US 5,431,540 A · Main rotor pitch control rod subassembly

Abstract

One embodiment of a main rotor pitch control rod subassembly includes an upper rod end segment having a bearing subassembly, a lower rod end segment having a bearing subassembly, an eccentric bushing disposed in rotatable combination with the upper rod end segment bearing subassembly for varying the axial length of the pitch control rod subassembly, a composite central body structure interposed between the upper and lower end segments, a composite strap member wrapped around and secured in combination with the lower end segment bearing subassembly, the composite central body structure, and the upper end segment bearing subassembly, eccentric bushing combination, a composite overwrap overlayed in combination with the composite strap member, a locking key member and a clamp-up bolt for clamping the composite strap member in tensioned combination with the locking key member, and a locking bolt. The eccentric bushing has a plurality of spaced apart bushing apertures formed therethrough, and the locking key member includes a clevis configuration having a plurality of spaced key apertures formed therethrough, interaction between the bushing and key apertures providing a fine, vernier-type adjustment capability. To vary the axial length of the pitch control rod subassembly, the eccentric bushing is rotated about the upper rod end segment bearing subassembly to a predetermined position wherein one of the bushing apertures aligns with one pair of the key apertures. The locking bolt is inserted through the aligned apertures to lock the eccentric bushing in the predetermined position.

Claims23

Dependent claims

A pitch control rod subassembly for a helicopter rotor hub assembly that includes a rotating swashplate and a pitch arm, comprising:

upper and lower rod end segments;
first and second bearing subassembly means for accommodating displacements induced in said pitch control rod subassembly during operation of the helicopter rotor hub assembly, said first bearing subassembly means being operatively disposed in combination with said upper rod end segment and the pitch arm and said second bearing subassembly means being operatively disposed in combination with said lower rod end segment and the rotating swashplate;
central body structure means interposed between said first and second bearing subassembly means for reacting compressive loads exerted on said pitch control rod subassembly and for precluding buckling of said pitch control rod subassembly in compression;
strap member means for reacting tension loads exerted on said pitch control rod subassembly and for defining the configuration of said upper and lower rod end segments of said pitch control rod subassembly;
eccentric bushing means disposed in rotatable combination with one of said first and second bearing subassembly means for varying the axial length of said pitch control rod subassembly by rotation of said eccentric bushing means, said eccentric bushing means having a plurality of bushing apertures formed therethrough;
and
means for interacting with one of said bushing apertures of said eccentric bushing means to lock said eccentric bushing means in a predetermined position after rotation of said eccentric bushing means to vary the axial length of said pitch control rod subassembly.

4 more elements

A pitch control rod subassembly for a helicopter main rotor hub assembly that includes a rotating swashplate and a pitch arm, comprising:

an upper rod end segment including a bearing subassembly;
a lower rod end segment including a bearing subassembly;
a central body structure interposed between said bearing subassemblies of said upper and lower rod end segments;
an eccentric bushing having a plurality of spaced apart bushing apertures formed therethrough mounted in rotatable combination with one of said bearing subassemblies;
a strap member wrapped around and secured in combination with said eccentric bushing, bearing subassembly combination, said central body structure, and said other bearing subassembly;
an overwrap member overlayed in combination with said strap member;
and
locking key member means for clamping up said strap member wherein said strap member is place in tension, said locking key member means further including means for interacting with one of said plurality of bushing apertures to lack said eccentric bushing in a predetermined position after rotation of said eccentric bushing to vary the axial length of said pitch control rod subassembly.

5 more elements

A pitch control rod subassembly for a helicopter hub assembly that includes a rotating swashplate and a pitch arm, comprising:

an upper rod end segment including a bearing subassembly;
an eccentric bushing having a plurality of bushing apertures formed therethrough mounted in rotatable combination with said bearing subassembly of said upper rod end segment;
a lower rod end segment including a bearing subassembly;
a composite central body structure interposed between said bearing subassemblies of said upper and lower rod end segments;
a composite strap member wrapped around and secured in combination with said eccentric bushing, bearing subassembly combination, said composite central body structure, and said bearing subassembly of said lower rod end segment;
a composite overwrap overlayed in combination with said composite strap member;
a locking key member configured to interact with said composite strap member for tensioning thereof, said locking key member including opposed sidewalls having a plurality of key apertures formed therethrough, said opposed sidewalls having a clevis configuration superposed in combination with said eccentric bushing;
clamp-up means for clamping said composite strap member in tensioned combination with said locking key member;
and
a locking bolt;
said eccentric bushing being rotatably about said upper rod end segment bearing subassembly to a predetermined position to vary the axial length of said pitch control rod subassembly, rotation of said eccentric bushing to said predetermined position causing one of said bushing apertures to align with one pair of said key apertures;
said locking bolt being inserted through said bushing aperture and said one pair of said key apertures in alignment to lock said eccentric bushing in said predetermined position after rotation of said eccentric bushing to vary the axial length of said pitch control rod subassembly.

9 more elements

Dependencies are inferred from the claim text.

Main rotor pitch control rod subassembly

Life of this patent

Main rotor pitch control rod subassembly

Life of this patent

Abstract

Claims23