Abstract: A device to increase the grip of the tread of the wheel of a vehicle is disclosed. A base is secured to the outside of the face of the rim of a wheel, and a plurality of moving spokes whose ends are connected to claws are elastically connected to each other to form a belt whose diameter progressively increases during its positioning. The moving spokes cause the belt to switch from a retracted rest configuration having the shape of an annulus, in which the claws are arranged inside the perimeter of the base (2), to a configuration that make its extension progressively increase around the tread, wherein the claws contact a roadbed.

Abstract: A device to increase the grip of the tread (11) of the wheel (10) of a vehicle comprising a base (2) provided with appropriate means for securing it to the rim of said wheel (10), in correspondence with the face thereof destined to be arranged outside, and a plurality of moving spokes (4) whose ends are connected to claws (55), the latter being elastically connected to each other to form a belt (5) whose diameter progressively increases during its positioning; said moving spokes (4) being suitable for making, upon command, said belt (5) switch from a retracted rest configuration having the shape of an annulus, in which said claws (55) are substantially arranged inside the perimeter represented by said base (2), to an extracted work configuration, so as to make its extension progressively increase up to allowing its arrangement around said tread (11), said claws (55) getting in contact with the roadbed; characterized in that the means for positioning said moving spokes (4) comprise a plate grooved according to