US3848286A

US3848286A - Method of and apparatus for custom molding footwear

Info

Publication number: US3848286A
Application number: US00449963A
Authority: US
Inventors: A Kahmann
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-03-11
Filing date: 1974-03-11
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19

Abstract

Footwear is formed of thermoplastic material. To better conform the footwear to the user''s foot, the user puts his foot within the footwear. A vacuum line is placed within the footwear and the top of the boot is sealed around the user''s leg to give a relatively airtight seal between the inside of the footwear and outside air. The vacuum line could alternatively be attached to a fitting which fits in a passage through the shell of the footwear. Then the footwear is heated to its softening temperature and a vacuum is applied to the vacuum line to evacuate the air from within the footwear allowing atmosphere pressure to exert a force on the footwear and press it against the user''s foot. While the vacuum is being maintained within the footwear, the footwear is cooled below its softening temperature so that the footwear will permanently conform to the user''s foot.

Description

United States Patent Kahmann [451 Nov. 19, 1974 METHOD OF AND APPARATUS FOR CUSTOM MOLDING FOOTWEAR [76] Inventor: Anthony J. Kahmann, 3032 Galena Ave., Simi, Calif. 93065 [22] Filed: Mar. 11, 1974 [21 1 Appl. No.: 449,963

[52] U.S. Cl. 12/142 P, 12/1 R, 36/25 AL [51 1 Int. Cl A43d 9/00, A43b [58] Field of Search.....-.. 12/1 R, 1 F, 142 R, 142 P;

36/25 R, 2.5 AL

Primary Examiner-Patrick D. Lawson Attorney, Agent, or F irm- Miketta, Glenny, Poms &

HEATER SOURCE ABSTRACT Footwearis formed of thermoplastic material. To better conform the footwear to the users foot, the user puts his foot within the footwear. A vacuum line is placed within the footwear and the top of the boot is sealed around the users leg to give a relatively airtight seal between the inside of the footwear and outside air. The vacuum line could alternatively be attached to a fitting which fits in a passage through the shell of the'footwear. Then the footwear is heated to its softening temperature and a vacuum is applied to the vacuum line to evacuate the air from within the footwear allowing atmosphere pressure to exert a force on the footwear and press it against the user's foot. While the vacuum is being maintained within the footwear, the

footwear is cooled below its softening temperature so that the footwear will permanently conform to the 13 Claims, 2 Drawing Figures COOLING SOURCE PATENIEmmv 1 sum HEATER SOURCE COOLING SOURCE METHOD OF AND APPARATUS FOR CUSTOM MOLDING FOOTWEAR BACKGROUND OF THE INVENTION This invention relates generally to footwear wherein it is desirable to have such footwear conform to the users foot.

It has been recognized that it is desirable to have a boot or shoe which conforms to the users foot when strains are being applied thereto. Foot strains occur during exercising and general athletics, but sports such as skating, football, hiking and mountain climbing are known to provide more severe strains to the participant's foot. However, because of its fast speed and be cause the foot is constantly under strains from a variety of sources, skiing provides the greatest strain to an athletes feet.

Even in ordinary footwear, there is a need for a shoe or boot which will better support the foot being of such a size that the users foot will not slide or be held too tight at any portion of the shoe. Unfortunately, there are only a limited number of different sizes of footwear corresponding to standard lengths and standard widths, and two people who have the same size foot do not necessarily have similarly shaped feet. With ordinary footwear, this difference is usually not crucial unless there is an abnormality in the foot. However, these small foot differences are magnified when forces during athletics are applied to the foot and shoe.

There have been numerous attempts to provide footwear that better conforms to the wearers foot. In the field of ski boot manufacturing, these attempts have generally taken four directions. These methods have their greatest application in ski boots but they have application in general footwear as well.

The first method is to have a ski boot of soft material with adjustable buckles so that the tightness of the shoe can be modified. This is an older method and it is similar to that employed in ordinary footwear wherein the laces may be adjusted to make the boot or shoe more comfortable to the user. This method has drawbacks because the laces do not cover the entire foot but merely serve to tighten the boot about the instep, and the softer material, which has the ability to be laced tightly, does not provide the support to the lower leg and ankle necessary for efficient skiing.

The second method of improving the fit of a boot is to provide an expandable material between the inside of the boot and the users foot. In that system, the internal portion of the boot may be fitted with a bladder which can be filled with air to have the bladder apply pressure to the foot and prevent movement within the boot. Another method on the same principle is to have a moldable foamed plastic injected within the boot when the users foot is therewithin, then allowing the material to expand, cool and reach its hardened temperature. These methods are improvements over the buckle and lace methods of having the boot formed to the foot, however, these methods also have some drawbacks. The use of foam plastics requires that the user remain fairly stationary within the boot for upwards of onehalf hour while the material cures. This is time consuming and uses up valuable time of sales personnel selling the boot. Also, the rather hot foamed plastic. that is injected within the boot is uncomfortable to the user. Changes in the users foot, for example from gaining weight, injury, or the like, cannot be compensated for because the foam injection alters the boot permanently. The air bladder method has the drawback that the air cannot completely cushion the foot from the violent moves in skiing. Also, the air bladder is somewhat cumbersome to fill each time the boot is to be used.

A third method of improving the fit of a boot is to provide an inner boot, inside the outer shell, which holds a jelly like material which conforms to the wearers foot when pressure is placed against it. This flow material is generally placed in the inner boot at the point of manufacture. The drawbacks of the flow system are that the flow is subject to compression after prolonged use which results in a poorer fit, and conformation of the flow to the wearers foot causes variable thicknesses of flow material which separates the foot from the outer shell, further causing pressure points on the foot.

A fourth method has been proposed by Geller, in U.S. Pat. No. 3,613,271, dated October, 1971. The method concerns having a ski boot made from thermoplastic material which is moldable at a temperature between and F. The boot is placed on the wearers foot and brought up to temperature. When it reaches the desired temperature, the user or other person pushes the sides of the boot against the foot with his hands. Instead of hands, a pressure cuff could also be used. This has certain advantages over the other systems. First, a conventional thermoplastic ski boot may be used which can be modified by this process. Secondly, the boot may be remolded at a later time to accommodate changes in the structure of the users foot. Thirdly, the skier does not have to take preliminary steps such as inflating the bladder prior to each use.

There are certain drawbacks to this system. By having a boot moldable at a temperature between 120 and 140F, the boot could become soft in the trunk of a car thereby changing the boots shape. The use of hands to compress the boot about the foot causes uneven pressure application and can result in having a boot too tight in certain places and too loose in others. A pressure cuff does not alter this condition because its application of forces is also uneven.

It is, therefore, an object of this invention to provide a boot or shoe which will not have the drawbacks of prior art footwear. Primarily, it is an-object of this invention to provide a system to conform a boot to the user's foot to fit the users foot evenly and tightly over all parts of the foot. Also, an objective of the invention is to provide a boot that will not melt or soften at temperatures likely to be reached in normal use. A further object is to correct the shaft of the boot, the angle which the leg makes with the foot. A further object of the invention is to provide a system whereby the foot is protected from hot material to thereby ease discomfort.

BRIEF DESCRIPTION OF THE INVENTION These objects are accomplished by having a system for providing support for the foot which includes boot means formed with a shell of moldable material. Thereafter, vacuum means acting inside the boot means causes the ambient pressure around the boot to exert a force on the shell. Heating means cause the shell means to reach a moldable temperature whereby the ambient pressure acts on the shell when the shell is at the moldable temperature to cause the boot to form to the foot. Then cooling means are applied to the boot while the vacuum is being maintained until the boot drops below the molding temperature. The users foot may be withdrawn from the boot and a boot of perfect fit is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a side view of the boot. FIG. 2 is a sectional view through section II-II of FIG. 1 of the boot.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT:

Boot means are formed with a shell of moldable material. In the preferred embodiment, such boot means is formed of a shell 17 formed of a thermoplastic material which is rigid at room temperature and becomes moldable with memory between l80F and 380F, is preferably about 350F. At that temperature, a compromise is reached between the highest tempera tures to which the foot can be subjected and temperatures to which the boot might ordinarily be subjected in a heated automobile trunk or near a fireplace or wall heater. The shell is lined with neoprene rubber at 16 also of a consistent thickness for insulation from heat and cold and for evenly cushioning the foot from the hard plastic material. The boot also comprises a sole 11 made to conform to a ski binding, an ankle portion 12, and an instep portion 13. Additionally a buckle l4 and 15 allows the. instep portion 13 to be moved to allow insertion and removal of the foot.

Sealing means for placement around the upper opening of the shell seals the inside of the boot means from the outside air. In the exemplary embodiment, such sealing means 2 fits tightly around the top of the boot and the users leg 1 to prevent air from entering the boot through the leg opening. The seal extends down over the most open areas of the instep 13. The seal means 2 should be as tight as possible and should be of non-porous material to prevent the entrance of air within the boot adjacent the leg 1.

Vacuum means lowers the pressure within the boot means below ambient pressure so that atmosphere pressure exerts a resulting force on the outside of the boot means to apply external pressure to the shell. In the exemplary embodiment such vacuum means 50 includes a tube 51 connected to a source of vacuum (not shown) nearby. The vacuum line 51 is placed within the boot between the boot shell and the leg preferably near the instep.

In an alternative embodiment, a passage means is provided through said shell for connecting said vacuum means beneath said shell. Preferably, a fitting 53 fits through the passage and extends slightly outside the shell 17 so that the vacuum tube can be attached thereto. See FIG. 2. The fitting, and consequently the passage, extend also through the boot lining l6 and terminates in a fiat rounded portion to protect against injury to the foot. A check valve may be provided to prevent air from flowing from the vacuum line back into the boot through the passage.

The vacuum means 50 applies a vacuum through the vacuum tube 51 to create a lower pressure within the boot then outside thereof to cause a resulting pressure on the external surface of the shell. Heating means thereafter heats the shell means to a moldable temperature whereby the vacuum acts on the shell to cause the boot to conform to the foot. In the exemplary embodiment, such heating means comprises a heater source 30. The heater source could be many different heating means. It has been found that an industrial hand-held blower with an electrical resistance heating element is a preferred source of heat. These heating blowers are capable of directing hot air at a specific location by holding the output end of the blower near that location, or they can heat a general area by holding the output end farther away from the material to be heated. This feature allows flexibility in the use of this invention. Such heating blowers are capable of temperatures high enough to heat the shell to its softening point, about 350F. It is also possible with this type of blower to direct the heat away from the uncovered portion of the users leg.

Another heat source which may be used is a miniature electric blanket. Preferably, the heating elements are within a heat resistant and electrically insulated material. The blanket has the same area as the area of the largest boot sold, and is designed and shaped to fit on a boot with minimum folding. Alternatively, more than one blanket, each of a particular shape to heat a particular section of the boot,'could be used.

The blanket has certain advantages. For example, heat is more evenly applied to the boot and there is less use of energy than with a blower. The blanket system also would be quieter than a blower which is important to a retail store where excess noise would irritate customers. If multiple blankets are used, heating of particular sections may be accomplished if desired. Other known heat sources could also be used but it is advantageous that they be portable and may be applied without moving the boot.

As the shell reaches its softening point, the atmospheric pressure will exert forces on the shell to cause it to move inwardly to conform to the users foot. If the boot is too tight when bought, the force exerted by the users foot against the boot will cause it to expand slightly to evenly conform to his foot. It has been possible to develop a high vacuum within such an arrangement and the atmospheric pressure can act very quickly on the shell. Therefore, it is unnecessary to maintain the boot at an elevated temperature for a long period of time. There is no discomfort to the wearer because his foot is protected by the neoprene liner l6 and optionally by a sock. Depending on the effectiveness of the seal means, the amount of vacuum can be varied by adjusting the source of vacuum to achieve a desirable resultant force on the shell while not causing an extremely high vacuum within the boot which would cause discomfort to the user's foot.

While the pressure is maintained on the shell, the shell cools below its molding temperature. This cooling may be accelerated by applying a cooling means to the boot while the vacuum is maintained at least until the temperature of the boot drops below the softening temperature. In the exemplary embodiment such cooling means includes a cooling source 40. Preferably, this cooling source is an aerosol coolant which can be sprayed directly on the outside of the shell. This method will cool the boot very rapidly. Of course a water bath could also be used but it is desirable that the foot not be moved during the process so that the boot will conform to the users foot when it is in its supporting position. It is advisable to maintain the vacuum at least until the boot drops below the molding temperature so that forces exerted by the foot outside against the inside of the shell will not cause any nonconforming regions within the boot.

Shaft of a ski boot is defined as the angle which the ankle portion of the boot 12 makes with the rest of the boot. It should conform to the angle which the leg makes to the foot. The concept of a shaft can be illustrated by picturing a set of regular leather boots which have been worn for some time. If they are placed on a flat surface, a slight bend should be evident about the ankle, and the boot should naturally maintain this angle or shaft. The present device assures a correct shaft because the user should be standing naturally on a flat surface, and as heat is applied to the top portion of the boot, it will bend slightly to assume the correct shaft.

It should also be noted that by allowing outside air to be the source of pressure to the shell, the heating and cooling means can be applied to the boot while the boot is under-going pressure deformation. This is important because the boot would have to be heated to a higher initial temperature so that the pressure applying means could be placed around the boot as the boot cooled to its minimum molding temperature. Also, the pressure applying means would have to be removed from the boot if cooling means were applied to the boot and without such pressure, the boot could deform during cooling. 'Without the use of cooling means so that the pressure could be maintained, the warm boot would stay on the users foot a longer period of time, and if the pressure means is still around the boot, it inhibits ambient air from reaching the boot to cool the shell.

Because the boot may be heated and cooled quickly, boots of a material of higher softening temperature may be used. This guards against accidental deformation of the boot from the heat of a fireplace or in an automobile trunk. Also, the neoprene lining protects the foot during the short heating period.

If for any reason the shape of the users foot changed, the process could be repeated quickly. If the user decided to sell his boots, his custom formed boots could be modified to become the buyers custom boots if their feet are of similar size.

The system has been discussed with respect to ski boots but could be adapted for any type of footwear. Instead of the ski sole 11, shown in the exemplary embodiment, the bottom of the boot could be attached to roller skating or ice skating apparatus. The system could also be used with conventional footwear or for I claim:

l. A method of forming a boot or shoe of moldable material to better conform it to a users foot after hav ing placed the boot on the users foot including the steps of:

a. applying a vacuum beneath said boot;

b. applying sufficient heat to the boot for the boot material to become moldable while maintaining the vacuum so that the vacuum will cause the boot to mold towards the foot to conform thereto.

2. The method of claim 1 further including the step of applying cooling means to the boot at least until the boot material drops below the molding temperature while maintaining the vacuum.

3. The method of claim 1 including the step of providing sealing means about portions of the boot through which outside air could flow into said boot to diminish the vacuum, said sealing means preventing said flow of air.

4. In a system for providing better support for a foot:

boot means formed of a shell of moldable material;

vacuum means for acting inside said boot means for lowering the pressure within said boot means below ambient pressure so that atmospheric pressure exerts a resulting force on the outside of said shell;

heating means for heating said shell to a moldable temperature whereby the vacuum acts on said shell when said shell is at a moldable temperature to cause said boot to conform to the foot.

5. The system of claim 4 further including cooling means for cooling said boot at least below the molding temperature while the vacuum is maintained at least until the boot drops below the molding temperature.

6. The system of claim 4 further including sealing means to prevent loss of vacuum within said boot.

7. The system of claim 4 further including passage means through said shell for connecting said vacuum means beneath said shell.

8. The system of claim 7 wherein said passage means includes check valve means to allow air to flow from the boot through said passage means and preventing air from flowing from outside said boot through said passage into said boot.

9. In an improved system for conforming a shoe or boot to a foot including:

boot means of material which is moldable at a certain temperature;

heating means to heat said boot to said temperature;

and

pressure applying means to mold the boot to the foot,

the improvement including the provision of having;

a. said pressure means includes means to apply a vacuum from within said boot to cause said boot to collapse around the foot.

10. The improved system of claim 9, further including a provision of having a sealing means around portions of said boot through which outside air could leak to decrease said vacuum within said boot means, said sealing means preventing said leak through said portion to maximize said vacuum within said boot.

11. The improved system of claim 10, further including the provision of having cooling means for acting on the boot while the vacuum is maintained to cool the boot below the molding temperature.

12. The improved system of claim 9, further including the provision of passage means through said shell for connecting said vacuum means beneath said shell.

13. The improved system of claim 12 further including the provision of having said passage means include check valve means to allow air to flow from the boot through said passage means and preventing air from flowing from outside said boot through said passage into said boot.

Claims

1. A method of forming a boot or shoe of moldable material to better conform it to a user''s foot after having placed the boot on the user''s foot including the steps of: a. applying a vacuum beneath said boot; b. applying sufficient heat to the boot for the boot material to become moldable while maintaining the vacuum so that the vacuum will cause the boot to mold towards the foot to conform thereto.

4. In a system for providing better support for a foot: boot means formed of a shell of moldable material; vacuum means for acting inside said boot means for lowering the pressure within said boot means below ambient pressure so that atmospheric pressure exerts a resulting force on the outside of said shell; heating means for heating said shell to a moldable temperature whereby the vacuum acts on said shell when said shell is at a moldable temperature to cause said boot to conform to the foot.

9. In an improved system for conforming a shoe or boot to a foot including: boot means of material which is moldable at a certain temperature; heating means to heat said boot to said temperature; and pressure applying means to mold the boot to the foot, the improvement including the provision of having; a. said pressure means includes means to apply a vacuum from within said boot to cause said boot to collapse around the foot.