US3735219A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal protection device for linear motor
Assignee: Memorex Corp
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Filing: 1971-08-25
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Granted: 1973-05-22
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Expires: 1991-08-25
Abstract
Abstract Thermal protection apparatus is disclosed for electrical motors and, in particular, for a linear motor as, for example, the type used in magnetic disc recording drive systems. An electrical circuit, the analog of the thermal characteristics of the armature coil, provides electrical signals indicative of the temperature of the armature coil. Safety or protection means responsive to these electrical signals maintains the motor armature coil below a safe, predetermined level, by, in the preferred embodiment, reducing the average power input to the motor.
Inventors
- 👤 M Kahn
- 👤 W Krajewski
- 👤 T Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:02
CPC Classifications
H; H02; H02H; H02H6/00; G; G11; G11B; G11B5/00; G11B5/48; G11B5/54; G11B5/55; G11B5/5521; G11B5/5526; G11B5/553; H02H7/00; H02H7/08; H02H7/085
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
163 words
In a magnetic disc drive assembly including a linear motor for moving and positioning one or more record/play heads adjacent to one or more recording tracks on one or more magnetic recording discs, said linear motor including a stationary permanent magnet and a movable armature coil forming a bobbin, and control means for controlling the linear position of said bobbin, and wherein the improvement comprises: a. electrical analog means having an electrical input and an electrical output and circuit means connected between said input and output having a time response matched to the time response of the heat transfer characteristics of said armature coil for providing electrical analog signals corresponding to the temperature of the armature coil with the input of said electrical analog means connected to said coil for sensing the non-thermal electrical conditions in said coil; and b. protective means connected to the output of said electrical analog signals for maintaining the temperature of the armature coil below a predetermined limit.
Claim 2
Dependent Claim
163 words
In a magnetic disc drive assembly including a linear motor for moving and positioning one or more record/play heads adjacent to one or more recording tracks on one or more magnetic recording discs, said linear motor including a stationary permanent magnet and a movable armature coil forming a bobbin, and control means for controlling the linear position of said bobbin, and wherein the improvement comprises: a. electrical analog means having an electrical input and an electrical output and circuit means connected between said input and output having a time response matched to the time response of the heat transfer characteristics of said armature coil for providing electrical analog signals corresponding to the temperature of the armature coil with the input of said electrical analog means connected to said coil for sensing the non-thermal electrical conditions in said coil; and b. protective means connected to the output of said electrical analog signals for maintaining the temperature of the armature coil below a predetermined limit.
Claim 3
Dependent Claim
65 words
Magnetic disc drive assembly as in claim 1 wherein said circuit means of said electrical analog means comprises: a. means for monitoring the power input to said armature coil; b. an electrical circuit providing an analog of the thermal characteristics of said armature coil, said electrical circuit being responsive to said monitoring means for providing electrical signals corresponding to the temperature of said armature coil.
Claim 4
Dependent Claim
24 words
Magnetic disc drive assembly as in claim 2 wherein said protection means comprises means for reducing the average power input to said armature coil.
Claim 5
Dependent Claim
25 words
Magnetic disc drive assembly as in claim 3 wherein said power reducing means comprises means for increasing the time duration between armature coil actIvation cycles.
Claim 6
Dependent Claim
40 words
Magnetic disc drive assembly as in claim 4 wherein the time duration is a length of time selected to permit sufficient cooling so that the temperature of the coil stays below said predetermined limit even in the worst heating situations.
Claim 7
Dependent Claim
24 words
Magnetic disc drive assembly as in claim 1 wherein said protection means comprises means for reducing the average power input to said armature coil.
Claim 8
Dependent Claim
24 words
Magnetic disc drive assembly as in claim 2 wherein said power reducing means comprises means for increasing the time duration between coil activation cycles.
Claim 9
Dependent Claim
40 words
Magnetic disc drive assembly as in claim 4 wherein the time duration is a length of time selected to permit sufficient cooling so that the temperature of the coil stays below said predetermined limit even in the worst heating situations.
Claim 10
Dependent Claim
114 words
Thermal protection apparatus for a motor having an armature coil comprising: a. means for monitoring the input power to said motor; b. electrical circuit means having an electrical input and an electrical output and circuit means connected between said input and output having a time response matched to the time response of the heat transfer characteristics of said armature coil for providing an electrical analog of the thermal characteristics of said armature coil, said circuit means being responsive to said monitoring means for providing electrical signals indicative of the temperature of said coil, and c. safety means responsive to said temperature signals for maintaining the temperature of said coil below a predetermined safe level.
Claim 11
Dependent Claim
114 words
Thermal protection apparatus for a motor having an armature coil comprising: a. means for monitoring the input power to said motor; b. electrical circuit means having an electrical input and an electrical output and circuit means connected between said input and output having a time response matched to the time response of the heat transfer characteristics of said armature coil for providing an electrical analog of the thermal characteristics of said armature coil, said circuit means being responsive to said monitoring means for providing electrical signals indicative of the temperature of said coil, and c. safety means responsive to said temperature signals for maintaining the temperature of said coil below a predetermined safe level.
Claim 12
Dependent Claim
22 words
Thermal protection apparatus as in claim 9 wherein said safety means includes means for reducing the average input power to said motor.
Claim 13
Dependent Claim
19 words
Thermal protection apparatus as in claim 9 wherein said monitoring means comprises means for sampling the motor armature current.
Claim 14
Dependent Claim
43 words
Thermal protection apparatus as in claim 10 wherein said motor is a linear motor having a movable armature coil which is periodically energized for linear positioning, and wherein said power reducing means comprises means for increasing the time duration between coil activation cycles.
Claim 15
Dependent Claim
39 words
Thermal protection apparatus as in claim 12 wherein the time duration is a length of time selected to permit sufficient cooling so that the temperature of the coil stays below said predetermined limit even in the worst heating situations.
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) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |