US3790302A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tail rotor mounting for coning relief
Assignee: Bell Helicopter Textron Inc
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Filing: 1972-10-10
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Granted: 1974-02-05
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Expires: 1992-10-10
Abstract
Abstract Helicopter tail rotors provide anti-torque forces to maintain stabilized flight and further provide aircraft heading control. Aerodynamic forces generated on the rotor blade cause the tip thereof to move out of line with the pitch change axis of the blade, an effect known as ''''coning,'''' which produces undesirable forces on the rotor blade, the hub and the tail rotor control system. Each tail rotor blade is attached to a blade grip which is coupled to a yoke through laminated elastomeric bearings that provide in-plane stiffness while permitting blade coning in such a manner as to relieve the undesired coning effect forces.
Inventors
- 👤 R Pascher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:12
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/37; B64C27/41; B64C27/43; B64C27/35
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
100 words
A helicopter tail rotor blade mounting with coning relief which comprises: a rotor yoke pivotally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, means for flexibly mounting the inboard end of the blade grip to said yoke, and a translation bearing coupling the outboard end of the rotor yoke to said grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting movement relative to said yoke in the plane of rotation thereof.
Claim 2
Dependent Claim
100 words
A helicopter tail rotor blade mounting with coning relief which comprises: a rotor yoke pivotally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, means for flexibly mounting the inboard end of the blade grip to said yoke, and a translation bearing coupling the outboard end of the rotor yoke to said grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting movement relative to said yoke in the plane of rotation thereof.
Claim 3
Dependent Claim
70 words
A helicopter rotor blade mounting as set forth in claim 1 wherein said translation bearing includes concentric, laminated, elastomeric elements mounted on the blade grip, and parallel elastomeric plates mounted to opposite sides of said elements and spaced apart in the plane of rotation to limit by compression resistance said movement in the plane of rotation and to permit by shear deflection said movement perpendicular to the plane of rotation.
Claim 4
Dependent Claim
36 words
A helicopter rotor blade mounting as set forth in claim 1 including a thrust bearing coupled to the blade grip at a point between the inboard and outboard ends thereof and fastened to the rotor yoke.
Claim 5
Dependent Claim
31 words
A helicopter rotor blade mounting as set forth in claim 3 wherein said thrust bearing includes spherical, laminated, elastomeric elements coupled to the blade grip and attached to the rotor yoke.
Claim 6
Dependent Claim
37 words
A helicopter rotor blade mounting as set forth in claim 1 including flapping bearing means supported on a trunnion attached to said mast and coupled to the rotor yoke for pivotally mounting said yoke to the mast.
Claim 7
Dependent Claim
41 words
A helicopter rotor blade mounting as set forth in claim 5 wherein said flapping bearing includes concentric, laminated, elastomeric elements having an inner member supported on said trunnion and an outer circumference surface mounted in an opening of the rotor yoke.
Claim 8
Dependent Claim
153 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke pivotally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, means for flexibly mounting the inboard end of the blade grip to said yoke, a translation bearing coupling the outboard end of the rotor yoke to said grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting freedom of movement relative to said guide in the plane of rotation thereof, a trust bearing coupled to the blade grip at a point between the inboard and outboard ends thereof and fastened to the rotor yoke, and flapping bearing means supported on a trunnion attached to said mast and coupled to the rotor yoke for pivotally mounting said yoke to the supporting mast.
Claim 9
Dependent Claim
153 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke pivotally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, means for flexibly mounting the inboard end of the blade grip to said yoke, a translation bearing coupling the outboard end of the rotor yoke to said grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting freedom of movement relative to said guide in the plane of rotation thereof, a trust bearing coupled to the blade grip at a point between the inboard and outboard ends thereof and fastened to the rotor yoke, and flapping bearing means supported on a trunnion attached to said mast and coupled to the rotor yoke for pivotally mounting said yoke to the supporting mast.
Claim 10
Dependent Claim
70 words
A helicopter rotor blade mounting as set forth in claim 7 wherein said translation bearing includes concentric, laminated, elastomeric elements mounted on the blade grip, and parallel elastomeric plates mounted on opposite sides of said elements and spacing apart in the plane of rotation to limit by compression resistance said movement in the plane of rotation and to permit by shear deflection said movement perpendicular to the plane of operation.
Claim 11
Dependent Claim
31 words
A helicopter rotor blade mounting as set forth in claim 8 wherein said thrust bearing includes spherical, laminated, elastomeric elements coupled to the blade grip and attached to the rotor yoke.
Claim 12
Dependent Claim
41 words
A helicopter rotor blade mounting as set forth in claim 9 wherein said flapping bearing includes concentric, laminated, elastomeric elements having an inner opening supported on said trunnion and an outer circumference surface mounted in an opening of the rotor yoke.
Claim 13
Dependent Claim
116 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke pivoTally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, a hinge bearing coupled to the inboard end of the blade grip and the inboard end of the rotor yoke for flexibly mounting the blade grip to said yoke, and means for coupling the outboard end of the rotor yoke and the blade grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting movement relative to said yoke in the plane of rotation thereof.
