GB956011A - Improvements in or relating to pneumatic vehicle wheel tyres - Google Patents

Abstract

956,011. Replaceable tread tyres. PIRELLI S.p.A. Feb. 9, 1961 [Feb. 10, 1960], No. 4850/61. Heading B7C. A replaceable tread tyre comprises a casing formed with a substantially cylindrical seat 2 on its outer periphery bounded by circumferential ribs 3, and a plurality of separate tread rings 4, 5, each interiorly reinforced as at 6 by one or more layers of circumferentially or helically extending parallel inextensible cords or convolutions of cord, maintained in axially spaced relationship in the seat by spacing elements 8 which are separate from the tyre. The spacing elements 8 may be of trapezoidal, square or rectangular cross-section with or without interior reinforcement, and may be separate from or integral with the tread rings. Fig. 2 shows a central tread ring 4 spaced by elements 8 from lateral tread rings which are each in two parts 5<SP>1</SP>, 511 separated by a spacing element 10. The outermost ring parts 511 have reinforcements 7<SP>11</SP> of smaller diameter than that 7<SP>1</SP> of the ring parts 5<SP>1</SP>, and the reinforcements 7<SP>1</SP> may have the same, or a smaller, diameter than the reinforcement 6 of ring 4. The lateral portions 2<SP>1</SP> of the casing seat 2 may be conically flared axially outwardly at an angle of 2 degrees to 10 degrees to the tyre axis. In a further embodiment the tread rings may have axial projections on their adjacent sides to abut each other in overlying relationship to the separate spacing elements 8. Fig. 4 shows a further arrangement wherein the laterally outermost tread rings 5 have a conical layer of reinforcements 7, and wherein intermediate tread rings 13 have an inner peripheral axial extension 14 on each side thereof to space the rings 13 from the central ring 4 and lateral rings 5. In this case, the reinforcement of the rings 13 is extended into the extensions 14. In an alternative arrangement, extensions 14 may be incorporated on all adjacent faces of the rings 4, 5 and 13. Specifications 755,990, 787,705, 864,909, 874,292, 879,926 and 910,539 are referred to.