Abstract: Disclosed herein is a hydraulic to pneumatic power transfer unit which converts a high pressure oil flow into a flow of high pressure air by means of three stages of piston pumps and characterized by a first stage having a pair of linked pistons of substantially equal size both supplying air to a second stage piston which is directly linked to a third stage piston so that the pair of second and third stage pistons work alternately with the pair of first stage pistons and the linkage between each pair of pistons actuate spool valves which control the motion of the other pair of pistons.A further improvement is also disclosed in which an internal oil reservoir and a swash-plate pump is added to the system so that it may be powered by a rotating shaft instead of a flow of oil. In addition, the pulses of oil produced by the swash-plate pump directly control the piston pairs without the need for spool valves.

Abstract: Apparatus and method for hydraulic actuation via multiple synchronized hydraulic motors with air purging, synchronizing, and force limiting features.

Abstract: A closed center four-way poppet actuator control device is incorporated into a pneumatic actuation system for controlling the movement of flight surfaces. The closed center four-way poppet actuator control device has a housing, a pair of two-way poppet valves in the housing, a rocker arm assembly mounted on the housing and connected to the pair of two-way poppet valves, and a diaphragm assembly also mounted in the housing and in contact with the two-way valves. A torque motor-driver assembly connected to the diaphragm assembly actuates the two-way valves as determined by control signals. The rocker arm causes the two-way valves to function oppositely each other: one allows high pressure gas to be input to a lobe motor actuator while the other allows gas to be output from the lobe motor actuator. Each two-way valve has a cylindrical poppet valve for inletting the gas to the actuator and a disk poppet valve for outputting the gas from the actuator to a vent.

Abstract: A torque limiting clutch having a torque limit which is easily calibrated and relatively constant throughout the service life of the clutch. The clutch includes a pair of rotatable members which are rotatably coupled by resilient friction members yieldably engaging one of the pair of members and securing to the other of the pair of members. The friction elements are configured to achieve substantially uniform friction force and wear along their friction surfaces. According to one embodiment of the invention standard commercial snap rings may be employed as the friction elements.