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Publication numberUS3896516 A
Publication typeGrant
Publication dateJul 29, 1975
Filing dateMar 29, 1973
Priority dateMay 24, 1971
Publication numberUS 3896516 A, US 3896516A, US-A-3896516, US3896516 A, US3896516A
InventorsDen Benken Elisabeth Von
Original AssigneeDen Benken Elisabeth Von
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Shoe molded by induction heating
US 3896516 A
Abstract
The invention concerns a shoe whose bottom has a layer of thermoplastic material in it and which has embodied in its bottom electromagnetic energy-absorbing material which can be heated by alternating magnetic flux, thus activating the layer of thermoplastic material which then can be molded according to the contour of a human foot.
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Description  (OCR text may contain errors)

United States Patent; 11 1 Von Den Benken 1451 July 29,1975

SHOE MOLDED BY INDUCTION HEATING lnventor: Elisabeth Von Den Benken, 2212 Centre St., West Roxbury, Mass.

Filed: Mar. 29, 1973 Appl. No.: 346,428

Related US. Application Data Continuation of Ser. No. 146,312, May 24, 1971, which is a division of Ser; No. 883,952, Dec. 10, 1969, Pat. No. 3,641,688.

US. Cl 12/142 R Int. Cl A43d 9/00 Field of Search 36/25 R, 2.5 AL, 43;

[56] References Cited UNITED STATES PATENTS 3,221,353 12/1965 ,Greene l2/l42 R 3,493,986 2/1970 Erwin 12/142 R 3,521,385 7/1970 Dalebout 36/2.5 AL

Prim'ary Examiner-Patrick D. Lawson [57] ABSTRACT The invention concerns a'shoe whose bottom has a layer of thermoplastic material in it and which has embodied in its bottom electromagnetic energyabsorbing material which can be heated by alternating magnetic flux, thus activating the layer of thermoplastic material which then can be molded according to the contour of a human foot.

2 Claims, '3 Drawing Figures 1 SHOE MOLDED BY INDUCTION HEATING BACKGROUND OF THE INVENTION This is a continuing application of divisional application Ser. No.: 146,312, filed May 24, 1971; said 'divisional application is a division of application Ser. No.: 883,952, filed, Dec. 10,1969; now US. Pat. No.:

This invention relates to footwear of any kind, as boots, sandals, shoes, etc... However, henceforth the word shoe will be used only. Human feet vary in length,

width and contour. There is even a difference between theleft and the right foot of the same person, due to gait and walking habits. In a shoe factory, the shoes are made over lasts which are to represent human feet. These lasts take into consideration the various lengths and widths, but as to the contour of a foot, they are a compromise only.

In the past, when shoes were hand-made and leather was the only material used, they could be fitted to the overall contour of each individual foot. Moreover, a leather shoe has the outstanding feature of gradually shaping itself to the contour of a human foot. The advantages of hand-made leather shoes have been lost to a great extent in present-day mass production. In particular, leather is replaced by synthetic material which .does not possess the feature of shaping itself to the contour of a human foot. For this reason, it is hard to break in new shoes made of synthetic material.

SUMMARY OF THE INVENTION It is the main objective of this invention to provide a finished shoe whose bottom can be quickly molded according to the bottom contour of a human foot at any time after the shoe has left the factory. This does not only eliminate the long break-in time and the disadvan- DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 is shown a cement lasted shoe. However, it should be understood that this invention is applicable to any kind of shoe construction. The insole 8 is made of thermoplastic material, for instance thermoplastic foam made of polyethylene, polypropylene, polyvinyl chloride, etc. Adjacent to the insole 8 are located electromagnetic energy-absorbing discs 4 which are shown somewhat enlarged for the sake of illustration. The electromagnetic energy-absorbing discs can be made of any conducting material such as steel, copper, aluminum, graphite, etc Also, the shape of the material 4 is functionally unimportant. Furthermore, the location of the electromagnetic energy-absorbing material 4 in the bottom of the shoe might vary with each type of shoe. For instance, it could very well be part of the filler material 6. In some cases it might be attached to the outsole 6. The upper 10 and its lining' 12 are made of a material which can withstand the activation temperature of the thermoplastic insole 8.

In FIG. 2 is shown a thermoplastic insole 8 which has been activated and molded according to the contours of the toes of the foot F.

In FIG. 3, the foot F with shoe rests on the coils 14 of an induction heating machine. In this illustration, the thermoplastic insole 8 is shown prior to activation and molding. Shoes which have been made with electromagnetic energy-absorbing material 4 located in an appropriate bottom area according to the construction of v the shoe, are shipped to a retail store as usual.

tages of mass-produced shoes, but also can be of particular importance for people who have crippled or ab- ,normal feet.

I able, and they will be referred to in conjunction with this invention only. When the thermoplastic material is "activated, and a person lets the weight of his body rest on the bottom of the shoe, the imprint of the foot will be in the shoe in less than a minute.

DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example, with reference to the drawings.

FIG. 1 is a perspective view of a shoe with a transverse section through the forepart area.

FIG. 2 is a transverse section of a shoe showing the insole contoured according to the toes of a foot.

FIG. 3 is a perspective view of a shoe with a foot in A retail store has to be equipped with an induction heating machine (not shown in the drawing). After a customer has selected a pair of shoes she puts them on and stands on the coils 14 of an induction heating machine. When the induction heating machine is turned on, an alternating electromagnetic field surrounds the coils l4 and transfers part of its energy to the electromagnetic energy-absorbing material 4. In the material 4 the electromagnetic energy is changed into heat. Then, this heat activates the thermoplastic insole 8 or a similar layer of plastic material in the bottom of the shoe. Under the weight of the body, the activated thermoplastic insole 8 will mold according to the contour of the bottom of the customers foot. Of course, the activation temperature of the thermoplastic material is such that the foot does not suffer from burns. Also, the

frequencies of an induction heating machine are not in any way dangerous to human health.

The construction of the shoe, the kind of thermoplastic material, and the shape and kind of electromagnetic energy-absorbing material will necessitate various embodiments without departing from the character of the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the i United States is:

l. A method of shaping the bottom of a shoe according to the contour of afoot, which comprises:

7 itand a cut-away view of the bottom area. The shoe is resting on coils of an induction heating machine.

joining a layer of thermoplastic material with an elec- ,tromagnetic energy absorbing material;

placing the layer of thermoplastic material in the bottom area of a shoe; exposing the shoe to an alter nating electromagnetic field of an induction heating machine thereby heating the layer of thermoplastic material to a temperature at which said layer becomes soft and moldable;

stepping into the shoe and pressing the foot on the bottom of the shoe thereby making an imprint of the foot in the bottom of the shoe; and

cooling thelayer of thermoplastic material thereby hardening said layer and maintaining the imprint in it.

2. A method of shaping the bottom of a shoe according to the contour of a foot; which comprises:

embedding electromagnetic energy absorbing particles in a layer of thermoplastic material; I

making the shoe in a shoe factory with said layer of thermoplastic material firmly and integrally lobottom of the shoe thereby, making an imprint of the foot in the bottom of the shoe; and cooling the layer of thermoplastic material therebyhardening said layer and maintaining the imprint in it.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3221353 *Jul 31, 1961Dec 7, 1965Greene Franklin RMethods of shoe manufacture using a radio frequency dielectric heater
US3493986 *Jan 22, 1968Feb 10, 1970Charles W ErwinHeat producing device
US3521385 *May 2, 1968Jul 21, 1970Dalebout Melvin WSki boot
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5714098 *Dec 20, 1995Feb 3, 1998Nike, Inc.Footwear fitting method
US5829171 *Dec 30, 1996Nov 3, 1998Perfect Impression Footwear CompanyCustom-fitting footwear
US5879725 *Sep 9, 1997Mar 9, 1999Nike, Inc.Footwear fitting system
US8959690 *Jun 29, 2012Feb 24, 2015Nike, Inc.Induction heating apparatuses and processes for footwear manufacturing
US20140000044 *Jun 29, 2012Jan 2, 2014Nike, Inc.Induction Heating Apparatuses And Processes For Footwear Manufacturing
EP0118319A2 *Mar 8, 1984Sep 12, 1984John Drew (London) LimitedProduction of insoles
EP0154170A1 *Feb 2, 1985Sep 11, 1985Keltsch, BernhardMethod of producing shoe insoles having an exact fit
WO1985003624A1 *Feb 18, 1985Aug 29, 1985Keltsch, BernhardMethod for fabricating shoe inner soles with adapted form
WO1991012740A1 *Feb 20, 1991Sep 5, 1991Loic DavidInner sole for footwear
WO2008052472A1 *Oct 26, 2007May 8, 2008Naiquan QianPhysical therapy shoe with electrical load powered by an induction generator and the power thereof
WO2014004759A1 *Jun 27, 2013Jan 3, 2014Nike International Ltd.Induction heating apparatuses and processes for footwear manufacturing
Classifications
U.S. Classification12/142.00R, 219/766
International ClassificationA43B7/28, A43B7/14
Cooperative ClassificationA43B7/28, A43B13/182
European ClassificationA43B7/28, A43B13/18A1