Patent Description:
Modern footwear is designed to suit a wide variety of applications. Footwear is evaluated based on how the footwear looks (form), accomplishes the intended application (function), and accommodates the wearer's foot (fit). Footwear designers balance these parameters to meet a wearer's expectations. This balance is important to achieve overall comfort while mitigating the occurrence of foot pain and/or the development of foot disorders. For example, a running shoe might be designed to dampen ground impact while providing cushioning during ground contact and returning energy to propel the runner forward. The designer can adjust the aesthetics of the shoe to appeal to the intended wearer while also providing structural elements to meet length, width, and arch type requirements. Therefore, the running shoe can be appealing, function as intended, and properly fit the wearer's foot. Unfortunately, some footwear does not (or cannot) have a proper balance of form, function, and fit. In fact, the intended purpose for some footwear, such as high-fashion footwear, is aesthetic appeal, which results in a large overlap between form and function that can compromise the ability of the footwear to comfortably fit the wearer's foot and help reduce the occurrence of pain and/or disability.

High heeled shoes, for example, have heel-to-toe drops of between <NUM> to <NUM> (two to five inches) with a hard backbone to support the shoe structure. This configuration intentionally shifts the wearer's foot into a more rigid arch structure while transferring the loads observed during walking from the heel and mid-foot to the medial forefoot. This manifests as reduced arch flexibility and increased ball of foot pressure that can cause the wearer acute and chronic pain after extended wear. Ballet flat style shoes are another example of high fashion footwear that overlaps form and function while sacrificing fit and comfort. Like high heeled shoes, ballet flats are typically designed to have a snug fit but are also built to be flexible and move with the wearer's foot. This sock-like form and function compromises the shoes ability to provide any arch support or sufficient cushioning. This compromise can manifest as acute and chronic pain after extended wear.

Traditionally, aftermarket insoles and orthotics are designed to extend the function of certain shoes to provide the wearer with a better fit. A design engineer can use a combination of compliant and rigid materials to provide cushioning to the entire foot and support the heel and arch during gait. These components help stabilize foot motion while distributing the load across a larger area of the foot during gait. This can help improve the comfort of the footwear as well as reduce the incidence of acute and chronic foot pain. Unfortunately, high fashion footwear, such as high heels and ballet flats, often does not accommodate many conventional aftermarket insoles and orthotics well. Arch support is especially difficult to implement in these shoe styles because they are rigid or semi-rigid structures that do not have the needed flexibility to match the varied contours of all heights of high heels or flex and move with a ballet flat during walking. As a consequence, arch support is either left out or created using a build-up of compliant material that adds bulk and, in many instances, further reduces the overall fit and comfort of the footwear. A customizable component insole system is known from <CIT>.

According to some embodiments, an insole for footwear includes a flexible yet supportive arch support that can be incorporated into the insole for improving the comfort and fit of a broad range of footwear. The flexible arch support includes a plurality of leaf-spring like ribs that are located at different heights. A first set of the ribs is configured to form a base of the arch portion of the insole and a second set of the ribs is raised relative to the first set. Gaps between ribs increase the flexibility of the arch in the direction perpendicular to the longitudinal direction of the ribs so that the arch support can contour more easily to fit and move with different types of footwear. The ribs may extend from a frame that forms the perimeter of the arch support.

According to the present invention there is provided an insole for insertion into footwear as defined in claim <NUM>. Additional embodiments are defined in the dependent claims.

Described herein are embodiments of flexible arch supports and insoles having flexible arch supports. According to various embodiments, the flexible arch support is configured with alternating supportive leaf spring ribs separated by gaps in material. The ribs may be braced by an outer support brim or frame. A first set of ribs extends downward forming at least a portion of the bottom of the arch support for contacting a wearer's footwear. A second set of ribs form at least a portion of the plantar surface of the arch support for contacting a wearer's foot or the base of an insole.

The alternating bottom and plantar contact leaf spring ribs are configured to support the arch structure of the foot by functioning as independent leaf springs that provide tailored support to the wearer's arch under different loading conditions. The gaps between the leaf springs ribs are configured to allow the flexible arch support to flex in the direction perpendicular to the orientation of the semi-elliptical leaf springs.

The flexible arch support may be one unitary construction that may be manufactured from any of a wide variety of materials, using, for example, injection molding or 3D printing techniques. The flexible arch support may be tailored for different purposes by modifying one or both of the leaf spring rib geometry and material properties. For example, the semi-elliptical leaf spring height and orientation may be configured to be larger on the medial side or to be more uniform across the medial-lateral direction depending on the desired function, shoe shape, and/or wearer's anatomy. Moreover, the alternating semi-elliptical leaf spring structures may be tailored to provide a range of support by changing the material properties from compliant to stiff and visa-versa.

A conventional arch shell is designed to have a contoured but uniformly rigid shape that acts as a supportive spring under the arch during the stance phase of gait. These conventional arch supports are commonly used to effectively support the arch in a variety of footwear. However, the conventional arch supports are resistant to bending forces and do not provide the needed flexibility to be effectively incorporated into high fashion footwear, such as high heel shoes and ballet flats. Conversely, the flexible arch support described herein, according to various embodiments, is configured to reduce the material stress when subjected to bending loads relative to a conventional arch shell design, allowing for greater displacement or flexion in the direction perpendicular to the leaf spring ribs while still providing support for the arch structure of the foot during gait.

In the following description of the disclosure and embodiments, reference is made to the accompanying drawings in which are shown, by way of illustration, specific embodiments that may be practiced.

In addition, it is also to be understood that the singular forms "a," "an," and "the" used in the following description are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is also to be understood that the term "and/or"," as used herein, refers to and encompasses any and all possible combinations of one or more of the associated listed items. It is further to be understood that the terms "includes, "including," "comprises," and/or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, components, and/or units, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, units, and/or groups thereof.

As used herein, insole broadly refers to any insert into footwear for supporting the underside of a wearer's foot and includes orthotics, aftermarket inserts, and inserts that are built into footwear by the footwear manufacturer.

<FIG> illustrate medial side, top, and front views, respectively, of a flexible arch support <NUM> having an array of leaf spring ribs, according to some embodiments. The flexible arch support <NUM> may be built into an insole or may be used by itself. The flexible arch support <NUM> includes a plantar side <NUM> that faces in the direction of a wearer's foot, a bottom side <NUM> that faces and may contact the plantar side of a wearer's footwear, a medial side <NUM> that underlies the medial side of a wearer's foot, and a lateral side <NUM> that underlies the lateral side of a wearer's foot. Ribs <NUM> extend from the medial side <NUM> to the lateral side <NUM> for supporting a wearer's arch while providing flexibility to conform to different footwear. The ribs <NUM> are spaced apart by gaps <NUM> so that the ribs <NUM> form independent leaf springs that provide increasing levels of resistance as they are loaded, providing support to a wearer's arch. The gaps <NUM> provide flexibility to the arch support <NUM> in the direction perpendicular to the longitudinal extent of the ribs <NUM>, so that the arch support <NUM> may bend more easily than, for example, a monolithic arch shell.

In some embodiments, the flexible arch support <NUM> is configured for placement directly beneath the arch of a typical wearer's arch. For example, the flexible arch support <NUM> may be configured to extend longitudinally from at least the talus-navicular joint of a typical target wearer's foot to the medial cuneiform-first metatarsal joint and laterally under at least the medial cuneiform bone to support the arch cavity when the flexible arch support is in use.

In the illustrated embodiment, the ribs <NUM> are configured into two sets of ribs in which ribs from the first set alternate with ribs from the second set. A first set of ribs <NUM> extend along the plantar side <NUM> of the arch support <NUM>. A second set of ribs <NUM> extend lower than the first set of ribs and collectively form at least a portion of the base side <NUM> of the arch support <NUM>. A frame <NUM> forms a perimeter of the arch support <NUM> and the ends of each rib extend from the frame <NUM>. In the illustrated embodiment, the frame <NUM> extends fully around the perimeter of the arch support <NUM>, but in other embodiments, the frame may form only a portion of the perimeter of the arch support, such as first and second sides where the ribs <NUM> end. During use, as the wearer applies pressure to the arch support, the first set of ribs <NUM> and the second set of ribs <NUM> move toward each other, acting as opposing leaf springs, providing increased resistance as more pressure is applied.

The frame <NUM> and the upper surfaces <NUM> of the first set of ribs <NUM> may be configured to form a plantar side <NUM> that contours according to a typical target wearer's foot. For example, with respect to the medial side view of <FIG>, the plantar side <NUM> may curve upward from the front to the middle of the arch support <NUM> and then curve back downward to the rear of the arch support <NUM>. With respect to the front view of <FIG>, at least some of the ribs of the first set of ribs <NUM> may dip downward in the middle so that the plantar side has a convex shape medially to laterally. The portion of the frame <NUM> on the medial side <NUM> and the portions of the ribs <NUM> extending therefrom may be higher than the portion of the frame <NUM> on the lateral side <NUM>, thus tracking the arch of a typical wearer's foot.

The second set of ribs <NUM> may be configured to form a bottom side <NUM> that contours according to a typical target wearer's footwear. For example, from front to back, the bottom surfaces <NUM> of the second set of ribs <NUM> in the illustrated embodiment collectively form a somewhat convex surface for footwear that includes a slight upward curve in the arch area. In other embodiments, the bottom surfaces <NUM> form a flat surface and may be configured to form any suitable surface shape. Medially to laterally, the second set of ribs <NUM> may be configured to provide a flat central portion that rises on the medial and lateral sides (see, for example, <FIG>) or may be configured to provide a lowest point that is off-center, such as to the medial or lateral side (see, for example, <FIG>).

As stated above, the second set of ribs <NUM> dip downward relative to the first set of ribs <NUM>. Thus, the upper surfaces <NUM> of the second set of ribs <NUM> are below the portion of the plantar side <NUM> of the arch support <NUM> formed by the first set of ribs <NUM>. With the arch support <NUM> placed in an article of footwear (such as by itself or incorporated into an insole), the first set of ribs <NUM> and at least a portion of the upper surface of the frame <NUM> receive the initial pressure applied from above (either directly by a user's foot or by a portion of an insole into which the arch support <NUM> is incorporated, as discussed further below), while the second set of ribs <NUM> receive the initial pressure from the footwear. As additional pressure is applied to the arch support, such as when a wearer stands on the foot, the two sets of ribs are compressed toward one another.

As illustrated in <FIG>, gaps <NUM> are provided between adjacent ribs. The gaps <NUM> provide flexibility in the direction perpendicular to the longitudinal direction of the ribs <NUM>. This may enable the arch support <NUM> to conform to, for example, high heels that have large heel to toe drops and/or to move along with highly flexible footwear, such as ballet flats.

The ribs <NUM> may be configured in any suitable shape in profile and cross-section. For example, in profile, one or more ribs may form a semi-ellipse, and may have a flat central portion with curved end portions, or may have a maximum dip that is offset from the center. Ribs of the same arch support may have the same shape or may have different shapes. Ribs of the first set of ribs <NUM> may have a different shape than ribs of the second set of ribs <NUM>. For example, ribs of the first set of ribs may have a flat central section while ribs of the second set of ribs may have a maximum dip toward a medial side of the arch support to provide more support at the highest portion of a wearer's foot.

Ribs may have any suitable cross-sectional shape. For example, in some embodiments, ribs may have a rectangular cross section, with flat upper and lower surfaces and straight sides, while in other embodiments, ribs may have one side that is flat and another side that is curved. Ribs of the first set of ribs <NUM> may have a different cross-sectional shape than ribs of the second set of ribs <NUM>. For example, ribs of the first set of ribs <NUM> may have an upper surface <NUM> that is contoured for a wearer's foot and lower surfaces <NUM> that are flat while ribs of the second set of ribs <NUM> may have a contoured bottom surface <NUM> and a flat upper surface <NUM>.

In the illustrated embodiment, the two sets of ribs alternate such that a rib from the first set of ribs is adjacent to a rib from the second set of ribs. In other embodiments, a different pattern may be used, such as a repeating pattern of two first set ribs followed by one second set rib or a repeating pattern of two first set ribs followed by two second set ribs, or any other suitable pattern. Further, while the ribs <NUM> in the illustrated embodiment extend side-to-side medially to laterally, ribs according to various other embodiments may extend directly front-to-back or at any angle between directly side-to-side and directly front-to-back.

According to some embodiments, a flexible arch support, such as arch support <NUM>, may be incorporated into an insole, as discussed further below. In other embodiments, the flexible arch support is a standalone insert that may be used by itself to support just the user's arch.

In some embodiments, a standalone flexible arch support may include one or more layers on one or more of the plantar side <NUM> and the bottom side <NUM> of the arch support. The additional layer or layers may facilitate use of the arch support as a standalone insert. <FIG> illustrates a flexible arch support <NUM>, according to one embodiment, in which a layer <NUM> of material, such as foam and/or gel, is provided on the plantar side <NUM>. An additional layer <NUM>, such as a fabric layer, may be added to the upper side of the layer <NUM>. The foam, gel, and/or fabric layers may provide additional comfort to the user. In some embodiments, the bottom side <NUM> may be provided with a fabric layer, foam layer, and/or gel layer. In some embodiments, the entire flexible arch support is encased in one or more layers of material, such as a foam material. For example, in addition to the foam layer <NUM> on the plantar side <NUM>, the flexible arch support may include a foam layer <NUM> on the bottom side <NUM>. In some embodiments, the bottom side <NUM> is textured or provided with a sticky material to prevent the flexible arch support from sliding in a user's footwear, which may be particularly advantageous for embodiments in which the flexible arch support is a standalone insert since there is less surface area for contacting the footwear. The sticky texturing or material may be provided directly on the bottom surfaces of the second set of ribs or on any layer disposed on the bottom side <NUM> of the flexible arch support.

<FIG> illustrate a right-foot insole <NUM>, according to some embodiments, which includes a flexible arch support according to the principles discussed above. Insole <NUM> is configured to be placed in an article of footwear to provide cushioning and support. Although the figures and following description describe a right-foot insole, it is to be understood that the left-foot insole is generally a mirror image of the right-foot insole and, thus, the features described below pertain to a left-foot insole as well.

Insole <NUM> includes a heel portion <NUM>, a midfoot portion <NUM>, and a forefoot portion <NUM>. The perimeter of insole <NUM> is generally shaped to follow the outline of a typical wearer's foot. Moving from back to front along the insole <NUM>, the forefoot portion <NUM> broadens slightly to a maximum width that is configured to be located generally beneath the broadest portion of a wearer's foot (i.e., beneath the distal heads of the metatarsals). The forefoot portion <NUM> then narrows into a curved end that may be shaped to follow the general outline of the toes of a typical wearer's foot. Moving rearward from forefoot portion <NUM>, the midfoot portion <NUM> and heel portion <NUM> narrow slightly to a curved end configured to follow the outline of a typical wearer's heel.

The forefoot portion <NUM> may be generally flat. In some embodiments, the forefoot portion <NUM> has a uniform thickness. In other embodiments, forefoot portion <NUM> may include a nonuniform thickness with one or more areas of increased thickness that, for example, are located to provide additional support at areas of maximum pressure on a wearer's forefoot. For example, an area of increased thickness may be provided at an area of the forefoot portion <NUM> located proximal to the wearer's second and third metatarsals, which is typically the location of the greatest pressure in the forefoot during the "toe off" phase of a step.

Forward to rearward, the upper surface of the midfoot portion <NUM> is contoured to follow the shape of a wearer's arch. This contour can be achieved, at least in part, by the respective configurations of the sets of ribs of the flexible arch support <NUM>. In some embodiments, at least a portion of the contour of the midfoot portion <NUM> may be achieved by an increase in thickness of a base <NUM> of the insole that the arch support <NUM> is received in.

The midfoot portion <NUM> may be contoured across its width such that one or both of the sides of the midfoot portion <NUM> extend upwardly. The upward extension of the inside <NUM> (medial side) of the midfoot portion (the portion that underlies the arch of a wearer's foot) may be configured to follow the contour of the user's arch. The upward extension of the outside <NUM> (lateral side) of the midfoot portion can provide additional support to the outside of the wearer's foot. The upward extensions of the inside and outside of the midfoot portion <NUM> may be achieved by increased thickness of the base <NUM>, by contouring of the overall midfoot portion <NUM>, and/or by the configuration of the arch support <NUM>.

The heel portion <NUM> is generally cup shaped and configured to underlie a typical wearer's heel. The heel portion <NUM> may include a relatively flat central portion <NUM> and a sloped side wall <NUM> that extends around the sides and rear of the flat central portion <NUM>. Generally, when a heel strikes a surface, the fat pad portion of the heel spreads out. A cupped heel portion thereby stabilizes the heel of the wearer and maintains the heel in the heel portion <NUM>, preventing spreading out of the fat pad portion of the heel and also preventing any side-to-side movement of the heel in the heel portion <NUM>. The thickness of the central portion <NUM> of the heel portion <NUM> may be uniform. The thickness may be uniform with the thickness of the midfoot portion <NUM> or may be greater than or less than the thickness of the midfoot portion <NUM>. In some embodiments, the thickness of the heel portion is nonuniform, for example, with a thicker section located centrally in the heel portion such that the area immediately beneath a wearer's heel provides the most cushioning.

The bottom surface of insole <NUM> (the surface that contacts the footwear into which it is inserted), may or may not include texturing. Texturing may be useful to provide greater grip to the footwear, preventing shifting of the insole <NUM> within the footwear. Texturing may be provided on any of the forefoot portion <NUM>, the midfoot portion <NUM>, and the heel portion <NUM>. In some embodiments, the forefoot portion <NUM> includes one or more pattern trim lines for indicating where to trim the insole <NUM> to fit into smaller size footwear.

The base <NUM> of the insole <NUM> may extend the entire length of insole <NUM>. In some embodiments, a cover layer <NUM> is secured to the upper surface of the base <NUM> along the entire length of the insole <NUM> for contacting a user's foot. The cover layer <NUM> may be secured by any suitable means, such as adhesive, radio frequency welding, etc..

The base <NUM> may be made from any suitable material including, but not limited to, any flexible material that may cushion and absorb the shock from heel strike on the insole. Suitable shock absorbing materials may include any suitable foam, such as, but not limited to, cross-linked polyethylene, poly(ethylene-vinyl acetate), polyvinyl chloride, synthetic and natural latex rubbers, neoprene, block polymer elastomers of the acrylonitrile-butadiene-styrene or styrene-butadiene-styrene type, thermoplastic elastomers, ethylenepropylene rubbers, silicone elastomers, polystyrene, polyuria, or polyurethane; preferably a flexible polyurethane foam made from a polyol chain and an isocyanate such as a monomeric or prepolymerized diisocyanate based on <NUM>,<NUM>'-diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI). Such foams may be blown with fluorocarbons, water, methylene chloride or other gas producing agents, as well as by mechanically frothing to prepare the shock absorbing resilient layer. Such foams advantageously may be molded into the desired shape or geometry. The base <NUM> may be made from block copolymer styrene-ethylene-butylene-styrene (SEBS) or from a combination of SEBS and ethylene-vinyl-acetate (EVA). In some embodiments, the base <NUM> is formed from <NUM>-55N and/or <NUM>-55N SEBS, manufactured by TSRC Corporation of Taiwan. In some embodiments, the base <NUM> is made from a combination of <NUM>-55N SEBS, <NUM>-55N SEBS and EVA. In some embodiments, S19-<NUM> SEBS GEL manufactured by TSRC may be used, 108A/B polyurethane foam manufactured by PVI Chemical Co. of Taiwan may be used, a combination of EVA and 108A/B polyurethane foam may be used, or a combination of any of these materials or any other suitable materials may be used.

Non-foam elastomers such as the class of materials known as viscoelastic polymers, or silicone gels, which show high levels of damping when tested by dynamic mechanical analysis performed in the range of -<NUM> degrees C to <NUM> degrees C may also be advantageously employed. Resilient polyurethane may be prepared from diisocyanate prepolymer, polyol, catalyst and stabilizers that provide a waterblown polyurethane foam of the desired physical attributes. Suitable diisocyanate prepolymer and polyol components include polymeric MDI M-<NUM> (CAS <NUM>-<NUM>-<NUM>) and Polymeric MDI MM-<NUM> (<NPL>), both available from BASF, Parsippany, N. ; Pluracol <NUM> (<NPL>) and Pluracol <NUM>, both available from BASF, Parsippany, N. ; Multrinol <NUM>, available from Mobay, Pittsburgh, Pa. ; MDI diisocyanate prepolymer XAS <NUM> and polyol blend XUS <NUM> available from Dow Chemical Company, Midland, Mich. ; and Niax <NUM>-<NUM>, available from Union Carbide, Danbury, Conn.

These urethane systems generally contain a surfactant, a blowing agent, and an ultraviolet stabilizer and/or catalyst package. Suitable catalysts include Dabco <NUM>-LV (<NPL>,<NPL>), Dabco X543 (CAS Trade Secret), Dabco T-<NUM> (<NPL>), and Dabco TAC (<NPL>) all obtainable from Air Products Inc. , Allentown, Pa. ; Fomrez UL-<NUM>, a stannous octoate, from the Witco Chemical Co. , New York, N. or A-<NUM> (<NPL>) available from OSI Corp. , Norcross, Ga. Suitable stabilizers include Tinuvin <NUM> (<NPL>), Tinuvin <NUM> (<NPL>), Tinuvin <NUM> (<NPL>), Irganox <NUM> (<NPL>), Irganox <NUM> (<NPL>), all available from the Ciba Geigy Corporation, Greensboro, N. , or Givsorb UV-<NUM> (<NPL>) and Givsorb UV-<NUM> (<NPL>) from Givaudan Corporation, Clifton, N. Suitable surfactants include DC-<NUM> (a mixture), DC190 (<NPL>), DC197 (<NPL>), DC-<NUM> (<NPL>) all available from Air Products Corp. , Allentown Pa. and L-<NUM> (CAS trade secret) from Union Carbide, Danbury Conn.

Base <NUM> may be made from a urethane molded material, such as a soft, resilient foam material having Shore Type OO Durometer hardness in the range of <NUM> to <NUM>, as measured using the test equipment sold for this purpose by Instron Corporation of Canton Mass. Preferably the base layer has a Shore Type OO Durometer hardness in the range of <NUM> to <NUM>, and more preferably, in the range of <NUM> to <NUM>. Such materials provide adequate shock absorption for the heel and cushioning for the midfoot and forefoot.

Alternatively, the base <NUM> may be a laminate construction, that is, a multi-layered composite of any of the above materials. Multi-layered composites are made from one or more of the above materials such as a combination of EVA and polyethylene (two layers), a combination of polyurethane and polyvinyl chloride (two layers), or a combination of ethylene propylene rubber, polyurethane foam, and EVA (<NUM> layers). In some embodiments, the base <NUM> is made from a layering of EVA and SEBS.

