US2917849A - Shock absorbing insole and arch cushion - Google Patents

Description

Dec. 22, 1959 w. M. scHoLL 2,917,849.

United States Patent invention relates to improvements ina shock absorbing insle and arch cushion, and'mre particularly to' s uch a device'for disposition in an article of footwear"- beneath the plantar surface of the human foot, the invention being particularly designed to give support, protection, and cushioning effect to the weight carrying por'tiorisfof the foot, namely the tarsus and metatarsus,

yalthough the invention may have other uses and purposes as will be apparent to one skilled in the art.

I n the past, many and various types of cushion supports for the foot have been developed, ,but in Vrnost instances these devices were not asV easy to iit Vinto a shoe and retain theirlposition as is desired, were not designed to properly cushion as well as support the various parts of the foot, a'nd'did not properly provide relief for foot strain, fatigue and exhaustion by cushioning properly and substantially the'entire plantar surface of the foot.

With the foregoing in mind, it is an important object HCC sho'ck absorbing insole embodying initially separate and spaced individual supporting elements secured to an overlying cover sheet with an extension on that vcover sheet in the region of the metatarsal arch to bend upwardl against the upper of a shoe.

While some of the most salient features, characteristics and advantages of the instant invention have beenabove pointed out, others will become apparent in the following disclosures, taken in conjunction with the accompanying drawing, in which:

Figure 1 is a top plan viewof a shock absorbingl insole and arch cushion embodying features of the instant invention;

VFigure 2 is a bottom plan view ofthe structure of- Figure 1;

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

Figure 4 is an enlarged transverse.v vertical sectional View taken substantially as indicated by the line IV-IV of Figure 1.

As shown `on the drawings: A

While the'illustrated embodiment of the kinstant invention irs shown in the form of a shock absorbing insole and arch cushion device which extends from the rear o f the heel of the user, to a point just beyondthe `metatarsal arch with parts of the toes extending forwardly beyond the device to provide ample toe room within a shoe or the like, it is to be understood that certain features of the invention may well be incorporated in supporting and cushioning devices for disposition beneath the plantar surface of the human foot o-f various ofthe instant invention'to provide both a shock absorbng'and cushion supporting device Vshaped to give support and [cushioning effect, not only to'the bearing points of a normal foot, but also to theiparts of a foot between and around those bearing points.

"-Another object of the instant invention is the provision of a softyv'ery light, and airy or ventilated foot cushion which may readily be slipped into an article of footwear and effectively retain its original position against any tendency to shift. i

`Alsoan object of the instant invention isthe provision of Va'shock absorbing cushioning insole capable of providing added cushioning effect during walking by virtue ofthe porous quality of the insole and the pumping of ar'at each step.

'A'further feature of the instant invention resides' in the provision of a shock absorbing insole embodying added individual supporting elements at separate locations, the construction being such that there is no objectionable or irritating wrinkling orV buckling of the insoler during use.

Another feature of the instant invention resides in the provision of a shock absorbing insole embodying a number of initially separate pieces, all supporting pieces being secured to the cover member only of the insole, and a-separatefcushioning under layer being secured to the cover' only around the bounding margin or edge of the device,A but otherwise unsecured tothe cover or any of the separate supporting elements.

AStill a further feature of the instant invention resides iny 'theprovision of a shock absorbing insole carrying separate supporting elements therein which includes a cover layer, and an underlying cushioning bottom layer or sheet in addition to the separate supporting elements, with the supporting elements heat sealed to one of the layers and not to the other, certain of the heat seal seams providing a bending or hinge function whereby a portion of the@ device may be disposed at an angle to the other shapes in the event it is not desired to correct or support as many parts of the foot as the instant device is capable of supporting. However, the illustrated embodiment of the invention is designed not only to give support and cushioning effect to the weight carrying portions of the foot, namely the tarsus and metatarsus, `and thereby better balance the foot, but the invention also lends cushioning aid not only to the individual bearing points of the foot but the parts of the foot intermediate those bearing points.

With reference now to the drawings, it will be seen that'the illustrated embodiment includes a cover sheet 1 preferably providedwith numerous perforations throughout as indicated at 2. At one side of the cover, sheet 1, and preferably opposite the longitudinal arch of the'foot the cover is provided with an integral extension 3. A

rest without buckling or wrinkling in any of thestructure.

'ltis*also an object of this invention to provide a bottom sheet 4 of cushioning material underlies the entire cover 1 with the exception of the extension 3. This. ,l bottom cushioning sheet is preferably of a foam material having intercommunicating cells so as `to provide adequate ventilation and provide an added cushioning effect due to the pumping action caused by the application and release of pressure upon the device during walking. Such i intercommunicating cellular 'cushioning sheet coupled the cushion at each step.

Preferably the cover sheet 1 and the cushioning sheet 4 are made of thermoplastic material of the character 4that may readily be heat sealed. Various thermoplastics are suitable for this purpose. By way of example, 'however, and not by way of limitation, I maymention that a 4satisfactory substance for the thermoplastic foam boti tom sheet 4 is a vinyl foam made from a liquid composition. generically known as a plastisol. This plastisol may beexpanded by the use ofan inert gas or otherwise, and then cured in the expanded condition to provide a light weight structural material which is highly." flexible, highly resilient, possesses' great restorative propty erties, andwis provided with intercommuuicating cells. This plastisol may satisfactorily be a dispersion or suspension of polyvinyl chloride resin, or a copolymer in one' or more' plastisizers selected from a large number.

ofhigh lboiling esters, for example, such as dioctyl:

` The phthalate, dioctyl adipate, dicapryl phthalate, etc; top? cover sheet 1 is preferably a lm and may be made of the same material as the foam cushioning sheet, but ifso, the resins and plastisizers are charged into a Banbury milll and from there passed to a calender which rolls'- out thev nshed product, thereby making the top sh'cet'niorc. in the nature of an unsupported vinyl iilm. Obviously, the top sheet is far denser than the foam cushioning sheet. Y

A segment shaped piece 5l or" thermoplastic foam is preferably provided beneath the longitudinal arch of the foot,- and as seen in Figures l and 3, this segmentshaped piece of foam is preferably heat sealed, such as by high frequency electronic heat sealing, to the cover 1 only, alongl a curvate heat seal seam 6, and substantially longitudinalV heat seal seam 7. ln each instance, where a foam member is heat sealed to a lm member, the heat seal is preferably of such character that the foam layer will be provided with curvate edges as indicatedat 8 in Figure 3, whereby thereare no abrupt elevations in thetnished' device. n

A generally ovate metatarsal lift, which may satisfactorily'be a piece of thermoplastic foam 9, is Valso secured only to the cover 1 by means of a heat seal seam l() around the `bounding edge of the lift9. Prefeably this metatarsal lift is of such vsize that the rst land fifth metatarsal headsY will fall on opposite sidesof 'the lift, but rest upon the cover member above the underlying cushion sheet 4.

Beneath the extension 3, there is a small bottom piece 11 which may satisfactorily be of the same film as the cover. outer edge by a heat seal seam 12. Between the cover extension 3 and the under piece 11 is another cushion element 13 which may satisfactorily be of the same thermoplastic foam above described, and this piece of material is caught in the aforesaid heat sealed seam 12 at its outer bounding edge,rbu`t the inner bounding edge thereof is heat sealed' to the small underlying piece 11 only by a heat. seal `seam 14 which also connects the underlying piece 11 with the bottom cushion sheet 4 alongthe inner side ofthe extension.

The bottom cushion sheet 4 is secured to the cover only except for the seam 14 as above explained, around the' bounding edge of the device, and this also is prefera'blya heat sealV seam 15, but the bottom cushion layer is otherwise free from securement to the cover 1 andv to any of the added cushion lifts. As seen best. in Figure 3, the seam 4' along the inside of the extension isa composite seam connecting the under piece 11 with the'lift 13 and also lconnecting theV under piece 11 with thecushion bottom sheet 4, but preferably the lift 13 and the sheet 4 are not directly' connected to each other at this point.

Looking again'at Figure 3, it will be noted that 4the heat seal seams-7 and 1'4 conjointly provide a hinge effect,`whereby the extension including both the cover part 3, the under piece 11 and the lift 13 may readily be bentupwardly along the inside of the shoe upper, these two heat seal'seams conjointly'forming hinge means for that purpose.

lt'r'should also be especially noted that by virtue of theA bottom' cushion sheet 4 being free from theA other portions of' device except for the heat seal seams 14 and 15-,yrelative movement between the cover and the lifts,I and the bottom layer is? provided, so that during usethere is Ano objectionable or irritating wrinkling or buckling of they deviceat any place; Also, duringrus'e,

thetjntercommunicatingcells'in theub'ottomv'sheet 4' as This piece is heat sealed to the cover along its Well as the intercommunicating cells in the various lifts 5, 9 and 13 cause air to be pumped through the device and the perforations in the cover pass some of that pumped air s'o that the foot is not only adequately ventilated, but there is an added cushioning eifect by virtue of that air pumping.

Further, it will be readily understood that the device not only affords an adequate cushioning vbeneath the three bearing points of the foot, namely the os calcis, and the rst and ifth metatarsal heads, by virtue of the bottom sheet 4, but it also lendsa cushioning lift to the metatarsal arch and thel side of the foot adjacent that arch byy virtue of the added cushion lift 5 and the lift 13, and further adequately supports the metatarsal arch by virtue of the added cushion lift 9, whereby the device supports all parts of the foot intermediate the normal three bearing points, stabilizes the foot,` and willobviously greatly relieve foot strain, fatigue, and exhaustion. In' addition, Vit may be mentioned that the device is extremely light in weight, may be made in' anyV desiredv colors, and laundered whenever deemed necessary.

VIt will be understood that modifications and variationsV ingathermoplastic cover sheet, a thicker thermoplastic,

foam sheetunderlying said cover sheet, an added piece of thermoplastic foam positioned tounderlie the longitudin'al` arch' ofthe foot, and an added piece of thermo-Ii plastic foam positioned to support the metatarsal arch of the foot, said added pieces being secured to said coverl sheet, and said foam sheet being secured to said cover sheet at the bounding edges, a lateralv extension on said cover opposite the longitudinal arch supporting foam.

piece, a small thermoplastic bottom piece under said extension, and a foam piece in said extension joined to said extension and said bottom piece, and the inner edge of said bottom piece being joined to said foam sheet by a seam functioning also as a hinge to permit said extenf sion to readily bend up inside a shoe against the upper ofthe shoe.

2. In an' arch cushioning insole for a shoe, a cover sheet in the form of a thermoplastic film having a lateral extension in the region of the longitudinal arch, a small piece of thermoplastic lm underlying said extension, a

thermoplastic foam arch cushionv secured tosaid cover sheet inside said extension, a thermoplasticpfoan pad between the films of the extension and securedV thereto along the outer boundary of the extension, and lathermoy plastic foam sheet underlying said cover sheet. except for A secured to the underside of said cover, andf a bottoml cushion sheet `vsecuredai the bounding edge ofi the device to said cover and otherwise free of securement to4 said.

cover `and said cushion element, and said cover having a lateral extension in the region of the longitudinal arch, an extra sheet beneath said extension and secured atits outer margin to said cover, a cushion element between said extension and said extra sheet, and the inner edge of said extraV sheet being secured to bothrth'e last said cushionelement and saidv bottom cushioni sheet.

4. Ina cushion insole,.a cover' sheet havingalateral extensiony to turn upwardly against a shoeupper inlthe region ofA the. longitudinalV arch of the foot whenl the' insole Vis placed in a'shoe, an archsupporting' cushion underlying said'cover sheet and secured to said sheet by a hinge rseam defining the innerside of said extension,

a small. sheet underlyingY said extension and secured tov said' cover..sh erlet g:.tty the outer edge of said extensiom a.

layerA of `cushioning material between the cover extension' 'and said small sheet and secured to said small sheet in a hinge seam substantially in vertical alignment with the first said hinge seam, and a bottom layer of cushioning material underlying said cover and said arch supporting cushion inside said extension and secured to said cover along the bounding edge of the insole and to said small sheet along the inside of said extension.

References Cited in the flle of this patent UNITED STATES PATENTS 545,006 Baird Aug. 20, 1895 6 Carling June 18, 1918 Phelps July 16, 1918 Gash Apr. 1, 1924 Boos Nov. 8, 1949 Woodbury Jan. 17, 1950 Scholl Feb. 12, 1952 Scholl Nov. 10, 1953 OTHER REFERENCES 10 Modern Plastics Periodical, Plastic Digest, November 1954, pp. 106-108 and 214-216. (Copy in Div. 11.)

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