GB320671A - Improvements in or relating to systems for the electrical transmission and reception of pictures, diagrams or other representations - Google Patents

Abstract

320,671. Fulton, O. July 20, 1928. Synchronous movements.-In a copying-telegraph using rotating transmitting and recording drums, the synchronizing and picture signals are applied to a receiving circuit containing an electromagnetic device 22, which, when energized by a synchronizing signal, releases a catch 24, previously holding the receiving-drum stationary, and engages a clutch b for coupling the receiving- drum to its drive, and means 3, 6, controlled by the rotation of the drum, maintain the clutch in engagement when the synchronizing signal ceases. When a point D at the beginning of a conducting- segment DE on the transmitting-drum, Fig. 2, arrives at the transmitting-stylus a current is transmitted which causes the closure of the contacts of the relay 22, Fig. 1. The catch 24, Fig. 4, is thus attracted and closes contacts 2 to energize the electromagnetic clutch b. Contacts 3 then close, through the movement of a cam 6, and a slot 25 in the recording-drum moves clear of the catch before the point E reaches the transmitting-stylus, when the relay contacts open. While the transmitting-stylus is opposite a point between E and the beginning A of the picture, cam jack 4 transfers the output of an amplifying valve 21 from the relay to recording-apparatus 23, and when the point A reaches the stylus, the picture starts. As the end C of the picture reaches the transmitting-stylus, the picture ceases, and as a point M between C and D reaches the stylus, the cam jack 4 transfers the output of the valve to the relay. Immediately afterwards, the contacts 3 are opened to release the clutch and the catch drops into its slot, where it remains until the above process is repeated on the arrival of the point D at the stylus. Alternatively, the segments CD, EA are of conducting material and DE is insulating, and the transmitter is arranged as described in Specification 320,673. The apparatus may be modified to operate with optical transmitting-apparatus. Specification 307,365 also is referred to and Specification 318,121 is referred to in the Provisional Specification.