Sundstrand Corporation

Brent A Klopfenstein

Jeffrey D Metcalf

David J Lang

A dual hydraulic motor system where motor wobblers are mechanically linked and the motor outputs are torque summed, is controlled by a three position dual valve assembly. Each valve assembly is controlled by pilot pistons that are mechanically linked to provide three functions, one being normal operation, a second where one motor must be shut-off and its load on the system is minimized and the third where both motors are shut-off and significant drag is then provided. These functions are implemented by a separate spool in each valve which has three independent stable positions.

Three position dual failure shut-off valve system

A shock absorbing overtravel stop apparatus which includes a rotatable drive shaft 10, a screw shaft 15 driven by the drive shaft 10, and a nonrotatable travelling nut 30 threaded on and moveable axially along the screw shaft 15. At one end 28 of the screw shaft 15, the apparatus is provided with a rotating stop 38 and a stationery stop 40. At the other end 20 of the screw shaft 15, there is provided a bearing housing 21, journalling the screw shaft 15 for rotation and mounting the screw shaft for axial movement along the axis. The travelling nut 30 is moveable in one direction to engage the stops 38, 40 whereupon the rotary motion of the screw shaft 15 is terminated. The travelling nut 30 is also moveable in the other direction into contact with the bearing housing 21 to exert an axial force upon the screw shaft 15 such that the screw shaft 15 moves axially to engage the stops 38, 40 whereupon the rotary motion of the screw shaft 15 is terminated. The screw shaft 15 of the present invention acts as a torsion shock absorber upon the termination of the rotary motion of the screw shaft 15 by the stops 38, 40.

Shock absorbing overtravel stop

A no-back mechanism including a rotatable screw shaft 16, rotatable drive element 70 on the screw shaft 16, a limited lost motion connection 72 between the screw shaft 16 and the drive element 70, a thrust plate 28 on the screw shaft 16, first and second friction discs 30, 32 sandwiching the thrust plate 28 and being journaled by bearings 38, 40 for rotation with the thrust plate 28, first and second one way clutches 54, 56 respectively associated with the first and second friction discs 30, 32 for respectively allowing the first friction disc 30 to rotate in one direction but not the other and for allowing the second friction disc 32 to rotate in the other direction but not in the first direction, a ratchet ring 86, 88 surrounding the screw shaft 16, first and second oppositely directed pawls 104, 106 carried by the screw shaft 16 and engageable with the ratchet ring 86, 88 for preventing relative motion between the screw shaft 16 and the ratchet ring 86, 88 in the direction the associated pawl 104, 106 is directed, and a pawl operator 116 carried by the drive element 70 and operable to disengage one or the other of the pawls 104, 106 from the ratchet ring 86, 88, dependent upon the direction of rotation of the drive element 70 as the drive element 70 moves relative to the screw shaft 16 through the limited lost motion connection 72.

No-back mechanism

A non-jamming ballscrew actuator system which includes an inner screw, an intermediate ballscrew internally threaded on the inner screw, and an outer ballscrew nut rotatably mounted about the ballscrew. An actuator is operatively associated with a load to be actuated and connected to the inner screw for axial movement therewith. A drive rotates the ballscrew nut to axially move the ballscrew. A first brake prevents rotation of the ballscrew, and a second brake prevents rotation of the inner screw. In the event of jamming between the ballscrew and ballscrew nut, the first brake is released to allow the ballscrew to threadingly drive the inner screw and, thereby, move the actuator. In the event of failure of the drive, the second brake is released to allow reaction movement of the actuator means in response to load forces.

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Rockford, IL, United States of America

Brent A Klopfenstein