Patent GB-850175-A (GB)
Title: Tape feed-out devices for telegraph apparatus
IPC: H04L17/08
Filed: 1957-03-08
Abstract: 850,175. Printing telegraph receivers. AMERICAN CABLE & RADIO CORPORATION. March 8, 1957 (March 13, 1956], No. 7748/57. Class 40(3). In a tape feeding apparatus for a signal receiving and recording arrangement comprising means responsive to the receipt of each code signal combination for feeding the tape a predetermined amount by feed means operated by a shaft which is normally arrested by stop means after each revolution, means operated when a predetermined code signal has been received a specific number of times controls a timing device to permit a predetermined additional amount of the tape to be fed out of the recording arrangement by holding the stop means ineffective for a predetermined period. Towards the end of a revolution of the selector cam sleeve 5, a cam 5a engaging the end of the arm 4b of a pivoted lever I raises the other arm 4a against the action of a spring 4 so that a projection 3 trees a disc 3<SP>1</SP> to move under the action of a spring 7a and through clutch portions 7, 7<SP>1</SP> to connect bail cam 8 and punch cam 9, which actuates the tape feed, to the motor shaft 6. Normally the lever 1 is restored by the cam 5a so that the projection on the arm 4a separates the clutch members 7, 71 towards the end of a revolution of the cams 8, 9. To provide extended feed-out of the tape, the lever 1 is held against restoration during the period the armature 10 is held by the energization of its magnet 11. For the printing operation, as shown in Fig. 2, the type bar 12 pivoted at 12<SP>1</SP> and having a gear segment 13 meshing with a rack portion 14a on a pull bar 14 biased downwardly by a spring 15, is moved upwardly when the bar 14 engages aligned slots in selector levers 16 so that the projection 14c is engaged by the upwardly moved bail 17. The bent over portion 14b is slidably connected at 20 to the lower member of a contact pair 19 so that the contacts are closed when the bar 14 is selected. The bars 14 corresponding to the signals for carriage return and line-feed are provided with contact pairs, such as 19. At the end of a message a number, for example four, of line-feed signals are transmitted, and in the circuit arrangement, Fig. 3, the contacts 19, 19<SP>1</SP> respectively are closed by the line-feed and carriage return signals. On the receipt of a lineteed signal contacts 19 close. and a magnet S steps a switch Sl from its normal position and closes off normal contacts ON. If the message has not ended, the carriage-return signal follows, contacts 19<SP>1</SP> close and reset magnet R is operated to restore the switch S1 to its normal position. In response to four line-feed signals, the switch S1 is stepped to terminal 5 strapped to front contact 26 of relay K1 which is operated by the stop condition on the input line L. At contacts 25 the short circuit of a capacitor Cl is removed, and after a predetermined interval, e.g. 5 secs., the tube VT1 fires. At contact 26 positive potential is applied over the selector switch to the windings of relays K3, K4, K5 and to the anodes of tubes VT2, VT3. When VT1 fires, relay K3 operates and at contacts 29 short circuits the winding of the selector magnet 21 to simulate the start element and permit the selector shaft 6 to rotate to commence the additional tape feed out. Also the opened contact 30 allows the capacitor C2 to charge, and after a short interval tube VT2 fires and operates relay K4 which at contact 29 opens the shunt path of magnet 21 which reoperates. At contact 31 the short circuit of capacitor C3 is removed, and a circuit is also completed to the magnet 11 operating the lever 1, Fig. 1, so that tape feed-out is maintained and continues until the tube VT3 fires after an interval of, for example, 20 secs. When the tube VT3 fires, relay K5 operates and opens the circuit of the magnet 11 which releases lever 1 so that tape feed out is discontinued. At operated contact 34 a circuit is completed through contacts ON to the reset magnet R which restores the switch S1 to its normal position. When transmission is resumed the release of relay Kl by the start element releases K3, K4, K5 and extinguishes the tubes VT1, VT2, VT3. If transmission is resumed during the initial 5 second period before VT1 fires, the normal operation of the printing reperforator is resumed. If transmission recommences during the 20 second feed-out period, relay Kl releases, followed by relays K3, K4, K5 which remove the short circuit of the selector magnet and effect release of magnet 11 so that the lever 1 is actuated from the receiver cam shaft. If the requisite number of line feed signals is not received the tape feed-out may be initiated by the operation of a push-button PB operating relay K2 which opens a shunt path of capacitor Cl to start the timing cycle of 5 secs. and connects positive potential to relays K3, K4, K5 independently of the contact level L1 of switch S1. Specification 540,612 is referred to.