Patent GB-191125216-A (GB)
Title: Improvements in Automatic Telephone Systems.
Inventor: BETULANDER GOTTHILF ANSGARIUS
Filed: 1911-11-13
Granted: 1912-08-08
Abstract: 25,216. Betulander, G. A. Nov. 16,1910, [Convention date]. Automatic exchange systems; metering systems.- In a system of the kind in which the selectors are set by means of two co-operating magnets, current passing continuously through one magnet whilst the selecting-impulses pass through the other, the selectors are released by energizing the second magnet whilst the first is de-energized. The invention is described as applied to a system in which the group selectors are one-coordinate switches having no rotary hunting movement, the final selectors or connectors being two-coordinate switches of the type described in Specification 410/12. Construction of preliminary and group selectors. The wipers 1, 2, 3, 4 and test roller 6 are carried by a ratchet bar 41, sliding in the arms 7, 8 of the frame 9, and fed upwards by a pawl 16 on the armature of a magnet 12. The detent pawl 24 carried by the armature of a magnet 13 only engages the ratchet when the magnet is energized. The frame 9, carrying the magnets 12, 13, bar 41, and wipers, is mounted on pivots 33 on a disk 34 so that it can swing slightly to and from the disk, in order that the wipers may not touch the contacts over which they pass. This movement is effected by the so-called disconnecting-magnet 38, the poles of which attract the lower part of the frame. The construction is identical with one form of that described in Specification 19,553. Impulse sender. The rotary arm 90 of the impulse sender carries two contacts 80, 81, of which the contact 80 successively engages the earthed contact segments 95, 96, 97, 98, thus earthing the line 78, whilst the contact 81 engages the divided contacts 91, 92, 93, 94. The set of contacts 91 transmits a fixed number of impulses to operate the preliminary selector, and the sets 92, 93, 94, one or more of which can be earthed by the devices 103, 104, 105, send impulses corresponding to the hundred, tens, and units digits of the wanted subscriber. The contact 99 causes the application of ringing-current to the called subscriber. The impulse sender is automatically released by the removal of the receiver. General operation. The subscribers' lines 78, 79 terminate in the exchange in a relay set 110, 111, 112, 113, which repeats the selecting-impulses to the co-operating magnets 12, 13 of the preliminary selector I, group selector II, and final selector III. Fig. 3 shows the apparatus in its normal position, except that the contact-springs on the left are shown in the position they assume after the first movement of the ratchet-bar 41. Fig. 4 shows the connexions daring a conversation, the terminals of the two batteries 106, 108 being represented in Fig. 3 by the symbols -, Œ, +, respectively. Preliminary selector. The calling subscriber A, having set the pointers 103, 104, 105 to indicate the number of the wanted subscriber, releases the impulse sender by removing his receiver. The contact 80 first engages the segment 95, thereby energizing the relays 113, 112, which complete over the contacts 115,118 a circuit for the detent magnet 13 of the preliminary selector. Immediately afterwards, the line 79 is intermittently earthed over the contacts 91, and the relays 110, 111 repeat these impulses to the lifting-magnet 12. The first impulse passes over the contacts 114, 117, 61 to the magnet 12, which closes at 56 a circuit for the disconnecting-magnet 38, which raises the wipers 1, 2, 3, 4 off the contact bank. If the first group selector is engaged, the magnet 38 remains energized over the contacts 51, 52 and the test roller 6, so that the second and succeeding impulses pass over the contacts 114, 117, 53 to the magnets 12, the contact 61 having been opened on the first movement of the selector. When an idle group selector has been found, the magnet 38 de-energizes, opening contact 53 so that the rest of the first set of impulses do not reach the magnet 12. As the contact 80 passes off the segment 95, the magnet 13 releases its armature, the simultaneous de-energizing of the magnets 13, 38 allowing the wipers 1, 2, 3, 4 to engage the terminals of the idle group selector. Group selector. When the contact 80 engages the hundreds segment 96, the relays 112, 113 energize the magnets 13 of the preliminary and group selectors. The impulses sent by the contact 81 are repeated by the relays 110, 111 over the contacts 114, 117, 133 to the magnet 12 of the group selector, the magnet 12 of the preliminary selector being disconnected at the springs 61 of this selector. The first of these impulses passes over the spring 61 to the magnet 12, which closes at 56 a circuit for the disconnecting-magnet 38, which locks up over the armatures 145, 146 as long as the magnet 13 is energized, and closes a contact 53 so that the second and following impulses pass over this contact, the contact 61 having been opened on the first movement of the selector. In the system described, the group selectors have no rotary hunting movement, each group selector being assumed to have access to ten final selectors, which cannot be appropriated by other group selectors. Final selector. When the contact 80 engages the tens segment 97, the relays 112, 113 energize the magnets 13 of the preliminary, group, and final selectors. The impulses sent by the contact 81 are repeated by the relays 110, 111 over the contacts 114, 117, 133, 137 to the magnet 12 of the final selector, the magnets 12 of the preliminary and group selectors being disconnected at the springs 61 of these selectors. The circuit of the disconnecting - electro - magnet 38 is closed by the magnet 12 and is maintained over the armatures 145, 146 as long as the magnet 13 is energized. As the contact 80 passes from the segment 97 to the unit segment 98, the magnet 13 of the final selector is de-energized for a time, thereby shifting the actuating-mechanism, as described in Specification No. 410/12, in such a way that the following set of impulses received by the magnet 12 causes the wipers to move in a different direction, and thus to select the required line according to the units digit. Busy test. As the contact 80 leaves the segment 98, the magnet 13 of the final selector opens the circuit over the armatures 145, 146 of the disconnecting magnet 38, which, however, remains energized over the test roller 6 if the desired subscriber is engaged. Basy signalling current is thus supplied from the transformer 156 over the armatures 153, 154 of the magnet 38, wipers 1, 2, and armatures 123, 124 of the relay 110, 112, to the calling line. Ringing-current. While the contact 80 engages the segment 99, the relay 110, 112 is again energized, and by attracting its armatures 123, 124 supplies ringing-current over the leads 127, 139, and 128, 140 to the called line. Supply of microphone current. When the impulse - sender reaches its normal position, the microphone 67 receives current through the relays 110, 112, 111, 113. The called subscriber's line is also supplied with current through a similar circuit. Metering arrangements. The calling subscriber's register 148 is connected, by the movement of the preliminary selector, to the branch 128, 140 of the talking-circuit, and when the called subscriber replies, his line relay, corresponding to the relay 113, closes a contact, such as 151, which completes the circuit of the register. Release. When either subscriber hangs up, the movement of the switch-hook momentarily grounds the line 79, thereby energizing the relays 110, 111, which close circuits for the magnets 12 of all the selectors over the back contacts 54 of the magnets 13. The magnets 12 lock-up over the armatures 57, 55 and off normal switch contacts 60, and also energize the disconnecting-magnets so as to lift the wipers off the contact banks during the release of the selectors. By arranging the hookswitch between the impulse-sender and the line wires, the connexion may be released at any stage by simply replacing the receiver. Modifications. A modified system is described in which the currents energizing the magnets 12, 13 pass over part of the talking circuit, the number of selector wipers being diminished.