US3597056A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Film movement equalizing device for a motion picture sound projector
Assignee: Sankyo Kogaku Kogyo Co Ltd
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Filing: 1969-07-14
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Granted: 1971-08-03
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Expires: 1989-07-14
Abstract
Abstract A shutter shaft operates film advance means for moving the film past a film gate, and has two pulleys, of different diameters, secured thereto in juxtaposed relation. The pulleys are beltdriven from a small drive pulley on the output shaft of an electric motor, and a solenoid-operated shifter is engaged with the belt to shift the latter between the two differing diameter pulleys. When the belt is engaged with the smaller diameter pulley, the shutter shaft is rotated at 0.5 r.p.m. higher than the average r.p.m. and, when the belt is engaged with the larger diameter pulley, the shutter shaft is rotated at 0.5 r.p.m. lower than the average r.p.m. The motor output shaft contains a drive pulley connected by a belt drive to a flywheel driving a capstan for advancing the film through a sound reproducing section. A film loop is formed between the film gate and the sound reproducing section and a loop size detector is pivotally mounted to engage the film loop. The detector includes an obturator positioned to control the light incident upon a photoelectric transducer in accordance with the size of the film loop. The solenoid operating the belt shifter is controlled by an electric circuit including the photoelectric transducer. In one embodiment, the film may be advanced past a film gate in either a normal direction or a reverse direction, and the loop size detector is conditioned to operate with both directions of film advance, by cam means associated with a shaft controlling a switch which, in turn, controls the direction of operation of the film-driving motor.
Inventors
- 👤 Kenji Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:53
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/08; G03B9/10; G03B19/00; G03B19/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
206 words
A film movement rate equalizing device, for sound projectors having a film gate, for film projection, and a sound reproducing section, said device comprising, in combination, film advance means operable to step the film through said film gate selectively at a first rate, slightly higher than the rate of film movement in said sound reproducing section, or at a second rate, slightly lower than the rate of film movement in said sound reproducing section; film advance rate switching means, operable to switch said film advance means between said first and second rates; signal means controlling rate switching operation of said rate switching means; detecting means movable in accordance with fluctuations in the size of a film loop formed between said film gate and said sound reproducing section, resulting from differences between the rate of film movement through said film gate and the rate of film movement in said sound reproducing section, and operatively associated with said signal means to effect actuation of said signal means, responsive to a detected predetermined fluctuation in the film loop size, to control said rate switching means to switch said film advance means from one said rate to the other said rate; and stop means limiting movement of said detecting means.
Claim 2
Dependent Claim
206 words
A film movement rate equalizing device, for sound projectors having a film gate, for film projection, and a sound reproducing section, said device comprising, in combination, film advance means operable to step the film through said film gate selectively at a first rate, slightly higher than the rate of film movement in said sound reproducing section, or at a second rate, slightly lower than the rate of film movement in said sound reproducing section; film advance rate switching means, operable to switch said film advance means between said first and second rates; signal means controlling rate switching operation of said rate switching means; detecting means movable in accordance with fluctuations in the size of a film loop formed between said film gate and said sound reproducing section, resulting from differences between the rate of film movement through said film gate and the rate of film movement in said sound reproducing section, and operatively associated with said signal means to effect actuation of said signal means, responsive to a detected predetermined fluctuation in the film loop size, to control said rate switching means to switch said film advance means from one said rate to the other said rate; and stop means limiting movement of said detecting means.
Claim 3
Dependent Claim
104 words
A film movement rate equalizing device for sound projectors, as claimed in claim 1, in which said film advance means includes a shutter shaft forming part of a sound projector; two driven pulleys, of respective different diameters, fixed to said shaft in axially juxtaposed relation; shutter shaft driving means including a drive pulley; and a belt trained around said drive pulley and one of said driven pulleys; said film advance rate switching means being operatively associated with said belt and effective, under the control of said signal means, to switch said belt from one driven pulley to the other driven pulley and vice versa.
Claim 4
Dependent Claim
23 words
A film movement rate equalizing device for sound projectors, as claimed in claim 2, in which said driving means is an electric motor.
Claim 5
Dependent Claim
56 words
A film movement rate equalizing device for sound projectors, as claimed in claim 1, in which said signal means includes a photoelectric element and a light source having a light path therebetween; said detecting means including a light path obturator controlling incidence of light from said light source along said light path unto said photoelectric element.
Claim 6
Dependent Claim
217 words
A film movement rate equalizing device for sound projectors, as claimed in claim 4, in which said film advance means is selectively operable to step the film through said film gate in either of two opposite directions; film movement direction switch means operatively connected to said film advance means to selectively change the direction of film feed through said film gate; said stop means being mounted for displacement transversely of said light path to displace the range of movement of said detecting means transversely of said light path; and stop shifting means operatively associated with said film movement direction switch means to displace said stop means in accordance with the direction of film feed through said film gate; the displacing of the range of movement of said detecting means transversely of said light path effecting actuation of said signal means by said detecting means in a manner such that, when the film is moved through the film gate in the reverse direction, the rate of movement of the film, as varied between said first and second rates, is varied in a manner reversed from that in which the rate of movement of the film, as varied between said first and second rates, is varied when the film is advanced in the normal direction through said film gate.
Claim 7
Dependent Claim
227 words
A film movement rate equalizing device for sound projectors, as claimed in claim 4, in which said film advance means is selectively operable to step the film through said film gate in either of two opposite directions; film movement direction switch means operatively associated with said film advance means to switch the direction of movement of film through said film gate from the normal direction to the reverse direction and vice versa; said signal means being mounted for displacement, relative to the range of movement of said detecting means, transversely of said light path; and shifting means operatively associated with said film movement direction switch means and with said signal means and operable to shift said signal means in accordance with the selective direction of film movement through said film gate; the relative position of said signal means with respect to said detecting means, with a selected direction of movement through said film gate, being such that, when the film is advanced in a reverse direction through said film gate, the rate of movement of the film, as varied between said first and second rates, is varied in a manner which is the reverse of the manner in which the rate of movement of the film is varied, between said first and second rates, when the film is advanced in the normal direction through said film gate.
Claim 8
Dependent Claim
69 words
A film movement rate equalizing device for a sound projector as defined in claim 4, in which said detection means has an upper end pivotally supported by a shaft disposed behind said film loop, said detection means having an intermediate portion disposed between said upper and said light path obturator and curved forwardly whereby the detection means can be swung forwardly by the curved surface of the film loop.
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) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |