Detachable tread devices for automobile tires

Claim 1

A detachable tread device to improve traction of automobile tires, the device being adapted to be secured to the tires, the tires having a tread face adapted to be run on a road surface, the tread device including: a. a flexible base having upper and lower surfaces, the base having a length greater than that required to encircle the tread face of the tire, b. projecting means extending from the upper surface of the base the projecting means being adapted to improve traction of the tire, c. suction means extending from the lower surface of the base, the suction means being adapted by deformation to be brought into operative engagement, with and to grip, the tread face of the tire so as releasably to secure the tread device to the tire, d. the flexible base has opposing end portions and a length sufficient to produce at a join a controlled overlap of the end portions, one particular end portion having tapering means to provide a smooth join so that an acceptable step adjacent the end portions is obtained, the tapering means including the upper surface of the base adjacent the particular end portion being devoid of projecting means, the suction means provided beneath the particular end portion having sizes which decrease incremantally from a maximum to a minimum height adjacent to the end edge of the base, so that when the tread device is laid flat on the road surface and aligned with the tire and the suction means face upwards, with the side edges of the tread device straddling the tires symmetrically, the tread device can be secured to the tire by rolling the tire over the tread device so that the suction cups of decreased size engage the tire initially, so that the end portion of the tapering means lies substantially flush with the tire so as to produce a smooth transition from the tread face to the upper surface of the tread device, the remaining portion of the device subsequently being brought into engagement and secured to the tread face the opposite end portion overlapping the tapering means so as to produce a relatively smooth outer periphery.