Patent US1444554A successfully refreshed from Google Patents.
Patent US3778189A successfully refreshed from Google Patents.
US3778189A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elastomeric helicopter rotor head with dynamic and static blade coning and droop stops
Assignee: RTX Corp
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Filing: 1972-09-05
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Granted: 1973-12-11
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Expires: 1992-09-05
Abstract
Abstract An elastomeric helicopter rotor having a blade mounted for universal motion about the intersection of the blade pitch change, flapping and lead-lag axes and including blade coning and droop stops, including a ring member rotatably mounted about the pitch change axis on the blade and coning and droop stops constituting segments of circular members whose centers lie on the blade lead-lag axes and with the ring member and coning stop and droop stop members presenting mating surfaces to one another so that as the blade moves in lead-lag motion while the blade ring member is in line or surface mating contact with either the coning stop surface or the static or dynamic droop stop surfaces, a relative rotation will be established therebetween for full support of the blade throughout the lead-lag motion, without affecting blade pitch angle or flapping angle, without preventing independent blade pitch change, and without scuffing of parts.
Inventors
- 👤 D Ferris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:45
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/35; B64C27/322
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
172 words
An articulated helicopter rotor including: A. a rotor hub adapted to be mounted for rotation, B. at least one helicopter blade projecting substantially radially from said hub and having a pitch change axis, a leadlag axis, and a flapping axis intersecting at a common point, C. means supporting said blade from said hub for universal motion about the intersection of said axes, D. a ring member mounted on said blade for rotation relative thereto about said pitch change axis and at a station radially outward of said point of intersection and having: 1. a selectively shaped surface positioned to move toward said hub as said droops downwardly, E. a droop stop member connected to said hub and having a selectively shaped surface positioned to intercepting said ring member when said blade droops downwardly to a first selected angle and which surface is shaped to present a corresponding mating surface with said ring member surface to effect relative rotation therebetween as said blade moves in lead-lag motion when said surfaces are in contact.
Claim 2
Dependent Claim
172 words
An articulated helicopter rotor including: A. a rotor hub adapted to be mounted for rotation, B. at least one helicopter blade projecting substantially radially from said hub and having a pitch change axis, a leadlag axis, and a flapping axis intersecting at a common point, C. means supporting said blade from said hub for universal motion about the intersection of said axes, D. a ring member mounted on said blade for rotation relative thereto about said pitch change axis and at a station radially outward of said point of intersection and having: 1. a selectively shaped surface positioned to move toward said hub as said droops downwardly, E. a droop stop member connected to said hub and having a selectively shaped surface positioned to intercepting said ring member when said blade droops downwardly to a first selected angle and which surface is shaped to present a corresponding mating surface with said ring member surface to effect relative rotation therebetween as said blade moves in lead-lag motion when said surfaces are in contact.
Claim 3
Dependent Claim
26 words
A rotor according to claim 1 wherein said droop stop member surface is conical with the apex thereof located at said point intersection of said axes.
Claim 4
Dependent Claim
24 words
A rotor according to claim 1 wherein the mating surfaces of said droop stop member and said ring member are concave-convex for mating engagement.
Claim 5
Dependent Claim
30 words
A rotor according to claim 1 wherein selectively shaped surfaces of said ring member and droop stop member are frustoconical with the apexes thereof positioned at said point of intersection.
Claim 6
Dependent Claim
163 words
A rotor according to claim 1 and including a centrifugally responsive member having a First selectively shaped surface corresponding to said selectively shaped surface of said ring member and a second selectively shaped surface corresponding to said selectively shaped surface of said droop stop member and being pivotally mounted with respect to said blade and hub for motion between a first position wherein said pivotally mounted member is positioned between the selectively shaped surfaces of said ring member and said droop stop member at low rotor speeds or when the rotor is stopped and oriented so as to present its first selectively shaped surface to said selectively shaped surface of said ring member for mating engagement therewith and to present its second selectively shaped surface to said selectively shaped surface of said droop stop member for mating engagement therewith when said blade droops downwardly beyond a second selected angle, and a second position remote from said ring member and said droop stop member.
Claim 7
Dependent Claim
46 words
A rotor according to claim 5 wherein said droop stop member is wedge shaped between said first and second selectively shaped surfaces so that said droop stop member is locked in position between said ring member and said droop stop member when in said first position.
Claim 8
Dependent Claim
95 words
A rotor according to claim 6 wherein said selectively shaped surfaces of said droop stop member, said ring member and said centrifugally responsive member are arcuate with said first selectively shaped surface of said centrifugally responsive member shaped to be in mating engagement with and corresponding to said selectively shaped surface of said ring member and with said second selectively shaped surface of said centrifugally responsive member shaped to be in mating engagement with and corresponding to said selectively surface of said droop stop member when said centrifugal responsive member is in said first position.
Claim 9
Dependent Claim
80 words
A rotor according to claim 5 wherein said selectively shaped surfaces of said ring member and said droop stop member and said selectively shaped surfaces of said centrifugally responsive member are shaped so that concave convex mating occurs between said first selectively shaped surface of said centrifugally responsive member and said ring member and between said second selectively shaped surface of said centrifugally responsive member and said droop stop member when said centrifugally responsive member is in said first position.
