Differentially coupled dual channel actuator

• US 4,834,319 A
• Filed: 10/05/1987
• Issued: 05/30/1989
• Est. Priority Date: 10/05/1987
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Ewy, Robert J., Burrell, Gary L.
• Primary Examiner(s): BAREFOOT, GALEN L
• Application Number:
  US07/104,683
• Time in Patent Office: 603 Days
• Field of Search: 244/75 R, 244/76 R, 244/220, 244/221, 244/224, 244/226, 244/227, 244/228, 244/230, 244/231, 244/196, 244/197, 74/661, 74/675, 74/326, 74/799, 74/665 B
• US Class Current: 244/99.9
• CPC Class Codes: B64C 13/34 using toothed gearing
• CPC Class Codes: B64C 13/341 having duplication or stand-by provisions
• CPC Class Codes: B64C 13/343 overriding of personal controls; with automatic return to inoperative position
• CPC Class Codes: G05G 11/00 Manually-actuated control mechanisms provided with two or more controlling members co-operating with one single controlled member
• CPC Class Codes: Y10T 74/2063 Stops

Abstract

A dual channel actuator for regulating control surfaces of an aircraft such as a helicopter. Primary and secondary channels are coupled by a differential gear. An internal stop in the differential gear limits the short term range of travel or authority of the primary channel. The secondary channel allows extended long term authority by recentering the reference point about which the rotational range of the primary channel is determined. A servo motor and primary input gear of the differential gear comprise the primary channel. A second servo motor and secondary input gear comprise the secondary channel. The reference point comprises a stop pin coupled with said differential gear.

Claims

1. An aircraft control system having a dual channel actuator for regulating control surfaces of the aircraft, said actuator comprising:

a primary motor;

means coupling said primary motor with said control surfaces, wherein activation of said primary motor drives said coupling means and allows regulation of said control surfaces;

means coupled with said coupling means for limiting movement of said coupling means in response to activation of said primary motor, said movement being limited to a preselected range about a reference point; and

means coupled with said limiting means for positioning said reference point to allow continued movement of said coupling means when a limit of said range is reached whereby said actuator has a limited short term and an extended long term range of travel.

2. The invention of claim 1, wherein said positioning means comprises a secondary motor and said coupling means comprises a differential gear coupled with said primary and secondary motors and said control surfaces.

3. The invention of claim 3, wherein said differential gear comprises a primary input gear coupled with said primary motor, a secondary input gear coupled with said secondary motor, and an output gear coupled with said primary and secondary input gears and said control surfaces, wherein said primary and secondary input gears differentially drive said output gear.

4. The invention of claim 3, wherein said limiting means is coupled with said differential gear and limits the rotation of said output gear to said preselected range about said reference point.

5. The invention of claim 4, wherein said limiting means and reference point comprise a pin coupled with said primary input gear, said pin engagable with said output gear to prevent rotation of said output gear when said range limit is reached.

6. The invention of claim 3, wherein said primary and secondary input gears comprise end gears respectively coupled with said primary and secondary motors and side gears coupled with said end gears.

7. The invention of claim 6, wherein said side gears are oriented in spaced apart, facing relationship and wherein said output gear comprises pinion gears mounted on opposite ends of a spider member and positioned between said side gears, said spider member being coupled with a control rod whereby activation of said primary motor regulates movement of said control rod.

8. An aircraft control system having a dual channel actuator for regulating control surfaces of the aircraft, said actuator comprising:

primary and secondary motors;

a differential gear coupling said primary and secondary motors;

said differential gear comprising a primary input gear driven by said primary motor, a secondary input gear driven by said secondary motor, and an output gear differentially driven by said primary and secondary input gears;

an output shaft coupling said output gear and said control surfaces; and

means coupled with said differential gear for limiting movement of said output gear to a preselected range about a reference point in response to movement of said primary input gear, wherein movement of said secondary input gear causes relative movement of said reference point to allow continued movement of said primary input gear when the end of said preselected range is reached whereby said actuator has a limited short term and an extended long term range of travel.

9. The invention of claim 8, wherein said limiting means and said reference point comprise a stop pin coupled with said primary input gear and engageable with said output gear for limiting movement of said primary input gear to said range.

10. The invention of claim 9, wherein said output gear comprises pinion gears mounted on opposite ends of a spider member and positioned between said primary and secondary input gears.

11. The invention of claim 10, wherein said spider member is coupled with said output shaft.

12. The invention of claim 10, wherein said primary and secondary output gears comprise end gears respectively coupled with said primary and secondary motors and side gears coupled with said end gears.

13. A method for limiting the short term authority of an autopilot system having a dual channel actuator while allowing for an extended long term authority, said method comprising the steps of:

driving an output shaft of said actuator by movement of a primary channel of said actuator;

limiting the short term movement of said primary channel to a preselected range about a reference point; and

sensing when a limit of said range has been reached and after a preselected time then activating a secondary channel of said actuator to move said reference point in the direction of said range limit to allow continued movement of said primary channel, whereby the short term range of movement is limited while the extended long term range of movement is maintained.

14. The method of claim 13, including the step of coupling said primary and secondary channels with a differential gear comprising primary and secondary input gears and an output gear.

15. The method of claim 14, wherein said primary channel comprises a primary motor and said primary input gear and said secondary channel comprises a secondary motor and said secondary input gear, said input gears being differentially coupled with said output gear and said output gear being coupled with said output shaft.

16. The method of claim 14, wherein said reference point comprises a stop pin coupled with said differential gear.