Abstract:
A spike tire for a vehicle and which includes a pin receptacle hole formed on the tread surface of the tire; a spike pin retractably protrudable from the pin receptacle hole; a biasing mechanism for continuously urging the spike pin to protrude from the pin receptacle hole; and an actuating member of a shape memory alloy capable of restoring a memorized shape when warmed to a predetermined temperature by the heat generated in the tire as a result of operation of the vehicle on a non-frozen or snow-free road surface, to thereby retract the spike pin into said tire against the action of the biasing mechanism. The spike pin is automatically protruded and retracted depending upon road conditions based on a temperature difference between a frozen or snowed road surface and a non-frozen snow-free road surface. On a non-frozen bare road, the spike pin is automatically retracted into the pin receptacle hole by restoration of a memorized shape of the shape memory alloy thereby preventing damage and abrasive wear of road surfaces and the resulting generation of pollutional dust.
Abstract:
A stud unit (3) and a device (1) for a studded tyre. The stud unit comprises a housing (5) with a chamber (7) enclosing a medium, a stud (20) arranged at least partly inserted into the chamber so that it is affected by the medium. The stud is adapted to be moved depending on a change of the pressure of the medium in the chamber between a first position for a first pressure and a second position, where the second pressure is higher than the first pressure. In the second position a part of the stud protrudes further from the chamber than in the first position, The stud unit also contains a heating element (22) adapted to heat the medium so that the pressure in the chamber is adjusted between the first pressure and the second pressure.
Abstract:
An antiskid device (A) mounted to a tread (20) of a tire (2) has a pin (10) and a heat insulating member (11) attached to an end of the pin (10). The pin (10) is made of a material having a higher hardness in a first temperature range not higher than a predetermined temperature and a lower hardness in a second temperature range above the predetermined temperature. The insulating member (11) prohibits heat transfer from the tire (2) to the pin (10).