Patent GB-704583-A (GB)
Title: Improvements in and relating to photographic roll-film cameras
IPC: G03B42/02
Filed: 1952-01-14
Abstract: 704,583. Photographic roll-film cameras. VOIGTLANDER AKT.-GES., [formerly VOIGTLANDER & SOHN AKT.-GES.]. Jan. 14, 1952 [Jan. 13, 1951], No. 1062/52. Class 98(1) [Also in Group XXIV] An X-ray roll-film camera for single and serial photographing of a fluorescent screen preferably on a reduced scale having means for automatically winding the film intermittently and for flattening it by pressure against a film gate during exposure is characterized by an electrically driven control mechanism which is brought into action by a current impulse of any desired length, the devices for releasing the film pressure, winding it, and pressing it into position each being brought into action and uncoupled at the completion of its operation individually and in sequence, so that after electric driving members have been set in action by the current impulse, the driving power made available by the driving members is used (1) to actuate, through an electromagnetically controlled coupling, a linkage for releasing the film, and after the released position has been reached, to disconnect the driving power from the linkage by means of the coupling, (2) to couple the driving power to the film-winding mechanism, but at the completion of the winding of one picture length of the film again to actuate the coupling to interrupt the winding, whereupon (3) the coupling again couples the driving power to the linkage and brings it back to the starting position wherein the film is pressed flat in the gate and at the completion of this step the driving members are automatically switched off and come to rest. As shown, the camera has a housing 62 carrying the lens 63, and having a partition 66 in which a film gate is formed. A cassette 21 guided to move only in the direction of the optical axis has chambers for film rolls 69, 70, the film 52 passing over a felt support 55. Spring means 68 press the cassette so that the film is. pressed against a glass plate 67. A motor 1 drives a gear-wheel 5 which is connected to a coupling 6. This coupling (see Group XXIV) is controlled by a shaft 7 to connect gear-wheel 5 to either of two co-axial gear-wheels 8, 9. In an intermediate position of shaft 7 gear-wheel 5 turns freely. Shaft 7 is caused to bear against a spring-urged core of an electromagnet 22 by a spring 24 connected to shaft 7 and also to a shaft 25, movable laterally against a spring 29 by an electromagnet 26. Gearwheel 8 is fast with a shaft 100 carrying a cam 11 and rollers 16, 17 with peripheral recesses 18, 19. These rollers engage contacts (not shown) which operate when they engage grooves 18, 19. After an exposure, the film-winding mechanism is started by an electrical impulse which may be provided by pressing a button 418 on the camera, or, where the camera is used for photographing X-ray images on a fluorescent screen, the X-ray apparatus may supply the impulse.' The impulse starts motor 1 and energizes electromagnet 22, withdrawing its core. Spring 24 urges shaft 7 against the core, in this position connecting gear-wheel 8 to gear-wheel 5, so driving shaft 100. A contact associated with roller 16 closes supplying current to the apparatus when the starting impulse has ended. Cam 11 has a follower roller 30 on a member 31 pivoted at 32 to the housing, and connected by a link 34 to a lever 35 pivoted to the housing at 37. Member 31 and lever 35 are fast with semi-circular rods 33, 36 whose flat faces face the cassette. Cam 11 rocks the lever system, turning rods 33, 36 so that the cassette is pushed away from plate 67. At the end of this movement, roller 30 drops into a recess 14 on cam 11 and contacts associated with roller 17 close, energizing electromagnet 26. This attracts shaft 25, and, through action of spring 24, moves shaft 7 away from the core of electromagnet 22,. thus uncoupling gear-wheel 5 from gear-wheel 8 and coupling it to gear-wheel 9, which is in mesh with a gear-wheel 20 on the film-winding shaft. The length of the film feed is controlled by a friction roller 41 in contact with the film. The surface of roller 41 may be knurled, and the film is pressed against it by a roller 72 mounted in the cassette 21 and spring-urged outwards through a slot in the felt support 55. Roller 41 is fast with a switch roller 42 having a groove 40 into which an arm 43 drops, opening contacts 415. An arm 48 is pivoted to the housing at 47 and is rocked alternately by a pin 49 on link 34 and a pin 44 on roller 42, operating contacts 414. Contacts 414, 415 are in parallel in the energizing circuit of electromagnet 26. Initially contacts 414 are closed. When the film wind begins, arm 43 is moved out of groove 40, closing contacts 415. Pin 44 rocks arm 48, opening contacts 414. Thus, when arm 43 drops into groove 40 again, contacts 415 open and break the circuit to electromagnet 26. Shafts 25, 7 return to their former positions, disconnecting gear-wheel 9 and re-connecting gear-wheel 8 to the gear-wheel 5. Shaft 100 again begins to rotate, and by action of cam 11 the film is again pressed against plate 67. The pin 49, during this movement, rocks lever 48 back to its previous position so that contacts 414 close. When the parts regain their starting position, contacts associated with roller 16 open, breaking the circuit to electromagnet, 22 and to motor 1. Shaft 7 moves to its intermediate position so that further movement of motor 1, due to its inertia, does not drive either of gear-wheels 8 or 9. The camera is ready for another exposure. Signal lamps such as 412 may be connected in circuit, so that a white light indicates the duration of the film feed and a red light indicates that there is no more film in the camera. Modifications are described in which the motor is controlled by a single electromagnet; in which two motors are alternately energized to effect movement of the cassette and winding of the film; and in which the cassette movement is effected directly by means of an electromagnet and the film wind is effected by a motor. Relays may be included in the circuit to ensure completion of the film wind when the starting impulse ends before the film wind.