US3918839A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wind turbine
Assignee: United States Department of Energy
•
Filing: 1974-09-20
•
Granted: 1975-11-11
•
Expires: 1994-09-20
Abstract
Abstract A wind turbine rotatable about a shaft may include a drive rotor with one or more elongated blades each having a central outwardly curved portion of airfoil shape which produces rotary motion when the blade rotates in wind at a blade tip velocity to wind velocity ratio greater than about three or four, additional wind rotor means disposed at both ends of the curved portions of the elongated blade for rotatably accelerating the drive rotor to the desired velocity ratio, and means coupled to said rotors for utilizing the rotation thereof.
Inventors
- 👤 Bennie F Blackwell
- 👤 Louis V Feltz
- 👤 Randall C Maydew
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:47
CPC Classifications
F; F03; F03D; F03D3/00; F03D3/06; F03D3/062; F03D3/061; F05; F05B; F05B2240/00; F05B2240/20; F05B2240/21; F05B2240/211; F05B2240/212; F05B2240/213; Y; Y02; Y02E; Y02E10/00; Y02E10/70; Y02E10/74
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
115 words
A wind turbine comprising a rotatable shaft; a drive rotor having an elongated blade with a central curved portion of airfoil shape transverse to said curvature, and means for supporting said blade On said shaft with said airfoil shape directed along the path of movement of said blade for exerting significant driving force on said shaft when said curved blade portion attains a linear velocity to wind velocity ratio greater than about three; starter rotor means disposed on said shaft having vanes out of registry with the curved portion of said drive rotor for rotatably accelerating said shaft to said velocity ratio; and means coupled to said shaft for utilizing the rotation of said shaft.
Claim 2
Dependent Claim
115 words
A wind turbine comprising a rotatable shaft; a drive rotor having an elongated blade with a central curved portion of airfoil shape transverse to said curvature, and means for supporting said blade On said shaft with said airfoil shape directed along the path of movement of said blade for exerting significant driving force on said shaft when said curved blade portion attains a linear velocity to wind velocity ratio greater than about three; starter rotor means disposed on said shaft having vanes out of registry with the curved portion of said drive rotor for rotatably accelerating said shaft to said velocity ratio; and means coupled to said shaft for utilizing the rotation of said shaft.
Claim 3
Dependent Claim
25 words
The turbine of claim 1 wherein said drive rotor includes a plurality of said blades, each having a central outwardly curved portion of airfoil shape.
Claim 4
Dependent Claim
23 words
The turbine of claim 2 wherein said outwardly curved portions of said blades are arcuately shaped approximating a portion of a troposkien shape.
Claim 5
Dependent Claim
26 words
The turbine of claim 1 wherein said blade supporting means includes substantially straight blade segments connecting and supporting between them said curved portion of airfoil shape.
Claim 6
Dependent Claim
22 words
The turbine of claim 4 including means for separating the ends of said curved portion of said blade from said blade segments.
Claim 7
Dependent Claim
19 words
The turbine of claim 4 including tip plate spoilers at each end of said curved portion of said blade.
Claim 8
Dependent Claim
17 words
The turbine of claim 6 wherein said tip plate spoilers are positioned generally perpendicular to said shaft.
Claim 9
Dependent Claim
19 words
The turbine of claim 4 including weight members positioned at each end of said curved portion of said blade.
Claim 10
Dependent Claim
44 words
The turbine of claim 4 wherein said curved portion of said blade includes a high strength, elongated strap disposed at the center of said curved portion, a foam core disposed about said strap in said airfoil shape, and an outer substantially impervious skin thereover.
Claim 11
Dependent Claim
51 words
The turbine of claim 9 wherein said strap is bent into an arcuate shape, said foam comprises inner and outer airfoil shape segments adhered to each other and to said strap on both sides of said strap, and the outer surface of said foam segments is coated with said impervious skin.
Claim 12
Dependent Claim
15 words
The turbine of claim 1 wherein said velocity ratio is from about 5 to 7.
Claim 13
Dependent Claim
97 words
The turbine of claim 1 wherein said shaft is generally vertical and said starter rotor means include a first self-starting rotor disposed above said curved portion and a second self-starting rotor disposed below said curved portion; each of said self-starting rotors including a plurality of hollow-shaped vanes facing in opposite directions with respect to each other, and means for supporting said vanes on said shaft partially overlapping each other in a generally S-shaped fashion for directing wind caught by the hollow portion of one vane into the hollow portion of at least another vane in each rotor.
Claim 14
Dependent Claim
23 words
The turbine of claim 12 wherein the outer radii of said self-starting rotors are less than the outer radius of said drive rotor.
Claim 15
Dependent Claim
32 words
The turbine of claim 13 wherein the ratio of said radii is from about 5 to 6 to 1 and aid in rotation of said turbine at and above said velocity ratio.
Claim 16
Dependent Claim
19 words
The turbine of claim 12 wherein said vanes of said self-starting rotors are interdigitated with respect to each other.
Claim 17
Dependent Claim
34 words
The turbine of claim 1 including a plurality of said drive rotors supported one above the other on said shaft, each succeding drive rotor having a diameter greater than the next adjacent lower rotor.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |