Fuer alle Gelaende verwendbare Luftreifen

1,057,192. Pneumatic tyre treads. COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN, RAISON SOCIALE MICHELIN & CIE. April 23, 1964 [April 26, 1963], No. 16907/64. Heading B7C. A pneumatic. " on-and-off-the-road " tyre tread for a tractor comprises a single central circumferential upstanding ring, to provide a road running surface, and bars 2 for improved traction in soft ground extending at an angle alternately from each side thereof, the ring having grooves 4 of a depth less than the height of the ring to divide it into blocks 1, and the bars being similarly separated from the ring by grooves 3 so that each ring block and bar is able to flex independently of the neighbouring blocks or bars. The depth of the grooves 3, 4 is preferably between 20 and 90% of the height of the bars and blocks respectively, arid the width A of the ring is at least 40% greater than the maximum width L of any block. The bars may be alternately long and short on each side of the ring, or may comprise blocks similar to blocks 1. The maximum width L of a block is greater than the maximum width n or s of a bar measured respectively perpendicularly and parallel to the midplane XY. The front end in the rolling direction of each block has faces ae, ec each making an angle of between 40 and 80 degrees with the midplane, and its side faces ba, dc make an angle of not more than 15 degrees with the midplane.