US3611084A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective cycle motor winding for movie projector
Assignee: GAF Corp
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Filing: 1969-12-29
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Granted: 1971-10-05
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Expires: 1989-12-29
Abstract
Abstract This application discloses a motion picture projector driven by an alternating current motor. The motor by manipulation of a switch altering the effective number of turns in the field winding can operate at different frequencies without undesirable variations in speed, torque and temperature.
Inventors
- 👤 George C Kent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:40
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/18
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
157 words
In a motion picture projector having a lamp, a lens, a delivery reel, a takeup reel and guide means over which film may be trained between said lamp and said lens from said delivery to said takeup reel, and drive means for said takeup reel; the improvement comprising an electric motor, transmission means connecting said motor and said drive means, said motor having a winding, means for connecting said winding to a source of alternating current supply, including a plurality of taps connected to said winding and switch means for selectively connecting one side of the source to one of said tapes and a conductor for connecting an end of said winding spaced from said taps to the other side of said source for varying the effective turns in said winding as the supply frequency changes whereby the impedance of said winding is maintained substantially constant in spite of changes in the frequency of the supply voltage.
Claim 2
Dependent Claim
157 words
In a motion picture projector having a lamp, a lens, a delivery reel, a takeup reel and guide means over which film may be trained between said lamp and said lens from said delivery to said takeup reel, and drive means for said takeup reel; the improvement comprising an electric motor, transmission means connecting said motor and said drive means, said motor having a winding, means for connecting said winding to a source of alternating current supply, including a plurality of taps connected to said winding and switch means for selectively connecting one side of the source to one of said tapes and a conductor for connecting an end of said winding spaced from said taps to the other side of said source for varying the effective turns in said winding as the supply frequency changes whereby the impedance of said winding is maintained substantially constant in spite of changes in the frequency of the supply voltage.
Claim 3
Dependent Claim
40 words
In the motion picture projector of claim 1 wherein said winding has a first tap intermediate its length for operation at first supply frequency and a second tap at one end thereof for operation at a second and lower frequency.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |