US4422330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low susceptibility proof mass for a single axis drag compensation system
Assignee: United States Department of the Navy
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Filing: 1981-05-07
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Granted: 1983-12-27
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Expires: 2001-05-07
Abstract
Abstract A satellite single axis drag compensation system improves stability and ects damping of movements of a cylindrical proof mass by providing an elongated, perpendicularly magnetized permanent magnet in the core of a current carrying rod that extends coaxially through a central bore of the proof mass, the proof mass being constructed as a composite structure of alternate cylindrical layers of diamagnetic silver and paramagnetic aluminum to reduce magnetic susceptibility thereof.
Inventors
- 👤 Robert E. Fischell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:58
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/02; G01P15/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
161 words
A satellite single axis drag compensation system of the type including a cylindrical proof mass of predetermined length and a longer conductive rod extending coaxially through a central bore of said proof mass and adapted to carry a current for inducing eddy currents in said proof mass for suspension thereof by repulsion forces, said system being characterized by the improvement comprising: an elongate, permanent magnet element, carried by said conductive rod, said element being coaxial with said rod and having a length greater than said predetermined length and being magnetized perpendicularly to its axis and uniformly along its length whereby movements of said proof mass are damped; and said proof mass comprising a plurality of concentric cylindrical layers of conductive material, said layers of conductive material being alternately of diamagnetic and of paramagnetic susceptibility, whereby total susceptibility of said proof mass is below a level that will interact with said permanent magnet element with sufficient force to overcome said repulsion forces.
Claim 2
Dependent Claim
161 words
A satellite single axis drag compensation system of the type including a cylindrical proof mass of predetermined length and a longer conductive rod extending coaxially through a central bore of said proof mass and adapted to carry a current for inducing eddy currents in said proof mass for suspension thereof by repulsion forces, said system being characterized by the improvement comprising: an elongate, permanent magnet element, carried by said conductive rod, said element being coaxial with said rod and having a length greater than said predetermined length and being magnetized perpendicularly to its axis and uniformly along its length whereby movements of said proof mass are damped; and said proof mass comprising a plurality of concentric cylindrical layers of conductive material, said layers of conductive material being alternately of diamagnetic and of paramagnetic susceptibility, whereby total susceptibility of said proof mass is below a level that will interact with said permanent magnet element with sufficient force to overcome said repulsion forces.
Claim 3
Dependent Claim
40 words
A satellite single axis drag compensation system as defined in claim 7, and wherein: said permanent magnet element is in the form of a wire or rod and the magnetization thereof varies by less than about 1% throughout its length.
Claim 4
Dependent Claim
31 words
A satellite single axis drag compensation system as defined in claim 2, and wherein: said permanent magnet element is disposed in an axial central bore of said current carrying conductive rod.
Claim 5
Dependent Claim
34 words
A satellite single axis drag compensation system as defined in claim 3, and wherein: said proof mass comprises outer and inner layers of said diamagnetic material, and an intermediate layer of said paramagnetic material.
Claim 6
Dependent Claim
29 words
A satellite single axis drag compensation system as defined in claim 4, and wherein: said diamagnetic material comprises substantially pure silver; and said paramagnetic material comprises substantially pure aluminum.
Claim 7
Dependent Claim
33 words
A compensation system as defined in claim 4 and wherein: said proof mass is characterized by a mass volume susceptibility that is equal to or less than about 7.8×10 -8 /cm 3 .
Claim 8
Dependent Claim
63 words
An article of manufacture for use in apparatus requiring the article to have low total magnetic susceptibility and low residual magnetism, said article comprising: a composite body including alternate layers of paramagnetic and diamagnetic material, the net paramagnetic susceptibility of said paramagnetic material in said layers being substantially equal in magnitude to the net diamagnetic susceptibility of said diamagnetic material in said layers.
Claim 9
Dependent Claim
63 words
An article of manufacture for use in apparatus requiring the article to have low total magnetic susceptibility and low residual magnetism, said article comprising: a composite body including alternate layers of paramagnetic and diamagnetic material, the net paramagnetic susceptibility of said paramagnetic material in said layers being substantially equal in magnitude to the net diamagnetic susceptibility of said diamagnetic material in said layers.
Claim 10
Dependent Claim
26 words
An article of manufacture as defined in claim 7, and wherein: said diamagnetic material comprises substantially pure silver; and said paramagnetic material comprises substantially pure aluminum.
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) | 1986-12-26 | 1987-06-27 | 1987-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-26 | 1991-06-27 | 1991-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-26 | 1995-06-27 | 1995-12-27 | $7700.00 | Window Closed / Lapsed |