A fail-safe drive (1) for an actuating drive is provided, which has a cam disc (8), at least one restoring element, a counter-element (5) and an output shaft (3), with the cam disc (8) and the counter-element (5) being configured for joint conversion of an axial movement of the restoring element along the output shaft (3) into a rotational movement of the output shaft (3). The cam disc (8) has a control cam (10), the profile of which is adapted to a spring characteristic curve of the restoring element such that, in the case of activation of the failsafe drive (1), a constant output movement and/or a constant output torque can be generated.

A sealing ring includes a first sealing element having a first mating surface and a second sealing element having a second mating surface. A high-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element, and a low-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element. The first mating surface, the second mating surface, or both, includes a recess open to the low-pressure boundary and not open to the high-pressure boundary. The recess may include a groove, for example. The first mating surface is sealed against the second mating surface by a first force acting on the first sealing element and a second force acting on the second sealing element. These forces act to pressure-lock the assembly.

A sealing ring includes a first sealing element having a first mating surface and a second sealing element having a second mating surface. A high-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element, and a low-pressure boundary extends across at least a portion of the first sealing element and across at least a portion of the second sealing element. The first mating surface, the second mating surface, or both, includes a recess open to the low-pressure boundary and not open to the high-pressure boundary. The recess may include a groove, for example. The first mating surface is sealed against the second mating surface by a first force acting on the first sealing element and a second force acting on the second sealing element. These forces act to pressure-lock the assembly.

A fluid pressure cylinder includes first through fourth stepped portions provided in a multi-stepped manner on a first spigot joint of a head cover, and first through fourth stepped portions provided similarly in a multi-stepped manner on a second spigot joint of a rod cover. A cylinder tube is installed selectively on any one pair of the first through fourth stepped portions. Consequently, by preparing a new cylinder tube that differs in diameter, along with a new piston, and then installing the cylinder tube selectively on any one pair of the first through fourth stepped portions, a fluid pressure cylinder having a different bore diameter is constructed.

A fluid flow control device includes a body having an inlet connection, an outlet connection, and a discharge port. A supply path extends between the inlet connection and the outlet connection and a booster module is disposed within the body. The booster module includes a control element and an actuator element and defines an exhaust path extending between the outlet connection and the discharge port. A supply port is disposed within the booster module along the supply path between the inlet connection and the outlet connection.

A fluid flow control device includes a body having an inlet connection, an outlet connection, and a discharge port. A supply path extends between the inlet connection and the outlet connection and a booster module is disposed within the body. The booster module includes a control element and an actuator element and defines an exhaust path extending between the outlet connection and the discharge port. A supply port is disposed within the booster module along the supply path between the inlet connection and the outlet connection.

A master cylinder for a regulated braking system having at least one piston, which is movable in a housing and which is sealed from a pressure chamber by a sealing element arranged in a ring groove of the housing, which can be connected to an unpressurized supply chamber by control passages designed in the pistons. In order to reduce the flow resistance of the control passages at the same dead stroke, the control passages have a control edge designed parallel to a piston end face of at least one of the pistons.

A master cylinder for a regulated braking system having at least one piston, which is movable in a housing and which is sealed from a pressure chamber by a sealing element arranged in a ring groove of the housing, which can be connected to an unpressurized supply chamber by control passages designed in the pistons. In order to reduce the flow resistance of the control passages at the same dead stroke, the control passages have a control edge designed parallel to a piston end face of at least one of the pistons.

A method of controlling a hydraulic system, the hydraulic system including a ram cylinder unit having a cylinder and a ram, and a hydraulic pump and a reservoir used to supply hydraulic fluid to the cylinder, and hydraulically driving the ram using the hydraulic fluid so as to move against a specific load, the method includes determining what a present state is one of an initial state, a proportional steady state, and a later state, controlling the pumping rate, which is obtained by adding the flow rate corresponding to the volume loss due to the compression of the hydraulic fluid thereto, to control the ram in the initial state, and controlling the pumping rate, which is obtained by subtracting the flow rate corresponding to volume recovery of the hydraulic fluid due to the relief of compression of the hydraulic fluid therefrom, to control the ram in the later state.

A method of controlling a hydraulic system, the hydraulic system including a ram cylinder unit having a cylinder and a ram, and a hydraulic pump and a reservoir used to supply hydraulic fluid to the cylinder, and hydraulically driving the ram using the hydraulic fluid so as to move against a specific load, the method includes determining what a present state is one of an initial state, a proportional steady state, and a later state, controlling the pumping rate, which is obtained by adding the flow rate corresponding to the volume loss due to the compression of the hydraulic fluid thereto, to control the ram in the initial state, and controlling the pumping rate, which is obtained by subtracting the flow rate corresponding to volume recovery of the hydraulic fluid due to the relief of compression of the hydraulic fluid therefrom, to control the ram in the later state.