Patent Application
20150181978
The invention relates to the field of foot orthotics, shoe inserts, foot insoles, cushioning pads, and protective garments for the foot in the form of hosiery, socks, self-adhering membranes, and shoe inserts. The invention relates to foot care products that improve shoe comfort, skin protection, and provide performance enhancement. The invention also relates to gelatenous materials and high performance polymer-based textiles/materials and the processes used to fabricate such materials. The invention relates to silicone materials, including a single layered silicone material having different coefficients of friction on opposing surfaces as well as dual or multilayer silicone materials where each layer may have a thicknesses, durometer, and/or tackiness property (coefficient of friction) different than another layer(s). The invention also relates to thermoplastic membranes, polymer (polyurethane) films, extruded polyurethane extruded films, thermoplastic membrane sheets, and the processes and methods used to make such materials.
The adverse biomechanical changes that occur on a foot positioned in a high-heeled shoe have been studied and discussed. Adverse effects of high-heel shoe wear are commonly experienced by people, typically women, in the form of general pain and discomfort and more prevalent foot problems. Regular high-heeled shoe wear is a known cause to common foot problems such as, for example, skin irritation, blisters, skin stiffening, calluses, plantar forefoot pain at the forefoot, and metatarsalgia. A study by Damson et. al. (2002) reports eighty three percent (83%) of foot problems are seen in women ages 50-70 who regularly wear high-heeled shoes. It has been recommended that women not wear a heel height greater than 5 cm (about 2 inches), yet most fashionable high-heeled shoes are higher than this figure (Ebbeling et. al., 1994). Despite the pain experienced by women, the desire to be fashionable and look professional leaves the high-heeled shoe a commonplace shoe choice. It has been reported that 59% of women wear high-heeled shoes between one to eight hours a day (Gallop Org., 1986).
Several studies show that when high-heeled shoes are worn, the biomechanics of the foot changes such that the heel is raised, the toes are dorsiflexed as in the “push off” phase of the Gait cycle, the arch of the foot raises upwards, the length of the foot decreases and the foot is likely to rotate or pronate inwards (Cowley et al, 2009). The biomechanical changes that occur are known to cause the weight of the body to shift from the heel and lateral forefoot towards the central and medial forefoot, with significant increased pressure at the first and second metatarsal heads of the medial forefoot (Mandato and Nester, 1999; Speksnijder et al., 2005; Soames and Clark, 1985). It has been shown that medial forefoot pressure increases significantly the higher the heel height (Mandato and Nester, 1999; Speksnijder et al., 2005). It has also been shown that during walking, the increased pressure at the medial forefoot shifts entirely to the hallux (big toe) with a heel height higher than 3 cm (Mandato and Nester, 1999).
Most scientific studies that examine the adverse effects of the high-heeled shoe take pressure measurement readings at the external plantar surface, while the internal stress/strains of the subcutaneous plantar soft tissue (“ST”) beneath the plantar surface during high-heeled shoe wear was not well known and described until recently.
Recent studies that use sophisticated computational finite element modeling or ultrasound technology have shed light on the complex biomechanical behavior and stress/strain of the internal plantar ST and its relationship to the external pressure measurements taken at the plantar surface of the foot during high-heel shoe wear (Yu et al., 2007; Ko et al., 2009). A study by Yu et al. (2007) that uses a finite element model of the foot in a high-heeled shoe shows that while, as expected, there was an increase in von Mises stress at the first metatarsal head, there was a decrease in the strain at the plantar fascia that works to support the medial foot arch. This shows that high-heeled shoes can help alleviate the strain of the fascia/soft tissue under the medial foot arch and indicates that an arch support is less important during high-heeled shoe wear.
A study by Ko et. al. (2009) that looks at the relationship between plantar pressure and ST strain under the metatarsal heads of the forefoot when wearing different height high-heeled shoes shows that while, as expected, metatarsal pressure significantly increased and shifted to the first and second metatarsal heads with increasing heel heights, the ST strain under the metatarsal heads plateau after a heel height of 2 cm, showing that the plantar ST reaches a state of maximum compressibility at heel heights a little less than about 2 cm (1 inch). Typical heel heights range from 2-4 inches and some high-heels are 5 inches or more. The study shows that while pressure at the forefoot increases with a higher heeled shoe, the natural plantar ST padding ability has already “bottomed out” or reached its maximum cushioning ability in any high-heeled shoe over 2 cm. The study suggests that the ST reaches maximum compressibility because the ST under the forefoot is already experiencing tensile loading when the foot is positioned in a high-heeled shoe such that the heel is elevated, the toes are dorsiflexed, and the medial arch raises which, in turn, stretch out the plantar ST that runs along the longitudinal axis of the foot. The Ko et. al. study concludes that the force that the ST endures at a state of maximum compressibility cannot be properly distributed by the natural plantar ST cushioning systems of the foot and can possibly lead to internal, plantar ST strain and damage.
Another recent study by Chen et al. (2010) that uses a finite element model of the foot placed on a flat contact surface shows a large von Mises stress occurs at the medial forefoot at areas where the plantar ST contacts the geometrically irregular bony prominences of the metatarsal heads. The study also shows that the internal plantar ST displacement is highest between the fourth and fifth metatarsal heads where the ST is oriented against the oblique bone edges. The study speculates that this may lead to increased shear stresses and may explain why the ST is known to shift a small distance at the area during pressure readings. Thus, the shear displacement of the plantar ST between the fourth and fifth metatarsal heads may lead to the callused skin typically found at a women's lateral forefoot and while the reduction of pressure forces are the main concern for the comfort of the medial forefoot, the lateral forefoot at the fourth and fifth metatarsal heads could be more vulnerable to increased shear forces.
Shoe inserts are commonly known foot care products used to try to alleviate the problem of foot discomfort during shoe wear. More specifically for people that wear high-heeled shoes, shoe inserts are intended to counteract the increased medial forefoot pressure and foot pain experienced during shoe wear.
Shoe inserts are made from different shaped and sized materials designed to have bordered edges that match the general outline of the foot sole and inner shoe sole perimeter. Shoe inserts are a mass of material that is placed or adhered into the shoe body to lie flat and stationary on top of the inner sole of the shoe. Commonly known shoe inserts include basic flat full insoles, molded foot orthotics/total contact inserts (TCI), heel inserts/cushions, arch supports and ball-of-the-foot pads. Shoe inserts can also be custom made to fit an individual's foot shape in the form of a custom made foot orthotic, also known as a Custom Made Insole (CMI).
A full insole shoe insert, such as a basic insole or foot orthotic/TCI/CMI, is typically sized and shaped to cover the entire length of the inner sole and provide cushioning along the entire foot, while a heel insert/cushion, arch support, and ball-of-the footpad are of smaller shapes and sizes that target specific parts of the foot known to experience pain or discomfort during shoe wear. To provide added comfort during high-heeled shoe wear, people often use a flat shoe insert such as a ball-of-the-foot pad or basic flat insole that extends from the forefoot to the heel without protection given to the big toe (as opposed to a foot orthotic/TCI/CMI). Basic off-the-shelf flat shoe inserts have generic sizes, shapes and uniform thicknesses.
Hosiery garments are another type of product used to try to alleviate foot discomfort during shoe wear. Hosiery garments worn on the foot and leg, such as sheer pantyhose, nylons, tights, stockings, and thin socks are used during high-heeled shoe wear. Sheer/opaque stockings, tights, pantyhose, nylons, etc. are typically worn with a high-heeled pump, a strappy sandal, a shoe boot, etc., that leaves part of the foot and/or leg exposed when worn with clothing. A thin woven sock is also sometimes used for high-heeled shoe types that cover the foot body and leg such as a mid-calf or knee-high high-heel boot. The general function of these various hosiery types is to hide any physical imperfections on the legs or feet, provide a basic level of shaping and support to the leg, keep the legs and feet warm, and ease chafing between the foot and footwear. These hosiery products are typically woven in a tubular shaped form from nylon and/or spandex to have a stretchy, close fitting, form that covers the foot and leg and are thin and elegant enough to wear with high-heeled shoes. The hosiery can be worn as an undergarment but are more commonly worn as an under/outer garment that is partially exposed when wearing a skirt/dress or pants. Hosiery products come in different colors and styles and are worn as a fashion item.
Socks are yet another type of product used during shoe wear to help with comfort. A sock is woven from a variety of fiber thicknesses and materials such as cotton, wool, cashmere, acrylic, polyester, etc. into a general tubular form and is seemed at the toes. Woven socks can also have lycra/spandex added to the fiber blend to make the sock more stretchable and form fitting. Thinly woven socks are commonly worn with a closed-body high-heeled shoe type such as shoe boot/ankle boot. Thin socks are not typically used with a high-heeled shoe that exposes part of the foot body such as a basic pump or strappy sandal as it would detract from the look of the shoe, which is intended to show the natural foot form.
Athletic socks, usually intended for use with sportier shoe types, are typically made from absorbent woven cotton, wool or acrylic to absorb moisture and cushion the foot for added comfort. Specialty athletic socks can be enhanced on the insole portion of the sock with a more densely woven and/or thick fiber structure for added cushioning. Some specialty athletic socks remain thinner at the foot body and have a more densely woven, fiber structure only at the heel and forefoot providing a thicker sock with added padding at those locations. Special athletic socks can also use low-friction fibers/finishes to decrease friction and/or wick moisture away from the foot's skin. Athletic socks provide performance features not found in hosiery but are too bulky, thick, and opaque to be a viable, functional solution for use with a form-fitting high-heeled shoe.
Foot covers, liners, and toe covers can also be used during shoe wear to help with comfort and protection. Foot covers, liners, and toe covers are made to protect the foot just like any other form of hosiery, but are shaped to cover the minimal amount of the foot to provide protection only to select areas of the foot in contact with the shoe body. Foot covers come in a variety of shapes and are typically made of a known, basic hosiery material such as nylon, spandex, and/or cotton. The shape of a basic foot cover, or “peds” as they are known, is much like that of a ballet slipper; it is not as full as a sock or stocking with the cover just extending over the front of the toes to the back of the heel to cover the underside of the plantar foot. The foot cover shape is intended to remain hidden under the shoe body such that the upper foot and leg are bare and it appears that one is not wearing a hosiery item. Foot liners are appropriate for use with dressier shoes such as a high-heeled pump or during warm weather when a sock/tight or pantyhose is undesirable. Foot liners and covers are not typically woven in a circular tubular form like a sock but are rather cut out from a flat fabric woven nylon/cotton/spandex material that is seemed together to make a basic foot shaped covering.
Some hosiery items, e.g., foot covers, liners, toe covers, come enhanced with a footpad at the ball of the foot. HUE and KUSHYFOOT brand products, for example, provide nylon foot liners/covers with an added pad at the forefoot. There is also a KUSHYFOOT product with hosiery material at the sole of the foot stitched in a texturized zigzag pattern that rubs against the foot to “massage” the foot during movement.
Other cushioned hosiery products that are available for use are gel-lined socks that are commonly sold and used for therapeutic purposes and for the treatment of the diabetic foot. Gel-lined socks are made from woven textile materials having gel linings or inserts with a uniform thickness, typically covering the entire insole.
A strong need exists for an alternative new type of foot care product that alleviates the common pain, discomfort, and skin irritations that occur during high-heeled shoe wear while working with the morphological makeup and biomechanical behavior of the foot in a high-heeled shoe. There is a need for a new type of product that simultaneously replaces the need for, and offers advantages to, both the traditionally known shoe insert and the traditionally known hosiery garment. There is a strong need for a product that is of optimized, conforming, biomorphic, thin, light-weight shape, and utilizes silicone materials and/or new types of breathable membrane films/moist gels/polymers that resemble and integrate with the morphology and biomechanics of the foot and plantar ST padding to become a working “second skin” or pseudo plantar ST layer and offers a truly bare look thus eliminating the need for traditionally known shoe inserts and hosiery items; a product that enables the foot to perform closest to its natural state as an enhanced version of itself.
There is currently not one product known that will act as both a cushioned insole system and protective garment continuously and progressively, grips, flexes, and conforms directly to and with the foot body and plantar ST of the motioned foot in a high-heeled shoe at all positions and moments in time.
While there are some commercial uses of polymer-based membrane/film products existing for transparent medical wound dressings, none of those products are utilized for footwear products nor are they readily adaptable for use as footwear products. For example, JOHNSON & JOHNSON's BIOCLUSIVE product and 3M's TEGADERM product are polyurethane foil, transparent dressings. These products provide a thin flat sheet, membrane/film with an adhesive backing that is adhered onto the skin to provide a barrier from outside contaminants and to protect and help heal skin lacerations, wounds, abrasions, ulcers, or burns. The film material is known to be “semi-occlusive” to allow for moisture vapor/oxygen exchange, to be breathable, and to permit the normal functioning of the skin, yet waterproof and impermeable to water/a water droplet so that the skin is left dry when exposed to liquids, showering etc. The film is intended to keep the skin at an optimal moisture level for enhanced skin healing. The membrane film can be worn for extended periods of time, typically up to seven days. The membrane film is a thin sheet of uniform thickness that can conform to the body shape and flexes with the skin. The product comes in a variety of sizes and is individually packaged on a paper backing that is then removed when the film is applied on the skin.
Wound dressings that use a transparent membrane/polyurethane film are also available with an added absorbent pad. For example, 3M's TEGADERM Absorbent Clear Acrylic Dressing layers an acrylic polymer pad between two layers of the transparent dressing. TEGADERM Thin Hydrocolloid combines the transparent film with a hydrocolloid that contains gel-forming agents that can adhere to moist and dry skin. The hydrocolloid absorbs wound exudate liquid and forms a gel that becomes progressively more permeable to allow the dressing to continue to cope with wound exudate.
SKINTEGRITY is another brand of wound dressing with a hydrogel that is hydrophilic and primarily composed of water to create a moist environment that cushions and protects the skin.
Other known uses of polymer-based membrane films include explorations in laboratory settings by MIT Department of Aeronautics and Astronautics. The U.S. Army Natick Soldier Center made an electrospun polyethylene nanofiber mat in the shape of a facemask in 2005. This was made in a laboratory setting and shown in an exhibition called ‘Extreme textiles’ at the Copper Hewitt Museum in NYC. The mask could be used for filtration and protection as a, second, breathable skin during biochemical warfare. MIT Department of Aeronautics also experimented with a hand-held apparatus that directly sprays an electrospun clear, skin onto a human hand as a custom, form-fitting, protective glove.
Notwithstanding the foregoing, there is no known product that uses a non-woven, breathable, textile/membrane of any type of composition (polymer-based, cotton, nylon, etc.) as the singular, primary, protective garment textile/material. Some woven fabrics are treated with a film coating of nanofibers (nano-treated) but these products remain to be woven textiles. For example, NANOGLIDE makes fabrics and fibers that incorporate polytetrafluoroethylene PTFE (Patented Fiber Technology) nano particles into fibers that are then woven into a textile used to make socks for possible use for outerwear and lining applications. The fabric purportedly has enhanced performance features that control sweat/moisture, abrasion and friction. There are also other sock products that use silver nano-particles to protect against odor and bacteria. Nanofibers also have the potential to be used as a protective film when applied onto an existing woven fabric. Research for use of nanofibers as both a protective coating/layer on an existing woven fabric and to create different fibers and coatings to make three-dimensional, non-woven clothing garments was also done at the U.S. Army Natick Soldier Center by electrospinlacing.
Currently known production processes for nanofibers include a process called electrospinning. Electrospinning uses an electrical charge to draw out very fine fibers (typically on the micro or nano scale) from a liquid. It is typically used to make fibers from a polymer-base solution. Use of electrospinning nanofibers has been widely seen in laboratory settings with the use of a basic set-up that consists of a single nozzle/cone/needle that draws fibers onto a flat collector sheet, grounded molded form, or rotating cylinder collector. Production of nanofibers in a basic laboratory setting with a single nozzle/needle is slow and the materials/membranes made are often non-uniform. Laboratories that use a single nozzle/needle do experimental tests on nanofiber orientation, fiber diameter and porosity for a wide range of application in several fields. Several companies/institutions are trying to develop technologies to make nanofibers at a faster, more efficient rate with greater control and uniformity. For instance, FIBERIO is developing a “forcespinning” technology and the Harvard School of Engineering has developed a rotary jet-spinning process to make nanofibers. NANOSTATICS uses a nozzle-based technique with multiple nozzles for larger scale nanofiber production. ELMARCO, the first known manufacturer of commercial industrially scalable machines for nanofibers uses a “nanospider” technology using a needle-free electrospinning process instead of using spinning nozzles to make flat sheet nanofiber materials. The Elmarco machines currently use the “nanospider” technology to spray fine fibers back and forth, much like a printer machine onto a continuous rotating substrate sheet that collects the material over time.
The current technologies, machines, and processes for making nanofibers are unproven and significantly, none have yet to be applied to the commercial textile industry in a cost-efficient, time-effective manner. None of the existing technologies provide for a durable, light-weight, non-woven nanofiber textile for wide spread use as a stand-alone, three dimensional, nanofiber textile material and/or as a protective three dimensional coating on an existing woven fabric or fiber. None of the existing technologies are proven for use in making nanofiber materials/membranes in 3D form.
Similarly, none of the existing technologies for polymer-based membranes provide for a durable, lightweight, non-woven textile for use as a stand-alone, three-dimensional, self-supporting membrane.
The novel form, structure, and process of making the disclosed invention is such that the invention provides both a full insole, foot integrated, cushioning system and a high performance protective hosiery membrane for the foot but is not recognizable and classifiable in its form, structure, function and way of making as a traditionally known shoe insert, cushion, sock, or hosiery item. The novel invention is intended for everyday use as both a cushioned protective hosiery garment and a foot integrated, cushioning insole system to replace the commonly known hosiery items and shoe inserts currently used for high-heeled shoe wear. The invention could be a durable and reusable hosiery membrane like the conventionally known hosiery items used with the high-heeled shoe or it could be an adhesive type membrane product. The novel invention can be hand washed for continual reuse (a special cleaning formula may be formulated to clean, sterilize and even re-invigorate the product).
The present invention is a non-woven, substantially transparent, foot membrane device that helps provide comfort and support for the foot. The present invention is primarily directed towards use with high-heeled shoes, but its use is not so limited and also includes uses with other footwear including regular shoes and sneakers.
The device according to the present invention is self-supporting in that it substantially maintains its form on its own, e.g., when not worn on the foot or placed in a shoe or sneaker. The device is comprised of material that flexes, stretches and conforms to the shape of the foot, or the portion of the foot in contact with the device, when worn.
The device according to one embodiment of the present invention has a base/primary membrane that forms its primary structure with a minimal thickness to decrease its visibility when worn. Preferably, the base/primary membrane is between about 1 to 20 mils thick. More preferably, the base/primary membrane is between about 1 to 6 mils. In addition to the membrane, the device includes increased thicknesses throughout various parts of its structure to counteract the stresses experienced by the wearer of a high-heeled shoe. The parts of the invention at and around the major points of contact on the bottom of a foot at the plantar soft tissue when wearing a shoe are thicker than the other portions of the membrane which are the parts of the invention under the mid-foot plantar surface (arch), the toes (except the big toe), and the upper foot/ankle. Those thinner portions of the device are preferably comprised of a single layer of membrane material. The membrane material can be a thermoplastic polyurethane (TPU), or other materials of comparable performance and physical characteristics including a small thickness. The parts of the device under and around the forefoot/metatarsals, the big toe, and the heel, are comprised of one or more layers of membrane material and have greater total thickness than the remaining parts of the device.
Preferably, for the thicker portions of the invention, the membrane has connected to it at least one layer of gel-like material, e.g., a polymer-base gel, such as a viscoelastic polyurethane gel or silicone. The gel-like material can be positioned on top of the membrane material and/or sandwiched between a plurality of membrane layers. In one embodiment, the gel-like layer of material is positioned on top of (attached to the top) of the membrane material such that the gel-like material is in direct contact with the skin when worn.
The gel-like layer acts like a cushion helping to absorb forces and reduce stress and strain on the foot. For example, the gel-like material conforms to the protruding shapes of the metatarsal heads of the foot when weight is placed on the toes. When the gel-like layer is positioned such that it is in direct contact with skin, it is preferable to use a softer, more conformable, gel-like material. For gel-like material layers not in direct contact with the skin, the same softer gel-like material can be used or a harder and more durable gel-like material can be used.
Preferably, the gel-like material comprises a polymer-based, viscoelastic, gelatinous material. The gel-like material is soft, yet substantially non-compressible, and conformable (molds around) to the surrounding areas of the plantar surface of the foot when force is applied without reducing in thickness to the point that all of its cushioning ability is lost (bottoming out). The gel-like material according to the invention may be a moist and/or self-adhering (e.g., sticky) polymer, such as a hydrogel, or naturally sticky silicone for providing a soothing feeling to the skin when in contact. The gel-like material can also be hydrophilic or have a hydrophilic coating so it can absorb water and perspiration during wear.
The present invention may be made in the form of a sock, a ped foot liner shape, a stick-on self adhering membrane covering only certain parts of the foot, shoe insert, shoe liner, and/or sock liner for a shoe. When in sock form and/or a self-adhering form of less than an entire foot covering, the device transitions from a single, thin, layer of membrane at the bordered edges (e.g., above the ankle) and also at the thinner portions of the device having a single membrane layer only (e.g., 1-20 mil), up to anywhere between about 1 to 4.5 millimeters (mm) under the toe areas of the device beneath where the big toe will be, at the front of the device beneath where the forefoot (metatarsal heads of the foot) will be, and the back portion of the device (more specifically under a heel portion) under where the heel will be. It being understood that alternative embodiments of the invention include other thicknesses at the bordered edges and the other thinner (single membrane layer) portions of the device, such embodiments possibly worn with high-heeled shoes and/or with regular shoe wear or with sport/athletic shoes as an athletic liner during activities. It is desirable to keep the thickness of the device at the borders and at the thinnest portions of the membrane as thin as possible so as not to be visible/detected when worn, particularly where the device ends on the foot, the ankle or the leg.
For those portions of the device including gel-like material, the greatest thickness of the device is preferably between about 1 to 2 millimeters (mm) at the heel portion, between about 1.5 and 4.5 mm at the front portion under where the metatarsal heads will be when the device is worn, and between about 1.5 and 2.5 mm at the toe portion of the device where the big toe will be when the device is worn. The device is configured to have the areas with increased thicknesses at the points of most impact of the foot when the device is worn in a shoe, namely, under the toe portion at the location of the big toe, under each of the metatarsal heads (particularly the first, second and third metatarsal heads), and under the heel, with a tapering to thinner thicknesses away from those points of most impact.
The foregoing thicknesses at those portions of the device under the points of most impact on the plantar surface, which include the gel-like material, can be attained with the use of one or more layers of the membrane and/or with one or more layers of gel-like material. For example, the membrane at the heel portion of the device could be comprised of one layer of gel-like material sandwiched between two membrane layers or on top of one membrane layer. Alternatively, the membrane at the heel portion could be comprised of two or more sandwiched layers of gel-like material (each positioned between layers of membrane) combined or layered together. Even further, the membrane at the heel portion could be comprised of two or more layers of gel-like material each gel-like layer having a membrane layer beneath it.
Preferably, each gel-like layer subtly increases in thickness inward from its outer perimeter such that it is of a nominal thickness at the bordered edges and thicker in the middle region creating a gradual, sloped, tapered, transition away from the areas of the device with the added cushioning to those without added cushioning.
The membrane that makes up the primary structure of the device works in tension when the foot's own natural ST is tensioned. The membrane could be, for example, a TPU membrane. The layers of the gel-like material that are supported on a membrane layer and/or pocketed between layers of membrane work in compressive resistance to pad the foot. The membrane layer(s) that support each gel-like layer support, conform, and stretch the gel-like layer over the plantar surface and foot skin when the device is worn and the foot is placed in an elevated position in a shoe. This ensures that the gel-like layers at the “cushioned areas” with gel-like material will continuously grip onto and maintain direct contact with the plantar surface contours allowing the gel-like layers to integrate, deform, stretch, and alter, with the natural plantar ST.
The portions of the device having a single layer of membrane without any gel-like layer(s) at the middle portion of the device work in tension to support and conform in shape to the mid-foot arch. This allows the membrane to maintain direct conformity to the mid-foot even with the various changing increases in arch height that occur when the foot is placed in high-heeled shoes with different heel heights and foot bed designs. Toes, when the device is worn, will be in contact with the membrane and have a gripping ability similar to a bare foot, which will likely improve stability and give a natural/bare feeling to the foot.
The innermost surface of the membrane (the inside/interior surface) in direct contact with the skin on the foot when the device is worn has a low coefficient of friction (preferably about 0.5 or less). The innermost surface will likely be of a low coefficient of friction due to the natural material properties of the membrane material used. For example, TPU film typically has an inherently low coefficient of friction. If necessary, or desired, lubricants/additives or a PTFE coating can be used/added in a spray coating or by being impeded into the material itself to achieve the desired coefficient of friction. Alternatively, the inner surface could be coated with a viscoelastic gel having a low friction coefficient to attain this characteristic.
The entire outermost surface (outside/exterior surface), e.g., the exterior of the sock for an embodiment in sock form or the surface placed in contact with the upper surface of the insole of the footwear, has a higher coefficient of friction value, preferably 0.5 or above. Alternatively, only portions of the outermost surface, e.g., the parts of the device under the points of most impact when worn (under the heel portion, under the front portion, and/or under the toe portion), can have the higher friction surface than the remaining areas of the exterior/outer surface of the device. Even further, the entire bottom of the membrane's exterior/outer surface can be made with materials having the higher friction surface properties than the remainder of the membrane. Materials such as a high friction coating or a silicone may be used.
The novel invention offers a new alternative type of foot care product/protective garment that alleviates the adverse effects, common pain, discomfort and skin irritations experienced when wearing high-heeled shoes. The invention offers a new type of optimized foot care product that simultaneously serves the function of, replaces the need for, and eliminates the drawbacks of both the traditionally known shoe insert and the traditionally known sheer or opaque pantyhose/stocking/tight hosiery garment. The novel form, structure, and method and process of making the invention provides both a full insole cushioning system and a protective hosiery membrane for the foot, a device that is substantially not visible when worn.
The present invention redefines the form and structure of the traditionally known cushioned shoe insert from an added material object that lies inert and lifeless on the inner shoe sole base into a full insole cushioning system for the foot that integrates into the look, feel and function of the morphology and biomechanical performance of the foot body, plantar surface, and plantar ST padding. Unlike the traditionally known shoe insert, the novel cushioning system according to the invention is worn on the foot body as a clear, breathable, continuous, three-dimensional, self-supported, biomorphic foot-shaped, seamless, non-woven, surface membrane with varied contoured shapes, thicknesses, material properties throughout, that directly conforms to the foot skin and plantar surface and works as a second skin or pseudo soft-tissue padding for the foot. The invention grips, flexes, and conforms with the foot and flows and deforms alongside the natural plantar ST padding without compressing or bottoming out to maintain total contact with the entire plantar surface and complete foot body during biomechanical foot changes such that it becomes part of the force bearing surface area of the foot at all positions and moments in time to offload externally applied vertical pressure forces and provide comfort to the foot. Unlike other known shoe inserts, the “dual friction interface” surfaces provide a low friction surface at the inside surface of the membrane in contact with skin and a higher friction surface at the exterior surface in contact with the shoe (including the sole) to minimize slippage of the foot and lessen shear and frictional forces while still permitting the foot to propel properly for walking.
