Patent attributes
A screw actuator comprises a nut having an internal helical formation and a screw having an external helical formation and rotatably received within the nut, relative rotational movement of the nut and screw causing axial movement of one of the nut and screw relative to the other of the nut and screw. The actuator further comprises a lubricant reservoir and a lubricant pressuriser for pressurising lubricant within the lubricant reservoir. A lubricant receiving chamber is formed in the nut. The screw extends through the lubricant receiving chamber. A lubricant supply passage fluidly connects the lubricant reservoir and the lubricant receiving chamber. A valve controls the flow of lubricant between the lubricant reservoir and the lubricant receiving chamber. A lubricant supply piston is received in the lubricant receiving chamber and is mounted on the external helical formation of the screw.
