US3942910A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Grip-yoke assembly with a redundant centrifugal load support
Assignee: Bell Helicopter Textron Inc
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Filing: 1974-05-13
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Granted: 1976-03-09
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Expires: 1994-05-13
Abstract
Abstract A grip-yoke assembly for attaching a helicopter blade to the mast of the helicopter rotor having a conventional primary coupling to carry the centrifugal loads and a redundant path operative should the primary coupling fail to insure continued operability of the blade. In one embodiment, the redundant load path has a bearing surface formed on the inboard end of the grip and a corresponding thrust bearing mounted on an inboard yoke fitting for engagement with the bearing surface upon failure of the coupling. In an alternative embodiment, a bearing surface is formed on an outboard grip fitting and a corresponding thrust bearing is supported on the yoke outboard of the grip fitting.
Inventors
- 👤 David E. Snyder
- 👤 Cecil E. Covington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:20
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/35; B64C27/46; B64C27/473; B64C27/48
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
109 words
A redundant coupling for attaching a helicopter rotor blade to a mast mounted yoke where a grip encompasses said yoke and is rotatably attached thereto by a primary coupling to allow blade pitch change while opposing centrifugal forces from said blade, comprising: a transverse member mounted on said grip; a restraint member on said yoke; and a thrust bearing normally free from stress supported between said restraint member and said transverse member and adapted to carry said centrifugal forces upon failure of said primary coupling to permit outward displacement of said grip to stress said thrust bearing thereby restraining said blade while maintaining pitch change capability of said blade.
Claim 2
Dependent Claim
109 words
A redundant coupling for attaching a helicopter rotor blade to a mast mounted yoke where a grip encompasses said yoke and is rotatably attached thereto by a primary coupling to allow blade pitch change while opposing centrifugal forces from said blade, comprising: a transverse member mounted on said grip; a restraint member on said yoke; and a thrust bearing normally free from stress supported between said restraint member and said transverse member and adapted to carry said centrifugal forces upon failure of said primary coupling to permit outward displacement of said grip to stress said thrust bearing thereby restraining said blade while maintaining pitch change capability of said blade.
Claim 3
Dependent Claim
20 words
The coupling of claim 1 additionally comprising elastomeric bearings attached between said grip and yoke for maintaining radial alignment therebetween.
Claim 4
Dependent Claim
18 words
The coupling of claim 1 wherein said transverse member is mounted on said grip at an inboard location.
Claim 5
Dependent Claim
18 words
The coupling of claim 3 wherein said transverse member comprises a load carrying dust cap on said grip.
Claim 6
Dependent Claim
18 words
The coupling of claim 3 wherein said restraint member comprises an inboard fitting on said yoke. and yoke,
Claim 7
Dependent Claim
18 words
The coupling of claim 1 wherein said transverse member is mounted on said grip at an outboard location.
Claim 8
Dependent Claim
16 words
The coupling of claim 6 wherein said transverse member comprises an outboard fitting on said grip.
Claim 9
Dependent Claim
18 words
The coupling of claim 6 wherein said restraint member is a radial bearing support member on said yoke.
Claim 10
Dependent Claim
13 words
The coupling of claim 1 wherein said primary coupling is a tension strap.
Claim 11
Dependent Claim
14 words
The coupling of claim 1 wherein said primary coupling is an elastomeric thrust pad.
Claim 12
Dependent Claim
82 words
In combination, means for connecting a main helicopter blade to the rotor having a yoke connected to the rotor, a grip enclosing the yoke and connected to the blade, a strap assembly connecting the grip and yoke. the improvement which comprises a transverse member on said grip, a portion of said yoke outboard of said transverse member normally free of centrifugal forces on said grip for contacting said transverse member and retaining said yoke in said grip upon failure of said strap.
Claim 13
Dependent Claim
82 words
In combination, means for connecting a main helicopter blade to the rotor having a yoke connected to the rotor, a grip enclosing the yoke and connected to the blade, a strap assembly connecting the grip and yoke. the improvement which comprises a transverse member on said grip, a portion of said yoke outboard of said transverse member normally free of centrifugal forces on said grip for contacting said transverse member and retaining said yoke in said grip upon failure of said strap.
