Patent GB-737149-A (GB)
Title: Apparatus for transmitting signals recorded on a control form or tape
IPC: H04L17/12
Filed: 1953-08-14
Abstract: 737,149. Printing-telegraph transmitters. TELETYPE CORPORATION. Aug. 14, 1953 [Sept. 13, 1952; Sept. 13, 1952], No. 22456/53. Class 40 (3). Apparatus for transmitting signals recorded on a control form or tape,by means of a transmitter controlled by a mechanism which successively senses the recorded signals which may include one, or a sequence of a particular recorded signal which it is not desired to transmit, such as the rub-out or deletion signal, comprises an auxiliary sensing device which responds to the particular signal before it is sensed by the main sensing device and actuates means for preventing the particular signal (or all except the first of the particular recorded signals) from being transmitted. The perforations 13 of the tape 12 are sensed for transmission by pins 67 on levers 62 operating pivoted rods 61 which selectively close contacts 56 connected to segments 47 ... 52 of a distributer 43 having an unconnected segment 46 to provide the start element and a segment 53 providing the stop element by its connection to ground through a rod 58 on which the levers 61 are mounted. The levers 62 are released to sense the perforations in the tape by a bail 21 which is rocked during each revolution of the shaft 31 and which also operates an arm 19 carrying a pawl 18 engaging a ratchet wheel 17 to step forward the tape. Shortly after the operation of the bail 21 a cam 88 on the shaft 31 rocks a lever 83 carrying an adjustable pin 81 so that through levers 76, 74 a pivoted frame 69 is rotated clockwise about a shaft 71 if a second set of pins 73 carried on an extension 72 of the frame 69 senses a complete row of perforations indicative of the rub-out or erase signal. The movement of the frame 69 moves a latching lever 91 so that a notch 92 is engaged by an extension 97 on a pivoted frame 98 carrying an actuating pin 100. When the frame 69 is rotated to its normal position, the frame 98 is moved to the right so that the pin 100 closes contacts 101 and the start impulse constituted by the interruption of current on the line 45 is not transmitted. The member 98 when moved to its operative position is latched by a second latch lever 93 having a notch 96 engaging the extension 97. The release of the latch 93 is controlled by a pivoted member 108 which is released for rotation by a pin 117 engaged by a lever 119 actuated by a cam 124 on the shaft 31 and which carries an arm 111 associated with a projection 112 on the frame 69. If the rub-out signal is followed by a signal having less than six perforations, the frame 69 returns to its normal position, as shown, and the member 108 is free to rotate when the lever 119 is rocked by the cam 124 and the actuating arm 109 depresses the latching levers 91, 93 so that the frame 98 is released to return to its normal position with contacts 101 opened. If the first rub-out signal had been followed by another similar signal, the frame 69 is again moved to its actuated position in which the projection 112 obstructs the arm 111 and the pivoted member 108 is unable to rotate and disengage the latches 91, 93. In a modification, Fig. 2 (not shown), the rotation of a member equivalent to the frame 69 closes the circuit of a magnet which locks up under the control of a timing cam on the shaft of the distributer and, in addition, operates a second contact in series with contacts controlled by a further cam on the shaft to connect ground to the transmission line so that a start impulse is not transmitted for a number of signals corresponding to the number of rub-out signals. Fig. 4 (not shown) comprises a further modification in which a single rub-out signal is transmitted, but subsequent signals of a series of such signals are suppressed.