Claim 14
Dependent Claim
116 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke pivoTally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, a hinge bearing coupled to the inboard end of the blade grip and the inboard end of the rotor yoke for flexibly mounting the blade grip to said yoke, and means for coupling the outboard end of the rotor yoke and the blade grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting movement relative to said yoke in the plane of rotation thereof.
Claim 15
Dependent Claim
34 words
A helicopter rotor blade mounting as set forth in claim 11 wherein said hinge bearing includes spherical, laminated, elastomeric elements coupled to the blade grip and mounted into a fitting of the rotor yoke.
Claim 16
Dependent Claim
41 words
A helicopter rotor blade mounting as set forth in claim 12 including flapping bearing means of concentric, laminated, elastomeric elements having an inner member supported on a trunnion and an outer circumference surface mounted in a fitting of the rotor yoke.
Claim 17
Dependent Claim
140 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke pivotally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, a hinge bearing coupled to the inboard end of the blade grip and the inboard end of the rotor yoke for flexibly mounting the blade grip to said yoke, means for coupling the outboard end of the rotor yoke and the blade grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting movement relative to said yoke in the plane of rotation thereof, and a thrust bearing coupled to the blade grip at a point between the inboard and outboard ends thereof and fastened to the rotor yoke.
Claim 18
Dependent Claim
140 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke pivotally mounted to rotate with a supporting mast, a blade grip and a rotor blade attached thereto at the outboard end of said grip and including pitch control means, a hinge bearing coupled to the inboard end of the blade grip and the inboard end of the rotor yoke for flexibly mounting the blade grip to said yoke, means for coupling the outboard end of the rotor yoke and the blade grip for translation freedom of the blade in a direction perpendicular to the plane of rotation while restricting movement relative to said yoke in the plane of rotation thereof, and a thrust bearing coupled to the blade grip at a point between the inboard and outboard ends thereof and fastened to the rotor yoke.
Claim 19
Dependent Claim
31 words
A helicopter rotor blade mounting as set forth in claim 14 wherein said thrust bearing includes spherical, laminated, elastomeric elements coupled to the blade grip and attached to the rotor yoke.
Claim 20
Dependent Claim
34 words
A helicopter rotor blade mounting as set forth in claim 14 wherein said hinge bearing includes spherical, laminated, elastomeric elements coupled to the blade grip and mounting into a fitting of the rotor yoke.
Claim 21
Dependent Claim
37 words
A helicopter rotor blade mounting as set forth in claim 14 including flapping bearing means supported on a trunnion attached to said mast and coupled to the rotor yoke for pivotally mounting said yoke to the mast.
Claim 22
Dependent Claim
40 words
A helicopter rotor blade mounting as set forth in claim 17 wherein said flapping bearing includes concentric, laminated, elastomeric elements having an inner member supported on said trunnion and an outer circumference mounted in an opening of the rotor yoke.
Claim 23
Dependent Claim
197 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke, a flapping bearing having concentric, laminated, elastomeric elements with an inner surface supported on a trunnion attached to a supporting mast and an outer circumference surface mounted in an opening of said rotor yoke, a blade grip and rotor blade attached thereto at the outboard end of said grip and including pitch control means, a hinge bearing having spherical, laminated, elastomeric elements coupled to the inboard end of the blade grip and inboard end of the rotor yoke for flexibly mounting the blade grip to said yoke, a translation bearing for translation freedom of the blade in a direction perpendicular to the plane of rotation and having concentric, laminated, elastomeric elements mounted on the blade grip and including parallel elastomeric plates mounted to opposite sides of said elements and spaced apart in the plane of rotation to limit by compression resistance movement relative to said yoke in the plane of rotation thereof, and a thrust bearing having spherical, laminated, elastomeric elements coupled to the blade grip at a point between the inboard and outboard ends thereOf and fastened to the rotor yoke.
Claim 24
Dependent Claim
197 words
A helicopter tail rotor blade mounting with coning relief, comprising in combination: a rotor yoke, a flapping bearing having concentric, laminated, elastomeric elements with an inner surface supported on a trunnion attached to a supporting mast and an outer circumference surface mounted in an opening of said rotor yoke, a blade grip and rotor blade attached thereto at the outboard end of said grip and including pitch control means, a hinge bearing having spherical, laminated, elastomeric elements coupled to the inboard end of the blade grip and inboard end of the rotor yoke for flexibly mounting the blade grip to said yoke, a translation bearing for translation freedom of the blade in a direction perpendicular to the plane of rotation and having concentric, laminated, elastomeric elements mounted on the blade grip and including parallel elastomeric plates mounted to opposite sides of said elements and spaced apart in the plane of rotation to limit by compression resistance movement relative to said yoke in the plane of rotation thereof, and a thrust bearing having spherical, laminated, elastomeric elements coupled to the blade grip at a point between the inboard and outboard ends thereOf and fastened to the rotor yoke.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |