Dynamic Insole

Abstract

A dynamic insole that flexes and returns as the plantar fascia flex and return, comprising a medial first windlass-shaped front cutout for great toe phalanges and a lateral second diagonal-shaped front cutout for fourth and fifth toe phalanges, further comprising medial and lateral upwardly-curved side walls wherein a medial side wall comprises a lobe, and made from a first material having a hardness value between 40 Shore A and 90 Shore A.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

Not applicable.

BACKGROUND

The embodiments of the present invention satisfy the needs of having a dynamic insole that discourages pronation, of allowing plantar bands to lengthen and shorten as a wearer walks, provides arch support, reduces metatarsal head pressure, distributes overall loads, and supports the navicular bone.

Information relevant to attempts to address these problems can be found in U.S. Pat. Nos. 6,453,578; 6,604,301; 6,871,422; 6,976,322; 7,010,869; 7,707,751; 7,827,703; 7,832,119; 8,453,346; 8,667,716; 8,800,168; and U.S. Patent Application 2009/0172972; which are not admitted to be prior art with respect to the present invention by its mention in this Background Section. However, it is desirable to have a better apparatus than is disclosed in the references.

U.S. Pat. No. 7,832,119 claims a first metatarsal head lift, but it neither discloses nor claims a lift for the other metatarsal heads nor a cutout for phalanges. The insole in the present invention extends to just behind (anterior to, closer to the ankle than to the toe) metatarsal heads I through V.

U.S. Pat. No. 8,667,716 claims a metatarsal insert slot for inserting a wedge under all five metatarsal heads. In the present invention, the great toe cutout allows the metatarsal pad or engagement surface to be thinner or lower than can be accomplished with a wedge, which can increase wearer comfort.

Podiatrists frequently treat patients for damaged plantar fasica. Fascia is a tissue, like tendons, that connects directly to the bone. Fascia need stress and release, but under constant stress fascia can become irritated. Stress is caused not by the duration of standing, but by how a person stands, e.g., with repetitive movements to the right that overextend due to poor posture such that the right foot supinates under the load and the left foot pronates under the load and the left arch collapses and the left plantar fascia overextends. Thus at a basic level what is needed is a dynamic insole that helps fascia stress and release.

When a person walks, they land on their heels and roll forward towards the toes. At the heel landing, muscle memory pulls the toes back such that all five digital slips of the plantar fascia are extended and tight. As the foot rolls towards the mid-step, the foot is in a supinating position. The three small toes (toes III-V) and their respective plantar fascia then relax, in the order V-IV-III. At mid-toe, the foot starts moving towards a pronating position. At the end of the step, when all five toes are on the ground and the heel is off the ground, if there is poor arch support then all plantar fascia remain tight and are extended due to the arch's fallen position. Thus what is specifically needed is a dynamic insole that anatomically appropriately flexes and releases when a wearer is walking, running or shifting loads on the foot; and that flexes and returns as the plantar fascia flex and return, while supporting the arch.

The present invention supports the arch by means of a medial arch support and by means of toe cutouts that allow the metatarsal heads to sink into the insole, such that the arch curvature is increased and the plantar fascia release and relax. The toe cutouts allow the metatarsal heads to fall, and as they fall the curvature of the arch is able to increase. As the metatarsal heads fall, the insole deflects downwards and then spring back to the first undeflected position. The insole is able to deflect or flex downwards, and then return, because it is made of a material having a hardness that allows insole acts as a flexible springboard. This flexing and returning enables an even greater release and return of planta fascia than otherwise.

The embodiments of the present invention are made to flex and release with the movement of the foot. The elements of the invention that make it dynamic are primarily the toe cutouts and the material hardness. The insole comprises a windlass-shaped front cutout at the great toe, and a diagonal-shaped front cutout at the fourth and fifth toes. The insole further comprises a material having a durometer hardness value of between 40 and 90 Shore A, such that the insole deflects under the application of weight but then returns or springs back to its original position. This durometer is at least approximately 20 units higher than the typical factory-supplied insole of 20 Shore A. The higher durometer also enables the sidewalls to remain upwardly-curved. The insole thicknesses also taper down into the insole edges, which renders the insole more flexible than otherwise. The toe cutouts are shaped to bring the insole distal tip up to points that are just proximal and anterior to the metatarsal heads; these termination points ensure that the metatarsal heads can fall under the weight of the foot. The front windlass cutouts that extend into the upwardly-curved sidewalls are made, by means of their tapered thickness and their 40 to 90 Shore A material, to fall under a wearer's weight and then to spring back to support the return of the toes. Toe cutouts, rather than material or wedges to raise metatarsal heads, are used because the more the toes fall, the more the toe relaxes; and the more the toe relaxes, the more the plantar fascia releases and relaxes. This compression and return at the metatarsal heads, in combination with the cutouts, allow the plantar fascia to flex and release and support the return. In other words, the front of the insole acts as a diving board or springboard.

The embodiments of the present invention discourage pronation through arch support. The insole's arch section side wall is built with a side lobe that comprises sufficient excess material to prevent it from collapsing under the weight of a user. In combination with the flex and release of the insole due to the durometer, this lobe helps the arch pop back up when the foot releases from a flex. The lobe-supported arching also benefits the plantar fascia, because the higher the arch, the more the planta fascia relax, because a higher arch shortens the distance between where plantar fascia connect to the calcaneus and to the second phalange of each toe.

The side lobe also encourages the foot to cushion itself. The lobe extends from the mid-foot medial wall and it makes the insole wider than could fit without bending or compressing into average-sized shoes. When the insole is forced into a shoe, this overwide wall compresses to fit into the shoe. The wall in turn compresses the fatty tissue of the sole of the foot, which act as an extra cushion and by volume support the arch. This mid-foot insole element supports the foot as it tightens the muscle structure, ligaments and tendons in the metatarsal area as you prepare to push into the next step.

The embodiments of the present invention prevent the need to oversupinate. Elite runners strike the foot on the toe; more precisely, on the metatarsals of the fifth toe. Many of these runners oversupinate when their arch is insufficiently supported.

SUMMARY

The embodiments of the present invention are directed to an insole that satisfies the needs set out in the Background section.

The embodiments of the present invention comprise a dynamic insole comprising an insole proximal end to be worn adjacent a wearer's leg, an insole distal end, an insole lower surface and insole thicknesses, and insole edges where the form-fitted insole upper surface and the insole lower surface meet, wherein the insole further comprises:

a form-fitted insole upper surface that is fitted to contours of a wearer's foot;

a first material having a hardness between 40 Shore A and 90 Shore A which enables the insole under a weight of a wearer's foot to deflect downwards from an original position and then return back to the original position;

insole thicknesses tapering down into the insole edges;

a medial arch support;

a deep heel cup;

a flat heel portion in the insole lower surface;

a medial upwardly-curved side wall and a lateral upwardly-curved side wall for cradling a foot;

a lobe for widening the insole, wherein the lobe extends from the medial upwardly-curved side wall;

a first windlass-shaped cutout at the insole distal end that reveals metatarsal heads I and II;

a second diagonal-shaped cutout for fourth and fifth toe phalanges that reveals metatarsal heads III, IV and V; and an insole distal end tongue between and formed by the first and second cutouts, the insole distal end tongue comprising a flat lower surface.

Optionally, the first material is dual-density ethylene-vinyl acetate foam.

Optionally, the first material has a Shore hardness value of 45.

Some Advantages of the Embodiments of the Invention

For any toe, the plantar band is shortened when the metatarsal head is allowed to drop and the arch is supported. Shortening the plantar band reduces strain to the plantar fascia. Shortening the plantar band also encourages supination as this facilitates arch support.

