US2979835A - Foot cushioning device - Google Patents

Description

April 1961 w. M. SCHOLL 2,979,835

FOOT CUSHIONING DEVICE Filed April 28, 1958 frg? 511 E W/ZZ/A/V M SC/VOZZ United States Patent FOOT CUSHIONING DEVICE William M. Scholl, 211-213 w. Schiller St., Chicago, 111.

Filed Apr. 28, 1958, Ser. No. 731,541 g 1 Claim. or. 3644) This invention relates to improvements in a foot cushioning device, and more particularly to a device for disposition in an article of footwear beneath the plantar surface of the foot, the invention being highly desirable for use as a cushion type full or partial insole, although it may take other formsas will be apparent to one skilled in the art. e

In the making of foot cushioning devices heretofore, and particularly foot cushioning devices such as full or partial insoles, difliculty has been experienced in constructing an insole that would lie flatly in an article offootwear such as a shoe, because of the fact that the structural insole of the shoe in mostcases turns upwardly slightly in the marginal portions. Further'difliculty has been experienced in providing foot cushioning devices underlying the forward part of the foot that did not' cramp the toes by occupying too much space in the forward part of a shoeor the like, and thus causing a crowded condition for the toes. Extreme difficulty has also been heretofore experienced in providing a cushion type insole or other footcushioning device that is comparatively extremely thin and yet provides adequate cushioning relief. I

With the foregoing in mind, it is an'important object of the instant invention to provide a foot cushioningfievice so constructed as to lie flatly in the shoe and overlie'the edges of the structural shoe insole and compensate for the upwardly turned margins of that structural insole. p

Also an object of the invention is the provision of ,a foot cushioning device which may be constructed in the form of a cushioning insole, and which comprises a cover layer and an underlayer of cushioning material whiehi is secured to the cover. layer by a marginal seam, the cushioning material being thicker and curving toward .the upper layer inside the relatively thin marginal seam. Also a feature of the instant invention is the provision of a foot cushioning device comprising .a-relatively thin cover layer, a thicker layer of cushioning material joined to the cover layer by a thin marginal scam in the nature ofa lateral flange substantially in the plane of the cover layer, while the underlayer curves tjoward the'cover' layer inside the seam.

a p A further object of the instant inventionisfthe'provision of a foot cushioning device including a relatively thin cover layer. and 'a-thicker underlayer of cushioning materialsecured to the cover. layer by. a marginal seam in which the" cushioning materialtis compressed to i'substantially the thickness of the cover,iand"which se'am gradually widens in the forward portion of the device until it reaches maximum width at the anterior end of v 1 the device, thereby providing ample toe room within the article of footwear.

graduates in width in the forward portion of the device, reaching its maximum width at the anterior end of the device, the cushioning material being compressed in the heat seal seam and the density of the cushioning material in the widest part of theheat seal seam varying from a maximum at the anterior end of the device to a lesser amount in the inner portion of the seam at that end of the device.

Also a feature of the invention is the provision of a foot cushioning device which may preferably be madein the form of an insole, and which embodies a cover layer and a thicker layer of cushioning material, the cushioning material decreasing gradually in thickness in the forward portion thereof to merge with a relatively wide heat seal seam of considerably less thickness than the cushioning layer alone in its body portion. While some of the more salient features, characteristics and advantages of the instant invention have been above point d out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawing, in which 7 U .Figure'l is a bottom plan yiew of a cushioning insole embodying principles of the instant invention;

Figure 2 is a fragmentary enlarged top plan view of the rear or lefthand end ofthestructure of Fig. 1;

Figure. 3 is an enlarged transverse vertical sectional view taken substantially as indicated by the line III'III of Fig. 1, looking in the direction of the arrows; and

'Figure 4 is a fragmentary enlarged v rtical sectional view taken substantially as indicated by the line IV-IV of Fig. 1.

' As shown on the drawings:

Whi e the instant invention maytake a number of several different forms and sizes as will be apparent to one skilledin the 'art, the invention lends itself quite favorably for use as a cushion insole, and by Way .of illustration, therefore, an embodiment of the invention has been selected for illustration and description herein which is in the form of a cushion type insole of a size to underlie the complete plantar surface ofthe human foot. Also,

in the illustrated instance, the insole'is of the type that is placed freely in an article of footwear on top of the structuralinsole of the footwear. It is to be understood that for;.purpos'es of clarity the invention is-illustratedin Figsr l, 3 and 4 in inverted position. I The illustrated embodiment of the instant invention comprises a relatively thin cover sheet 1 which is preferably a thermoplastic; material such as an unsupported vinyl film.. Preferably the sheet 1 is provided with-numerous perforations 2 as seen clearly in Fig. 2. 1 A she et dot cushioning material is secured to the underface of the cover sheet 1 preferably by a marginal V seam 4, vvhich is. also preferably a heat seal seam. The

- polymer in one or more plasticizers selected from a large Another feature of the instant invention'resides in the provision of a foot cushioning device comprising a cover layer and a thicker layer of cushioning rnaterial joined to the cover layer by a marginal heat seal seam which cushion sheet 3-,is considerablythicker thanthe cover s heetland is alsoipreferably atherrnoplastic material, a chemical foam such as;vinyl foam being ,highly satisfactbry for lthe purpose. a one satisfactory example of aycushioning material which may readily beheat sealed is vinyl team made ifrom'fa liquid composition generically ,known as ajplas;

9 -1 T1 P i li li -sx mlsd p a y sa inift-tgas d th n u d; in h e pandeshcqnditidn to" provideaflightweight structural material which is highly flexible, resilient, and possesses intercommunicat- 1 ing cells. The plastisol may satisfactorily be a disper-,

sion or suspension of polyvinyl chloride resin, or a co number of high boiling esters, for example, such as dioctyl phthalate, dioctyl adipate, dicapryl phthalat'e, etc.

Such materiaL'yvhen compared with a material such as foam latex, is more shock absorbing, more resistanttofoot during use.

'The cover -1 maybe of'the, same material, insofaras chemical constituents are concerned, as the cushion layer :3, 'but'in the instance of the cover no expansion of the ingredients is caused, but they may be chargeddirectly into a Banbury mill and then passed between calender -rolls,- whioh"results in a very much thinner and denser product, commonly referred to as a'film. V The cushion layer '3, if a'foam, has' intercommunicating-cells, whereby during use air willbe pumped into and out of, as well as through the cushion layer. This, coupled with the apertures 2 in the cover sheet '1, provides adequate ventilation for both the device'and'the The two layers or sheets 1 and 3 are preferably heat sealed together at the bounding margin only, remaining unsecured to eachother in'the intermediate region where- -by wrinkling of thedevic'e orpermanent creasing thereof during use is avoided. The heat scaling is preferably accomplished with suitable dies by way of a high frequency electronic process. -'-With the instant invention,

one of those dies is preferably so shaped and constructed 5.:

as to provide a graduated eflect in the region of theheat seal searn. 'With reference to FiglB, it may thus be's'een .that this-effect causes'a curving of the marginal portion .ofthe cushion 'sheet 3 toward the cover sheet 1, as indicate'd'at *5. In the actual seam, the cushion material is compressed and held compressed to substantially the same thickness as the cover sheet, as indicated at 6 in Fig. 3. Thus a thin and narrow heat seal seam 4- is provided which is in the nature'of a lateral flange substantially in the plane of the cover sheet. Thus, when thefinished device is placed in a shoe or the like, the curvate margin-50f the cushion sheet 3 compensates for the upward curvature of the marginal portion of the structural insole in the shoe, while the heat seal seam 4 which is elevated above the underface of the cushion sheet 3 ove'rlies the edge of the structural insole. Accordingly, the instant invention lies flatly in'a shoe and presents a flat upper surface to the foot of aus'er, adequately compensating for thedeviation from flatness in ordinary shoe construcon the device, itwill'yield to any protuberance or excrescence of. the foot and adequately cushion the foot throughout-the entire surface ofcontact." 7

' .l. Another important feature of thje instant' invention is best-shown in Figs. 1 and 4." That'is the factthat" the the seamreaching its widest part 7 at'the anterior end of c 7 .tion; LAt' thesarne time, when thebody weightisplaced the. device." The-widening of that seam'in theanterior portion-of the device of course results in the decrease in ythicliness of the cushion sheet in that'region so as to provide adequate toe room for the user, and not cause a crowded condition within: the toe portion i o'f the shoe.

- 1 '-As seen best in Fig.4,as the-heat seal seamis widened *in' the region '7, the cushion layer 3 gradually increases' in thickness, toward the inner portion o f' the seanu and i V gtherebythe seam a variation indensity, being denser ;(pages-106 l08, 2l45216inc1.).

4 at the outer forward edge than it is at the inner part of the wide portion of the seam. This causes a gradual lessening in the cushioning characteristic of the device toward the ends of the toes, with no abrupt change in character present.

For the purpose of aiding'in the provision of ample toe room in the shoe and also to provide the lessening of cushion effect towardthe tips of the'toes, another structural feature is incorporated in the instant invention. This feature resides in the gradual decrease in thickness of the cushion layer in the forward portion thereof, as indicated by numeral 8in Figs. .1 and 4. In the illustrated instance, this gradual decrease in thickness occurs from substantially the dotted line 9 shown in Fig. 1. While the decrease in thickness of the cushion sheet 3 may be molded into the sheet 3 if the same is molded, it is preferable to slice the sheet 3 from a thick piece of stock, and provide the decrease in thicknessby a skiving action during the slicing operation.

lt'will be noted that ample toe room is provided in a shoewhen the decrease in thickness at 8 of the cushion sheet -3 is coupledfwith the widened seam portion 7, and yet the fullcushioning effect of the sheet 3 is maintained throughout the greater portion of the 'device.

From the foregoing, it will be apparent that I have provided asimple form of foot cushioning device which 'dition in ordinary articles of, footwear, and which allows ample-toe room at'all times. Further, the device may be made in-any color, is extremely clean in appearance, may be laundered at will, is not adversely affected by foot acids, detergents, and the like, resists fungus, bacteria and the like, and is extremely light in weight.

It will be understood that modifications and variations may be effected without departing from the scope of the 'novel concepts of the present invention. 5

I claim as my invention:

A heat sealedflat cushion insolefor free disposition in an article'of footwear, comprising a relatively thin flat vinyl cover sheet for disposal; against the foot of the wearer and a relatively thick fiat vinyl foam, pad coextensivewith said sheetand secured thereto by'a heat seal seam alongthe'bounding edges only of said sheet and pad, saidpadhaving a curvate-inargin along thelower surfaceonly thereof compressed to the'same'thickness as the cover sheet with the marginal edges of said sheet and pad'b'eing' relatively flatfthe heat seal seam substantially in the" vicinity of the'metatarsal'heads being substantially wider and the curvate margin of'the pad being of greater density andlesser thickness along the outer forward 'edge anddecreasing infdensity and increasing in thickness a controlled distance rearwardlyfrom said for;

warded ge. V I v i V a f- ReferencesCited in the tile ofthis patent; h 'JUNITED STATES ar-ants Modem Plastic Periodical, vol. 32, November 1954

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