Patent GB-777416-A (GB)
Title: Teleprinters for radio-electric links
Inventor: COQUELET JULES
IPC: H01H51/32
Filed: 1955-09-06
Abstract: 777,416. Type-printing telegraphy. ATELIERS DE CONSTRUCTIONS ELECTRIQUES DE CHARLEROI. Sept. 6, 1955 [Dec. 13, 1954], No. 25526/55. Class 40 (3). In a radio printing-telegraph system in which the code signals are transmitted by two frequencies sent in succession and selected respectively from two groups of frequencies and in which the receiving arrangement comprises two selectors comprising vibratory reeds tuned to the frequencies of the group, a reed in a group selector after having been selected is restored to rest before that selector is again employed in order to prevent a faulty selection due to remanent vibration when the subsequent signal is received. In the system described in connection with Figs. 1a to 1d, two pairs of selectors represented by windings I, II and I<SP>1</SP>, II<SP>1</SP> are included and the successive signals are applied alternately to the two pairs of selectors I, II or I<SP>1</SP>, II<SP>1</SP> by a change-over relay arrangement permitting a delay between the successive operations of selectors I, II and I<SP>1</SP>, II<SP>1</SP>. The reception of a complete signal by either selector operates a relay RII controlling the printing operation. When a signal has been received by windings I<SP>1</SP>, II<SP>1</SP>, Fig. 1a, and relay RII has operated, relay RIV operates over actuated contact B2 and at contact B4, the first frequency of the subsequent signal is applied to winding I. A circuit is also completed for relay RIII which on operation allows the frequency forming the second part of the signal to be applied to winding II. Also relay RII releases so that the circuit of relays RIII, RIV is maintained over contact B<SP>11</SP>4. When the signal applied to windings I, II has been received, relay RII again operates and completes a circuit for the opposing winding of relay RIV which releases. Relay RIII remains energized over operated contacts B<SP>1</SP>3 and B2, but is released when relay RII is deenergized so that the relay arrangement is restored to the condition shown in Fig. 1a for the reception of the subsequent signal by windings P, II<SP>1</SP>. The received frequencies apply potentials to one or more of the grids g<SP>1</SP>, g<SP>2</SP>, g<SP>3</SP>, g<SP>7</SP> and to one or more of the grids g<SP>4</SP>, g<SP>5</SP>, g<SP>6</SP> of valves T1 ... T7. When a reed l1 of a group has been set into vibration, it closes a contact v connected to the grid of one or more of the thyratrons T1 ... T3 and T7, or T4 ... T6 associated with the two groups of frequencies. In the arrangement in which the reed is brought to rest by a damping device the operation of one or more of the thyratrons T1, T2, T3, T7 energizes a relay RI which at contact B1 actuates a damper magnet EI. The operation of one or more of the thyratrons T4 ... T6 energizes relay RII which at contact B<SP>1</SP>2 operates the damper magnet EII and at contact B<SP>11</SP>2 energizes the relay winding R controlling the printing operation. As shown in Fig. 3, the damping arrangement comprises a flanged member E, carrying damping pads, which is pivotally mounted on an axis a and is actuated by a magnet A, corresponding to the magnets EI, EII of Fig. 4. The contacts iI, iII in the circuits of the relays RI, RII are actuated by cams on the shaft of the receiver.