Tire Traction Device

1. Field of the Invention

This invention relates to removable tire traction devices, and more particularly, to a lightweight, easily installed traction device which creates a vacuum to cause the traction device to grip the abutting surface of the tire and the road surface.

2. Description of the Prior Art

Conventional tire chains have long been used to increase traction between tires and road surfaces which have become slippery because of ice and snow. Although these devices are effective in increasing traction, they suffer from a number of disadvantages. The principal disadvantage is the difficulty of installing and removing conventional tire chains due to their heavy weight and construction. Another disadvantage of tire chains is the roughness of the ride when tire chains are installed on the vehicle tires.

In order to eliminate or at least reduce the aforementioned disadvantages inherent in conventional tire chains, a number of lightweight substitutes have been developed. One such device is disclosed in U.S. No. De. 247,291. The traction device of the patent utilizes a plurality of elongated traction members, each having fastening strips secured to their ends. The traction members are secured about the periphery of a tire by passing a pair of flexible belts through the fastening member at opposite sides of the tire. The outer surface of the traction members includes a plurality of pointed projections which are integrally formed with the traction element. However, as the traction device is used, the projections wear rapidly due to road abrasion. The outer surface of the traction members eventually becomes planar and the traction members lose a substantial portion of their effectiveness.

The principal object of the present invention is to provide a device for increasing the traction between a tire and the surface of a road. The device can be installed and removed with relative ease and yet is substantially as effective as conventional tire chains.

Another object of the invention is to provide a lightweight tire chain substitute which will incur substantially less wear and loss of effectiveness after prolonged use.

These and other objects of the invention are accomplished by utilizing a plurality of traction members which are mounted on a tire in substantially the same manner as are the traction devices illustrated in the aforementioned patent and are thus relatively easy to install and remove. However, the inventive traction members herein disclosed and described have a generally planar outer surface and a plurality of suction cavities are formed inwardly from the rear surface with a plurality of apertures extending between the suction cavity and recesses formed in the outer surface. As the tire rolls along a road surface, the traction members sequentially contact the road surface so that the suction cavities are sealed by the tire while the apertures are sealed by the road surface. Consequently, a suction is created in the suction cavity which draws the traction member toward both the tire and the road surface, thereby creating a traction which approaches the traction provided by conventional tire chains.

FIG. 1 is an isometric view of the traction device installed on a conventional tire;

FIG. 2 is a top plan view of one member of the traction device;

FIG. 3 is a bottom plan view of one member of the traction device;

FIG. 4 is a cross-sectional view taken along the line 4--4 of FIG. 2;

FIG. 5 is a cross-sectional view taken along the line 5--5 of FIG. 2; and

FIG. 6 is an enlarged side view illustrating the overlapping relationship of the fastening strips.

The inventive traction device as shown in FIG. 1 is installed on a conventional tire 10. The device includes a plurality of traction members 12 molded in a single piece. Each traction member includes a central traction section 14 and fastening strips 16, 18. Fastening strips 16, 18 are formed at opposite ends of the traction sections. The fastening strips 16, 18 are formed to receive flexible belts or straps 20, 22, respectively, having their ends joined by conventional buckles, not shown.

The structural details of the traction sections 14 are illustrated in greater detail iln FIGS. 2-5. The traction section 14 includes a central gripping area having scalloped edges or sidewalls 26 as illustrated in FIG. 2. The outer surface of the traction section is generally planar, as best illustrated in FIG. 4. The inner face 25 of the traction section 14 as illustrated in FIG. 3 has formed therein a plurality of suction cavities 28 formed by the scalloped sidewalls 26, a central longitudinal wall 30, end walls 32 and transverse intermediate walls 33. A plurality of spaced-apart apertures 34 are formed in the plastic material and extend from the suction cavities 28 toward the planar outer surface of the traction section 14. Recesses 35 are formed on the outer surface of the traction sections 14 in alignment with the apertures 34. The recesses have a substantial diameter and extend to a depth of approximately one-half the thickness of the material between the outer surface and the cavities 28. Continuing from the base of each of the recesses 35 to the suction cavities are apertures 34 of relatively small diameter. Thus is provided a continuing air passage between the outer face 24 and suction cavities 28. As the tire 10 rolls along a road surface, the traction sections 14 contact the road surface, producing a vacuum and maintaining a suction within the suction cavities 28 which, through the recesses 35 and apertures 34, provide a relatively high degree of traction between the traction member, the tire and the road surface.

As best illustrated in FIGS. 2, 4 and 5, the fastening strips 16, 18 are generally T-shaped and include an arcuate portions 36-36 containing a plurality of slots 38 for receiving conventional flexible belts 20, 22, preferably of woven nylon. As best illustrated in FIG. 5, the belts are recessed within cavities 42 formed in the inner and outer faces of the arcuate portions 36.

When the traction device is applied for use, it is installed in much the same manner as conventional tire chains. However, since the traction members 12 are relatively light in weight and are flexible, it is a relatively easy task to install the traction device. As the tire 10 rolls along a road surface, the traction sections 14 sequentially contact the road surface or a layer of ice or snow covering the road surface. As the wheels rotate, the weight of the vehicle applied to the traction section exhausts the air from the suction cavities. The contact between the tire 10 and the inner face of the traction section 14 seals the suction cavities 28, since the walls 26, 30, 32 completely contact the tire surface. Similarly, the recesses 35 and apertures 34 are sealed when the outer surface of the traction section 14 contacts the road surface. Under these circumstances, the air in the cavities is expelled, thereby creating a vacuum and a resulting suction and maintained within the suction cavities 28 which causes the traction section 14 to grip both the tire 10 and the road surface, thereby providing a relatively high degree of traction between the tire and the road surface. As the tire continues to roll along the road surface, the suction between either the suction cavities 28 and tire 10 and road surface is broken, thereby destroying the vacuum in the suction cavities 28.

The reason for providing the relatively larger diameter recesses 35 and the smaller aperture passages 34 is to create a greater pressure from the suction cavities to clear the recesses and apertures when the vacuum is broken incident to rotation of the tire. The velocity of air through the apertures will be of higher velocity and clear the apertures and recesses of dirt or passage plugging substances.

As is best illustrated in FIG. 6, the fastening strips 16, 18 are formed at their opposite ends 17, 19 with portions of reduced thickness so that the adjacent traction members may be caused to overlap. The belts 20 may then be laced through adjacent overlapping portions to hold the traction members in the overlapping relationship.

It can therefore be seen that the inventive traction device is relatively easy to install and remove and it is relatively more efficient in its traction creating capabilities.