Patent GB-453596-A (GB)
Title: Improvements in or relating to the transmission of pictures
IPC: H04N5/222
Filed: 1935-01-14
Abstract: 453,596. Copying-telegraphy. GEFFCKEN, H., 9, K÷nig-Albert-Strasse, Naunhof, near Leipsic, and RICHTER, H., 3, Wiederitzscherstrasse, Leipsic, Germany. Jan. 14, 1935, No. 1281. Convention date, Jan. 12, 1934. [Class 40 (iii)] [See also Group XX] Apparatus for aerial reconnaisance comprises a camera 11, Fig. 2, through which film is drawn for exposure by an intermittently rotating gear 12 under the control of the operator, the film forming a loop F between the gear 12 and a continuously moving gear 13 which draws the exposed film into developing and fixing tanks and thence to a picture transmitter 25. According to the invention, the gear 12 rotates automatically when the loop F becomes so short as to be in danger of breaking. The loop carries a jockey roller 12a which lifts when the loop shortens to close a contact 12c which operates the gear 12. In order to prevent unnecessary consumption of film, each exposure is marked, as by a puncture 9, Fig. 1a in the film, and two counters record the number of exposures and the number of pictures transmitted. When the counters read the same, no pictures are contained in the loop from camera to transmitter and the two counters may operate a device for stopping the feeding of film. The punctures in the film may also be used to actuate feelers which cause a nozzle 15 to spray on developing solution, a brush 16 to spread it evenly and a nozzle 19 to spray fixing solution. The two gears 21, 21a may make contact through the punctures and so cut in the transmitter for picture signals while at other times the transmitter can be utilized for speech. In an alternative embodiment, the gears 12, 13 are each coupled to shafts 72, 75, Fig. 7b, carrying bevel gears 73, 76 acting on a planet wheel 79, so that the differential movement of the gears 73, 76 corresponding to the shortening of the film loop F to the breaking point, rotates the planet wheel 79 through a sufficient angle to close a contact 80 to rotate the gear 12 automatically. The gear 13 is also coupled to a disc 81, Figs. 8a, 8b, carrying pins 82 normally pressed down to the disc by springs 84. The planet wheel 79 is coupled to a disc 85, Figs. 8a, 8b, concentric with the disc 81 and carrying an electromagnet 86 mounted at one edge of a cut-away portion d of the disc 85. At each exposure the disc 85 moves intermittently in the direction 87 and between exposures moves uniformly in the direction 86. At each exposure the electromagnet 86 is energized to lift a pin 82 and the disc 85 rotates to move under the pin head 83 to maintain the pin lifted until it drops back at the cut-away portion alpha. Each lifted pin corresponds to one exposure and in rotating with the disc 81 actuates contacts, of which only one 89 is shown, controlling the operation of the nozzles 15, 19 and the picture transmitter. The pins also make electrical contact between the discs 85, 81 which are in series with the contact 80 so that the gear 12 is only automatically rotated if the length of film between the gear 12 and the transmitter contains an exposure. The scanning device comprises a light source 66, Fig. 6a, 6b, co-operating with a series of lenses 60a, apertures 60b, prisms 60c, and projectors 60d, the whole assembly rotating above the uniformly moving film F and co-operating with a cell 23. A synchronizing impulse is generated at the beginning of each line when the projector traverses the aperture 70, Fig. 6b. A light source 71 may be switched on to illuminate the cell 23 and render the picture transmitter idle. At the receiver, the picture is reconstituted by a similar scanning device 39, Fig. 3 on a film 40. A signal lamp 32 indicates when the transmitter is operating. Phasing is corrected by manually operating a wheel 45 rotating the scanning device 39 and is visually observed on a fluorescent screen 43 moving synchronously with the film and co-operating with that scanning projector which is 180‹ out of phase with the operative projector. The receiver may record on a double width of film so that synchronism is sufficient without phasing, Fig. 5a (not shown). The synchronizing impulse, being of constant intensity may be utilized as the normal blackening to check tone of the picture and detect fading. Specification 297,078, [Class 40 (iii)], is referred to.