Patent GB-190504957-A (GB)
Title: Improvements in Printing Telegraph Systems.
Inventor: PAGE SYDNEY ELLIOTT
Filed: 1905-03-09
Granted: 1905-09-14
Abstract: 4957. Page, S. E., [Swift, F. J.]. March 9. Telegraphs. -Relates to printing-telegraphs in which the working electro-magnets at the distant station are selected by means of various combinations or permutations of currents transmitted through a single line-wire. In the apparatus described, each character is selected by means of a sequence of three currents. There are four varieties of currents from which the combination can be selected, namely positive, negative, an intermittent impulse consisting of a long impulse and a short impulse alternatively of which the long impulse is positive and the short one may be either positive or negative, and a similar intermittent impulse in which the long impulse is negative. The third current of a sequence may be of the same character as the first. Figs. 3, 4, and 5 are to be read together as a single Figure. Fig. 3 shows the apparatus at the transmitting-station, the line-wire 14, and part of the apparatus at the receiving- station ; Figs. 4 and 5 show the remainder of the apparatus at the receiving station. The battery 23 is shown supplying a local circuit at the transmitting-station through wires 29, 26. Transmission is effected by means of the keyboard instrument shown in Fig. 2. Whenever a key C is depressed, three projections H depress three of the twelve bails E, and three of the twelve pairs of contacts F, G are closed. At the same time, the universal bar K is depressed, and the contacts Q, R, Fig. 3, are closed. The twelve pairs of contacts F, G are arranged in four groups of three, as shown in Fig. 3. Group 1 serves to transmit positive currents from the battery S, group 2 transmits negative currents from the battery T, and groups 3, 4 transmit intermittent + and - currents respectively, each consisting of short and long impulses alternately, from the same batteries through make-and-break devices 11, 13. The contacts Q, R serve to close the circuit of the battery 23 through an electro-magnet a, the result of which is to bring into action successively the electromagnets b, c, d. The line-wire 14, which is normally connected to the wire 46, is consequently connected after a short interval to the wire 47, and finally to the wire 48. Assuming that the key which has been depressed has closed the contact 1<a> in group 1, 2<b> in group 2, and 3<a> in group 1, the currents set to line will be + - +, no intermittent currents being used for this particular signal. At the receiving-station, the line currents pass to earth thiough the four polarized relays e, f, g, h in series. The relays e, f closes the local circuits of the selecting-magnets j, k in response to + and - currents respectively, and the relays g, h open the normally-closed circuits of the selecting- magnets l, o (owing to the vibrations of their armatures) in response to intermittent + and - currents respectively. The effect of a received line current is consequently to connect the upper one of the two wires marked 69 in Fig. 3 with one or other of the four wires 69, 85, 85<a>, 85<b> according to the nature of the current received. The said upper wire is connected, as shown in Fig. 4, to the positive pole of the battery 23, and the negative pole of the battery is connected through the wires 69, 72, 69 to a point 71 which forms a common terminal for the windings of four "selectable" electro-magnets p, q, r, s. Each of these electromagnets has its two coils arranged in series with the coil 19 of an electro-magnet x, y, z, or z<1>, the circuit in the case of the electro-magnets p, x being shown in heavy lines. It follows therefore that a + line current effects the energization of the pair of electro-magnets p, x, a - line current energizes the pair q, y, and intermittent currents energize the pair r, z, or s, z<1> according to their sign. Each of the electro-magnets p, q, &c. closes nine of the contacts 16 in the circuits of the working electromagnets V, and each of the electro-magnets x, y, &c. closes five contacts 21. One of these contacts is situated in the circuit of a coil 20 arranged in a "holding" circuit 68, the result of which is that although the energization of the magnet p &c. is only temporary, and the contacts 16 open as soon as the line current ceases, the corresponding magnet x remains energized. The holding circuit 68 includes contacts76,77,Fig. 4, so that it is opened when the electro-magnet 75 is energized. In connexion with the selectable magnets p, q, r, s are four circuit-controlling magnets t, u, v, w, each of which controls four contacts. One of these contacts is normally open ; the other three are normally closed and are in the circuits of the other three electro-magnets. Consequently, only one of the electro-magnets t, u, v, w can be energized at one time. The magnet t is energized as the result of the closing of the extreme left-hand contact 21 of the electro-magnet x, the circuit including the normalty-closed contacts of the electro-magnets u, v, wand the contacts 76, 77 of the holding circuit 68. The above operations having been effected by a positive line current, it will be assumed that the second current of the sequence is negative. This current causes the momentary energization of the selectable electro-magnet q, and the permanent energization of the holding electro-magnet y in a similar manner to that already described. The magnet q operates nine pairs of contacts 16 for a moment. The closure of the contacts 21 of the magnet y closes its holding circuit but fails to energize the magnet u owing to the fact that the magnet t has been previously energized and its normally-closed contacts are open. Each of the circuits of the working magnets V, of which the wires 90, 69 are the common terminals in Fig. 5, includes three breaks or gaps, one being in the series 16, the second in one of the groups 21, and the third being one of the four normally-open contacts of the magnets t, u, v, w. By the + - sequence of currents so far described, two of the breaks in the circuit of the working magnet v<1> have been closed, these being one of the contacts 21 of the electro-magnet y, and the normally-open contact 17 cf the electro-magnet t. If, then, a + line current is sent as the third of the series, the electro-magnet p is again energized, closing nine of the contacts 16, including that one which was required to complete the circuit of the working electromagnet V<1>. This circuit, which terminates at 90, 69 in Fig. 5, includes, as shown in Fig. 4, the electro-magnet 92. The electro-magnet v<1> only serves to bring the desired character into position ; the actual printing is effected by the electro-magnet z, Fig. 4. The printing and the breaking of the holding circuits are brought about as follows: When the electro-magnet 92 is energized, the armature 95 breaks the circuit of the printing-magnets Z at 100, closes the circuit of the electro-magnets 75, 105 at 99, and closes an extra pair of contacts 101 in the holding circuit 68. In consequence of this last-mentioned closure, the electro-magnet 75, when energized, fails to break the holding circuit. The armature 106 being attracted, the circuit of the magnet 114 is closed, and the armature held down. When the finger is removed from the keylever, the circuit of the electro-magnet 92 is broken, owing to the de-energizing of the selectable electromagnet p. The holding circuit 68 is consequently broken, and the magnets 75, 105 are de-energized, but the armature 106 remains attracted. The circuit of the printing-magnet Z is consequently closed, and, in the act of printing, the magnet 114 is short-circuited at 120 and the armature 106 retracted, all the parts being then in the initial position. Reference is made to Specification No. 8890, A.D. 1901.