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(11) | EP 2 526 803 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Footwear |
| (57) The present invention provides footwear for use in training a person to use a desired
part of the foot to engage the ground when running or walking, which footwear comprises
a sole (12) having a ground engaging part for engaging the ground during walking or
running. The ground engaging part of the sole (12) includes a base (26) and at least
one wear layer (24, 24') of different visual appearance (for example a different colour)
to material underlying it. The wear layer(s) are preferentially worn away during walking
or running in the places where the sole engages the ground to expose the visually
different underlying material, which can be used to analyse the gait of the walker
or runner. Inserts (28) can also be included in the top of the sole in places where
the user wants to train to use or train to avoid to give the user sensory feedback
as to whether he is using those places.
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Technical Field
[0001] The present invention relates to footwear, especially but not exclusively for use in running, but also for use in other sports such as walking, or a non-sport context such as recreational walking. Furthermore, the footwear of the present invention can also be used as a diagnostic tool to analyse the gait of an individual.
Background Art
[0002] Specialist running shoes are, of course, well known. They generally fall in two categories. Firstly, running shoes with a relatively thick sole, that is to say a sole thickness of in excess of 15 millimetres, which provide protection for the foot during running. Such shoes can also provide arch support, ankle support etc. Frequently such shoes have an upper that, together with the sole, tightly encloses the runner's foot.
[0003] A second alternative class of running shoe is the so-called "natural running" or "barefoot running" shoe which are very lightweight running shoes with thin soles that provide only protection against sharp objects on the running surface. The uppers can have substantial openings and/or be made of porous or semi-porous material. Such shoes are designed to provide a closer approximation to running barefoot, while still protecting the runner against sharp objects that could injure the athlete's foot.
[0004] Most runners extend their feet in such a way that the heel strikes the ground first and then the fore-foot comes into contact with the ground. Conventional running shoes, because of the thickness of their soles, tend to force the runner to adopt this mode of running. However, the advent of natural running suggests that the level of injuries suffered by runners can be reduced and/or running performance can be improved by ensuring that the fore-foot makes the first contact with the running surface. A further alternative technique is to ensure that the full foot makes contact with the running surface simultaneously, i.e. the runner lands simultaneously on the heel and fore-foot. Such alternative running techniques have been pioneered by natural running courses (Pose Method, Chi Running or Alexander Technique).
[0005] It is an object of the present invention to provide footwear that will provide visual feedback of the part of the foot that first strikes the ground/running surface and may also provides sensory feedback and therefore can be used in learning new running techniques such as those discussed above. Although the above discussion has concentrated on running, similar considerations apply also to the sport of walking, especially long distance competitive walking.
Disclosure of Invention
[0007] Broadly speaking, the present invention provides footwear that includes a relatively thin wear layer of material on the bottom of the footwear sole. Several wear layers can be provided so that, when the outermost wear layer has been worn away, the next layer shows through. If the wear layers have different visual appearances, for example different colours, a user can see precisely where the runner is landing his foot and which part of the sole is coming into contact with the running surface during the running stride. This is because it is the part of the sole that first strikes the running surface that is most worn. Thus, if a person wishes to change their running style so as to become a fore-foot striker (i.e. ensure that their fore-foot is the first part of the foot to strike the ground), then analysis of the wear patterns on the bottom of the soles will provide feedback as to whether he has succeeded.
[0008] So that the feedback function is not used up when the first wear layer is eroded, the shoe can have several wear layers, each of different visual appearance from its neighbours. Preferably, at least two wear layers, and optionally three, four or even five layers may be provided; in theory, there is no upper limit to the number of wear layers that can be incorporated into the footwear of the present invention, although an overly large number of such layers increases the thickness of the sole, which is not desired for barefoot running shoes.
[0009] So that a person can get relatively quick feedback, the bottom wear layer is preferably made of relatively soft material. The various wear layers may have a Shore hardness (measured on the Shore A hardness scale) of between 70 and 100, for example 80 to 90. The outermost layer preferably has a lower hardness than successive layers. The thickness of the wear layers may be up to 1 millimetre each, for example 0.3 to 0.9 millimetres.
