US 2330398 A
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Description (OCR text may contain errors)
Sept. 28, 1943. s v ss 2,330,398
ARCH SUPPORT Filed Deb. 10, 1941 eorram COVER INL/ENTOR STEPHEN l/HSS HTTORNEY Patented Sept. 28, 1943 UNITED STATES PATENT OFFICE ARCH SUPPORT Stephen Vass, New York, N. Y.
Application December 10, 1941, Serial No. 422,353
The present invention relates to arch supports Wise incorporated in shoes to support the arch of the wearer's foot, or to correct certain pathologic conditions of the foot, and to a process for producing the same.
The weakening or breaking down of the arches of the foot has been a condition which has brought physical suffering to many people. The correction or cure of such a condition has been the problem of orthopedists for many years and from time to time numerous attempts have been made to solve this problem. Fundamentally, most of these attempts involved correction of the displacement of the bones of the foot and support of the arches thereof by means of a supporting member inserted in the shoe of the sufferer, or built into the shoe as an integral part thereof.
The earliest forms of arch supports employed for the purpose of correcting arch displacements and providing support for weakened arches essentially comprised a member of leather riveted or otherwise secured to a steel plate, more or less conforming to the contours of the ideal arch of the foot. In order to effectively sustain the body weight, the steel reinforcing plate had to be of considerable thickness and strength. This made the support practically unyielding and resulted in considerable discomfort of the wearer. In addition, such steel arch supports added appreciable weight to the footwear and greatly increasedthe physical effort required for walking particularly for persons who found it necessary to be on their feet for extended periods of time. The great rigidity of supports of this type frequently resulted in breaking or cracking of the steel reinforcing member after a relatively short useful life. While these disadvantages were well known to those skilled in the art, the industry was practically at a dead end for several decades and even at the present time the bulk of arch supports made and used comprises such unsatisfactory, rigid, heavy and bulky steel supports.
With increasing development of the art of plastics, synthetic resins, and the like materials, numerous attempts were made to employ these new materials for the construction of arch supports. The principal attraction of these materials was their light weight and simplicity of manufacture by means of stamping, hot-pressing or molding processes. Early attempts in this direction involved casting, molding or otherwise forming solid supports from resinous materials.
Such supports, While having the advantage of lightness, suffered from the disadvantage of structural weakness. When the resinous support was suflicient to carry the weight of the wearer, it was completely rigid, its use was as uncomfortable and painful as that of the steel supports and also the support would break and become useless quite easily. On the other hand, a support of the described character, made of plasticized resinous material would spread and flatten out and failed to provide the support and corrective effect upon the arches of the foot. A long line of experiments in this general direction proved a complete failure although a practically endless number of plastic masses has been employed including various additions such as ground pork, paper pulp, and fibers which were incorporated into the support in the hope of providing reinforcement of the same.
A further suggestion for the provision of a light arch support involved fabric or other fibrous material carrying or incorporated with phenolic condensation cementing material, such as Bakelite and a number of layers of canvas or other woven or knit fabric was suggested to give the desired thickness at various parts of the insole. This material was cured or hardened by the application of heat and pressure into a permanently solid condition. It was expected that the incorporation of fabric into the "Bakelite lacquer would reinforce the finished support sufficiently to stand up under the efiect of body weight. While the performance of this type of supports was somewhat better than that of the unreinforced resinous type, their strength was far from being satisfactory. Experience with these reinforced supports has shown that they would flatten out and would be deformed and become practically useless after a relatively short time which may be only a few days for individuals of great body weight and not more than a few weeks even for individuals of relatively light weight.
From the foregoing considerations it is manifest that none of the suggestions and proposals for the provision of a light weight, permanent and resilient arch support were satisfactory and successful when carried into practice on an industrial scale.
I have discovered that the outstanding prob.- lem may be solved in a remarkably simple manner.
It is an object of the present invention to eliminate the disadvantages and inconveniences at present lnseparably connected with arch supports.
It is another object of the invention to provide an arch support of novel and improved character which combines light weight with great and permanent mechanical strength, without loosing resiliency.
It is a further object of the invention to provide a novel arch support in which a completely new reinforcing concept is incorporated whereby light-weight, resilient and permanently form-retaining arch supports may be obtained even for individuals having very great body weight.
Still another object of the invention is to provide a novel arch support in which a substantially non-stretching, greatly foraminous metallic member, such as a wire screen, or metal cloth, is so intimately bonded with a resinous body that resinous mass and foraminous member lose their individual entity as structural members but form a unitary body of altogether novel structural and strength properties.
The invention also contemplates a novel arch support which is extremely simple in its construction, satisfactory and permanently formretaining in use, and which may be readily manufactured and sold on a practical and commercial scale at a cost which favorably compares with that of prior supports.
Other and further objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawing, in which:
Fig. 1 illustrates a top elevational view, having parts broken away for clarity of illustration, of a preferred type of arch support, embodying the principles of the present invention;
Fig. 2 depicts a longitudinal sectional view, somewhat diagrammatic in character, taken on line 22 of Fig. 1;
Fig. 3 shows a transverse sectional view, also diagrammatic in character, taken on line 3-3 of Fig. 1;
Fig. 4 is a fragmentary sectional view of a portion of the novel arch support showing the arrangement of the various layers of reinforcing metal cloth and resinous material greatly exaggerated in thickness; and
Fig. 5 is a perspective view of a modified embodiment of the present invention in an arch supporting insole which also includes a transverse metatarsal bar and a bunion-corrective toeseparator member.
Broadly stated, according to the principles of my invention, I provide a high-strength, lightweight arch support comprising one or a plurality of flexible metallic members of a highly foraminous but substantially non-stretching character. I prefer to employ metal cloth or screen woven from substantially non-stretching Wire, such as phosphor-bronze. This metallic reinforcing member or members are embedded in or are intimately bonded with a resinous material so that all of the interspaces of the metallic member are filled out with the resinous material. In this manner a unitary body is formed in which there is no relative movement possible between the metal cloth and the resinous material. I have found that extremely important new and unexpected advantages follow from the aforesaid combination of resinous mass and non-stretchable, intimatelybonded foraminous metallic member.
Due to the fact that the metal reinforcing member or cloth is firmly and intimately bonded with the resinous body, or impregnating mate-- rial, relative displacement of the metal cloth with respect to the resinous body is completely prevented. As a result of this complete and permanent band, body and metal cloth will form a single and inseparable structural unit which will integrally respond to mechanical stresses. As the support includes a plurality of curved or arched surfaces, pressure acting perpendicularly thereon as a result of the body weight of the wearer will have a tendency to stretch the wire cloth, and this being substantially non-stretchable, will counteract excessive bending, flexing or flattening of the support. In other words, flexing stresses on the unitary support body will be converted into tensional stresses within the wire cloth which is capable of readily absorbing the same without stretching. On the other hand, a moderate resilient flexing of the support is not excluded so that my novel arch supports avoid the discomfort and even acute pain connected with the use of conventional steel supports, which .are almost completely rigid. It could be stated, although somewhat loosely, that the operation of my novel arch support is comparable to that of reinforced concrete in which the embedded metallic members provide strength in the directions in which the cementitious mass has but little, and vice versa. In order to obtain best results, I prefer to arrange the Wire screen in such relative position with respect to the support that the crossed individual wires, or strands of the metal cloth extend substantially parallel with the longitudinal and transverse axes of the support. This relative arrangement assures the maximum strength of the finished structure and is superior to that obtainable by arranging the screen wires at another angle with respect to said axes.
Those skilled in the art will readily appreciate that these new results and particularly the critically important cooperation between the resinous body and the metal cloth cannot be obtained by the conventional incorporation of fabric, such as strong canvas, with a resinous cementing or bonding agent. Any textile fabric is stretchable to a very great extent, both in its individual threads and as a unit. Thus, any kind of fabric completely lacks the indispensable quality of l non-yielding strength. Moreover, the bond between a plurality of layers of textile fabric and a resinous cementing agent is necessarily superficial, the continuity of the resinous layers being completely interrupted by alternating interposed layers of fabric. The result is a Stratified structure having but little strength and resistance against relative displacement of the several strata with respect to each other. When sub- Jected to mechanical stresses, particularly in the perpendicular direction, the fabric layers will tend to be displaced with respect to each other and the impregnating material thereby causing separation of the various strata and subsequent collapsing and flattening of the complete structure.
The support embodying the principles of the present invention is preferably fabricated by forming a base member of suitable material, such as sole leather trimmed down to appropriate thickness and shaped upon a wooden form or last to have contours complementary to those of the ideal arch of the human foot. In some cases it might be found desirable to perforate this base member at a number of points in order to provide for better ventilation. Upon the exposed surface of this base material or member is applied a layer comprising principally resinous material which may be in the form of a viscous mass obtained by the incorporation of a suitable solvent. A layer of metal cloth is now applied upon the layer of resinous material or binder, covering the entire surface thereof, care being taken that the interstices between the various strands of the wire cloth are completely filled out. Successive alternate layers of binder and of metallic woven material are now applied. Generally speaking, it is not necessary to .have the subsequent layers of metal cloth cover the complete surface of the support but each successive layer may be of a smaller area than the preceding one. In this manner, the number of reinforcing layers is adjusted in accordance with the expected stresses in the various regions, the maximum number of metal cloth layers being provided in the regions where the stress is the greatest. It is very essential that all of the spaces between the individual strands of wire and the layers of the metal cloth be completely filled out with the resinous mass so that said mass forms a substantially continuous body and the bond between wires and mass is intimate and inseparable. When a suflicient number of layers has been laid down, a covering layer, such as canvas, etc. may be cemented to the uppermost surface of the laminated product and the whole structure is pressed with a second last or die of suitable shape. The pressure employed in this final step is sufficient to press the plurality of layers into an integral body of great mechanical strength and at the same time having the desired amount of resiliency in use, the upper surface of which conforms to the complementary contours of the ideal foot surface, while the other surface conforms to some extent to the shoe in which the support is to be worn. After the pressing operation, the support is trimmed and ground to eliminate rough edges and protruding filaments of the metallic reinforcing cloth. The support may be finished by the application of suitable surfacing materials which may be, for example, calf skin for the top and chamois, and the like for the bottom surface. The character of the resinous mass employed determines whether any heat is to be used in the final pressing operation, the simultaneous application of heat and pressure being desirable when thermoplastic or thermosetting resins are employed, such as vinyl resins, chlorinated rubber compounds, rubber-containing materials both of natural and synthetic type, etc. all of Which may be considered to be within the purview of the present invention.
When in addition to correcting deformations and deformities of the foot arches, it is also desired to correct the unnatural displacement of toes, particularly of the big toe, it is desirable to provide the novel arch support with a toe-separator of a special character. Such displacement of the big toe is caused by abnormal shortening of the corresponding muscle and results in the enlargement and displacement of the joint thereof commonly known as bunions. Prior attempts to incorporate toe-separators into shoes failed because of the tendency of the foot to slide within the shoe thereby largely negativing the efflcacy of the toe-separator. In order to reduce to a minimum or to eliminate entirely this tendency of the foot to become displaced laterally in the shoe, the novel supporter when employed in combination with a toe-separator, is provided with a transverse metatarsal bar. As a result,
' that created by the toe-separator whereby the beneficial effect thereof may be fully operative,
as it will be explained more fully hereinafter.
Of course, this type of device requires wearing of a special stocking in which the big toe is separated from the other toes.
The invention will now be more fully described in connection with the drawing. Referring more particularly to Figs. 1 to 4 of the drawing, a preferred embodiment of the invention in an arch support is shown. Reference character I denotes a sheet-like base member, forming the bottom surface of the support, which may be constituted of strong canvas with or without some other covering material, such as, for example, chamois. Upon the base member are arranged spaced layers of metal cloth 2, 3, 4, 5, 6 and I of which a suitable plurality is employed. As it will be best observed in Fig. 1, these layers of metal cloth have different spacial extension. Thus, for example, one or two of the lowest layers 2 may cover the entire surface of the support while the successive layers of metal cloth have gradually decreasing areas so that the maximum number of layers is provided where the stresses are the greatest, and vice versa. In the example illustrated six layers of the'metal cloth are provided in the central region where the requirement for supporting strength is the greatest and the number of layers decreases toward the marginal portions. Of course, the particular arrangement of the layers is coordinated to the particular type of deformity which is to be remedied, to the size of the foot and to the body weight of the individual, as those skilled in the art will readily understand. The intervals between the strands of the metal cloth layers and between the layers themselves are completely filled out with a suitable resinous mass or binder 8 which forms the body of the novel support. As it has been pointed out in the foregoing, the relationship between the spacing of the strands of the individual layers of metal cloth and the layers proper is such that the integral character of the all-permeating resinous mass-8 is fully preserved and that any relative displacement between the layers of metal cloth and the resinous mass is positively prevented. In this manner, a body of altogether novel structural and strength properties is obtained in which the individual structural properties of the ele ments are inseparably blended into a unitary structure. If desired, the novel support may be provided with rubber supporting pads 9 and with a top covering layer In of calf skin, and the like in the conventional manner.
While various types of metal cloth may be incorporated in my novel arch support, such as wire cloth constituted of a copper-nickel alloy sold under the trade name Monel, stainless steel, and the like, I prefer to use a metal cloth woven from phosphor-bronze wire having about fourteen to about twenty-eight strands per inch in both directions. It has been found that phosphor-bronze metal cloth commonly employed as screening for windows as protection against insects is satisfactory for this purpose. Such material has about sixteen mesh to the inch. Those skilled in the art know that phosphor-bronze is quite resistant to corrosion and has a tensile strength in the hard condition of about 60,000
to about 130,000 pounds per square inch. Of
course, the thickness of the individual strands and the mesh of the metal cloth may be adjusted to the type of support contemplated. a lighter material being used for womens shoes and heavier material for men's shoes and for shoes of individuals of great bodyweight.
It may be pointed out that instead of metal cloth greatly foraminous metal sheet of a flexible and non-stretching character may be likewise employed with similar results, although it will be found that the performance will not be as satisfactory, due to the inferior structural strength of such material. The foraminous character may be obtained for example by punching closely spaced perforations in metal sheet of suitable thickness and material.
The binder which ultimately forms the resinous mass filling out the interstices of the layers of metal cloth is constituted, preferably, principally of Celluloid in the form of a viscous solution in a suitable solvent, such as acetone. It is likewise satisfactory to apply the Celluloid as a sheet and to hot press the various layers of material to provide the desired binding action. Other resins or resinous materials of suitable plasticity and strength may be employed, of which examples are various cellulose derivatives other than cellulose nitrate, vinyl resins, urea-formaldehyde resins, phenol-formaldehyde condensation products, rubber-like materials both of natural and synthetic ori gin, chlorinated rubber compounds, and the like. Obviously, the type of resinous material employed largely determines whether. it is applied in the form of a solution in a suitable solvent, in the form of sheets which are molded and bonded into an integral mass by the application of heat and pressure or of heat alone, or in the form of a powder which is molded under the effect of heat and pressure. Those skilled in the art of plastics have no difficulty in determining the type of resinous material to be used and the preferred treatment for integrally uniting .and combining the resinous material with the metal cloth. Those skilled in the art will have no difficulty in determining desirability of incorporating a plasticizer in the resinous material. Nor will those skilled in the art have any difficulty in selecting the proper plasticizer nor the amount thereof to be used.
In Fig. 3 the distribution of the metal cloth layers transverse of the support is shown. It will be readily observed that layer 2 of the metal cloth extends across the entire width of the support whereas successive layers 3, 4, 5, 6 and I extend across decreasing portions of the cross section thereof. In this way that portion of the support which is under the greatest pressure is provided with the greatest strength.
It is recognized by those skilled in the art that the pedal deformity commonly known as a bunion results from shortening of th muscle of the big toe which displaces inwardly the forward portion of the toe with an accompanying displacement of the joint of the toe. To correct this condition, it has been the practice in the prior art to insert so-called toe-separators between the deformed toe and the adjacent toe. Such prior separators have been either unattached to the shoe or attached to the inner sole of the shoe. In either instance, the prior art failed to provide means to oppose the natural tendency of the foot to displace as a unit laterally in the shoe, which largely negatived the beneficial effect of the toeseparator. The practice of providing transverse metatarsal bars or wedges on the outer surface of the shoe sole did not fully solve the outstanding problem because they tended to destroy the balance of the shoe and placed torsional stresses on the shoe in the region where it is particularly weak.
I have found that the foregoing disadvantages may be fully eliminated by employing a toe-separator built as a unit with an arch support and incorporating a transverse metatarsal bar in the bottom portion thereof, thereby raising the outer side of the foot. In this Way the tendency of the foot to slide outwardly is effectively opposed and the corrective function of the toe'separator is positively maintained. A device of this type is 11- lustrated by way of example in Fig. 5 in which reference character 20 generally denotes an arch support, preferably of the type described in the foregoing, although obviously other types could be employed. A toe-separator member 2| is secured to the forward portion of the support in the proper relative position with respect to the big toe. A wedge-shaped transverse metatarsal bar 22 is incorporated in the lower surface of the arch support 20 whereby the foot will be forced into the proper cooperative position with respect to the toe-separator. As the corrective effect of the novel toe-separator progresses, the separator may be gradually displaced inwardly by the orthopedic shoemaker by removing the separator and cementing or otherwise securing the same to the support in a different position. For this purpose, the top covering layer 23 of the support is provided with a V-shaped incision or slit 24 conforming to the outer perimeter of the base of toeseparator 2 I. From the foregoing description the operation of my improved bunion-correcting device will be readily understood by those skilled in the art.
Although the present invention has been described in connection with a few preferred embodiments thereof, variations and modifications may be resorted to by those skilled in the art without departing from the principles of the present invention. I consider all of these variations and modifications as within the true spirit and scope of the present invention as disclosed in the foregoing description and defined by the appended claim.
An orthopedic device comprising in combination a resinous body defined by arch supporting surfaces, at least one highly foraminous and readily flexible metallic reinforcing member embedded therein, a toe-separator mounted on the upper face of said resinous body, and a transverse metatarsal bar mounted on the lower face of said body, said metatarsal bar being so constructed and arranged as to oppose the tendency of the foot to displace as a unit laterally in the shoe and being adapted to maintain the foot in a position in which the corrective influence of the toe-separator remains effective.