Emergency collective actuator and method for a helicopter

Patent metadata

Field	Value
Publication number	US-9789958-B2
Application number	US-201615345273-A
Country	US
Kind code	B2
Filing date	Nov 7, 2016
Priority date	Nov 24, 2009
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A helicopter includes a rotor system having a rotor with an adjustable pitch that is controlled at least in part by a pilot using a collective control and which helicopter generates a Low RPM signal that is indicative of a threshold low rotational speed of the rotor. An actuator arrangement can move the collective control by exerting a force on the collective control such that the pilot is able to overcome the actuator force but which otherwise can move the collective control from a current operational position toward a minimum pitch position. A clutch can co-rotate with a motor to serve in transferring the actuation force to reduce the adjustable pitch and can slip relative to the actuator shaft assembly responsive to an application of a counterforce applied by the pilot to the collective control such that the counterforce overcomes the actuation force.

First claim

What is claimed is:

1. An apparatus for use with a helicopter including a rotor system having a main rotor with an adjustable pitch that is controlled at least in part by a pilot using a collective control and which main rotor is driven by an engine, said apparatus comprising:
an actuator arrangement that is configured to change the adjustable pitch by exerting an actuation force on the collective control, which actuation force can be overcome by the pilot using the collective control, and which actuation force otherwise biases the adjustable pitch toward a minimum collective pitch position; and
a control arrangement that is configured to monitor an engine RPM of the engine and to respond to a low RPM engine condition by activating the actuator arrangement to exert the actuation force for a predetermined period of time.

2. The apparatus of claim 1 wherein said control arrangement includes a comparator which compares the engine RPM to an engine RPM threshold during the predetermined period of time to respond to the low RPM engine condition.

3. The apparatus of claim 2 wherein the actuator arrangement includes a motor to apply the actuation force and the control arrangement, during the predetermined period of time, is configured to turn the motor on if the motor is off and to maintain the motor in an on state if the motor is already on responsive to detecting the low RPM engine condition.

4. The apparatus of claim 3 wherein the control arrangement is configured to turn off the motor responsive to an inactive state of the low RPM engine condition during the predetermined period of time.

5. The apparatus of claim 1 wherein the control arrangement is configured to monitor the engine RPM in a continuous loop and to initiate the predetermined period of time responsive to detecting the low RPM engine condition.

6. The apparatus of claim 5 wherein the control arrangement, responsive to detecting the low RPM engine condition, is further configured to thereafter reconfirm the low RPM engine condition before causing the actuator arrangement to exert the actuation force.

7. The apparatus of claim 1 wherein said control arrangement is further configured for entering a lockout interval immediately following said predetermined period of time during which lockout interval the low RPM engine condition is disabled from activating the actuator arrangement.

8. The apparatus of claim 1 wherein said predetermined period of time is in a range from 1 second to 10 seconds.

9. The apparatus of claim 1 configured to apply said actuation force within 1 millisecond of detecting the low RPM engine condition.

10. The apparatus of claim 1 wherein said collective control includes an arm that is pivotable to change the adjustable pitch of the rotor and said arm includes an arm length extending from a pivot end to a distal end that is directly engaged by the pilot and wherein said actuator arrangement is connected to an intermediate position along the arm length to apply said actuation force directly to the arm.

11. The apparatus of claim 10 positioned below said collective control such that said force pulls on said collective control from said intermediate position.

12. The apparatus of claim 11 wherein said actuator arrangement includes a cable having one end that is attached to the intermediate position of the arm length for pulling on the collective control.

13. The apparatus of claim 12 wherein the actuator arrangement includes an electric motor for applying said force to the cable by rotating in a given direction.

14. The apparatus of claim 1 wherein said collective control includes an arm that is pivotable to change the adjustable pitch of the rotor and a counterbalance spring that is configured as part of a counterbalance linkage to apply a resilient bias to the collective arm and wherein said actuator arrangement is configured to apply said force to said counterbalance linkage in a way that compresses the counterbalance spring for moving the collective control to the minimum pitch position.

15. The apparatus of claim 14 wherein said actuator arrangement further includes at least one lever arm having a first end that is pivotally attached to the helicopter and a second, opposing end that is moved responsive to an electric motor such that an intermediate portion of the lever arm applies said force.

16. The apparatus of claim 1 wherein said control arrangement includes a pilot actuatable switch that is switchable by the pilot to selectively disable the application of said force to the collective.

17. The apparatus of claim 1 wherein said control arrangement includes an arrangement for using at least a detected altitude of the helicopter above a surface of the ground to disable the application of said force below a predetermined altitude.

18. The apparatus of claim 1 wherein said control arrangement is configured for disabling the application of said force based on a detected altitude of the helicopter in combination with a detected airspeed of the helicopter.

19. The apparatus of claim 1 wherein said control arrangement is configured for disabling the application of said force within at least one predetermined unsafe region of a height-velocity diagram for the helicopter.

Assignees

• Merlin Technology Inc

Inventors

• Mercer John E
• Marvin Mark H

Classifications

• B64C27/006

  Safety devices · CPC title

• B64C27/59

  mechanical · CPC title

• B64C27/57 Primary

  automatic or condition responsive, e.g. responsive to rotor speed, torque or thrust · CPC title

• B64C27/04

  Helicopters · CPC title