US1735369A - Composite-rubber heel - Google Patents

Description

Nov. 12, 1929. WILLIS 1,735,369

COMPOSITE RUBBER HEEL Filed July 5, 1928 14 v1/ z QZZflWZW 1 %1 m# VMZQ Patented Nov. 12, 1929 UNITED STATES,

PATENT OFFICE GLENN H. WILLIS, OF AKRON, OHIO, ASSIGNOR TO JOHN L. SNYDER, OF AKRON, OHIO COMPOSITE-RUBBER HEEL Application filed July 5, 1928. Serial in. 290,309.

This invention relates to rubber heels of the type employing a seating layer vulcanized to the heel body and strengthened with an intermixture of reinforcing material.

The use of embedded metallic washers for retaining the nail heads has heretofore been nearly universal, although inserts of wood have lately been used to some extent, thereby reducing the labor and material cost but giving a less flexible and resilient heel.

The object of my invention is to provide a heel of relatively-high flexibility and resiliency without the use of metallic washers and at a reduced labor cost. To this end I employ an attaching plug or layer inseparably bonded by vulcanization to the heel body, said layer being of leathery firmness, that is, sufficiently hard to retain the nail heads and counteract the spreading tendency of the softer rubber of said heel body, but also possessing some resiliency which contributes to the cushioning properties and enough fiexibility to produce a tight seating of the heel, especially at the edges.

I have found that these characteristics are obtained by incorporating in the rubber compound of the attaching plug or layer a reinforcement of grain hulls, the preferred ma terial being oat hulls.

Of the accompanying drawings:

Fig. 1 is a top plan view of a rubber heel embodying my invention.

Fig. 2 is a perspective view of the attaching plug or layer. a

Fig. 3 is a sectional view of a portion of a heel'mold containing the heels, which are shown in transverse section.

In the drawings, 10 is the resilient heel body composed of suitable rubber compound such as a good reclaimed rubber, with or without new rubber, and containing the usual pigments, sulphurfor vulcanization and accelerator.

The attaching layer is a shallow inlay or plug 11 composed of rubber compound of about the same (tlallty as the body compound, or it may be a c a reinforcement consisting of grain hulls 12 distributed throughout its mass. The best 50 hulls I have found for the purpose are oat eaper quality, together with hulls which are relatively cheap and of high reinforcing value. Since ,they replace a con- The proportion of oat hulls employed is approximately thirty percent of the total weight of the stock in the attaching layer, but this proportion may be considerably varied. The rubber stock in the layer 11 is made relatively soft or sappy by, the introduction of five to six percent of a flux or softener such as cottonseed oil, palm oil or a suitable combination of vegetable and mineral oils in order to facilitate the distribution of the hulls throughout the plastic rubber. Milling is preferably performed on even-speed rolls having an open setting to avoid a bank and the hulls are fed between the rolls into the sheet which follows one of the rolls, the opening being increased as the volume builds up.

When a homogeneous mixture has been obtained, the compound is run into a sheet of the desired thickness and flat blanks or plugs 11 of the shape shown in Fig. 2 are died out of said sheet. For each heel, one of these plugs is located in the cavity of a vulcanizing mold 13 to forman inlay on the attaching face of the heel and is retained in proper p osition by pins 14 on the lower mold plate.

he body plug, the mold is then closed and the heel vulcanized, both body rubber and plug being completely cured in the sameperiod of time.

The labor cost for making heels with these rubber being placed against the attaching layers is less than for the common embedded washers and the reto spread substan around the edges is insured When the heel is nailed in place. The firmness oft-his inla-y resists the tendency of the softer body rubber tially after the attachment has been efiected.

The drawing illustrates a preferred form and arrangement of attaching layer reinforced as described but the details can be varied Without departing from my invention. This idea may also, if desired, be utilized for attaching rubber soles to shoes.

I claim:

1. A composite, vulcanized rubber shoe tread which is flexible and resilient throughout, said tread comprising a rubber cushion Wearing body, and an attaching layer of leathery firmness integrally vulcanized to said cushion body and formed of rubber intermixed With grain hulls, said layer being adapted to retain nail heads and resists the lateral spreading tendency of the cushion body.

2. A composite, vulcanized rubber heel comprising a rubber cushion body, and a flexible, resilient, attaching layer integrally united Wit-h and inlaid in the seating face of said body, said layer being composed of rub ber compound containing grain hulls having substantially thestifiness of oat hulls.

3. A composite, vulcanized rubber heel comprising a rubber cushion body, and a flexible, resilient, attaching layer integrally united With and inlaid in the seatin face of said body, said layer being composed of rubber compound containing a minor proportion of oat hulls.

In Witness whereof I have hereunto set my hand this 29th day of June, 1928. I GLENN H, LIS.

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