WO2015092352A2

WO2015092352A2 - Improvements in or relating to footwear

Info

Publication number: WO2015092352A2
Application number: PCT/GB2014/000523
Authority: WO
Inventors: Claire Lilian BURROWS
Original assignee: Air & Grace Limited
Priority date: 2013-12-19
Filing date: 2014-12-19
Publication date: 2015-06-25
Also published as: GB201322629D0; EP3082488A2; GB201412185D0; PT3082488T; GB2521494B; DK3082488T3; EP3082488B1; ES2690387T3; WO2015092352A3; GB2521494A

Abstract

The present invention relates to footwear for humans and, more particularly, to an Insole, Inner sole or Insert sole member therefor. A fundamental requirement for footwear: boots, shoes, slippers and sandals alike Is that they are comfortable to wear. A shoe, in simple terms, comprises a sole, which treads upon the ground or floor in use, an Innersole, upon which the foot rests and through which motive forces are transmitted to the ground and an upper. The foot and body of the user of such shoes are subject to impressive forces when the heel strikes the ground. This impact is repeated numerous times while the user is walking. This repeated, high-energy Impact causes discomfort, not only in the heel of the foot, but also transferred throughout the body of the user of such shoes. Additionally, since the heel is elevated, the impact forces the foot forward in the shoe, jamming the toes against the front of the shoe to cause further discomfort. Foot pain Is not restricted to metatarsalgia and many foot conditions are due to poor shoe fit. Many shoes are provided with Insoles, which may differ in thickness about the sole, although typically have raised edges an in practice provide little by way of variation in thickness across the sole. The present invention seeks to provide an improved Insole, Inner-sole or sole Insert for a shoe which overcomes or ameliorate some of the problems found In modern day footwear, particularly those with a stiff sole or a high heel.

Description

Improvements in or relating to Footwear

Field of the Invention

The present invention relates to footwear for humans and, more particularly, to an insole, inner sole or insert sole member therefor.

Background to the Invention

A fundamental requirement for footwear: boots, shoes, slippers and sandals alike is that they are comfortable to wear. A shoe, in simple terms, comprises a sole, which treads upon the ground or floor in use, an insole, upon which the foot rests and through which motive forces are transmitted to the ground and an upper, which in the case of a boot enshrouds the upper part of the foot and extends above the ankle, in the case of a shoe enshrouds the front part of the foot and extends below the ankles, around the heel, yet in a sandal comprises a number of loops which enable the foot to pull the sandal with it as it is moved in an upward direction as the wearer takes steps, or longitudinally in the case of a shuffle.

Figure 1 shows the left and right feet 10 of a human walking without the aid of footwear and, with respect to the left foot, 11, shows how a human foot will naturally bend about the ball 16 of the foot during movement, the reference numeral 12 indicating the heel bone, 14 indicating the metatarsal bones and 14 indicating the plantar fascia ligament. Many modern shoes, including high-heeled fashion shoes are designed so that the heel of the foot wearing the shoe is higher than the toes. The heel of the shoe is typically formed of a hard plastic. The heel often is tapered so that the point of impact between the heel and surface is relatively small in cross-sectional area. Thus, the foot and body of the user of such shoes are subject to impressive forces when the heel strikes the ground. This impact is repeated numerous times while the user is walking. This repeated, high-energy impact causes discomfort, not only in the heel of the foot, but is also transferred throughout the body of the user of such shoes. Additionally, since the heel is elevated, the impact forces the foot forward in the shoe, jamming the toes against the front of the shoe to cause further discomfort. The onset-rate, that is the rate at which the impact occurs, wherein the forces are transmitted through hard narrow high heels, is typically very rapid. This rapid onset-rate does not allow time for the ankle, foot and leg muscles to adapt to the impact. This causes muscle and foot surface fatigue and increases vulnerability to twisting an ankle or other injuries.

Pain experienced under the ball of the foot (Metatarsalgia) occurs as a consequence of the five long foot bones (the metatarsals) dropping from weakened ligaments. This causes the entire anatomy of the forefoot to give way, leading to excessive pressure and chafing on the ball of the foot. At times the pain occurs in the region around the second, third or fourth toes. Typically, the pain worsens when standing, walking or running and improves with rest.

Metatarsalgia is a frequent occurrence in women wearing fashionable shoes that are too narrow and/or have medium to high heels. It often occurs in combination with excessive formation of callouses. Wearing narrow and/or high-heeled shoes worsens the pain. There are a number of reasons for ball of foot pain. One reason is an abrupt increase in a sporting activity. Other actions that bring on this pain include long periods of standing or walking in hard shoes and boots. The primary cause of this condition is wearing high heels, which forces 70-80% of your bodyweight onto the forefoot area. The carrying of too much body weight through obesity also places undue strain on the feet. However, ball of foot pain is not restricted to fashion minded women in tight fitting shoes. Many men and women endure ball of foot pain while wearing ordinary flat shoes.

