GB2431334A

GB2431334A - A sports shoe

Info

Publication number: GB2431334A
Application number: GB0606051A
Authority: GB
Inventors: Adri Hartveld
Original assignee: HEALUS TECHNOLOGY
Current assignee: HEALUS TECHNOLOGY
Priority date: 2005-10-18
Filing date: 2006-03-27
Publication date: 2007-04-25
Also published as: GB2431333A; GB0606051D0; GB0604058D0; GB2431333B; GB0521147D0

Abstract

A sports shoe comprises a sole with a resilient ground engaging base member 4 and an upper member 3 positioned above the base member, the upper member being more rigid than the base member. Preferably the upper member 3 has a greater rigidity beneath the heel, lateral aspect of the midfoot and fifth metatarsal and less rigid beneath the first, second and third metatarsal joints of the wearer. The upper member 3 supports the foot of the wearer and distributes the force of the impact across the resilient base member 4. Preferably the upper member may be made form carbon fibre composite or reinforced thermoplastic. The base member is preferably wedged shaped, with height of the sole is reduced from the heel to the toe of the shoe and may be made form a low density material, such as vinyl acetate, that can be compressed to 20 - 50% of its original height. Preferably the sole has a recess provided in the mid part of the base member, such that at rest the recess is not ground engaging. Preferably the sole of the shoe is heelless to prevent the heel of the shoe coming into contact with the ground during running and jumping, thereby preventing injuries caused by high heel impact forces.

Description

FOOTWEAR WITH SOLE FORCE DISTRIBUTION

This invention relates to footwear for activities such running and jumping.

Running and jumping is beneficial for one's health providing the forces on the foot do not exceed the limits the body tissues can cope with. When there is too much sideway or downwards stress on the person's joints, ligaments, muscles, tendons or bones an injury develops. The construction of the shoe soles affects the forces on the body during dynamic activities.

High impact forces during running and jumping are a major contributor to musculoskeletai injuries. The sudden increase in vertical ground reaction force (shock), when the body comes into contact with the ground, repeatedly applied to the body can lead to injuries to, or at least lead to soreness. Impact forces are reduced when the deceleration of the body mass is more gradual, i.e. over a greater time prior to hitting the ground fully. During running and jumping the shock is therefore reduced when the time between the shoe hitting the ground and the calcaneus (bee! bone) coming to a standstill is greater. In conventional running shoes this time is very brief because the material of the soles is of a medium density throughout and of limited thickness. A lower density material would not provide good shock absorption during running because the high impact forces would squash the material fully. In a fully compressed state the low density material is no longer resilient and would not be able to provide any shock absorption. In the biomechanics literature this is referred to as the "bottoming out" effect. With medium density material in conventional running shoes the thickness of the sole is limited by the weight of the sole. A thick sole would be heavy and therefore impede the running action.

Another cause of musculoskeletal injuries is excessive sideways twists because of excessive tilting when running or jumping on uneven ground, or because of slipping (the outer sole slides on the ground). With conventional shoes the sole is made of relatively firm material and stepping on a little stone would result in the shoe and the foot tilting inwards or outwards. Also, with conventional shoes, there is a relatively large area of the outer sole in contact with the ground during a step.

With a larger area there is more risk of slipping.

According to the present invention there is provided a sports shoe including a sole arrangement consisting of an upper sole, which constitutes a plate member, a midsole and an outer sole. The upper sole is made of a hard material, such as a long fibre reinforced thermoplastic and is situated above and attached to the midsole, which is made of a softer, but resilient material, such as a low density vinyl acetate. During actions such as running, when the shoe comes into contact with the ground (foot strike) the thin but hard upper sole distributes the force across the soft midsole and therefore no bottoming out takes place.

This invention provides improved shock absorption during actions such as running. A lower density material of greater thickness can be used without increasing the weight of the shoe. As in a conventional running shoe the sole is of light weight, despite the thickness of the sole, because of the lower density of the majority of the sole. As a result of the increased sole height, the calcaneus (heel bone) is further away from the ground at the very start of the foot strike. The composite materials of the sole decelerate the calcaneus over a greater distance with a less rapid increase of vertical ground reaction force as a result. Lower impact forces reduce the chance of injury. It also increases the enjoyment of running and jumping because it gives the person a bouncy feeling, instead of the feeling of a bang with every step or jump.

The sole of the shoe can be of various shapes. The top layer, the upper sole, is made of a high density material with hardness of a ShoreA value of more than 70.

The below midsole is made of lower density material with a hardness of a ShoreA value of less than 45. The sole of the shoe can be attached to the upper of the shoe in various ways. The nature of the sole materials can be varied and the thickness of the midsole can be varied, provided that the combined materials are resilient and the full sole compresses to 1% - 50% of its original height when a rapid downwards force of 600 Newton - 6000 Newton is applied. Such viscoelastic or elastic material could be made from a range of composites in a range of combinations. The outer sole could be of many various shapes and made from materials of various densities and hardness, such as soft and hard rubber.

With this invention the shoe and the foot tilt less on unevenness ground than with conventional shoes. With the softer sole construction there is increased stability because, when stepping on a stone, the stone penetrates more into the sole.

Therefore the person is at less risk of twisting injury when running in these shoes.

The mechanics of this invention with its sole force distribution system works well when the shoe is constructed with a small area of outer sole in the rear half of the shoe. This shoe shape option has an additional advantage of reduced chance of slipping. The limited surface area makes the outer sole more resistant to slipping on mud and therefore reduces injury risk.

An example of the invention and its mechanics will now be described by referring to the accompanied drawings: -figure 1 shows the rear view of a cross section of the shoe resting on a surface -figure 2 shows a cross section of the shoe when a runner applies a rapid downwards force of 2000 Newton on to the shoe sole.

In figure 1, a shoe includes an upper 2, a hard upper sole 3, a relatively soft midsole 4 and an outer sole 5, when no downwards pressure is applied to the shoe.

In figure 2, a shoe worn by a person during dynamic activities has hit the hard, but uneven ground 6 and the force from the body has resulted in a downwards movement and a tilting movement of upper sole 3. Through upper sole 3 the force is distributed across midsole 4, which results in a well distributed squashing of midsole 4. The little stone 7 on the ground 6 penetrates into the soft sole without causing increased outward tilt of the shoe.

Upper sole 3 could be the shape of a full sole or could be of various other shapes to affect force distribution and force transmission. Midsole 4 could extend across the forefoot and could be situated below the heel, but the shoe could also be heelless by shaping and placing the midsole only under the middle of the foot and under the forefoot.

Claims

1. A sports shoe, the shoe including a sole arrangement with a ground engaging resilient base member, and a plate member located above the base member and extending substantially to the rear of the shoe and to the ball of the foot, the plate member being much more rigid than the base member.

2. A shoe according to claim 1, in which the plate member includes areas of different rigidity.

3. A shoe according to claim 2, in which the plate member has a more rigid part locatable beneath the heel, lateral aspect of the midfoot, and the fifth metatarsal joint of a wearer of the shoe and a second less rigid part locatable beneath the first, second and third metatarsal joints of a wearer of the shoe.

4. A shoe according to claim 3, in which the second part is locatable beneath the more medial aspects of the sole of a wearer of the shoe.

5. A shoe according to claim 1, in which the ground engaging base member is made of a lower density material with an average hardness of a ShoreA value of less than 40 and a resilience and thickness as such that the full sole compresses to 20% - 50% of its original height when a rapid intermittent downwards force of 600 Newton - 6000 Newton is applied.

6. A shoe according to claim 1, in which the ground engaging base member is made of a lower density material with an average hardness of a ShoreA value of less than 50 and a resilience and thickness as such that the full sole compresses to 20 - 50% of its original height when a rapid intermittent downwards force of 600 Newton - 6000 Newton is applied.

7. A shoe according to any of the preceding claims, in which the base member is shaped such as to incline a wearer's foot downwardly in a forwards direction at rest.

8. A shoe according to any of the preceding claims, in which a recess is provided in the underside of a mid part of the base member, such that at rest the recess is not ground engaging.

9. A shoe according to any of the preceding claims, in which a recess is provided in the underside of the heel part of the base member, such that at rest the recess is not ground engaging.

9. A shoe according to any of the preceding claims, in which only less than 20 percent of the rear half of the shoe is engaged with the ground at rest

10. A shoe according to any of the preceding claims, in which the plate member is made of a strong carbon fibre composite.

11. A shoe according to claim 7, in which the plate member is made of a biocomposite including hemp or flax fibres.

12. A shoe according to claim 7, in which the plate member is made of reinforced thermoplastic.

13. A sports shoe substantially as hereinbefore described and with reference to the accompanying drawings, in which the ground engaging resilient base member is described by midsole 4 together with outer sole 5.

14. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.