GB2521494A

GB2521494A - Improvements in or relating to footwear

Info

Publication number: GB2521494A
Application number: GB1412185.9A
Authority: GB
Inventors: Claire Lilian Burrows
Original assignee: AIR & GRACE Ltd
Current assignee: AIR & GRACE Ltd
Priority date: 2013-12-19
Filing date: 2014-07-09
Publication date: 2015-06-24
Anticipated expiration: 2034-07-09
Also published as: EP3082488A2; GB201322629D0; DK3082488T3; WO2015092352A2; GB2521494B; PT3082488T; GB201412185D0; EP3082488B1; ES2690387T3; WO2015092352A3

Abstract

A shoe insole comprising a first layer 22 in the heel section providing lift, a second layer 24 extending from the heel section to the ball of the foot, an edge of the second layer following an angle subtended by the phalanges, and a third layer 26 overlying the first and second layers providing the only support for the phalanges. The first layer is preferably manufactured from a foam with an Asker hardness of 40-50. The second layer is formed from a foam having an Asker hardness of 20-30 and the third layer from a foam with a hardness of 60-90. The first layer is preferably chamfered. The layers may be formed from polyurethane and rubber foam. The third layer may comprise a laminated foam.

Description

Improvements in or relating to Footwear

Field of the Invention

The present invention relates to footwear for humans and, more particularly, to an 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 innersole, 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 is 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 S 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 an 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 s 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. U54972612 flexible high heel insert that is manufactured from a flat cushioning material. The insert generally has an io 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. U52005081401 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 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.

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 io 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 is 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, the first insole is chamfered. The chamfering can be provided over a length of up to 25 mm, the angle of chamfer being of the order of 1° -3°.

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 co-extensive 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 s 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 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.

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 innersole in accordance with the present invention; Figure 2b shows a side view and plan view of an innersole in accordance with the present invention, and; Figure 3 shows a completed innersole and shoe fitted with the se.

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 S into practice with variations of the specific.

Referring now to Figures 2a and 2b, which Figures show, respectively, an underside of a pair of insoles 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 io layer -a first insole layer -which extends from a rounded rearmost portion towards a gradient section 23, the gradient section tapering in thickness 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 from 0-25mm. 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 4Q0 Asker hardness, for example a polyurethane foam, such as Ortholite foam 0.15D 45° Asker, of a 5mm sheet thickness.

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 S 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.

io 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 a 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 a 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 unique 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 innersole 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. As is known, with materials such as leather and plastics used for innersoles, skiving knives trim the thickness of sheets of leather s 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 footbed, is somewhat thicker than a io 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 footbed, 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.

Claims

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 io 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 is 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 claim 1, 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 claim 1 or 2, wherein, toward the edge of the distal edge of the first insole, the first insole is chamfered.

S. 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.
6. 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.
7. 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.
8. A shoe insole according to claim 7, wherein the layered materials io are of polyurethane foam.
9. A shoe insole according to claim 7, wherein the layered materials are of polyurethane and rubber foam.
10. 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 is 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 -35° Asker foam.