US4047840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impact absorbing blade mounts for variable pitch blades
Assignee: National Aeronautics and Space Administration
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Filing: 1975-05-29
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Granted: 1977-09-13
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Expires: 1995-05-29
Abstract
Abstract A variable pitch blade and blade mount which is suitable for propellers, fans and the like and which has improved impact resistance. The invention is particularly directed to composite fan blades and blade mounting arrangements wherein the blades are permitted to pivot relative to a turbine hub about an axis generally parallel to the centerline of the engine upon impact of a large foreign object, such as a bird. By thus providing for the pivoting of the blades upon impact, centrifugal force recovery becomes the principal energy absorbing mechanism and a blade having improved impact strength is obtained.
Inventors
- 👤 Richard Ravenhall
- 👤 Charles T. Salemme
- 👤 Arthur P. Adamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:58
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/26; F04D29/32; F04D29/321; F04D29/322; F04D29/323; F01; F01D; F01D5/00; F01D5/30; F01D5/3007; F01D5/3053; F01D7/00; F02; F02K; F02K3/00; F02K3/02; F02K3/04; F02K3/06; F05; F05D; F05D2260/00; F05D2260/30; F05D2260/36; F05D2260/40; F05D2260/403; F05D2260/4031; F05D2260/70; F05D2260/74; F05D2260/79; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
83 words
A blade mount for a variable pitch blade including a blade root, said blade mount comprising: a. a jaw having opposing sides defining a cross-sectional shape corresponding to that of the blade root, said jaw being open on at least one end for slideably receiving said blade root, and providing for the pivoting of the blade about an axis for absorbing impact energy, and b. a tie bar interconnecting said jaw opposing sides to resist the expansion of said jaw during centrifugal loading.
Claim 2
Dependent Claim
83 words
A blade mount for a variable pitch blade including a blade root, said blade mount comprising: a. a jaw having opposing sides defining a cross-sectional shape corresponding to that of the blade root, said jaw being open on at least one end for slideably receiving said blade root, and providing for the pivoting of the blade about an axis for absorbing impact energy, and b. a tie bar interconnecting said jaw opposing sides to resist the expansion of said jaw during centrifugal loading.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1 wherein the opposing sides of said jaw include a plurality of fins extending outwardly to further resist the expansion of said jaw during centrifugal loading thereof.
Claim 4
Dependent Claim
23 words
The apparatus of claim 1 wherein said tie bar extends across said jaw open end to retain said blade root in said jaw.
Claim 5
Dependent Claim
33 words
The apparatus of claim 1 wherein said blade root and said jaw are generally of a keyhole shape and further wherein said blade root is pivotable within said jaw to absorb impact energy.
Claim 6
Dependent Claim
32 words
The apparatus of claim 1 wherein said jaw includes an outsert for receiving and rigidly retaining said blade root and an axially extending hole for pivotably mounting said outsert to a pin.
Claim 7
Dependent Claim
19 words
The apparatus of claim 5 wherein the opposing sides of said jaw define a shape of dovetail cross section.
Claim 8
Dependent Claim
58 words
The apparatus of claim 5 wherein: a. said outsert has at least one slot substantially orthagonal to said axially extending hole and b. said tie bar is disposable within said slot, said tie bar having shoulders on the ends thereof for engaging the respective opposing sides of said jaw, to resist expansion of said jaw during centrifugal loading.
Claim 9
Dependent Claim
40 words
The apparatus of claim 7 wherein: a. said blade root has at least one slot orthagonal to said axially extending hole and aligned with said blade root slot and b. said tie bar is disposed in said blade root slot.
Claim 10
Dependent Claim
18 words
The apparatus of claim 8 wherein said outsert and said tie bars are bonded to said blade root.
Claim 11
Dependent Claim
23 words
The apparatus of claim 9 whrein said tie bars are further provided with holes aligned with the axially extending hole in said outsert.
Claim 12
Dependent Claim
20 words
The apparatus of claim 10 and including a spindle with a clevis having a hole therein for receiving said pin.
Claim 13
Dependent Claim
84 words
An improved blade retaining apparatus for connecting a variable pitch blade to a rotatable hub, wherein the improvement comprises: a. a shank attached to said hub and extending substantially radially outwardly therefrom; b. means for rotating said shank on its longitudinal axis; and c. a jaw connected at its one end to the end of said shank and comprising a pair of oppositely disposed arms defining an enlarged slot for receiving a blade root and retaining it from movement in the radially outward direction.
Claim 14
Dependent Claim
84 words
An improved blade retaining apparatus for connecting a variable pitch blade to a rotatable hub, wherein the improvement comprises: a. a shank attached to said hub and extending substantially radially outwardly therefrom; b. means for rotating said shank on its longitudinal axis; and c. a jaw connected at its one end to the end of said shank and comprising a pair of oppositely disposed arms defining an enlarged slot for receiving a blade root and retaining it from movement in the radially outward direction.
Claim 15
Dependent Claim
28 words
The improved blade retaining apparatus of claim 12 and including at least one tie bar interconnecting said arms to resist expansion of said jaw during centrifugal loading thereof.
Claim 16
Dependent Claim
19 words
The improved blade retaining apparatus of claim 12 wherein said enlarged slot is substantially formed in a keyhole shape.
Claim 17
Dependent Claim
23 words
The improved blade retaining apparatus of claim 13 wherein said at least one tie bar extends across one end of the blade root.
Claim 18
Dependent Claim
18 words
The improved blade retaining apparatus of claim 12 wherein said slot is substantially formed in a dovetail shape.
Claim 19
Dependent Claim
30 words
The improved blade retaining apparatus of claim 12 wherein said jaw includes a base portion adapted to be connected to said shank so as to be pivotable about an axis.
Claim 20
Dependent Claim
29 words
The improved blade retaining apparatus of claim 17 wherein said base portion has a hole formed therein for receiving a pin which pivotally connects said base to said shank.
Claim 21
Dependent Claim
32 words
The improved blade retaining apparatus of claim 13 wherein said blade root has at least one transverse slot formed therein and further wherein said tie bar is disposed in said transverse slot.
Claim 22
Dependent Claim
34 words
The improved blade retaining apparatus of claim 19 wherein said jaw has formed therein at least one transverse slot for alignment with said blade root transverse slot and for receiving said tie bar therein.
Claim 23
Dependent Claim
25 words
The improved blade retaining apparatus of claim 13 wherein said tie bar includes at each end a shoulder for engagement with its associated jaw arm.
References Cited (Backward Citations)
CA483633A
Cited
US2936155A
Cited
GB740757A
Cited
US2997274A
Cited
DE1283852B
Cited
US3487879A
Cited
US3689177A
Cited
US3860361A
Cited
US3870434A
Cited
US3900274A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-12 | 1981-03-14 | 1981-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-12 | 1985-03-14 | 1985-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-12 | 1989-03-14 | 1989-09-13 | $7700.00 | Window Closed / Lapsed |