US3870407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Film speed change-over device in a motion picture projector
Assignee: Nikon Corp
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Filing: 1974-06-14
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Granted: 1975-03-11
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Expires: 1994-06-14
Abstract
Abstract A film speed change-over device in a compact motion picture projector employs a cam which rotates at 1/n times the rotational speed of the shutter shaft and a cam follower which, when positioned in engagement with the cam, controls movement of the film-feeding pawl to provide slow-motion projection. The cam follower is axially movable to second and third positions out of engagement with the cam to provide still and normal projection, respectively.
Inventors
- 👤 Shigeo Wakahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:03
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/18; G03B21/00; G03B21/14; G03B21/32; G03B21/43
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
304 words
A film speed change-over device in a motion picture projector having a rotatable shutter shaft, the device comprising: a film-feeding pawl; driving means for moving the film-feeding pawl into a predetermined position to engage a perforation in the film and then for moving the film-feeding pawl in the desired direction of film movement to advance the film a single frame; camming means for rotation at 1/n times the speed of rotation of the shutter shaft, where n is an integer, the camming means providing a camming surface having a radially recessed portion and a radially projecting portion; change-over means including a cam follower biased to engage said camming surface, the cam follower and the camming means being axially movable relative to each other for enabling the cam follower to be moved selectively to a first axial position in engagement with the camming surface and to second and third axial positions out of engagement with the camming surface, the cam follower in said first axial position having a first radial position when received by said recessed portion of the camming surface and a second radial position when engaging said projecting portion of the camming surface; and holding means for holding the cam follower in substantially said first radial position when the cam follower is in said second axial position and for holding the cam follower in substantially said second radial position when the cam follower is in said third axial position, said change-over means having means cooperable with the driving means for permitting movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially one of said first and second radial positions and for preventing movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially the other of said first and second radial positions.
Claim 2
Dependent Claim
304 words
A film speed change-over device in a motion picture projector having a rotatable shutter shaft, the device comprising: a film-feeding pawl; driving means for moving the film-feeding pawl into a predetermined position to engage a perforation in the film and then for moving the film-feeding pawl in the desired direction of film movement to advance the film a single frame; camming means for rotation at 1/n times the speed of rotation of the shutter shaft, where n is an integer, the camming means providing a camming surface having a radially recessed portion and a radially projecting portion; change-over means including a cam follower biased to engage said camming surface, the cam follower and the camming means being axially movable relative to each other for enabling the cam follower to be moved selectively to a first axial position in engagement with the camming surface and to second and third axial positions out of engagement with the camming surface, the cam follower in said first axial position having a first radial position when received by said recessed portion of the camming surface and a second radial position when engaging said projecting portion of the camming surface; and holding means for holding the cam follower in substantially said first radial position when the cam follower is in said second axial position and for holding the cam follower in substantially said second radial position when the cam follower is in said third axial position, said change-over means having means cooperable with the driving means for permitting movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially one of said first and second radial positions and for preventing movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially the other of said first and second radial positions.
Claim 3
Dependent Claim
304 words
A film speed change-over device in a motion picture projector having a rotatable shutter shaft, the device comprising: a film-feeding pawl; driving means for moving the film-feeding pawl into a predetermined position to engage a perforation in the film and then for moving the film-feeding pawl in the desired direction of film movement to advance the film a single frame; camming means for rotation at 1/n times the speed of rotation of the shutter shaft, where n is an integer, the camming means providing a camming surface having a radially recessed portion and a radially projecting portion; change-over means including a cam follower biased to engage said camming surface, the cam follower and the camming means being axially movable relative to each other for enabling the cam follower to be moved selectively to a first axial position in engagement with the camming surface and to second and third axial positions out of engagement with the camming surface, the cam follower in said first axial position having a first radial position when received by said recessed portion of the camming surface and a second radial position when engaging said projecting portion of the camming surface; and holding means for holding the cam follower in substantially said first radial position when the cam follower is in said second axial position and for holding the cam follower in substantially said second radial position when the cam follower is in said third axial position, said change-over means having means cooperable with the driving means for permitting movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially one of said first and second radial positions and for preventing movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially the other of said first and second radial positions.
Claim 4
Dependent Claim
304 words
A film speed change-over device in a motion picture projector having a rotatable shutter shaft, the device comprising: a film-feeding pawl; driving means for moving the film-feeding pawl into a predetermined position to engage a perforation in the film and then for moving the film-feeding pawl in the desired direction of film movement to advance the film a single frame; camming means for rotation at 1/n times the speed of rotation of the shutter shaft, where n is an integer, the camming means providing a camming surface having a radially recessed portion and a radially projecting portion; change-over means including a cam follower biased to engage said camming surface, the cam follower and the camming means being axially movable relative to each other for enabling the cam follower to be moved selectively to a first axial position in engagement with the camming surface and to second and third axial positions out of engagement with the camming surface, the cam follower in said first axial position having a first radial position when received by said recessed portion of the camming surface and a second radial position when engaging said projecting portion of the camming surface; and holding means for holding the cam follower in substantially said first radial position when the cam follower is in said second axial position and for holding the cam follower in substantially said second radial position when the cam follower is in said third axial position, said change-over means having means cooperable with the driving means for permitting movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially one of said first and second radial positions and for preventing movement of the film-feeding pawl into said predetermined position when the cam follower is in substantially the other of said first and second radial positions.
Claim 5
Dependent Claim
37 words
A device as set forth in claim 1, wherein the camming means comprises a generally circular camming plate, and wherein the camming surface comprises substantially the entire axial width of the peripheral surface of the camming plate.
Claim 6
Dependent Claim
43 words
A device as set forth in claim 1, wherein the cam follower is mounted on a change-over member, and wherein the change-over member is axially movable relative to the camming plate for selectively positioning the cam follower in relation to the camming surface.
Claim 7
Dependent Claim
43 words
A device as set forth in claim 3, further comprising a manually operable selection lever having means cooperable with means provided by the change-over member for axially moving the change-over member to selectively position the cam follower in relatiOn to the camming surface.
Claim 8
Dependent Claim
22 words
A device as set forth in claim 1, further comprising detent means for resiliently maintaining the cam follower in the selectable positions.
Claim 9
Dependent Claim
83 words
A device as set forth in claim 3, wherein the holding means comprises a stud having a first diameter portion cooperable with means provided by the change-over member for holding the cam follower in said first radial position when the cam follower is in said second axial position and having a second diameter portion cooperable with said means provided by the change-over member for holding the cam follower in said second radial position when the cam follower is in said third axial position.
Claim 10
Dependent Claim
28 words
A device as set forth in claim 2, wherein the camming surface includes a plurality of recessed portions equally spaced about the peripheral surface of the camming plate.
Claim 11
Dependent Claim
78 words
A device as set forth in claim 7, wherein fewer than all of said plurality of recessed portions extend across substantially the entire axial width of the camming surface for providing a first camming surface portion which includes all of said recessed portions and an adjacent second camming surface portion which includes fewer than all of said recessed portions, and wherein the cam follower is selectively axially movable into engagement with said first and second camming surface portions.
Claim 12
Dependent Claim
81 words
A device as set forth in claim 8, further comprising detent means for resiliently maintaining the cam follower in engagement with said first and second camming surface portions and in said second axial position and for permitting unopposed movement of the cam follower between said third axial position and an intermediate position wherein the cam follower engages one of said first and second camming surface portions, and further comprising biasing means for urging the cam follower into said third axial position.
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) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |