Raisable and lowerable support

摘要

The manoeuvring control (20) comprises two cogged bars (31,30) movable in their longitudinal direction. Two wire coils (50) are connected to the cogged bars, and partly run inside each inner tube (4) with which they are connected so that the tube follows the coil movement. A rotary driven gearwheel (25) produces the movement of the cogged bars, and the wire ciols run over guide rollers (41-45).