US 3253601 A
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Description (OCR text may contain errors)
May 31, 1966 w. M. scHoLL 3,253,601'
CONFORMING FOOT CUSHIONING DEVICE FOR FOOTWEAR Filed Sept. 6, 1965 2 Sheets-Sheet 1 f nunca an nenn Wfl-Quang.-
.nro-o INVENTOR. WILLIAM M, SCHOLL 5 F195 WA4 ATTORNEY May 31, 196e w. M. SCHOLL 3,253,601
CONFORMING FOOT CUSHIONING DEVICE FOR FOOTWEAR Filed Sept. 6, 1963 2 Sheets-Sheet 2 ATTOR United States Patent O 3,253,601 CONFORMING FOOT CUSHIONING DEVICE FOR FOOTWEAR William M. Scholl, 213 W. Schiller St., Chicago, Ill. Filed Sept. 6, 1963, Ser. No. 307,250 4 Claims. (Cl. 12S-594) This invention relates to improvements in a self-conforming foot cushioning device for footwear, and more particularly to a cushioning device for insertion in an article of footwear and which may -be made as a partial or full insole, heel seat, rnetatarsal arch lift, or other shapes and sizes, and which may be provided wherever desired with additional thicknesses or lifts, all as will be apparent to one skilled in the art.
In the past, many and various foot cushioning devices for insertion in an article of footwear have been developed. However, such cushioning devices heretofore known, while compressing under body weight, would almost irnmediately assume or recover to original sh-ape upon removal of body weight or pressure; In some instances, of course, alleged cushioning devices heretofore known, made of relatively poor material, would ultimately compact and become hard, although they might have a higher recovery factor at the beginning of use. These formerly known cushioning devices would respond to pressure by way of a general depression which, if under the heel, would immediately recover to original shape while the foot rested upon the toes during a step. There would be no lag in recovery, and a general impression would result next time. It was impossible for these devices to self-conform So as to intimately fit around a projection' or excrescence on the foot and maintain such t for a time after pressure was removed. Heretofore, the only way of obtaining an intimate tit would be to specically mold a foot supporting device to 4an individual foot, and in most instances then no cushioning effect was obtained.
With the foregoing in mind, it is an important object of the instant invention `to provide a foot cushioning de-A vice for insertion in an article of footwear which is self- Conforming to intimately fit irregular or abnormal surface points on the foot such as enlarged joints, sensitive sesamoid bones, hammer or contracted toes, corns or calluses, plantar warts, depressed metatarsal heads, -among others.
It is also an important object of this invention to provide a foot cushioning device for insertion in an article of footwear which always maintains its cushioning property, and yet is self-conforming to mold itself intimately in keeping with the surface of the foot and by virtue of its slow recovery, maintain its molded shape for a considerable time after foot pressure has been removed.
A further object of this invention is the provision ofa foot cushioning device for insertion in an article of footwear and which is self-conforming to intimately t and shape itself to the exact contour of an individual foot, and which is so slow in recovering that if the device is regularly utilized it will recover its original shape only partially overnight, So that on the following day the foot is received rather intimately by the device in a manner extremely comfortable and helpful to the user.
Also an object of this invention is the provision of a foot cushioning device for insertion in an article of footwear, which device embodies a thermoplastic foam cushioning material that is of closed cell structure, substantially non-porous and air impervious, and which molds itself to the exact shape of a particular foot and retains such molded shape for a considerable time after foot pressure is removed while yet retaining its cushioning property.
Still a further feature of this invention is the provision of a self-conforming and moldable foot cushioning device which may economically be made in various shapes and ice sizes and which almost immediately conforms to the exact shape of the part of the foot it contacts.
While some of the more salient features, characteristics and advantages of the instant invention have lbeen above pointed out, others will tbecome apparent from the following disclosures, taken in conjunction withthe accompanying drawings, in which:
FIGURE@ is atop plan view of a full insole embodying principles of the instant invention;
FIGURE 2 is a vbottom plan view of the structure of FIGURE 1, in reverse position from heel to toe;
FIGURE 3 is a top plan view, with parts broken away to show parts therebeneath, of an insole of slightly different construction from that of FIGURES 1 and 2;
FIGURE 4 is a greatly enlarged diagrammatic vertical sectional view, as may fbe taken anywhere through the insole of FIG. l, indicating the action of the material utilized;
FIGURE 5 is a greatly enlarged transverse vertical sectional View taken substantially as indicated by `the line V-V of FIGURE 3, looking in the direction of lthe arrows;
FIGURE 6 is a plan view of a half insole to underlie the forward part of the foot, also embodying principles of the instant invention;
FIGURE 7 is a longitudinal vertical sectional view through the structure of FIGURE 6 taken substantially as indicated by the line VII- VII of FIGURE 6;
FIGURE 8 is a plan view of a three-quarter insole containing -added lifts for the arches of the foot and embodying principles of this invention;
FIGURE 9 is a bottom plan view of the structure of FIGURE 8; and
FIGURE l0 is an enlarged transverse vertical sectional View taken substantially as indicated by the line X-X of FIGURE 8.
