GB691587A - Pneumatic tyre - Google Patents

Abstract

691,587. Pneumatic tyres. SEIBERLING RUBBER CO. Dec. 31, 1951, No. 30436/51. Class 144 (ii). In a tyre having a tread 11 formed by heavyduty circumferentially-spaced traction lugs 13 extending laterally from each side of a central circumferential rib 14 to opposite side edges of the tread, one or more circumferential slits 20, 21 extend radially inwardly from the surface of each lug 13 to a substantial depth without reducing the forward traction qualities of the lugs, the slits 20, 21 forming blocks which are laterally flexible to minimize lateral skidding. As shown, the lugs 13 are parallel on both sides of the rib 14 and their outer surfaces are laterally arcuate with the axially outer edges rounded, to merge with the tyre side walls 15, at a radius at least equal to the depth of the grooves 12 between the lugs 13. Two parallel slits 20, 21 are cut in each lug 13, the outermost slit 21 being adjacent the junction of the rounded lug corner with the crown surface of the lug. The slits are cut normal to the curvature of the tread and extend to a depth of one-third to two-thirds of the depth of the grooves 12. A plurality of spaced circumferential slits may extend over the length of each lug 13.