Patent US3635429A successfully refreshed from Google Patents.
US3635429A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aircraft vibration compensation system
Assignee: Bell Helicopter Textron Inc
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Filing: 1970-03-27
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Granted: 1972-01-18
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Expires: 1990-03-27
Abstract
Abstract Apparatus is disclosed that minimizes the effect of rotor blade induced vibratory disturbances at the pilot''s seat and in the cabin of an aircraft. The apparatus generates a reciprocating force which is applied to the aircraft to modify the mode of vibration of the fuselage in such a fashion that the magnitude of the vibration disturbance at any selected area of the fuselage, such as at the pilot''s seat, is minimized. The compensatory reciprocating force is developed by vibrating a mass mounted on the fuselage. A control signal equal in frequency to the disturbing rotor blade vibration is applied to the vibrating mass, to cause it to reciprocate relative to the fuselage at a frequency equal to the undesired disturbing vibration. Pilot or automatic variation of the phase and amplitude of the control signal permits the pilot to achieve a minimum felt vibratory disturbance at the pilot''s seat.
Inventors
- 👤 Rodney W Balke
- 👤 David L Kidd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:13
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/001; B64C2027/004; B64C2027/005
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
180 words
In a rotary wing aircraft having a fuselage, a rotor and rotor blade assembly rotatable with respect to the fuselage, the improvement of a system to compensate for vibratory forces generated by rotation of the rotor blade comprising: a. a signal generating means coupled to the rotor blade assembly for producing a first signal having at least one frequency component equal to that of a first one of the rotor blade assembly generated vibratory forces, b. a mass mounted on said fuselage for reciprocal motion relative to said fuselage, and c. control means coupled to said mass for causing said mass to produce compensating vibratory forces in the fuselage at a predetermined location therein which is removed from the location in the fuselage at which the vibratory forces generated by the rotor blade assembly and said mass are directly applied, said control means controlling said mass in response to said first signal and vibratory forces caused at a predetermined location by the vibratory forces of the rotor blade assembly, whereby the mode of vibration of said fuselage will be modified.
Claim 2
Dependent Claim
180 words
In a rotary wing aircraft having a fuselage, a rotor and rotor blade assembly rotatable with respect to the fuselage, the improvement of a system to compensate for vibratory forces generated by rotation of the rotor blade comprising: a. a signal generating means coupled to the rotor blade assembly for producing a first signal having at least one frequency component equal to that of a first one of the rotor blade assembly generated vibratory forces, b. a mass mounted on said fuselage for reciprocal motion relative to said fuselage, and c. control means coupled to said mass for causing said mass to produce compensating vibratory forces in the fuselage at a predetermined location therein which is removed from the location in the fuselage at which the vibratory forces generated by the rotor blade assembly and said mass are directly applied, said control means controlling said mass in response to said first signal and vibratory forces caused at a predetermined location by the vibratory forces of the rotor blade assembly, whereby the mode of vibration of said fuselage will be modified.
Claim 3
Dependent Claim
28 words
The system of claim 1 wherein said control means includes amplitude control means for varying the amplitude of the reciprocating force applied by said mass to said fuselage.
Claim 4
Dependent Claim
28 words
The system of claim 1 wherein said control means includes phase control means for varying the phase of the reciprocating force applied by said mass to said fuselage.
Claim 5
Dependent Claim
28 words
The system of claim 2 wherein said control means includes phase control means for varying the phase of the reciprocating force applied by said mass to said fuselage.
Claim 6
Dependent Claim
57 words
The system of claim 1 wherein said Mass is mounted on said fuselage through first and second power elements, said mass being fixedly mounted on said first power element, said second power element being fixedly mounted on said fuselage, said power elements being adapted to move reciprocally relative to one another in response to said control means.
Claim 7
Dependent Claim
18 words
The system of claim 5 wherein said power elements are a piston with associated rod and a cylinder.
Claim 8
Dependent Claim
92 words
The system of claim 1 wherein: said signal generating means includes a first pickoff means to produce said first signal having a frequency equal to the frequency of the one per rev vibratory disturbance, and a second pickoff means to provide a second signal having a frequency equal to the frequency of the two per rev vibratory disturbance, said control means including means for combining said first signal having said first frequency and said second control having said second frequency into a composite control signal to control the reciprocation of said mass.
Claim 9
Dependent Claim
35 words
The system of claim 7 wherein said control means includes first amplitude control means for varying he amplitude of said first signal and second amplitude control means for varying the amplitude of said second signal.
Claim 10
Dependent Claim
36 words
The system of claim 7 wherein said control means includes first phase control means for varying the phase of said first signal and the second phase control means for varying the phase of said second signal.
Claim 11
Dependent Claim
35 words
The system of claim 9 wherein said control means includes first amplitude control means for varying the amplitude of said first signal and second amplitude control means for varying the amplitude of said second signal.
References Cited (Backward Citations)
US3514054A
Cited
US3497164A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |