Patent GB-346017-A (GB)
Title: High speed fork regenerating repeater for telegraph systems
IPC: H04L25/46
Filed: 1929-10-31
Abstract: 346,017. Code telegraphy. WESTERN UNION TELEGRAPH CO., 190, Broadway, New York, U.S.A. Oct. 31, 1929, No. 33139. Convention date, Aug. 30. [Class 40 (iii).] In a signal-receiving system in which the received impulses may be attenuated or distorted, a member vibrating between adjustable contacts is arranged so that a regenerating or repeating relay whose primary winding is connected to the armature of a line-receiving relay responds to a selected portion of the impulse which operates the receiving relay. The regenerating relay, energized whilst the vibrating member is in the gap between the contacts, is provided with a secondary winding energized over the contacts of its armature and arranged to reverse the current through the receiving relay when the line current falls to a low value approaching zero. Receiving and regenerating system. Signal impulses received over a line 1 energize the primary winding 2 of a receiving relay 3 whose armature 4 operates to a marking or spacing contact connected to battery. Current passes from battery through a resistance 8 and a switch 9 to the primary winding 21 of a regenerating relay 22, when a contact tongue 13 mounted on the tine of a tuning fork 14 is in the gap between adjustable contacts 11, 12. The armature 26 of the relay 22, energized when the tongue 13 is in the gap position, connects marking or spacing current to an outgoing line 28 and locks up over a secondary winding 25. At the same time current passes through a line 30 to a secondary winding 33 of the relay 3 tending to operate the armature 4 to its opposite contact. The current through the winding 33 is delayed by a variable condenser 34, and the windings are so arranged that the armature of the relay 3 is not operated until the line current has fallen to a low value. When two successive impulses are of the same polarity, the current through the coil 21 will be interrupted whilst the tongue 13 engages the contacts 11, 12 but the armature 26 will be maintained against the appropriate contact by the locking winding. The contacts 11, 12 may be adjusted so that a suitable portion of the received impulse is selected for regeneration. A shunt path round a condenser 36 is opened by the key 9, and during the charging of the condenser, current will normally pass through the winding 21 and an indicating galvanometer 24, when the tongue 13 is in the gap position. The contacts are adjusted so that the condenser is charged whilst the tongue 13 is in engagement with a contact 11, 12 and no current flows through the galvanometer 24 when the tongue is in the gap position. After adjustment, the shunt path around the condenser 34 is closed by the key 9. Synchronizing arrangements. The tuning fork 14 is adjusted to vibrate at a rate slightly greater than the impulse frequency, and a retarding force is periodically applied when necessary to maintain synchronism. During the movement of the armature 4, the tongue 13 should be in engagement with one of the contacts 11, 12. An armature 46 operated by a relay 45 connected in series with the primary winding 2 will normally be operated in synchronism with the armature 4, and, in its gap position, will connect positive battery to two windings 49, 50. If the tine of the tuning fork is in engagement with one of the contacts 60, current will flow through the windings 49, 50, and the current in the winding 50 is adjusted to operate an armature 53 to its marking contact. A circuit will be completed through a switch 56 and a sounder 59, but a brake magnet 16 will not be energized. If, however, the tine has left a contact 60, the current in the winding 49 will operate the armature 53 to its spacing contact, and a circuit will be completed to energize the braking magnet 16 which retards the fork 14 until synchronism is restored. The phase of the fork may be altered with respect to the incoming signals by a circuit 42 including a variable condenser 43 so that the selected portion of the signal impulse may be changed as regards its position in the impulse period. In an alternative synchronizing arrangement, Fig. 8, the fork is arranged to vibrate at the signalling frequency when an intermediate braking force is applied. If the fork runs too rapidly or too slowlv this force is increased or decreased. If the tine of the fork 61 has just left a contact 90 and an armature 87 of a relay 88 is in mid-gap position when the correcting impulse flows, current will flow through the windings 71, 73 of relays 69, 70 and the armatures 67, 68 will engage their left hand contacts. Current will flow through the braking magnet 62 to provide an intermediate braking force corresponding to the correct speed of the fork. If the tine is in engagement with one of the contacts 90, the relay 88 will be energized, and current will flow through a winding 72 to operate the armature 67 to its right hand contact. The increased current through the braking magnet will augment the braking force. If, however, the relay 88 has completely de-energized when the armature 77 is in the gap position current will flow through winding 74 and operate the armature 68 to its right hand position. No current will flow through the braking magnet 62, and the fork will be accelerated until synchronism is restored. The phase of the operation of the relay armature 77 is adjusted with respect to the received impulse by a variable condenser 81.