A cylinder includes a cylinder tube, a first closure part, a second closure part, and a piston unit. The cylinder tube has a first tube end and a second tube end. The tube and end closure parts define a cylinder interior. The piston unit defines at least one working space in the cylinder interior. The first closure part is connected to the tube by a first peripheral laser ring weld and the second closure part is connected to the tube by a second peripheral laser ring weld. The laser ring welds each define a fluid-tight sealing plane. A peripheral sealing ring is located between each closure part and a tube inner wall at an axial distance from the associated laser ring weld seam. The peripheral sealing ring defines a pressure-separated ring section between the peripheral sealing ring and the associated laser ring weld seam.

A working cylinder has a cylinder tube, a first closure part, a second closure part and a piston unit. The first closure part is arranged on a first cylinder tube end, the second closure part is arranged on a second cylinder tube end to define a cylinder interior. The piston unit defines at least one working chamber in the cylinder interior. The piston unit slides through the first closure part. The first closure part is joined to the cylinder tube by a first peripheral laser ring weld seam and the second closure part is joined to the cylinder tube by a second peripheral laser ring weld seam. The laser ring weld seams each define a fluid-tight sealing plane. A method for producing the working cylinder is provided.

A working cylinder has a cylinder tube, a first closure part, a second closure part and a piston unit. The first closure part is arranged at a first cylinder tube end and the second closure part is arranged at a second cylinder tube end, the cylinder tube and the first and second closure parts define a cylinder interior. The piston unit defines at least one working chamber in the cylinder interior. The piston unit slidably passes through the first closure part. The first closure part us joined to the cylinder tube in a positive-locking manner by a first circumferential laser ring weld seam. The second closure part is joined to the cylinder tube in a positive-locking manner by a second circumferential laser ring weld seam, and each of the laser ring weld seams define a fluid-tight sealing plane. At least one of the closure parts has an axially opening that is a circumferential concave receiving contour in which the cylinder tube engages. The receiving contour radially overlaps the cylinder tube, and a ring weld seam inclination angle thereof is 110 to 160 degrees.

An actuation device for a human-powered vehicle comprises a base member, a movable member, and an actuator. The movable member is movably provided on the base member. The actuator is configured to be actuated by stimulation including at least one of electric stimulation and heat stimulation so as to move the movable member relative to the base member in a first direction by pulling the movable member.

Disclosed is a method for repairing a piston-cylinder unit within a working machine or within an attachment, wherein a connection of the piston rod with the machine or implement structure is released and the piston rod, the piston and at least one bearing head is jointly removed from the cylinder housing as an assembly and replaced by a premounted substitute assembly consisting of piston rod, piston and at least one bearing head.

Disclosed is a method for repairing a piston-cylinder unit within a working machine or within an attachment, wherein a connection of the piston rod with the machine or implement structure is released and the piston rod, the piston and at least one bearing head is jointly removed from the cylinder housing as an assembly and replaced by a premounted substitute assembly consisting of piston rod, piston and at least one bearing head.

An apparatus and method provide a barrier in the cooling airflow of a component of a computing device that, when the barrier is extended, impedes the airflow, thereby diverting excess cooling airflow from the component to a different component with a different flow path. In response to increased pressure from the airflow, the barrier retracts to permit a greater airflow. Embodiments respond to an increase or decrease in airflow without requiring additional control input and include barriers that deform or pivot in response to increased pressure to permit greater airflow.

An actuator has a housing (14), a pyrotechnic charge (17) and a piston (11) which transitions into a pin (12) which in the initial state projects out of the housing (14) and upon ignition of the pyrotechnic charge (17) is retracted at least partially into the housing (14). According to the invention, the piston-pin combination consists of a main body (10) which is made of plastic and has a reinforcing element (13) in the region of the pin (12). The reinforcing element (13) has the shape of a sleeve or tube and surrounds the pin (12). It is form-fittingly connected to the pin (12), for example by the sleeve-like or tubular reinforcing element (13) having a shape (22) for reducing the inner cross-section.

A piston and cylinder assembly structured to reduce breakaway friction (stiction) upon movement of the piston within the cylinder. The assembly includes a cylinder housing, a piston having a piston crown with a top face and one or more peripheral grooves, and a sealing ring positioned on the piston in each of the one or more peripheral grooves. The piston crown incorporates one or more passageways extending from a space above the piston to a location within the peripheral groove inside of (behind) the sealing ring. An increase in a volume of fluid in the chamber above the piston directs fluid through the passageways into the peripheral groove, thereby pressing the sealing ring against the cylinder wall. A double acting piston embodiment uses at least two sealing rings positioned within at least two grooves, each with associated fluid flow passageways into the grooves behind the sealing rings.

A valve assembly with at least two valve modules is described, wherein the valve modules are arranged one beside the other in a line-up direction. The valve assembly also comprises an indicating device for displaying a state of the valve modules and/or of the valve assembly and/or of a component connected to the valve assembly. In the line-up direction the indicating device continuously extends over all valve modules.