Technical field of the invention

The present invention relates to shoes. More specifically, the invention relates to a high-heel shoe especially adapted for user's suffering from pain localized to the ball of the foot.

Background of the invention

Over time, the feet become wider and longer and the natural padding under the heel and forefoot thins. The forefoot is the front of the foot. Pain originating here usually involves the metatarsal bones (five long bones that extend from the front of the arch to the bones in the toe) and/or the sesamoid bones (two small bones embedded at the top of the first metatarsal bone, which connects to the big toe). Conditions defined by the localisation of the pain to the ball of the foot are e.g. metatarsalgia and sesamoiditis. The recommended footwear to alleviate the pain of metatarsalgia and sesamoiditis is low-heel and wide, box-toed shoes, often in a combination with a cushion on top of the insole to reduce the metatarsal pressure. However, women still want to use high-heel shoes. Hence, there is a need to provide a high-heel shoe solution for women suffering from pain localized to the ball of the foot.

Summary of the invention

Hence, one object of the present invention is to provide a high-heeled shoe solution for women suffering from pain localized to the ball of the foot. One aspect of the invention relates to a shoe (1) comprising:

- an outsole (10) comprising a forepart (12), a heel end (14), and a mid-portion (16) there between;

- optionally, an insole (20);

wherein the shoe (1), when in use, is adapted to raise the user's heel to a height of 2-5 cm above the user's ball of the foot;

wherein at least the part of the outsole (10) supporting the user's ball of the foot comprises a first layer (11) and a second layer (13), wherein the second layer (13) is made of a compressible material having a Shore A-scale hardness measured according to ASTM D2240-97 within the range of 40-50.

Brief description of the figures

Figure 1 shows a shoe in accordance with various embodiments of the invention.

Detailed description of the invention

All shoes have an upper, a sole, and a heel. The upper helps hold the shoe onto the foot. The upper is connected to the sole by a strip of leather, rubber, or plastic that is stitched between it and the sole, known as a welt.

The sole is the bottom of a shoe, adapted to be in contact with the ground. Soles can be made from a variety of materials. Soles can be simple, made of a single material in a single layer, or they can be complex, with multiple structures or layers and materials. When various layers are used, soles may consist of an insole, a midsole, and an outsole. The midsole and the outsole may be considered as one entity, i.e. an outsole with two layers.

The outsole is the layer in direct contact with the ground. The outsole may comprise a single piece, or may be an assembly of separate pieces and layers, often of different materials. On some shoes, the heel of the sole has a rubber plate for durability and traction, while the front is leather for style. The insole is the interior bottom of a shoe, which sits directly beneath the foot under the footbed (also known as sock liner). The purpose of insole is to attach to the lasting margin of the upper, which is wrapped around the last during the closing of the shoe during the lasting operation. The midsole is a layer in between the outsole and the insole, typically there for shock absorption. Some types of shoes, like running shoes, have additional material for shock absorption beneath the heel of the foot, where one puts the most pressure down. Some shoes may not have a midsole at all.

The heel is the bottom rear part of a shoe. Its function is to support the heel of the foot. It is often made of the same material as the outsole of the shoe, and may be an integral part of the outsole. High-heeled footwear is footwear that raises the heels significantly higher than the toes. When both the heel and the toes are raised equal amounts, as in a platform shoe, it is technically not considered to be a high-heel; however, there are also high-heeled platform shoes. High-heels are typically worn with heights varying from a kitten heel of 3-4 cm to a stiletto heel (or spike heel) of 10 cm or more. High-heeled footwear variants include kitten heels (typically 3-4 cm high) and stiletto heels (with a very narrow heel post) and wedge heels (with a wedge-shaped sole rather than a heel post).

It is to be understood that the specific shoe illustrated in the attached drawing, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific

dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. One object of the present invention is to provide a high-heeled shoe solution for humans suffering from pain localized to the ball of the foot. Generally, the pain is too grave when a human suffering from pain localized to the ball of the foot is wearing shoes adapted to raise the user's heel above the human's ball of the foot. The inventor has found that the heel may be raised to 2- 5 cm above the user's ball of the foot, provided that the outsole, at the part supporting the user's ball of the foot, comprises a layer made of a compressible material having a Shore A-scale hardness measured according to ASTM D2240-97 within the range of 40-50. This range is surprisingly narrow. If the compressible material has a Shore A-scale hardness measured according to ASTM D2240-97 below 40, the inventor has found that the user will still experience a pain localized to the ball of the foot that prevent the user from wearing the shoes. This is indeed surprising in the hardness area around 20-39 (Shore A-scale), since the material should still be able to absorb the impact energy when the user is walking. Without being bound by any particular theory, it is thought that the forefoot is forced too deep into the sole, resulting in a painful angle between the metatarsals and the proximal phalanges, i.e. in the metatarsophalangeal (MTP) joints. Prior art is mainly focused on forcing the MTP joint back into its original position by placing a pad on top of the insole, underneath the forefoot. This solution has shown to be very painful. If the compressible material has a Shore A-scale hardness measured according to ASTM D2240-97 above 50, the user will also experience a pain localized to the ball of the foot that prevent the user from wearing the shoes. This is indeed surprising in the hardness area around 51-60 (Shore A-scale), since the material is still relatively soft. Preferably, the outsole, at the part supporting the user's ball of the foot, comprises a layer made of a compressible material having a Shore A-scale hardness measured according to ASTM D2240-97 within the range of 44-48.

It is important that the outsole, at the part supporting the user's ball of the foot, comprises a layer made of a compressible material capable of returning to the uncompressed state in-between the impacts of the shoe and the surface when the user is walking, to avoid failure to absorb the impacts. This may be solved by a compressible open cell foam material. Hence, in one embodiment, the

compressible material of the second layer (13) is an open cell foam material.

In another embodiment, the compressible material of the second layer (13) is an open cell foam material or a closed cell foam material or a mixture of the two. The inventor has found that the thickness of the second layer of the outsole supporting the user's ball of the foot must be at least 5 mm when the shoe is adapted to raise the user's heel to a height within the range of 3-5 cm above the user's ball of the foot.

One aspect of the invention relates to a shoe (1) comprising:

- an outsole (10) comprising a forepart (12), a heel end (14), and a mid-portion (16) there between;

- optionally, an insole (20);

wherein the shoe (1), when in use, is adapted to raise the user's heel to a height of 2-5 cm above the user's ball of the foot;

wherein at least the part of the outsole (10) supporting the user's ball of the foot comprises a first layer (11) and a second layer (13), wherein the second layer (13) is made of a compressible material having a Shore A-scale hardness measured according to ASTM D2240-97 within the range of 40-50.

In one embodiment, the second layer of the outsole is a midsole. In one embodiment, the first layer is made of a material having a Shore A-scale hardness measured according to ASTM D2240-97 of at least 40.

The shoe, when in use, may be adapted to raise the user's heel to a height of 2-5 cm above the user's ball of the foot by a heel extending downwardly from the heel end of the outsole. The raise may also be solved by a gradually decreased thickness of the outsole from the heel end to the forepart. In one embodiment, the shoe, when in use> is adapted to raise the user's heel to a height of at 2-5 cm above the user's ball of the foot, such as 2.5-5 cm, e.g. 3-5 cm, such as 3.5-5 cm, e.g. 4-5 cm above the user's ball of the foot.

The compressible material (second layer) may be any material that can be compressed within the range of the claimed invention, such as for example a silicone, a rubber, thick or dense foam, a foam-like rubber material, or the like. Other materials may include polymers such as polyethylene blends, PVC, silicone co-polymers, block polymers or other elastic compressible materials.

In one embodiment, the compressible material is ethyl vinyl acetate (EVA). To avoid that the sides of the second layer undesirably bulges out when the shoe is in use, the edges of the second layer may be reinforced with an edging material. The edging material may be such that it is secured to the second layer by stitching. Alternatively or in addition, the edging material may be such that it is secured to the second layer by an adhesive. Particularly strong reinforcing of the second layer may be achieved with the stitching and the adhesive both being used together. The adhesive may be an acrylic adhesive. The acrylic adhesive is preferably a cross linkable acrylic based adhesive. Other adhesives may be employed.

In one embodiment, the second layer is reinforced with an edging material.

