Patent GB-630672-A (GB)
Title: Improvements in or relating to telegraphic transmitting apparatus
IPC: H04L12/06
Filed: 1945-07-25
Abstract: 630,672. Telegraph transmitters. TELETYPE CORPORATION. July 25, 1945, No. 19060. Convention date, July 25, 1944. [Class 40 (iii)] Telegraph transmitting apparatus comprises a principal transmitter for transmitting messages recorded on a strip or tape, an auxiliary transmitter comprising a series of relays which are operated sequentially to govern the automatic transmission of predetermined station identification signals, means for initiating the operation of the series of relays to transmit the station identification signals and for suspending the operation of the principal transmitter during transmission of these signals, and means controlled by the auxiliary transmitter at the conclusion of its operation for automatically initiating operation of the principal transmitter. The transmitter, which may be generally similar to that described in Specification 562,551, comprises pivoted Y- shaped feeler levers 25 engaging simultaneously with recesses on a cam sleeve 24, and associated with sword members 33 pivoted on a frame 35 operated by a cam 38 on the shaft 13 of the principal transmitter. The rocking of the members 33 by their engagement with the upper or lower limbs of the levers 25 provides upward or downward movement of slidable members 41 which in their upper positions close their associated contacts 42. A distributer member comprises pivoted levers 44 engaging spirally arranged recesses on a cam sleeve 43 and operating five contact members 47 in sequence. A sixth contact member 83 is normally closed when the distributer shaft 14 is in its stop position and is opened momentarily during each revolution of the shaft 14. In the " off " position of the toggle switch 66, a circuit to line 72, 73 is completed over normally closed contacts 83 of the transmitting distributer, forming part of the automatic tape transmitter, conductor 82 and back contacts of relays 76, 79 effectively short-circuiting a relay 86. When the switch 66 is moved to its " on " position, the line circuit is completed over the relay 86, which at contact 91 de-energizes a slow-release relay 92 closing contact 93 and completing a circuit for a relay 96, which in turn energizes relay 99, closing at contact 101 an operating circuit for the magnet 21 controlling the rotation of the shaft 14. Conductors from the contact members 47 are carried by a cable 65 to the output side of an automatic transmitter 63 producing coded impulses corresponding to the station identification signal. The transmitter 63 which is the electrical equivalent of the station identifying arrangement shown in U.S.A. Specification 2,390,672 comprises a set of sequence relays and is somewhat similar to that described in U.S.A. Specification 2,317,955. A control relay 76 energized by a switch 30 which is operated manually or automatically provides locking circuits for relays 96, 99 since the circuit of relay 92 is intermittently completed at the contact 91 operated by relay 86. The opening of the normally closed contact 83 during each rotation of the shaft 14 temporarily releases relay 86 which at contact 89 provides an actuating circuit for producing the successive code signals from the chain of relays included in the transmitter 63. A relay 119 is invariably operated at the termination of the station identification message and remains operated during the transmission of the normal message by the tape transmitter. Relays 121 and 122 are arranged to be operated respectively according to whether a long or short fixed message is sent from the transmitter 63. If a short message is transmitted, the operation of relay 122 closes a circuit through the clutch relay 62 when contacts 53 are closed by a cam 48 on the distributer shaft 14. If, however, relay 121 is energized by a long message, relay 118 is operated over contact 20<1> and closes contact 125 over which switch relay 61 is operated, its circuit being completed at contact 60 of a relay 79 operated by the manual or automatic closing of a switch 40. Over contacts 123 of a switching relay 61 and the contacts 53 periodically closed by the distributer shaft 14, the clutch relay 62 is operated, and energizes the magnet 17 controlling the transmitter shaft 13. The magnet 21 controlling the distributer shaft is periodically energized over contacts 57 closed during each revolution of the shaft 13. The selective settings of the contacts 42 are effectively transferred over a cable 64 leading to the automatic transmitter and over the conductors of the output cable 65 to the distributer contacts 47 and thence to the line 72, 73. At the end of the telegraphic message the lever 151 engaged by unperforated tape opens the contact 152 in the circuit of the clutch magnet 16 and the transmitter shaft 13 ceases to rotate. When the tape is in the transmitting position and the toggle switch 66 is in the " off " position, the operation of switch 40 allows the station identification message to be transmitted. The operation of relay 79 effects the operation of the impulsing relay 86 by removal of the short circuit at contact 81 and the consequent release of relay 92 operates relays 96, 99. The distributer magnet 21 is energized over a circuit including contacts 101, 145 of relays 99, 79 respectively. At the end of the auxiliary message, the circuit of the switching relay 61 is not completed and the clutch relay 62 is not operated. If the switch 66 is in the " on " position and the transmitter 29 is against the punch block so that the tape is taut, the transmitter will not stop the tape and tear it, since the circuit of the transmitter clutch 21 will be open at contact 152. In a modification, Fig. 2 (not shown), the release of the distributer shaft is not controlled by the rotation of the transmitter shaft and a line-shorting relay, controlled by timing cams on the distributer shaft, provides a short circuit of the transmission line during the period of transition from the operation of the auxiliary transmitter to that of the principal transmitter to prevent the transmission of signal impulses during the rotation of the distributer shaft. A further modification, Fig. 3, includes an arrangement by which a taut tape during the concurrent preparation and transmission of a message does not immediately bring the auxiliary transmitter into operation. During the transmission of the main message, relay 119 of the auxiliary transmitter is energized and locked up over contact 50 of the magnet 99. Relay 406 operated by contact 139 of relay 119 provides an alternative circuit for relay 92 so that this relay is independent of relay 86 and is unable to control relay 99. If the tape becomes taut, contact 152 is opened, thereby breaking the circuit of the clutch magnet 16 of the transmitter and with the distributer shaft concurrently arrested and contacts 83, Fig. 1, closed the energization of the relay 86, with the transmitter at rest does not release relay 92 to actuate slowoperating relay 425 which would break the circuit of relay 99 thereby releasing the auxiliary transmitter 63. When the taut-tape condition has been removed, contact 152 closes and magnet 16 is again energized. Automatic control by end-of-message signals. A control arrangement 401, Figs. 3, 6, senses an end-of-message signal to terminate message transmission from the principal transmitter, and to initiate the transmission of a station identification signal from the auxiliary transmitter, transmission from the main transmitter being automatically resumed after the identification signals have been transmitted. During the normal signal transmission the operation of the relay 99 closes a circuit for the relay 76 which at contact 116 maintains an energizing circuit for relay 99 over released contact 418 of the relay 425. The end-ofmessage signals are effective to open contacts 407, 411 of the control arrangement 401. At contact 411 the circuit of the transmitter clutch magnet 16 is opened and the distributer shaft comes to rest and energizes relay 86 which opens contact 91. Contact 407 opens a second circuit of relay 92 which at its released contact 415 energizes slow-operating relay 425 opening the circuit of relay 99 which disconnects the magnet 16, breaks the locking circuit of relay 119, thus freeing the auxiliary transmitter for the succeeding station identification message, and opens the circuit of relay.76 which releases and breaks the circuit of the relay 425. As relay 86 is still energized, relay 92 remains released and relay 425 releases under control of relay 76 as that at contacts 93, 418 a circuit is again completed for relay 99 which initiates the operation of the distributer to transmit the station identification signals and apply pulses at contact 89 to the auxiliary transmitter 63. At the end of the operation of transmitter 63, relay 119 operates and locks up over contact 50 of relay 99. Message transmission is resumed from the principal transmitter until a further " end-of-message " signal is encountered. Control unit for end-of-message signal. The unit 401, Fig. 6, generally similar to a corresponding arrangement in Specification 562,551, responds to a signal comprising Figures, Carriage Return and Letters, in that order, to open contacts 407, 411. The Figures signal closes a circuit over a timing contact 448 and contacts 441d ... 445d to a relay 446 which locks up over released contact 458 of relay 459 which is de-energized at 461, 462, 463 when any of the three respective signals has been received. The Carriage return signal operates a slow-release relay 466 which opens the locking circuit of relay 446 and itself locks up over contact 475 of a slow-release relay 476. The Letters signal operates relay 476 over a circuit including operated contact 477 of relay 466. The operation of relay 476 opens the contacts 407, 411 and breaks the locking circuit of relay 466 which opens the circuit of relay 476 so that the contacts 407,