As shown on the drawings As stated above, the instant invention may Abe made in various shapes and sizes for various purposes, and to illustrate this `particular feature several modifications have been shown `by way of example, but not by way of limitation. Devices embodying the instant invention may be freely inserted in an article of footwear or cementitiously or otherwise secured in position in an article of footwear, as may be desired.
The first illustrated embodiment of the instant invention comprises a cover sheet 1 which is preferably a thermoplastic film or sheet, such as an acetate or polyvinyl chloride lrn. This cover 1 may be provided with numerous perforations 2 therein, if so desired. Beneath the cover 1 there is a much thicker layer 3 `of thermoplastic foam having a low recovery factor. The two layers are joined together by a fine line heat seal seam 4 which also defines the bounding edge of the insole. The insole is preferably placed in an article of footwear with the foam layer 3 downward against the built-in insole of the footwear.
The second illustrated embodiment of the instant invention, seen in FIGURES 3 and 5 includes the same cover layer 1, with perforations 2 if desired, and the same thicker foam layer 3, as above described. In addition a bottom cover 5, preferably of the same material as the cover 1 has been added, and all three layers are joined together by a ne line heat seal seam 6 as seen more clearly in FIGURE 5. The bottom cover S is preferably imperforate, and the addition of this cover provides a more durable cushioning insole. Such added durability may be desired where the insole is worn in work shoes or where there is frequently a probability of sand or other abrasive entering the footwear while in use.
In FIGURES 6 and 7 I Ihave illustrated the instant invention in the form of a half insole to underlie the forward portion of the foot when placed in an article of footwear. In this instance the structure embodies a cover layer 7, with or without numerous apertures 8 therein, and beneath this is a thicker layer 9 of cushioning foam, both layers being of the same material as utilized in the previously described embodiments. The two layers are joined together by a ne line heat seal seam 10 extending around the bounding edge of the device.
' Another example of the instant invention is shown in FIGURES 8, 9 and 10. In this instance, a cover layer 11, with or without apertures 12 therein, and of the same rnaterial as the cover 1 above described is included, and to the underside of that cover layer a metatarsal lift 13 is secured by a heat seal seam 14 around the lift. This lift is made of the same thermoplastic foam material lhaving a low recovery factor, as above mentioned. A similar foam lift 15 for the longitudinal arch is also secured to the underside of the cover 11 by a heat seal seam 16 around the bounding edge of the lift. These two lifts are secured to the cover 11 only. Beneath the cover with the attached lifts is a full layer 17 of the same thermoplastic foam which is of the same area as the cover. Beneath the foam layer 17 is another cover layer 1S with its center portion removed as indicated at 19, so that this cover layer merely forms a protective marginal portion 20 along the partial insole. The two cover layers 11 and 18 and the overall foam layer 17 are secured together by a heat seal seam 21 and the foam ltyer 17 and bottom cover 18 are also secured together by a heat seal seam 22, which is directly opposite a portionof the aforesaid heat seal seam 16 and along with that portion of the seam 16 functions a 4hinge so that the side tab of the device, `generally indicated by numeral 23, may turn upwardly inside the article of footwear adjacent the inner longitudinal arch of the foot. When this particular form of device is in use, added support is given boththe longitudinal and metatarsal arches of the foot. The marginal part 20 of the bottom cover 18 protects the edge of the foam layer 17 from abrasion.
The illustrated embodiments of the instant invention can be economically produced on an electronic or ultra high frequency heat sealing press. It is a simple expedient to place the various layers used on the press, bring down a die, provide an almost instantaneous charge of high frequency current, and the necessary heat seal seams are established, the particular seam defining the outline of the device being also, by virtue of proper die construction, capable of establishing a tear seal at the same time wherebythe stock waste is easily removed.
The thermoplastic foam cushioning means utilized in any embodiment of the instant invention is preferably from the `group of foams including polyvinyl chloride, isocyanate or polyester, polyurethane, and similar foams. Such foams can be porous, non-porous, air impervious, air pervious, their density varied, and various other physical properties depending upon the particular formulasused and the control exercised during the making of the foams. Most of these foams have a high recovery factor, returning to original shape almost immediately when pressure is removed. Wit-h the present invention, however, conformation of the foam intimately to the contour of a particular foot when .foot pressure is applied, and slow recovery from the conformed shape when pressure is removed, are important desiderata.
