US3677455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Film advancing device
Assignee: Eastman Kodak Co
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Filing: 1970-10-01
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Granted: 1972-07-18
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Expires: 1990-10-01
Abstract
Abstract A motion picture projector having selectively operable means for intermittently moving film through a projection gate in either forward or reverse directions and for continuously moving film through the gate for rewind operation includes a device for advancing film between a supply roll and the gate in forward projection, reverse projection and rewind modes of operation of the projector. Film is advanced by the device through a channel defined by at least one rotatable roller and wall means spaced apart sufficiently to permit an excess of film to build up ahead of the gate. The channel defining means may be coated with a high friction material so that during forward projection when film is pushed into the channel from the supply roll by a tendency drive mechanism, contact between the film and the high friction material coating prevents movement of more film into the channel by the tendency drive than is withdrawn from the other end of the channel by the intermittent film moving means. During reverse projection operation of the projector, contact of the film with the high friction material attenuates the force applied to the film by the tendency drive and prevents that force from reaching the film in the gate. The force attenuating effect is reduced during threading and rewind operation by permitting the roller to be rotated by the film passing thereover.
Inventors
- 👤 Robert B Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:22
CPC Classifications
G; G03; G03B; G03B1/00; G03B1/42; G03B21/00; G03B21/14; G03B21/32; G03B21/43
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
150 words
A device for advancing film from a supply roll to a film gate, said film advancing device comprising: means for advancing film through the film gate; a member positioned to engage the film between the supply roll and the gate without slippage, said member being movable to push film toward the gate; power means for moving said member; means interconnecting said power means and said member for limiting the force applied to the film by said member; means for guiding the film from said member to the gate with a confined free length of film between said member and the film advance means; and force attenuation means frictionally engaging the film in said guide means for resisting more movement of film into said guide means than is withdrawn by the intermittent film advance means, whereby force applied to the film by said member is partially attenuated in said guide means.
Claim 2
Independent Claim
150 words
A device for advancing film from a supply roll to a film gate, said film advancing device comprising: means for advancing film through the film gate; a member positioned to engage the film between the supply roll and the gate without slippage, said member being movable to push film toward the gate; power means for moving said member; means interconnecting said power means and said member for limiting the force applied to the film by said member; means for guiding the film from said member to the gate with a confined free length of film between said member and the film advance means; and force attenuation means frictionally engaging the film in said guide means for resisting more movement of film into said guide means than is withdrawn by the intermittent film advance means, whereby force applied to the film by said member is partially attenuated in said guide means.
Claim 3
Dependent Claim
72 words
A device as defined in claim 1 wherein: said guide means comprises two opposed walls forming a channel, said walls being spaced sufficiently from each other to permit accumulation in the channel of a length of film that is longer than the channel; and said force attenuation means comprises a high friction material on said walls For contacting and frictionally restraining the film when the accumulated film length exceeds a predetermined size.
Claim 4
Dependent Claim
71 words
A device as defined in claim 1 wherein: said guide means comprises two opposed walls forming a chennal said walls being spaced sufficiently form each other to permit the film to buckle into a wavy configuration to form a plurality of buckles; and said force attenuation means comprising a high friction material on said walls for contacting and frictionally restraining the film when said plurality of buckles exceed a predetermined size.
Claim 5
Dependent Claim
92 words
A device as defined in claim 1 wherein: said guide means comprises two opposed walls forming a sinuous channel, said walls being spaced sufficiently from each other to permit accumulation in the channel of a length of film that is longer than the channel but sufficiently close to each other to prevent buckling of the film into a wavy configuration within said channel; and said force attenuation means comprises a high friction material on said walls for contacting and frictionally restraining the film when the accumulated film length exceeds a predetermined size.
Claim 6
Dependent Claim
14 words
A device as defined in claim 1 wherein said member is a sprocket wheel.
Claim 7
Independent Claim
155 words
A device for advancing film from a supply roll to a film gate having pressure means for preventing film from moving through the gate when pushed with a force below a first value, said film advancing device comprising: means for advancing film through the film gate at a first rate; a member positioned to engage the film between the supply roll and the gate without slippage, said member being movable to push film toward the gate; power means for moving said member at a rate to push film toward the gate at least as fast as said first rate; means frictionally interconnecting said power means and said member for limiting the force applied to the film by said member to a second value greater than the first value; and means between said member and the gate for attenuating the force applied to the film by said member to a value less than the first value.