Foot pain is not restricted to metatarsalgia and many foot conditions are due to poor shoe fit. Many shoes are provided with insoles, which may differ in thickness about the sole, although typically have raised edges and in practice provide little by way of variation in thickness across the sole. With many shoes, not necessarily being high-heeled, it will be appreciated that with a stiff sole, for walking, etc., pain will arise in a similar situation, since the foot will not be flexing in a manner that the foot is designed to flex. This can give rise to painful feet.

US2009139111 provides a cushioned inner sole for high-heeled ladies' shoes which provides and particularly to the field of providing comfort and stability in heeled shoes. US4972612 flexible high heel insert that is manufactured from a flat cushioning material. The insert generally has an adhesive back for placement in a high heel shoe. When the insert is placed in the shoe, an adhesive side of the rear portion is pressed into place in the heel area of the shoe, and the adhesive side of the tapering end portion is pressed against the inward side of the shoe so that the insert has an overall twisted configuration. US2005081401 provides high- heeled footwear with a heel with a resilient compressible element allowing the heel of the foot to be lowered at heel strike to approximate a normal walking pattern in low-heeled shoes. However, not all of these systems truly provide relief from foot pain.

Object to the Invention

The present invention seeks to provide an improved insole, inner-sole or sole insert for a shoe which overcomes or ameliorate some of the problems found in modern day footwear, particularly those with a stiff sole or a high heel. The present invention also provides a shoe with an improved inner-sole.

Statement of Invention

In accordance with a first aspect of the present invention, there is provided shoe insole, the insole being operably fitted to the whole area of an inside sole portion of a shoe, from a rearmost, heel portion to support a heel of a user of the shoe to a distal portion under the toes of a wearer of the shoe; the insole comprising three layers, wherein: a first layer comprises a heel section which extends from a rearmost portion, the heel section being sized and shaped to accommodate, in use, the weight/forces arising in use from the heel of a user of the shoe; a second layer, extending from the heel section to an area associated, in use, with a ball of the foot, where the distal edge of the second insole layer follows, generally, an angle subtended by the phalanges; and, a third layer which overlies the first and second layers, providing the only support for the phalanges, wherein, toward the edge of the distal edge of the second insole, the insole is chamfered and wherein the first second and third insoles are manufactured from foam in the ranges of, respectively, 40 - 50° Asker hardness; 20 - 30° Asker hardness; and 60 - 90° Asker hardness; and wherein: the first layer defines a lift, such that, in use, the load is spread about the heel and the user's heel is raised and whereby to provide an improved spinal alignment.

Preferably, the thicknesses of the layers lie in the following ranges, from first to third, respectively, 3 and 7 mm; 3 and 9 mm; and, 1 and 8 mm.

Conveniently, the material layers are of plastics foam and the layers have densities, from first to third, respectively, 0.13 - 0.17; 0.09 - 0.13; and 0.13 - 0.17 g /cm3.

Preferably, the layered materials are of plastics foam and the layers have a hardness value of, from first to third, respectively, 40 - 50; 20 - 30; and 70 - 80° Asker, preferably 45, 25 and 75° Asker, respectively.

Further preferably, the distal edge of the first insole is chamfered. With regard to chamfering of the first layer and second layer, the length of chamfering is dependent upon the length of the shoe and the chamfering can be provided up to a length of approximately 60 mm for larger shoe sizes, but is typically of the order of 25mm.

The arrangement of the distal edges of the first and second layers can be defined with reference to an insole longitudinal axis from heel to toe. The edges can be perpendicular to the axis. However, especially with respect the second layer; the amount of cushioning can be reduced along an outer peripheral edge and wherein the edge of the heel chamfer is substantially perpendicular to said axis. Nonetheless, the chamfering could also be tailored for a particular foot and shoe combination. In accordance with another aspect of the invention, the third layer of foam comprises a laminated layer having an additional layer of a harder foam which faces the second layer, the additional layer of foam being coextensive with the basic third layer and having a thickness in the range of 1 - 4mm, having a density in the range of 0.10 - 0.15 g/cm³, and a hardness in the range of 15 - 35° Asker C foam. Good results, for this lower layer have been provided with foam of a density of 0.11 g/cm³, 25° Asker hardness and a thickness of 2mm, together with an upper layer of 2mm in thickness. The present invention can assist in the modification of a shoe such that it is comfortable to wear and provides an insole that offers a potential solution to women and men who enjoy wearing fashionable footwear - and other types - but for the inside of the shoe.

