Patent GB-190114952-A (GB)
Title: Improvements in or relating to Railway Signalling Apparatus
Inventor: BOULT ALFRED JULIUS
Filed: 1901-07-23
Granted: 1902-07-03
Abstract: 14,952. Boult, A. J., [Neelemans, A.]. July 23. Semaphore &c. signals ; controlling &c. signals ; indicators and repeaters, signal.-Relates to means for making and breaking the motor circuit of electricallyoperated signals, and to selecting- mechanism for enabling any one of a series of signals to be operated by the same train of gearing. The motor 2, Fig. 1, is geared to the spindle 3, which is connected by a chain on the chain sheave 4 and the rod 111, Fig. 5, to the balance lever 110 of the signal. Above the spindle 3, a bar 8 is mounted by its lugs 9, 10 on the guide-rod 7, which also carries a sliding block 20 controlled by the spring 21. The block 20 carries two contact-springs 22, which, as shown in Fig. 3, connect the contact-plate 23 with one or other of the contact-plates 24, 25, according to the position of the block. The bar 8 is provided with three pallets 11, 12, 13. The two pallets 11, 12 are adapted to be engaged by the tappet 14 on the disc 16, and the third pallet 13, which is out of alignment with the other two, is adapted to be engaged by the tappet 15 on a second disc 16, both discs 16 being adjustably secured on the spindle 3. When the signal is moved by the motor from the normal to the line clear' position, the spindle 3 and the sheave 4 are rotated clockwise through a revolution during which the tappet 14 engages the pallet 12 and moves the bar 8 to the right. In the first part of the movement of the bar, the block 20 is held by the latch 26, 27, but, when the lug 9 engages the incline 28, the latch is released, and the block 20 is thrown over by the spring 21 against the lug 10. This movement of the block disconnects the contacts 23, 24 in the motor circuit, and connects the contacts 23, 25 in the distant-signal circuit, the break between the contacts 23, 24 being effected rapidly and through a large air-gap, so as to prevent the formation of an arc. The break is shunted through the high-resistance coils of the brake magnets, by which the signal is held at ' safety.' When the brake circuit is broken in the cabin, the signal is returned by its counterweight to 'danger,' the tappet 15 engaging the pallet 13 and moving the bar 8 and block 20 so as to disconnect the contacts 23, 25 and to connect the contacts 23, 24. This re-establishes the motor circuit, and also the circuit of an indication magnet, which is energized by the current developed in the motor during the latter part of the return movement. This current also serves to retard the return of the signal, so preventing shock. If, through excess of momentum on the return movement, the tappet 14 engages the pallet 12 and throws the bar 8 too far to the left, the tappet 14 will, at the beginning of its next forward movement, engage the tappet 11, and bring the bar to the correct normal position. Fig 5 shows the selecting-mechanism. The various signal arms on the post 101 are connected by rods to the eyes 108 of corresponding levers 106 pivoted on the pin 104, which also carries the counterweighted lever 110 actuated by the motor. Each lever 106 is provided with a clutch or catch lever 112, and the lever 110 is provided with a pallet 115 of sufficient width to be engaged by any one of the catches 112. The catches are controlled by separate electromagnets 117, the circuits of which pass through the motor and are controlled by suitably-interlocked levers in the cabin. To lower a particular signal, the circuit through the corresponding electromagnet 117 is completed in the cabin, and the catch 112 of the corresponding lever 106 is thus brought into position to engage the pallet 115, so that, as the arm 110 is moved by the motor, the operating-lever 106 of the desired signal is carried with it and lowers the signal. On the return of the signal to 'danger,' the catch 112 is released from the tappet 115 by the incline 118 on the tappet engaging the incline 119 on the catch.