Footwear Sole Structure with Suspended Elastomeric Web or Mesh Support
A footwear sole structure has a suspended elastomer web or mesh (1) support for a foot of a wearer of the footwear. A gap or space under the web/mesh allows it to flex down e.g. towards the outsole (3) or the ground. The web or mesh can be secured to a peripheral portion of the sole base by projections or loops (5) on the web or mesh. The web or mesh can be a one piece or multi part moulded component. The web or mesh can provide a peripheral zone around a central zone. The central body (2) can be a moulding incorporating a front strap pair (6) and rear strap pair (7) folded up into a wearing position and lugs (8), and have a higher density elastomer sole that fits up and is bonded into a matching lip in the base of the central body (2) and the elastomer web or mesh (1) fits down over the central body (2) such that the loops (5) stretch around corresponding lugs (8) on the central body (2) and the web or mesh (1) is largely held in pre-tension via the strength of the sole supports and there is still space between the web or mesh 1 and the sole for the web/mesh (1) to flex down into via weight of foot.
The present invention relates to footwear, such as shoes, boots and sandals.
BACKGROUND TO THE INVENTIONConventional footwear consists of an outer sole (outsole) for contact with the ground and an inner sole (insole) for cushioning the user's foot.
Enclosed footwear, such as shoes and boots also have an upper to enclose and position the foot.
For the sake of clarity, in this specification the term ‘footwear’ relates to outer footwear, such as shoes, boots, sandals and does not include items of fabric clothing worn on the feet, such as socks, stockings, tights and pantyhose.
Known footwear by way of conventional shoes consists of cushioned soles to provide comfort. However, no matter what the design or construction method of conventional soles, they are all based on the principle of compression cushioning. In other words, when the weight of a foot is applied to the sole, the cushioning by way of traditional foam material is compressed by the person's weight. The comfort is therefore provided by the cushioning properties of the shoe sole material under compression.
Many options have been tried to improve the cushioning properties of soles, including different types of foam and densities, air pockets, adjustable air pressure chambers, insert balls, springs etc. However, all these approaches are still based on compression of the cushioning material.
U.S. Pat. Nos. 6,601,321 and 7,555,847 by Kendall describe a shoe with a suspended, woven lattice of “high tensile strength, low ‘springiness’ fibres” and further states “In all such embodiments, the principal load bearing component of the lattice is a non-elastomeric polymer or metal based homogenous or composite fibre or yarn.”
The present invention avoids such unyielding structures, and proposes an entirely different structure having a weight bearing web formed of a flexible elastomer.
SUMMARY OF THE INVENTIONThe present invention may be utilized in or as part of a footwear structure (such as in a shoe) that features a suspended elastomer web or mesh on which, in use, the user's foot is supported.
With the aforementioned in mind, an aspect of the present invention provides a sole structure for footwear, the sole structure including a suspended elastomer web or mesh support for a foot of a wearer of the footwear.
The present invention advantageously provides a unique arrangement for footwear where the principle feature negates the need for the normal compression cushioning sole design and instead utilizes a suspended flexible elastomer mesh or web which, placed under tension by the flexing down under foot weight, provides an upward reaction force to support the weight applied through the foot of the wearer, somewhat like a flexible hammock.
It is a desirable feature of at least one form of the present invention to reverse the traditional compression cushioning of shoe soles by providing an elastomer web or mesh suspended via, at least in part, a peripheral outer sole edge such that much of the weight of the foot is absorbed by the web/mesh. Weight applied by the foot flexes the web down but in so doing stretches the web/mesh, placing its elastomer material into tension. This effectively means the foot is somewhat suspended from the ground or outsole in a flexible ‘hammock,’ suspended within the outer surround or rim of the footwear sole structure.
Air circulation is also a very significant issue as conventional shoes usually incorporate smooth areas of padding in contact with the foot, making ventilation very poor. While some shoes and sandals have been designed with small recessed grooves to improve air ventilation, by definition there still needs to be a significant cushioned area in contact without adequate air circulation.
The suspended elastomeric web/mesh footwear is able to provide superb ventilation as the open mesh design allows the majority of the foot to breathe due to the low surface area physical contact with the web/mesh.
It is most important to understand that the web/mesh elastomer not only offers comfort and ventilation but critically eases pressure on limbs such as ankles and knees. Because the mesh is a flexible elastic/elastomer material it flexes and rebounds gently to ease the impact pressure on knees, ankles etc.
The web or mesh is designed to flex down into the gap/space under the web/mesh (i.e. between the web/mesh and the outsole or, in an open soled footwear, the ground when the ground engaging part is the surround supporting the web/mesh).
During normal walking, should a large downward force be applied (such as 50 kg or landing from jumping), then the mesh can flex down until touching the sole or the ground.
It is therefore possible to also include soft foam in at least some of this space or gap. The web/mesh can therefore touch the foam if forced down far enough, which in turn can soften the pressure applied to the bottom of the sole. Importantly, although the web/mesh has ‘bottomed out’ it has still absorbed a large part of the downward force and impact in the process and can in turn rebound a percentage of this force as the web/mesh returns to a more normal position. In fact, the rebound is the most immediately noticeable characteristic of the footwear. This can effectively reduce the energy exerted by the wearer, particularly if climbing stairs etc.
In such instances of high load, because the web has absorbed a large percentage of the initial load, it means the foam can be softer than usual (on a normal shoe, the foam must take the FULL load) further accentuating the comfort of the shoe.
The footwear web or mesh/net stretches across the sole base outer rim and can be secured to the outer edges via projections, such as end knobs or loops, to fit into or over corresponding recesses or lugs respectively designed into the footwear outer.
The flexible web/mesh/net can typically be moulded flat via injection moulding and an ideal example material is flexible polyurethane thermoplastic elastomer such as used in surfboard leg-ropes or leashes. The characteristics of this material are a supreme ability to stretch and rebound.
The web/mesh elastomer may have a durometer value of 30-120 Shore A, more preferably between 80 and 95 Shore A (90 A being very typical), to provide the required elastomeric stretch characteristics with sufficient weight support. Example injection moulding grade elastomers commercially available include BASF Elastollan 1185 and BAYER Desmopan 385S®s. BASF Elastollan and BAYER Desmopan are both injection moulding grade thermoplastics.
An alternative elastomer is Erapol by Era Plastics, which is a chemical set (not injection mould grade) polymer classed as a ‘liquid isocyanate terminated pre-polymer based on PTMEG polyether polyol.’ Other elastomers, including polyurethanes, exhibiting suitable elastomeric characteristics and strength can be utilised.
Connection methods other than loops over corresponding sole base projections e.g. ‘hooks’ may be used, including examples such as knobs and slotted designs. However, an option is to mould the web and sole outer edge support in one part. This can be achieved via a single shot injection mould from the same material or an over-mould process using different materials that nevertheless bond together during the two shot over-mould process.
The web or mesh can be placed in pre-tension in the mould and once the outer sole and/or sole base is moulded around it, the pre-tension is maintained after exit from the mould.
Another option for at least one embodiment of the present invention has the upright or vertical outer edge or rim (e.g. outer sole or outsole) and the sole base moulded together as one part. Alternatively they can be over-moulded into one part if bonding is a problem. The elastomer web/mesh may be connected to the base via the loops of the elastomer, as previously described.
One or more embodiments of the present invention will hereinafter be described with reference to the accompanying drawings, in which:
The present invention will be described in relation to two embodiments, but it is to be understood that the scope of the invention is not limited to just those embodiments.
Four examples of footwear embodying the present invention are depicted in
Only the sole base needs to be bonded into a matching lip of the central body such that there is sufficient space/gap between the web and the sole base for the web to be able to flex down under weight of foot. The sole base can typically be a higher density polyurethane elastomer in the order of 65 D to ensure the sole outer does not collapse inwards under either web pre-tension or foot weight on the web. In total, this creates a complete sandal that only needs the addition of a fastener arrangement, such as hook and loop fasteners, and optional padding to complete the product.
It will be appreciated that one or more alternative embodiments of the present invention has the upright or vertical outer edge or rim (e.g. outer sole or outsole) and the sole base moulded together as one part. Alternatively they can be over-moulded into one part if bonding is a problem. The elastomer web/mesh may be connected to the base via the loops of the elastomer, as previously described.
The web/mesh can have a grid styled pattern or geometric layout, such as a hexagonal web, or more ‘organic’ or irregular arrangements/patterns, designed to specifically absorb the load of the foot.
Also, the footwear mould can incorporate as an option an upper (shoe top), such as typical leather or runner style designs or sandal designs shown as examples in
The front and rear strap pairs used as examples can be included in the single part central body shot or over-mould design process and the mould layout can be flat or with strap pairs angled at nearly 90 degrees to the web/mesh.
Alternatively, the front and rear strap pairs can be omitted and other typical conventional style uppers, such as runners etc., can be incorporated with the Web-Shoe web/mesh, outer and sole design concept.
These shoe tops/uppers can be bonded onto the central body outer top sections via conventional, known means.
A second example of the footwear structure embodying the present invention is depicted in
The ‘combs’ are generally metal lattices (the material can also be synthetic materials such as carbon or hard, reinforced injection moulded plastic) consisting of lugs for the web end loops on the top sections and teeth in the bottom sections that fit into corresponding slots in the sole/cover outer. The web is then stretched across and the end loops hooked onto the combs on each side, placing the web/mesh under pre-tension to be able to suitably absorb foot weight without flexing too far down to the sole base.
A third example embodiment of the footwear structure embodying the present invention is depicted in
A sole contains U shaped metal wire (or stiff material) pegs that incorporate horizontal sections oriented laterally across the sole. The stiffness provided stops the shoe from collapsing inward when the web/mesh/net is stretched across the pegs. The vertical sections of the U shaped pegs are designed to slot into matching holes in an H-Shaped shoe mid-section. This H-shaped mid-section incorporates the web/mesh/net throughout and is surrounded by vertical sections of the web/mesh/net elastomer that contain the peg holes.
The lower sole section (with wire pegs) fits up into the H-shaped mid-section (with holes) and the shoe upper fits on top of that. The H-shaped mid section is stretched outward to fit over the corresponding pegs in the sole, which applies pre-stretch onto the web/mesh/net to help support foot weight.
A fourth example embodiment of the footwear structure embodying the present invention is depicted in
In each embodiment of the present invention, the web/mesh is pre-tensioned. Without pre-tension, the web-mesh can too easily flex down to the sole base when the weight of a person is applied down through the foot without the web/mesh providing sufficient resistance within the short distance between the web-mesh and the ground or upper face of the outsole.
Pre-tension does not mean that the web requires unnecessary stretch; rather, it simply means that the web is taught without sagging before weight is applied. It is therefore preferred to mould the web and the vertical outer rim in one part and still incorporate sufficient pre-tension on the web with the simple addition of the sole and top.
It is possible to incorporate many different combinations of footwear design incorporating the present invention to suit the footwear market. For example, sandals, traditional shoes, runners, trainers, sneakers, thongs/flip-flops, boots etc. Design principles utilizing an embodiment of the present invention can be applied to virtually any form of outer footwear type.
In order that the invention may be more readily understood and put into practical effect, reference will now be made to the
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- (a) at the top, a typical elastomer web/mesh 1 in a diagonal grid style pattern 4 and with outer connection loops 5,
- (b) in the middle, the central body 2 being a single part moulding incorporating a front strap pair 6, rear strap pair 7, lugs 8 and inner lip 9, and
- (c) at the bottom, the higher density elastomer sole 3 featuring curved cross-brace supports 10; wherein the higher density sole 3 fits up and is bonded (or even moulded together as one part) into a matching lip 9 in the base of the central body 2 (see upwards direction arrows) and the elastomer web 1 fits down over the central body 2 such that the web loops 5 stretch around corresponding lugs 8 on the central body 2 (see downward direction arrows) such that the web/mesh 1 is largely held in pre-tension via the supports 10 and there is still space between the web/mesh 1 and the sole 3 for the web/mesh 1 to flex down into via weight of foot.
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- (a) at the top a typical elastomer web/mesh 1 in a diagonal grid pattern 4 and with outer connection loops 5,
- (b) in the middle the central body 2 being a single part moulding incorporating a front strap pair 6, rear strap pair 7 and lugs 8, and
- (c) at the bottom, but not visible, the higher density elastomer sole; wherein the higher density sole fits up and is bonded into a matching lip in the base of the central body 2 and the elastomer web/mesh 1 fits down over the central body 2 such that the web/mesh loops 5 stretch around corresponding lugs 8 on the central body 2 such that the web/mesh 1 is largely held in pre-tension via the strength of the sole supports and there is still space between the web/mesh 1 and the sole for the web/mesh 1 to flex down into via weight of foot.
