US2798312A - Plastic shoe unit - Google Patents

Description

F. A. MULLER PLASTIC SHOE UNIT AFiled may ze, 1954 July 9, 1957 The present invention relates to vshoes formen, women and children and, more particularly, to a basic unit thereof to which may be attached a yaricty of types of uppers structures for forming a variety-of styles.

A general object of the present inventionis to provide such a basic unit as a one-piece'molded plastic structure which can be readily and economically Vmanufactured in mass production of a plurality of sizes to which diiferent types of uppers may be attached in asimple manner for producing an unusuallylarge'variety of styles, -allowing retailing at very low prices of shoeshaving many advantages over more expensiyely produced leather shoes, such as unusual Yfit-assuringf m'airinrurn comfort, shaperetention, water-proofness, electrical hon-conductivity, long-lastingV attractive finish, immunity toV attack Vby mold and destructive bacteria insuring longservice life, long wearing quality and scui-proofness, andother ldesirable features hereinafter made apparent. r

A more speciiicobjectof the present invention is to provide such a molded plastic basic-shoe unit whichrmay be rapidly produced by molding under heat 4and pressure as a nished product requiring no further finishing or work thereon other than simple procedures ofv attaching upper means thereto, such unit comprising as integral portions a heel, counter, shank, and forepart in thejform of a tread sole portion anked `byvan upstanding forepart foxing merged with the counter.

A further object of vthe -presentf invention is to provide an embodiment of the footwear of the-present invention which may be readily'tand cheaply made land which assures ecient service.

Other objects of the invention xwill -in -part .be obvious and will in part appearhereinafter.

The invention raccordingly comprises-,an article of manufacture possessing the features,4 properties, .and the relation of elements'whichuwillwbe `exemplified inthe article hereinafter described, and the scope .ofY theiinvention Will be indicated in the claim.

For a fuller understanding of the naturevand objects of the invention reference should be had tofthe `following detailed description'taken in connectiornwith the accompanying drawing, inwhich:

Fig. 1 isa longitudinal sectionaLelevation of anembodiment of i, theplastic shoe unitof the presentinvention anda mold forforming it,- the,lattervbeing illustrated in diagrammatic formas employedginrnoldingthe shoe unit;

Fig. 2 is an,elevationalperspcctivepffthelrighthoe unit of the ltype depicted i,nEig. 11, ,as viewedfrom the front; i

Fig. 3 is a,longitudinal,seCtQnaleleuationpffthe shoe .unit of Fs- .2, vshown /withbodywofffillerrmaterialf1ocated in the heel well `and an vinsole mounted linthe junit; and

Fis- 4 iS a rerspectire view. ofthe left Shoeunitof ,the

ited States Patent type shown in Fig. 1, as viewed from the s ide and below, )illustrating in dotted lines a typical upper which may be attached thereto yfor completion of a certain style of shoe.

Referring to the drawing,` inl which like numerals identify similar parts throughout, it will be seen that an embodiment ofthe present invention comprises va `molded plastic basic shoe unit 10 illustrated in Fig. 1 as being molded with the use of a moldk apparatus 11, which may consist of a female dielZTand a male die.13. Preferably, the plasticshoe unit 10 is to be molded from asuitable synthetic polymer composition which may assure/to Athe molded unit leather-like characteristics and, more specically, those indicated herein. `Such plastic ,material maybe as uitable polyvinyl chloride composition plasticized, if desired, in which may be incorporated, if wished, any Ysuitable coloring and/or opaquing material. 'If the -selected lplastic material is of the thermoplastic type, the molding apparatus will, of course, be so constructed as to apply the necessary shaping pressure,andplasticizing heat, and -may include cooling 4means in `accordance with Ithe teachings'of the-molding art, thel specific techniques of which form no part of the present invention.

-Thermale and female dies'12 and 13 may be made of iineftool steel with the-surfaces 14-and 15 defining the mold cavity preferablybeing suitablyplated, such as with chromium, preferably buifed to a smoothy nish of `high polish to-give to `the molded shoe unit 10 ai highly pol- .ished and iinished surface which may Abesimilar to thatof 'line -tpatent leather or high-grade kid or calf skin. -Such a -molded shoe `unit'ltl may require 45 seconds to 2.1/2 min- `utes to produce, depending upon the characteristicsof the particular plasticv composition used Vandwthe cooling factor, i. e. a period of time suiicient to assure .under icertain conditions solidiiication to lpermit the molded unit .to-be stripped fromA the female Ydie cavity. :The molded plasticshoe unit 10, in the-formfillustrated in the Ldrawing, consists of a waterproofgunitary structure of plastic Vmaterial having comfort-contributing but limited rilexibility and some elasticity `to be 1it-adaptable,and.self shape-retaining -without discomfort to the wearer :while having suicientstiifness to give adequate support, and is pf good wearing vquality ,and Asubstantially ,scut-proof. 4T his basic shoe unit10consistsof a heel portion-,16, ,a full counter portion `17, a forepart-` tread sole portion 118, v a shank portion` 19, and a vamp foXingZ.

`The heel portionf16 of the illustrated embodiment may include a substantially flat bottom `7.1 substantially D- shapedin outline; a transverse, upwardly-extending breast 252.; and.v side walls 23,7, preferably `ofconventionalshape, and together ,defining .an open top.well24,. as shown.

The full counter 17 issuperposed abovetheqheelside .walls,234 and is in the formcof4 twol integral shaped quarters, i. e., i the v inside quarter 25 and l the outside quarter `2,6, which, as will be bestseenfrom Fig. 2, aref-,noticeably curved inwardly'or-,concaved soasgto attain a desiredsnug iit to the sides -of a persons heel, whichv is so difficult to provide in leather footwear. Such shaping of the quarters'ZS and 26 secures a snug fit whichfkeepsv the foottfrom sliding lup and down within the counter and assures maximum comfort. Since .the plastic material is flexible and elastic, the counter.17 is-.automatically adaptable in shapefto the particular yshape of-any certain persons heel offnormalcontour andis notvsubject'to the misshaping `characteristic lof leather shoes which mayfresult from dampening by perspiration or water and then drying to a distorted set.

"The forepart tread s olev portion "18 and theY shank portion 19 connecting it to the heel breast 22 preferably are of conventional shape to assure maximum comfort to a persons foot with the particular height of heel 16 employed in the embodiment illustrated by way of example. If desired the shank portion 19 may be strengthened by any suitable insert which may be interposed thereon beneath an insole or molded into the shank portion to give better support to a persons arch. A Y

The vamp foxing 20 comprisesan upstanding wall extending upwardly, preferably continuously, along the margins of the forepart tread portion 1S and the shank portion 19 to an appreciable height to form the vamp side walls, and preferably to a height less than the thickness of the forepart of an average persons normal foot,

e. g., the ball of his foot and toes. Vamp foxing 20 merges with the concaved quarters 2S and 26 to form forward extensions thereof. The upper edge 27 of the vamp foxing 20 curves upwardly tosmooth mergence with the upper edge 28 of the counter portion 17, as shown in the drawing. It will thus be seen that the por- ,tions of the top edge of the continuous upstanding wall provided by the counter 17 and vamp foxing 20 which extend across each of quarters 25 and 26 and along the shank portion 19 to the portions of the foxing along the tread sole portion 18 are of smooth, relatively llat ogee shape.

As proposed in Fig. 3, the heel well 24 is llled with a body 29 of suitable filler material, such as cork, soft or sponge rubber, or other light-weight resilient or elastic substance, so as to minimize the shock to a persons body when the heel strikes the ground during striding. It has been found that such a lilled heel transmits much less shock to a persons body than does a solid heel, even when the latter is provided with elastic lifts. Preferably, the basic unit is provided with a suitable insole 30, the back portion of which overlays and covers the iller body 29; and, if desired, the tread and shank portions 18 and 19 are shaped externally to simulate the edges of an outsole. The elasticity of the molded unit permits ready stripping from the mold cavity even though there be undercut areas.

