Antiskid device for motor vehicles

An antiskid device for driving motor vehicles on snowy or icy roads, which comprises

• a hub portion securable to the outside of a motor vehicle wheel and formed with an axial recess and a plurality of radial bores angularly spaced apart from one another,
• a peripheral crown including a plurality of curved sectors sequentially articulated to one another and each having roadbed gripping means, thereby forming an uninterrupted deformable rim,
• a plurality of fluid-operated telescopic spoke elements each having one end thereof received in a respective radial bore in the said hub portion and in fluid communication with said axial recess and its other end pivoted to a respective cured sector of the crown, a fluid distributor assembly idly mounted in the said axial recess and arranged to sequentially supply compressed fluid to each radial bore,
• a compressed-fluid source operatively connected to said distributor assembly and arranged to feed compressed fluid to the said fluid-operated telescopic spoke elements to cause the said peripheral crown to expand from a contracted position, in which the said deformable rim is smaller in diameter than the motor vehicle wheel, to an extended working position in which it is larger in diameter,
• return means arranged to urge the said telescopic spoke elements, and thus the peripheral crown to contract from an extended to a contracted position, and
• retention means designed to withstand centrifugal forces, thereby holding the said telescopic spoke elements and thus the said deformable crown in their contracted position while driving on non-snowy or non-icy roads.