Further shown is an optional thin top foam pad 120 (typically EVA or silicone foam) to cover the Web/Mesh 20 and an optional base foam pad 140 (typically EVA or silicone foam) to assist the web/mesh 20 absorb high weight loads.
It is also possible that the optional thin top foam pad 120 can be an orthotic shaped pad or even a higher density material supported by the web/mesh or web/mesh periphery.
The web/mesh can form a peripheral zone around a central zone, with the central zone being a different material from that of the web/mesh, or being the same material as the web/mesh but of a different grade of material, or different thickness or thicknesses, or having at least one different physical characteristic(s) to that of the peripheral web/mesh (such as its ‘spring’, stretch or resilience), or being a solid rather than web/mesh type material. It will be appreciated that the web/mesh can be woven or moulded elastomeric material.
Various modifications may be made in details of design and construction without departing from the scope or ambit of the present invention.
Performance characteristics of footwear, such as rebound (bounce or comfort in walking), can be measured using the following parameters:
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- a). Shock Absorption (“g”)—is a measure of deceleration, and a lower shock (g-value) generally indicates a softer sole and more comfort to the wearer. A lower g value is therefore better for comfort.
- b). Energy Return (ER)—A high ER value, while not as critical for comfort, provides “spring” in the user's step. Such ‘spring’ can reduce a user's energy expenditure and also reduce impact from shock. A high energy return value is also an indicator of resistance to ‘packing down’ of the cushion material under the foot. The higher the ER value the better for reducing energy expenditure.
Different types of footwear have different “g” & “ER” values. In general, a material with a lower “g” also has a lower “ER” as well. Independent comparative testing was conducted by the Taiwan ‘Footwear and Recreation Technology Research Institute’ on an embodiment of the present invention. The following data arose from that testing:
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Claims
1. A sole structure for footwear, the sole structure including a suspended elastomer web or mesh support for a foot of a wearer of the footwear.
2. The sole structure of claim 1, including a gap space under the web or mesh allowing the web or mesh, in use, to flex down into the gap space between the web/mesh and the outsole or, in an open soled footwear where the ground engaging part is the surround supporting the web/mesh, the ground.
3. The sole structure of claim 1, including open or closed cell foam material under the web or mesh providing impact cushioning.
4. The sole structure of claim 1, the web or mesh/net stretched across a sole base.
5. The sole structure of claim 4, wherein the web or mesh is secured to a peripheral portion of the sole base by projections on the web or mesh
6. The sole structure of claim 5, wherein the projections include knobs or loops or combinations thereof to fit into or over corresponding recesses or lugs respectively designed into the footwear peripheral portion.
7. The sole structure of claim 1, wherein the flexible web or mesh is a one piece or multi part moulded component.
8. The sole structure of claim 7, wherein the flexible web or mesh is injection moulded.
9. The sole structure of claim 7, wherein the flexible web or mesh includes polyurethane thermoplastic elastomer.
10. The sole structure of claim 7, the web or mesh being moulded with a sole peripheral portion of the footwear in one part.
11. The sole structure of claim 10, the moulding being a single shot injection mould from the same material for both the flexible web or mesh and the sole peripheral portion, or an over-mould process using differing materials that bond together during the two shot over-mould process.
12. The sole structure of claim 1, the web or mesh pre-tensioned in the mould and the outer sole and/or sole base is moulded around it to form a sole structure with the pre-tension maintained after the sole structure is removed from the mould.
13. The sole structure of claim 9, the web or mesh elastomer having a durometer value of 30-120 Shore A.
14. The sole structure of claim 13, the durometer value being between 80 and 95 Shore A.
15. The sole structure of claim 1, wherein the web or mesh forms a peripheral zone around a central zone of a different material or grade of material or a material having at least one different physical characteristic(s) to that of the peripheral web/mesh.
16. Footwear including a sole structure including a suspended elastomer web or mesh support for a foot of a wearer of the footwear.
17. Footwear according to claim 16, the footwear being a shoe, boot, trainer or running shoe or sandal.
Type: Application
Filed: Oct 30, 2013
Publication Date: Sep 10, 2015
Inventors: Graeme Scott ATTEY , Cadmus LIN (Taichung City)
Application Number: 14/438,634