Patent GB-190623516-A (GB)
Title: Improvements in Railway Signalling Apparatus.
Filed: 1906-10-23
Granted: 1907-10-10
Abstract: 23,516. Lake, H. H., [Hall Signal Co.]. Oct. 23. Transmitting power.-A three-position semaphore arm is operated by two cylinders and pistons so arranged that one piston lifts the other cylinder and piston in operating the signal from danger ' to caution,' and the second cylinder is moved to operate the signal to 'clear'; the arm is held by electromagneticallyoperated detents in both positions, and the detents are mechanically connected so that, if the 'clear' detent is released, the caution' detent is also released and the signal arm goes from clear' to 'danger' in one movement. The valves are electro-magnetically controlled. A normal safety automatic system in which such signals are used is shown in Fig. 11, and the construction of the operating-mechanism is shown in Figs. 1 and 2. The gas is derived from a storage tank and passes to the valve 31, shown in detail in Fig. 8, which passes gas to the lower motor cylinder 10 and to the similar valve 67 which passes gas to the upper motor cylinder 13. The valve 31 is opened by the electro-magnet 51, Figs. 1 and 2, 63,118,127, Fig. 11, when the section protected by the signal is clear and the relay 99, 117, 123<a> is therefore energized. The electromagnet 51 draws its armature 46 and lifts the rod 45 and the spindle 42 of the valve 31, thus opening the conduit 32 through the port 33 and valve opening 34, 35 to the pipe 37 and cylinder 10. The piston 15 of this cylinder has a seating 22 on which rests the cylinder 13 of the upper motor, which is thereby bodily raised and is directly connected to the thrust-rod 8 of the semaphore arm 1. The seating 22 carries a roller 52 which when the stroke is completed knocks away the detent 56 and allows the bell crank 53 to rotate about its pivot and to lower the rod 54 attached to the end of the rod 45, which is thus moved about its end attached to the rod 49 and moves the valve-rod 42 to open the cylinder 10 to exhaust through the lower valve seating 40. The signal is held at 'caution' by the detent 57, which is pivoted to the frame on a pin 58 and operated by the extension 66 of the armature lever 63 pivoted to the frame engaging a roller G2 on its upper end. The signal is operated from 'caution' to 'clear' by the admission of gas to the upper cylinder 13 through the valve 67 actuated by the electro-magnet 71, Fig. 1, 105, 119, 129, Fig. 11, when the section ahead of that controlled by the signal is also clear, and the two track relays 99 are energized, thus completing the circuit for the signal of section B from the battery 113 through the switch arm 112, switch 111 (closed by the armature 63 of the signal section C), wires 110, 109, switch 107 (closed by the armature 63 of signal section B), magnet 105, and wires 115, 114. The magnet 71 also operates the lever 77 pivoted to the arm 79 on the shaft 78t and places the detent 74 to hold the latch 75 attached to the cylinder 13, which is lifted to the gas while the piston 15 serves as a fixed abutment. The arm 79 is held in the required position by the stop 84 engaging a stop on the arm 82 fast on the shaft 78, which also carries a counterweight 80. If the detent magnet 51 is de-energized when the signal is at 'clear,' the weight of the parts of the operating-mechanism is thrown on the detent 74, which causes the arm 79 to rotate the shaft 78 until the latch on the cylinder 13 is at 'clear.' The signal thus moves to 'danger' in one movement in the event of a train backing on to a section. In one form of the apparatus, the upper cylinder is supplied with gas by a flexible pipe passing through the collar 22, and in another form, shown in Fig. 10, a pipe 94 passes through the lower cylinder to the piston-rod 88, which is bored to fit it so as to form a telescopic joint.