Patent GB-190008678-A (GB)
Title: Improvements in or relating to Electrical Signalling Apparatus.
Inventor: ALCOCK ALFRED UPTON
Filed: 1900-05-10
Granted: 1901-08-10
Abstract: 8678. Alcock, A. U. May 10. Grant of Patent refused. Signals, electric, indicator or visible, bell, and reply or tell-tale.-Relates to electric apparatus of the kind described in Specifications Nos. 934 and 14,224, A.D. 1899, for transmitting orders, signals, &c., the transmitter and receiver being connected by three line wires, and the indicator of the receiver being caused to rotate by an arrangement of electromagnets, the magnetic field of which turns or rotates in accordance with the movements of the transmitter. In the present invention, the transmitter a, Fig. 1, is normally disconnected from the receiver b at the automatic switch f, but is connected by the switch to the receiver when the handle t of the transmitter is operated to transmit a signal. The contact-making armatures 22, 23 of the switch are arranged between the pole-pieces of three upper and three lower horizontal electromagnets 14, 15, 16, 17, 18, 19, and when raised from their normal position connect the leads 11, 12 from the transmitter through the contacts 25, 25<a> with the line wires c, d. The line wire e is normally connected to the lead 13. When the handle t of the transmitter is operated, the cam surfaces 29<a> complete, between the contacts 28, 27, the local circuit 26 through the electromagnet 14, which raises the armatures 22, 23 to the connecting position, the armatures being then held up by the electromagnets 15, 16, which are preferably connected as shown to the line-wires. The indicator g has a soft iron armature mounted between the polepieces of two of the electromagnets, and is moved into indicating position when a signal is sent. The line-wires are connected to the coils of the receiver, and also to the coils 63 of a relay h, which closes a local bell circuit l. On the reception of a signal, the operator at the receiving end closes the short-circuiting-switch n, on which the bell circuit l is cut out, the electromagnets 17, 18, 19 draw down the armatures 22, 23 to disconnect the line-wires, and the indicator g returns to its normal position, the indicator of the receiver remaining in the position to which it was moved until another signal is transmitted. The local circuit 26 can be broken, when required, at the hand-operated switch r. Two or more receivers or sets of receivers may be connected to the same transmitter, in which case the various switches f, r can be mounted on the same switchboard. Transmitters and receivers of the construction described in the prior Specifications above quoted may be employed. Fig. 4 shows another form of automatic switch, in which the leads 11, 13, 12 are connected to the line-wires c, e, d through the armatures 34. The armatures are raised by the electromagnets 37 in the local circuit 26, are held up by the electromagnets 39, and are disconnected by the electromagnets 41 when the line-wires are short-circuited. Fig. 6 shows a form of receiver, in which six electromagnets are arranged parallel to each other around a central polarizing coil 47, mounted between the sector-shaped armatures 45 on the spindle 46 of the pointer 48. The coil 47 with its casing 50 can be inserted in and removed from position, and is energized from the local bell circuit l through the lead 54<a>, the contacts 54, 53, and the casing of the apparatus. In another form, the coils 43 are arranged end to end, in hexagonal form, the armatures 45 being on opposite sides of the spindle 46. The spindle 46 may be held stationary after operation by a spring brake, which is released by the electromagnet 47 when another signal is received. In the arrangement shown in Fig. 10, the line-wires c, d, e are not short-circuited until the pointer 83, of a tell-tale instrument having a commutator 78 similar to that of the transmitter, is moved into a position corresponding to the signal received, and the hand-switch 82 is also, closed. The magnet 81 of the short-circuiting switch is in a local circuit 66, which is normally broken at 82, and is also broken at the armature 80 by the action of the coils 76 when a signal is received. The movement of the tell-tale instrument to the corresponding position causes the magnets 77 to neutralize the magnets 76, on which the armature 80 closes, so that, when the switch 82 is also closed, the circuit 66 is completed and the short-circuiting switch closed. Figs. 11 and 14 show a form of commutator for the transmitter, applicable for transmitting twenty-four different orders or signals. Connection with the leads 11, 12, 13 3 is effected through the insulated collars 4, 5, 6. The main contact-disc consists of three insulated segments 85, 86, &c., each of an angular length of 105‹, and separated from each other by insulating-blocks 88. The supplementary contact-disc has three pairs of L-shaped contacts 90, 91. arranged opposite to the insulating-blocks 88. Each contact 90 or 91 is of an angular length of 30‹, and is connected to that contact on the main disc which is immediately in front or in rear of, but not in line with, itself. The brushes 95 of the main contact-disc are connected to the poles of a battery, the number of cells of which is preferably divisible by four, while the brushes 97 are connected to the poles of intermediate cells, so as to include one quarter of the cells at each end between them and the connections to the brushes 95. The overlapping of the ends of tLe supplementary contacts enables the connections between the coils in the receiving-instrument to be prolonged until the pointer of the transmitter has passed across the boundary line between two signal indications on the dial. In another arrangement, the main contacts are overlapped, and the ends of the supplementary contacts are parallel, resistances being interposed i,etween the contact-brushes and the battery to vary the current ratio. In another commutator capable of transmitting twelve orders, three contact-segments are employed, which overlap at their ends to the extent of 30‹. The effect of the overlapping may also be obtained by making the contacts parallel at the ends and employing, instead of each single contact-brush, two brushes spaced apart so as to cover an angular length of 15‹ (for twenty-four signals), or 30‹ (for twelve signals). Other constructions of commutator are described, in which the leads 11, 12, 13 are connected to contact-springs, operated by cam discs on the transmitter spindle, to connect the leads, as required, with one or other of the poles of the electric generator.