GB1011358A - Improvements in keyboard transmitters for telegraph systems or the like - Google Patents

Abstract

1,011,358. Typewriters &c. BRITISH TELECOMMUNICATIONS RESEARCH Ltd. Dec. 11, 1963 [Sept. 11, 1962], No. 34667/62. Heading B6F. [Also in Division H4] The keyboard of a telegraph transmitter is detachable from the main frame and can be replaced by a keyboard of different character layout. In addition, a cross-connecting unit, which produces a coded, output corresponding to depression of a key, can be replaced by another unit to provide a different corresponding coded output. The keyboard unit 1 is clipped to the frame by springs 3, but the space bar is not detachable. Depression of a key rocks an associated bar 7 about pivot 8 whereby lever 41 moves clockwise about pivot 40; lever 41 is common to all the bars 7 and moves pawl 42 upwards to disengage latch 36 from arm 34. Armature 27 and lever 30 now move anticlockwise, moving bar 32 to the right so that bar 7 is locked by bar 33. Movement of armature 27 operates a switch which starts a distributer. At the end of the distributer cycle the electromagnet is energized and latch 36 re-engages arm 35. Each bar 7 operates a corresponding switch which feeds a diode cross-connecting unit. This generates a code signal corresponding to the key depressed. If a key is pressed for a time longer than a transmitted character the character is not repeated since, on energization of the magnet at the end of the distributer cycle, the bar 32 is latched by 36. Depression of a key for too short a time has no adverse effect since the corresponding bar 7 is locked by bar 33 during the distributer cycle. Depression of more than one key at a time is prevented by a ballbearing and wedge arrangement 12, 13.