Shoe Insole

Abstract

An insole comprising a cushioning member and a bladder housing a flowable material. The bladder has a proximal forefoot portion, a hindfoot portion, and a lateral midfoot portion. The bladder does not substantially extend over the medial midfoot portion of said cushioning member. The bladder may house hollow microspheres.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present invention relates generally to shoe insoles or inserts, and more particularly to insoles having a bladder with a flowable material housed therein.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to an insole for insertion into footwear. The insole comprises a cushioning member having a forefoot portion, a hindfoot portion, and a midfoot portion which connects the forefoot portion and the hindfoot portion together. The insole also comprises a bladder connected to or overlying the cushioning member. The bladder houses a flowable material. The bladder has a proximal forefoot portion, a hindfoot portion, and a lateral midfoot portion which connects the proximal forefoot portion of the bladder and the hindfoot portion of the bladder together. The bladder does not substantially extend over the medial midfoot portion of the cushioning member.

In another aspect, the insole includes a secondary forefoot cushioning member located adjacent the forefoot portion of the cushioning member. In yet another aspect, the cushioning member and the secondary forefoot cushioning member are comprised of the same material.

In a further aspect, the cushioning member comprises a foam member.

In still another aspect, the forefoot portion of the cushioning member is thicker than the hindfoot portion of the cushioning member and the midfoot portion of the cushioning member.

In another aspect, the flowable material comprises microparticles in a carrier. The microparticles may, for example, comprise hollow microspheres.

In another aspect of the present invention, the insole comprises a cushioning member having a forefoot portion, a hindfoot portion, and a midfoot portion which connects the forefoot portion and the hindfoot portion together. A bladder is connected to the cushioning material and the bladder houses a flowable material comprising hollow microspheres.

In yet another aspect, the hollow microspheres are comprised of a vinylidene chloride, polypropylene, or acrylonitrile polymer or copolymer. In a further aspect, the hollow microspheres are comprised of glass, ceramic, or plastic. In another aspect, the hollow microspheres have a crush strength of up to about 2000 psi, for example. In still another aspect, the hollow microspheres have a particle size of about 500 microns or less, e.g., about 100 to 350 microns.

In yet another aspect, the flowable material inside the bladder has a density of about 0.3 to 1.0 g/cm³. In still another aspect, the flowable material has a viscosity of about 3000 to 70,000 cp.

In another aspect of the present invention, the cushioning member has a recess for receiving the bladder. The cushioning member has a first major face and a second major face, and the recess is located in the second major face. When the bladder is received within the recess such that the bladder extends beyond the second major face of the cushioning member.

Additional aspects of the invention, together with the advantages and novel features appurtenant thereto, will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a skeletal outline, illustrating a dorsal view of the bones of the human foot. The general location of the forefoot, midfoot, and hindfoot is illustrated. FIG. 1B is a plan view of an imprint of a human foot, illustrating the general location of the medial and lateral portions of the human foot.

FIG. 2 is a bottom plan view of an insole in accordance with a first exemplary embodiment of the present invention.

FIG. 3 is a cross-section of the insole illustrated in FIG. 2, taken through line 3′-3′.

FIG. 4 is a cross-section of the insole illustrated in FIG. 2, taken through line 4′-4′.

FIG. 5 is an exploded view of an insole in accordance with a second exemplary embodiment of the present invention. The bladder containing the flowable material is shown separately from the cushioning member. Further, an opening in the bladder used to fill the bladder with flowable material is shown. This opening is sealed prior to insertion of the bladder in to the recess of the cushioning member. In addition, the excess material around the opening may be removed after sealing so that the bladder fits snuggly into the recess.

FIG. 6 is a cross-section of the insole illustrated in FIG. 5, taken through line 6′-6′ after the bladder containing the flowable material is placed in a recess in the cushioning member.

FIG. 7 is a cross-section of the insole illustrated in FIG. 5, taken through line 7′-7′ after the bladder containing the flowable material is placed in a recess in the cushioning member.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The insoles of the present invention are designed to be used with shoes worn by a human foot. Turning now to the drawings, FIGS. 1A and 1B illustrate the structure of the human foot. Generally speaking, the foot comprises (i) a hindfoot region containing the talus 1 and os calcis 2 bones; (ii) a midfoot region containing the cuneiform 3, cuboid 4 and navicular 5 bones; and (iii) a forefoot region comprising the metatarsals 6, the proximal phalanges 7, and the middle 8 and distal 9 phalanges.

