A hydraulic device having: a plurality of main piston-cylinder arrangements, each of the respective pistons having a fixed stroke length and configured for axial reciprocation within their respective cylinder; a plurality of flow control valves for switching between a lockdown state and an unlocked state of one or more of the plurality of main piston cylinder arrangements during operation of the hydraulic device; and one or more control valves for directing the plurality of flow control valves between their respective unlock and lock positions.

A piston, in particular for a gear-change selector, including a piston body with a piston skirt and with a piston end face which can be pressurised with a working fluid. The piston includes a first sealing portion and a second sealing portion. The piston body and the first sealing portion have mutually complementary geometries so that they form a first vent channel. The first vent channel is arranged in a hydraulic series circuit with the second sealing portion. The second sealing portion prevents venting up to a first pressure and allows this above the first pressure. The invention furthermore concerns a gear-change selector and a gearshift for a vehicle.

A piston, in particular for a gear-change selector, including a piston body with a piston skirt and with a piston end face which can be pressurised with a working fluid. The piston includes a first sealing portion and a second sealing portion. The piston body and the first sealing portion have mutually complementary geometries so that they form a first vent channel. The first vent channel is arranged in a hydraulic series circuit with the second sealing portion. The second sealing portion prevents venting up to a first pressure and allows this above the first pressure. The invention furthermore concerns a gear-change selector and a gearshift for a vehicle.

A cover for a rod end of an actuator comprises a mounting collar for surrounding and mounting to a portion of the rod end. The collar is deformable such that it may be mounted over a rod eye mounted to the rod end. The cover further comprises a shield extending from the collar and shaped such that when attached to the rod end the shield shields a portion of rod end to prevent fluid or foreign object ingress to the rod end.

An assembly is provided for an aircraft. This aircraft assembly includes an aircraft control surface and a hydraulic actuator. The hydraulic actuator includes a housing and a piston within the housing. The housing is formed integral with the aircraft control surface.

A centering apparatus for bi-directionally pivotable hopper doors. The apparatus is coupled between a frame of a hopper car and a bell crank of a hopper door. The apparatus includes a housing with a piston extending from one end. An end of the piston within the housing includes a piston head. A pair of coil springs are disposed within the housing on opposite sides of the piston head and counteract one another to bias the piston head toward the center of the housing and thus bias the hopper door toward a closed state. In a second configuration the apparatus includes a double-acting actuator with a pair of independent piston assemblies. An actuation system coupled to the actuator maintains the actuator and an associated hopper door in a closed position in a normal state and returns the hopper door to the closed position upon a failure in the system.

A cylinder propping system includes a sleeve and a locking member. The sleeve includes an outer wall that defines an inner cavity and a ledge. The inner cavity is sized to receive at least a portion of a cylinder assembly therein. A first end of the outer wall is configured to hingedly couple to one end of the cylinder assembly. The ledge is spaced apart from the first end. The locking member is sized to engage with the ledge, between the ledge and a cylinder housing of the cylinder assembly, to prevent movement of the cylinder housing in at least one direction along a central axis of the sleeve.

A cylinder propping system includes a sleeve and a locking member. The sleeve includes an outer wall that defines an inner cavity and a ledge. The inner cavity is sized to receive at least a portion of a cylinder assembly therein. A first end of the outer wall is configured to hingedly couple to one end of the cylinder assembly. The ledge is spaced apart from the first end. The locking member is sized to engage with the ledge, between the ledge and a cylinder housing of the cylinder assembly, to prevent movement of the cylinder housing in at least one direction along a central axis of the sleeve.

An orthopedic screw extractor device including a shaft, an end portion about a first end of the shaft for securing to a handle, and a screw extracting tip about a second end of the shaft opposite the first end. The screw extracting tip further includes a generally frustoconical shape having a side at an angle of about 5 to 15 degrees relative to a longitudinal axis of the screw extracting tip. The screw extracting tip further includes first, second and third screw threads and first, second and third flutes circumferentially spaced about the screw extracting tip and extending across an entire length of the screw extracting tip. Each of the screw threads has a lead of about 0.07 to 0.12 inches, a pitch of about 0.02 to 0.04 inches, a thread angle of about 40 to 50 degrees, and a depth of about 0.01 to 0.02 inches.

A manufacturing method for manufacturing a cylinder tube includes a joining step of joining a tube main body and a head member by friction welding by abutting an end surface of the tube main body and a flange portion of the head member in a state in which a through hole of the tube main body and a projecting portion of the head member are fitted to each other so as to form a predetermined clearance. In the joining step, a non-contact portion of the flange portion of the head member facing the clearance is joined to the tube main body by heating the non-contact portion with friction heat generated by relative rotation between the tube main body and the head member.