Aspects of the present disclosure relate to fail open or fail close actuator assemblies and related methods for valve systems. In one implementation, an actuator assembly for valves includes an outer housing that includes an inner surface at least partially defining an internal volume. The actuator assembly includes one or more first fluid openings formed in the outer housing, one or more second fluid openings formed in the outer housing, and one or more ambient openings formed in the outer housing. The actuator assembly includes a valve stem disposed at least partially in the internal volume, and a first piston disposed in the internal volume and coupled to the valve stem. The actuator assembly includes a second piston disposed in the internal volume and disposed about the valve stem.

A hydraulic cylinder comprising a cylinder, a piston element movably guided in the cylinder in a working direction and comprising an active surface, and a first opening for feeding a fluid into a cylinder chamber by the active surface. A working pressure of the fluid acting on the active surface drives the piston element in the working direction. The active surface includes a first partial surface and at least one second partial surface, the cylinder chamber being divided into a first sub chamber with the first opening by the first active surface and a second partial surface with a second opening by the second partial surface, and the partial surfaces are hydraulically separated from each other at least in a selectable operating mode.

Combination linear and rotary actuators are disclosed. The linear and rotary actuators have a housing defining a cylindrical interior space and a pair of pistons located inside the cylindrical interior space. An inner bearing cylinder is provided that has spaced-apart ball bearings arranged in a helical pattern on its surface that engage with a structure having an inner surface with helical grooves therein. The structure at least indirectly engages a linear drive piston that is slidably mounted in the housing, and provides rotational movement thereto. The linear drive piston has an input shaft that has ball bearings on its surface, and is inserted inside the output shaft of a revolution piston that has an inner surface with linear grooves. The actuators use hydrostatically charged integral bearing races that activate during operation to reduce friction. Combination linear and rotary actuators with double actuation output shafts are also provided.

A method of controlling a hydraulic actuator, wherein the hydraulic actuator includes a linear double-acting output member, and at least three working chambers in fluid connection with the output member, the working chambers having respective effective areas with a non-binary relationship; wherein the method includes selectively fluidly connecting each working chamber to either a high-pressure side or a low-pressure side to provide a plurality of discrete pressurization states of the hydraulic actuator; determining at least one of the pressurization states as a prevented pressurization state; and transitioning between a plurality of allowed pressurization states among the pressurization states while preventing transition to the at least one prevented pressurization state. A hydraulic actuator and a hydraulic system are also provided.

The disclosure relates to a hydraulic control block for controlling a pressure medium supply of a hydraulic cylinder of a hydraulic spindle. The hydraulic control block includes a generic hydraulic switching structure electively configurable in each of a plurality of specific hydraulic switching structures, each of the plurality of specific hydraulic switching structures having a respective hydraulic cylinder with a number of piston areas which differs from a number of piston areas in the respective hydraulic cylinders of each of the other of the plurality of specific hydraulic switching structures.

A saddle clamp for a bicycle includes a rail clamp, and a first and a second post clamp. The rail clamp includes a first rail clamp body configured to engage at least a portion of a first rail of a bicycle saddle, and a second rail clamp body configured to engage at least a portion of a second rail of the bicycle saddle, wherein the first and second rail clamp bodies are configured to cooperate to urge the first and second rails towards each other. Each post clamp is configured to engage a bicycle seat post, with the first and second post clamps disposed between the first and second rail clamp bodies, wherein the first and second post clamps are configured to exert a compressive force on the bicycle seat post in response to the first and second rail clamp bodies urging the first and second rails towards each other.

Combination linear and rotary actuators are disclosed. The linear and rotary actuators have a housing defining a cylindrical interior space and a pair of pistons located inside the cylindrical interior space. An inner bearing cylinder is provided that has spaced-apart ball bearings arranged in a helical pattern on its surface that engage with a structure having an inner surface with helical grooves therein. The structure at least indirectly engages a linear drive piston that is slidably mounted in the housing, and provides rotational movement thereto. The linear drive piston has an input shaft that has ball bearings on its surface, and is inserted inside the output shaft of a revolution piston that has an inner surface with linear grooves. The actuators use hydrostatically charged integral bearing races that activate during operation to reduce friction. Combination linear and rotary actuators with double actuation output shafts are also provided.

An actuator control arrangement includes a hydraulic actuator having a housing and a piston rod axially moveable within the housing, a stop disposed within the housing to limit the extent of movement of the piston rod into the housing, and a solenoid valve arranged between a pressure source and the actuator. The solenoid valve is switchable between a first mode and a second mode in response to an electric control signal, wherein, in the first mode, the solenoid valve creates a fluid flow path from the pressure source to the actuator so as to locate the stop in its neutral position and in the second mode, the solenoid valve creates a fluid flow path to release pressure from the actuator to permit the stop to move to its retracted position. In the event of electrical failure, the stop will set the actuator to its neutral position.

A height-adjustable seat post includes a lower tube having a top open end and a bottom open end, an upper tube having a top end and a bottom end, and a saddle clamp removably coupled to the upper tube. The top end of the upper tube is configured to be received through the bottom open end of the lower tube and extend beyond the top open end, and, when the saddle clamp is removed from the upper tube, the top end of the upper tube is configured to pass through the bottom open end of the lower tube.

A fluid pressure cylinder includes a first cylinder portion and a second cylinder portion disposed in parallel, and a supply-and-discharge port. The first cylinder portion is partitioned by a first piston into a head-side first accumulation chamber and a rod-side second accumulation chamber. The second cylinder portion is partitioned by a second piston into a head-side release chamber and a rod-side drive chamber. Pressurized fluid is supplied to and discharged from the second accumulation chamber and the drive chamber through the supply-and-discharge port. An end of a first piston rod connected to the first piston and an end of a second piston rod connected to the second piston are connected to each other. The first piston includes a communication switching valve switching communication between the first accumulation chamber and the second accumulation chamber, between enabled and disabled.