Patent GB-766004-A (GB)
Title: Improvements in or relating to facsimile receivers
Inventor: FOLL JOHN VICTOR
IPC: H04N1/36
Filed: 1953-08-27
Abstract: 766,004. Copying-telegraph receivers. MUIRHEAD & CO., Ltd. Aug. 18, 1954 [Aug. 27, 1953], No. 23710/53. Class 40 (3). A facsimile receiver incorporates a recording drum sufficiently long to enable a plurality of pictures to be recorded and includes automatic means for starting and stopping the receiver at the beginning and end respectively of each picture so that a number of pictures can be recorded in succession on the drum. The drum 1 mounted in tapered bearings 3 is driven from a plate 5 on a shaft 4 driven from a gearwheel 10 through a dog clutch 22, the gear-wheel 10 being driven from a motor through speed-reducing gears. A clutch 22 operated by a solenoid S1 arrests the shaft in a fixed position. A cam 20 on the shaft 4 operates a bell-crank 18 carrying a pivoted pawl 16 normally held out of engagement with a ratchet 15 on the threaded shaft 14 engaging a nut on the carriage 12 carrying the recording head 11. A masking member 24 operated by an electromagnet S2 allows the pawl 16 to engage the ratchet 15 so that the screw 14 is rotated to traverse the carriage 12. A shutter mounted on the top of the casing 2 and associated with the head 11 is connected by a linkage to the member 24 operated by the solenoid S2. When a picture is to be recorded, the received carrier is amplified at 37, detected at 38 and via a R.C. circuit of time period 2 secs. operates a relay RLA/1 in the anode circuit of a valve 39. At contact RLA1 selector magnet RLC3 is operated so that the arms RLC1, RLC2 of a selector are moved to contact 2 to operate clutch solenoid S1 so that the drum is rotated. When the phasing signal is received, relay RLB/1 operates and at contact RLB1 causes the arms RLC1, RLC2 to move to position 3 and then to position 4 in which the clutch solenoid S1 is de-energized and the traverse solenoid S2 is operated. If the transmitter is not switched off at the end of the picture, switch SW2 is opened by cam 40 on the movement of the carriage and the arms RLC1, RLC2 are stepped to position 5. When transmission ceases, relay RLA/1 releases and the arms step to position 1 in which the clutch solenoid is again energized and S2 is released, and the receiver is ready for a further transmission. For the transmission of the second picture contacts SW1 are closed and the selector arms remain in position 3 until the carrier is switched off when the release of relay RLA/1 causes the arms to step round to position 1. If the carrier is not switched off at the end of the transmission of the second picture, switch SW3 is opened by the cam 40 and the arms RLC1, RLC2 are stepped to position 1. In a modification, Figs. 5, 6 (not shown), the carriage 12 carries two switch members operated by a shaped guide member fixed to the frame of the machine, the switches being operated conjointly in association with transmission and phase relays corresponding to relays RLA/1, RLB/1, Fig. 4, to control three or more successive reproductions. In a simplified arrangement, Fig. 7 (not shown), the traversing solenoid S2 is energized when the phasing relay is operated and the latter is held energized by an auxiliary winding in series with a holding contact and the contact of the relay RLA/1. In a further modification, Fig. 8, the operation of the contact RLA1 prepares the circuit of the solenoid S2 which operates when contact RLB2 of the phasing relay closes. The solenoid S2 has a contact T1 which holds S1 de-energized when contact RLB1 of the phasing relay closes and a second contact T2 which maintains S2 energized when contact RLB2 opens.