US3704941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motion picture projector
Assignee: Agfa Gevaert AG
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Filing: 1970-12-17
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Granted: 1972-12-05
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Expires: 1990-12-17
Abstract
Abstract A motion picture projector for use with film wherein the light transmissivity of the leading and trailing film portions is less than the light transmissivity of the median or main film portion. The film is scanned by one or more photoelectric receivers which produce signals in response to detection of the main film portion while the film is moved forwardly whereby such signals cause the film transporting mechanism to reduce the speed of forward transport of the film to normal speed. The receiver or receivers can also produce signals in response to detection of the trailing film portion whereby such signals initiate automatic reversal in the direction of film transport so that the film is collected by the supply reel. The signals which are produced in response to detection of the main film portion can also cause the claw pulldown to begin with stepwise transport of film past the gate, a shutter to permit entry of light into the projection lens system, a film threading mechanism to move away from the supply reel, a pressure plate to move against the film, and/or a deflecting mechanism for the tip of the leading film portion to assume an inoperative position. Signals which are produced in response to detection of the trailing portion of the film can further cause a shutter to move between the lens system and the light source, to automatically arrest the rewinding drive with a desired delay, and/or to open the circuit of the light source.
Inventors
- 👤 Alfred Winkler
- 👤 Johann Zanner
- 👤 Bernhard V Fischern
- 👤 Klaus Fuchsle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:55
CPC Classifications
G; G03; G03B; G03B1/00; G03B1/56; G03B21/00; G03B21/14; G03B21/32; G03B21/43
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
349 words
In a cinematographic apparatus for use with motion picture film having a leading first portion, a trailing second portion and a main portion whose light transmissivity normally fluctuates and normally differs from the light transmissivity of said first and second portions, a combination comprising first and second photoelectric scanning means for scanning the film and for producing signals indicative of the light transmissivity of the scanned film portions; a plurality of adjustable units including transporting means for moving the film past said scanning means, and transporting means being arranged to move the film at a plurality of speeds and including first output means actuatable to move the film forwardly and second output means actuatable to move the film rearwardly; and means for adjusting at least one of said units in response to signals from said scanning means, including a control circuit connected with said first scanning means, means for reducing the speed of film transport by said transporting means in response to detection of said main film portion by said first scanning means following the completed scanning of said first film portion, said speed reducing means including first electromagnet means connected with said control circuit and having its condition of energization changed in response to detection of said main film portion by said first scanning means whereby said change in the condition of said first electromagnet means initiates said reduction in the speed of film transport by said transporting means, second electromagnet means for deactivating said first output means and for activating said second output means in response to detection of said second film portion by said second scanning means subsequent to completed scanning of said main film portion, and means for preventing a deactivation of said first output means in response to fluctuations in the light transmissivity of said main film portion, means for preventing a deactivation of said first output means in response to fluctuations in the light transmissivity of said main film portion, and means for preventing the activation of said second output means during transport of said first film portion past said second scanning means.
Claim 2
Dependent Claim
349 words
In a cinematographic apparatus for use with motion picture film having a leading first portion, a trailing second portion and a main portion whose light transmissivity normally fluctuates and normally differs from the light transmissivity of said first and second portions, a combination comprising first and second photoelectric scanning means for scanning the film and for producing signals indicative of the light transmissivity of the scanned film portions; a plurality of adjustable units including transporting means for moving the film past said scanning means, and transporting means being arranged to move the film at a plurality of speeds and including first output means actuatable to move the film forwardly and second output means actuatable to move the film rearwardly; and means for adjusting at least one of said units in response to signals from said scanning means, including a control circuit connected with said first scanning means, means for reducing the speed of film transport by said transporting means in response to detection of said main film portion by said first scanning means following the completed scanning of said first film portion, said speed reducing means including first electromagnet means connected with said control circuit and having its condition of energization changed in response to detection of said main film portion by said first scanning means whereby said change in the condition of said first electromagnet means initiates said reduction in the speed of film transport by said transporting means, second electromagnet means for deactivating said first output means and for activating said second output means in response to detection of said second film portion by said second scanning means subsequent to completed scanning of said main film portion, and means for preventing a deactivation of said first output means in response to fluctuations in the light transmissivity of said main film portion, means for preventing a deactivation of said first output means in response to fluctuations in the light transmissivity of said main film portion, and means for preventing the activation of said second output means during transport of said first film portion past said second scanning means.
Claim 3
Dependent Claim
39 words
A combination as defined in claim 1, wherein said first scanning means comprises photoelectric receiver means and said control circuit having an input portion connected with said receiver means and an output portion, connected with said first electromagnet means.
Claim 4
Dependent Claim
45 words
A combination as defined in claim 1, further comprising a cassette containing a supply of convoluted motion picture film, said transporting means being arranged to advance the leading and second portions and thereupon the main portion of the film in the cassette past scanning means.
Claim 5
Dependent Claim
67 words
A combination as defined in claim 1, wherein said transporting means is arranged to transport the film along a predetermined path and said first scanning means comprises a photoelectric receiver adjacent to one side of said path and a light source lOcated at the other side of said path and arranged to direct a beam of light through the film in said path and against said receiver.
Claim 6
Dependent Claim
18 words
A combination as defined in claim 4, wherein said light source is the projector lamp of said apparatus.
Claim 7
Dependent Claim
89 words
A combination as defined in claim 5, further comprising a gate adjacent to said other side of said path and having a window for passage of light from said source through the lens system of the apparatus and an aperture located upstream of said window, as considered in the direction of film transport along said path while the film is being drawn from a source of supply, said aperture being positioned to transmit said beam of light against the film in said path and being located opposite said receiver.
