Patent GB-795318-A (GB)
Title: Improvements in or relating to start-stop teleprinter receivers
IPC: H04L17/18
Filed: 1956-02-06
Abstract: 795,318. Printing-telegraph receivers. SIEMENS & HALSKE AKT.-GES. Feb. 6, 1956 [Feb. 5, 1955], No. 3569/56. Class 40 (3). A start-stop printing-telegraph receiver including a storage device comprising a plurality of storage members each capable of storing one character and in which the received signals are stored before being passed on to the printing mechanism incorporates a locking member retaining the signals in the storage device and operating to release them in dependence on the completion of predetermined operations in the receiver. For example, the stored signal following the carriage-release or line-shift operations, which require relatively large periods of time for their operation, is delayed before it is applied to the selecting mechanism controlling the printer. In the arrangement shown in Fig. 1, the blade portion 3a of the armature 3 operated by the receiving magnet 1 controls the movement of pivoted levers 5 under the action of their springs 7 when their arms 5a engage the corresponding sequentially arranged recesses in cam members 8 mounted on the receiver shaft 9. If the armature 3 is attracted in response to the received impulse, the corresponding arm 5 is allowed to move counterclockwise by the recess so that the arm 5c moves inwardly the corresponding storage pin 11 ... 15 in the stirrup 10 rotatably mounted on the shaft 16. When the fifth impulse has been received, a latch 18 rocked by its arm 18a engaged by a cam 17 on the shaft 9 allows the stirrup 10 to be rotated by sleeve 36 and clutch 37. As shown, the second stirrup 20 with its pins 21 ... 25 selectively set by the preceding signal has been moved to the position in which the pins are about to co-operate with the sloping surfaces 31a ... 35a of selector members 31 ... 35 controlling the character or function selection and printing operation under control of the printer shaft 30. The rotation of the printer shaft is controlled by a latch lever 27 which can be rocked by the engagement of the stirrup 20 (or 10) with its arm 27a provided the shaft 30 is in its rest position with a recess in the cam 30b, opposite the extension 27b. The movement of the stirrup 10 (or 20) to operate the selecting members 31 ... 35 is additionally controlled during the carriage return operation by an arm 39 actuated by the carriage and which is retained in its left-hand position in which it engages the arm 27c to prevent the movement of the latch lever 27 until the carriage has returned to its starting position. After the pins 11 ... 15 or 21 ... 25 have set the members 31 ... 35 they are restored to their normal positions during the clockwise rotation of the stirrup 10 or 20 by a stationary cam 38. The rotational speed of the shaft 36 is considerably greater than that of shaft 9, or of shaft 30, and the period during which a stirrup, 10 or 20, moves through half a revolution from its storage position to its operating position, or vice versa, is arranged to be approximately 40 ms. when the signalling speed is 50 bauds and the time allowed for reception of a complete signal is 130 ms. In a modified signal receiving and storage arrangement, Fig. 3, the armature 43 operated by the receiving magnet 1 cooperates with a three-armed lever 45 having an arm 45c engaging spaced recesses of a cam 48 and an arm 45a with a lateral extension 45b associated with the ends of levers 49 carried on arms 51 biased by springs 52. The central portions of lever 49 are engaged by sequentially disposed humps on separate cams 54, and if the magnet 1 is energized the lever 45 is rocked so that the lever 49 is not restrained at its upper end and rocks freely about its storage pin 55 mounted in the stirrup 57. If the magnet 1 is not energized, the lever 45 is latched against movement so that the upper end of the lever 49 is blocked by the extension 45b and the movement applied by the associated humped cam 54 moves the lower end of the lever 49 to depress the corresponding storage pin 55. The storage pins may be parallel to each other along a radial line of a stirrup member which is rotated about an axis parallel to the pins, Fig. 4 (not shown). In an electrical storage arrangement, Figs. 5 and 7, the impulses received by the relay ER are applied by its contact er and sequentially operated contacts AK1 ... AK5 to capacitors C1 ... C5 which through contacts EK1 ... EK5 simultaneously closed after the signal has been received, selectively operate relays S1 ... S5, the armatures sl ... s5 correspondingly operating selector magnets D1 ... D5 and the printing release magnet DM when the contacts u have been closed. A contact HK1 closed at the beginning of the rotation of the receiver shaft energizes a relay H which at contact h allows a capacitor C7 to be positively charged. The contacts HK1 are opened after the impulses have been received, relay H releases, and at the released contact h the relay U is operated when the contacts HK2 are closed by the printer shaft in its rest or normal position. In response to the line-shift signal, the contacts t1 ... t5 of the relays T1 ... T5, arranged in series with the relays S1 ... S5, close a circuit to charge a capacitor C6 in parallel with the relay H so that its release is delayed after the contacts HK1 have opened with consequent delay in the operation of relay U and the resulting transfer of the signal which follows the line shift, and is stored on the armatures s1 ... s5 of relays S1 ... S5, to the selector relays D1 ... D5 and relay DM controlling the release of the printer shaft. The extended period allowed for the return of the carriage permits this function to be performed efficiently, e.g. without overheating, by an electric motor.