As shown in FIG. 1B, the hindfoot region can be divided into two sub-regions: the medial hindfoot (or medial heel) region and the lateral hindfoot (or lateral heel) region. The midfoot region can be divided into two sub-regions: the medial midfoot region and the lateral midfoot region. The forefoot region can be divided into two sub-regions: the distal sub-region comprising the middle and distal phalanges, and the proximal forefoot region comprising the metatarsals and proximal phalanges. The foot also includes a longitudinal arch, having a medial and a lateral side. The medial longitudinal arch is generally defined by the navicular and medial cuneiform bones of the midfoot and the about the proximal half of the first, second, and third metatarsals.

In FIGS. 2 to 4, a first embodiment of the insole 10 of the present invention is shown. The exemplary insole 10 is designed to fit the shape of a human right foot. An insole designed to fit the shape of a human left foot may be constructed in a similar manner, and will typically be the mirror image of the exemplary insole 10 for the right foot.

In general, the insole 10 comprises a forefoot portion 12, a hindfoot portion 16, and a midfoot portion 14 which connects the forefoot portion 12 and the hindfoot portion 16 together. The insole 10 comprises a cushioning member 20, a secondary distal forefoot cushioning member 30, and a bladder 40 housing a flowable material 50. The size and shape of the bladder 40 is designed to provide cushioning for the foot of the user so that the ball and heel of the foot does not hit an incompressible material during normal use.

The cushioning member 20 comprises a forefoot portion 22, a hindfoot portion 26, and a midfoot portion 24 which connects the forefoot portion 22 and the hindfoot portion 26 together. The midfoot portion 24 of cushioning member 20 includes both a medial midfoot portion 24M and a lateral midfoot portion 24L. The cushioning member 20 is preferably generally planar and has a first major face 20A (e.g., the upper face when the insole is in normal use) and a second major face 20B (e.g., the lower face when the insole is in normal use). The thickness of the cushioning member 20 is preferably about 2 to 4 mm (e.g., about 2.0, 2.2., 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, or 4.0 mm or some range therebetween). The cushioning member 20 may optionally curve upward at the peripheral edges, especially at the peripheral edges of the midfoot portion and hindfoot portion, of the insole in order to create a cradle for the side, heel, and arch of the foot. In addition, a backing (such as a leather, cloth, or other fabric or hardened skin as set forth in Marc, U.S. Pat. No. 7,837,910 which is incorporated by reference) may optionally be placed around the cushioning member 20 or over second major face 20A.

Any suitable cushioning material may be used to form the cushioning member 20, including, but not limited to, any flexible material which can cushion and absorb the shock from heel strike on the insole. Suitable shock absorbing materials can include any suitable closed or open cell foam, including but not limited to, cross-linked polyethylene, poly(ethylene-vinyl acetate), polyvinyl chloride, synthetic and natural latex rubbers, neoprene, block polymer elastomer of the acrylonitrile-butadiene-styrene or styrene-butadiene-styrene type, thermoplastic elastomers, ethylenepropylene rubbers, silicone elastomers, polystyrene, polyurea or polyurethane; most preferably a polyurethane foam made from flexible polyol chain and an isocyanate such as a monomeric or prepolymerized diisocyanate based on 4,4′-diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI). Such foams can be blown with freon, water, methylene chloride or other gas producing agents, as well as by mechanically frothing to prepare the shock absorbing resilient layer. Such foams advantageously can be molded into the desired shape or geometry.

The secondary forefoot cushioning member 30 comprises a forefoot portion, preferably a distal forefoot portion, adapted to be located by the forefoot of the user during normal use. The secondary forefoot cushioning member 20 is preferably generally planar and has a first major face 30A (e.g., the upper face when the insole is in normal use) and a second major face 30B (e.g., the lower face when the sole is in normal use). The thickness of the cushioning member 30 is preferably about 3 to 4 mm (e.g., about 3.0, 3.2, 3.4, 3.6, 3.8, 4.0 mm or some range therebetween).

The secondary forefoot cushioning member 30 may be attached to the cushioning member 20 using any conventional means, e.g., adhesive, heat sealing, welding, stitching, cementing, and the like. The materials used to form the cushioning member 20 and the secondary forefoot cushioning member 30 may be the same or different.