The invention is the first-ever cushioned hosiery-like membrane for the foot during high-heeled wear that is of a highly conforming, biomorphic-shape with contoured thicknesses that integrates with the look, feel and function of the morphological form and biomechanical performance of the foot body, plantar surface, and plantar ST, such that it is substantially undetectable to the eye. The novel invention is the first-ever protective garment for the foot during high-heeled shoe wear that is largely visually undetectable and also permits the perform/function closest to its “bare state” as an enhanced version of itself.
The invention also redefines the look, feel, form and structure of the ubiquitous sports cushioned sock into a new type of high performance, clear, protective garment for the foot suitable for high-heeled shoe wear. The invention offers the performance features similar to that of the specialty cushioned insole athletic sock in a completely refashioned and superior, clear, light-weight, ultra-thin, non-woven, seamless, optimized, form that is suitable and geared towards use with the high-heeled shoe. The invention includes an entirely clear, substantially invisible, breathable, non-woven, water-absorbent, high performance cushioned sock for the foot. The present invention offers a new type of everyday hosiery-like membrane that has performance features not found in the traditionally known sports socks or sheer nude stocking or pantyhose typically worn with high-heeled shoes and other shoes such as flats or sneakers
The present invention also includes the method and process of making the device described herein.
The invention also includes another embodiment of the device comprising a single membrane comprising a) thin portions with a minimal thickness and b) thicker areas at and around the major points of contact on the bottom of the foot at the plantar soft tissue when wearing a high-heeled shoe, that is, the parts of the invention under the big toe, metatarsal heads of the forefoot, and the heel. The increased thicknesses throughout various parts of the structure of the device work to counteract the stresses experienced by the wearer of footwear. For this embodiment made of a single membrane material, the membrane is most preferably a single durometer silicone. The silicone membrane is conformable and contourable to the wearer's foot shape. The silicone membrane is a stretchable, thermoset rubber, that resists deformity and maintains the memory and shape of that to which it is pre-formed or molded, unlike a PU which is thermoplastic. Tearing of the silicone membrane is undesirable. Accordingly, the silicone membrane is preferably equal to or greater than about 0.25 mm thick when made from a shore A 3-10 durometer. More preferably, the silicone membrane has a thickness of at least about 0.5 mm around the entire device with thicker areas at the major points of contact, e.g., the big toe portion of the device, the front portion of the device under the metatarsal heads when the device is worn, and the heel portion of the device.
For this embodiment made of a single membrane material, the coefficient of friction on the inner surface of the device (the portion in contact with the user's foot) is greater than the coefficient of friction on the outer surface of the device (the portion in contact with the insole of the footwear). This is desirable because of the intended manner of use of the device—the device is intended to first adhere onto the user's foot and then the user places his/her foot with the device on it into the footwear. Accordingly, the lower/outer surface of the device must be capable of sliding, to a degree, inside the footwear when placing the footwear on. The frictional propertied of the outer surface are still high enough, though, to help grip the foot into the shoe and prevent slippage forward or up and out of the shoe at the back heel portion. The higher friction surface at the exterior surface is, therefore, desirable because it helps secure the foot within the shoe. Thus the device, according to the invention, has a different tackiness on the inner/upper surface than on the outer/lower surface. The lower/outer surface of the device slides easier than the inner/upper surface.
For this embodiment of the invention comprising one silicone membrane layer, an increased tackiness (higher coefficient of friction) on the inner/upper surface can be achieved when the silicone membrane is comprised of a single silicone material by molding the device such that the parts of the inner/upper surface or the entire inner/upper surface of the device has a very smooth surface finish. Alternatively, an adhesive can be applied to parts of, or the entire, inner/upper surface of the device. To reduce the tackiness and achieve a lower coefficient of friction on the outer/lower surface, the silicone material of the device can be molded/made such that outer/lower surface has a more texturized, as opposed to smooth, surface finish. Still further, alternative methods to reduce the tackiness (create a lower coefficient of friction) of the outer/lower surface with or without modifying the inner/upper surface include, for example, applying a low friction coating or talc powder that lessens the tack and gives the silicone lower frictional properties.
Accordingly, for this embodiment comprising a single silicone membrane material, the inner/upper surface of the device that will be placed in contact with the user's foot includes a higher tackiness than the outer/lower surface of the device intend to be placed in contact with the footwear.
A greater tackiness (greater frictional properties) on the inner/upper surface of the device, or parts of the inner/upper surface of the device, is particularly desirable for those embodiments of the invention intended to adhere to the underside of the user's foot, e.g., pad(s) for under the big toe, the forefoot, and/or the heel. Any of the aforementioned methods and structures can be used to create the desired increased tackiness on the inner/upper surface. Preferably, and within the scope of this invention, the device includes a second layer of silicone having a lower durometer than that of the silicone membrane, on the inner/upper surface of the device with a greater “tackiness.” This second layer ensures that the membrane has maximum self-adhering properties to the foot and allows a more sturdy, higher durometer silicone (with less ‘tack’) to be used to make the base silicone membrane that supports the second silicone layer. The second silicone layer can be on the entire inner/upper surface of the silicone membrane and/or portions of the inner/upper surface of the silicone membrane can have the second silicone layer. Such a two layer, dual durometer, device is expressly included in the scope of the invention. This version of the invention, like the single layer silicone membrane, has increased tackiness (higher coefficient of friction) on the inner surface and less tack and a lower coefficient of friction on the outer/lower surface. The second silicone layer preferably comprises a very low durometer, gel-like, silicone with a coefficient of friction of about 0.75 to 1.0 or higher (such as a shore 00 20 to 40 or any silicone material typically below the shore A scale and measured on the shore 00 scale)—which is higher than the coefficient of friction for the supporting/base silicone membrane layer which is preferably equal to or less than a coefficient of friction of about 0.75 (e.g., a Shore A 3 to Shore A 10). The tack factor also serves a purpose beyond just initially positioning the device correctly. It also ensures that the device stays in place and continues to makes complete and total contact with the foot skin surface at all times to better offload forces acting on the foot.
The invention is a foot-contouring device/membrane that closely resembles the curvilinear shape of the foot's plantar surface and readily conforms to the foot (that is, it has both an exterior and interior surface that closely resembles the foot contours). The device acts as a shield to protect and maintain the natural soft-tissue form and distribution that the foot has before weight bearing and loaded conditions occur. The device allows the foot's soft-tissue to maintain its force dissipation/shock absorption properties. The device provides supplemental thickness to areas of the foot's soft-tissue padding that are known to decrease in thickness during weight bearing activities. The device, therefore, also provides a cushioning effect for comfort and support of the foot. When the device is placed on the foot within a shoe, it has been shown to have an anti-slip and suction effect that makes it such that the user's foot is less likely to slip out of and move or wobble within the shoe due to the interface of the device between the foot skin and shoe.
The surfaces of the device are pre-formed/molded to have a shape in cross and longitudinal sections that help it to closely conform to the wearer's foot. For example, the device is pre-formed/molded to have a cupping elliptical surface in cross and longitudinal section at the toe area of the device to enable it to closely conform to the toe's bottom surface. The device has a pre-formed/molded cross section at the forefoot area of the device comprising an undulating curvilinear shape consisting of two convex elliptical shapes connected in the middle by a concave elliptical shape. The device has a pre-formed/molded shape at the heel portion of the device that consists of a ‘C’ cupping shape in both cross section and longitudinal section.
