GB2483298A

GB2483298A - Shoe sole with a spongy insert

Info

Publication number: GB2483298A
Application number: GB1014719.7A
Authority: GB
Inventors: Keith Alexander Derek Maunder
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-09-04
Filing date: 2010-09-04
Publication date: 2012-03-07
Also published as: GB201014719D0

Abstract

A shoe sole with an outer sole 5, an insert 1 of a soft, spongy material running nearly the whole length of the upper surface of a curved mid-sole 4. The mid-sole 4, soft spongy insert 1 and outer sole 5 have a pivot axis P, positioned at or near a mid-point of the length of the shoe sole and, in use, when a centre of pressure is exactly over the pivot axis there is formed a uniform pivot area either side of the pivot axis. The application also describes a shoe comprising an inner sole, a flexible inner sock, a soft spongy insert at the top surface of a mid-sole, and an outer sole of hard rubber.

Description

Technical Field

This invention relates to a shoe but more particularly a shoe sole that promotes comfort and good posture.

Background Art

A typical shoe has a raised heel at the back end of the sole, with no support in the middle section, which tips the wearer forward onto the balls of his/her feet. This promotes a forward lean of the body wherein the position and weight of the head is too far forward causing undue strain on the musculature and collapse of postureS Shoes for city wear have this kind of design and, as such, are not particularly healthy for the wearer. Furthermore, these soles are often too hard and generally have a flat shape that encourages a slapping down of the foot whilst walking.

There are various shoe designs that have attempted to rectify this situation. WO 01/15560 A describes a shoe with a convex-shape sole that has a pivot axis and a soft "heel sensor" built into the bottom of the heel. The shoe has a deliberate instability to encourage more active walking, however, the instability of the shoe means that it is dangerous in slippery or icy conditions and also when confronted with unexpected jolts and sudden changes in direction. As a result accidents have been known to happen. In addition the "heel sensor" in this type of shoe, made of a soft, spongy material is in an exposed position and susceptible to damage from sharp sticks and stones and sensitive to aggressive liquids containing salt, oil, manure, blood, etc. Also similar in effect to WO 01/15560 A (i.e. a shoe with a pivot axis) are the shoes of 133 5 727 335 A and EP 1 785 048 Al where a similar idea of a dual-density mid-sole is introduced. Here the mid sole is made of dual density polyester-urethane or another soft spongy material. The idea of these shoes is to cause a clearly shaped pivot axis to be defined as the centre of pressure (from the wearer's weight) moves over that part of the shoe. This causes an inbuilt instability in the shoe and more postural sway, the idea being to promote an active search by the wearer to find a balance point. The disadvantage, however, is that there is greater instability and less surface area to grip with in wet, icy or slippery conditions.

DE 20 2005 014764 131 also has a rounded toe and heel end but no pivot axis. Furthermore, the flat mid-foot area of the shoe is so large that there is little increased instability, proprioception, heightened sense of balance or significant improvement in the postural alignment. Also P1mbrose, US Patent 4,372,059 has an invention with a similar tendancy towards a large flat mid-foot area when weight bearing.

DK1184428 and DK124723B describe a shoe that tips postural alignment back toward the heel by a wedge-shaped sole that is thicker toward the front end of the foot sole. This has become known as "negative heel technology". However, too much weight is put on the heel and places an undue strain on the calf muscles.

Also Kousake et al. US Patent 5,579,591 also have a similar "negative heel technology" with similar objections to it. The present invention is a mono-density P.U. mid-sole with equal balance on either side of the pivot axis/pivot area.

Daswick, US Patent 4,241,523 has come up with an invention that has dual pivot points with the main pivot axis being at the wrong section of the foot sole.

Finally and most importantly, none of the prior inventions mentioned have a soft spongy insert glued or moulded into a recess at the top surface of the mid-sole of the shoe. This is in effect a second insole built into the main body of the shoe sole for increased shock absorbtion, health and comfort.

Disclosure of the Invention

It is an object of the present invention to address problems identified in the prior art or, at least, provide an alternative form of shoe that promotes good posture.

