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METHOD OF PRODUCING CUSTOM-FITTING ARTICLES AND COMPOSITION FOR THE USE THEREWITH
This application is a continuation-in-part of application 5 Ser. No. 08/002,281, filed Jan. 8, 1993, now abandoned which is a continuation-in-part of application Ser. No. 07/972,237, filed Nov. 5, 1992, now abandoned.
BACKGROUND OF THE INVENTION 10
This invention relates in general to custom-fitting articles and compositions useful in making same and in particular to custom-fitting articles which conform to the shape of a body part of a mammal, particularly a person. 15
DESCRIPTION OF RELATED ART
Many articles which are intended to conform to the shape of a body part of a mammal, such as a person, for example, 20 certain footbeds for footwear, hand grips, protective pads and padding, and medical and veterinary appliances, are not custom-fitted. It has long been recognized that it is advantageous to custom fit articles of these types to the particular conformation and shape of the body so that the article is 25 more comfortable to wear and the weight and pressure is distributed more evenly.
With regard to custom-fitting footwear, there have been a number of approaches. In one approach, a chemical reaction is initiated in a formable material in a footbed, the person 30 then steps into the footwear or shoe and forms an impression and the material is allowed to cure before the footbed is used. See U.S. Pat. Nos. 4,520,581; 4,128,951; 2,838,776; and 4,888,225. U.S. Pat. No. 3,968,577 illustrates a system in which an impression of the foot is made, and the material 35 is cured or set either pursuant to room temperature vulcanizing or by being heated in an oven for an unreasonably long period of time.
Other patents disclose a shoe or sandal having a bottom layer of a thermoplastic material. The thermoplastic material 40 is heated, thus softening it. The person steps into the shoe and makes an impression. The material then cools, retaining the impression of the foot. See U.S. Pat. Nos. 3,641,688; 4,413,429; 4,433,494; 4,503,576; 3,895,405; and 4,901,390. All the foregoing patents are incorporated herein by refer- 45 ence.
These approaches suffer from a number of deficiencies. Once a catalyst is added, the activation may be irreversible and the impression may have to be made quickly. Some 5Q catalysts may require kneading, which is difficult with viscous material and time-consuming. Making an impression in hot thermoplastic material may be dangerous to the foot and it is not possible for the customer to feel how the shoe will fit prior to heating. 55
Most hand grips, such as for bicycles, sports rackets, ski poles, etc., are not custom-fitted; they are made so that one size fits all. Most body pads, such as knee pads, elbow pads, helmet pads, shin guards, etc. are also made so that one size fits all. Many prosthetic or orthopedic casts, splints, and go braces do not have, biased against the body part, a customfitted flexible yet resilient member conforming to the body part to cushion and more evenly distribute the weight or pressure.
It is an object of this invention to provide a method of 65 producing a custom-fitting article which overcomes these deficiencies, the method being quick and effective and which
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the customer can perform at home and producing a member which remains flexible while resiliently retaining the impression of the body part. It is also an object to provide a member or article which the purchaser or user can test for feel and fit before the impression is set.
SUMMARY OF THE INVENTION
A method of producing a custom-fitting article which conforms to the shape of a body part of a mammal is provided. The method includes providing a member comprised of a body of formable material, the body of formable material having a minimum setting temperature greater than 130° F. and being setable by heating for a period not exceeding 30 minutes and subsequent cooling. The member is conformed by biasing the member against the body part with sufficient pressure to conform the member to the shape of the body part. The member is then heated for a period not exceeding 30 minutes and thereafter cooled so that the formable material is set and the member remains flexible while resiliently retaining an impression of the body part. The member is utilizable by the mammal as part or all of the custom-fitting article. A member for use in connection with the method is also provided. A composition is also provided which comprises uncured silicone rubber, an effective amount of crosslinking agent, and effective amounts of a) fine powder ethylene copolymer or terpolymer or a mixture thereof and b) liquid plasticizer to form a gel effective to receive and retain an impression, the composition having a minimum setting temperature greater than 130° F. and being formable and setable to form a flexible and resilient body.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of footwear, specifically a sandal, according to the present invention. FIG. 2 is an exploded view of the sandal of FIG. 1. FIG. 3 is a sectional view taken along line 3—3 of FIG.
