Patent GB-190228950-A (GB)
Title: Improvements in Electrical Signalling Apparatus for Railways.
Inventor: MACKENZIE JOHN WILLIAM
Filed: 1902-12-31
Granted: 1903-12-31
Abstract: 28,950. Mackenzie, J. W., [Miller, J., Stiles, T. G., and Kelloway, C. J.]. Dec. 31. Signalling between trains ; semaphore signals.- An electric semaphore in an automatic block electric system of signalling is provided with the means shown in Fig. 2 to restore the semaphore to danger by a motor, if the magnet, when de-energized, fails to release the semaphore so as to allow it to return by gravity. Fig. 10 shows diagrammatically the signals in three blocks with the wiring and circuits used in a threeposition signal system. The slot-magnet E controlling the signal and adapted to be energized and de-energized by the movement of trains over the blocks is mounted on the pinion or gear segment e', which engages with the rack f<1> on the signal rod F. The pinion e<1> carries the arm or extension e<4> provided with the locking and releasing device controlled by the armature e<3> of the magnet. The driving-gear C having pins c<1>, c<2> or other means for engaging with an escapement lock e<9> on the mechanical member of the slot is rotated by the motor A, and is placed eccentrically with regard to the pinion e' of the slot. By the rotation of the gear C, the pin c<2> makes contact with the primary locking-device on the member of the slot which moves the armature into contact with the slot-magnet, and also moves the escapement lock of the slot into its locked position. The adhesion of the armature e<3> to the magnet prevents the primary clocking-device from moving back, and thus keeps the escapement lock in its locked position, so that when the pin of the driving-gear reaches the escapement lock of the slot it carries the latter with it, and rotates the pinion meshing with the rack f<1> on the signal rod, driving the signal to clear. A train entering the block controlling the signal de-energizes the slot-magnet, and also puts the motor in circuit, and the signal is free to return to danger. If the signal returns to danger, the movement cuts the motor out of circuit, but if the armature sticks, the motor starts up and the pin c<1> on the driving- gear comes in contact with the restoring-arm h<2> and causes the restoring-pinion h<1>, which engages with the opposed rack f<2> on the signal rod F, to move the rod down. This movement restores the signal to danger, and also restores the slot E to its proper position through the rack f<1> and the parts to their normal working condition. For a three-position signal, there are two retaining-means G<1> for the mechanical member of the slot, one for the caution position, the other for the clear position, and there are two driving-pins c', c<2>. When a two-arm signal is used, another slot and restoring mechanism is provided on the other side of the driving-gear which serves for both signals. One driving-pin on each side is used, and the restoring-arm is provided with a magnet and a spring to move it into and out of the path of the pin carried by the driving- gear. Fig. 3 shows the arrangement of the parts for a two-arm signal. The motor A, Fig. 10, is connected with the battery J by the wire j', while the slot magnet is connected with the battery by the wire j<2>. The relay K controlling the finger j<3> is energized from the track battery J<1>. The finger j<13> is connected with the motor, and is operated between the contacts j<7>, j<10> by the fluctuation of the signal rod obtained through the camj<15>. The second relay controlling the finger j<12> is connected with the battery J of the succeeding block. When two-arm signals are used, the wiring shown in Fig. 10 operates the upper or danger arm while the lower or caution arm is controlled by a second finger j<3> of the relay K, and a second arm j<13> controlled by the movement of the signal rod. The armj<13> can be constructed to break the circuit for the motor as soon as the armature leaves the signal, or it can be constructed to break the circuit when the semaphore is horizontal. In the primary locking-device, the pushing-pin e<27> may be omitted and the pins c', c<2> may engage directly with the arm e<26>. The retaining-lock e<15> can be made in the form of spring catches on the framework. The signal base may be removable, carrying the operating-gears, slot-mechanism, and dash-pot for the signal rod, and a track may be provided for the base to travel on so that it can be iturned when the parts are disconnected.