Fail safe redundant actuator

• US 4,179,944 A
• Filed: 06/27/1977
• Issued: 12/25/1979
• Est. Priority Date: 06/27/1977
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Conner, Gary E.
• Primary Examiner(s): McCall, James T.
• Application Number:
  US05/810,149
• Time in Patent Office: 911 Days
• Field of Search: 74/89.15, 74/424.8 R, 74/424.8 A, 74/110, 74/89.15, 188/78, 188/343, 192/141, 192/143, 192/150, 92/31, 92/32, 92/33
• US Class Current: 74/89.26
• CPC Class Codes: B64C 13/341 having duplication or stand-by provisions
• CPC Class Codes: F16H 2025/2075 Coaxial drive motors
• CPC Class Codes: F16H 25/205 comprising alternate power paths, e.g. for fail safe back-up
• CPC Class Codes: H02K 26/00 Machines adapted to function as torque motors, i.e. to exert a torque when stalled
• CPC Class Codes: H02K 7/06 Means for converting reciprocating motion into rotary motion or vice versa
• CPC Class Codes: Y10T 74/186 Alternate power path operable on failure of primary

Abstract

An electromechanical actuator is provided which is capable of disconnecting the output shaft and the drive mechanisms in such a way that, in the event of either a rotational or translational failure during operation, the output shaft can be effectively freed in such a manner that it will not resist the motion produced by other actuators which have not failed.

Claims

1. A fail-safe actuator comprising:

(a) an output shaft;

(b) a guide shaft receiving said output shaft;

(c) first delatchable coupling means connecting said output shaft and said guide shaft;

(d) power screw means for driving said guide shaft in a longitudinal direction, said power screw means comprising screw means comprising screw and nut components;

(e) rotor shaft means receiving said nut component;

(f) connecting means connecting said nut component to said rotor shaft means in rotationally fixed, translationally free relationship therewith;

(g) second delatchable coupling means preventing translational motion of said ball nut means within said rotor shaft;

(h) first and second reversable drive means for causing rotation of said rotor shaft, said first drive means being adapted to rotate said rotor means in a clockwise direction in normal operation and said second drive means being adapted to rotate said rotor shaft in a counter-clockwise direction in normal operation;

(i) means for delatching said second delatchable coupling means when either of said motors are operated in the reverse direction from normal operation; and

(j) means directing said ball nut into delatching engagement with said first delatching means after said second delatching means is delatched.

2. A fail-safe actuator comprising:

(a) an output shaft for connecting said actuator to a load;

(b) a guide shaft receiving said output shaft in sliding relationship therewith;

(c) first delatchable coupling means connecting said output shaft to said guide shaft;

(d) reversible drive means in longitudinal driving relationship to said guide shaft for extending and retracting said drive shaft;

(e) second delatchable coupling means for disengaging said drive means from said drive shaft;

(f) means for delatching said first delatchable coupling means; and

(g) means for delatching said second delatchable coupling means.