US1534919A - Shoe tread - Google Patents

Description

April 21, 1925. I 1,534,919

' L. B. CONANT I SHOE TREAD Original F1165 Nov. 17. 1920 ,FiyZ I F191 I I Q LeonB. Conant- Fly: 18 1 7777 J Patented Apr. 21, 1925 LEON B. CONANT, 0F CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO GEORGE W. CONANT, OF BRIDGEVVATER, MASSACHUSETTS.

SHOE TBEAD.

Application filed November 17, 1920, Serial No. 424,582.

To all whom it may concern.

Be it known that 1, Leon B. GONANT, a citizen of the United States, and a resident of Cambridge, in the county of Middlescn and Commonwealth of Massachusetts, have invented certain new and useful Improvements in Shoe Treads. of which the following is a full, clear, and exact specification.

This invention pertains to boots and shoes, and has for its object the effecting of improved means for connecting a tread. preferably of rubber composition, to the heel and also to the soles thereof. In accomplishing this, I prefer to form the heel or the sole of a shoe in two sections the outermost of which is termed the tread, and to con struct the upper section with holes into which projections from the tread, are molded therein when the heel or the sole is vulcanized.

In the drawings forming part of this specification, Fig. 1 is a face view of the tread of a heel. Fig. 2 is a face view of the upper portion of the heel. Fi 3 is a side view of the heel, showing a part of the shoe to which it is attached. Fig. 1 is a longitudinal central section of the same. Fig. 5 is a sectional view of the heel through the line 55 in Fig. 2. Fig. 6 is a sectional elevation of the upper member of the heel and a part of the shoe, showing a re-tread applied to the upper. Fig. 7 shows a rubber sole.

In the drawings, the reference numeral 1 designates the heel portion of a shoe sole, and 2 the upper portion of the heel designed to be permanently attached to the sole. This upper portion or base 2 is preferably formed with a large central cavity 3 whose marginal wall is substantially equidistant from the periphery of the base; and through the part of the latter between the periphery; and cavity 3 are formed numerous holes 4 preferably extending entirely through the base from its upper to its under surface.

The base 2 is composed of fibrous mate rial, preferably of leather-board, and is at tached to the heel portion of the shoe by means of nails 5 driven through it until their heads are flush with the surface thereof.

The tread 6 is preferably of rubber or rubber composition attached to the base 2 in the process of vulcanizing or molding the same. To do this, they are both introduced within a mold in the manner set forth in my companion application filed concurrently with Renewed August 29, 1924.

this application, one ofthe members of the mold being preferably provided with a projection nearly filling the cavity 3. Then by means of heat and pressure, the unvulcanized rubbed tread and the base 2 are molded together, the rubber flowing into and completely filling the holes a. The mold is preferably, also, adapted to form the nail holes 7 shown in F ig. 4. through which nails 5 can be driven to their attaching position above described. When the molding process is completed, the projections or plugs 9 consisting of rubber forced into the holes 4:, will firmly bind the two members together. beide the fairly stron adherence between the other contacting surfaces of the same.

The part of the mold which enters the cavity 3 being made substantially smaller than the latter in order to allow for unimpeded entrance therein, a layer of rubber will adhere to the margin of the cavity, as shown. in Figs. 4 and 5. Such part is made to extend through such cavity so that the tread will preferably not reach into the cavity but leave it hollow. The purpose of this is to provide means for the re-tread, after the original tread has become badly worn.

The upper member 2 and the tread 6 having been molded together as above described, the same is attached to the boot or shoe sole 1 by the nails 5, and the whole is ready for use, after suitable surface-finishing. lVhen. new, the tread is worn down by use until the upper member 2 is nearly reached, either the wearer or his cobbler can strip the tread away from the member 2, the projections tearing away from the tread, and the adhesion between the surfaces of the member 2 and tread 6 being overcome with comparative ease. For applying a new tread, a retread 10 is provided which has an integral projection 11 made dove-tail in form to fit the corresponding dove-tail shape of the cavity 3. This re-tread is molded in a manner to convex its tread surface and to concave its upper surfaces, thereby so diminishing the area of the projection 11 as to enable it to be readily introduced in the cavity 3. Then a nail or two 12 is driven through the re-tread into engagement with the sole 1, thereby flattening the same, a washer 13 being imbedded in the re-tread in a well-known way, as shown in Fi 6.

Thus attached to tie member 2, the engagement of the projection 11 and cavity 3 serves to hold the re-tread in place so that it can not twist and turn, and the dove-tail arrange-mentcombined with the nail 12 keeps the re-tread from pulling away from the member 2. It is the longitudinal displacement of the re-tread, however, which needs to be most strongly guarded against, and this is done by the large central projection 11.

Among other great advantages of this, whether the heel or sole, but especially of the. heel, is that it can be manufactured complete in itself and afterward attached to the shoe, thereby reducing the handling of parts to a minimum and saving in cost. Another important feature is found in the saving of material, since the upper member be main .ctured from scrap leather or other less expensive fibrous material.

in Fig. 7 is illustrated a shoe sole wherein a layer of fibrous material 16 is formed with holes into which a rubber composition 1? is forced in molding the same together, the projectionsylS thus impressed into the per- 9 ca I forated fibrous sheet serving to bind the tread 1T securely to the fibrous sheet, and still permitting the tread to be stripped therefrom by the latters tearing away from the projections. The fibrous layer is at tached to the sole 1 in any well known way.

3y having the base 2 composed of a plurality of lifts of fibrous material having holes, when the lifts are capped as shown in the drawings, by the application of presure thereto in the mold, the axes of the perforations f in the several lifts are canted, and this canting, together with the shifting of the lifts into their cupped positions, provides a stepped or staggered arrangement in the perforations, and consequently to the rubber forced therein.

Furthermore, inasmuch as the base as a whole receives the above described cupping, the attached face of the rubber treao is correspondingly cupped by the convex face of the lowermost lift. The holes or perforations t will thus receive a zig-zag contour, and the rubber plugs 91 molded therein will receive a correspondingly irregular form. Consequently, these plugs 9 will not be re tained within the holes a by surface adherence alone, but by the shoulders produced by the displacement, and it will be practically impossible to withdraw the plugs when the tread 6 is stripped from the base 2, but the plugs will be torn away from the tread, leaving the exposed surface of the base cornparatively smooth. apply the re-tread 10 thereto, as well as the more strongly confining the tread 6 to the base 2 during use.

It is to be observed that by thus curving the lifts composing the base 2, the central portion of the tread 1 is rendered correspondingly thinner than the marginal portions thereof, inasmuch as the upper surface of the tread is concave and its under surface is flat. This reduces the amount of rubber required for the heel without diminishing its resilience and wearing-life. This is evident when it is noted that in walking it is always an edge of the heel which first strikes the pavement. Consequently, the marginal portions of the heels are the ones which should contain the maximui'n amount of rubber. In other words, when a heel has become badly worn, it always presents a rounded face, either toward the right or the left or rearward, and approximately concentric thereat with the cupped upper surface. Hence the thinning of the central section'of the rubber tread doesnot rob the same of any needed material, although saving a substantial amount thereby in the manufacture of heels.

Further, since the rubber is more expenconsisting of a plurality of substantially duphcate perforate layers containing pro-- jections integral with the rubber lower part, said perforations and the projections therein being staggered.

In testimony that I claim the foregoing invention, I have hereunto set my hand this th day of November, 1920.

LEON B. CONANT.

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