Insoles in accordance with the present invention can allow the weight of the body to be dispersed more evenly across an entire foot instead of being focused on the relatively small area of a user's forefoot. The insoles avoid disproportionate weight distribution and chafing on the ball of the foot. The end-result is that pain and burning are reduced especially during times of extended standing or walking.

In accordance with another aspect of the invention, there is provided a shoe - meaning any type of footwear, such as a boot, a sandal, a slipper or a formal shoe having such a type of an insole.

Brief Description of the Figures

For a better understanding of the present invention, reference will now be made, by way of example only, to the Figures as shown in the accompanying drawing sheets, wherein :- Figure 1 shows the left and right feet of a human walking without the aid of footwear;

Figure 2a shows the underside of an insole in accordance with the present invention;

Figure 2b shows a side view and plan view of an insole in accordance with the present invention;

Figure 2c shows a cross-sectional view of a first shoe made in accordance with the invention;

Figure 2d shows a cross-sectional view of a second shoe made in accordance with the invention;

Figure 2e shows a cross-sectional view of a third shoe made in accordance with the invention;

Figure 3a shows a series of images of a biped walking;

Figure 3b shows a butterfly diagram;

Figures 4a and 4b provide an indication of forces that absorbed by a foot during walking; and

Figures 5a and 5b show how the bones of a foot absorb and react to forces involve in landing and in lift off during walking.

Detailed description of the Preferred Embodiments

There will now be described, by way of example only, the best mode contemplated by the inventor for carrying out the present invention. In the following description, numerous specific details are set out in order to provide a complete understanding to the present invention. It will be apparent to those skilled in the art, that the present invention may be put into practice with variations of the specific.

Referring now to Figures 2a and 2b, which Figures show, respectively, an underside of an insole - indicated generally at 20 - in accordance with the present invention and side and elevation views of the same. All components of the insole are provided in layers. Reference numeral 22 indicates a heel section insole layer - a first insole layer - which extends from a rounded rearmost portion towards a gradient section 23, the gradient section tapering in thickness to zero such that the heel section is sized and shaped to accommodate, in use, the weight/forces arising in use from the heel bone of a person wearing shoes equipped with the inner sole of the present invention. The length of the taper can vary up to around 25mm for a typical ladies shoe and can be half of the length of the layer, with respect to the overall length of the first and second layers. The heel section is comprised of a relatively stiff material and further defines a lift 21 such that, in use, the load is spread about the heel and the user's heel is raised. The lift provides a little extra height, between 10 and 18 mm, dependent upon the frame of the person. For a 65Kg, 1.60 tall person, a lift of 12mm has been found to provide sufficient comfort. The lift provides for an improved spinal alignment than compared to a completely flat shoe. It will be appreciated that provided the weight borne by the heel section is appropriately placed, it is not mandatory for all users of the insole to provide a gradient by chamfering of the heel sections. The heel is conveniently of a foam of 40° Asker hardness, for example a polyurethane foam, such as Ortholite foam 0.15D 45° Asker, of a 5mm sheet thickness. Heavier persons may require greater density foam to provide support and comfort.

There is a second insole layer 24, extending from the heel section to the area associated with the ball of the foot, where the edge of the second insole layer follows, generally, the angle subtended by the bones of the toe, the phalanges. The second or middle layer is chamfered, in a gradient section 25, at an angle to follow the line of the foot but ensures that there is a maximum of cushioning under the ball of the foot where it is particularly needed. The second or middle layer can comprise a softer foam, for example a polyurethane foam, such as Ortholite foam 0.11 g/cm³ density, 25° Asker hardness foam, of between a 3 and 9 mm sheet thickness, with especially good results being provided with thicknesses in the range 5 - 7mm. The additional cushioning of the second layer gradually reduces to zero under the joints of the toe where the extra padding is not required. The second layer extends from heel of the foot to the ball of the foot of a user. It has been found that instead of the chamfer being effectively perpendicular with respect to an axis of the foot running from the heel section to the front of the foot, the chamfer is preferably diagonally arranged in the range of 35°- 75° with respect to the axis to the outside of the body, conveniently 60°.

With regard to chamfering of the first and second layers, the length of chamfering is dependent upon the length of the shoe, bearing in mind that whilst a ladies UK size 1 (Eur 33) is 210mm, an adult male size 14 (Eur 49) can be some 320mm in length. The chamfering can be provided over a length of approximately 60 mm or greater for larger shoe sizes, but is typically of the order of 25mm for smaller ladies shoes, the angle of chamfer being of the order of 1° - 20°, being dependent upon the length of the chamfer portion and the thickness of the insole layer.