By way of spe-cinc example, one such material, proven highly satisfactory both in tests and in actual usage, is what might be termed a fully cured, closed cell, homopolymer polyvinyl chloride foam having a skin on each side thereof, indicated at 24 and 25 in FIGURE 4, which adds strength and enhances slow recovery, since the skin substantially seals out air. This foam preferably has closed cells `within the range of 70% to 100%. Accordingly, the foam is substantially non-porous and air impervious. The density of the foam may be approximately l0 lbs. per cubic foot.
While the foam may be made in any desired thickness, for most embodiments of the instant invention, a thickness of .125 inch is satisfactory. Foam of such thickness was placed under what might be termed 50% compression set tests. In such a test the foam is placed for 22 hours at 158 F. under a load sufficient to reduce the foam thickness to 50% of its original thickness. At the end of 22 hours the load was taken off andthe material allowed to recover for 2 hours at 158 F. and then brought to room temperature before recovery was measured. The average for a Vseries of such tests was 42% set, and 58% recovery for the two hour period. In use at room or body temperatures, recovery is even slower.
When in use the foam is highly eicient in its action. When the insole of FIGURES'l and 2, for example, is pla-ced in an article of footwear, and body weight placed thereon, the foam layer almost instantaneously conforms itself to the plantar pattern of the individual foot. This is indicated in FIGURE 1 in dotted line, the pattern being generally indicated by numeral 26. It will be noted that every pressure point provides a corresponding indentation and by virtue of the slow recovery property of the foam the conformed shape assumed by the foam will be extremely intimate to the shape of the particular foot. Thus, an elevation will occur beneath the sulci of the toes as indicated at 27 to such an extent that the toes will automatically grip that elevation during walking and thus benecial exercise also is provided for the foot. At 28 I have indicated a deeper indentation which would be caused by a sesarnoid or supernumerary bone occurring under the first metatarsal head, and the fit around such an afiction will be intimate with the cushioning foam entirely around the abnormal point so as to effect almost instantaneous relief from pain. While the foam may be said to set in accordance with the plantar surface of the foot, it nevertheless always' retains a cushioning effect upon the foot. For example, as indicated in FIGURE 4, the foam layer 3 in the right-hand side of the gure is shown -at its normal height with the closed gas filled cells generally globular, but under a pressure point of the foot the foam layer would decrease in thi-ckness and the closed cells flatten out as indicated at 3a in the lefthand side of the figure. However, there is always sufcient foam and compressed gas in the flattened cells beneath any pressure point to provide an ample cushion.
Should the insole be worn regularly, after a relatively short time the foam will set to such an extent that it will not recover suiciently to eliminate the impression therein overnight. put on the following morning at least a goodly part, exceeding one-third, of the impression remains and the foot is immediately comfortable.
From the foregoing, it is apparent that I have provided a foot cushioning device for insertion in an article of footwear which is self-conforming and almost immediately assumes an intimate fit for the plantar surface of an individual foot, and the pattern assumed bythe foam remains for a considerable time after foot pressure is removed, and the foot is cushioned at all times during use.
It will be understood that modifications and variations may be effected without departing from the scope of the novel-concepts of the present invention.
I claim as my invention:
1.- A foot cushioning device for placement in contact with a foot in an article of footwear and embodying:
a layer of substantial thickness of thermoplastic foam cushioning material having 70% to 100% gas lled closed cells throughout and an outer impervious skin,
said layer conforming under foot pressure to the surface of a foot and being possessed of a low recovery factor of less than 70% in a two hour interval after removal of foot pressure.
Consequently when the footwear isv 2. A foot cushioning device as defined in claim 1 in which said material is homopolymer polyvinyl chlorideA References Cited bythe Examiner UNITED STATES PATENTS 7/1942 Daniels 12S-595 X 3/1951 Lavinthal 128--595 6 2,626,886 1/1953 Scholl 12S-595 X 2,760,281 8/1956 Cosin 12S-595 2,961,780 11/1960 McManus 12S-586 3,121,430 2/1964 OReilly 128-595 3,135,265 2/1964 Holzman 128-619 References Cited by the Applicant UNITED STATES PATENTS 2,504,704- 4/1950 Lee. 2,878,153 3/ 1959 Hacklander. 2,878,593 3/1959' Lockridge. 2,917,846 12/1959 Scholl. 2,953,130 9/1960 Scholl. 3,134,381 5/1964 Scholl. 3,170,250 2/1965 Scholl.
RICHARD A. GAUDET, Primary Examiner.