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Patent US3874815A successfully refreshed from Google Patents.
US3874815A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary head assembly for rotary wing aircraft
Assignee: Boeing Co
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Filing: 1973-11-15
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Granted: 1975-04-01
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Expires: 1993-11-15
Abstract
Abstract A rotor head assembly for rotary wing aircraft in which opposing blades are interconnected by an integral, flexible strap mounted on a hub by spaced clamping members extending transverse to the longitudinal axes of the blades. The clamping members preferably have a degree of torsional flexibility so as to absorb bending moments, permitting the strap and clamping members to twist about their transverse axes in response to flapping movements of the blades. This eliminates the need for bearings or ''''shoes'''' on the hub for supporting the blades. At the same time, by virtue of the spaced clamping members, a degree of bending in the flexible strap will occur between the points at which the blade is clamped to optimize the flapwise bending momemt distribution along the strap.
Inventors
- 👤 Joseph M Baskin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:48
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/33
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
88 words
A rotor head assembly for rotary wing aircraft comprising a rotor hub, a pair of blades disposed on opposite sides of said hub, integral flexible strap means interconnecting said blades, and strap mounting means connecting said strap means to said hub intermediate said blades, said mounting means comprising a pair of elongated devices extending transverse to the longitudinal axes of said blades at spaced points along said strap means for securing said strap means to the hub while permitting flexing of the strap means intermediate the elongated devices.
Claim 2
Dependent Claim
88 words
A rotor head assembly for rotary wing aircraft comprising a rotor hub, a pair of blades disposed on opposite sides of said hub, integral flexible strap means interconnecting said blades, and strap mounting means connecting said strap means to said hub intermediate said blades, said mounting means comprising a pair of elongated devices extending transverse to the longitudinal axes of said blades at spaced points along said strap means for securing said strap means to the hub while permitting flexing of the strap means intermediate the elongated devices.
Claim 3
Dependent Claim
38 words
The assembly of claim 1 wherein said elongated devices comprise clamping pads on opposite sides of said strap means, and means for drawing said clamping pads together to clamp the strap means to the hub at spaced points.
Claim 4
Dependent Claim
69 words
The assembly of claim 2 wherein two of said clamping pads are carried at spaced points on one hub plate while the remaining two clamping pads are carried on a second hub plate, the clamping pads being formed by flanges at the ends of the hub plates with the area intermediate the flanges being of reduced cross-sectional area to permit flexing of the strap means between the clamping pads.
Claim 5
Dependent Claim
43 words
The assembly of claim 1 wherein each of said elongated devices has a degree of torsional flexibility about an axis transverse to said longitudinal axes of the blades which permits each device and the strap mounted thereon to twist about said transverse axis.
Claim 6
Dependent Claim
20 words
The assembly of claim 4 wherein each of said elongated devices is formed from fiberglass fibers embedded in an epoxy.
Claim 7
Dependent Claim
48 words
The assembly of claim 4 wherein each of said elongated devices is formed from strip members forming an X-shaped cross-sectional configuration, and an epoxy material filling the cavities formed by the X-shaped configuration at their ends and in the area of their connection to said flexible strap means.
Claim 8
Dependent Claim
170 words
A rotor head assembly for rotary wing aircraft comprising a rotor hub, at least one pair of blades disposed on opposite sides of said hub, integral flexible strap means interconnecting said blades, and strap mounting means connecting said strap means to said hub intermediate said blades, said mounting means comprising a pair of elongated devices formed from strip members forming an X-shaped cross-sectional configuration, and an epoxy material filling the cavities formed by the X-shaped configuration at their ends and in the area of their connection to said flexible strap means, wherein said elongated devices extend transverse to the longitudinal axis of said blades at spaced points along said strap means for securing said strap means to one hub while permitting flexing of thE strap means intermediate to the elongated devices, and wherein each of said elongated devices has a degree of torsional flexibility about an axis transverse to said longitudinal axis of said blade which permits each device and the strap mounted thereon to twist about said transverse axis.
Claim 9
Dependent Claim
170 words
A rotor head assembly for rotary wing aircraft comprising a rotor hub, at least one pair of blades disposed on opposite sides of said hub, integral flexible strap means interconnecting said blades, and strap mounting means connecting said strap means to said hub intermediate said blades, said mounting means comprising a pair of elongated devices formed from strip members forming an X-shaped cross-sectional configuration, and an epoxy material filling the cavities formed by the X-shaped configuration at their ends and in the area of their connection to said flexible strap means, wherein said elongated devices extend transverse to the longitudinal axis of said blades at spaced points along said strap means for securing said strap means to one hub while permitting flexing of thE strap means intermediate to the elongated devices, and wherein each of said elongated devices has a degree of torsional flexibility about an axis transverse to said longitudinal axis of said blade which permits each device and the strap mounted thereon to twist about said transverse axis.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |