US4551699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary variable differential transformer
Assignee: Unisys Corp
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Filing: 1985-04-08
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Granted: 1985-11-05
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Expires: 2005-04-08
Abstract
Abstract A rotary variable differential transformer has coil windings at an angle with respect to the longitudinal axis of the transformer and a core rotatable about this axis with end faces cut at projected angles therewith such that a rotation of the core varies the coupling between the primary and secondary windings. Amplitude and phase variations at the secondary windings are measurements of core rotation.
Inventors
- 👤 Joannes N. M. de Jong
- 👤 Richard L. Earle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:27
CPC Classifications
H; H01; H01F; H01F21/00; H01F21/02; H01F21/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
194 words
A rotary variable transformer comprising: electrically coupled first and second coils of electrical conducting material cylindrically wound about a longitudinal axis forming first and second hollow cylinders respectively; a third coil of electrical conducting material positioned between said first and second coils and cylindrically wound about said longitudinal axis forming a third hollow cylinder; first and second rings of circumferentially continuous magnetic susceptible material respectively positioned in said first and second hollow cylinders, each having an extension toward said third hollow cylinder configured to have a circumferential variation of magnetic susceptible material; and a core of circumferentially continuous magnetic susceptible material rotatably positioned in said third hollow cylinder having extensions towards said first and second hollow cylinders configured to have a circumferential variation of magnetic susceptible material to provide maximum magnetic coupling with said extension of said first ring and minimum magnetic coupling with said extension of said second ring for at least one angular rotation position and to provide maximum magnetic coupling to said extension of said second ring and minimum magnetic coupling to said extension of said first ring at preselected angles from each of said at least one angular rotation position.
Claim 2
Dependent Claim
194 words
A rotary variable transformer comprising: electrically coupled first and second coils of electrical conducting material cylindrically wound about a longitudinal axis forming first and second hollow cylinders respectively; a third coil of electrical conducting material positioned between said first and second coils and cylindrically wound about said longitudinal axis forming a third hollow cylinder; first and second rings of circumferentially continuous magnetic susceptible material respectively positioned in said first and second hollow cylinders, each having an extension toward said third hollow cylinder configured to have a circumferential variation of magnetic susceptible material; and a core of circumferentially continuous magnetic susceptible material rotatably positioned in said third hollow cylinder having extensions towards said first and second hollow cylinders configured to have a circumferential variation of magnetic susceptible material to provide maximum magnetic coupling with said extension of said first ring and minimum magnetic coupling with said extension of said second ring for at least one angular rotation position and to provide maximum magnetic coupling to said extension of said second ring and minimum magnetic coupling to said extension of said first ring at preselected angles from each of said at least one angular rotation position.
Claim 3
Dependent Claim
31 words
A rotary variable transformer in accordance with claim 1 wherein said circumferential variation of said first and second rings, and said rotatable core is a diminishing circumferential arc forming a taper.
Claim 4
Dependent Claim
108 words
A rotary variable transformer in accordance with claim 2 wherein said tapers of said first and second ring extensions each form an acute angle with said longitudinal axis and said tapers of said rotatable core extensions form equal and opposite angles with respect to said longitudinal axis having angular values substantially equal to said acute angle, said rotatable core extending from said third hollow cylinder to provide maximum magnetic coupling to said first ring and minimum magnetic coupling to said second ring at a first angular rotation position and maximum magnetic coupling to said second ring at an angular rotation of 180° from said first angular rotation position.
Claim 5
Dependent Claim
110 words
The rotary varible transformer in accordance with claim 2 wherein said tapers of said first and second ring extensions form equal and opposite acute angles with said longitudinal axis and said core extension tapers form acute angles with said longitudinal axis equal to said first and second ring taper acute angles said rotatable core extending from said third hollow cylinder to provide maximum magnetic coupling to said first and minimum magnetic coupling to said second ring at a first angular rotation positon and maximum magnetic coupling to said second ring and minimum magnetic coupling to said first ring at an angular rotation position 180° from said first angular rotation position.
Claim 6
Dependent Claim
151 words
A rotatable variable transformer in accordance with claim 1 wherein said circumferential variation of said first and second ring extensios comprises equal V-notches forming apexes that are positioned at equal rotation angles with respect to a predetermined reference and said rotatable core extensions are V-notched at angles equal to said V-notch angles of said first and second ring extensions to form apexes with predetermined angular separation therebetween, such that maximum magnetic coupling to said first ring and minimum magnetic coupling to said second ring is provided at a first rotation angle and rotation angles thereafter equal to said rotation angle separation of said apexes and maximum magnetic coupling to said second ring and minimum magnetic coupling to said first ring is provided at a rotation angle equal to said predetermined separation angle from said first rotation angle and at rotation angles thereafter equal to said rotation angle separation of said apexes.
Claim 7
Dependent Claim
16 words
A rotatable variable transformer in accordance with claim 5 wherein said predetermined angular separation is 9°.
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) | 1988-11-04 | 1989-05-06 | 1989-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-04 | 1993-05-06 | 1993-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-04 | 1997-05-06 | 1997-11-05 | $7700.00 | Window Closed / Lapsed |