The deep heel cup distributes weight over a large area, which prevents the heel from rolling inward with pronation, which helps support inward and outward movement of the calcaneus as well as encourages as varis/valgus position when calcaneus is rested. In addition the deep heel cup creates a border which contains the soft tissue on the bottom of the heel in a prescribed area. The soft tissue comprises a cushion.

The form-fitted attribute maximizes insole contact with the bottom of the foot. This disperses and distributes energy, preventing pressure areas that lead to open blisters, ulcerations, loss of dermis, breakdown of fatty tissues used to cushion the foot, bruised metatarsals and unnatural foot placement. It also stops the fatty tissues from spreading and flattening out; flattening out would decrease their efficacy.

A material with a Shore durometer between 45-65 is compressible. A material with a Shore durometer between 75-90 is rigid and has substantial memory, e.g., if deflected downwards it remains flexed downwards. Shoe insoles are generally 10-20 durometers and they quickly lose their shape.

The insole medial side wall comprises a lobe at the medial arch. When a wearer inserts a foot into a shoe containing the insole, the foot is bedded on the medial side wall creating a downward pressure. The interior of the medial side of the shoe acts as a form that restricts the medial side of the insert, in particular the lobe, from spreading out and or flattening. Thus the medial side wall of the insert stays high and its arch support stays in place. This arrangement also has the effect of discouraging foot pronation, which is very important because supination is the natural and healthy foot method. The foot should strike when walking or running minus the small percentage of the population that may have a foot deformity.

These and other advantages will become apparent as the embodiments of the invention are used.

DRAWINGS

These and other features, aspects and advantages of the embodiments of the method will become better understood with reference to the following description, appended claim and accompanying drawings where:

FIG. 1 shows a top plan view of an embodiment of the invention, left foot insole;

FIG. 2 shows a bottom plan view of an embodiment of the invention, left foot insole;

FIG. 3 shows a front elevation view of an embodiment of the invention, left foot insole;

FIG. 4 shows a rear elevation view of an embodiment of the invention, left foot insole;

FIG. 5 shows a right side elevation view of an embodiment of the invention, left foot insole;

FIG. 6 shows a left side elevation view of an embodiment of the invention, left foot insole;

FIG. 7 shows a perspective view of an embodiment of the invention from the top, left foot insole; and

FIG. 8 shows how the insole flexes or deflects downwards from a first position and then returns back to the first position.

REFERENCE NUMERALS FOR DRAWINGS

• dynamic insole 10
• insole lower surface 15
• insole upper surface 20
• medial arch support 25
• deep heel cup 30
• medial upwardly-curved side walls 35
• lateral upwardly-curved side walls 40
• lobe 45
• flat heel portion 50
• insole proximal end 55
• insole distal end 60
• first windlass-shaped front cutout for great toe phalanges 65
• second diagonal-shaped front cutout for fourth and fifth toe phalanges 70
• insole distal end tongue 75
• insole distal end tongue flat lower surface 80

DESCRIPTION

Definitions

A form-fitting insole is an insole that tightly s the contours of the bottom and sides of the foot.

The toes are, from medial to lateral:

The first toe, also known as the hallux (“big toe” or “great toe”), the innermost toe;

The second toe, or “long toe”;

The third toe, or “middle toe”;

The fourth toe, or “ring toe”;

The fifth toe, “little toe”, “pinky toe”, or “baby toe”, the outermost toe.

The metatarsal bone can be divided into three parts; base, body and head. The base is the part closest to the ankle and the head is closest to the toe. The narrowed part in the middle is referred to as the body of the bone.

Metatarsal head I corresponds to the great toe and metatarsal head V corresponds to the little toe.

The American Society for Testing and Materials (ASTM) D2240 standard recognizes twelve different durometer scales. These scales are referred to as durometer types. A durometer type is specifically designed to determine a specific scale, and the scale does not exist separately from the durometer. The A scale is for softer plastics, while the D scale is for harder ones. However, the ASTM D2240-00 testing standard calls for a total of 12 scales, depending on the intended use; types A, B, C, D, DO, E, M, O, OO, OOO, OOO-S, and R. Each scale results in a value between 0 and 100, with higher values indicating a harder material. Thus a hardness value of 40 on the A scale is referred to as 40 Shore A.

Ethylene-vinyl acetate (EVA) is a co-polymer of ethylene (C₂H₄) and vinyl acetate (CH₃CO₂CHCH₂). EVA foam is almost as soft and flexible as many rubbers, but is easier to process and manipulate in manufacturing of different goods due to its thermoplastic properties.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE

As shown in the figures, the preferred embodiment and best mode of the present invention comprise a dynamic insole 10 comprising an insole proximal end 55 to be worn adjacent a wearer's leg, an insole distal end 60, an insole upper surface 20, an insole lower surface 15 and insole thicknesses, and insole edges where the form-fitted insole upper surface 20 and the insole lower surface 15 meet, wherein the insole further comprises:

a form-fitted insole upper surface 20 that is fitted to contours of a wearer's foot;

a first material having a hardness between 40 Shore A and 90 Shore A which enables the insole under a weight of a wearer's foot to deflect downwards from an original position and then return back to the original position;

insole thicknesses tapering down into the insole edges;

a medial arch support 25;

a deep heel cup 30;

a flat heel portion 50 in the insole lower surface 15;

a medial upwardly-curved side wall 35 and a lateral upwardly-curved side wall 40 for cradling a foot;

a lobe 45 for widening the insole, wherein the lobe 45 extends from the medial upwardly-curved side wall 35;

a first windlass-shaped cutout 65 at the insole distal end that reveals metatarsal heads I and II;

a second diagonal-shaped cutout 70 for fourth and fifth toe phalanges that reveals metatarsal heads III, IV and V; and

an insole distal end tongue 75 between and formed by the first and second cutouts, the insole distal end tongue comprising a flat lower surface 80.

Preferably, the first material is dual-density ethylene-vinyl acetate foam.

Preferably, the first material has a Shore hardness value of 45.

An insole having a Shore hardness value of 85-90 has the longest life. An insole having a Shore hardness value of 45 provides more cushion than higher values (46-90) but it breaks down faster.

The preferred material is foam EVA. Gel in contrast keeps its thickness but when it wears out it becomes less dense because the molecules disperse.

Some advantages of the embodiments of the apparatus were previously enumerated in the Summary section. Every advantageous feature does not need to be incorporated into every embodiment of the apparatus and/or methods.

Although these versions of the invention have been described in considerable detail, other versions are possible. For example, embodiments can comprise combinations of the features described herein, such as combinations of the dependent claims. Therefore, the spirit and scope of the appended claims should not be limited to the description of the versions contained therein.

Claims

1. A dynamic insole comprising an insole proximal end to be worn adjacent a wearer's leg, an insole distal end, an insole upper surface, an insole lower surface and insole thicknesses, and insole edges where the form-fitted insole upper surface and the insole lower surface meet, wherein the insole further comprises:

a form-fitted insole upper surface that is fitted to contours of a wearer's foot;

a first material having a hardness between 40 Shore A and 90 Shore A which enables the insole under a weight of a wearer's foot to deflect downwards from an original position and then return back to the original position;

insole thicknesses tapering down into the insole edges;

a medial arch support;

a deep heel cup;

a flat heel portion in the insole lower surface;

a medial upwardly-curved side wall and a lateral upwardly-curved side wall for cradling a foot;

a lobe for widening the insole, wherein the lobe extends from the medial upwardly-curved side wall;

a first windlass-shaped cutout at the insole distal end that reveals metatarsal heads I and II;

a second diagonal-shaped cutout for fourth and fifth toe phalanges that reveals metatarsal heads III, IV and V; and

an insole distal end tongue between and formed by the first and second cutouts, the insole distal end tongue comprising a flat lower surface.

2. The insole of claim 1, wherein the first material is dual-density ethylene-vinyl acetate foam.

3. The insole of claim 1, wherein the first material has a hardness value of 45 Shore A.