Exemplary methods for forming the cushioning member 20 and the secondary forefoot cushioning member 30 are set forth in Marc, U.S. Pat. No. 7,837,910 titled “Method of Forming a Hardened Skin on a Surface of a Molded Article”; Marc, U.S. Pat. No. 7,232,299 titled “Flow Molding Apparatus with Multiple Layers of Molds and Electrodes”; Marc, U.S. Patent Application No. 2006/0012083 titled “Method of Making a Molded Article From Two or More Different Formable Materials in a Single Heating Cycle”; Marc, U.S. Pat. No. 4,268,238 titled “Flow Molding”; Marc, U.S. Pat. No. 4,441,876 titled “Flow Molding”; Marc, U.S. Pat. No. 4,524,037 titled “Method and Apparatus for Forming a Flexible Thermoplastic Resin Foam Article”; Marc, U.S. Pat. No. 4,851,167 titled “Molding Process and Apparatus”; and Marc, PCT Patent Application No. PCT/US2011/023119 titled “Composite Foam Product,” which are all incorporated by reference in their entirety.

The insole of the present invention also comprises a bladder 40 having a first major side 40A (e.g., the side facing upward when the insole is in normal use) and a second major side 40B (e.g., the side facing downward when the insole is in normal use). The bladder 40 houses a flowable material 50 as discussed more fully below. The bladder 40 comprises a proximal forefoot portion 42, a hindfoot portion 46, and a lateral midfoot portion 44L which connects the proximal forefoot portion 42 and the hindfoot portion 46 together. The proximal forefoot portion 42 is generally sized and shaped for receiving the impact generated from the ball of the user's foot during normal use. The hindfoot portion 46 of the bladder 40 is generally shaped for receiving the impact generated from the heel of the user's foot during normal use. As shown in FIG. 2, the bladder 40 is shaped so that it does not overlie or cover the medial midfoot portion and distal forefoot portion of the user's foot. The bladder 40 extends between the heel and the ball of the foot, but does not extend substantially over the medial midfoot subregion of the foot.

The thickness of the bladder from the first major side to the second major side is preferably about 6 to 8 mm (e.g., about 6.0, 6.5, 7.0, 7.5, 8.0 mm or some range therebetween). The cross-sectional area of the lateral midfoot portion 44L of the bladder may vary and can be optimized depending on the viscosity and density of the flowable material and the desired cushioning effect to be provided by the bladder. In general the cross-sectional area of the lateral midfoot portion 44L ranges from about 0.5 to 2 cm² (e.g., about 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 cm²or some range therebetween), with 1 to 1.5 cm² being most preferred. The volume of the bladder is preferably about 30 and 110 cm³ depending on the shoe size (e.g., about 30, 40, 50, 60, 70, 80, 90, 100, 110 cm³ or some range therebetween).

The bladder 40 is comprised of a flexible material. As a result, the bladder is compressible when a force is applied thereto. The bladder also provides a barrier to prevent the passage flowable material contained therein. In selecting materials for the bladder 40, engineering properties of the material (e.g., tensile strength, stretch properties, fatigue characteristics, dynamic modulus, and loss tangent) may be considered. An example of suitable bladder materials are thermoplastic polyurethane (“TPU”) and polyvinyl chloride (“PVC”). In addition to TPU and PVC, examples of polymer materials that may be suitable for the bladder 40 include urethane, polyester, polyester polyurethane, polyether polyurethane, rubber, and synthetic rubber. The bladder 40 may also be formed from materials described in Mitchell et al., U.S. Pat. Nos. 5,713,141 and 5,952,065; Bonk et al., U.S. Pat. Nos. 6,082,025 and 6,127,026; Rudy, U.S. Pat. Nos. 4,183,156, 4,219,945, 4,936,029, and 5,042,176.

The flowable material 50 housed within the bladder is a non-gaseous liquid, paste, gel, cream, putty, colloid, or slurry. The flowable material preferably has a low density so that it will not undesirably add excess weight to the insole and shoe. The density of the flowable material is preferably about 0.1 to 1.0 g/cm³ (e.g., about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 g/cm³ or some range therebetween) with densities of about 0.3 to 0.5 g/cm³, being most preferred. The viscosity of the flowable material is preferably about 500 to 70,000 cp (e.g., about 500, 1000, 1500, 2000, 2500, 3000, 5000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000 cp or some range therebetween), with viscosities of 3000 to 10,000 cp (e.g., 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10,000 cp or some range therebetween) being most preferred. Preferably, it is desirable to use a flowable material of relatively high viscosity such as a mineral oil or a higher alcohol or ester. Of course, any flowable material may be employed which satisfies the requirements of viscosity and compatibility with materials of construction. For example, if the insole is constructed of PVC, one would not employ flowable material which is a solvent for PVC or which would leach out the PVC.

Exemplary flowable materials include various nongaseous media, including but not limited to water; alcohols such as ethanol, isopropanol, n-hexanol, cyclohexanol, trichloroethanol, lauryl alcohol, n-octanol, and n-decanol; esters such as ethyl acetate, isopropyl formate, methyl and ethyl propionate, and isopropyl acetate; halogenated compounds such as dichloroethylene, chloroform, and carbon tetrachloride; and oils such as mineral oil and silicon oil.

In a preferred aspect, the flowable material comprises a plurality of microparticles. The microparticles are preferably dispersed in a carrier. The microparticles typically comprise about 20 to 80% by volume (e.g., about 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80%, by volume or some range therebetween) of the flowable material.

The microparticles used in within the bladder may be rigid or compressible microspheres, or mixtures thereof. Suitable microspheres for use in the bladder according to the invention can be hollow microspheres (also known as microballoons or microbubbles) or solid microspheres. Hollow microspheres are generally preferred. The hollow microspheres increase the viscosity of the flowable material in the bladder and have relatively low densities. Thus, the use of hollow microspheres does not undesirably add too much weight to the insole and shoe. The preferred densities of the hollow microspheres about 0.01 to 0.5 g/cm³ (e.g., about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5 g/cm³ or some range therebetween) with densities of about 0.03 to 0.15 g/cm³, being most preferred.

The microspheres may be made of inorganic materials, such as glass, ceramic, and carbon, or organic polymers, such as phenolic resins and plastics. The microspheres may be surface treated, coated, or colored, as desired. Solid microspheres can be prepared by any of several methods known in the art. For example, solid microspheres can be prepared by softening irregularly shaped particles just enough for them to flow into spheres under the influence of surface tension, by quenching a melt in a cooler medium, or by carrying out polymerizations in well-stirred suspensions at elevated temperature. Hollow inorganic microspheres can be prepared by several known methods. For example, hollow glass spheres can be prepared by grinding and sizing soda-lime glass cullet to form particles that, in combination with blowing agents, are passed through a gas flame to soften the glass and generates gases that expand the particles. See Beck et al., U.S. Pat. No. 3,365,315. Hollow glass spheres can also be prepared by spray-drying a sodium borosilicate solution containing a blowing agent to form a particulate material that is passed through a gas flame to form the spheres. See Veatch et al., U.S. Pat. No. 2,978,339. Ceramic microspheres can be obtained as both solid and hollow microspheres as a normal aluminosilicate by-product of burning coal. See also, J. F. Plummer, “Microspheres” in Encyclopedia of Polymer Science and Technology, Vol. 9, 788 (John Wiley & Sons, Inc.) (1987), which is incorporated by reference.

Microspheres are also generally described in Cravens, U.S. Pat. No. 4,038,238; Melber et al., U.S. Pat. No. 4,829,094; Melber et al., U.S. Pat. No. 4,843,104; Melber, U.S. Pat. No. 4,902,722; Janda, U.S. Pat. No. 4,959,395; and Japanese Patent Publication 60-244511. Commercially available microspheres include the Dualite® family, such as Dualite® M6032 AE or E065-135D, available from Henkel (Greenville S.C.); the Expancel® family, such as the 551 DE or 099 DE80, available from AkzoNobel Industries; and the Z-Light or ceramic Scotchlite glass bubbles available from 3M, including both the K and S series. Such commercially available microspheres may be expanded, hollow microspheres consisting of a thin shell of a vinylidene chloride, polypropylene, or acrylonitrile polymer or copolymer. The shell, for example, may be acrylonitrile/acrylate copolymers or vinylidenechloride/acrylonitrile copolymers. The interior of the Dualite® and ^Expancel® microspheres contains a volatile liquid, such as a low-boiling hydrocarbon (for example, which may be pentane for Dualite® microspheres and which may be isobutane for Expancel® microspheres), which is used to expand the microsphere and remains inside the shell thereafter. An organic or inorganic material that decomposes upon only moderate heating will also serve to expand the microsphere, with the decomposition products remaining in the shell thereafter. Also present on the outside of Dualite® microspheres is a rough coating of calcium carbonate dust.

