US3588558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic clutch projector drive system
Assignee: Bell and Howell Co
•
Filing: 1969-12-30
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Granted: 1971-06-28
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Expires: 1989-12-30
Abstract
Abstract DRIVE SYSTEM FOR A SYNCHRONIZED MOTION PICTURE PROJECTOR IN WHICH A PROJECTOR DRIVE MECHANISM IS COUPLED THROUGH AN ELECTROMAGNETIC CLUTCH TO A DRIVE MOTOR, PREFERABLY AN INDUCTION MOTOR. THE CLUTCH IS CONTROLLED THROUGH A POWER TRANSISTOR CONTROLLED THROUGH A BUFFER TRANSISTOR FROM A BOOTSTRAP TRANSISTOR INTEGRATOR TO WHICH PULSES ARE APPLIED FROM A FLIP-FLOP RESPONSIVE TO REFERENCE PULSES REPRODUCED FROM MAGNETIC TAPE AND TO PULSES FROM A REED SWITCH OF THE PROJECTOR DRIVE MECHANISM.
Inventors
- 👤 Herman Levin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:52
CPC Classifications
G; G03; G03B; G03B31/00; G03B31/04; H; H02; H02P; H02P5/00; H02P5/46; H02P5/50
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-27 | 1974-12-27 | 1975-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-27 | 1978-12-27 | 1979-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-27 | 1982-12-27 | 1983-06-28 | $7700.00 | Window Closed / Lapsed |