Claim 14
Dependent Claim
17 words
The combination of claim 11 additionally comprising a thrust bearing mounted on said portion of said yoke.
Claim 15
Dependent Claim
116 words
A coupling for attaching a helicopter rotor blade to a mast comprising: a yoke attached to and extending from said mast; a grip enclosing said yoke and attached to said blade; bearing means interconnecting said grip and yoke to maintain relative axial alignment and permit limited radial rotation therebetween; a primary load supporting means connecting said yoke and grip for transferring centrifugal loads from said grip to said yoke and for allowing limited radial rotation therebetween; and redundant load supporting means on said grip and yoke normally free from said loads for transferring said loads from said grip to said yoke upon outward displacement of said grip due to failure of said primary load supporting means.
Claim 16
Dependent Claim
116 words
A coupling for attaching a helicopter rotor blade to a mast comprising: a yoke attached to and extending from said mast; a grip enclosing said yoke and attached to said blade; bearing means interconnecting said grip and yoke to maintain relative axial alignment and permit limited radial rotation therebetween; a primary load supporting means connecting said yoke and grip for transferring centrifugal loads from said grip to said yoke and for allowing limited radial rotation therebetween; and redundant load supporting means on said grip and yoke normally free from said loads for transferring said loads from said grip to said yoke upon outward displacement of said grip due to failure of said primary load supporting means.
Claim 17
Dependent Claim
15 words
The coupling of claim 13 wherein said primary load supporting means is a tension strap.
Claim 18
Dependent Claim
16 words
The coupling of claim 13 wherein said primary load supporting means is an elastomeric thrust pad.
Claim 19
Dependent Claim
44 words
The coupling of claim 13 wherein said secondary load supporting means comprises a thrust bearing mounted on said yoke, and a transverse member on said grip positioned inboard of said bearing for contact with said bearing upon failure of said primary load supporting means.
Claim 20
Dependent Claim
18 words
The coupling of claim 13 wherein said bearing means comprises elastomeric bearings attached between said yoke and grip.
Claim 21
Dependent Claim
128 words
In a coupling for attaching a helicopter rotor blade to a mast comprising in combination: a yoke attached to and extending from said mast; a grip enclosing said yoke and attached to said blade; bearing means interconnnecting said grip and yoke to maintain relative axial alignment and permit limited radial rotation; a primary load supporting means connecting said yoke and grip for transferring centrifugal loads from said grip to said yoke and for allowing limited radial rotation therebetween; and the improvement which comprises a redundant load supporting means on said grip and yoke normally free of said loads and positioned to transfer centrifugal loads from said grip to said yoke upon failure of said primary load supporting means and radial displacement of said blade relative to said yoke.
Claim 22
Dependent Claim
128 words
In a coupling for attaching a helicopter rotor blade to a mast comprising in combination: a yoke attached to and extending from said mast; a grip enclosing said yoke and attached to said blade; bearing means interconnnecting said grip and yoke to maintain relative axial alignment and permit limited radial rotation; a primary load supporting means connecting said yoke and grip for transferring centrifugal loads from said grip to said yoke and for allowing limited radial rotation therebetween; and the improvement which comprises a redundant load supporting means on said grip and yoke normally free of said loads and positioned to transfer centrifugal loads from said grip to said yoke upon failure of said primary load supporting means and radial displacement of said blade relative to said yoke.
Claim 23
Dependent Claim
15 words
The coupling of claim 18 wherein said primary load supporting means is a tension strap.
Claim 24
Dependent Claim
16 words
The coupling of claim 18 wherein said primary load supporting means is an elastomeric thrust pad.
Claim 25
Dependent Claim
44 words
The coupling of claim 18 wherein said secondary load supporting means comprises a thrust bearing mounted on said yoke, and a transverse member on said grip positioned inboard of said bearing for contact with said bearing upon failure of said primary load supporting means.
Claim 26
Dependent Claim
18 words
The coupling of claim 18 wherein said bearing means comprises elastomeric bearings attached between said yoke and grip.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-09 | 1979-09-08 | 1980-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-09 | 1983-09-08 | 1984-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-09 | 1987-09-08 | 1988-03-09 | $7700.00 | Window Closed / Lapsed |