Patent GB-276387-A (GB)
Title: Improvements in or relating to selecting mechanism for typeprinting telegraphy and other purposes
IPC: H04L15/34
Filed: 1924-11-17
Abstract: 276,387. Berryman, T. J. Feb. 26, 1926. Addition to 249,177. Type-printing telegraphs. - The apparatus described in the parent Specification is modified to adapt it for translating received signals based on a five-unit or a similar code. Fig. 1 shows a developed plan of a translating cylinder 1 provided with guide channels similar to those of Fig. 1 of the parent Specification but modified to correspond to the five-unit code. This cylinder is moved axially five steps, i.e. from the line O to the line V, for each character, and is positioned rotarily at each step by the engagement of the pin 2 or the pin 3 with the channel beneath it according as the corresponding impulse is - or +. The pin 2 is normally in engagement with its channel and is replaced by the pin 3 by a magnet energized only on receipt of a + impulse. Fig. 2 shows a modification of the cylinder for use with a receiving arrangement shown in Fig. 6, and adapted to prevent axial movement of the cylinder until the first + impulse of a signal combination is received. The tongue 41 of the neutral polarized line relay 40 closes a contact at 48 or 49 according as the received impulse is + or -. The contact 48 is in a circuit from battery 54 through a magnet 44 controlling the escapement mechanism 46 for moving the cylinder 1 axially and the magnet 47 for raising the pin 2 and lowering the pin 3. The contact 49 is in a similar circuit in which the magnet 47 is replaced by a series resistance 53 and a switch 52, and this switch is held open by a pin 56 on the shaft 21 of the cylinder 1 until the shaft is moved to the left upon receipt of the first + impulse. Fig. 7 shows an arrangement suitable for use with a cylinder 1 provided with axially-extending ribs co-operating with the pins 2, 3 to release it for rotation in one direction. On receipt of a + impulse the tongue of the neutral polarized line relay 70 closes the circuit of a magnet 79 corresponding to the magnet 47, Fig. 6, and on receipt of a - impulse it closes a contact preparing the circuit of a magnet 75 corresponding to the magnet 44, Fig. 6. The latter circuit includes a switch 80 which is held open by a pin 56a until this pin is moved by mechanism operated by the magnet 79 upon receipt of the first + impulse. In a modification the relay 70 is eliminated, the line impulses pass through the magnets 79, 75 in series, and a switch in a shunt across the magnet 75 is opened upon receipt of the first + impulse. In a further modification, the magnets 79, 75 are polarized to respond to + and - impulses respectively and are connected in parallel to receive the line impulses, and a switch in the circuit of the magnet 75 is closed upon receipt of the first + impulse. Fig. 10 shows mechanism for effecting a shift from letters to figures or vice versa. The shaft 21<a> of the transmitting cylinder 21 and type-drum 27 carries a cam 90 co-operating with the stepped end 91<a> of a lever 91 controlled by a spring 105, and the other end of the lever is pivoted to a rod 92 supported to slide over a. stop 115. The rod 92 carries projections 93, 94 adapted to actuate a rocker 95 carrying on leaf springs the platen 96 and tape guide 97. On receipt of a letter-blank signal the shaft 21a moves to the left to the position shown, and upon the subsequent energizing of the printing magnet 102 the rod 92 is actuated by a pin 103 on the hammer 101 causing the projection 93 to move the rocker 95 to the left and with it the platen and tape guide. On receipt of a figure-blank signal the shaft 21<a> moves further to the left and upon the subsequent energizing of magnet 102 the projection 94 returns the rocker to its former position. A device 100 retains the rocker in either position, and a stop 123 prevents movement of the hammer to printing position. On receipt of any other signal the shaft 21<a> moves still further to the left, beyond the end 91<a> of the lever 91, and the rod 92 is moved by the spring 105 clear of the pin 103, thus enabling the hammer to move to printing position upon energization of the magnet 102.