Patent GB-190120132-A (GB)
Title: Improvements in Railway Signalling Apparatus.
Inventor: HADDAN HERBERT JOHN
Filed: 1901-10-08
Granted: 1902-09-25
Abstract: 20,132. Haddan, H. J., [Hall Signal Co.]. Oct. 8. Semaphore &c. si,gnals; controlling and locking signals ; signalling &c. between trains ; contacts, electric.-Relates to signalling - apparatus particularly for use on rail ways. The signals are counterweighted so that they have a bias towards the normal 'danger' position, and are moved to 'line clear' by gas pressure derived from a tank of liquefied gas. Preferably, a separate supply tank is provided for each signal, and the tanks are made detachable from the apparatus to permit of recharging &c. The gas pressure may act on a piston, turbine, or the like to lower the signal, and the connections and controlling-mechanisms may be varied. The accompanying Figures show two arrangements, in which the signal arm is operated by a piston, and the operation is controlled automatically by track circuits. The tank 5, Fig. 1, containing the liquefied gas, is connected through the union 9, reducing-valve 8, and pipe 7 with the lower end of the cylinder 4, in which works the piston 3 connected to the operating-rod 2 of the signal 1. The rod 2 carries a hood 10 provided with a catch 11, which, when the signal is lowered, passes and engages above the armature 12 of the electromagnet 13, to hold the signal at 'line clear.' The hood 10 is also provided with slotted arms 18, 25, which respectively control the pressure-supply valve 14 in the pipe 7 and the exhaust valve 21. The valve 14 has a weighted lever 15, which is normally supported by the armature 17 of the electromagnet 16. The magnets 13, 16 are arranged in parallel in a circuit normally open at the relay 27 and closed at the relay 28, the relays being controlled by electromagnets 29, 30 in track circuits. When a train enters the track section 31, the relay 27 closes and completes the circuit through both magnets. The magnet 16 releases the armature 17 from the lever 15, which then falls and opens the valve 14, so admitting the pressure to the cylinder to lower the signal In the upward movement of the rod 2, the circuit of the magnet 16 is broken at the contact 33, and the valve 14 is closed by the arm 18, which raises and re-sets the valve lever 15. The catch 11 also passes above the armature 12, which is held by the magnet 13, and locks the signal at line clear.' At the same time, the arm 25 opens the exhaust valve 21. When the train enters the section 32, the circuit of the magnets 13, 16 is broken at the relay 28, and the magnet 13 releases the armature 12, so permitting the signal to go to 'danger.' In its return movement, the arm 25 closes the valve 21. In the arrangement shown in Fig. 2, the signal is held at 'line clear' by the gas pressure. The gas-supply and exhaust valves are mounted on the spindle 49 connected to the armature 53 of the electromagnet 54. When the magnet is energized, by the closing of the track relay 56, the exhaust valve is closed, and the inlet valve is opened, so admitting pressure to the cylinder to move the signal to, and hold it at, 'line clear.' When the magnet circuit is broken at the track relay 57, the valves are returned to normal position by the spring 52, and the signal goes to danger.' An automatic block signalling- arrangement, in which either of these signal mechanisms may be employed, is also described. The controlling-circuit of each signal includes one normally-open and two normally-closed track relays, the closed relay furthest in advance being opened by the electromagnet which closes the open relay of the next signal in advance.