as a linear damper is arranged between the pressure component 12 or the slider 15 which is capable of linear movement and a stationary stop 17 formed on the housing 10 see fig4 furthermore the support arm 2 has a stop 19 for the damper 18 see fig3 if the lid 4 is raised and the support arm 2 approaches the uppermost stop position the slider 15 which is capable of linear movement presses on the damper 18 which is supported on the other hand by the stop 17 therefore the damper 18 cushions the pivotal movement of the support arm 2 within this range if the lid 4 is lowered and the support arm 2 approaches its lowest stop position the stop 19 of the support arm 2 presses on the damper 18 of which the end disposed opposite to the stop 19 is supported by the slider 15 and which is capable of linear movement in this manner the support arm 2 is cushioned before reaching the lower stop position that is to say before reaching the closed position of the lid 4 accordingly one damper 18 is sufficient to cushion the movement of the support arm 2 for the opening and also for the closing of the lid 4 in the illustrated embodiment the support arm drive 1 is fitted with a single damper 18 which brakes the support arm 2 just before it reaches the.