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FIG. 4 is a perspective view of a removable insole in accordance with the present invention.
FIG. 5 is a sectional view taken along line 5—5 of FIG.
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FIG. 6 is a perspective view, with a portion cutaway in cross section, of a gel pad or member for forming a hand grip.
FIG. 7 is an exploded view of the hand grip gel pad of FIG. 6 on the handle portion of a tennis racket.
FIG. 8 is a perspective view, with a portion cutaway in cross section, of a shin guard according to the present invention.
FIG. 9 shows the shin guard of FIG. 8 on the shin of a person.
FIG. 10 is a perspective view of a pair of glasses with a nose pad and two ear pads according to the present invention in place.
FIGS. 11 and 12 are perspective views of the nose and ear pads, respectively, of FIG. 10.
FIG. 13 is a perspective view, with a portion cutaway in cross section, of a bicycle seat pad according to the present invention.
FIG. 14 is a perspective view of the underside of the bicycle seat pad of FIG. 13.
FIG. 15 is a perspective view of an ankle cast about to be positioned on an ankle.
FIG. 16 shows the ankle cast of FIG. 15 in position.
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DESCRIPTION OF PREFERRED
EMBODIMENTS
A footbed supports the foot when footwear is worn and/or provides the bed upon which the underside of the foot rests 5 when footwear is worn. As used herein the term "footbed" includes a removable insole or innerliner. Thus a footbed may be a separable or integral component of footwear. Footwear includes sandals, shoes, slippers, and boots. Footwear, which also includes socks for diving suits, swimming Q flippers, water and snow ski boots, and skates such as ice skates and inline skates, is worn on the foot.
With reference to FIG. 1, there is shown footwear, specifically a sandal 10 for a person's left foot. The sandal has a toe end 15, a heel end 17, an outside 19, and an inside 13 15 (see FIG. 2). The sandal includes a top sole 18, a bottom sole 12, and a strapping mechanism or system, preferably made of % inch tubular nylon webbing, to hold the foot. The top sole 18 has a side 14 which meets the bottom sole 12 at margin 16. The toe strap 20 has a lower lateral portion 33 20 which passes through D-ring 34 and continues as upper lateral portion 35, which is secured to lower lateral portion 33 by hook and loop fasteners, such as Velcro. Toe post 22 secures the D-ring to the sandal. Heel posts 24 and 26 secure the heel portion of the strapping mechanism to the sandal. 25 The strap which forms heel post 26 continues as lateral strap 38 which is secured by stitching to lower lateral portion 33 and continues as lateral strap 36 through the loop formed by heel post 24, continuing on to form heel strap 25, continuing through the loop formed by heel post 26 to form instep strap 30 30 which can be cinched down through a cinching mechanism in quick release clasp 32. Once the instep strap 30 is properly cinched down, the wearer can take the sandal on and off using quick release clasp 32. Any quick release clasp as known in the art can be used. Heel strap 25 goes around 35 the heel of the wearer. Instep strap 28 is secured at one end to heel post 24 and at the other end to the portion of the quick release clasp opposite the cinching mechanism. Other strapping mechanisms or systems as are known in the art can be utilized in connection with the present invention. 40
With reference to FIGS. 2 and 3, there are shown three principal elements of the sandal, including the top sole 18, the bottom sole 12, and the gel layer 50 disposed therebetween. The top sole 18 and the gel layer 50 constitute the member which is used to produce a custom-fitting footbed. 45 The top sole 18 and the gel layer 50 support the foot when the sandal is worn and provide a bed upon which the underside of the foot rests when the sandal is worn. The bottom portions 44 and 46 of the straps 20-22 and 24-26 respectively, are attached by gluing means or other methods 50 known in the art, to the inside surface 48 of the bottom sole 12. The reinforcing strips 45 may be similarly attached to further secure bottom portions 44 and 46 to the bottom sole 12. The gel layer 50 preferably comprises a body of formable material, specifically gel material 57, encased in an 55 envelope 59, preferably airtight, for ease of handling and to keep the gel and any fumes contained. Alternatively the gel material may be unencased. The gel layer and gel material are formable and conformable. Slits 40 are cut or otherwise provided through the gel layer 50 and top sole 18 to permit 60 straps 20, 22, 24, and 26 to pass therethrough. The margins of the envelope 59 at slits 40 are preferably sealed to contain the gel material. The top sole 18 has on its underside a cavity defined by top surface 52 and sides 54. The gel layer 50 has a top 56 and sides 58. The upper portion of the gel layer nests 65 in the cavity of the top sole 18. The bottom surface of the gel layer rests on the inside surface 48 of the bottom sole 12.
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The beveled surface 42 of the top sole engages the beveled surface 49 of the bottom sole when the sandal is assembled. Lateral flow of the gel layer 50 is thus partially restrained by sides 54, assisted by downward force applied by the foot to engage beveled surface 42 with beveled surface 49.
With reference to FIGS. 4 and 5, there is shown a removable insole 60 which constitutes the member used to produce a custom-fitting footbed. The insole 60 comprises a formable material, specifically a gel material 62, preferably encased in a flexible envelope or pouch 64 preferably heat sealed around the perimeter such as at 66 and preferably airtight to contain fumes, to protect from contamination, and to prevent the possibly sticky gel material from sticking to the person or other objects. The removable insole has the general shape of the underside or bottom of a person's foot or of the interior bottom of a shoe.
The top sole is preferably a light weight sponge or elastomeric foam material, with or without a fabric cover. Alternately, the top sole can be of a similar material to the bottom sole or a light weight fabric. The top sole is flexible and able to conform to the shape of the gel layer. The bottom sole is preferably a blend of SBR and natural rubber, containing normal rubber additives such as Hi-Sil ABS, which acts as an impact modifier, and accelerators for vulcanization. It can be molded in cast aluminum molds at 350° for 4 to 5 minutes using techniques well known in the art. Other polymeric or other materials, including foams such as flexible foams to reduce weight, known in the art may be utilized for the top and bottom soles. These materials and all the non-gel material parts of the footwear should be able to tolerate the microwaving and/or oven heating described hereinafter. The bottom sole is flexible to permit walking.
The envelopes 59 and 64 are preferably made from aromatic polyether polyurethane thermoplastic film available from Deerfield Urethane, Inc., South Deerfield, Mass. Alternatively they can be made from a coextrusion with nylon or polyester on the outside to provide heat resistance and an olefin on the inside to allow the envelope to be heat sealed. Such coextrusions are available from Roll Print Packaging Products, Inc., Addison, 111. or Custom Co-Ex, Atlanta, Ga. The envelopes 59 and 64 should preferably be able to withstand the heating process described hereinafter and should be non-crinkly, compliant, flexible and able to conform to the shape of the foot or body part as it makes an impression in the gel material. Alternatively, a piece of woven polyester, such as available from DuPont as SANDED COOLMAX, or a piece of leather can be attached to the surface of the envelope 64 that will be next to the foot or body part to provide more absorbency and to make the member or article more comfortable. Preferably, the envelopes are made from two layers (top and bottom) and are heat sealed using an RF sealing machine available from Callanan in Elk Grove, 111.. This yields a feather edge as shown at 66.
With reference to FIGS. 6 and 7, there is shown a hand grip gel pad or member 70 comprising a flexible envelope 74 containing a body of formable material, specifically gel material 76. The gel pad 70 has end tabs 71 and 72. On the surface of the end tabs are hook and loop fasteners, such as Velcro, for securing the gel pad in frictional engagement around the handle portion 79 of the tennis racket 78. The gel pad can be affixed to the handle portion by other attachment means, such as snaps, adhesive, Velcro, stitching, or insertion into a pre-existing pocket such as a fabric pocket. Alternatively, the gel pad may be permanently integral with the handle portion, in which case the handle portion may
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