Patent GB-190209876-A (GB)
Title: Improvements in and relating to Railway Block Signalling Systems.
Inventor: MARKS GEORGE CROYDON
Filed: 1902-04-29
Granted: 1902-08-14
Abstract: 9876. Marks, G. C., [Chapman, W. M., and Pestell, W.]. April 29. Signalling a n d communicating between trains; semaphore signals; lamp signals; indicating movements of trains; indicators and repeaters, signal ; electric railways, signalling on.--Relates to electric block - signalling systems for electric or other railways. A signal arm or target 1 is provided at each end of the block section A, B, the two signals being moved from normal to one or other of two distinctive positions on the entrance of a'car into the section, and returned to normal when the car leaves the section. Preferably, each signal is coloured differently, say, red and white, on its two sides, its normal position being edge on to an approaching car, and its distinctive positions being at right-angles to the normal position. The signal is fixed to the core 2 of the operating-solenoid 7, and its rotation from the normal position, when the magnet is energized, is effected by the engagement of one or other of two studs 5, 6 with its corresponding groove 3 or 4 in the core 2. The pins 5, 6 are fixed to the yoke 7a on the lever 8, which is normally held by the spring 10 so that the pin 6 engages in the groove 4, this being the condition for displaying the red side of the signal. For the movement of the signal to display the white side the lever 8 is drawn over by the armature 11 of the electromagnet 14 to engage the pin 5 in the groove 3. Instead of pins and grooves, threads &c. may be employed. When set to display either white or red, the signal is locked by the lever 17 falling under the shoulder of the core 2. The release of the signal to allow it to return to normal, is effected by the electromagnet 22, the armature 20 of which has an operating-pin 21 engaged behind the lever 17. Fig. 3 shows the operative connections with the trolley wire or other feeder 25, the return wire 26, and the line wire 27. When a car enters the section, say, at the end A, it closes a contact 53 connecting the feeder 25 to the lead 54, momentarily completing the circuit of the electromagnet 14, which draws its armature 11 and the lever 8 into the position shown. In this position the lever 8 is locked by the hook 23 on the lever 20, while the armature 11 completes, at the contacts 42, 31, a circuit through the auxiliary coil 44 of the electromagnet 14 and the solenoid 7 of B's apparatus as follows :-25, 48, the counterbalancing - spring 47 of the core 2, the insulated plate 46 on the core, the fixed contact 45, lead 43, and coil 44, thence through 42, 31, 27, 16, 49, 35, 7 (of B's apparatus), 36, 50, 52, 51, 39, 40, 26, so setting the signal at B to display its red side to a car approaching in the opposite direction. This signal is then locked by its latch 17, which breaks the circuit at 36, and de-energizes the magnets 7 at B and 44 at A, the armature of the latter breaking the contacts 42, 31 and connecting the contacts 32, 34 in the circuit of the coil 7 at A. The operative circuit of this coil is also closed by an arm on the plate 46 of the signal at B engaging the contact 33, the circuit being from the feeder 25 through 48 (at B), 46, 33, 30, 27, 32, 34, 35, 7, 35, 36, 37, 38, 39, 40, 26. As the lever 8 is locked by the hook 23, with the pin 5 engaging in the groove 3, the current through this circuit sets the signal at A to display its white side ; the signal is then locked by its lever 17, and its operative circuit is broken at 36. The setting of the signal at the entering end of the section is thus made dependent on, and serves as an indication of, the setting of the signal at the distant end of the section. The signals are released and return to normal when the car leaves the section at either end, the car, in leaving, closing a contact 53<a> between the feeder and the lead 55 of the unlocking- magnet 22, which is connected to the return wire through the contacts 56, 58, 59, the contacts 58, 59 being held closed by the flange 61 on the signal. The two leads 55 are connected by a lead 61<a>, both magnets 22 being energized by the closure of one of the contacts 53<a>. In case only one of the magnets is energized by the momentary contact at 53<a>, its armature 20 completes at the contacts 63, 56 a circuit through the other, this circuit being fed through the lead 62. When the signals return to normal, the releasing-circuits are broken at the contacts 58, 59. A lamp 64, the circuit of which is completed at the contact 66 by the plate 46, may be employed to illuminate the signal, or white and red lamps 67, 68, giving distinctive signals, may be employed. In the latter case, the arm of the plate 46 closes at the contact 71 or 72, the circuit of the lamp corresponding to the position in which the signal is set. These lamps may also be used in substitution for the signal arm. In another arrangement, two or more cars travelling in the same direction can be admitted into the section at the same time, the signals being returned to normal only when the last car leaves the section. The releasing-circuits are made dependent on the movements of a controller, which consists of a ratchet - wheel mechanism, adapted to close a contact in the releasing circuit. The second car, and each following car, which enters the section, moves the ratchet-wheel through the space of one tooth away from the contact-closing position, and each car leaving the section returns the ratchet-wheel through the space of one tooth towards that position. When the last car leaves the section, the signal at the entering end is first returned to normal, and then the signal at the other end is returned. A bell is rung by the second and following cars entering the section. In case a car enters a section at the same instant that another car leaves it, the ratchet - wheel is moved away from the contact - closing position through the space of one tooth, and then returned through the same distance. A controller is provided at each end of the section, but only that at the entering end of the section becomes operative.