This invention relates generally to tools for use by car and truck drivers in the mounting of tire chains and, more particularly, to such devices also useful for other purposes for supporting vehicle wheels to facilitate positioning of the chains.
Tire chains have commonly been mounted on tires by spreading the chain along the ground, driving the tire to be chained over the chain, and subsequently wrapping the chain around the tire and hooking the two end chain links to two fasteners. Getting a tight, square fitting of the chains and uniform spacing of the cross-links using a method is difficult, particularly for the inexperienced individual. The difficulty is primarily caused by the tire resting on at least one, and usually two, of the cross-links. Further, as the tire is initially moved over the chain, the cross-links generally move forward or become applied slightly, thus making it difficult to achieve a uniform spacing of the cross-links and a snug fit of the chain around the tire.
One well-known way to avoid this problem is elevating the tire. Since drivers often do not have access to a vehicle hoist, they can elevate the vehicle only by manually jacking up a corner or axle of the vehicle. Doing so is inconvenient as at least two corners or wheels of the vehicles must be jacked up one at a time. Frequently, a driver does not learn of the need to mount the chains until confronting an icy or muddy road. Such a surfce does not securely support a jack. Often it is necessry to chock the other wheels so that the vehicle does not roll while jacked up. This procedure is time-consuming, dirty, and dangerous to the installer.
Besides jacking the car up, attempts have been made to elevate a tire and thereby permit limited movement of the chain therebeneath. For example, one manufacturer provides an elongated plastic chain-carrying box having its two ends upwardly sloped to provide ramps so that a vehicle tire can be driven up onto a flat top of the box. The ramps are formed with horizontal cross ribs in an effort to provide traction to the tire and prevent the box from being pushed forward. A rectangular recess is provided across the top of the container to receive a cross-link of a tire chain. In operation, an operator inserts a cross-link in the rectangular recess and spreads the chain along the ground. The tire to be chained is driven up the ramp onto the box. The cross-link, which is now directly beneath the tire, is movable in the rectangular recess, thus permitting a tight, uniform fit of the chain around the tire. Such a device is limited in its use, however, as the combination chain container and vehicle support commonly has a two thousand pound weight limit, thus preventing its use by large vehicles such as trucks. Also, the plastic traction ribs are only marginally effective due to the height and steepness of the ramp and rounded shape of the ribs. Furthermore, the plastic material wears out and eventually cracks and breaks, making the device useless or at best hazardous.
Another device includes two short lengths of lumber, such as two two-by-fours, position parallel and nailed onto a plywood base at a spacing sufficient for positioning a cross-link of a tire chain therebetween. The operator spreads the chain out, placing a cross-link between the two lengths of lumber, and thereafter drives the tire to be chained onto the lengths of lumber. The cross-link is movable beneath the tire, and thus facilitates achieving a tight, uniform fit of the chain around the tire. This device almost invariably slides forward as the tire approaches, unless cleats or other traction means are provided on a lengthwise extension of the base for engaging the tire to prevent slippage. The two-by-four boards provide little traction, especially for wet tires.
Accordingly, there remains a need for a device that facilitates the mounting of tire chains which is safe, can withstand the weight of a heavy vehicle, and will not slide forward when contacted by an approaching tire.