Patent GB-388785-A (GB)
Title: Improvements in or relating to keyboard controlled apparatus for telegraph systems
IPC: H04L17/06
Filed: 1931-09-03
Abstract: 388,785. Type-printing telegraphy. CREED & CO., Ltd. and GRIFFITH, R. G., Telegraph Works, Croydon. Sept. 3, 1931, No. 24737. [Class 40 (iii).] In a telegraph keyboard mechanism in which separate keys are allotted to the different characters and in which case-shift signals are employed for characters having the same code combination of impulses the normal depression of a character key operates means by which the appropriate shift signal is transmitted when a change of case with respect to that of the preceding character is involved. On the depression of a key involving a case-shift, the impulse combination of the character is mechanically stored until the case signal has been transmitted. Typical key levers 1, 2 .. co-operate with.permutation bars 3 .. 7 movable longitudinally in accordance with the signal combinations to rock members 11 .. 15, each of which carries a pair of parallel depending arms 18, 19, one of which is selectively lowered to an engaging position with respect to notches 20 in a set of combination bars 21 .. 25. The operation of any key lever moves a universal bar 9 actuating a rocking member 36 which raises a clutch detent 37 and releases a cam shaft 27 for half a revolution. A rejector cam (not shown) engages a rod 10 returning the detent 37 into the arresting position and restoring the bar 9 and operated key lever to their normal positions. On the shaft 27, cams 28 .. 32 with diametrically opposed projections engage and move outwardly both rods 18, 19. In accordance with the settings of the members 11 .. 15, the bars 21 .. 25 are simultaneously moved longitudinally to position selectively a further set of rocking members 41 .. 45, each having vertical arms 47, 48 engaging, when in the raised position, one of two rods 55, 56 fixed in a pivoted member 57 which through a lever 60 effects the impulse transmission from contacts 62, 63. On the release of the shaft 27, a depression in the cam 78 operates a lever 80 raising a locking bar 83 into engagement with one or the other of two notches on the lower edge of each of the bars 3 .. 8, and subsequently operates a lever 76 which, through links 72, 73, 75, releases the clutch 71 on the transmitting cam shaft. The start-stop impulses are sent by cams 65, 66 co-operating with rods 67, 68 mounted on a fixed member 69. When a key, corresponding to a character belonging to a case different from the preceding signal, is depressed, the bar 8 rocks the member 16 so that the cam 33 moves the rod 26 to release the cam shaft 84, when the selection is transferred to the rods 21 .. 25, but before cam 78 operates to release cam shaft 47. Cam 92.rocks levers 93, 94 so that the cam shaft 27 is arrested, and the case-shift signal is transmitted by the cams 87, 88 operating pins 89, 90 secured to the rods 67, 68. At the end of half a revolution the end of the lever 93 falls into the cam 92, releasing the cam shaft 27 with the cam 78 which subsequently releases the cam shaft 47 for the transmission of the impulse combination set up on the rods 21 .. 25 and transferred to the rocking members 41 .. 45.