Equipment for folding the blades of a main helicopter rotor

• US 4,268,222 A
• Filed: 04/12/1979
• Issued: 05/19/1981
• Est. Priority Date: 04/17/1978
• Status: Expired due to Term

• Current Assignee: Aerospatiale Societe Nationale Industrielle
• Original Assignee: Aerospatiale Societe Nationale Industrielle
• Inventors: Bernard, Louis A.
• Primary Examiner(s): Jillions, John M.
• Application Number:
  US06/029,510
• Time in Patent Office: 768 Days
• Field of Search: 416/143, 416/142, 416/134 A, 416/1
• US Class Current: 416/1
• CPC Class Codes: B64C 27/50 Blades foldable to facilitate stowage of aircraft

Abstract

The invention relates to equipment which makes it possible to fold the blades of a rotor, in particular of the type comprising a star-shaped hub with arms flexible in the direction perpendicular to the plane of the star-shaped hub.

This equipment comprises a housing which is detachably mounted on the rigid central part of the rotor hub. This housing carries elongate supports at the side. The free end of each support is detachably joined to the upper part of the folding shaft of the corresponding blade. This folding shaft can consist of a spindle replacing a link shaft between the foot of the blade and the corresponding arm of the hub.

Claims

1. Equipment for folding the blades of a main helicopter rotor, in particular of the type having a star-shaped hub with a rigid central part and provided with arms which are flattened in the plane of the star and flexible perpendicularly to this plane, a blade root being joined to the end of each arm of said hub by means of members having at least one link shaft which is substantially perpendicular to the plane of the star, said equipment essentially comprising

a housing adapted to be fitted over said rigid central part of said hub,

and rigid elongate supports linked by one end to said housing,

and a folding shaft linking the other end of each of said elongate supports to one of said blade roots with the number of supports at most equal in number to the number of blades of the helicopter rotor.

2. Equipment according to claim 1 in which one said link shaft at each said arm of said hub is said folding shaft connecting one of said supports to one of said blade roots.

3. Equipment according to claim 1 in which said folding shaft is a spindle substituted for one of said link shafts connecting one of said supports to one of said blade roots.

4. Equipment according to claim 1 in which said housing is cylinder shaped.

5. Equipment according to claim 1 in which said housing is prism shaped.

6. Equipment according to claim 1 in which articulations are provided on the sidewalls of said housing connecting said elongate supports to said housing with the axes of said articulations being substantially perpendicular to the axis of the rotor.

7. Equipment according to claim 1, which further comprises fastening means for detachably fixing the lower part of each said folding shaft into a socket integral with the root of the corresponding blade.

8. Equipment according to claim 7, in which said fastening means comprises elastic clamps.

9. Equipment according to claim 7, in which said fastening means comprises pins.

10. Equipment according to claim 1, which further comprises fastening means for detachably fixing the upper part of each said folding shaft into a socket integral with the end of said corresponding elongate support.

11. Equipment according to claim 10, in which said fastening means comprise elastic clamps.

12. Equipment according to claim 10, in which said fastening means comprise pins.

13. Process for manually folding the blades of a main helicopter rotor having a hub with a rigid central part comprising the steps of fitting a housing, provided with elongate supports, over the rigid central part of the rotor hub, and then, for each blade which has not stopped above the longitudinal axis of the helicopter, supporting the blade by means of a pole, substituting a folding shaft for one of the link shafts of the blade, fixing the upper part of the said folding shaft to the end of the corresponding elongate support, removing any further link shaft from the blade, causing the blade to pivot about the folding shaft towards the rear of the helicopter, using the said pole, and then, immobilising the blade, relative to the fuselage, using fastening means, in a position in which the folded blade is substantially parallel to the said longitudinal axis.

14. Process for manually folding the blades of a main helicopter rotor having a hub with a rigid central part comprising the steps of fitting a housing, provided with elongate supports, over the rigid central part of the rotor hub, and then, for each blade which has not stopped above the longitudinal axis of the helicopter, fixing the upper part of a link shaft acting as a folding shaft to the end of the corresponding elongate support, removing any further link shaft from the blade, causing the blade to pivot about the folding shaft towards the rear of the helicopter, using a pole, and then immobilizing the blade, relative to the fuselage, using fastening means, in a position in which the folded blade is substantially parallel to the said longitudinal axis.

15. The process of claim 14 wherein said fastening means is said pole.