Patent US4090117A successfully refreshed from Google Patents.
US4090117A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic disc apparatus
Assignee: Hitachi Ltd
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Filing: 1976-09-13
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Granted: 1978-05-16
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Expires: 1996-09-13
Abstract
Abstract In a magnetic disc apparatus of contact-start-stop type, when stopping the rotation of a disc, a brake is placed into operation at the beginning of contact of a magnetic head with a disc at which the number of revolutions of the disc is decreased following turning off of a power source for motor drive. The actuation of an armature of the brake is delayed through the use of a current generated by an inertia rotation of a motor. Thus, wasteful actuation of the brake while the motor is rotating at a high speed is inhibited thereby extending the lifetime of the brake.
Inventors
- 👤 Asao Sasamoto
- 👤 Hideaki Amano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:09
CPC Classifications
H; H02; H02P; H02P3/00; H02P3/02; H02P3/04
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
165 words
A magnetic disc apparatus comprising: a magnetic disc; terminal means for receiving an electric supply; an induction motor connected to said terminal means for rotating said disc, said motor being provided with a first capacitor which is operative at the start of said motor and a second capacitor which is operative constantly; an electromagnetic brake connected to said terminal means and adapted to be placed into operation for stopping rotation of said motor when deenergized; and a delay relay connected in parallel with said electromagnetic brake and having a normally-closed contact, said first capacitor being connected in parallel with said second capacitor through said normally-closed contact, whereby when said electric supply is cut off from said terminal means said normally-closed contact is closed and the starting time for placing said electromagnetic brake into operation is delayed by supplying said electromagnetic brake with a current generated by said motor due to an inertia rotation thereof upon the cutting-off of said electric supply from said terminal means.
Claim 2
Dependent Claim
165 words
A magnetic disc apparatus comprising: a magnetic disc; terminal means for receiving an electric supply; an induction motor connected to said terminal means for rotating said disc, said motor being provided with a first capacitor which is operative at the start of said motor and a second capacitor which is operative constantly; an electromagnetic brake connected to said terminal means and adapted to be placed into operation for stopping rotation of said motor when deenergized; and a delay relay connected in parallel with said electromagnetic brake and having a normally-closed contact, said first capacitor being connected in parallel with said second capacitor through said normally-closed contact, whereby when said electric supply is cut off from said terminal means said normally-closed contact is closed and the starting time for placing said electromagnetic brake into operation is delayed by supplying said electromagnetic brake with a current generated by said motor due to an inertia rotation thereof upon the cutting-off of said electric supply from said terminal means.
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) | 1981-05-15 | 1981-11-14 | 1982-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-15 | 1985-11-14 | 1986-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-15 | 1989-11-14 | 1990-05-16 | $7700.00 | Window Closed / Lapsed |