The basic shoe unit 10 may be employed in the construction of a vast variety of styles of footwear since uppers of various types may be readily attached to and mounted thereon. For example, as illustrated in Fig. 4, such basic shoe unit 10 of the illustrated shape may be readily converted into a sport oxford by perforating the upper margins of the vamp foxing and fastening thereto by laces, such as is illustrated in dotted lines at 31, an attractive forepart or vamp upper 32, illustrated in dotdash lines. From a stock of such molded plastic basic units 10 one can create and produce literally hundreds of different styles of shoes. A particular model of basic unit 10 in both rights and lefts may be stocked by a manufacturer in some ifty-sx different variations in sizes and widths, which will selectively t the feet of average people and, of course, diiferent models of such basic units may be stocked in such variations to multiply the number of possible styles, such as those of a sport line, those for street wear, pumps, sandals, etc. To such basic units may be attached in simple manner a variety of types of cross straps, perforate and imperforate vamp uppers and toeless foreparts, as well as oxford upper portions, uppers for high-cut boots, opera pumps, etc., and by any suitable decorative means, such as lacings, eyelets, stitching and the like. Such molded plastic basic shoe units, of course, may also be produced for womens, mens and childrens footwear as well as for orthopedic and corrective shoes and even for employment in the construction of medical prescription shoes where fit must be exact with respect to ill-shapen and deformed-feet. lines of shoes and such special footwear may be produced with the employment of basic shoe units of the present invention at a cost much cheaper than that required by shoe manufacturers of similar footwear from leather and Such standard A 4 other materials standard in the art as employed in accordance with standard practices. Despite such economy permitting such shoes to be marketed at much cheaper retail prices, the resultant shoes have many advantages over leather footwear in that the molding thereof provides an unusually attractive nish without requiring tedious and costly finishing operations while assuring that the resulting footwear will be waterproof with respect to wet surfaces over which one strides, without necessarily preventing free air circulation since suitable provision therefor may be made in the uppers attached thereto. Footwear made with the employment of basic units of the present invention also is sturdy and may be substantially sculf-proof by the employment of suitable tough plastic material as well as long-lived to outwear similar models made from leather. Also, by-beng-waterproof, such shoeV bottoms also assure elimination Vof accident hazards since the plastic material may be electrically non-conductive and the soles thereof may be of a non-slip quality, minimizing the hazard of falling. Such basic shoe units also assure against destruction by mold and bacteria, which is of particular concern in damp climates and tropical countries.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efciently attained and, since certain changes may be made in the above article without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claim is intended to cover all of the generic and specic features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what l claim as new and desire to secure by Letters Patent is:

A molded plastic, basic shoe unit comprising integral shoebottom portions of waterproof, exible and elastic plastic material of good wearing quality and sutiicient stiffness to tend to retain its shape in use; the integral portions comprising, in combination; a relatively at, shaped forepart tread sole portion; a shaped, arched shank portion extending rearwardly and upwardly from the back of said tread sole portion and merging smoothly therewith; a relatively low, hollow heel portion integrally connected to the back end of said shank portion and having a relatively wide, substantiatlly flat bottom of D- shaped outline, a transverse, relatively low breast extending upwardly from and integral with the front edge of said heel bottom, and relatively low sidewalls extending upwardly from and integral with the remaining marginal edges of said heel bottom with said sidewalls being smoothly curved about the rear side of said heel portion, said heel bottom, heel breast and heel sidewalls together defining an open top well; an upwardly-extending full counter superposed above the heel sidewalls and constituting two integral, complementary, full quarters with each of the latter concaved appreciably inwardly on its side face for snug fit to the inner and outer sides of a persons heel; and a vamp foxing consisting of a continuous wall upstanding from and integral with the marginal edges of said tread sole and shank portions; the height of said foxing wall alongthe edges of said tread sole portion being appreciably less than the thickness of an average persons normal foot with the top edge of said foxing along the edges of said forepart tread sole portion being at approximately the same elevation at all points, the top edge of said foxing along the edges of said `shank portion curving gradually upwardly back toward the top edges of said quarters to smooth mergence therewith with gradual progressive increase of the height of said foxing wall along said shank portion, said counter and said foxing vwall together providing a continuous upstanding 'wall along said tread sole, shank rand'Y heel portions with the top edge thereof across each quarter and along the shank portion to the foxing along the tread sole portion being of smooth, relatively at ogee shape, said foxing wall being adapted to have attached thereto vamp upper means to provide a full shoe; said shoe unit having a separate body of relatively light-Weight, shock-absorbing filler material substantially lling the heel well, and an insole overlying the upper surface of said tread sole and shank portions and said body of ller material.

References Cited in the le of this patent UNITED STATES PATENTS 114,340 Prusha et al. May 2, 1871 466,297 Cross Dec. 29, 1891 2,063,227 Calvin Dec. 8, 1936 2,065,856 Grover Dec. 29, 1936 2,093,908 Dodge Sept. 21, 1937 2,349,374 Pym M-ay 23, 1944 FOREIGN PATENTS 757,922 France Oct. 3, 1933

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