Patent GB-380661-A (GB)
Title: Improvements in apparatus for the telegraphic transmission of graphic subjects
IPC: H04N1/12
Filed: 1931-12-05
Abstract: 380,661. Copying-telegraphy; synchronous movements. DELCHEF, G., 55, Square Marie Louise, Brussels. Dec. 5, 1931, No. 33808. Convention date, Dec. 5, 1930. [Class 40 (iii).] In an apparatus for the telegraphic transmission of pictures comprising a cylinder cooperating with a contact-carrying carriage, governed by a clockwork device and adapted to be displaced parallel to the generators of the cylinder, the contact member'is operative during the movement of the carriage in one direction only, and the cylinder is given a slight rotation on its axis upon the return of the .carriage to its initial position for the transmission of a subsequent line of the picture. The picture, which is formed with conducting and insulating portions, is traversed in a series of lines forming generators of a cylindrical conducting drum 5 by a contact mounted in a carriage 11 moved along guide rods 9, 10 by a cord 28 passing round a pulley 27 intermittently clutched to a motor. The carriage is returned to its initial position by a second pulley 28<2> under the action of a coiled spring 28<4>, and at the end of the return stroke, a pin 19 on the carriage engages a pivoted lever 20 carrying a pawl 22 which steps forward a toothed wheel on the shaft of the picturefeeding drum 5. The driving arrangements at the transmitting and receiving ends are each under the control of a device controlled chronometrically as shown in Fig. 3. A disc 48 on the shaft 50 of the chronometer is held in the rest position by a tooth 56 engaging a projection 57 on a pivoted lever 58. The apparatus is set into operation for transmission by the closure of a switch 16<1>, which, in the rest position of the disc 48, energizes, through contacts 62, an electromagnet 63 attracting the arm 58 and releasing the disc 48. At the same time, contacts 64, 65 close for the motor M a circuit which is subsequently maintained over a brush 70 and a conducting ring 49 formed on the disc 48. The shaft 50 drives gear wheels 52, 54 through intermediate gearing (not shown), and when an insulating segment 72 is rotated out of engagement with the wheel 52, a circuit is completed through a commutator 36 to an electromagnetic clutch 35 by which the pulley 27 is driven from the motor. M and a disc 42, on the shaft 30, is moved. longitudinally to close, at contacts 43, 44 the circuit from the transmitting drum 5 to the lines 15, 16, and to the receiving drum 5<1>. When the insulating segment 72 breaks the circuit of the clutch 35 contacts 43, 44 open, the pulley 27 is released from the motor M, and the carriage 11 is returned to its initial position under the action of the spring-controlled pulley 28<2>. The disc 48 is brought to rest at the end of a revolution by the tooth 56, and the insulating segment 67 opens the circuit of the motor M. At the end of the longitudinal movement of the carriage 11 at each station with the switch 16<1> open each disc 48 is brought to rest, and when the switch 16<1> is again closed release magnets 63 energize over contacts 62 at the two stations for the transmission and reception of the next line of the picture. If the chronometers at the transmitting and receiving stations are in accurate synchronism the switch 16<1> may be maintained closed for the transmission of several lines, the gear wheels 52, 54 making several revolutions for one revolution of the disc 48. If the synchronism is approximate, the switch is operated at the end of the transmission of each line to effect the simultaneous operation of the magnets 63 at the two stations.