US4230291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tuned spring-mass vibration absorber
Assignee: RTX Corp
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Filing: 1978-06-07
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Granted: 1980-10-28
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Expires: 1998-06-07
Abstract
Abstract A tuned spring-mass vibration absorber in which a dynamic mass is suspended from a vibrating support member, such as a helicopter fuselage, by a plurality of cantilevered leaf springs integrally connected to the dynamic mass at selected stations so that the mass CG and the spring center of force are coincident, so that the springs are shaped to constitute a substantial part of the vibration absorber effective mass, and so that the springs are pivotally connected to the support member so as to impart no moments thereto.
Inventors
- 👤 John Marshall II, deceased
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:05
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/001; F; F16; F16F; F16F7/00; F16F7/10; F16F7/104; F16F7/116; B64C2027/005
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
211 words
A tuned spring-mass vibration absorber adapted for use in a helicopter fuselage comprising: (A) a dynamic mass member of selected mass and shaped to define at least one flat surface and a selectively positioned mass center of gravity, (B) means suspending said dynamic mass member from the fuselage comprising: (1) three leaf spring members comprising a center spring member with side spring members on opposite sides thereof and each spring member being of constant thickness and having a wide end and tapering gradually therefrom to a narrow end and extending in parallel relationship to one another and with the width of the center spring member being twice that of the side spring members and with the center spring member being oriented in the opposite direction to the side spring members, (2) first means pivotally connecting the narrow ends of said leaf spring members to the fuselage so that no moment reactions are imparted to the fuselage from the spring members, and (3) second means rigidly connecting the wide ends of said spring members to said mass member flat surface and at stations in spaced relation to the mass member center of gravity so that said mass member is suspended from said spring members for vertical motion with respect to the fuselage.
Claim 2
Dependent Claim
211 words
A tuned spring-mass vibration absorber adapted for use in a helicopter fuselage comprising: (A) a dynamic mass member of selected mass and shaped to define at least one flat surface and a selectively positioned mass center of gravity, (B) means suspending said dynamic mass member from the fuselage comprising: (1) three leaf spring members comprising a center spring member with side spring members on opposite sides thereof and each spring member being of constant thickness and having a wide end and tapering gradually therefrom to a narrow end and extending in parallel relationship to one another and with the width of the center spring member being twice that of the side spring members and with the center spring member being oriented in the opposite direction to the side spring members, (2) first means pivotally connecting the narrow ends of said leaf spring members to the fuselage so that no moment reactions are imparted to the fuselage from the spring members, and (3) second means rigidly connecting the wide ends of said spring members to said mass member flat surface and at stations in spaced relation to the mass member center of gravity so that said mass member is suspended from said spring members for vertical motion with respect to the fuselage.
Claim 3
Dependent Claim
90 words
A vibration absorber according to claim 1 wherein said dynamic mass member is a basically flat member of rectangular cross section having a longitudinal axis and lateral axis and shaped so that the mass center of gravity is at the geometric center thereof, and wherein the said center spring member is connected to the mass member a selected distance from the mass center of gravity, and wherein said side spring members are connected to the mass member a selected distance on the opposite side of the mass center of gravity.
Claim 4
Dependent Claim
180 words
A vibration absorber according to claim 2 wherein said mass member longitudinal and lateral axes pass through the mass center of gravity and geometric center, wherein each of said spring members has a central axis about which each said spring member is symmetric and wherein said spring members are positioned so that their central axes are parallel and parallel to the mass member longitudinal axis, further wherein the central axis of said center spring member extends along said mass member longitudinal axis, and the central axis of said end spring members are positioned equidistant on opposite sides of said mass member longitudinal axis, and wherein said second connecting means connects the wide end of said center spring member to said mass member a selected distance from said mass member lateral axis and wherein said second connecting means connects the wide ends of each of said side spring members to said mass member at the same selected distance on the opposite side of said mass member lateral axis, and at equal distances on opposite sides of said mass member longitudinal axis.
Claim 5
Dependent Claim
35 words
A helicopter according to claim 1 wherein said first connecting means connects said spring members to said fuselage so that said mass member is able to move along said longitudinal axis relative to the fuselage.
Claim 6
Dependent Claim
92 words
A vibration absorber according to claim 4 wherein said second connecting means comprises flange members intergally connected to the wide ends of each of said spring members so as to be oriented parallel to said mass member flat surface and having two parallel rows of bolt holes passing therethrough parallel to said mass member lateral axis, and bolt members passing through said aligned holes in said flange members and said mass member so that all forces and moments may be transmitted between said mass member and said spring members in all directions.
Claim 7
Dependent Claim
41 words
A vibration absorber according to claim 5 wherein said mass member includes beveled portions shaped to the shape of the spring members so that said mass member is able to move relative to said fuselage without interference from said spring members.
Claim 8
Dependent Claim
52 words
A vibration absorber according to claim 1 wherein said first means connects said spring members and hence said vibration absorber to the fuselage directly at three points of attachment therebetween, and wherein said first means includes three bolt members whose insertion or removal mounts or removes the vibration absorber from the fuselage.
Claim 9
Dependent Claim
24 words
A vibration absorber according to claim 7 wherein said first means comprise spherical bearing connections between the spring member narrow end and the fuselage.
References Cited (Backward Citations)
US3066905A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-28 | 1984-04-28 | 1984-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-28 | 1988-04-28 | 1988-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-28 | 1992-04-28 | 1992-10-28 | $7700.00 | Window Closed / Lapsed |