The frame structure has two adjacent bent pipes (1, 2) which extend in the longitudinal direction of the vehicle and are inclined towards each other. In the illustrated side view, only the bent pipe (1) on the left side of the vehicle can be seen. This bent pipe (1) has a shape similar to that of a bowsaw. The idea underlying the invention is that the weight of the vehicle occupants acts on the bent pipe structure and is deflected into forces which push the two ends (4; 6) of the pipe away from each other. These deflected forces are in turn absorbed by pipes (10, 11) arranged in the longitudinal direction of the vehicle and which indirectly interconnect the ends of the bent pipes (1, 2) absorbing the traction forces therebetween. The two bent pipes (1, 2) are inclined towards each other and thus form a gable, seen in the longitudinal direction. The forces exercised downwards by the weight of the drivers upon this structure are thus deflected not only into traction forces acting between the front and rear ends (4, 5; 6, 7) of the bent pipes, but also into traction forces acting between the two front ends (4, 5) and the two rear ends (6, 7) of each bent pipe.