Claim 8
Independent Claim
155 words
A device for advancing film from a supply roll to a film gate having pressure means for preventing film from moving through the gate when pushed with a force below a first value, said film advancing device comprising: means for advancing film through the film gate at a first rate; a member positioned to engage the film between the supply roll and the gate without slippage, said member being movable to push film toward the gate; power means for moving said member at a rate to push film toward the gate at least as fast as said first rate; means frictionally interconnecting said power means and said member for limiting the force applied to the film by said member to a second value greater than the first value; and means between said member and the gate for attenuating the force applied to the film by said member to a value less than the first value.
Claim 9
Dependent Claim
66 words
A device as defined in claim 6 wherein said force attenuating means comprises: means for guiding the film from said member to the gate with a confined free length of film between said member and the intermittent film advance means; and means for frictionally engaging the film in said guide means for resisting pushing of the film when said member urges film into said guide means.
Claim 10
Dependent Claim
133 words
In a motion picture apparatus, a device for advancing film through a threading path from a film gate to a film roll, said film advancing device comprising: means for guiding the film from the gate to the roll; means selectively operable for intermittently or continuously moving film from the gate into said guide means, said film moving means including tendency drive means for applying a force to the film to pull from said guide means a length of film corresponding to that fed intermittently into said guide means; force attenuation means positioned to frictionally engage the film in said guide means for resisting movement of film by said tendency drive means during intermittent operation of said moving means; and means for disabling said force attenuation means during continuous operation of said moving means.
Claim 11
Dependent Claim
133 words
In a motion picture apparatus, a device for advancing film through a threading path from a film gate to a film roll, said film advancing device comprising: means for guiding the film from the gate to the roll; means selectively operable for intermittently or continuously moving film from the gate into said guide means, said film moving means including tendency drive means for applying a force to the film to pull from said guide means a length of film corresponding to that fed intermittently into said guide means; force attenuation means positioned to frictionally engage the film in said guide means for resisting movement of film by said tendency drive means during intermittent operation of said moving means; and means for disabling said force attenuation means during continuous operation of said moving means.
Claim 12
Dependent Claim
61 words
A device as defined in claim 8 wherein: said guide means includes spaced walls defining a curved channel; and said force attenuation means comprises a high friction material on at least one of said walls for contacting and frictionally restraining the film when said tendency drive means pulls the film against said one wall during intermittent operation of said moving means.
Claim 13
Dependent Claim
22 words
A device as defined in claim 9 wherein said disabling means comprises means permitting said one wall to move with the film.
Claim 14
Dependent Claim
243 words
In a motion picture projector having a film gate and means for receiving a film roll, a device for advancing film between the gate and the roll in foRward project, reverse project and rewind modes of operation of the projector, said film advancing device comprising: means selectively operable for intermittently advancing film through the gate in first and second directions for forward and reverse projection operation of the projector, respectively, or for continuously advancing film through the gate for rewind operation of the projector; means between the gate and the roll defining a curved channel through which film is guided, said channel defining means including at least one rotatable roller having a high friction surface about which the film is at least partially wrapped; tendency drive means between said channel and the roll for pushing film into said channel during forward project operation of the projector and for applying a force to the film to pull from said channel a length of film corresponding to that advanced through the gate during reverse project and rewind operation of the projector; force attenuation means frictionally engaging the film in said channel for resisting more movement of film into said channel by said tendency drive means than is withdrawn by said selectively operable means during forward project operation of the projector; and means preventing rotation of said roller during reverse projection operation of the projector and for permitting such rotation during rewind operation of said projector.
Claim 15
Dependent Claim
243 words
In a motion picture projector having a film gate and means for receiving a film roll, a device for advancing film between the gate and the roll in foRward project, reverse project and rewind modes of operation of the projector, said film advancing device comprising: means selectively operable for intermittently advancing film through the gate in first and second directions for forward and reverse projection operation of the projector, respectively, or for continuously advancing film through the gate for rewind operation of the projector; means between the gate and the roll defining a curved channel through which film is guided, said channel defining means including at least one rotatable roller having a high friction surface about which the film is at least partially wrapped; tendency drive means between said channel and the roll for pushing film into said channel during forward project operation of the projector and for applying a force to the film to pull from said channel a length of film corresponding to that advanced through the gate during reverse project and rewind operation of the projector; force attenuation means frictionally engaging the film in said channel for resisting more movement of film into said channel by said tendency drive means than is withdrawn by said selectively operable means during forward project operation of the projector; and means preventing rotation of said roller during reverse projection operation of the projector and for permitting such rotation during rewind operation of said projector.
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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |