Patent GB-722512-A (GB)
Title: Improvements in or relating to teleprinting apparatus
Inventor: SMITH ERNEST WILLIAM
IPC: H04L12/06
Filed: 1952-06-20
Abstract: 722,512. Printing-telegraph transmitters. NATIONAL RESEARCH DEVELOPMENT CORPORATION. June 20, 1952 [June 26, 1951], No. 15188/51. Class 40 (3). In a telegraph arrangement for transmitting a fixed message, for example, as a prefix to a normal telegraph message, the code combinations representing the individual signals are determined by change-over switch members controlled by a series of relays, each of which has a number of windings which are interconnected to provide a number of actuating circuits giving combinations of signal elements corresponding to the characters. The fixed message is set up by connecting sockets 27, associated with contacts of a distributer, to sockets 28 representing various letters A ... Z, and functions, such as line feed, carriagereturn, letter-shift, &c., such terminals being connected through windings on one or more of the relays 20 ... 24 to provide selective actuation of the switches 15 ... 19 according to the character to be transmitted. The voltages at the contacts of the switch members are transmitted from the segments 8 ... 12 of a distributer 6 which makes one revolution during the single step movement of the arm 29 of the distributer 25. A switch member 48 connects + 50 v. to the operating circuit of the windings, a second switch member 50 completes a locking circuit for such relays 21 ... 24 as are operated, and a third switch member transfers the line circuit at 4, 5 to the normal message transmitter at the end of the cycle of the distributer 25. A counter mechanism and circuit comprises arms 32, 33, 34 connected to units, tens and hundreds and moving over contacts 0 ... 9 connected to the letters in the lower case corresponding to those numerals so that the latter are transmitted after prefixing the figure-shift signal. The units arm 32 is moved one step at each revolution of the distributer arm 29. The mechanical operation of the counter is effected by a crank 80 oscillating an arm 79 carrying pawls 83, 84, 85 associated with driver drums 73, 72, 71 connected to contact drums 76, 75, 74 for units, tens and hundreds respectively. Each oscillation of the arm 79 causes pawl 83 to move the drum 73 through one step and after ten steps a notch 94 allows pawl 84 to engage teeth on the left-hand side of the drum 72 which is advanced one step. After the drum 72 has been rotated through ten steps, the pawl 85 falls into a notch 94 in the right-hand portion of drum 72 and is able to move the driver drum 71 through one step. The contact drums 74, 75, 76 carry contacts 92, 93 engaging fixed pairs of contacts connected to the sockets representing the numerals 0 ... 9. The shaft 38 of the auxiliary transmitter is driven from the main shaft 36 of the teleprinter motor by a magnetic clutch comprising a soft iron shell 35, a winding 37 energized through slip-rings 39 and a soft iron plate 40 slidable on dowel pins 41 carried by a collar 42 on the driven shaft 38, the plate 40 being pushed away from the shell 35 by a helical spring when the windings 37 are not energized.