Abstract: The invention relates to a filter device for filtering a hydraulic fluid comprising a housing having fluid through-openings for hydraulic fluid to be filtered to flow into the housing and for filtered hydraulic fluid to flow out of the housing, and having an assembly opening for inserting a filter element into the housing, the assembly opening being closable by a cover. In order to further develop the filter device such that it can be selectively configured in a cost-effective manner as a suction filter, return filter or return-suction filter, it is proposed in accordance with the invention that different filter elements be insertable into the housing, and that different functional modules be insertable into the housing or connectable to the housing.

Abstract: A control arrangement for a hydropneumatic suspension system and a hydropneumatic suspension system are provided. The control arrangement has a pressure supply connection, a return connection, a piston chamber connection adapted to be connected to the piston chamber of a suspension cylinder of the hydropneumatic suspension system, an annular chamber connection adapted to be connected to the annular chamber of the suspension cylinder, and at least one controllable valve arrangement comprising a plurality of switch positions via which the pressure supply connection and the return connection are connectable to the piston chamber connection and the annular chamber connection. The annular chamber connection is in flow connection with the return connection via a pressure-limiting line having a hydraulically controllable pressure-limiting element. The pressure-limiting element has a control input adapted to be acted upon via a control line by a control pressure which is limitable to a predefinable pressure limit.

Abstract: The invention relates to a proportional directional control valve for controlling a hydraulic consumer, having a housing with a pressure port, a tank port, and first and second working ports. A control element is movably mounted in the housing. A single actuator is provided for moving the control element, which, in dependence on its position relative to the housing, enables different flow paths between the ports. The control element, starting from a first switching position in which both working ports are connected to the tank port, is movable by the actuator via a second switching position that follows the first switching position, to a third switching position that follows the second switching position. It is possible, by moving the control element from the first switching position into the third switching position, to successively disconnect the two working ports from the tank port and connect them to the pressure port.

Abstract: A control arrangement for a hydropneumatic suspension system and a hydropneumatic suspension system are provided. The control arrangement has a pressure supply connection, a return connection, a piston chamber connection adapted to be connected to the piston chamber of a suspension cylinder of the hydropneumatic suspension system, an annular chamber connection adapted to be connected to the annular chamber of the suspension cylinder, and at least one controllable valve arrangement comprising a plurality of switch positions via which the pressure supply connection and the return connection are connectable to the piston chamber connection and the annular chamber connection. The annular chamber connection is in flow connection with the return connection via a pressure-limiting line having a hydraulically controllable pressure-limiting element. The pressure-limiting element has a control input adapted to be acted upon via a control line by a control pressure which is limitable to a predefinable pressure limit.

Abstract: The invention relates to a corrugated or pleated flat material with a plurality of pleats or corrugations that run parallel to one another and successively define a pleat or corrugation peak and a pleat or corrugation valley, the peak and valley being connected to one another by way of a pleat or corrugation flank, wherein a fluid can flow through the flat material and the flat material has at least one deformable functional layer which rests on a supporting layer in the direction of throughflow of the fluid, said supporting layer comprising a supporting fabric, the functional layer allowing foreign substances to be removed from or delivered to the fluid. In order to develop the flat material in such a way that it has greater mechanical load-bearing capacity and lower resistance to throughflow, it is proposed according to the invention that the supporting fabric is deformable and comprises a twill weave.

Abstract: The invention relates to a process for releasing at least one spring accumulator brake (10), which is operated by a pressure medium and which is connected to a brake-release-pressure-supply-circuit (63) in normal operation for impact with a brake release pressure and which, in service operation, is detached from the circuit (63) in case of failure of the brake release pressure and is released through a pressure medium source (37) against the spring force of the spring accumulator. To develop the process in such a way that the risk of an accident taking place reduces after the brake release pressure has failed, it has been proposed in the invention that at least one brake (10) gets re-connected automatically with the circuit (63) when the brake release pressure is provided again. Further, an apparatus and a hydraulic circuit for carrying out the process are proposed.

Abstract: The invention relates to a corrugated or pleated flat material with a plurality of pleats or corrugations that run parallel to one another and successively define a pleat or corrugation peak and a pleat or corrugation valley, the peak and valley being connected to one another by way of a pleat or corrugation flank, wherein a fluid can flow through the flat material and the flat material has at least one deformable functional layer which rests on a supporting layer in the direction of throughflow of the fluid, said supporting layer comprising a supporting fabric, the functional layer allowing foreign substances to be removed from or delivered to the fluid. In order to develop the flat material in such a way that it has greater mechanical load-bearing capacity and lower resistance to throughflow, it is proposed according to the invention that the supporting fabric is deformable and comprises a twill weave.

Abstract: The invention relates to a process for releasing at least one spring accumulator brake (10), which is operated by a pressure medium and which is connected to a brake-release-pressure-supply-circuit (63) in normal operation for impact with a brake release pressure and which, in service operation, is detached from the circuit (63) in case of failure of the brake release pressure and is released through a pressure medium source (37) against the spring force of the spring accumulator. To develop the process in such a way that the risk of an accident taking place reduces after the brake release pressure has failed, it has been proposed in the invention that at least one brake (10) gets re-connected automatically with the circuit (63) when the brake release pressure is provided again. Further, an apparatus and a hydraulic circuit for carrying out the process are proposed.