The microparticles (and the microspheres) housed in the bladder of the present invention preferably have particle sizes of 500 microns or less (e.g., about 500, 450, 400, 350, 300, 250, 200, 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, 15, 10, 6, 5, 4, 3, 2, or 1 microns or less). In addition, the hollow microspheres used may have different particle sizes, for example from about 15 microns to about 350 microns. Microspheres can be purchased with a variety of wall thicknesses, with a thickness of about 1 to 3 microns (e.g., about 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0 microns or some range therebeween) being most preferred. The microspheres can also be characterized by their crush strength, with preferred crush strengths ranging from about 100 to 2000 psi (e.g., about 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000 psi or some range therebetween).

The most preferred commercially available microspheres are the Dualite E065-135D microspheres (Henkel, Greenville, S.C.), which comprise an acrylonitrile copolymer shell with a calcium carbonate coating. These microspheres reportedly have a density of 0.065 g/cm³ and a particle size between 125 and 145 microns. Other preferred commercially available microspheres are Scotchlite K15 glass bubbles (3M). These microspheres reportedly have a density of about 0.15 g/cm³ and 300 psi crush strength. Glass microspheres are also available from Larand Chemical (Boca Raton, Fla.).

The carrier for the microspheres is preferably one of the liquid media described previously. The carrier preferably has a low density so that it will not undesirably add excess weight to the insole and shoe. The density of the carrier is preferably about 0.3 to 1.0 g/cm³ (e.g., about 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 g/cm³ or some range therebetween) with densities of about 0.3 to 0.5 g/cm³ being most preferred. The viscosity of the carrier is preferably about 0.5 to 70,000 cp (e.g., 0.5, 3, 5, 20, 30, 50, 100, 350, 500, 1000, 1500, 3000, 5000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000 cp or some range therebetween), with viscosities of 0.5 to 10,000 cp (e.g., about 50, 100, 350, 500, 1000, 1500, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10,000 cp or some range therebetween) being most preferred. Preferably, it is desirable to use a carrier of relatively high viscosity such as a mineral oil or a higher alcohol or ester. Of course, any carrier may be employed which satisfies the requirements of viscosity and compatibility with materials of construction.

Most preferably, the carrier is a silicone rubber fluid, such as the Rhodorsil oils, and especially the Rhodorsil V-50 (47V50) available from Bluestar Silicones (Cranbury, N.J.). This product has a reported density of 0.96 g/cm³ and a viscosity of 50 cp.

A preferred exemplary flowable material comprises 43% by volume of Rhodorsil V-50 (47V50) silicon oil and 57% by volume of Dualite E065-135 microspheres.

The bladder housing the flowable material can be formed using any method known to those skilled in the art. Preferably, the bladder is formed by placing a vacuum-formed film comprising the bladder material in a mold which has a recess the shape of second major side of the bladder. Another film of similar size is placed on top of that film. The two films are then welded together using an alternating electric field generated, preferably in the radiofrequency range. A small unsealed area 141 is maintained, and this unsealed area is used to inject the flowable material into the bladder. The bladder is preferably filled with the flowable material, typically by using an air cylinder filled with the flowable material. The injector (which is typically a flexible tubing as long as the bladder) on the air cylinder is preferably placed near the bottom of the bladder so that as the bladder fills up with the flowable material, all of the air is removed. Once the bladder is filled with the flowable material, the bladder's unsealed area may be sealed, typically using an alternating electric field or by heat sealing. Any residual or excess material from the now sealed injection opening may be removed (e.g., by cutting away) so that the bladder fits the recess 128. An alternating electric field, preferably in the radiofrequency range, may be used to bond together the cushioning member 20 and the secondary forefoot cushioning member 30 and the bladder 40. All three elements maybe bonded together in a single step, or in separate steps. Exemplary alternating electric field technologies are described generally in Marc, U.S. Published Patent Application No. 2006/0012083 titled “Method of Making a Molded Article from Two or More Different Formable Materials in a Single Heating Cycle” and U.S. Pat. No. 4,441,876 titled “Flow Molding,” which are all incorporated by reference in their entirety.

Use of the insole of the present invention will now generally be described. In general the insole sized and shaped to be inserted into a shoe. When walking, the heel of the person contacts the hindfoot portion of the insole with the heel of the foot, which causes the flowable material located in the hindfoot portion 46 of the bladder 40 to generally move through the lateral midfoot portion 44L towards the proximal forefoot portion 42. Preferably, there is little flowable material residing in the hindfoot portion 46, although the amount of material depends on the area of passage through the lateral midfoot portion, the viscosity of the flowable material, and the force of impact between the person's heel and the bladder. For larger cross-sectional areas in the passage through the lateral midfoot portion, the viscosity of the flowable material may be higher.

When the load leaves the heel and is transferred to the ball of the user's foot, this causes the flowable material to leave the proximal forefoot portion 42 and travel through the lateral midfoot portion 44L towards the hindfoot portion 46. Preferably, there is little flowable material residing in the proximal forefoot portion 42, although the amount of material depends on the area of passage through the lateral midfoot portion, the viscosity of the flowable material, and the force of impact between the ball of the person's foot and the bladder. Generally speaking, the insole operates on the same principle as a shock absorber in a car.

In FIGS. 5 to 7, a second embodiment of the insole 110 of the present invention is shown. The insole 110 is designed to fit the shape of a human right foot. An insole designed to fit the shape of a human left foot may be constructed in a similar manner, and will typically be the mirror image of the exemplary insole 110.

In general, the insole 110 comprises a forefoot portion 112, a hindfoot portion 116, and a midfoot portion 114 which connects the forefoot portion 112 and the hindfoot portion 116 together. The insole 110 comprises a generally planar cushioning member 120 which is integrally formed with a thicker secondary forefoot cushioning region 130. That is, the forefoot cushioning region 130 and the remainder of the cushioning member are formed of a unitary material. A bladder 140 housing a flowable material 150 is inserted into a recess 128 in the cushioning member 120. The size and shape of the bladder 140 is designed to provide cushioning for the foot of the user so that the ball and heel of the foot does not hit an incompressible material during normal use.

The cushioning member 120 comprises a forefoot portion 122, a hindfoot portion 126, and a midfoot portion 124 which connects the forefoot portion 122 and the hindfoot portion 126 together. The midfoot portion 124 of cushioning member 120 includes both a medial midfoot portion 124M and a lateral midfoot portion 124L. The cushioning member 20 has a first major face 120A (e.g., the upper face when the insole is in normal use) and a second major face 120B (e.g., the lower face when the insole is in normal use). The thickness of the cushioning member 120 is preferably about 2 to 5 mm (e.g., about 2, 3, 4, 5 mm or some range therebetween). As shown in FIG. 6, the cushioning member 120 is generally planar, although the peripheral edges 129 generally curve upward. The forefoot portion 122 is thicker than the rest of the cushioning member 120 and functions as the secondary forefoot cushioning region.

The cushioning member 120 includes a recess 128 for receiving the bladder 140. The recess 128 is sized and shaped to fit the size and shape of the bladder 140. As shown in FIGS. 6 and 7, the depth of the recess 128 is such that the bladder 140 generally extends beyond the second major face 120B of the cushioning member 120.

The bladder 140 has a first major side 140A (e.g., the side facing upward when the insole is in normal use) and a second major side 140B (e.g., the side facing downward when the insole is in normal use). The bladder 140 houses a flowable material 150 as discussed previously. The bladder 140 comprises a proximal forefoot portion 142, a hindfoot portion 146, and a lateral midfoot portion 144L which connects the proximal forefoot portion 142 and the hindfoot portion 146 together. The proximal forefoot portion 142 is generally sized and shaped for receiving the impact generated from the ball of the user's foot during normal use. The hindfoot portion 146 of the bladder 140 is generally shaped for receiving the impact generated from the heel of the user's foot during normal use. As shown in FIG. 5, the bladder 140 is shaped so that it does not overlie or cover the medial midfoot portion and distal forefoot portion of the user's foot. The bladder 140 extends between the heel and the ball of the foot, but does not extend over the medial midfoot subregion of the foot.