The device of the invention may also be multi-layered with more than two layers of silicone comprising a first silicone membrane that is self-supporting with additional layers of material (silicone or others) added.
The invention may be held in place by a shoe or be used and/or adhered to the user's foot outside of the footwear. For the embodiment of the invention with a tacky inner surface resulting from the properties of the silicone, the ‘self-adhering’/tacky inner surface allows the device to remain in position on the user's foot without the use of traditional adhesives and without having to be attached to or used with the support of a shoe. The device is ideally placed on the foot and then the foot and device is placed in the shoe. Or the device can be placed or adhered into the shoe and then the foot can be placed in the shoe with the device. The device can also, be manufactured as part of footwear.
Alternatively, the invention may become part of a hosiery item and laminated or adhered into a sock or tight. The device can be laminated on the inner and/or outer surface of the hosiery item. A kit can be provided for the user to do this or it can be manufactured into the hosiery item. In this version of the embodiment, the inner surface of the device is better held in place by the support of the hosiery item, so the aforementioned methods used to increase the tack if the inner surfaces are not as useful.
The overall thicknesses of the device are such that not an unnatural amount of bulk is added under the wearer's foot. Rather, additional thickness is added at certain areas to compensate for the soft-tissue thickness reduction that occurs due to compressive forces acting on the toe, forefoot and heel during weight bearing activities such as walking and standing. The silicone membrane embodiment is preferably less than about 3 mm at its thickest areas to prevent taking up too much room in the shoe and causing discomfort. The device, however, could be as thick as 4 mm at certain areas, such as the portion of the device in the front under the first metatarsal head (medial side of the device in the front area) to compensate for the compressed soft-tissue reduction that occurs at that region of the foot which is showed from research to typically be as high as a range of about 4 mm.
In the most preferred embodiments, the device has the greatest thickness at the central most areas of the device at the big toe, forefoot and heel regions—the areas of the foot know to have the most contact/impact with ground forces. The greatest thickness in the big toe region of the device is preferably between about 1.5 to 2 mm in the central portion thereof; the greatest thickness in the forefoot region of the device is preferably between about 1.5 to 3 mm; and the greatest thickness in heel area of the device is preferably between about 1 to 2 mm. The portions of the silicone membrane between the areas of the device that cover the areas with the most contact/impact are about 1 mm thick. The edges of the silicone membrane preferably taper or bevel to smaller thickness. Edges are preferably about 0.5 mm thick and can be as thin as 0.25 mm, although lower durometer silicone tears more easily at that thickness.
Even though the device is stretchable and conformable, the device is ideally sized to accommodate various ranges of foot sizes, lengths and widths.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of an embodiment given below, serve to explain the principles of the present invention. Similar components of the devices are similarly numbered for simplicity.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of an embodiment given below, serve to explain the principles of the present invention. Similar components of the devices are similarly numbered for simplicity.
The device of the present invention comprises a unitary structure that is worn on the foot and/or adheres to the foot. The device includes a) a heel portion adapted to engage at least the plantar portion of the heel of a user's foot, preferably also at least some of the sides and the back (posterior) of the heel, b) a back portion adapted to engage the back of the foot behind the arch of the foot including the heel and ankle, c) a middle portion adapted to engage at least the arch of the foot and in at least some embodiments also including the sides and top of the middle portion of the foot, d) a front portion adapted to engage at least the ball aspect of the foot at the metatarsal heads (the forefoot) and in some embodiments the side and top of the foot around the metatarsals, and e) a toe portion adapted to engage at least one of the toes of the foot, namely the big toe, and in some embodiments all of the toes.
In the embodiment shown in
According to one embodiment, the device is comprised of at least one membrane around the entire device and at least one layer of gel-like material attached/connected to the at least one membrane at each of the heel portion 210, the front portion 240 at the part adapted to engage the bottom of the forefoot, and the toe portion 250 at the part adapted to engage the underside of the big toe, to create cushioned areas under parts of the foot when the device is worn.
The membrane is preferably made of a monolithic structured barrier film that is breathable and allows vapor to pass through by diffusion. The membrane is stretchable and returns to its original shape when released (e.g., taken off after wear). The membrane material prevents water and contaminants from passing through it. For example, the membrane can be made from thin polyurethane film, also known as a TPU (thermoplastic polyurethane). TPU films come in clear finishes that are either transparent or translucent, with a slightly milky whiteness, with either gloss or matte finishes. Depending on the shape of the specific embodiment of the invention, this material can be utilized in a process of making where the already made and extruded thin sheets are purchased and are thermoformed or heat stretched into a 3D shaped film membrane to make up some or all of the membrane layers of the invention.
Preferably, the gel-like material comprises a polymer-based, viscoelastic, gelatinous material. The gel-like material is soft, yet substantially non-compressible, and conformable (capable of molding around) to the surrounding areas of the plantar surface of the foot when the device is worn without reducing in thickness to the point that all of its cushioning ability is lost (bottoming out). The gel-like material according to the invention may be a moist and/or self-adhering (e.g., sticky) polymer, such as a hydrogel, or a naturally sticky silicone for providing a soothing feeling to the skin when in contact. The gel-like material can be hydrophilic or have a hydrophilic coating so it can absorb water and perspiration during wear.
The gel-like material could be a polymer-based gel, such as a viscoelastic polyurethane gel, or a silicone. The gel-like material can be on top of (attached to) the membrane material and/or sandwiched between layers of membrane layers. The gel-like layer acts like a cushion helping to absorb forces and reduce stress and strain on the foot. For example, the gel-like material conforms to the protruding shapes of the metatarsal heads of the foot when weight is placed on the forefoot/ball-of-foot while wearing the device. When the gel-like layer is positioned such that it is in direct contact with skin, a softer, more conformable, gel-like material is used as compared to when the gel-like material is a layer of material not in direct contact with the skin in which case a harder and more durable gel-like material can be used.
The gel-like material could gradate from softer and more conformable at the inner layers of the device closest to the upper surface/inside 150 where the device contacts the foot skin and harder at the outer layers closest to the exterior/lower surface/outside 160 where the device contacts the upper surface of the insole of a shoe. If only one gel-like layer is used in the device, then the gradation could occur within the one gel-like layer as opposed to between separate gel-like layers. The gradation makes the padding effect of the device more like that found in the natural plantar ST and ensures that the foot skin can sink into a soft and more conformable gel-like layer in contact with or closest to the surface of the foot skin.
The invention also includes more than one gradation change in a single gel-like layer. For example, a single gel-like layer could include five gradation changes, most hard at the outermost layer closest to the outside 160, 80% of the hardness of the outermost material at a next portion closer to the inside 150, 70% of the hardness of the outmost material next, then 60% and 50% for the successive materials in the gel-like layer. Alternatively, there could be three gradations—hard/medium/soft, or two gradation changes—hard/soft. The same gradation effect can be achieved using multiple gel-like layers each having a different hardness. For example, the device could have three gradations with five gel-like layers at the bottom 140 of the front portion 240, the outermost two layers could be the hardest, the next two gel-like layers could be of medium hardness, and last gel-like layer closest to the inside 150 could be of the soft gel gradation. For two gradation changes throughout six gel-like layers at the bottom 140 of the front portion 240, three layers could have the harder grade gel and three layers could have the softer grade gel.
In one embodiment, the device comprises at least one gel-like material layer at the bottom (underside) areas 140 of the toe portion 250 under where the device is adapted to engage the big toe, the front portion 240 under where the device is adapted to engage metatarsal heads, and the heel portion under where the device is adapted to engage the heel. A plurality of gel-like material layers could be used in embodiments of the invention to more closely configure the device to resemble the natural plantar ST structure and ensure that each individual gel-like material layer grips the foot due to the layered support of the at least one membrane layers which works in tension on the foot when the device is used/worn. In some embodiments, the number of layers of membrane and gel-like material, and/or the total thickness, is greater at the front portion 240 and the toe portion 250 than at the heel portion 210 because those areas experience more pressure during high-heel shoe wear. The number of layers of membrane and gel-like material at the heel portion 210, the front portion 240 and the toe portion 250 can vary between embodiments.
Preferably, each the heel portion 210, the front portion 240 and the toe portion 250 of the device have at least one layer of gel-like material. Alternatively, the heel portion 210 has at least two, the front portion 240 has between two and six, and the toe portion 250 has between two and four. The layers of membrane and gel-like material according to the invention function as a structure similar to the geometry of the plantar ST. Accordingly, more layers allow the device to function like real plantar ST and grips the foot.
The thicknesses of the gel-like material layers used in the device can vary as needed throughout the device to achieve the desired device configurations. For example, if two gel-like layers are used at the forefoot and the range of thickness in the inner regions of the inter-membrane gel layers are 2 to 4 mm, the thicknesses of each of the two gel layers would be 1 mm, at the area that totals a 2 mm thickness and each 2 mm at the areas that total 4 mm.
In one embodiment, at the front portion 240 of the device, the thickness for the bottom 140 is created by layering the membrane and the gel-like material to match the generally known thickness changes of the plantar ST across the width of a foot from the medial side to the lateral side when in a natural and flat position. When worn and when in a loaded state in a high-heeled shoe, the device thereby provides padding or cushioning to the foot as if it were still unloaded.
In an unloaded state, when the foot is in a prone position, there is a gradation in thickness of the plantar ST across the width of the foot. The plantar ST is thicker underneath metatarsal head 1 (M1) and thinner under metatarsal head 5 (M5). Studies have shown that the decrease in plantar ST thickness under the metatarsal heads from M1 to M5 is about 3.6 mm, give or take a standard deviation, across the foot with about 13.65+/−1.95 mm under M1 and about 10.07+/−1.19 mm under M5. The plantar ST thickness underneath the metatarsal heads (M1, M2, M3, M4 and M5) are generally know to be as follows: MT1: 13.65 mm, MT2: 12.27 mm, MT3: 11.40 mm, MT4: 10.77 mm, and MT5: 10.07 mm.
Typically, the greatest decrease in ST thickness is between M1 and M2 (about 1.5 mm) with a lesser decrease of thickness from M2 to M3 (about 0.9 mm) and then a lesser decrease from M3 to M4 (about 0.6 mm) and another decrease of thickness between M4 to M5 (about 0.7 mm). The foot device according to the present invention is configured to mimic the aforementioned thickness of the plantar ST under the metatarsal heads using one or more layers of membrane and one or more layers of gel-like material (with our without tapering) at the bottom (underside) 140 of the front portion 240 beneath the areas where the device is adapted to contact the points of main contact on the metatarsal heads. Preferably, the layering according to the invention, like the plantar ST of a healthy foot in an unloaded state, subtly decreases in thickness from M1 to M5.
The thickness of the plantar ST under the metatarsal heads changes when a foot is placed in a loaded state, particularly when in a high-heeled shoe. The plantar ST under the metatarsal heads compress non-uniformly across the width of a foot. The device of the present invention therefore includes alternative configurations for the thickness of the device, other than the aforementioned configuration with a decrease from the medial side as viewed on the foot to the lateral side, such as a configuration adapted to reflect about the same amount of the plantar ST reductions at the forefoot when maximum compressibility has been reached in a high-heeled shoe. The plantar ST reductions under maximum compression in a high-heeled shoe of 4 cm heel (1.57 inch) are MT1: 3.66 mm, MT2: 4.64 mm, MT3: 4.21 mm, MT4: 3.66 mm, and MT5: 3.26 mm. The plantar ST reduction increases from MT1 to MT2 where it is the greatest and then subtly decreases from MT2 to MT5. Between MT2 and MT5 there is a 1.38 mm ST reduction. MT1 has about 1 mm less of a plantar ST reduction than MT2. The device according to the invention is configured at the bottom 140 of the front portion 240, the part adapted to engage the foot under the metatarsals, to replace/restore the padding lost as a result of the plantar ST reductions. Accordingly, one embodiment of the invention has less thickness near the medial side of the device at the bottom 140 of the front portion 240 where the device would engage MT1 when worn than under the part of the device that would engages MT2 (the part at about the center of the width of the device, slightly closer to the medial side) which would have the greatest thickness and then tapers down in thickness therefrom towards the lateral side of the device at the bottom 140 of the front portion 240 under where the device would engage MT5 when worn.
The desired thicknesses for the device under the heel portion 210, the front portion 240, and the toe portion 250 result from a combination of the layering of membrane and gel-like material layers. The one or more gel-like layers forming the device preferably contour and taper from a nominal thickness at the bordered edges to a greater thickness at the innermost region(s). The tapering of the gel-like layers at the bordered edges to a nominally thin amount functions to help the gel-like layers transition smoothly to the at least one membrane layer.
When only one gel-like material layer is used at either the heel portion 210, the front portion 240, and the toe portion 250, then the contouring/change in thicknesses throughout the inner region(s) occurs within that one gel-like material layer. For embodiments using more than one gel-like material layer at the heel portion 210, the front portion 240, and/or the toe portion 250, the change in thickness of the innermost regions of the gel-like material layers results from contouring of the individual gel-like material layers and the layering and building up the multiple gel-like material layers. This is achieved, for example, by successively decreasing the outer/bordered area of the gel-like material layers inwards to create contoured thickness changes. For example, if three gel-like material layers are used at the front portion, the first gel-like material layer may cover the area adapted to engage under MT1 (near the medial side of the device) to MT5 (near the lateral side), while the next gel-like material layer may only cover the areas under MT1 to MT4 (more medial than M5 about halfway between the center of the device and the lateral side of the device), and the next gel-like material layer may only cover the area under MT1 to MT3 (at about the center of the width of the device) and so on. In addition to this layering method, each of the three layers of gel-like material layer could also slightly change in thickness from thinner at the area under the lateral side of the front portion 240 to thicker near the medial side of the front portion 240. This configuration, together with the successive change of shape in the bordered area of each gel-like material layer, creates a contouring and thickness variation under the metatarsals of the foot when the device is worn where the part under MT5 has the least amount of gel-like material layer thickness, MT4 has slightly more thickness than MT5, MT3 has slightly more thickness than MT4, MT2 has slightly more thickness than MT3, and MT1 has slightly more thickness than MT2.
The device according to the invention has preferred thicknesses at different parts of the device. The maximum thickness at the heel portion 210 is preferably between about 1 mm and 2 mm. Preferably, the gel-like material layer at the heel portion 210 will have less thickness, variation and contouring (less taper) than at the front portion 240 and the toe portion 250. The maximum thickness of the device at the toe portion 250 adapted to engage the big toe is between about 1.5 and 2.5 mm, preferably greater than the maximum thickness of the device at the heel portion 210 because more pressure is put on the big toe during high-heeled shoe wear. The maximum thickness at the front portion 240 is between about 1.5 and 4.5 mm depending on the specific embodiment as shown in the table in
Referring to the figures, one embodiment of the invention is shown in
The contouring shown in
For example,
As shown in
The thickness of the device at the bottom (underside) 140 of the front portion 240 around the points of most impact (at the parts adapted to engage M1, M2, M3, M4, and M5 when worn, that is, TM1, TM2, TM3, TM4, and TM5) can be a uniform thickness. Alternatively, as shown in
For example, the embodiment shown in
As used in
In
Another embodiment of the invention, a version that adheres to (stick on) the underside of the foot, intended for open shoes, and shoes that expose the majority of the foot body, such as a strappy, high-heeled sandal, or a shoe that partially exposes the foot body, such as a high-heeled pump, and in particular is worn with clothing that exposes the majority of the leg, such as a skirt, is shown in
Similar to
In
Preferably, the device includes a high-friction outer coating on the exterior 160 at the areas of the toe portion 250 (beneath where the big toe will be when worn) and/or the front portion 240 and/or the heel portion 210 that contacts the shoe sole to ensure that the foot does not slide forward in the inner shoe sole body and to contrast the lower friction inner surface 155 of the device. The high-friction outer coating could be spray applied or dip molded on as a finishing treatment or incorporated into the manufacturing process for the device if electrospinning or dip molding is used. The lower-friction inner surface of the device may be a material property of the membrane material (e.g., polyether TPU has a soft, smooth feel and is a low friction surface), or may be from special lubricants/additives embedded into the membrane material or laminated onto it. Alternatively, the inner surface 155 of the foot membrane device could be sprayed with lubricants or a low friction coating (such as PTFE) as a post-finishing treatment. Alternatively, the achievement of a low-friction inner surface may be enhanced or provided by a separate lotion or lubricant that is sold with the product and is designed to be put on the skin before the device is worn.
The low-friction inner surface of the device may also be achieved by using a gel-like layer/coating at the interior surface 155 of the heel portion 210, the front portion 240, and/or the toe portion 250 where the device makes direct contact will the skin of the foot. The inner surface 155 of the device, then, may have two different surface treatments; one of the gel-like material at the inner surface 155 of the heel portion 210, the front portion 240, and/or the toe portion 250, and the spray coating or additives/lubricant at the other parts of the inner surface 155 of the device.
For the embodiment of the invention that does not extend up the upper foot and ankle to be a sock shape but sticks to the bottom of the foot/plantar surface, a sticky, possibly removable, skin-friendly adhesive would be spray coated onto all or part of the inner surface of the device. If gel layers are placed at the inner surface 155 of the device at the innermost membrane layer, the gel of a moist/sticky polymer may be used that will have a natural stickiness, or a sticky coating may be applied to it. Even if a sticky coating and/or sticky gel is used the inner surface would still be designed to be of a lower friction than the outer surface.
The invention also includes embodiments where the membrane layer itself is made of gel-like material. For example,
In
The devices shown in
As shown in
Preferably, the thickness of the second silicone layer (gel-like layer) 704 is less than the thickness of the silicone membrane 702. Preferably, the thickness of the second silicone layer 704 is between about 6-20 mils (about 0.15 to 0.5 mm).
Alternative to the embodiment with a silicone membrane 702 covered by a silicone layer 704, the invention also includes a single silicone membrane 702 with differing friction characteristics on its two surfaces, the inner/upper surface and the outer/lower surface. The device can be molded out of a chosen, single, silicone durometer layer and achieve a contrasting tack/coefficient of friction on the surfaces by molding different surface textures. For example a low durometer, shore A 3 to shore A 10 material can be used to mold the silicone membrane with a polished surface finish for the inner/upper surface; whereas the outer/lower surface is molded with a texturized surface finish. This will provide a contrast in friction and tackiness as texturizing the surface of the silicone lowers the coefficient of friction and creates a surface that can more easily ‘slide’ over another surface; while providing a minor smooth finish to the silicone further creates a more tacky/high-coefficient of friction surface.
There are also coatings on the market that can reduce the coefficient of friction values of the outer/lower surface of the silicone membrane by about half or a range of 30-60 percent (from a 0.65 to a 0.31, for example). A talc powder can also be applied to the surface of the silicone membrane to further lower the friction values. Any of these methods may be utilized to achieve the optimal, lesser value of coefficient on the outer/lower surface of the silicone membrane. Enough slip is desired to adequately be able to slide the foot with the device on it into the footwear. At the same time, the device should not be too slippery with coefficient of friction values of 0.04-0.1, similar to those found in TPU film or a sheet of steel, which are very slippery, such that the user's foot slides to an uncomfortable degree forward in the footwear. The outer/lower surface of the silicone membrane is designed to have enough ‘bite’ and grip to keep the foot in place once the device and foot are placed into the footwear. Silicone creates this suctioning effect and helps grip the foot in the footwear to keep the device and foot in place and move more seamlessly with the shoe so that foot and shoe move as “one.”
The inner/upper surface of a single silicone membrane 702 can also include a second layer of silicone that is tacky and acts as an ‘adhesive’.
In addition the devices thickened areas at the forefoot, toe and heel resemble the way the foot's natural soft-tissue thicknesses are distributed. The invention provides added thicknesses/padding at the areas of the foot (toe, forefoot, heel) that make ground floor contact and are sustain a reduced thickness of the foot's natural soft-tissue padding due to compressive forces during weight bearing activities [such as walking and standing]. The reduced soft-tissue thickness is a phenomenon studied and known to particularly happen at the forefoot underneath the five metatarsal heads.
While the present invention has been illustrated by description of various embodiments and while those embodiments have been described in considerable detail, it is not the intention of applicant to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants' invention.
This non-provisional utility patent application is a continuation-in-part of application Ser. No. 13/630,993, filed on Sep. 28, 2012, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/626,541, filed on Sep. 28, 2011, each, which is expressly incorporated herein in its entirety by reference thereto.
| Number | Date | Country | |
|---|---|---|---|
| 61626541 | Sep 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13630993 | Sep 2012 | US |
| Child | 14657614 | US |