[0010] A further aspect of the present invention is the provision of a substantial number of projections on the underside of the sole and it is the ends of the projections that contact the ground and the wear layers should then be provided at least at the end of such projections. The use of projections provides sensory feedback to the user of where he has planted his foot in a running stride since the projections engaging the ground cause a pressure on the part of the foot overlying the projections concerned, which can be felt by the user. These projections may be hollow to provide greater deformation during the running stride; although this will reduce the level of feedback, the runner can still feel the projections pressing into his foot as he runs, and, because the projections are hollow, this need not be uncomfortable.
[0011] Further sensory feedback can be provided by an insert providing a raised region on the top of the sole, i.e. the part of the footwear sole that supports the foot. Such inserts are preferably removable and may be made of a material that is harder than the underlying sole so that the user can also feel the insert as he runs. These inserts could stand proud from the rest of the sole by a distance of 1 to 5 mm. An insert can be placed in one of many locations on the foot-supporting part of the sole and one or more inserts can be used at the same time. The location of an insert can be chosen so that the person feels it when he lands on a part of his foot that he wants to avoid landing on or when he lands on a part of his foot that he wants to land on, thereby obtaining feedback when he has placed his foot in a manner that he wants to adopt. Either way, he can obtain feedback on his running technique and correct it where necessary as he goes along. Instead of providing an individual insert as discussed above, a similar effect, i.e. one or more raised regions standing proud of the part of the footwear that supports the foot, could be achieved using a removable insole into which movable inserts could be included or that containing a one or more raised regions in fixed locations that are suitable for teaching specific styles of running.
[0012] The insert exaggerates the wear of the wear layers immediately underneath and so can amplify the feedback from the wear layers discussed above.
[0013] In accordance with one embodiment, the inserts may be a flat disk (or other shape) that underlies the foot. In accordance with another embodiment, the flat disk (or other shape) could have a prong on its underneath surface that engages in the hollow interion of the projections, thereby fixing the inserts in place in a convenient manner.
[0014] In order to reduce the weight of the footwear, it is preferably made from a light, but durable foam material such as foamed polyurethane or foamed EVA (ethylene vinyl acetate copolymer). Such materials can last a substantial length of time before the footwear is worn out and needs replacing.
[0015] In one embodiment, the footwear is made as a single piece, with the sole being connected to a heel portion and an "upper" portion, i.e. a portion that will form the upper of the footwear; the footwear will also include fastenings to secure the heel portion and the upper portion around the user's foot. Such fastenings may be burr (also known as "hook-and-loop") fastenings, such as Velcro (Velcro is a Trademark). Alternatively, a lace may be provided that extends under the sole and wraps around the upper to ensure that the fore-foot is secured within the footwear. The same lace can surround the user's ankle to keep the heel portion in place. If laces are provided, loops, straps or guides can be used to guide the laces and keep them in a fixed position during running. In an embodiment, fasteners may be used to secure the heel portion that can be separately released from the rest of the shoe to allow the user to withdraw his foot from the rear of the shoe without undoing all the other fasteners. An example of such an arrangement is described below.
Brief Description of the Drawings
[0016] An example of a shoe in accordance with the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Figure 1 is a side view of a shoe in accordance with the present invention showing the shoe as it is worn;
Figure 2 is a perspective view of the shoe of Figure 1 taken from above and one side;
Figure 3 is a perspective view of the shoe of Figure 1 before it is folded around a user's foot;
Figure 4 is a perspective view of the underneath of the unfolded shoe of Figure 3;
Figure 5 is a side view of the unfolded shoe that is also depicted in Figures 3 and 4;
Figure 6 is a sectional view through the unfolded shoe depicted in Figures 3 to 5;
Figure 7(a) to (c) and (d) to (e) are, respectively, cross sections through a projection on the sole of the shoe depicted in Figure 6 and bottom views of the same projection, showing various states of wear of the projection; and
Figure 8 is a sectional view of the projections of Figure 7 and also showing the inclusion of an insert.
Best Mode for Carrying Out the Invention
[0017] Referring initially to Figures 1 and 2, which depict the shoe in a folded state, as it is worn. The shoe 10 includes a sole 12, an upper portion 14 and a heel portion 16. The shoe is maintained on the user's foot by means of a lace 19, which will be described in greater detail later.
[0018] The shoe depicted in Figures 1 and 2 has been folded up; Figure 3 to 5 show the same shoe in an unfolded or folded out state, that is to say before it is folded around the user's foot.
[0019] As can be seen, the sole 12, the upper portion 14 and the heel portion 16 are integrally formed as a single piece. The soles 12 of the shoe are provided with an array of projections 18 that are hollow and the hollow interior cavity 22 can be seen in Figures 3 and 6 to 8. The upper portion 14 and the heel portion 16 include through-holes 20 to provide ventilation to the foot during wearing.
[0020] The ends of the projections 18 include two wear layers 24, 24' which are applied on top of a base layer 26. The wear layers 24, 24' and the base layer 26 all have different colours so that, when the wear layers are eroded (see Figure 7) the individual layers can be seen. The wear will primarily occur at the ends of the projections 18. The outer wear layer 24 is shown intact in Figures 7 (a) and (d) while Figures 7 (b) and (e) show the projections 18 after the outer layer 24 has been worn away to reveal the underlying second wear layer 24'. Finally, Figures7(c) and (f) show the situation in which the two wear layers 24 and 24' have been worn away from the bottom of the projection 18 to reveal the base layer 26. Naturally, the wear layers 24, 24' will be preferentially worn away in the areas where the sole most engages the ground, particularly where there is relative movement between the sole and the ground which particularly occurs in the areas where the foot first strikes the ground. Therefore, if a runner starts off as a "heel striker", i.e. a runner that first engages the grounds in any stride with his heel, and wants to convert to a "fore-foot striker", i.e. a runner that first engages the grounds in any stride with his fore-foot, then he can easily detect from the wear patterns whether he is continuing to engage the ground first with his heel or with his fore-foot. As such, the shoe of the present invention provides a useful analytical tool to help a runner (or a running advisor) discern the mode or technique of running. In addition, if the runner rolls his ankle so that he is mainly supported on the outside (or inside) of his foot, rather than running uniformly on the bottom of his foot, then this will be discernable from the wear patterns of the wear layers 24, 24'. Away from the field of sport, the same technique can be used to analyse the gait of a person who strikes the ground in an uneven way, which can cause ankle problems or problems of posture.
[0021] As can be seen in Figure 6, the wear layers 24, 24' extend over the whole of the folded out shoe but it is possible, instead, only to provide the wear layers at the bottom of the projections.
[0022] The wear layers 24, 24' should be relatively thin (up to 1 millimetre thick) and may be made with relatively soft material (with a Shore hardness of 70 —100, e.g. 80 to 90 on the A scale) so that it does not take a prolonged period to see the results of the wear. Preferably, the outer wear layer 24 is made with softer material than the second wear layer 24' so that the results are quickly discernable from wear layer 24 and wear layer 24' is made of harder material that is not so rapidly worn away, thereby prolonging the life of the shoe. Likewise, the hardness of the base later 26 is preferably greater than that of the wear layer 24', again to prevent the shoe from being worn away too quickly, that is to say the use of an increased hardness about prolonged the lifetime of the shoe.
[0023] The projections 18 can be felt by the user as he runs and this will provide useful feedback as to his running style. However, it is also possible to include an insert 28 that stands proud of the upper surface of the sole 12, as shown in Figure 6. The insert 28 has a disk-shaped head 30 and a prong 32 that can engage in the hollow interior cavity 22 inside one of the projections 18. Side teeth 34 (see Figure 8) can engage the side walls of the hollow cavity 22 to prevent the insert 28 being pulled out readily. However, it is of course, possible to move the insert 28 from one cavity 22 to another. The inserts 28 provide increased feedback to the user and can be placed either at a position where the user does not wish to engage the ground (thereby providing feedback that his mode of running is not what he wants) or at a place where he does want to engage the ground (thereby providing the feedback that his mode of running is correct). More than one insert 28 can be included on the sole, although only one is shown in Figure 6. The inserts may be made of flexible material, such as foam. They may have a hardness greater than that of the base material 26 so that the sensory feedback to the user is increased. The presence of an insert 28 above a projection 18 increases the wear of the layers 24, 24' thereby allowing the user particular information relating to the engagement of the ground of the part below the insert. The shape of the head 30 can be different from the disk shape shown in Figures 6 and 8 although sharp corners and edges should be avoided to prevent injury to a user's foot.
[0024] The overall thickness of the material making up the sole 12 may be up to 5 millimetres so that the overall height of the sole between the bottom of a projection 18 and the top surface of the sole may be less than 15 millimetres. The thickness at the heel portion 16 and the upper portion 14 may be less than that at the sole 12 because there are no projections in the upper and heeled portions 14, 16; however, it is also possible to make the upper portion and the heel portion thinner than the sole since they do not have to withstand the same abrasion forces.
[0025] In order to make the opened out shoe shown in Figures 3 to 6 into a wearable shoe, the upper portion 14can be bent around hinge section 35 about the axis (shown by arrows 36) to bend the upper portion 14 over the top of the user's foot. Likewise, the heel portion 16 can be bent around a further hinge section 37 (about an axis indicated by arrows 38) to enclose the user's ankle.
[0026] Many different forms of fastenings can be used to keep the upper and heeled portions 14, 16 engaged around the user's foot and one example is shown in Figures 1 and 2. A single lace 18 for each shoe is provided. The centre of the lace 18.1 is passed between two rows of projections 18 and across the top of the upper portion 14 (see 19.2 on Figure 2) before passing under the sole again between two rows of projections 18. As it passes underneath the sole, the lace may be enclosed in a protective tube 21. The lace crosses over again on top of the upper portion 14 (see 19.3 of Figure 2) before passing round the heel portion twice. The ends of the lace are then pulled tight and clamped together by a clamp 42 which keeps the laces tight. While passing round the heel portion 16, the laces are held by loops 44 that may be threaded through slots 45 (see Figure 5) in the upper portion 14 and in the heel portion 16. The loops can be kept closed for example by a burr (also known as a "hook-and-loop") fastener such as Velcro. One loop 46 deserves special mention since it is connected to a corresponding loop on the other side of the foot, which is not visible by a band 47 that extends under the sole of the shoe. The band may have holes that fit onto the projections 18, which helps to keep the band 47 in place.
[0027] In order to take the shoe off, the clamp 42 is released and this slackens the laces that pass around the heel portion 16. This means that the heel portion 16 can be pulled down (a loop 50 may be attached to the heel portion to make this easier). The foot can then be slipped horizontally backwards out of the shoe without the need to retie the laces which pass over the upper portion 14. In order to put the shoe on, the above procedure can be reversed.
[0028] As mentioned above, the shoe may be made from expanded foam material, such as EVA or polyurethane. The shoe need not be made of foam, however, but a foam is preferred because it is lighter and provides a greater cushion during running or walking. EVA is a thermoplastic, which allows the shoe to be recycled after it has worn out, for example by grinding it into particles, which can be reused.
[0029] The shoe can be manufactured by moulding the base material 26, i.e. the whole of the shoe body apart from the wear layers 24, 24'; the moulded material may contain a blowing agent that is subsequently activated, e.g. by heat, to form the foam. The wear layers 24, 24' may be sprayed on or applied by dipping or indeed any other suitable process such as a process known in toy manufacture involving laying down one or more layers in the mold and then overmolding ( in an injection molding process) with the foam material. Generally, both spraying and dipping will require the wear layer material to be heated and, in the case of spraying, this could therefore take place in an oven.
[0030] The hardness of the base layer 26 and of the wear layers 24 and 24' can be controlled in a manner well known in the art to provide the required degree of hardness. As stated above, the outer wear layer 24 preferably has a lower hardness (for example 70 to 80 Shore hardness on the A scale) than the inner wear layer 24' (which can have a hardness of, for example, 80 to 90 Shore hardness on the A scale) and the inner wear layer 24' is, in turn, softer than the base layer 26 which can have a hardness, for example, of 90 to 100 on the Shore A scale. It will be appreciated that the relative hardnesses within the range of 70 to 100 can be different from those mentioned above.
[0031] The shoe has been described in terms of a one-piece construction principal for natural running/barefoot running. However, the sole may be used in a conventional running shoe with a separate upper to which the sole is secured.
[0032] The above description also concentrates on running but is applicable to other sports and pastimes such as walking. The present invention also find an application in diagnosing people with a poor gait that may need correcting since the poor gait will manifest itself in the user preferentially using a limited part of the foot and this will cause the wear layers 24, 24' to be worn away in the part of the shoe sole underlying this preferred foot part.
1. Footwear for use in training a person to use a desired part of the foot to engage
the ground when running or walking, which footwear comprises a sole (12) having:
a foot supporting part that is configured to lie below the person's foot and
a ground engaging part for engaging the ground during walking or running,
wherein the ground engaging part of the sole (12) includes a base (26) and at least one layer (24, 24') of different visual appearance (for example a different colour) to material underlying it, the said at least one layer being a wear layer that is configured to be preferentially worn away during walking or running in the places where the sole engages the ground to expose the visually different underlying material.
2. Footwear as claimed in claim 1, which also includes at least one insert (28) that
is attachable to the foot supporting part of the sole (12) in one of a plurality of
locations, the insert being configured such that the person can feel the insert with
his foot when he lands on the part of his foot above the insert, thereby providing
sensory feedback when he is landing on the part of the foot above the insert.
3. Footwear as claimed in claim 1 or claim 2, wherein the foot supporting layer of the
sole (12) includes a series of indents (22) and wherein the or each insert (28) includes
a portion that can be inserted into one of the indents to hold the insert in a fixed
position relative to the indent.
4. Footwear as claimed in any proceeding claim, wherein the ground engaging part of the
sole (12) comprises a plurality of projections (18) that engage the ground, wherein
the at least one layer (24, 24') is provided at least on the ground engaging ends
of said projections.
5. Footwear as claimed in claim 4, wherein the projections (18) are hollow.
6. Footwear as claimed in both claims 3 and 5, wherein the indents (22) are formed by
the hollow interior of the projections (18).
7. Footwear as claimed in any one of claims 2 to 6, wherein the inserts are flexible
and have a greater hardness than the foot supporting part of the sole.
8. Footwear as claimed in any one of claims 2 to 7, wherein the inserts are such that
they stand proud of the top of the foot supporting part of the sole by a distance
of at least 1mm for example 1.5 to 5 mm.
9. Footwear as claimed in any one preceding claim, wherein the, or the outermost, wear
layer is made of a softer material than material underlying it so that it wears away
faster than the underlying material on engagement with the ground during running or
walking.
10. Footwear as claimed in any one preceding claim, which includes at least two wear layers
(24,24') each wear layer being of a different visual appearance to the material underlying
it.
11. Footwear as claimed in any one preceding claim, wherein the or each wear layer (24,24')
has a Shore hardness of 70 to 100, optionally 80 to 90, measured on the Shore A hardness
scale.
12. Footwear as claimed in any one preceding claim, wherein the or each wear layer (24,24')
has a thickness of less than 1.5 mm, for example 0.3 to 0.9 mm.
13. Footwear as claimed in any one preceding claim, wherein the sole is made of foam material.
14. Footwear as claimed in any one preceding claim, wherein the sole is integrally formed
with a heel portion (16) that can be bent to cover the person's heel and an upper
portion (14) that can be bent to cover the top of the person's foot, and wherein the
footwear includes at least one fastening (19) for securing the heel portion and the
upper portion around the person's foot, for example a lace that can wrap around the
front of the sole (12) and around the upper portion (14) of the footwear to secure
the upper portion around the person's foot and that can wrap around the person's ankle
to secure the heel portion (16) to the person's foot.
15. Footwear as claimed in claim 14, wherein the heel portion can be selectively released
by the at least one fastening to allow the person to remove the footwear from his
foot or to insert the footwear onto his foot.