The base <NUM> may be prepared by conventional methods, such as heat sealing, ultrasonic sealing, radio-frequency sealing, lamination, thermoforming, reaction injection molding, and compression molding, if necessary, followed by secondary die-cutting or in-mold die cuffing. Representative methods are taught, for example, in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>, in <NPL>. ; and <NPL>; Preferably, the insole is prepared by a foam reaction molding process such as is taught in <CIT>. In some embodiments, the base <NUM> is prepared by a conventional direct injection expanded foam molding process. An example of a conventional direct injection molding machine model is KSC908 LE2A, made by King Steel Machinery Co.

The cover layer <NUM> may be made from any suitable material including, but not limited to, fabrics, leather, leatherboard, expanded vinyl foam, flocked vinyl film, coagulated polyurethane, latex foam on scrim, supported polyurethane foam, laminated polyurethane film or in-mold coatings such as polyurethanes, styrene-butadiene rubber, acrylonitrile-butadiene, acrylonitrile terpolymers and copolymers, vinyls, or other acrylics, as integral top covers. Desirable characteristics of the cover layer <NUM> include good durability, stability and visual appearance. It is also desirable that the cover layer <NUM> has good flexibility, as indicated by a low modulus, in order to be easily moldable. The bonding surface of the cover layer <NUM> should provide an appropriate texture in order to achieve a suitable mechanical bond to the upper surface of the base <NUM>. The cover layer <NUM> may be a fabric, such as a brushed knit laminated top cloth (for example, brushed knit fabric/urethane film/non-woven scrim cloth laminate) or a urethane knit laminate top cloth. Preferably, the cover layer <NUM> is made from a polyester fabric material.

In some embodiments, the heel portion <NUM> may include an insert (not shown) that is centrally located in the heel portion <NUM> - the area of the heel portion <NUM> that receives the greatest force from the wearer's heel. The insert can be made of a stiffer material than the material of the base <NUM> to provide additional shock absorption without requiring a large increase in thickness of the heel portion <NUM>. The insert may be secured within a shallow recess on the underside of the base <NUM> and may be secured by any suitable means, such as adhesive, radio frequency welding, etc. The insert may be formed of any suitable material. Suitable synthetic elastomeric polymeric materials comprise for example polymers made from conjugated dienes, for example, isoprene, butadiene, or chlorobutadiene, as well as from co-polymeric materials made from conjugated dienes and vinyl derivatives such as styrene and acrylonitrile. Exemplarily, suitable synthetic rubber materials comprise isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber (SBR), nitrile-butadiene rubber (NBR), also in hydrogenated form, ethylene-propylene-(diene) rubber (EPM, EPBM), ethylene vinyl acetate rubber, silicone rubber also including liquid silicone rubber. The insert can be made of poly(styrene-butadiene-styrene) (SBS), polyurethane foam, EVA, or a combination thereof.

As illustrated in <FIG>, the insole <NUM> includes a flexible arch support <NUM> located in a recess <NUM> in the bottom side <NUM> of the insole <NUM>. The frame <NUM> may extend along the perimeter of the recess <NUM>. The frame <NUM> and the recess <NUM> may be configured so that the lower surfaces of the frame <NUM> are flush with the surrounding portions of the base <NUM>. The upper surfaces of the frame <NUM> may contact the bottom <NUM> of the recess <NUM> and may serve to attach the arch support <NUM> to the base <NUM>. For example, the frame <NUM> may be adhesively fixed to the bottom <NUM> of the recess <NUM> or the base <NUM> may be molded to the frame <NUM>.

In some embodiments, the flexible arch support <NUM> is configured and located in the insole <NUM> so that it is directly beneath the arch of a typical wearer's arch. For example, the flexible arch support <NUM> may be configured and located to extend longitudinally from at least the talus-navicular joint of a typical target wearer's foot to the medial cuneiform-first metatarsal joint and laterally under at least the medial cuneiform bone to support the arch cavity when the flexible arch support is in use.

The first set of ribs <NUM> may extend along the bottom <NUM> of the recess <NUM> and may be affixed to the bottom <NUM>, such as adhesively or through the base being molded to the arch support <NUM>. In some embodiments, the first set of ribs, or at least a portion of the first set of ribs, are not affixed to the bottom <NUM> of the recess <NUM> and may be spaced from the bottom <NUM> of the recess <NUM> when the insole <NUM> is not under load.

The second set of ribs <NUM> are spaced from the bottom <NUM> of the recess <NUM>. The second set of ribs <NUM> may be configured to follow the general front-to-back and side-to-side contouring of the bottom of the base <NUM>. The second set of ribs <NUM> may be configured so that at least a portion of the second set of ribs <NUM> rests against the wearer's shoe when installed in the shoe under no load. In other embodiments, at least one of the second set of ribs <NUM> may be configured to be spaced from the wearer's shoe when installed in the wearer's shoe under no load.

<FIG> illustrates a cross section along a midline <NUM>-<NUM> of the insole <NUM> illustrated in <FIG>. As illustrated, the upper surfaces <NUM> of the second set of ribs <NUM> are lower than the upper surfaces <NUM> of the first set of ribs <NUM>. In the illustrated embodiment, the upper surfaces <NUM> of the second set of ribs <NUM> are spaced from the bottom <NUM> of the recess <NUM>. In this embodiment, through the midline, the upper surfaces <NUM> are lower than the bottom surfaces <NUM> of the first set of ribs <NUM>. Through the midfoot portion <NUM>, the base <NUM> arches upward while the bottom surfaces <NUM> of the second set of ribs follows the contour of the bottom of the base <NUM>. Therefore, ribs of the second set of ribs <NUM> that are in the center of the arch support <NUM> dip lower relative to the bottom <NUM> of the recess <NUM> than the ribs of the second set of ribs <NUM> that are toward the front and rear ends of the arch support <NUM>.

<FIG> illustrates a lateral to medial cross section through one of the ribs of the second set of ribs, along line <NUM>-<NUM> of the insole <NUM> illustrated in <FIG>. In the illustrated embodiment, the rib <NUM>-a curves downward from the portion of the frame <NUM> on the lateral side <NUM> and from the portion of the frame on the medial side. In the center section <NUM>, the rib <NUM>-a is generally flat and uniform. One of the ribs <NUM>-a of the first set of ribs <NUM> may be seen in the background in <FIG>, and, as illustrated, follows along the bottom <NUM> of the recess <NUM>.

<FIG> and <FIG> illustrate an embodiment of an insole and arch support in which the arch support <NUM> is thicker toward the medial side. Arch support <NUM> includes a second set of ribs <NUM> with a maximum curvature <NUM> that is located toward the medial side <NUM> of the arch support <NUM>. <FIG> is a lateral to medial cross section through a rib <NUM>-a of the second set of ribs <NUM>. The lowest point of the rib <NUM>-a is to the medial side of the midline <NUM> of the insole <NUM>. This configuration may provide increased support for a wearer's arch relative to an embodiment in which the profile of the second set of ribs is uniform. In the illustrated embodiment, a rib <NUM>-a of first set of ribs <NUM> has a uniform profile across the center section.

<FIG> illustrates how an insole incorporating the flexible arch support <NUM> may flex to conform to the extreme heel to toe drop of a high heel shoe <NUM>. The gaps <NUM> between adjacent ribs <NUM> enables the arch support <NUM> to bend front to back to follow the large curvature of the high heel shoe <NUM> through the arch <NUM>. However, due to the leaf spring ribs, the arch of the wearer is still supported without a bulky build-up of material.

In some embodiments, the flexible arch support is an "inner layer" of an insole in which one or more layers encase the flexible arch support. <FIG> illustrates an embodiment in which a layer <NUM> of material is provided on the bottom side <NUM> of the insole <NUM>. This layer <NUM> of material may be, for example, a tacky material that could grip the insole <NUM> to the shoe. In some embodiments, the layer <NUM> may be provided across the entire bottom <NUM> of the insole <NUM>, as illustrated in <FIG>, or may only extend beneath a portion of the insole <NUM>, such as beneath just the arch support <NUM>. In some embodiments, the bottom side <NUM> of the insole <NUM> is covered, such as by layer <NUM>, while the plantar side <NUM> is not covered by any material. For example, the base <NUM> may include a cut-out in the midfoot portion <NUM> so that the plantar side <NUM> of the arch support is exposed and the upper surfaces <NUM> of the first set of ribs <NUM> may directly contact a wearer's foot.

In some embodiments, the frame of the flexible arch support may extend beyond the midfoot portion <NUM> to the heal portion <NUM>, for example, to provide additional heel support. <FIG> illustrates an embodiment in which a frame <NUM> of a flexible arch support <NUM> extends into the heel portion <NUM> of the insole <NUM>. In this embodiment, an open ring-like extension <NUM> of the frame <NUM> wraps around a heel portion of the base <NUM> on both the medial and lateral sides (only the medial side is shown). In some embodiments, the extension <NUM> may form a closed ring-like extension.

According to various embodiments, the flexible arch support may be made from thermoplastic material, e.g., thermoplastic polyurethane; foamed materials, e.g. EVA, polyurethane foam; or thermoset materials, e.g., composites. The flexible arch support may be constructed from a thermoplastic olefin polymer that may be stiff and flexible, e.g., polyethylene, polypropylene, polyurethane, or elastomers, or a combination of thermoplastic polyurethane and acrylonitrile-butadiene-styrene. One example may be UH-64D20 thermoplastic polyurethane (TPU) from Ure-tech Company, Cheng-Hwa Hsien, Taiwan, Republic of China. Other examples include: a fiberglass filled polypropylene; nylon; fiberglass; polypropylene; woven extrusion composite; ABS; thermoplastic polymer; carbon graphite; polyacetal, for example, as sold under the trademark "DELRIN" by E. du Pont de Nemours and Company of Wilmington, Del. ; or any other suitable material. The flexible arch support may be made of TPU, for example, TPU having a Shore hardness of about <NUM>±<NUM> Shore A to about <NUM>±<NUM> Shore D. In some embodiments, the flexible arch support is made of a polyamide, such as the polyamide sold under the trademark "Novamid. " The flexible arch support may be 3D printed or injection molded. The flexible arch support may be a unitary piece or may be an assembly of different pieces.

Material thickness of the flexible arch support may be tailored according to the design requirement of a particular application. In some embodiments thickness of the ribs and frame may be generally constant throughout the arch support. In some embodiments, the frame may become thinner toward the outer periphery of the arch support, such as to conform to the contours of an insole into which it is incorporated. In some embodiments, the thickness of each rib is uniform throughout the rib while in other embodiments, the thickness of a rib is non-uniform. For example, the thickness may increase from one end of a rib to a maximum at the center of the rib and then decrease at the opposite end. In some embodiments, at least some of the ribs have the same thickness. For example, all of the first set of ribs may have the same thickness and/or all of the second set of ribs may have the same thickness. In some embodiments, thickness of ribs in the same set of ribs varies. For example, ribs closer to the sides of the flexible arch support may be thinner than ribs at the center at the same relative location on the ribs.

Finite element analysis (FEA) simulations were performed on an example embodiment of the flexible arch support to quantitatively evaluate the flexibility of the flexible arch support embodiment as compared to a conventional flexible arch support design. <FIG> illustrates the configuration of a conventional arch shell used for the simulations. The conventional arch shell has a contoured but generally uniformly rigid shape that acts as a supportive spring under the arch during the stance phase of gait. <FIG> illustrates the configuration of the flexible arch support embodiment used for the simulations. The overall dimensions and curvature of the conventional arch shell and flexible arch support embodiment are the same.

In the simulations, a rigid fixture was applied to the back face of each arch support. A uniform <NUM> Newton force was applied to the front face of each arch support normal to the axial plane of each model. Typical acrylonitrile butadiene styrene (ABS) material properties were applied to each model prior to running the simulation (Young's Modulus = 2e+9N/m<NUM>). The mesh density was balanced with a global mesh size of <NUM> ± <NUM>. The internal stress (von Mises) within each arch support were quantified in N/m<NUM> and the displacement (i.e., flexion) of each arch support were quantified in millimeters.

<FIG> show the FEA results for the von Mises stresses for the conventional arch shell and the flexible arch support embodiment, respectively, and <FIG> show the displacement for the conventional arch shell and the flexible arch support embodiment, respectively. The scales are not the same for the conventional arch shell and the flexible arch support embodiment, but the values are shown on their respective scales. Comparing <FIG>, the minimum von Mises stress was <NUM> times higher for the conventional arch shell as compared to the flexible arch support embodiment.

While the overall maximum von Mises stress was higher in the flexible arch support embodiment, the overall average von Mises stress was higher in the conventional arch shell as compared to the flexible arch support embodiment. This would cause the conventional arch support to resist bending under applied loads more so than the flexible arch support embodiment. In fact, for the simulations, the displacement was <NUM> times greater for the flexible arch support embodiment versus the conventional arch shell. These results demonstrate that, under simulated loading conditions, a flexible arch support embodiment is more flexible than a conventional arch support, which is due at least in large part to the material gaps separating the alternating support ribs. In practice, this flexibility would allow the flexible arch support to conform and move with high fashion footwear to a greater degree as compared to conventional arch shells while providing arch support via the independent and alternating leaf springs ribs.

Ultimately, the perceived comfort of an insole is an important outcome needed to evaluate its ability to improve the fit of high fashion footwear such as high heels or ballet flats. Therefore, initial and extended fit and feel was evaluated in <NUM> healthy female volunteers while wearing high heeled shoes with and without insoles fabricated with an embodiment of an insole having a flexible arch support, according to the principles described above. The subjects compared two insoles embodiments having a flexible arch support to a conventional high heel insole (Dr. Scholl's Stylish Step High Heel Relief Insoles, Bayer Consumer Health, Whippany NJ) during the initial fit and feel wear test.

The dimensions and flexible arch support were equivalent for the two flexible arch support insole embodiments. However, the base materials were different - one was Styrene Ethylene Butylene Styrene (SEBS) gel and the other was Polyurethane foam. Each subject was asked to place a pair of insoles (one of the two flexible arch support insole embodiments or the conventional arch shell insole) in their own high heeled shoes and then take a short walk (approximately <NUM>-<NUM> minutes) followed by a set of initial wear fit and feel questions. This process was repeated for the other two of the three test insoles. The order in which the insoles were worn was randomized between subjects. The consumers were asked to rank the insoles (#<NUM> = best, #<NUM> = worst) on overall comfort after finishing all of the short walks with each of the tested insoles. Each subject was then asked to take home and wear either the gel or foam flexible arch support insole embodiments in their own high heeled shoes. The subjects were sent a set of extended wear fit and feel questions to answer after wearing the insoles for one week.

Greater than <NUM>% of the subjects felt that the flexible arch support insole embodiments were ranked in the top <NUM> (out of three) based on overall comfort as compared to less than <NUM>% for the conventional insoles (P<<NUM>). Approximately <NUM>% of the subjects felt that the flexible arch support insole embodiments were not difficult to install (<NUM>% and <NUM>% for the gel and foam, respectively) into their high heels as compared to <NUM>% for the conventional insole. Approximately <NUM>% of the subjects felt that the flexible arch support insole embodiments were moderately comfortable or better (<NUM>% and <NUM>% for the gel and foam versions, respectively) when they first put their high heels on and stood up as compared to <NUM>% for the conventional insoles (P<<NUM>). Approximately <NUM>% of the subjects felt that the flexible arch support insole embodiments made their shoes more comfortable (<NUM>% and <NUM>% for the gel and foam versions, respectively) after wearing them while walking for three to four minutes as compared to <NUM>% for the conventional insoles (P<<NUM>). Approximately <NUM>% of the subjects were satisfied with the flexible arch support insole embodiments (<NUM>% and <NUM>% for the gel and foam versions, respectively) after wearing them while walking for three to four minutes as compared to <NUM>% for the conventional insoles (P<<NUM>). Finally, approximately <NUM>% of the subjects felt that the flexible arch support insole embodiments fit their arch "Just right" (<NUM>% and <NUM>% for the gel and foam versions, respectively) after wearing them while walking for three to four minutes as compared to <NUM>% for the conventional insoles (P<<NUM>).

Approximately <NUM>% of the subjects felt that the flexible arch support insole embodiments made their high heels more comfortable (<NUM>% for both gel and foam versions) after wearing them in their high heels for one week. Approximately <NUM>% of the subjects were satisfied with the flexible arch support insole embodiments (<NUM>% for both gel and foam versions) after wearing them in their high heels for one week. Approximately <NUM>% of the subjects felt that the flexible arch support insole embodiments fit their arch "just right" (<NUM>% and <NUM>% for the gel and foam versions, respectively) after wearing them in their high heels for one week. Finally, <NUM>% of the women indicated that, if given the opportunity, they would continue wearing the flexible arch support insole embodiments after the study ended.

These results show the efficacy of employing the flexible arch support into an insole embodiment intended to be used in high heels. Overall, the far majority of subjects (≥<NUM>%) felt that the flexible arch support insole embodiments made their shoes more comfortable during both initial and extended wear tests. Significantly, the flexible arch support insole embodiments fit the almost <NUM>% of the subjects arches "just right" after an extended period of wear.

Two multi-center evaluations were conducted to independently evaluate the benefit of high heel insoles and ballet flat insoles each fitted with an embodiment of the flexible arch support.

The multi-center evaluation of the high heel insole was performed to evaluate how high heel insoles fitted with an embodiment of the flexible arch support aided in the relief of pain experienced from wearing high heel shoes. A total of one hundred and eleven (<NUM>) healthy female subjects were screened for study eligibility. Ninety (<NUM>) subjects qualified for study enrollment and eighty-nine (<NUM>) subjects completed the study. The inclusion criteria were women, <NUM>-<NUM> years of age, who have experienced mild to moderate foot pain from wearing high heel shoes at least four days out of a typical week. One pair of high heel insoles with an embodiment of the flexible arch support were evaluated. Subjects were asked to wear the insoles in their shoes for a minimum of eight (<NUM>) hours per day, for a minimum of four days over a one-week period. Pain level, shoe/insole fit, and foot comfort questionnaires were completed.

The reduction in level of foot pain experienced when wearing the insoles fitted with an embodiment of the flexible arch support in high heels is shown in Table <NUM>.

Referring to Table <NUM>, the evaluation column refers to when the questionnaires were completed - baseline (prior to entering the study and donning the insole), immediate (in short period immediately after donning the insole), day <NUM> (after one day of wear), and day <NUM> (after seven days of wear). The N column refers to the number of subjects who completed all four of the questionnaires. The treatment mean refers to the level of foot pain experienced by ladies at each evaluation period ranked on a zero to one-hundred scale where a higher value represents more pain. The mean difference in pain from baseline for each evaluation period is presented as a number value and corresponding percentage change.

Each of the evaluation periods showed significant reductions in pain as denoted by the Within-Treatment t-test p-value column. The percent of subjects who had less pain as compared to baseline was approximately <NUM>%, <NUM>%, and <NUM>%, respectively, for the Immediate, Day <NUM>, and Day <NUM> evaluations. Additionally, the high heel insoles fitted with an embodiment of the flexible arch support improved the immediate fit of high heel shoes in approximately <NUM>% of the subjects (p = <NUM>). Approximately <NUM>% and <NUM>% of the subjects had improved fit after one day (p = <NUM>) and seven days (p = <NUM>) of wear, respectively. Finally, approximately <NUM>% of the subjects reported feeling comfort at baseline without the high heel insoles fitted with the flexible arch support. Approximately <NUM>% of the subjects reported feeling comfort immediately after donning the insoles (p < <NUM>). Furthermore, approximately <NUM>% (p < <NUM>) and <NUM>% (p < <NUM>) of the subjects reported feeling comfort after one day of wear and after seven days of wear, respectively.

The multi-center evaluation of the ballet flat insole was performed to evaluate how ballet flat insoles fitted with an embodiment of the flexible arch support aided in the relief of pain experienced from wearing ballet flat style shoes. A total of forty-six (<NUM>) subjects were screened for study eligibility. Thirty-three (<NUM>) subjects qualified for study enrollment and completed the study. The inclusion criteria were women, <NUM>-<NUM> years of age, who wear ballet flat closed heel shoes (shoes with ≤ <NUM> inches, i.e. ~<NUM>, high) at least four days out of a typical week and who experienced discomfort and foot and leg fatigue when wearing their ballet flat shoes. Subjects were asked to wear the ballet flat insoles fitted with an embodiment of the flexible arch support in their shoes for one week with one extended wear day of approximately <NUM> hours. Subjects assessed the insole for comfort, relief of foot and leg fatigue, foot support and fit.

Improvement in overall foot comfort experienced when wearing insoles fitted with an embodiment of the flexible arch support in ballet flat style shoes is shown in Table <NUM>.

Referring to Table <NUM>, overall foot comfort is shown on a zero to seven-point scale (a higher value representing more comfort) for each evaluation period - baseline (prior to donning the insole), immediate (<NUM>-minute after donning the insole), on day <NUM> after <NUM> hours of use, and on day <NUM> after <NUM> hours of use. The overall foot comfort improved significantly from baseline at each of the evaluation periods (p < <NUM>). Additionally, greater than <NUM>% of the subjects reported that their foot and arch was supported by the insole in their ballet flat style shoes after each evaluation period (immediate, day <NUM>, and day <NUM>).

Although the present invention uses the term "insole," it will be appreciated that the use of other equivalent or similar terms such as "innersole" or "insert" are considered to be synonymous and interchangeable, and thereby, they are included in the presently claimed invention.

Further, although the present invention has been described primarily in connection with removable insoles, the invention can be incorporated directly into the sole of a shoe, and the present invention is intended to cover the same. In this regard, reference is made in the claims to an insole for use with footwear, including a removable insole or an insole built into a shoe. If built into a shoe, for example, the heel portion could be fixed and the mid portion and forefoot portions could be allowed to elongate as the foot flexes.

The foregoing description, for the purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the techniques and their practical applications. Others skilled in the art are thereby enabled to best utilize the techniques and various embodiments with various modifications as are suited to the particular use contemplated.

Claim 1:
An insole (<NUM>) for insertion into footwear, comprising:
a base (<NUM>); and
an arch support (<NUM>) located on an underside of the base (<NUM>), the arch support comprising:
a frame (<NUM>) forming at least a portion of a perimeter of the arch support, and
a plurality of ribs (<NUM>) extending from a first side of the frame (<NUM>) underlying a medial side of the insole base to a second side of the frame (<NUM>) underlying a lateral side of the insole base (<NUM>), wherein a first set of the ribs (<NUM>) is raised relative to a second set of the ribs (<NUM>), wherein the first set of ribs (<NUM>) are positioned between the second set of ribs (<NUM>) to form an alternating array of independent leaf spring ribs, and wherein the first and second set of ribs (<NUM>, <NUM>) forming the alternating array of independent leaf spring ribs are spaced apart by gaps (<NUM>) in their material.