Adaptable traction system of a vehicle

1. A traction system for a vehicle, comprising:

a support frame defining a substantially circular track belt support that is revolvable about an axis at the center of the support frame, said axis being in a fixed position with respect to a chassis of the vehicle;

a flexible track belt; and

a track belt stretching assembly comprising one or more track belt stretching rollers;

said system having one traction configuration in which the flexible traction belt is held on said support track forming a substantially circular, wheel-like traction surface, said belt stretching assembly can change to a belt stretching state in which said rollers engage said belt and stretch said belt out from said belt's relatively relaxed state in said one traction configuration, to a stretched state to define one or more other traction configurations of the system.

2. A traction system according to claim 1 , wherein said rollers are held on distal ends of belt extension arms attached at the proximal end of said belt extension arms to the vehicle's chassis.

3. A traction system according to claim 2 , wherein said revolvable support frame comprises two coaxial circular cooperating support members with a gap between said coaxial circular cooperating support members defining together said circular track belt support, a void space extending radially from the axis to the lateral part of said gap defining a track belt stretching assembly-holding space, said belt-stretching assembly being housed within said space in said one traction configuration.

4. A vehicle comprising one or more traction systems according to claim 1 .