It will be appreciated that the size and shape of the bladders 40/140 described herein may vary, provided the bladder does not extend substantially over the medial midfoot region of the foot. That is, the size and/or shape of the proximal forefoot region 42/142 of the bladder may vary. Likewise, the size and/or shape of the hindfoot region 46/146 of the bladder may vary. Still further, the size/shape of the lateral midfoot portion of 44L/144L of the bladder may vary, provided that the bladder does not extend substantially over the medial midfoot region of the foot. In various aspects, bladder does not extend over about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% the medial midfoot region of the foot generally illustrated in FIG. 1B. In another aspect, the bladder does not extend substantially over the longitudinal arch of the user during normal use. In various aspects, bladder does not extend over about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the longitudinal arch of the user.

From the foregoing it will be seen that this invention is one well adapted to attain all ends and objectives hereinabove set forth, together with the other advantages which are obvious and which are inherent to the invention. Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative, and not in a limiting sense. While specific embodiments have been shown and discussed, various modifications may of course be made, and the invention is not limited to the specific forms or arrangement of parts and steps described herein, except insofar as such limitations are included in the following claims. Further, it will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

Claims

1. An insole for insertion into footwear, said insole comprising:

a cushioning member having a forefoot portion, a hindfoot portion, and a midfoot portion which connects the forefoot portion and the hindfoot portion together, wherein said midfoot portion includes a medial midfoot portion and lateral midfoot portion;

a bladder connected to said cushioning member, said bladder housing a flowable material, said bladder having a proximal forefoot portion, a hindfoot portion, and a lateral midfoot portion which connects the proximal forefoot portion of said bladder and the hindfoot portion of said bladder together and wherein said bladder does not substantially extend over said medial midfoot portion of said cushioning member.

2. The insole of claim 1 further comprising a secondary forefoot cushioning member located adjacent said forefoot portion of said cushioning member.

3. The insole of claim 2 wherein said cushioning member and said secondary forefoot cushioning member are comprised of the same material.

4. The insole of claim 1 wherein said cushioning member comprises a foam member.

5. The insole of claim 1 wherein said forefoot portion of said cushioning member is thicker than said hindfoot portion of said cushioning member and said midfoot portion of said cushioning member.

6. The insole of claim 1 wherein said flowable material comprises microparticles in a carrier.

7. The insole of claim 6 wherein said microparticles comprise hollow microspheres.

8. The insole of claim 7 wherein said hollow microspheres are comprised of a vinylidene chloride, polypropylene, or acrylonitrile polymer or copolymer.

9. The insole of claim 7 wherein said hollow microspheres are comprised of glass, ceramic, or plastic.

10. The insole of claim 7 wherein said hollow microspheres have a crush strength of up to about 2000 psi.

11. The insole of claim 7 wherein said hollow microspheres have a particle size of about 500 microns or less.

12. The insole of claim 7 wherein said hollow microspheres have a particle size of about 100 to 350 microns.

13. The insole of claim 1 wherein said flowable material has a density of about 0.3 to 1.0 g/cm3.

14. The insole of claim 1 wherein said flowable material has a viscosity of about 3000 to 70,000 cp.

15. The insole of claim 1 wherein said cushioning member has a recess for receiving said bladder.

16. The insole of claim 15 wherein said cushioning member has a first major face and a second major face, and wherein said recess is located in said second major face, and wherein said bladder is received within said recess such that the bladder extends beyond the second major face of the cushioning member.

17. An insole for insertion into footwear, said insole comprising:

a cushioning member having a forefoot portion, a hindfoot portion, and a midfoot portion which connects the forefoot portion and the hindfoot portion together, wherein said midfoot portion includes a medial midfoot portion and lateral midfoot portion;

a bladder connected to said cushioning material, said bladder housing a flowable material comprising hollow microspheres.

18. The insole of claim 17 wherein said microspheres are in a carrier.

19. The insole of claim 17 wherein said hollow microspheres are comprised of a vinylidene chloride, polypropylene, or acrylonitrile polymer or copolymer.

20. The insole of claim 17 wherein said hollow microspheres are comprised of glass, ceramic, or plastic.

21. The insole of claim 17 wherein said hollow microspheres have a crush strength of up to about 2000 psi.

22. The insole of claim 17 wherein said hollow microspheres have a particle size of about 500 microns or less.

23. The insole of claim 17 wherein said hollow microspheres have a particle size of about 100 to 350 microns.

24. The insole of claim 17 wherein said hollow microspheres have a density of about 0.3 to 1.0 g/cm3.

25. The insole of claim 17 wherein said flowable material has a viscosity of about 3000 to 70,000 cp.