Abstract: Fluid actuator includes shear pins or threaded fasteners between a rod gland and a rod gland bearing which cause the rod gland bearing to separate from the rod gland in response to a predetermined jam clearance force being applied to the rod gland bearing upon engagement of a rod deformation either exteriorly or interiorly of the actuator with the rod gland bearing to clear such rod deformation. The shear pins or threaded fasteners are sized to withstand the usual internal pressures acting on the rod gland bearing. However, whenever a piston rod deformation engages the rod gland bearing, the entire actuator force is available to shear the shear pins or threaded fasteners which frees the rod gland bearing to allow movement of the rod gland bearing with the piston rod to clear the rod deformation. A single retainer plate may be used to retain both a plurality of headed shear pins and a retaining wire for the rod gland.

Abstract: A fluid actuator characterized by a linear variable differential transformer (LVDT) feedback mechanism driven off the actuator screw shaft for indicating actuator position. A protective clutch mechanism prevents possible damage to the LVDT or actuator in the event that the actuator stroke exceeds the design stroke of the LVDT.

Abstract: Fluid actuator includes a piston rod comprised of a wound filamentary composite structure to provide an extremely light weight, relatively low cost, envelope efficient design. Attached to the piston rod are one or more non-integral piston heads which are preloaded against one or more ramp surfaces on the exterior of said piston rod. A pair of oppositely facing ramp surfaces may be formed on the piston rod by interspersing filler means between the piston rod fiber layers. Another ramp area may be formed by providing an external groove in the piston rod which is engaged by longitudinally split support shoes that provide an attachment surface for a detachable piston head. An internal ramp may also be provided on the inner diameter of the piston rod adjacent the axial outer end thereof for mating engagement by a conically ramped exterior surface on an internal metal stud used to attach a rod end assembly to the axial outer end of the piston rod.

Abstract: A fluid actuator characterized by a feedback mechanism for indicating actuator position. The feedback mechanism is driven by the actuator screw shaft, whereby the movements of the feedback mechanism are proportional to the rate and position of the actuator movements. The feedback mechanism and actuator movements may be synchronized so that the extreme end positions of the feedback mechanism will correspond to the fully retracted and extended positions of the actuator. A stroke limiting mechanism may also be provided for preventing the actuator from overstroking the feedback mechanism in the event that they are not properly synchronized.

Abstract: Dual tandem composite cylinder assembly includes a cylinder having circumferential or hoop stress windings surrounding a pair of hydraulic chambers in series to react the circumferential loads and prevent diametrical expansion of the hydraulic chambers. Longitudinal tension windings extend over substantially the entire length of the cylinder outwardly of the circumferential windings to react the axial loads which the cylinder must contain. Compressive cylinder composite windings are also provided for carrying compressive loads generated within the cylinder. The hydraulic chambers are desirably lined with removable liner members to facilitate changing of seals and refurbishment of the cylinder.

Abstract: Fluid actuator includes a composite cylinder having circumferential hoop stress windings wrapped about a liner member forming the piston chamber wall, and longitudinal tension windings extending from the outboard end of the cylinder along one side thereof and around the inboard end of the cylinder to the other side and back to the outboard end where they are secured to the cylinder. A compression column of composite material may be provided between a cylinder end wall and a permanent structure mount at the inboard end of the cylinder to extend the length of the cylinder to accommodate a tail stock on the piston of a pressure balanced actuator.

Abstract: Multiple drive paths are provided between the valve plunger and force motor of a direct drive valve and force motor assembly whereby should one of the drive paths fail, the force motor can still be used to drive the valve plunger through another drive path. One of the drive paths consists of a drive shaft having one end drivingly connected to an eccentric on the motor output shaft and the other end connected to the end of the valve plunger remote from the motor output shaft. The drive shaft is desirably provided with an enlarged head portion having a flat annular surface on the axial inner end thereof in close proximity to a corresponding flat end face on the end of the valve plunger closest to the motor output shaft, whereby should the valve plunger break, the drive shaft will hold the valve plunger together and allow for degraded valve performance.

Abstract: An actuator system characterized by parallel connected flow regulator valves for controlling the flow of fluid to and from the extend ends of a corresponding number of fluid actuators. Retract orifices in the fluid lines leading to the retract ends of the actuators prevent cavitation of the extend ends of the actuators under an aiding air load pulling the actuators out during extension thereof.

Abstract: Actuator includes a lock mechanism for locking the actuator against movement in one end position, and a separate lock release assembly exteriorly mounted on the side of the actuator housing. The lock release assembly includes a toggle linkage directly engageable with the movable lock part to disengage the lock when a suitable force is applied to the toggle linkage exteriorly of the actuator. A lock spring is located immediately between the movable lock part and actuator piston for resetting the lock as the actuator nears such one end position.

Abstract: A fluid actuator including a lock mechanism for locking the actuator against movement in one position and a fluid operated sequence-power valve which when actuated by fluid pressure releases the lock mechanism and then ports such fluid pressure directly to the actuator to cause movement thereof in the desired direction following release of the lock mechanism.

Abstract: A single ended hydraulic actuator requiring hydraulic pressure to extend the piston for raising the cowl door of a jet engine and the like. A preload spring device carried in the piston-rod assembly produces an extend force when the actuator is retracted and the door is closed which preloads the actuator to help eliminate fretting of the bearings and piston rod which otherwise can occur due to flight vibrations when unloaded.