Patent GB-191423380-A (GB)
Title: Improvements in or relating to Telegraph and like Signalling Systems.
Inventor: DIXON THOMAS BULLITT
IPC: H04L25/26
Filed: 1914-12-01
Abstract: 23,380. Dixon, T. B. Dec. 5, 1913, [Convention date]. Receiving and repeating systems; relays; siphon recorders.-Relates to the construction and arrangement of selenium-cell relays for use in receiving or repeating systems. A broad beam of light simultaneously illuminates two selenium cells so that the movement of the beam of light increases the resistance of one cell and decreases that of the other, the cells being connected in a branched circuit, or in a Wheatstone bridge circuit, in such a way that the whole of the effect due to the change of resistance of the cells is available for use in reversing the current through the recording or repeating instrument. One of the cells may be replaced by a resistance, or more than two cells may be used. A magnetic shunt may be connected across the recording or repeating coil controlled by the selenium-cell relay. Curbing- windings provided on the receiving-coil are influenced by movement of the recording or repeating instrument controlled by the selenium-cell relay. As shown in Fig. 1, the light from an arc 11 is reflected by the mirror 7 of the receiving-instrument 6 on two selenium cells arranged in circuit with adjustable resistances 33, 34, and a moving-coil recorder or repeater 20. Curbing and re-transmitting arrangements. In the system shown in Fig. 1, the siphon 21. may carry a contact 24 controlling re-transmitting relays 27, 28. In the system shown in Fig. 6, the recorder is replaced by a moving- coil relay forming the subject-matter of the divided Application 100,074. In this arrangement, movement of the coil 20<a> in one or other direction closes the circuit of one or other of the re-transmitting relays 58, 58<a>. The coil 6 of the selenium-cell relay 14 is provided with a supplementary winding 63 arranged in parallel with the coil 20<a> in a circuit 64 which includes reversing-contacts of the relays 58, 58a. During the first movement of the coil 6, the direction of the current produced in the circuit 64 is such as to assist its movement, but, when the relay 20<a> operates either the relay 58 or 58<a>, this current is reversed to curb the movement of the coil 6. In the modification shown in Fig. 8, the re-transmitting-relays 58, 58<a>, Fig. 6, are replaced by paits of relays 58<e>, 58<f>, and 58<i>, 58<k> which control pivoted levers having jockey rollers 67 and reversing-contacts in the curbing-circuit. The arms 44 of the moving-coil relay 20a arc provided with contacts on each side of the tongue 42, these contacts being respectively con nected to the magnets operating the pivoted levers. The pivoted levers may have adjustable weights 66 to vary their normal rate of movement. During the movement of the arm 40 of the relay 20a to the left, the magnet 58<e> is energized, but as soon as the arm 40 begins to move back, the magnet 58f reverses the position of the pivoted lever. An inductive resistance 68 and shunted condenser 69 are placed in the curbing circuit in order that its curbing- action on the coil 6 may be suitably tuned or timed. The Specification as open to inspection under Section 91 (3) (a) also describes the construction of the relay 20<a>, Fig. 6, which forms the subjectmatter of Specification 100,074. In the form shown in Fig. 9 (Cancelled), the coil 20<a> carries an arm 40 having insulated pieces 41, 41<a>, adapted to engage contact pieces such as 42 carried by freely-swinging arms 43 on shafts 47 mounted in jewelled bearings. The contacts 42 rest between a contact 45 and a stop 46 carried by the forked end of an arm 44 on a shaft 47<a>, which is mounted to rotate with slight friction, this being secured by friction springs 50. A spring 55 normally presses the contact 42 against the stop 46 on the arm 44, movement of this arm being prevented by a fixed stop 52. When the arm 40 moves in one direction, the contact 42 is at once moved against the contact 45, thus closing the local circuit. As the arm 40 continues to move, the arm 43 carries the arm 44 with it, the local circuit being kept closed, but as soon as the coil 20<a> begins to swing back, the contact 42 is moved away from the contact 45, owing to the friction of the shaft 47<a>, thus opening the local circuit. In the modified contact-mechanism shown in Fig. 12 (Cancelled), the arm 40 of the moving coil is connected by fibres 73 to pivoted levers 72 connected by fibres 76, 77 to a forked arm 44, mounted as shown in Fig. 9. Arms 43 are provided with contact-segments 70 which normally engage insulating parts of similar segments 71 on the levers 72. When the arm 40 moves, one or other of the segments 70 makes a rolling contact with the conducting-part of the segment 71. This subject-matter does not appear in the Specification as accepted.