Removable Arch Support

In the drawing:

FIG. 1 is a perspective view of a presently preferred embodiment of the arch support device showing its positioning under the instep of a left foot (with the shoe and sock not shown for clarity);

FIG. 2 is a bottom plan view of the device of FIG. 1;

FIG. 3 is a side view of the left foot device of FIG. 1 taken along the line 3--3 in FIG. 2;

FIG. 4 is a longitudinal sectional view taken along the line 4--4 in FIG. 2;

FIG. 5 is a front view of the left foot device of FIG. 1 taken along the line 5--5 in FIG. 2; and

FIG. 6 is a transverse sectional view taken along the line 6--6 in FIG. 2.

Generally speaking, as shown in the drawings, the invention provides a relatively small unitary member 10 which is sized and shaped for removable use inside a conventional shoe without the need for any fastening devices. Of course, where it is deemed necessary in a particular case, a person may nevertheless use a fastener such as adhesive, Velcro or the like, but that is not essential to the invention in its basic form. As best shown in FIG. 1, the length of the member 10 is shortened at both ends to leave the ball portion 12 of the foot as well as the heel portion 14 free and unencumbered without any portion of the arch support device interposed between the plantar surface and the shoe insole except in the area under the instep. In other words, the forward end is truncated so as not to extend beyond a location immediately posterior to the first and fifth metatarsals, and the rearward end is truncated so as not to extend beyond a location immediately anterior to the plantar prominence of the calcaneus.

A central arch portion 16 extends upwardly in order to form a resting bridge in the longitudinal direction as well as a resting bridge in the transverse direction. In reality the central arch portion is a continuous span which is supported in cantilever fashion from a front support base 18, a back support base 20 and a side support base 22, and the medial boundary of the central arch portion is preferably extended to project outwardly in an arc beyond the furthermost portions of the front and back support bases, which projection is designated 24. The aforesaid support bases are located adjacent to the periphery of the device (except there is no support base adjacent to the periphery at 24 along the medial boundary) and provide a stable foundation. The exact shape and dimensions of the central arch may be modified for each person (and for each foot of each person) to provide a custom-fitted arch support device which fairly closely matches the conformation of the plantar section of the instep. In fact, in many instances the arch support device (or foot orthosis as it is often called) is made pursuant to a prescription from a medical doctor, such as an orthopedist, and may be shaped to change or correct the shape of the plantar portion of the foot as formed into a casting by the person making the orthosis. Nevertheless, after much experimentation and changes based on careful monitoring of persons who were wearing orthotic devices in accordance with the inventors' specifications, a number of common features began to emerge as being necessary to provide comfortable, non-aggrevating support in different shoes over extended periods fo time and under a variety of different situations (running, jumping, hiking, prolonged walking, and the like).

One of the features of the present invention is the relatively thin vertical dimension of material throughout the entire device. It was found that in some instances the thickness throughout the entire member 10 could be substantially constant at about 0.06 inches. Any thickness less than that in the materials used for this embodiment created problems of insufficient rigidity and strength.

The perimeter line serves to provide a maximum contact surface for the three support bases 18,20,22 to transmit and dissipate the compression force applied downwardly against the central arch protion 16. In this regard, and more specifically as best shown in FIG. 2, a front edge 30 is preferably shaped to flare forwardly in the direction of the medial side of the plantar; a rear edge 32 is preferably shaped to flare rearwardly in the direction of the medial side of the plantar; and a lateral edge 34 is preferably shaped to arc slightly inwardly. The corners 36 were rounded off to provide added comfort to the person wearing the arch support device.

As a result of the foregoing considerations, the preferred embodiment of the present invention usually has a linear dimension in the longitudinal direction of approximately 41/2 inches or less as shown in FIG. 2 at A, and a linear dimension in the transverse direction of approximately 3 inches or less as show at B.

For most persons, and especially those wearing the orthosis who were unusually heavy or else especially inactive, it was found necessary and desirable to provide reinforcement in the medial side of the central arch support portion. Thus, in many instances the thickness was increased to as much as twice the thickness as the rest of the unitary member so that the thicker portion was 0.125 inches thick and the thinner portion was 0.06 inches thick. The added strength was therefore acquired without increasing the overall surface area of the plantar portion directly engaged by the upper surface 46 of the central arch and its support bases 18, 20, 22. Of course, it is to be understood that dimensions given are approximate only and might vary based on the material used to make and shape the unitary member.

In the preferred embodiment, the unitary member is a laminate formed by from three to seven plies of fiberglass impregnated with polyester resin of the thermosetting type. It was found that the combination of a fibrous material with a resin provided the necessary strength and rigidity, while at the same time providing the optional advantage of an appreciable amount of flexure or "give" in order to achieve some pronation. For further comfort, an optional feature is the use of sponge sheeting covering part or all of the top surface and particularly the edge of the support bases. Recent experimentation indicates that only one interply coat of resin may be required, thereby allowing closer packing together of multiple layers of the fiberglass material.

Of course, an epoxy could be substituted for the polyester resin, and initial experimentation with some thermoplastic material shows promise, thereby achieving the preferred shape and strength of the invention without having to laboriously build up a laminate with a plurality of layers of material. However, epoxy is rather slow to gel and might also cause skin rash for some people.

Additional strength against compressional stress was found by making the central arch portion in the shape of a compound curve, i.e., having the surface curve in two or more directions simultaneously. After extensive experimentation it was determined the preferable curvature for achieving this so-called compound curve was having transverse arm components present a concave surface to the plantar portion of the instep, as shown by arrows 44, and longitudinal arm components present a convex surface to the plantar portion of the instep, as shown by arrows 42. This still enabled a top surface 46 to remain in general supporting engagement against the plantar surface without localizing any compressional pressure on a particular section of the instep. Also, this did not interfere with the objective of cantilevering the central arch portion so that the underside surface 40 spanned any crowned arch support built into the shoe.

Since the stabilizing and positioning of a truncated arch support does not occur in most instances by separate fasteners attached to the arch support device, it is an important feature of the invention to extend the side support base 22 to the full breadth of the plantar surface at the midfoot area so that it is interposed between the loadbearing portion of the midfoot (located between the heel and ball of the foot) and the underlying shoe insole. Thus, the thin edges of the unitary member and the contouring as previously described helps to avoid discomfort around the peripheral portions of the device.

What has been shown and described is the preferred version or variously sized and shaped arch support devices which all have certain characteristics found to be necessary to achieve the objectives of the invention, and which were built to be easily inserted into existing shoes with little or no adjustment needed. In that regard, while it is believed that the actual shape of the perimeter of the arch support can be varied, the optimum perimeter design based on present information is the one shown and described, with the linear dimension D along the medial border greater than the linear dimension C along the lateral border.

Based on careful monitoring of experimental versions of the device used by orthopedic patients having various and sundry foot maladies, it was found that the improved arch support could be worn over prolonged periods of time without discomfort, and without injury or damage to either the person wearing the arch support or to the unitary customized support itself. This new orthotic device has proved effective in relieving patients of their symptoms of flatfootedness and hyperpronation. Patients who have had extensive experience with the conventional long orthotic have states that the short thin design of the invention was significantly more comfortable and relief of the symptoms was equal to or better than with the conventional design.

It will be appreciated that various changes, modifications, and substitutions could be adopted in the illustrated embodiment described and shown without departing from the scope of the present invention as set forth in the claims below. In that regard, applicants are continuing to experiment with refinements in the structure, shape and materials used in the orthotics of the present invention, including the use of fiberglass cloth layed down on the bias, specifically different types of polyester resins, and thermoplastic and thermosetting materials which would hopefully be formed in a single step (rather than the sequential laminating steps currently be used) into the uniquely sized and shaped unitary member of the invention which in its simplified way provides more advantages over periods of long use than has heretofore been possible.