Claim 8
Dependent Claim
56 words
A combination as defined in claim 1, further comprising a supply reel for motion picture film, said transporting means further including means for rotating said supply reel and said adjusting means being arranged to disengage said transporting means from said supply reel in response to detection by said first scanning means of said means film portion.
Claim 9
Dependent Claim
27 words
A combination as defined in claim 7, wherein said film transporting means is arranged to rotate the supply reel in a direction to pay out the film.
Claim 10
Dependent Claim
71 words
A combination as defined in claim 1, further comprising a supply reel for convoluted motion picture film and a takeup reel, said transporting means being arranged to advance the film between said reels along a predetermined path extending along said scanning means and said first electromagnet means being arranged to reduce the speed of said takeup reel in response to detection by said first scanning means of said main film portion.
Claim 11
Dependent Claim
41 words
A combination as defined in claim 1, wherein said transporting means is arranged to advance the film along a predetermined path and another of said unit a includes pressure plate means movable with reference to said path by said adjusting means.
Claim 12
Dependent Claim
21 words
A combination as defined in claim 10 wherein said pressure plate means is movable by said adjusting means toward said path.
Claim 13
Dependent Claim
56 words
A combination as defined in claim 1, wherein the film is provided with at least one row of perforations and another of said units comprises pull-down means having claw means movable by said adjusting means into engagement with the perforations of film in response to detection by said first scanning means of said main film portion.
Claim 14
Dependent Claim
110 words
A combination as defined in claim 1, further comprising a light source and a lens system through which the light from said source passes during the projection of images of frames on the film, another of said units comprising masking means movable between two positions in one of which it obstructs the passage of light to said lens system and in the other of which it permits light to pass from said source to said lens system, said adjusting means being arranged to move said masking means from one of said positions to the other position in response to detection by said first scanning means of said main film portion.
Claim 15
Dependent Claim
20 words
A combination as defined in claim 1, wherein said control circuit includes a switching stage having a plurality of transistors.
Claim 16
Dependent Claim
14 words
A combination as defined in claim 1 wherein said control circuit includes thyristor means.
Claim 17
Dependent Claim
94 words
A combination as defined in claim 1, wherein said transporting means includes a reversible drive including said first and said second output means, said drive further including a prime mover and control means normally coupling said prime mover with said first output means and arranged to disconnect the prime mover from said first output means to thus deactivate said first output means and to simultaneously connect the prime mover with said second output means under the action of said second electromagnet means when said second scanning means begins to scan said second film portion.
Claim 18
Dependent Claim
51 words
A combination as defined in claim 16, wherein said second scanning means comprises photoelectric receiver means adJacent to the path of the film and said adjusting means further comprises a second control circuit having an input connected with said receiver means and an output operatively connected with said second electromagnet means.
Claim 19
Dependent Claim
16 words
A combination as defined in claim 17, wherein said second control circuit is a transistorized circuit.
Claim 20
Dependent Claim
54 words
A combination as defined in claim 18, wherein said second control circuit comprises third electromagnet means energizable in response to detection of said second portion of film by said second scanning means and switch means which is closed in response to energization of said third electromagnet means to thereby energize said second electromagnet means.
Claim 21
Dependent Claim
36 words
A combination as defined in claim 16, wherein said drive further comprises coupling means and said control means is arranged to engage said coupling means in response to reception of motion from said second electromagnet means.
Claim 22
Dependent Claim
42 words
A combination as defined in claim 16, wherein said reversible drive further comprises normally engaging coupling means which is disengaged by said second electromagnet means with a delay following deactivation of said second output means to thereby terminate the rewinding of film.
Claim 23
Dependent Claim
48 words
A combination as defined in claim 1, wherein said second scanning means comprises a photoelectric receiver and said adjusting means further comprises a second control circuit including capacitor means and means for connecting said capacitor means in parallel with said receiver, said capacitor means constituting said preventing means.
Claim 24
Dependent Claim
42 words
A combination as defined in claim 1, wherein said second means comprises photoelectric receiver means and said adjusting means further comprises a second control circuit having an input connected with said receiver means and a switching stage including a plurality of transistors.
Claim 25
Dependent Claim
72 words
A combination as defined in claim 1, wherein said second scanning means comprises photoelectric receiver means and said adjusting means further comprises a second control circuit having an input connected with said receiver means, a source of electrical energy, and an electric delay circuit having switch means for connecting said second control circuit to said energy source with a predetermined delay following detection of said second film portion by said receiver means.
Claim 26
Dependent Claim
61 words
A combination as defined in claim 24, wherein said delay circuit further comprises an output including third electromagnet means energizable to actuate said switch means, a switching unit for energizing said third electromagnet means, and an input including an RC-unit connected with said switching unit, said R-C unit including resistor means and capacitor means connected in series with said resistor means.
Claim 27
Dependent Claim
25 words
A combination as defined in claim 25, further comprising second switch means actuatable by the film to connect said delay circuit with said energy source.
Claim 28
Dependent Claim
26 words
A combination as defined in claim 25, further comprising third switch means for shunting said capacitor means in response to removal of film from the apparatus.
Claim 29
Dependent Claim
53 words
A combination as defined in claim 16, wherein said second scanning means comprises at least one photoelectric receiver and a light source for directing a beam of light across the film path against said receiver, and further comprising means for intercepting said light beam in response to reversal of operation of said drive.
Claim 30
Dependent Claim
29 words
A combination as defined in claim 16, further comprising a light source and means for turning off said light source in response to reversal of operation of said drive.
References Cited (Backward Citations)
US1944024A
Cited
US3573392A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-05 | 1976-06-05 | 1976-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-05 | 1980-06-05 | 1980-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-05 | 1984-06-05 | 1984-12-05 | $7700.00 | Window Closed / Lapsed |