US 3257742 A
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Description (OCR text may contain errors)
June 28, 1966 R. s. FEINBERG FOOT SUPPORT FOR SHOES Filed Feb. 8,
INVENTOR ROBERT 5. FE I NBERG NW A. PW
ATTORNEY United States Patent 3,257,742 FOOT SUPPORT FOR SHOES Robert S. Feinberg, 81 Edgemont Place, Teaneck Township, Bergen County, NJ. Filed Feb. 8, 19.63, Ser. No. 257,817 5 Claims. (Cl. 36-44) My invention relates to shoes generally and specifically to a soft, readily deformable foot support adapted for mounting inside of a shoe between the foot and the insole having a plastic or putty-like consistency which is readily impressionable in response to pressure exerted thereon by the foot but which also has the quality of elasticity wherein there is a shape-recovery after the pressure exerted thereon has been removed and is a continuation-in-part of my US. patent application, Serial Number 175,564, filed February 26, 1962, now abandoned.
Ideally, a foot support should be soft and readily deformable to accept the impression of the sole of the foot. In this manner, the weight of the body is evenly distributed over a relatively large area rather than being concentrated at a relatively few points of contact. Both the soft fabric support and the sponge rubber support tend to crush at points of extreme pressure to present a hard unyielding surface. Neither of these materials deform to evenly distribute the pressure about a relatively large area defined by the entire sole of the foot. In order to overcome this defect, well-known, molded insoles have been developed. These insoles are fabricated by recording the impression of the foot in a plasticlike substance while the weight of the body is supported thereon. Thereafter, the plastic-like substance is hardened to present a shaped but unyielding insole or separate foot support.
A foot support having a permanent impression of the sole of the foot will tend to distribute the weight of the body evenly over a relatively large area. However, the shape of the impression made by the foot changes continuously as the weight distribution thereon changes. Thus, depending upon the use to which the foot is being placed, new pressure points continuously develop in response to the changing shape of the foot. A foot support having a fixed, unyielding impression cannot accommodate to these changes resulting in inflamed and extremely painful pressure points,
Therefore, it is among the objects and advantages of my invention to provide a foot support for shoes having a soft, readily deformable, putty-like consistency which is adapted to accept the changing impressions made by the foot thereby distributing the weight of the body evenly over a relatively large area.
Another object of my invention is to provide a foot support for shoes having a soft, readily deformable, putty-like consistency which is sufficiently elastic to recover its original shape and form after pressure exerted thereon is removed.
A further object of my invention is to provide a foot support for shoes that cannot crush under the weight of the body to present a hard, unyielding surface, but, will at all times and at all points on the sole of the foot, present a soft, pliable readily deformable and impressionable surface which will mold itself around the bottom of the foot.
Still a further object of my invention is to provide a foot support for shoes in which the physical characteristics relating to the pliability, deformability and impressionability may be varied to accommodate persons of different weight, the style of the shoe and the use to which the shoe is to be put.
Yet another object of my invention is to provide a foot support for shoes which will readily absorb and "ice ventilate perspiration maintaining a healthy, dry condition as intended by nature.
Still a further object of my invention is to provide a foot support for shoes which can be molded and cured to receive a permanent impression of the bottom of the foot but which is sufficiently deformable thereafter to adjust to specific changes in the shape of the sole of the foot which deforms while walking or standing and which is nevertheless sufficiently elastic to return to the initial or original impression when the pressure exerted thereon is removed.
These objects and advantages as well as other objects and advantages may be achieved by my invention one embodiment of which is illustrated in the drawings in which:
FIGURE 1 is a view in perspective of my foot support for shoes;
FIGURE. 2 is a cross-sectional view of my foot support shown in FIGURE 1.
My invention may take any one of a number of forms. Fundamentally, the invention comprises a pad or mat of a substance having a soft, pliable, readily deformable, plastic putty-like consistency adapted to receive the impression of the bottom of the foot when weight is placed thereon but which also exhibits the characteristic of shape recovery when the pressure is removed. The mat or pad may be covered on its top with a layer of 'soft felt having no sizing or starch. Either the top or the bottom or both the top and bottom of the'pad may be provided with a very thin piece of polyurethane foam, sponge rubber, foam rubber or a large number of other natural or synthetic materials which exhibit a cushioning effect. Polyurethanes are particularly useful when employed on the top of the pad since they both cushion the foot and breathe to release perspiration. However, it should be noted that this underlying or overlying cushion does not effect the action of the mat itself and may be dispensed with altogether. The entire assembly is then encased in very high quality leather containing no dye or other harmful chemicals or paper with fibre, plastic or some other suitable material. While I have shown the pad to be encased, no casing is necessary when the material from which the pad is formed will not slowly flow outwardly between the lining and the side of the shoe to engage the foot.
This basic configuration may be employed as an integral or detachable foot support for shoes or as an arch support and may be provided with varying degrees of hardness as well as varying rates of both deformation and shape recovery. In addition, the pad or mat may be invested with a permanent but yielding impression of the foot. In such cases, the pad will deform in accordance with changes in the shape of the bottom of the foot when changing stresses are exerted thereon and will always return to the original impression when the stresses are removed. Such a foot support would be applied only to a custom made shoe or a shoe the support for which was custom made.
For convenience, I have shown in the drawings a foot support for shoes which is not initially invested with a shape or impression of the bottom of the foot, but which is rather fiat on both the top and bottom when not in use. Referring now to the drawings in detail, my foot support comprises a pad or mat 11 which is covered on the top with a piece of soft felt 12 having no sizing or starch of any kind. The bottom of the pad 11 is covered with a thin piece of polyurethane foam 13. As noted above, the top of the mat 11 could also beprovided with a thin piece of polyurethane foam. The pad 11, the felt 12 and the polyurethane foam 13 are encased within a leather cover 14 which closelyconforms to the contour of the mat 11. Of course, the peripheral configuration of the mat 11 may be made initially to conform to the shape of the inner sole of the shoe into which it is to be placed.
Although I have shown only one type of foot support, it should be remembered that my invention may be practiced in many forms. For instance, a positive cast of the impression of the entire sole of the foot may be made in plaster and then dipped into the uncured substance from which the pad is fabricated. As this substance cures, the impression of the sole will be permanently recorded.
Generally, the same procedure may be employed to make the cast of the arch of the foot encasing it in felt and leather and placing it within the shoe to support the arch. An orthopedic commercial arch support may be made by placing a large mass of Durhams water putty or some similar material covered with saran wrap to prevent sticking on a board and causing the wearer to place the weight of his foot thereon so that the putty engages the underside of the arch. A negative cast of the arch is made in plaster from the positive cast of putty. The uncured substance from which the mat is made is then poured into the plaster negative cast and cured therein to produce a positive cast of the arch which is then encased in felt and leather.
In commercial applications, the support may extend only in certain limited areas of the shoe to accommodate for style and shoe construction. mat may be placed either on top of the insole or between the insole and the outsole. Of course, when placed on top of the insole, a sock lining is mounted on top of the mat.
A plain commercial arch may be provided which is shaped and dimensioned to a plurality of average sizes for both men and women. While these arches would not bear the precise image of the wearers arch, it will quickly deform to accommodate the pecularities of the arch of the foot bearing upon it to provide essentially the same support and comfort found in the orthopediccommercial arches.
In each instance, the particular characteristic of the arch support or foot support is dependent upon the material from which the pad or mat is formed. A number of substances have been found which satisfy the necessary characteristics. For instance, a number of epoxy resins when properly cured have been found satisfactory. In addition, polymerized butadienes having various specific molecular configurations may be employed successfully. In addition, some urethanes exhibit the desired characteristics.
Whether using various epoxy resins or the butadienes, the resulting mat or pad when cured has a soft, pliable, readily deformable, putty-like consistency which will readily accept the impression of the bottom of the foot when weight is placed thereon but which is also sufliciently slowly elastic to return to its original shape when pressure is removed.
Although the recovery of the mat is for all practical purposes complete, the imprint of the foot remains some what visible in the leather-felt casing because the easing tends to trap some of the material into the shape into which it has been pressed. However, there is no permanency to this impression and no resistance to the formation of any number of different impressions. This is commercially important since a number of persons may try on the same shoe for fit and appearance without permanently deforming or otherwise impairing the foot support. In addition, the material from which the pad is formed will not flow under pressure. The peripheral shape and size remains substantially the same. This characteristic I call dimensional stability.
Referring now to epoxy resins, the resin is a viscous flowable substance when uncured which will take the shape of the container into which it is poured. When resins of this type cure, a solid mass is produced which In addition, the
has the shape of the container and which permanently retains this shape without distortion so long as no pressure is exerted thereon. However, if pressure is exerted thereon, the cured resin has a yielding, readily deformable consistency which will adjust to the impression of the sole of the foot. After the weight of the foot has been removed, the cured resin demonstrates the quality of almost perfect elasticity, returning to its original shape in a rather slow manner. The speed of both deformation and shape recovery may be controlled precisely over a wide range according to the specific needs.
I have developed a number of formulas employing various epoxy resins which when cured exhibit the desired characteristics. One such epoxy resin having an epoxy equivalent of 0.51 and a viscosity of 20,000 centipoise at 23 C. and a specific gravity of 1.17 at 23 C./23 C. Chemically, it comprises an unmodified bisphenol-a epichlorohydrin monomer represented by the following structural formula:
This resin is commercially available from Ciba Products Corporation of Fairlawn, New Jersey, and sold presently as Araldite 6010.
Another suitable epoxy resin is a liquid epoxy resin having an epoxy equivalent of 0.26, a viscosity of 35,000 centipoise at 25 C. and a specific gravity of 1.13 at 25 C./25 C. This epoxy is produced by the reaction of glycol and epichlorohydrin and may be represented by the following general structural formula:
Where R R R and R may be hydrogen or an aliphatic chain. R may be (CH where n is at least one. This epoxy is commercially sold by the Ciba Products Corporation, aforementioned, under the trade name of Araldite DP437.
A third epoxy resin which has been found suitable is similar to the first mentioned resin, Araldite 6010, but is modified with dibutylphthalate. This resin is sold commercially as Araldite 502 by the said Ciba Products Corporation or as Epotuf 6131 by the Reichhold Chemical Company.
Various hardeners have been found suitable; one such hardener is a liquid having a viscosity of 27 centipoise at 25 C., and a specific gravity of 1.01 at 25 C./25 C. It is a synergistic combination of various aliphatic polyamines which may be represented by the following structural formula:
ucts Corporation aforesaid. Another class of suitable hardeners are the polyamide amines. One such polyamide amine has an amine value of 290 to 320, a specific gravity of 0.97 and a viscosity of approximately 500 poise at 23 C., and is commercially sold as Versamid 125 by the General Mills Corporation of Kankakee, Illinors.
A large number of epoxy resins may be employed in my invention. For instance, there are other bisphenol-a epichlorohydrin resin systems modified by hydroxyl groups represented by the following formulas which are suitable for my purposes:
Bisphenola Epiehlorohydrin Another suitable hardener is a modified polyamid of the general structural formula:
While the epoxy resins exhibit desired characteristics when properly cured, linear polybutadienes also exhibit these characteristics. A characteristic bu-tadiene comprises 35 percent of the cis 1,4 configuration, 57 percent of the trans 1,4 configuration and .8 percent of the vinyl 1,2 configuration; The remaining portion of the polymer product comprises stabilizers and a small amount of ash residue from the catalyst. There are an enormous number of specific butadienes having the same general characteristics but having specifically different molecular weights and. configurations as well as hardness depending upon the amount of hardener employed and the specific conditions of reaction. All of these products exhibit generally the characteristics desirable in my invention and their hardness and rate of deformation and shape recovery may be carefully controlled as may the hardness and rate of deformation and shape recovery of the epoxy resins. cured resins and the time and temperature of curing will determine the final specific characteristics of the polymer.
A number of formulations comprising the aforementioned constituents have been tested and found effective. One such formulation characteristic of those which produce a cured epoxy resin having the desired properties is:
Component: Parts by 'weight Araldite 6010 15 Araldite DP437 85 Araldite DP125 8.5
The components are mixed and placed into the mold and baked in an oven for approximately two hours at approximately 275-300 F.
The same formula can be further hardened by increasing the baking time up to approximately to 12 hours total baking time to produce suitable cured resins of increasing hardness.
These same constituents can also be employed to produce a cured resin having decreased hardness with the same curing time and temperature by the following formula:
Component: Parts by weight Araldite DP437 93 Araldite 6010 7 Araldite DP125 8.5
A very soft resin will be produced by the following formula when cured for the same time at the same temperature as the first formula:
Component: Parts by weight Araldite DP437 98 Araldite DP125 8.5
Araldite 6010 2 Such parameters as the ratio of hardener to un- A cured resin having average characteristics also may be produced by the following formula:
Component: Parts by weight Versamid 125 0.15 Araldite 502 1.0
The components are mixed and placed in the mold and cured for approximately two hours at approximately 200 to 250 F.
A harder than average cured resin may be produced by the same components cured for the same time and at the same temperature employing the following formula:
Component: Parts by weight I Versamid 125 0.18 Araldite 502 1.0
A softer than average cured resin may be produced by the same components cured for the same time and at the same temperature employing the following formula:
Versamid 125 0.13 Araldite 502 1.0
As in the case of the first mentioned components, or formula employing Versamid 125 and Araldite 502, this formula may be made increasingly more hard by increasing the time of curing.
It should be borne in mind that a so-called average hardness is diflicult to define since it is based largely on personal desire and market acceptability. However, when employing an epoxy formula using Cibas Araldite products, the Araldite DP437 and Araldite 6010 should add up to 100 parts by weight; the Araldite DP125 should remain approximately 8.5 to 11 par-ts by weight. The greater the concentration of Araldite 6010, the harder the product and vice versa. Curing temperatures range from 200 F. to 300 F. or even higher, for periods of approximately 2 hours. As a general rule, the longer the curing time the harder the product to a limit. Also as a general rule, the higher the temperature of curing, the harder the product and vice versa to a limit.
In the Versamid resin system, the more Versamid 125 employed the harder the product. In addition, the longer the curing time, the harder the product. The Versamids are cured at approximately 200 F. to 225 F. for 21 period of approximately two hours.
In the Araldite system, the Araldite may be employed in a range of from 2 to 40 parts Araldite 6010 with the Araldite DP437 making the total 100 parts by weight, the Araldite DP125 remaining essentially constant at 8.5 parts by 'weight. The Versamid system employs a Versamid 125 range from 0.13 to 0.3, the Araldite 502 remaining constant at 1.0.
Many other formulas may be devised which employ either the epoxy resins or the polybutadienes aforementioned which will be suitable. For instance, one such suitable epoxy resin is a bisphenol-a epichlorohydrin resin system modified by hydroxyl groups presently being manufactured by the Marblette Corporation of Long Island City, New York, and identified as Maraset Resins Nos. 636, 63 6a, or 638. These resins may be cured by a modified polyamide of the general formula set forth above to produce polymers having the desired characteristics. For instance, the Maraset Resin 638 may be polymerized with the modified polyamide hardener in ratios of to parts by weight resin to 100 to 150 parts by weight hardener. When employing Maraset Resin 638, the more hardener employed, the softer the products. In ratios of approximately 100 parts of Maraset Resin 638 to parts of hardener, no real deep impression of the foot may be observed. However, the material will eventually deform to the general contour of the foot providing a rather smooth surface upon which to walk. By employing a ratio of 100 parts of Maraset Resin 638 to parts of hardener, a polymer which is softer and will deform to the exact contour of the wearers foot rather rapidly and Parts by weight will recover more slowly is produced. Marblette Corp. also manufactures an unmodified bisphenol-a epichlorohydrin as Maraset 636B which when properly cured produces an acceptable product.
The polybutadienes should .be provided with any wellknown, no flow additive to render them more viscous. The product obtained is commercially acceptable, will not flow under heat and pressure, is not sticky, and will not soak through or squeeze through scams or stitch holes.
When the foot support is placed in the shoe, the foot will sink into the soft pad providing the-type Otf support found in nature when walking on soft sod or sand. The various bones of the foot which are supporting the greatest portion of the weight are permitted to extend downwardly to their extreme limit of movement without engaging an unyielding surface which would naturally distort the foot and cause pain from both dislocation of bones and ligaments and excessive pressure exerted against soft tissue. As the foot moves during walking, the forces tending to distort its shape also change. My pad will change in accordance with the demands of the foot providing complete support at all times. New pockets will be quickly dug out to accommodate changing bone positions due to changing weight demands imposed thereon. When the weight is removed, the mat, which is elastic,
quickly returns to its original shape to provide complete support should it be again demanded. No permanent wells or deformations are made in the pad as in the case of the common, preformed foot support. Unlike a rubber pad, the pressure exerted by the foot never compresses my mat to a thin, hard, unyielding surface without support to adjoining regions. To the contrary, the mat provides a cushioning support at all times over large areas as it continually deforms to accommodate the changing impression of the foot. In some instances, it may be desirable to impress an image of the foot into the mat as it cures, thereby permanently retaining a base or neutral impression for the foot. However, even this impression will yield and deform to accommodate changes in the shape of the foot while walking only to return to its original form and shape after pressure is removed.
The foregoing description is merely intended to illustr-ate an embodiment of the invention. The component parts have been shown and described. They each may have substitutes which may perform a substantially similar function; such substitutes may be known as proper substitutes for the said components and may have actually been known or invented before the present invention; these substitutes are contemplated as being within the scope of the appended claims, although they are not specifically catalogued herein.
1. A foot support for shoes comprising a mat of material having a soft, pliable, readily deformable and impressionable consistency under pressure exerted by the foot shaped for positioning over at least a portion of the weight bearing areas in a shoe and capable of retaining an impression of at least a portion of a foot after pressure has been removed, and thereafter recovering its original shape, said material being selected from the group consisting of cured polymerized epoxy resin and a cured linear polybutadiene.
2. A-foot support for shoes in accordance with claim 1, a pliable sheet on top of the mat conforming generally in shape with the bottom of a foot, and a soft cushion on the bottom of the mat.
3. A foot support in accordance with claim 2 and a cover enclosing the mat formed of material relatively impenetrable to the substance of the mat.
4. A foot support for shoes comprising a mat in accordance with claim 1, wherein the mat is fabricated from material selected from the group consisting of polymerized epoxy resin cured with a suitable hardener, and a linear polybutadiene.
5. A foot support comprising a mat in accordance with claim 1, wherein the mat is fabricated from a material chosen from the group consisting of polymerized epoxy resin cured with an amine hardener and a linear polybutadiene in which the ratio of the apoxy resin to amine hardener in the case of the epoxy resin mat lies within the range of approximately :20 and wherein the epoxy resin and hardener are cured from approximately 2 hours to 12 hours at approximately 200 F. to 225 F.
References Cited by the Examiner UNITED STATES PATENTS 89,105 4/1869 Williams 36-44 2,546,827 3/1951 Lavinthal l28595 2,684,541 7/1954 Hirschl 128594 2,742,657 4/1956 Sloane 12-l46 2,760,281 8/1956 Cosin l28595 FRANK J. COHEN, Primary Examiner.