Abstract: A hydraulic actuator comprises piston that divides the interior into a piston chamber and a rod chamber and a valve disc assembly to regulate flow of hydraulic fluid between the piston chamber and the rod chamber through a passage in the piston. The disc valve assembly includes a washer, a valve pack that includes at least one flexible disc valve, and a spacer arrangement spacing the valve pack apart from the washer. During operation, the valve pack flexes to open and close the passage. The spacer arrangement includes a first support point supporting the valve pack relative to the washer and at least one second support point spaced apart from the flexible portion of the disc valve pack. In the open position, the valve pack engages the second support point to reduce stress build-up at the first support point, thereby reducing work fatigue of the valve disc and extending the useful life of the hydraulic actuator.

Abstract: A hydraulic damper includes an internal accumulator for storing and dissipating energy resulting from a fluid pressure spike inside the damper. A housing is mounted on a piston rod above a reciprocable piston. A compressible medium is stored in the housing. A valve assembly controls the flow of fluid into and out of the accumulator. When a sudden fluid pressure rise occurs, the medium compresses to store the energy. When the pressure rise dissipates, fluid exits the accumulator as the medium expands.

Abstract: A semi-active hydraulic damper includes a solenoid valve assembly for controlling fluid flow through a bypass channel. A blow-off valve assembly is provided in series with the solenoid valve assembly to provide low-level damping when the bypass channel is open.

Abstract: A compact direct drive system for an extensible and retractable antenna assembly uses a one-piece antenna and no threads or gears. The one-piece antenna is supported so as to slide axially up and down, but is restrained against turning. It runs through the hollow drive shaft of a coaxially supported electric motor. Traction rollers supported on skewed shafts fixed to the end of the drive shaft drive the antenna up and down.

Abstract: A molded piston for a shock absorber is formed as a cylindrical member having a central, axial opening for receiving a piston rod. A plurality of unrestricted axial openings are provided in the piston radially outbound of the central opening and aligned substantially parallel to the axis of the piston to serve as primary flow passages. A plurality of axial grooves are provided on the circumference of the piston to serve as secondary flow passages. A flexible, circumferential valving ring is integrally molded at one end of the piston for permitting only one-way flow of fluid through the secondary flow passages as the piston reciprocates in an inner cylinder.

Abstract: A vortex valving assembly for a hydraulic damper is adaptable for use in both a piston and a cylinder end. A generator plate includes a plurality of upstanding, arcuate vanes for imparting a vortex to passing fluid and directing the fluid to a central opening. A control plate having a plurality of openings is stacked adjacent the generator plate to control the entry and exit of fluid from the control plate during reciprocation of the piston.