US5631093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetically coded device
Assignee: Motors Liquidation Co
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Filing: 1991-11-08
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Granted: 1997-05-20
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Expires: 2011-11-08
Abstract
Abstract Nonmagnetized permanent magnet material is heated in a pattern by a laser beam to a localized temperature above the Curie point or a temperature sufficient to reduce the coercivity sufficiently for an external field to magnetize the pattern in the direction of the field. Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength. Alternating pole magnets of this type can be used for stepper motor magnets.
Inventors
- 👤 Thomas A. Perry
- 👤 John R. Bradley
- 👤 Thaddeus Schroeder
- 👤 Carlton D. Fuerst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:44
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/04; C21D1/34; C21D8/00; C21D8/12; C21D8/1294; G; G01; G01D; G01D5/00; G01D5/12; G01D5/244; G01D5/249; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/487; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/0302; H01F1/0306; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/057; H02; H02K; H02K1/00; H02K1/06; H02K1/22; H02K1/27; H02K1/2706; H02K1/272; H02K1/2726; H02K1/2733; H02K15/00; H02K15/02; H02K15/03; C21D1/06; C21D1/09; C21D2221/00; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
114 words
A motor armature comprising a body of permanent magnet material, said body consisting essentially of a motor armature substrate of unmagnetized permanent magnet material and a pattern of magnetized volumes in said substrate which are patterned to define alternate magnetic poles, each pole extending from a surface of the substrate to a depth therein, where each of said magnetized volumes is produced by directing energy onto an unmagnetized substrate surface in a pattern to selectively heat a volume in the substrate to lower its coercivity below the coercivity of the surrounding portion of the substrate; imposing a magnetic field to selectively magnetized the heated volume; and cooling the treated volume in said magnetic field.
Claim 2
Dependent Claim
114 words
A motor armature comprising a body of permanent magnet material, said body consisting essentially of a motor armature substrate of unmagnetized permanent magnet material and a pattern of magnetized volumes in said substrate which are patterned to define alternate magnetic poles, each pole extending from a surface of the substrate to a depth therein, where each of said magnetized volumes is produced by directing energy onto an unmagnetized substrate surface in a pattern to selectively heat a volume in the substrate to lower its coercivity below the coercivity of the surrounding portion of the substrate; imposing a magnetic field to selectively magnetized the heated volume; and cooling the treated volume in said magnetic field.
Claim 3
Dependent Claim
122 words
An annular rotor for an electric motor comprising a body of permanent magnet material, said body consisting essentially of an annular rotor substrate of unmagnetized permanent magnet material and a pattern of magnetized volumes in said substrate which are patterned to define alternate magnetic poles on the rotor periphery, each pole extending from a surface of the substrate to a depth therein, where each of said magnetized volumes is produced by directing energy onto an unmagnetized substrate surface in a pattern to selectively heat a volume in the substrate to lower its coercivity below the coercivity of the surrounding portion of the substrate; imposing a magnetic field to selectively magnetized the heated volume; and cooling the treated volume in said magnetic field.
Claim 4
Dependent Claim
122 words
An annular rotor for an electric motor comprising a body of permanent magnet material, said body consisting essentially of an annular rotor substrate of unmagnetized permanent magnet material and a pattern of magnetized volumes in said substrate which are patterned to define alternate magnetic poles on the rotor periphery, each pole extending from a surface of the substrate to a depth therein, where each of said magnetized volumes is produced by directing energy onto an unmagnetized substrate surface in a pattern to selectively heat a volume in the substrate to lower its coercivity below the coercivity of the surrounding portion of the substrate; imposing a magnetic field to selectively magnetized the heated volume; and cooling the treated volume in said magnetic field.
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) | 2000-05-19 | 2000-11-18 | 2001-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-05-19 | 2004-11-18 | 2005-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-05-19 | 2008-11-18 | 2009-05-20 | $7700.00 | Window Closed / Lapsed |