Claim 10
Dependent Claim
61 words
A rotor according to claim 8 wherein said centrifugally responsive member is of wedge-shaped cross section between said first and second selectively shaped surfaces thereof so that said centrifugally actuated member is locked in said first position when its first and second selectively shaped surfaces, respectively, matingly engage the selectively shaped surfaces of said ring member and said droop stop member.
Claim 11
Dependent Claim
18 words
A rotor according to claim 5 wherein said second selected angle is less than said first selected angle.
Claim 12
Dependent Claim
28 words
A rotor according to claim 1 wherein said support means includes a spherical elastomeric bearing centered about said point of intersection and having alternate elastomeric and rigid laminates.
Claim 13
Dependent Claim
32 words
A rotor according to claim 1 wherein said droop stop member is a circular segment which lies in a substantially horizontal plane and the center of which lies on the lead-lag axis.
Claim 14
Dependent Claim
74 words
A rotor according to claim 1 and including a coning limit stop member connected to said hub and having a selectively shaped surface positioned to intercept said ring member when said blade flaps or cones upwardly to a selected angle and which surface is shaped to present a corresponding mating surface with said ring member surface to effect relative rotation therebetween as said blade moves in lead-lag motion when said surfaces are in contact.
Claim 15
Dependent Claim
31 words
A rotor according to claim 13 wherein said coning limit member is a circular segment which lies in a substantially horizontal plane, the center of which lies on said lead-lag axis.
Claim 16
Dependent Claim
67 words
A rotor according to claim 1 wherein said selectively shaped surface of said ring Member and said selectively shaped surface of said droop stop member are frustoconical with apexes positioned at said point of intersection and concentric about said pitch change axis and said lead-lag axis, respectively, and which are shaped to form line contact when said selectively shaped surfaces abut and rotate relative to one another.
Claim 17
Dependent Claim
63 words
A rotor according to claim 1 wherein said selectively shaped surface of said ring member and said selectively shaped surface of said droop stop member are shaped to be spherical about either a point on the pitch change axis or a point on the lead-lag axis so as to be in line contact when said surfaces engage and rotate relative to one another.
Claim 18
Dependent Claim
123 words
A rotor according to claim 5 wherein said selectively shaped surfaces of said ring member, said droop stop member and said centrifugally responsive member are frustoconical with apexes located at said point of intersection of said pitch change, lead-lag and flapping axes and wherein said selectively shaped surfaces of said droop stop member and said centrifugally responsive member are concentric about said lead-lag axis and said selectively shaped surface of said ring member is concentric about said pitch change axis so that said blade may move in lead-lag motion and at constant droop angle and without altering blade pitch as said ring member and said droop stop member rotate relative to each other as said selectively shaped surfaces thereof are in continuous engagement.
Claim 19
Dependent Claim
80 words
A rotor according to claim 15 and including a coning limit stop member connected to said hub and having a selectively shaped surface which is frustoconical with its apex positioned at said point of intersection and concentric about lead-lag axis, and which is shaped to form line contact when said selectively shaped surfaces of said ring member and said coning angle limit member rotate relative to one another while in continuous contact and with said blade at constant flapping angle.
Claim 20
Dependent Claim
105 words
A rotor according to claim 16 and including a coning angle limit stop member connected to said hub and having a selectively shaped surface which is spherical about a point on the lead-lag axis or the pitch change axis and which corresponds in curvature with said selectively shaped surface of said ring member and is positioned to contact said selectively shaped surface of said ring member when said blade coning angle reaches a selected maximum so as to be in line contact when said selectively shaped surface of said ring member and said coning angle limit stop member engage and rotate relative to one another.
Claim 21
Dependent Claim
80 words
A rotor according to claim 5 wherein said selectively shaped surfaces of said ring member, said droop stop member, and said centrifugally responsive member are spherical about points located on said pitch change axis or said lead-lag axis and of common radius and wherein said selectively shaped surfaces of said droop stop member and said centrifugally responsive member are concentric about said lead-lag axis, and said selectively shaped surface of said ring member is concentric about said pitch change axis.
Claim 22
Dependent Claim
92 words
An articulated helicopter rotor including: A. a rotor hub adapted to be mounted for rotation, B. at least one helicopter blade projecting substantially radially from said hub and having a pitch change axis, a lead-lag axis and a flapping axis intersecting at a common point, C. means supporting said blade from said hub for universal motion about the intersection of said axes, D. a ring member mounted on said blade for rotation relative thereto about said pitch change axis and at a station radially outward of said point of intersection and having:
Claim 23
Dependent Claim
92 words
An articulated helicopter rotor including: A. a rotor hub adapted to be mounted for rotation, B. at least one helicopter blade projecting substantially radially from said hub and having a pitch change axis, a lead-lag axis and a flapping axis intersecting at a common point, C. means supporting said blade from said hub for universal motion about the intersection of said axes, D. a ring member mounted on said blade for rotation relative thereto about said pitch change axis and at a station radially outward of said point of intersection and having:
Claim 24
Dependent Claim
33 words
A rotor according to claim 21 wherein said selectively shaped surfaces of said ring member and said droop stop member are segmented spheres concentric about said pitch change axis or said lead-lag axis.
References Cited (Backward Citations)
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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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |