Abstract: A model of a telescopic boom including at least three tubular sections arranged in a row one after another and an outer cross-section of which becomes smaller from a tubular section to a tubular section in a direction toward a free end of the telescopic boom, with each of the tubular sections forming, at its front end, a cut-out into which a bar provided at a rear end of a preceding, in the direction toward the free end of the telescopic boom, tubular section, projects in a pull-out condition of the telescopic boom, with the front bar surface of a bar projecting, in the pull-out condition of the boom, beyond the cut-out, and with the rear abutment edge of the cut-out facing the rear surface of the bar.

Abstract: A prototype undercarriage, wherein an undercarriage unit is mounted on a truck base unit 2 provided for carrying a body structure 1, in that a transverse member 5 of the undercarriage unit is fastened to a counter-member of the base unit, and the transverse member 5 carries a mounting bracket 7 cast in one piece at each end, from each of which a rocker means 13 extends and in which the two rocker means 13 are cast in one piece with a rigid axle and each carry a spring means 9, 14 that is cast in one piece and situated on the side of the rigid axle opposite to the associated mounting bracket 7. In this case it is desirable, if the rocker means is a swivel mounted, separate pivot member.