In one broad aspect of the present invention there is provided a shoe sole including, a curved mid-sole, a soft cushioned insert running nearly the whole length of the top of the mid-sole and an outer sole, wherein the mid-sole, cushioned layer and outer sole have a pivot axis, positioned at or near a mid-point of the length of the shoe sole and, in use, when a centre of pressure is exactly over the pivot axis there is formed a uniform pivot area either side of the pivot axis.

On top of the mid-sole there is inserted a cushioned layer of soft spongy material the "freedom sole", running nearly the whole length of the shoe sole positioned in a recess on the top of the mid sole. This can be a separate cut shape that is glued in to secure it, or the insertion of E.V.A. material into the recess during the moulding process. Preferably the mid-sole and the outer sole have a pivot axis somewhere between 40% and 50% of the length of the sole measured from the back heel. In the present most preferred form it is 44%. The rounded front toe end being anywhere between 50% to 60% of the outer sole length; and the back heel end being anywhere between 40% to 50% of the outer sole length. The outer sole is preferably made of rubber, thermoplastic urethane (TPU) or other similar material, to give a good grip.

The pivot axis is preferably positioned under the centre of the foot arch. This is calculated to be somewhere between 40% and 50% of the length of the foot sole measured forwards from the back heel. The balance at this point stimulates the natural spring of the foot arch and transmits an upward thrust through the legs, pelvis and spinal column up to the head The effect of the curved mid sole in the present invention is that as the centre of pressure (from the wearer's weight) passes over the pivot axis this actually becomes compressed to a "pivot area", not a strict point. In the present invention, when the centre of pressure is exactly over the pivot axis, a uniform "pivot area" is formed extending equidistant 3-4 cm on either side of the pivot axis.

This would not be the case in the prior art (US 5 727 335 A, WO 01/15560 Al and EP 1 785 048 Al) where the mid sole is made of dual density PU or other soft spongy material that gives an uneven compression and balance. The clear uniqueness and advantage of the present invention compared to the prior art is that, when weight bearing in the upright standing position and also when walking in the middle section of the foot roll, there is now a balanced "pivot area" extending 3-4 cm equidistant either side of the pivot axis, due to the compression of the curved PU mid sole.

This still encourages a sense of correct balance and postural alignment, being positioned exactly under and mirroring the shape of the foot arch, thus stimulating the natural spring of the foot arch, whilst at the same time giving a much better grip in wet or slippery conditions. In the present invention, the rounded nature of both the heel and toe sections encourage the wearer to balance more in the middle "pivot area" of the foot. This promotes healthy upright posture of the body and a correct heel-to-toe, heel-to-toe pattern of walking.

The other unique feature of the present invention is the insert of a soft spongy material into a recess in the top surface of the mid-sole. This is in effect a second insole built into the shoe sole and it gives clear advantages to wearers of orthotic shoe inserts who often have to remove the primary shoe insole when wearing orthotics (as retaining it affects the height of the foot within the shoe). Even after removing the first shoe insole because of the insertion of orthotics, the wearer still has the comfort and advantages of the second inbuilt insole.

Brief Description of the Drawing

Figure 1 shows a shoe and shoe sole according to the invention, and Figure 2 shows the shoe and shoe sole when weight bearing.

Mode (s) For Carrying Out The Invention In Figure 1 a shoe is shown according to the inventionwith a soft flexible material insert 1, preferably made from a soft spongy elastic material such as latex or a soft grade of P.U. This insert runs nearly the whole length of the shoe sole and follows the shape of the upper surface of the mid-sole apart from a small lip of the mid-sole PU., between 1 -15 mm wide, around the outer perimeter of the mid-sole, which remains for stronger bonding purposes. This insert is set inside a recess and glued to the mid-sole and can be from 2 -15 trim deep. Alternatively E.V.A. material can be introduced into the recess during the moulding process.

A shoe upper 2 of unique or conventional design as shown is made from leather, textile or synthetic material and is attached to the shoe sole enabling the shoe to be worn.

The soft insert 1 is positioned underneath a flexible material inner sock 3 and above the mid-sole 4. This soft, flexible material inner sock, made from textile, leather or synthetic material, allows the weight of the foot to press into the soft insert 1 when weight bearing, as shown in figure 2.

