Abstract: A pneumatic or hydropneumatic spring system, especially for motor vehicles, has a plurality of separate spring units among which a valve-controlled pneumatic or hydraulic pipeline system is disposed. Thereby, the spring units can be connected to or disconnected from one another or connected to a pneumatic or hydraulic pressure source or to an outlet. The pipeline system also has a central in-and-out pipeline with a pressure sensor. The valves are so disposed that given or giveable system parts or system areas can be connected separately to the in-and-out line. A central in-and-out line is provided with a pressure sensor, and the valves are so arranged that given or giveable system parts can be connected separately to the in-and-out line and thus to the pressure sensor to determine pressure.

Abstract: The invention relates to a valve-controlled positive displacement pump having valve triggering, which permits the forced opening or keeping open of an inlet valve, operating in the manner of a non-return valve, of a displacer working space, so that the displacer working space remains connected to the inlet side of the unit even during the working stroke of the displacer, and the assigned displacer is not able to work efficiently. The design according to the invention is particularly suitable for radial piston pumps.