Tyre fitted with withdrawable spikes in tread - has internal diaphragm which is cured circumferentially inside shoulder and can be pressurised to force spikes out through holes in tread

摘要

A tyre has tread features from which spikes can be moved out or withdrawn again by means of a cover operated with compressed air. The cover is applied to the interior of the tread; it forms an inner chamber which can be filled with compressed air or vented again; the spikes are on the chamber side of the cover and they can move through holes in the tread. Pref. the tread (3) with the internal chamber (13) which is held at the same pressure as the tyre interior (21) or higher, and the spikes (7) are withdrawn i.e. in their normal position. Inside the main interior (21) is the pressure cover (5); this is cured in position on to the inside wall of the tyre by circumferential wedge-shaped pieces (9). This structure prevents excessive thickening at the critical shoulder area (4). Both the cover (5) and wedges (9) are cold cured i.e. contain suitable curing catalysts etc. A valve arrangement either admits the main tyre pressure or simply atmospheric pressure to the chamber (13). The tyre can be initially supplied with the holes (8) plugged so that it is then modified if required. ADVANTAGE - The design of the tyre is simple. It meets the latest technical specifications (unlike earlier types).