The shaped mid-sole 4 is preferably made of a shock absorbent material, such as polyester-urethane (PA).) foam with a specific gravity preferably somewhere in the range of 0.20 to 0.55 3G.

This is rounded at the front and back end of the shoe sole to encourage the wearer to walk with a heel-to-toe rolling motion to the foot. The mid-sole is shaped so that it has a pivot axis, P, anywhere in the mid-section 6, which is between 40% and 50% of the length of the shoe measured from the back heel. The shape of the mid-sole is convex as shown in Figure 1 The angle that the rounded toe end of the shoe sole makes with the horizontal axis of the shoe sole (roughly parallel with the inner sole 3), is preferably somewhere in the range of 5 to 25° (represented as the angle alpha in Figure 1). The angle that the rounded heel end of the shoe makes to the horizontal axis of the shoe sole is preferably somewhere in the range of 10 to 35° (represented as the angle beta in Figure 1).

An outer sole 5 with tread, made of rubber, thermoplastic urethane (TPU) or other similar material, for grip is also provided. The outer sole 5 is either glued to the outside of the mid-sole 4, or attached during the moulding process.

A heel section 7 is 40% to 50% of the length of the shoe sole.

A rounded toe section 8 is 50% to 60% of the length of the shoe sole.

The shoe and more particularly shoe sole, with the insert of the invention provides softness and a more stable alternative to the prior art, still with benefits to posture and exercise.

In Figure 2 the shoe and sole are depicted when weight bearing and the centre of pressure (from the wearer's weight) is positioned exactly over the pivot axis P. The shaped PU mid-sole has been compressed by the wearer's body weight and the pivot axis has now become a "pivot area" (6) in Fig. 2, extending 3-4 cm equidistant either side of the pivot axis P. This encourages a sense of correct balance and correct postural alignment, being positioned exactly under and mirroring the shape of the foot arch. This is much safer and gives better grip in wet or slippery conditions or when reacting to sudden jolts compared to the prior art WO 01/15560.

The shoe and more particularly shoe sole of the invention provides a more stable alternative to the prior art, still with benefits to posture and exercise.

It will be apparent that a shoe sole with a soft spongy insert located underneath the inner sole and a soft, flexible material inner sock is applicable to all shoe types, e.g. a dress shoe that otherwise has a flat sole and heel, and not only the posture improving shoes described herein.

Industrial Applicability

The present invention as hereinbefore described can be implemented using traditional or more modern methods and materials for production.

A

Claims

Claims: 1. A shoe sole including an outer sole, a curved mid-sole and a soft, spongy material insert, running nearly the whole length of the shoe sole and inserted into a recess on the upper surface of the mid-sole.
2. The shoe sole of claim 1 wherein the mid-sole, soft cushioned insert and outer sole have a pivot axis, positioned at or near a mid-point of the length of the shoe sole and, in use, when a centre of pressure is exactly over the pivot axis there is formed a uniform pivot area either side of the pivot axis.
3. The shoe sole of claim 1 or 2 wherein the pivot axis is positioned between 40% and 50% of the length of the shoe sole measured from the back heel and the uniform pivot area extends equidistant 3-4 cm either side of the pivot axis.
4. The shoe sole of any of the preceding claims including a rounded front toe and a rounded back heel.
5. The shoe sole of claim 4 wherein the angle that the rounded toe of the sole makes to the horizontal is 5 to 25°, and the angle that the rounded heel of the shoe sole makes to the horizontal is 10 to 35°.
6. A shoe comprising of an inner sole of leather, synthetic or textile material, a flexible inner sock of textile or synthetic material, a soft, spongy cushioned insert of latex or soft grade P.tJ. material at the upper surface of a mid-sole of medium-hard material such as polyester-urethane foam that is shock absorbent and elastic and an outer sole of hard rubber or T.P.U.
7. The shoe according to claim 6 including a shoe upper of leather, synthetic or textile material. This is glued to the shoe mid-sole by means of a soft flexible material inner sock above the soft cushioned insert.
8. A shoe sole or shoe substantially as herein described with reference to the accompanying drawings.