Patent GB-573121-A (GB)
Title: Improvements in or relating to telegraph apparatus
IPC: H04L15/18
Filed: 1943-11-29
Abstract: 573,121. Code telegraphy. CABLE & WIRELESS, Ltd., and WARBURTON, F. Nov. 29, 1943, No. 19910. [Class 40 (iii)] A high-speed automatic transmitter is operable either by a strip, Fig. 3A, perforated in accordance with the Wheatstone code in which dots 1, 2 and dashes 49, 50 occupy different lengths or by a strip, Fig. 3C, perforated in accordance with cable code in which dots 204 and dashes 205 occupy the same length, the transmission in each case being in Wheatstone code and means being provided to suspend the feed of the cable-code strip during the extra time required to transmit a Wheatstone dash. High speed is obtained by operating the signal contacts by power from a motor-driven shaft. Operation by Wheatstone-code strip. The design of the mechanism is such that the Wheatstone-code strip must be fed to the sprocket 9 in reversed sense as shown in Fig. 3B. The sprocket 9 is fed in two steps for one centre feed by staggered ratchets 10, 11 operated successively by pawls 13, 14 suspended by links 24, 25 and actuated by eccentrics 15, 16 arranged 180 degrees out of phase on a power-driven shaft 17. The strip is thus advanced one centre feed during each cycle of rotation of shaft 17, a dot being represented by a marking signal occupying one half-cycle followed by a spacing signal of similar duration whilst a dash comprises a marking signal occupying three half-cycles followed by a spacing signal of one half-cycle. Peckers 3, 4 are mounted on actuating members 81, 84 engaged by lugs 95, 96 on a T-shaped member 94 pivoted to a bellcrank lever 92 controlled by a spring 90 which urges the peckers into contact with the strip. After exploring the strip, the peckers are restored by a lever 100 actuated by a third eccentric 97 on the power-driven shaft 17. A fourth eccentric 116 on shaft 17 actuates the line contacts 5, 6 through a lever 120 pivoted at 85 and carrying a pin 121 on which are mounted dash, dot and spacing levers 122, 123, 124. When a dot 1, 2 is encountered by the peckers, both rise to their full extent and arm 105 on actuating member 84, through lever 106, 107, removes a stop from tail 129 of dot lever 123 so that when pin 121 swings to the left shoulder 133 on lever 123 engages arm 127 to rock contact-actuating member 125. Member 125 acts on a second contact-actuating member 152 to close marking contacts 5 and open spacing contacts 6. Member 125 carries pins 150, 154 engaging arcuate surfaces centred on pivot 126 to hold the contacts positively in each position. When pin 121 swings to the right, spacing lever 124 engages arm 127 to terminate the dot. When the peckers encounter the first element 49 of a dash, pecker 3 only rises to its full extent and the lower arm of T -member 94 is tilted to the left causing lever 113, 114 to remove a stop from the tail 128 of the dash lever 122. Shoulder 132 on this lever operates contacts 5, 6 as before and a lug 171 on the end of the lever operates latch levers 182, 174 to prevent spacing lever 124 from terminating the dash at the end of the first half-cycle. Dash lever 122 also unlocks three-armed lever 191 which at its arm 195 renders the peckers inoperative to reach the strip during the second cycle of the dash. When pin 121 moves to the left during this second cycle levers 182, 174 are unlocked and spacing lever 124 is then able to terminate the dash. Operation by cable-code strip. Button 203 is turned through 90 degrees causing cam 163 to raise lever 165 and thereby remove lug 170 from the path of lever 39. When a dot 204, Fig. 3c, is encountered the operation is substantially the same as that already described, the tilting of arm 94 to the right being without effect. When a dash 205 is encountered, dash lever 122 operates as already described but arm 198 of lever 191 causes lever 39 to move into the path of a projection 42 on pawl 13 whereby pawls 13, 14 are rendered inoperative to advance ratchets 10, 11 during the second cycle of the dash.