Patent GB-791245-A (GB)
Title: Improvements in or relating to keyboard perforators for perforating teleprinter tapes
IPC: H04L17/08
Filed: 1955-06-06
Abstract: 791,245. Keyboard perforators. SIEMENS & HALSKE AKT.-GES. June 6, 1955 [June 4, 1954], No. 16262/55. Class 31 (2). In a keyboard perforator for teleprinter tapes, for operating with a multi-unit telegraph code, having two or more type groups and single-type keys, a driving shaft for the movement of a punching device and the feed movement of the tape is arranged to operate on the start-stop principle and to be released for one revolution on actuation of any key, and renders possible during the single revolution the successive punching of the type group shift signal associated with the depressed key and of the other teleprinter signal corresponding to the depressed key. In the machine shown, the four key levers 1 to 4 are operatively connected to five selector bars associated with a shift bar 5, the latter being coupled to .a slidable transmission bar 6 provided with an extension 6a while each selector bar engages with a transmission member 7 which is connected to a punch control member 9 by means of a spring. Each of five punches 8 is adapted, according to the position of. its associated control member 9, either to perforate a tape placed above the punches or to remain at rest. The punches are operable by a reciprocable member 10 coupled with the drive. On depression of one of the keys, a shaft 15 is coupled to the drive for one complete revolution and effects in the course of each half-revolution a movement of the punching member 10 and immediately afterwards a forward feed movement of the perforated tape. Mounted on the shaft 15 is a cam 15a which is adapted to control pivotallymounted spring-influenced levers 16, 17 associated with the letter-to-numeral change and numeral-to-letter change respectively. Pivotally-mounted spring-influenced pawls 21, 24 are mounted respectively on arms 16a, 17a of the levers 16, 17. The levers 16, 17 also have arms 16b, 17b respectively which are operatively connected to a pivotally-mounted bell-crank lever 28 having a resilient lever 29 connected thereto. Extensions 16c, 17c, Fig. 8, of the levers 16, 17 control a pawl 33 associated with an extension 31a of a pivotally-mounted spring-influenced lever 31 provided with a pawl 36 associated with a ratchet-wheel. An extension 16d of the lever 16 is adapted to engage an extension 9b of the central control member 9. A locking lever 30 locks the five members 7 until the end of the second punching operation during each revolution of the shaft 15. In operation, if the last key to be depressed was a key of the numeral group, and a key of the letter group, e.g. the key connected to key lever 2 is then depressed, the shift bar 5 is moved to the right into the position shown in Figs. 1 and 2. The lever 16 can only rock to a small extent on leaving the cam 15a since the extension 16a of the lever 16 bears on the extension 6a of the transmission bar 6. On the other hand, the pawl 24 on the lever 17 is rocked in a counterclockwise direction by the extension 6a and the lever 17 follows the cam 15a into the position shown in Fig. 2 and also presses the lever 28 and connected resilient lever 29 against the extensions 9b of the punch control members 9. The five holes corresponding to the numeral-toletter change are accordingly first punched in the perforated tape. After the punching of the numeral-to-letter change signal, both levers 16, 17 are pivoted in the clockwise direction so that the pawl 24 is returned to its inoperative position and lies on the extension 6a while the lever 16 assumes a position with its arm 16a directly over the extension 6a. Accordingly, when a key of the letter group is thereafter actuated, the shift bar 5 remains in the same position and neither of the members 16, 17 can follow the cam 15a. Towards the end of the first half of the revolution of the cam-shaft 15, the tape is fed forwardly by means of the pawl 36 and associated ratchet-wheel. During the second half-revolution of the cam-shaft, the teleprinter signal corresponding to the depressed key is punched and towards the end of the second half of the revolution of the cam-shaft, the tape is again fed forward stepwise. When after a key of the letter group has been actuated one or more times, a key of the numeral group, e.g. the key connected to the key lever 1 is depressed, the shift bar 5 is moved to the left as shown in Figs. 6 and 7. The member 17 can rock only to a small extent, but the pawl 21 is rocked in the clockwise direction into the position shown in Fig. 6 by the extension 6a and the member 16 follows the cam 15a into the position shown in this Figure and presses the lever 28 and connected lever 29 against the extensions 9b of the punch control members 9. The central punch-control member 9<SP>1</SP> is thus forced to the left by the extension 16d against the action of the lever 29 into the non-punching position. As a result, the perforations of the first, second, fourth and fifth rows of perforations, corresponding to the letter-to-numeral change, are first punched in the perforated tape. After the punching of the letter-to-numeral change signal, the levers 16, 17 are again rocked in the clockwise direction to such an extent that the pawl 21 is freed from the extension 6a. The levers 16, 17 are thereafter turned back somewhat so that the pawl 21 rests on the extension 6a as does the extension 17a of the lever 17. The teleprinter signal associated with the depressed key is punched during the first half of revolution of the cam-shaft 15. The following perforated-tape feed is suppressed so that in the second half of the revolution of the cam-shaft, the same teleprinter signal is again punched at the same point of the perforated tape.