Patent ID: 7546890

Claim:
A motor vehicle comprising: a chassis with at least two axles having wheels; an additional crawler undercarriage being arranged between the at least two axles, said additional crawler undercarriage having carrying wheels and revolving crawlers comprising traction belts made of a textile-rubber belt having transverse webs; a mounting assembly with an electro-hydraulic system for extendible and retractable connection between the additional crawler undercarriage and the chassis; a drive unit, which includes a connectable drive system with an output from a driven wheel for selectively transferring power from the motor vehicle to the additional crawler undercarriage, said additional crawler undercarriage having a traction-effective running surface with an adjustable ground-contact length, a second drive means capable of changing a position and a vertical spacing of the additional crawler undercarriage relative to the chassis; and a control unit for controlling the additional crawler undercarriage, said control unit being integrated in the connectable drive system and capable of controlling the ground-contact length of the traction-effective running surface; wherein the ground-contact length of the running surface is shorter than a distance between the at least two axles, and wherein the carrying wheels roll on the traction belts and the transverse webs; wherein the connectable drive system comprises a friction roller drive.