Patent ID: 7624778

Claim:
A traction device for a vehicle comprising: a plurality of spikes, each of which is formed with a supporting device having a triangular shaped contacting portion including an inside surface facing toward an outer peripheral edge of dual wheels and both a right and a left leg of the triangular shaped contact portion contacting between the dual wheels so that the spike can be supported between tires of the dual wheels, a friction plate engaged with the supporting device at the outer peripheral edge of the dual wheels to produce the friction by contacting with the dual wheels, and an engaging portion formed at a radially inward apex of the triangular shaped contacting portion between the tires of the dual wheels; an interval maintaining device adapted to engage with the engaging portion of the spike by insertion of a wire and maintain the intervals between the plurality of spikes; and a locking portion including a ring shaped locking hook formed at one end of the wire of the interval maintaining device, an engaging lever having a length adjusting device and an elastic body formed at the other end of the wire, and a retention device projecting from the wire to engage one of the spikes, wherein the locking hook is adjusted in length by the length adjusting device and the elastic body to engage the engaging lever and movement of the spike engaged by the retention device is prevented by the retention device during installation of the plurality of spikes on the dual wheels after the spikes have been engaged with each other by the interval maintaining device.