Underneath the phalanges, toward the edge of the insole exists only the third layer, comprising memory foam of a thickness of between 1 - 6mm in thickness, conveniently 2 mm provides an adequate degree of support, for the reduced weight bearing sections. The third layer can also comprise a lamination of two layers of sheet material, for example, in addition to a 2mm layer as described above, a further 2mm layer of 0.11 g/cm³ density 25° Asker hardness is provided, which slightly harder material is provided in contact with the second layer. This third layer, composite or otherwise, therefore provides what is commonly referred to as super soft memory foam, for example a polyurethane foam, for contact with the sole of the foot. The third layer overlies the first and second layers - lying from heel to toe and conveniently comprises a slow recovery foam of 0.15 g/cm³ density 70-80° Asker hardness foam 2mm sheets. That is to say, the centre layer is of medium firmness and the top layer is what is commonly referred to as soft memory foam, being a slow recovery foam. The materials are manufactured such that they lose no more than 5% of their shape over time.

The present invention, in one aspect combines a distinct layering of three distinct insole layers, which layers enable specific use requirements to be addressed, whereby the overall effect, for a wearer of shoes fitted with such insoles, is one of controlled cushioning and shock absorption.

The insole can be conveniently formed by using die cutting assemblies, although a laser cutting table can also be used, as will be known to those skilled. In the manufacture of the graduated sections, a linishing machine can be employed or a skiving tool, as is commonly used in footwear manufacturing, although other types of abrasive machines can obviously be employed. As is known, with materials such as leather and plastics used for insoles, skiving knives trim the thickness of sheets of leather and similar materials such as plastics, often around the edges, to thin the material and make it easier to work with. Conveniently, the separate layers of the insole can be glued together using appropriate adhesives, for example a latex adhesive, which can be applied by a roller device.

This insole, also referred to as a foot-bed, is somewhat thicker than a typical insole and it must be realised that it cannot be used with all footwear. It is essential that the shoe has enough room to accommodate the bulk of the foot-bed, since otherwise the upper part of the foot may be too closely spaced with respect to the upper, and whilst there will be provided underfoot comfort, this could be tempered by friction contact with the inside of the upper.

Figures 2c, 2d and 2e show three different types of shoe, boot and ballet shoe. It will be appreciated that the insole in accordance with the invention can be utilised in many different forms of footwear, across all ages, for use by male and females, with different densities selected for the differing weights/masses of the particular wearers of a shoe with such an insole.

Figure 3a shows a series of seven images of a biped walking, from touchdown of the right foot RF with the heel (3i) through lift-off (3iii), to approach to touch down (3vii). Reference is made to a butterfly diagram of Figure 3b which shows how forces vary as a foot makes contact with the ground in normal gait. Specifically, the butterfly diagram shows a sequence (in iso-spaced time frames) of force vectors (the lines), with their origins in the ground (the beginnings of the lines at the lower aspect of the diagram. The force vectors have a length (the magnitude of the force) and a direction (the inclination of the vector) and an origin in the ground. These diagrams are typically found in research in gait and are indicative for normal and abnormal gait. Of importance is the fact that these are typical, well-known patterns.

Reference to the gait cycle can provide some assistance in understanding the present invention and how the foot-bed provides shock absorption and cushioning at the three key stages: heel strike; mid stance; and push off. The foot-bed will cushion the impact and absorb the shock at heel strike. That's why the three layers and three densities are required at this point where the foot takes the most impact. Figures 4a and 4a show, respectively, how the heel lands upon a surface: the plan of the foot of Figure 4a shows how the main pressure points of the foot will land in mid- stance; Figure 5a shows that the heel absorbs most of the landing energy. Equally, Figures 4b and 5b show, respectively, views of the foot in perspective and sectional views, emphasising the presence of the bones within the foot, how the distal ends of the phalanges, namely the toes, bear upon the ground, absorbing most of the forces on push-off. Between landing and push-off, the foot rolls through to mid stance. Where the impact is less, but the cushioning is still, required under the ball of the foot. It has been found that at "push off" only the top layer of the foot-bed is required. This provides a more secure "push-off" and is testament to the provision of the layering, preferably being graduate; less cushioning is required, which enables a reduction in the overall size and shape of the shoe, which has a secondary benefit to stylish shoes, in particular ladies shoes, although it is important to stress that the construction of cushioning is of benefit to both male and female footwear, for young and old alike, although the benefits can be more noticeable with larger people, where the forces in walking, and in particular at faster gaits can be significant. The present invention also provides an opportunity for sales of innersoles to be based upon the weight characteristics of the purchaser as well as a nominal shoe size, since the foam density can be increased, rather than the thickness of the innersole. This is of advantage in the provision of alternatives or indeed, as a replacement, when an innersole in accordance with the invention is fitted subsequent to original manufacture.

Traditionally, foot-beds have comprised a number of composite layers running throughout the whole length of the insole board, whereby to allow for only a small wedge at the heel, or it means the look of the toe shape is compromised, thus the degree of high can be compromised. Present inventor has developed their range of insoles to allow maximum comfort whilst, with the appropriate choice of support material, maximum control in stance to enable secure footing at all times.

It is known that in many fashion industries that fashion sells; in the design of new shoes, it is believed that a layered foot-bed system in accordance with the present invention can provide an insole whereby to allow a stylish shoe to provide comfort in use; far greater than would otherwise be possible.

Claims

1. A shoe insole, the insole being operably fitted to the whole area of an inside sole portion of a shoe, from a rearmost, heel portion to support a heel of a user of the shoe to a distal portion under the toes of a wearer of the shoe; the insole comprising three layers, wherein:

a first layer comprises a heel section which extends from a rearmost portion, the heel section being sized and shaped to accommodate, in use, the weight/forces arising in use from the heel of a user of the shoe;

a second layer, extending from the heel section to an area associated, in use, with a ball of the foot, where the distal edge of the second insole layer follows, generally, an angle subtended by the phalanges; and, a third layer which overlies the first and second layers, providing the only support for the phalanges,

wherein, toward the edge of the distal edge of the second insole, the insole is chamfered and wherein the first second and third insoles are manufactured from foam in the ranges of, respectively, 40 - 50° Asker hardness; 20 - 30° Asker hardness; and 60 - 90° Asker hardness; and wherein:

the first layer defines a lift, such that, in use, the load is spread about the heel and the user's heel is raised and whereby to provide an improved spinal alignment.

2. A shoe insole according to claim 1, wherein the thicknesses of the layers are, from first to third, respectively, 3 and 7 mm; 3 and 9 mm; and 1 and 8 mm.

3. A shoe insole according to any one of claims 1 and 2, wherein the layered materials are of plastics foam and the layers have densities, from first to third, respectively, 0.13 - 0.17; 0.09 - 0.13; and 0.13 - 0.17 g/cm³.

4. A shoe insole according to any one of claims 1 to 3, wherein, toward the edge of the distal edge of the first insole, the first insole is chamfered.

5. A shoe insole according to any one of claims 1 to 3, wherein the shoe has a longitudinal axis from heel to toe and wherein the edge of the heel chamfer is substantially perpendicular to said axis.

6. A shoe insole according to any one of claims 1 to 3, wherein the shoe has a longitudinal axis from heel to toe and wherein the edge of the heel chamfer is substantially at an acute angle to said axis.

7. A shoe insole according to any one of claims 1 to 3, wherein the shoe has a longitudinal axis from heel to toe and wherein the edge of the second layer chamfer is substantially perpendicular to said axis.

8. A shoe insole according to any one of claims 1 to 3, wherein the shoe has a longitudinal axis from heel to toe and wherein the edge of the second layer chamfer is substantially at an acute angle to said axis.

9. A shoe insole according to claim 1, wherein the thicknesses of the layers are, from first to third, respectively, 5 mm; 5 mm; and 2 mm.

10. A shoe insole according to claim 1, wherein the layered materials are of plastics foam and the layers have densities, from first to third, respectively, 0.15; 0.11; and 0.15 g/cm³.

11. A shoe insole according to claim 1, wherein the layered materials are of plastics foam and the layers have hardnesses, from first to third, respectively, 45; 25; and 70 - 80° Asker.

12. A shoe insole according to claim 11, wherein the layered materials are of polyurethane foam.

13. A shoe insole according to claim 11, wherein the layered materials are of polyurethane and rubber foam.

14. A shoe insole according to claim 1, wherein, the third layer is of a thickness of between and 1 and 8 mm and comprises a laminated foam having a first upper layer with an additional layer of a harder foam which faces the second layer, the upper layer of foam being of a thickness in the range of 1 - 4mm, having a density in the range of 0.13 - 0.17.g/cm³, and a hardness in the range of 60 - 90° Asker foam and the additional layer of foam being of a thickness in the range of 1 - 4mm, having a density in the range of 0.10 - 0.14 g/cm³, and a hardness in the range of 15 - 35° Asker foam.

15. A shoe having an insole in accordance with any one or more of claims 1 - 14.