Stock material or miscellaneous articles – Sheet including cover or casing – Foamed or expanded material encased
Patent
1997-11-17
1999-09-28
Copenheaver, Blaine
Stock material or miscellaneous articles
Sheet including cover or casing
Foamed or expanded material encased
36 43, 36 44, 36 93, 36154, 36DIG2, 264316, 26433111, 4283044, A43B 714
Patent
active
059585463
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to insoles generally and more particularly to custom insoles which are directly molded by pressure from a user's foot.
Various types of custom insoles are known in the patent literature. It is particularly known to form insoles by pressing a foot of a user on a material which eventually hardens to a conformal shape of the foot.
There are several examples of forming such custom insoles with a two-part curing system. One example is described in U.S. Pat. No. 4,128,951 to Tansill, in which the insole is formed by a two-part elastomeric material. A curable liquid elastomeric material is cured by breaking a compartment which contains a catalyst which mixes with the liquid and cures it to the conformal shape of a foot of a user. A problem of this patent is that it uses a premeasured quantity of curable material and catalyst which may be too much or too little for a particular user, thereby forming inadequate insoles.
Tansill suggested a solution for this problem in U.S. Pat. No. 4,385,024 in which special equipment is used to measure the correct amount of material for a particular foot. However, this method is expensive and time consuming.
In a further patent, U.S. Pat. No. 4,272,898, Tansill describes a shoe insert made of a mass of fibers coated with a curable resin and other fibers which are hollow and contain a curing agent. The hollow fibers are rendered frangible such that the curing agent is uniformly released. However, it is difficult to make the insert structure such that the hollow fibers are uniformly dispersed among the coated fibers. The proposed method of rendering the hollow fibers frangible requires special equipment and treatments.
U.S. Pat. No. 5,095,570 describes making an insole with a material containing an uncured resin which is cured by injecting an activating agent into the resin. This patent suffers from the inconvenience of having to inject the activating agent which requires a special tool, and which does not guarantee that the activating agent will mix properly and uniformly with the resin.
There are other examples in the art of making the insole with a one part system. An example of making such an insole is described in U.S. Pat. No. 3,895,405. The method involves placing a flexible foam insole in a shoe, heating the insole to a temperature sufficient to cause the foam to lose some of its resiliency, placing the foot in the shoe before the insole regains its resiliency, and taking steps with the foot in the shoe until the insole regains its resiliency.
A disadvantage of the '405 patent is that it is difficult to obtain the requisite height of the insole merely by the molding process alone, and additional layers must be added to the insole with subsequent trimming.
In an article entitled "Shoe inserts for small deformed feet", by R. G. S. Platts, S. Knight and I. Jakins, Prosthetics and Orthotics International, 1982, Vol. 6, pp. 108-110, a method is described for molding inserts inside the shoe. The method uses a liquid polyurethane foam which has a curing substance pre-mixed with the foam. The foam is poured into a mold in the shoe and quickly hardens to form the insole. However, the method is rather messy, laborious and time-consuming. Uncontrolled pressure created in the shoe during molding may cause a change in foot shape and placement with respect to the shoe.
Thus, there is a need for a one-part system for creating a custom-insole which cures fast, is not messy nor laborious, and which reliably and faithfully reproduces the shape of the user's foot.
The present invention seeks to provide an improved insole precursor which is solid and stable and may be stored indefinitely before being transformed into a custom insole by pressing thereon with a foot of a user. There is no need for adding any activating agent or catalyst. The insole precursor may be placed in a shoe and the user may walk with the shoes for a few hours while the precursor permanently deforms into the custom insole. There is no need for pre-heating the precursor.
Since the precursor onl
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patent: 5203793 (1993-04-01), Lyden
Makover Yaacov
Mardix Bar-Cochva
Sadeh Yaacov
Copenheaver Blaine
Friedman Mark M.
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