SHOE WITH SOLE PROVIDING A DYNAMIC SUPPORTING HEEL

Abstract

The invention provides a shoe with a sole providing a dynamic heel support, the shoe comprising a rubber outsole, a midsole comprising a harder elastic material, a softer elastic material, and at least one insert having a higher elastic hardness than the harder elastic material and the softer elastic material, and a higher resistance against bending, wherein the harder elastic material has elastic hardness in a range 1.3 to 3 times higher than the softer elastic material. The shoe is is distinguished in that the harder elastic material is arranged in a band inside the periphery along the sides and heel of the midsole, wherein the softer elastic material is arranged in the midsole inside the band of the harder elastic material, wherein the at least one insert is arranged within the softer elastic material, at least in the heel part of the midsole, and wherein the thickness of the softer elastic material above the insert in the heel part of the midsole is at least 0.5 times the thickness of the insert and the thickness of the softer elastic material below the insert in the heel part of the midsole is at least 1 times the thickness of the insert as measured at a centreline of the insert, excluding the thickness of any ribs on the inlay.

Claims

1. A shoe with a sole providing a dynamic heel support, the shoe comprising a rubber outsole, a midsole, comprising: a harder elastic material, a softer elastic material, and at least one insert having a higher elastic hardness than the harder elastic material and the softer elastic material, and a higher resistance against bending, wherein the harder elastic material has elastic hardness in a range 1.3 to 3 times higher than the softer elastic material, wherein the harder elastic material is arranged in a band inside the periphery along the sides and heel of the midsole, preferably the band extends in a range of 0.1 to 1 times the midsole thickness inwards from the periphery, preferably the band, in the heel part of the midsole is wider, on the medial side compared to the lateral side, wherein the softer elastic material is arranged in the midsole inside the band of the harder elastic material, wherein the at least one insert is arranged within the softer elastic material, at least in the heel part of the midsole, and wherein the thickness of the softer elastic material above the insert in the heel part of the midsole is at least 0.5 times the thickness of the insert and the thickness of the softer elastic material below the insert in the heel part of the midsole is at least 1 times the thickness of the insert as measured at a centreline of the insert, excluding the thickness of any ribs on the inlay.

2. The shoe according to claim 1, wherein the at least one insert comprises an inlay in the heel or the heel and intermediate part of the midsole, the inlay comprising at least one of the features as follows, in any combination: at least 10% thicker on the medial side than the lateral side, at least 10% stiffer on the medial side than the lateral side, twisted so as to be at higher elevation on the medial side than the lateral side, and arranged asymmetrical, to the medial side of the softer elastic material.

3. The shoe according to claim 1, wherein the at least one insert comprises a shank, the shank is embedded in the intermediate sole from the heel to the forefoot of the intermediate sole, extending over 60-95% of a last length and extending 60-95% over a last width.

4. The shoe according to claim 1, wherein the at least one insert comprises a shank, the shank is twisted in clockwise direction for a right foot midsole as seen from behind, from the heel to an intermediate part to a position in front of the naviculare bone of a user, the twisting is at an angle α2 in a range 1° to 10° from horizontal.

5. The shoe according to claim 1, wherein the at least one insert comprises a shank, the shank comprises longitudinal ribs along the shank underside, the ribs extending from the heel and intermediate part to a position in front of the naviculare bone of a user, the ribs are higher on a medial side of the shank than on a lateral side of the shank, at maximum extension the ribs extend out from the shank underside at least a distance equal to the thickness of the shank without said ribs.

6. The shoe according to claim 1, comprising an insert in the form of a shank of polymer material, preferably polyamide, preferably PA6 or PA66, preferably the shank, exclusive any ribs, is 0.5-5 mm thick and 20-45 mm wide in the heel area of the midsole.

7. The shoe according to claim 1, comprising a polyurethane as the harder elastic material, preferably polyurethane—PU—in a Shore A hardness range 40-80, more preferably Shore A about 60.

8. The shoe according to claim 1, comprising a polyurethane as the softer elastic material.

9. The shoe according to claim 1, wherein at least a part of the midsole top surface is inclined, wherein the midsole is higher on the medial side than on the lateral side in the heel and intermediate part to a position in front of the naviculare bone of a user, the inclination is at an angle α1 in a range 1° to 7° from horizontal.

10. The shoe according to claim 4, wherein α2≥α1.

11. The shoe according to claim 1, wherein: the shoe is feasible for persons suffering from diabetes, wherein the shoe comprises one or more of the features as follows, in any combination: increased horizontal dimension of the shoe, across the shoe in medial-lateral direction, by 2%, 5%, 10% or 15% or above, increased vertical dimension of the shoe between sole and upper, by 2%, 5%, 10% or 15% or above, structural modification for decreasing the contact pressure on the tissue below the toe ball of the first toe (the big toe) of a user with feet fitting the shoe size, by decreasing elastic hardness and/or lower elevation or height or thickness of the sole, in an area under the toe ball of the first toe of the user compared to the area around, preferably under the centre point of toe ball of the first toe of the user and at least 0.5 cm around said centre point, and structural modification for decreasing the contact pressure on the tissue below the heel bone of a user with feet fitting the shoe size, by decreasing elastic hardness and/or lower elevation or height or thickness of the sole, in an area under the heel bone of the user compared to the area around, preferably under the centre point of the heel bone and at least 1 cm around said point.

12. The shoe according to claim 1, wherein: at least the heel part of the sole is thicker compared to a shoe for walking, and the shoe is a running shoe.

13. The shoe according to claim 8, wherein the polyurethane is polyurethane—PU—in a Shore A hardness range 20-60.

14. The shoe according to claim 13, wherein the polyurethane is polyurethane—PU—in a Shore A hardness range of about 30.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0060] FIG. 1 is a medial-lateral cross section through the heel region of a midsole of a shoe of the invention.

[0061] FIG. 2 illustrates an insert of a midsole of a shoe of the invention, in the form of a shank.

[0062] FIG. 3 is a medial-lateral cross section through the midfoot region of a shoe of the invention.

[0063] FIG. 4 is a medial-lateral cross section through the forefoot region of a shoe of the invention, and

[0064] FIG. 5 illustrates a shoe of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0065] Reference is made to FIG. 1, illustrating a cross section medial to lateral of the heel region of a midsole 2 with rubber outsole 9 of a shoe 1 of the invention, for a right shoe midsole as seen from behind. A band 3 of the harder elastic material 4 extends inwards around the periphery of the midsole. As clearly seen, the band 3 is wider on the medial side M than on the lateral side L. The harder elastic material is also arranged on the lower part of the midsole, which lower part is attached to the rubber outsole. In the midsole, the softer elastic material 5 fills the midsole inside the band and over the lower part. Within the softer elastic material, an insert 6 in the form of an inlay or a shank can clearly be seen in cross section. If the insert is a shank, it extends further forwards in the midsole than an inlay.

[0066] It can be seen clearly, if the rubber outsole 9 is positioned on a horizontal surface, that the insert is turned clockwise, and that the top surface of the heel part of the midsole, the in substance even or flat parts thereof, excluding rims and edges, is inclined clockwise. The thickness of the softer elastic material over the medial side of the insert is 3 mm, while the thickness of the softer elastic material over the lateral side of the insert is 6 mm, in the illustrated embodiment, at the chosen location for the cross-section. The cross-section location is vertically below a center of the cuboid of a typical user. Measured at a center or centerline of the insert, the thickness of the softer elastic material over the insert is 4.5 mm. Compared to the horizontal, parallel with the underside of the midsole, it can be seen clearly that the insert is twisted clockwise more than the top surface of the midsole is inclined clockwise.

[0067] The insert is thicker on the medial side than on the lateral side, about 3 mm compared to 1.5 mm, respectively. On the underside of the insert, ribs 7 can be seen extending downwards. The ribs will for many embodiments extend far further downwards than illustrated in FIG. 1.

[0068] The insert is preferably located asymmetrical to the medial side in the softer elastic material with respect to a center of the softer elastic material, at least in the heel region of the midsole.

[0069] The specific dimensions, angles and locations are typical examples only, for a size 39 shoe. For other shoe sizes, the dimensions are adjusted linearly. For other embodiments, or for other foot problems, the twisting of the insert and the inclination of the top surface of the midsole and the dimensions and quantities of materials will be different, for example in opposite directions, or to a larger or smaller extent.

[0070] Further reference is made to FIG. 2, illustrating an insert 6, in the form of a shank 6, for embedding in a midsole in a shoe of the invention. The shank is twisted clockwise in the heel region and the midfoot region but is horizontal in the forefoot region of the shoe. This is easier seen in cross sections on FIGS. 1, 3 and 4, respectively, along the dashed lines 1-1, 3-3 and 4-4, respectively, of FIG. 2. Ribs 7 are visible only on said cross-sections. An insert of the invention, such as a shank, preferably comprises holes (not illustrated), as anchoring points for molding, and slots 11 in longitudinal direction in at least the forefoot area, for bending stiffness reduction and anchoring.

[0071] FIG. 3 illustrates a medial-lateral cross section through the midfoot region of a shoe of the invention. The shank, as well as the top surface of the midsole, are twisted clockwise, for a right shoe as seen from behind. The rubber outsole 9 has an archroller 8 integrated. On the medial side M, the archroller will touch the ground before the rest of the rubber outsole. The rubber outsole, and the integrated archroller, preferably has a hardness Shore A≥70, such as about 75, or Shore D≥30, such as about 35. The thickness of the softer elastic material 5 above the shank 6 is 0.6-2; 0.8-1.5; such as about 1 time the thickness of the shank excluding any ribs. The thickness of the softer elastic material 5 below the shank 6 is 0.6-2; 0.8-1.8; such as about 1.3 times the thickness of the shank excluding any ribs. The medial part of the shank is vertically above the medial part of the archroller. The softer and the harder elastic materials, constitute about 30-60%, or about 50% of the sole thickness. Accordingly, the elastic stiffness of the midsole in the midfoot area, particularly on the medial side, is relative higher than in the heel and forefoot areas of the sole, since more of the thickness is formed by the relative stiffer material rubber outsole/archroller and shank.

[0072] FIG. 4 illustrates a medial-lateral cross section through the forefoot region of a shoe of the invention. The thickness of the softer elastic material 5 above the shank 6 is 0.6-2; 0.7-1; such as about 0.8 times the thickness of the shank excluding any ribs. The thickness of the softer elastic material 5 below the shank 6 is 0.2-1.5; 0.3-1.2; such as about 0.5 times the thickness of the shank excluding any ribs. The sole in the forefoot is thinner, softer and with lower top surface compared to the midfoot part of the sole.

[0073] FIG. 5 illustrates an embodiment of a complete shoe 1 of the invention, with rubber outsole 9, upper 10 and (not visible) insole, seen from the lateral side. The archroller 8, with the shoe standing unloaded on a flat rigid underlayer, will not reach the underlayer on the lateral side as illustrated, but will on the medial side. By studying FIG. 3, the skilled person may recognize that this is illustrated on FIG. 3. Typically, 2-6 cm, or preferably 3-5 cm of the medial part of the archroller, dependent on shoe size, is contacted by a flat underlayer by walking. In some embodiments of the shoe of the invention, the archroller is therefore not extending over the full length from medial to lateral of the sole, under the foot arch of the user.

[0074] The shoe 1 of the invention preferably comprises an archroller 8 and a shank 6, wherein the archroller preferably is integrated in the rubber outsole or arranged between the rubber outsole and the midsole or shank. The archroller is positioned in direction medial to lateral, directly under or slightly in front of the naviculare bone of a typical user with feet fitting the shoe size. Directly under or slightly in front of, in this context means from vertically below to 4 cm in front of the naviculare bone center. Measured along the sole, from heel to front, this corresponds to 30-50% or 35-45%, more precisely 38-40% of the length from heel to front.

[0075] The archroller 8 is a conical structure with respect to cross section dimension in vertical direction with the shoe as standing on a horizontal surface. The horizontal cross section dimension is in substance identical or decreasing along the length medial to lateral of the archroller. Alternatively, the vertical and/or horizontal archroller cross-section dimension is changed stepwise.

[0076] The archroller can be of massive rubber, at least on the medial side. The medial side of a shank, if present, is arranged over the medial side of the archroller.

[0077] Preferably, the archroller is integrated into the rubber outsole. Seen from the below or from the sides, the archroller, as integrated in the rubber outsole, extends further down on the medial side than on the lateral side, as seen in FIG. 3, which includes the archroller 8 in longitudinal section. A general convex curve in the longitudinal direction of the shoe undersole surface, is crossed by 1-5 mm by the archroller on the medial side and lacking 1-5 mm on the lateral side to reach said general curve. The cross dimension of the archroller in longitudinal direction of the shoe is in substance identical or is smaller on lateral side compared to medial side. The archroller, combined with the shank, provides a dynamic, progressive support for the user, in that more pronation provides more support, in that the archroller “lifts” the shank, actually reduce the sinking down of the shank over the archroller, whilst the shank bends down around the archroller in a curve providing comfortable support for the full length of the foot arch, the plantar aponeurosis. The shank must have an appropriate bending stiffness, which is provided by choosing a shank and sole as described. Thereby, so called “naviulare drop” is reduced or prevented. Also, plantar fasciitis, heelspur and similar problems will be reduced or prevented for most users.

[0078] «Naviculare drop» is biomechanical terminology meaning that the foot arch is extended and pressed down by the weight of the body of the user. Excessive naviculare drop is reduced or prevented by the present invention. Os naviculare lift or -lifter is alternative terminology describing the effect, meaning os naviculare lift as compared to the os naviculare drop of traditional walking shoes relative to the shoe of the invention.

[0079] On the medial side, the archroller reaches the floor before the general convex undersole surface curve when setting the shoe on a floor. The archroller 8 has larger vertical dimension, is higher, on the medial side than the lateral side of the shoe, reaching a flat floor before the general convex curve of the undersole surface.

[0080] The sole of the shoe of the invention has a soft elasticity at initial compression by the foot of the user, softer than a traditional walking shoe and similar to the initial softness of a sport shoe with extensive damping. At increasing compression, the elasticity becomes progressively harder, particularly on the medial side of heel and midfoot, and more expressed in the midfoot area than the heel area. The effect, when increasing the weight on the heelbone, is that the resistance to further compression is more expressed on the medial side compared to the lateral side. As a consequence, there is a dynamic progressive resistance against too much inward rotation of the heel bone (biomechanically defined as a “heel bone valgus rotation”). The torque creates a clockwise rotation for the right foot seen from behind, effecting the vertical orientation of the heelbone as well as the vertical alignment of the achilles tendon, compared to when using a traditional walking shoe or a sport shoe. Excessive heel bone valgus rotation is thereby reduced or prevented. Likewise, when progressing the step from heel impact to midfoot stance, the foot arch is supported by progressively harder elasticity in the midfoot area, under the foot arch and particularly under the medial side thereof, earlier (at less compression) and harder elasticity, providing “os naviculare lift”. Preferably, the shoe comprises a combination of archroller and shank, whereby the archroller provides increasing force from the underlayer up on the shank at increasing compression, most on the medial side of the midfoot, whilst the shank bends and distribute the force along the foot arch.