Abstract: A known shock absorber including a throttle cross section of a throttle passage which is electrically variable via a magnet, to adjust damping of fluid between separate work chambers. If the magnet has no current in the event of an electrical defect, then the throttle cross section of the throttle passage attains its minimum opening, and maximum damping is attained the shock absorber includes a different further throttle passage which is uncovered in the event of an electrical defect. As a result, in the event of an electrical defect an arbitrarily preselectable, preferably approximately average damping is brought about by the further throttle passage.

Abstract: In previously known shock absorbers, a throttle cross section can be controlled with the aid of a control slide. Because flow forces can never be avoided entirely, the magnetic force must be controlled as a function of the flowing pressure fluid flow. In the cylinder proposed here, having a control slide, an additional force acting upon the control slide results, which is directed counter to these flow forces and can at least partially compensate for them. The proposed cylinder is intended in particular for use as a shock absorber for vehicles.

Abstract: A pressure-actuated valve which includes an effective pressure face by which the valve is opened, the face on which the pressure difference that opens the valve acts is completely independent of an openable flow opening. The effective pressure face and the openable flow opening can be selected arbitrarily within wide limits, independently of one another. The pressure-actuated valve according to the invention is preferably suitable for shock absorbers.