CONTROL- AND OPERATING SYSTEM, IN PARTICULAR FOR A HYDRAULIC ACTUATOR OF A FOLDING ROOF OF A VEHICLE

摘要

Control and operating system comprising a hydraulic cylinder (1) for moving a load (2). The piston (3) bounds a working chamber (4) which, if fed with oil, moves the load connected to the piston against the force of gravity. The working chamber (4) is connected to a pump (7) through a line (6) in which a non-return valve (10) and an electromagnetic control valve (12) are accommodated. When not energized, the working chamber (4) is connected to a reservoir (9), and when energized to the pump (7). The control unit is designed in such a way that in the "holding" position of the control button - the control valve (12) is energized continuously for a first period, and in a subsequent, second period is energized and not energized intermittently. As a result of this, the load is lowered stepwise during the second period.