Preferably, the edging material is relatively thin, such as 0.5-5 mm, e.g. 1-5 mm, such as 2-4 mm.

In one embodiment, a part of the second layer is substituted with the edging material so that the edging material is perfectly aligned with the outer perimeter of the first layer.

The stitching of the edging material to the second layer enables the second layer to be reinforced along its periphery and this reinforcing helps to avoid the second layer to bulge out when the shoe is in use. In one embodiment, the thickness of the second layer of the outsole supporting the user's ball of the foot must be at least 5 mm, such as at least 6 mm, e.g. at least 7 mm, such as at least 8 mm, e.g. at least 9 mm, such as at least 1 cm, e.g. at least 1.5 cm, such as at least 2 cm, e.g. at least 3 cm, such as at least 4 cm, e.g. at least 5 cm.

In one embodiment, the thickness of the second layer of the outsole supporting the user's ball of the foot is within the range of 5-50 mm, such as 6 mm, e.g. within the range of 7-45 mm, such as 8 mm, e.g. within the range of 9-40 mm, such as 10 mm, e.g. within the range of 11-30 mm, such as 12 mm, e.g. within the range of 13-25 mm, such as 15 mm.

In another embodiment, the thickness of the second layer of the outsole supporting the user's ball of the foot is within the range of 5-15 mm when the shoe is adapted to raise the user's heel to a height within the range of 3-5 cm above the user's ball of the foot. Referring to figure 1, a shoe (1) is viewed from the side and includes an upper (40), a shoe sole and a heel (50). The upper (40) is provided with generally conventional or convenient construction for the type of shoe desired, such as an open upper for the sandal-type shoe as shown, with one or more straps (60) for securing the shoe to the user's foot. The upper can be provided in any style desired, such as, but not limited to, an upper for a partially or substantially closed high-heel shoe, or an upper for a high-heel boot. The upper is made from any suitable material to obtain any desired fashion or appearance of the high-heel shoe.

The shoe sole is made of an insole (20) and an outsole (10). The outsole (10) comprises a forepart (12), a heel end (14), and a mid-portion (16) there between. The forepart (12) of the outsole (10) is made of a first layer (11) and a second layer (13), where the second layer could be seen as a midsole. The first layer (11) is of generally conventional or convenient construction as desired. The first layer (11) is typically made from leather, imitation leather, or rubber material, but can be made from any other material suitable for outsoles. Preferably, the first layer (11) is made of a material having a Shore A-scale hardness measured according to ASTM D2240-97 of at least 40. When in use, the shoe is adapted to raise the user's heel to a height of 3-5 cm above the user's ball of the foot. In Figure 1, this is done by a heel (50) extending downwardly from the heel end (14) of the outsole to raise the area of the heel end of the insole (20) supporting the patients heel to a height of 3-5 cm above the area of the forepart of the insole (20) supporting the patients ball of the foot. The heel is conventionally made with a centre support shank, and then covered with a desired material, such as but not limited to leather, imitation leather, fabric, acrylic, or painted, to visibly, functionally or fashionably compliment the upper, the outsole, the midsole and the insole of the shoe. More recent shoe construction includes use of an outsole and high-heel that are integrally moulded from rubber or plastic as a single part. Still other high-heel type shoes are commonly referred to as wedge shoes, in which the heel is generally wedge- shaped when viewed from the side to raise the heel end of the outsole and insole to the desired height above the forepart of the shoe. The present invention can be used with all of these, and with other types and configurations of uppers, outsoles and heels. Designation of the specific configurations and materials of the upper, the first layer of the outsole, and the heel, are included to provide for a complete shoe.

The second layer (13) is preferably made of EVA having a Shore A-scale hardness measured according to ASTM D2240-97 within the range of 40-50, and wherein the first layer (11) is made of a material having a Shore A-scale hardness measured according to ASTM D2240-97 above 60.

In one embodiment, a concave portion is formed in the forepart (12) of the outsole (10) at a position corresponding to a first site supporting the user's big toe, ranging from the ball of the big toe to the tip of the big toe. Thereby, the weight load on the user's big toe can be reduced, and the pain in the forefoot can be further alleviated. Furthermore, the concave portion allows the big toe more space, and thereby reduces the pressure of the big toe on the other toes. It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention.