Rotor pitch lock for rotary/wing aircraft

• US 6,170,779 B1
• Filed: 12/02/1998
• Issued: 01/09/2001
• Est. Priority Date: 12/02/1998
• Status: Expired due to Term

• Current Assignee: McDonnell Douglas Helicopter Co. (The Boeing Co.)
• Original Assignee: McDonnell Douglas Helicopter Co. (The Boeing Co.)
• Inventors: Nyhus, Daniel A.
• Primary Examiner(s): Barefoot, Galen L.
• Application Number:
  US09/204,627
• Time in Patent Office: 769 Days
• Field of Search: 244/17.11, 244/17.25, 244/7.R, 244/7.A, 416/140, 416/107, 416/142, 416/143, 416/153
• US Class Current: 244/7.00A
• CPC Class Codes: B64C 27/24 with rotor blades fixed in flight to act as lifting surfaces
• CPC Class Codes: B64C 27/50 Blades foldable to facilitate stowage of aircraft

Abstract

The present invention comprises an apparatus for locking the pitch axes of the rotor blades of a rotor/wing aircraft so as to form a rigid wing. In one embodiment of the present invention the rotor blades of a rotor/wing aircraft are locked to each other to form a rigid wing assembly having a common pitch axis. This wing assembly is then locked in position about its pitch axis by means of a pitch lock apparatus that engages the lower end of the pitch link of the rotor blade that is oriented at the leading edge of the fixed wing. In another embodiment each rotor is independently locked about its respective pitch axis by means of two separate pitch lock apparatus. By locking the rotor blades into a rigid assembly by means of an independent rigid pitch lock apparatus, it is possible to provide a rotor/wing aircraft having a fixed wing with more predictable and controllable response to aerodynamic forces.

Claims

1. A rotor/wing apparatus for a rotor/wing aircraft comprising:

a rotor hub rotatable about an azimuthal axis;

a first rotor blade attached to and extending radially outward from said rotor hub, said first rotor blade being pivotable about a first pitch axis extending substantially radially outward from said azimuthal axis;

a second rotor blade attached to and extending radially outward from said rotor hub, said second rotor blade being pivotable about a second pitch axis extending substantially radially outward from said azimuthal axis;

a first pitch link having a first upper end and a first lower end, said first upper end being attached to said first rotor blade eccentric of said first pitch axis, said first pitch link being moveable in a direction substantially parallel to said azimuthal axis to cause said first rotor blade to pivot about said first pivot axis;

a second pitch link having a second upper end and a second lower end, said second upper end being attached to said second rotor blade eccentric of said second pitch axis, said second pitch link being moveable in a direction substantially parallel to said azimuthal axis to cause said second rotor blade to pivot about said second pitch axis; and

a locking link having a proximal end, said proximal end including a link engaging surface, said locking link being moveable to a first position in which said link engaging surface engages one of said first and second lower ends to constrain said one of said first and second lower ends against movement parallel to said azimuthal axis, said locking link being further moveable to a second position in which said proximal end moves in a radial direction relative to said azimuthal axis to disengage said link engaging surface from said one of said first and second lower ends.

2. The rotor/wing apparatus of claim 1, further comprising:

a frame rigidly mounted to said rotor/wing aircraft

a pivot shaft rotatably mounted to said frame, said pivot shaft having first and second shaft ends; and

wherein said locking link further comprises an arm member having an attachment end attached to said first shaft end, said arm member being pivotable about said pivot shaft to move said proximal end from said first position to said second position.

3. The rotor/wing apparatus of claim 2, further comprising:

an actuator attached to said pivot shaft for causing said locking link to move from said second position to said first position.

4. The rotor/wing apparatus of claim 2, further comprising:

a bell crank arm attached to said second shaft end, said bell crank arm having a pivoting end and a free end; and

a linear actuator attached to said free end, said linear actuator adapted to rotate said pivot shaft for causing said locking link to move from said second position to said first position.

5. The rotor/wing apparatus of claim 1, further comprising;

a second locking link having a second proximal end, said second proximal end including a second link engaging surface, said second locking link being moveable to an engaged position in which said second link engaging surface engages the other of said first and second lower ends to constrain said other of said first and second lower ends against movement parallel to said azimuthal axis, said second locking link being further moveable to a disengaged position in which said second proximal end moves in a radial direction relative to said azimuthal axis to disengage said second link engaging surface from said other of said first and second lower ends.

6. The rotor/wing apparatus of claim 1, further comprising:

a housing rigidly mounted to said rotor/wing aircraft, said housing defining a bore;

wherein said locking link comprises a piston disposed within said bore, said piston being moveable linearly within said bore to move said proximal end from said first position to said second position.

7. A rotor/wing apparatus for a rotor/wing aircraft comprising:

a rotor hub rotatable about an azimuthal axis;

a first rotor blade attached to and extending radially outward from said rotor hub, said first rotor blade being pivotable about a first pitch axis extending substantially radially outward from said azimuthal axis;

a rotatable swashplate, said rotatable swashplate being selectably axially translatable and tiltable relative to said azimuthal axis;

a first pitch link having a first upper end and a first lower end, said first upper end being attached to said first rotor blade eccentric of said first pitch axis, said first lower end being operatively attached to said rotatable swashplate, said first pitch link moving in response to said rotatable swashplate to provide collective and cyclic pitch of said first rotor blade about said first pivot axis; and

a separate locking link moveable from a first position in which said locking link engages said first lower end to constrain said first pitch link against movement to a second position in which said link disengages from said first lower end to permit said first pitch link to move in response to said rotatable swashplate.

8. The rotor/wing apparatus of claim 7, further comprising:

a frame rigidly mounted to said rotor/wing aircraft;

a pivot shaft rotatably mounted to said frame, said pivot shaft having first and second shaft ends; and

wherein said locking link further comprises an arm member having an attachment end attached to said first shaft end, said arm member being pivotable about said pivot shaft to move said proximal end from said first position to said second position.

9. The rotor/wing apparatus of claim 8, further comprising:

an actuator attached to said pivot shaft for causing said locking link to move from said second position to said first position.

10. The rotor/wing apparatus of claim 8, further comprising:

a bell crank arm attached to said second shaft end, said bell crank arm having a pivoting end and a free end; and

a linear actuator attached to said free end, said linear actuator adapted to rotate said pivot shaft for causing said locking link to move from said second position to said first position.

11. The rotor/wing apparatus of claim 7, further comprising:

a second rotor blade attached to and extending radially outward from said rotor hub, said second rotor blade being pivotable about a second pitch axis extending substantially radially outward from said azimuthal axis; and

a second pitch link having a second upper end and a second lower end, said second upper end being attached to said second rotor blade eccentric of said second pitch axis said second pitch link being operatively attached to said rotatable swashplate.

12. The rotor/wing apparatus of claim 11 further comprising:

a second separate locking link moveable from an engaged position in which said second locking link engages said second lower end to constrain said second pitch link against movement to a disengaged position in which said link disengages from said second lower end to permit said second pitch link to move in response to said rotatable swashplate.