment shown in Figure 7, the softer cushioning material S extends for the complete depth or thickness of the insole at the medial heel-to-waist first region of the insole.

The area of softer material bounded by the line B is less resistant to downward pressure, i.e. it compresses more at the same level of pressure, than is the remainder of the insole. The softer region extends at the rear of the insole, to a point P either adjacent to, on, or to the lateral side of, the centreline CL of the insole. In use, when the wearer's heel strikes the ground, the wearer's foot is inclined so that the initial impact point I is typically towards the lateral side (the outside) of the heel. The insole is arranged so that the cushioning material at the typical impact point I is the harder material, in order to provide durability in use, and to provide resilience to attenuate the high initial impact force. Shortly after the initial impact, the force on the wearer's heel is spread across the width of the heel, and tends to rotate the foot into a flat position. The softer cushioning material at the medial side of the heel is more yielding under the foot, so that the wearer does not experience any secondary shock as the inside part of the heel contacts the ground, due to the soft cushioning material in that region of the heel.

As the step continues, and the centre of pressure moves forward along the foot, the softer cushioning material on the medial side tends to continue the rotation of the foot until the forepart of the sole is flat on the ground. The positioning of cushioning material on the medial side from the heel to the waist region of the insole has the effect of smoothing the transition from heel strike to the flat toot position.

The heel part of the insole is of a thickness of from about 6 to 15 mm, typically from 8 to 12 rum, and preferably approximately 10 mm. At the front part of the insole, the thickness is approximately 2 to 3 mm.

Such a thickness at the heel part of an insole is uncommon in ladies fashion footwear, because last designers find it difficult to accommodate such a thickness of cushioning material into fashion footwear without detracting from the aesthetic appearance of the footwear.

Figures 3 and 9 show alternative forms of shoe into which the cushioned insole may be placed. Figure SA illustrates in side view and upper for a court shoe with a wedge heel. Figures 8B and 8C show, in side view and underneath view, respectively, an integrally-moulded sole for a wedge-heeled court shoe.

Figure 9A illustrates in side view and upper for a court shoe with a flat heel. Figures 9B and 9C show, in side view and underneath view, respectively, an integrally-maulded sole for a flat-heeled court shoe.

Both of the shoes illustrated in Figures 8 and 9 are intended for use with the cushioned insole shown in Figures 4 to 7.

A further aspect of the present invention provides a method for manufacturing fashion footwear on a last, to provide space within the footwear to accommodate the relatively thick cushioned insole of the present invention.

In footwear manufacture, once the footwear designer has determined the shape of the shoe, a last is produced on which the upper of the shoe can be placed for attachment to the sole. The last is essentially a block shaped somewhat like a person's foot, but conforming with the interior shape of the shoe upper.

The lower edge of the upper is extended to form a "lasting margin" which in the manufacturing process is folded beneath the last so that the sole can be attached to the lasting margin by bonding, sewing, or any other conventional technique.

In the conventional methods for the manufacture of fashion shoes, a last conforming to the interior shape of the upper is produced, and an insole board whose outline conforms to the undersurface of the last is then placed on the undersurface. The shoe upper is then placed on the last and the lasting margin is folded to overlie the edge regions of the insole board on the undersurface of the last and is cemented to the insole board. A sole assembly is then attached to the lasting margin and the central region of the insole board, and the last is then removed from the shoe.

In the present method, a last maker first produces the last to conform to the interior of the shape of the shoe between the sole and the upper. The designer then decides the dimensions of the cushioning insole which will be placed within the shoe. Thickness is then added to the undersurface of the last, corresponding to the thickness of the insole at each region of the undersurface. The shoe upper is then produced, conforming to the outline of the last and providing a lasting margin which can extend beneath the undersurface of the last for the attachment of the sole.

The amount and distribution of thickness added to the undersurface of the last preferably corresponds not to the unstressed thickness distribution of the resilient cushioning insole, but to the thickness distribution of the insole when compressed by a predetermined amount corresponding to a representative weight of a wearer.

The modification of the last is illustrated in schematic form in Figure 10. When the form of the interior of the shoe has been determined, a last form is determined by the last maker. The undersurface 0 of the determined form corresponds to the interior of the desired shoe, i.e. the upper surface of the insole when it has been inserted into the shoe. When the shape of the cushioning insole has been determined, the last form 20 is modified by adding thickness to the undersurface of the last. This may be done by adding thickness corresponding to the uncompressed form of the insole, to arrive at a last profile shovm by the line IU. However, and more preferably, a thickness distribution corresponding to the hatched region M is added. This thickness distribution corresponds to the distribution of thickness over the area of the insole when it is compressed by forces representing the weight of a wearer standing on the insole, and results in a modification to the last form 20 which adds less thickness than the thickness of the uncompressed insole, so that the undersurface of the last form follows the line IC.

In designing the optimal form and size (length) of the last to fit a majority of the population, suitable modification must be made to ensure that the actual insole surface 0 (in Figure 10) has the optimal insole length value. This optimal value differs from the last bottom length measured from heel to toe along the surface IC in Figure 10 by about half a shoe size (approximately 4 mm). This length adjustment must be taken into account when providing the internal volume within the shoe to accommodate the cushioned insole.

Once the final form of the last has been determined, a last is produced for the manufacture of the shoe.

To manufacture a shoe using the last, an insole board is first placed on the undersurface of the last produced in accordance with the modified last form.

The upper is then fitted over the last, with the edge 21 of the upper in the desired position to form the shoe of the required shape and style. The lasting margin of the upper is then turned underneath and bonded to the insole board, and the sole is finally attached to the lasting margin of the upper and to the insole board, in the conventional way.

After the upper and sole are securely fixed together, the last 20 is removed and the cushioning insert (on the basis of whose shape the form of the last was modified) is placed inside the shoe, to complete the shoe structure.

Claims

<claim-text>Claims: 1. A shoe comprising: an upper; a sole attached to the upper; and an insole wherein the insole has a first region extending from the heel to the toe of the insole on the lateral side formed from a material of a first hardness, and a second region extending on the medial side of the insole from the heel to the waist region of the insole formed from a material of a second hardness less than the first hardness.</claim-text> <claim-text>2. A shoe according to claim 1, wherein the insole 13 is formed from a layer of resilient material having a thickness of from 5 to 15 mm at the heel part and from 2 to 5 mm at the forepart.</claim-text> <claim-text>3. A shoe according to claim 1 or claim 2, wherein the insole is compression rnoulded from elastomeric material, and wherein the first region has a hardness of from 44 to 50 on the Asker C scale, and the second region has a hardness of from 49 to 55 on the Asker C scale -* 22 4. A shoe according to any of claims 1 to 3, wherein the second region extends only partially through the thickness of the insole.5. A shoe according to claim 4, wherein the second region extends adjacent the upper surface of the insole 6. A shoe according to claim 4, wherein the second region extends adjacent the imdersurf ace of the insole.7. A shoe according to any of claims 1 to 3, wherein the second region extends through the entire thickness of the insole.8. A shoe according to any preceding claim, wherein the second region extends to the centreline of the insole at the heel end of the insole.9. A shoe according to claim any of claims 1 to 7, wherein the second region extends to the lateral side of the centreline of the insole at the heel end of the insole.10. A shoe according to any preceding claim, wherein the second region extends forward from the heel end of the insole f or up to 70% of the length of the insole.11. A shoe according to any preceding claim, wherein the sole is a sole assembly comprising an outer sole part and an insole board.12. A fashion shoe according to any preceding claim.13. An insole for a shoe, wherein the insole is formed from a layer of resilient material and has a first region extending from the heel to the toe of the insole on the lateral side formed from a material of a first hardness, and a second region extending on the medial side of the insole from the heel to the waist region of the insole formed from a material of a second hardness less than the first hardness.14. An insole according to claim 13, wherein the insole has a thickness of from 5 to 15 mm at the heel part and from 2 to S mm at the forepart.15. An insole according to claim 13 or claim 14, wherein the insole is compression moulded from S 24 elastomeric material, and wherein the first region has a hardness of from 44 to 50 on the Asker C scale, and the second region has a hardness of from 49 to 55 on the Asker C scale.16. An insole according to claim 15, wherein the first region has a hardness of from 46 to 48 on the Asker C scale.17. An insole according to claim 15, wherein the first region has a hardness of 47 on the Asker C scale.18. An insole according to claim 15, wherein the second region has a hardness of from 51 to 53 on the Asker C scale.19. An insole according to claim 15, wherein the second region has a hardness of 52 on the Asker C scale.20. An insole according to any of claims 13 to 19, wherein the second region extends only partially through the thickness of the insole.21. An insole according to claim 20, wherein the second region extends adjacent the upper surface of the insole.22. An insole according to claim 20, wherein the second region extends adjacent the undersurface of the insole.23. An insole according to any of claims 13 to 19, wherein the second region extends through the entire thickness of the insole.24. An insole according to any of claims 13 to 23, wherein the second region extends to the centreline of the insole at the heel end of the insole.25. An insole according to any of claims 13 to 23, wherein the second region extends to the lateral side of the centreline of the insole at the heel end of the insole.26. An insole according to any of claims 13 to 25, wherein the second region extends forward from the heel end of the insole for at least 40 of the length of the insole. * 2627. A method of manufacturing a shoe, comprising the steps of: determining the form of a cavity defined by the shoe upper and the shoe sole; determining the form of a shoe last to correspond to the cavity; determining a thickness distribution of a resilient insole; modifying the form of the shoe last to add to the undersurface of the last a thickness distribution corresponding to the determined thickness distribution of the insole; producing a shoe last in the modified form; and manufacturing a shoe using the last.28. A method according to claim 27, wherein the thickness distribution added to the undersurface of the last corresponds to the thickness distribution of the insole when compressed by a wearer's weight.29. A shoe substantially as herein described with reference to Figures 1 to 3, Figures BA to 8C, or Figures 9A to 9C of the accompanying drawings. S 2730. An insole for a shoe, substantially as described herein with reference to Figures 4 and 5, Figure 6, Figure 6A, or Figure 7 of the accompanying drawings.31. A method of manufacturing footwear substantially as described herein or with reference to Figure 10.</claim-text>