Abstract: A traction system for a vehicle has a support frame that defines a circular track belt support that is revolvable about an axis at its center, a flexible track belt; and a track belt stretching assembly comprising one or more track belt stretching rollers. The system has one traction configuration in which the flexible traction belt is held on said support track forming a substantially circular, wheel-like traction surface, and can change to a stretching state in which said rollers engage said belt and stretch it from its state in said one traction configuration to a stretched state to define one or more other traction configurations of the system.

Abstract: A transport mechanism (104) for transporting a load-assembly (102), the transport mechanism comprising a closed flexible track (106) supported at an internal side thereof by at least two support rollers (108, 110), which at a first position one of the support rollers (108) exerts a force having a downward component onto the flexible track (106) at a point of contact thereof with a ground surface and biasing arrangement for biasing said flexible track (106) so as to assume a substantially circular shape. A displacing mechanism (112) is coupled to at least one of the support rollers for mutually displacing the support rollers into a second position, against the biasing arrangement in which the support rollers force the track to assume a state in which an extended portion (122) thereof is in contact with the ground surface and at least two of the support rollers are positioned at two ends of the portion.