Patent GB-190419482-A (GB)
Title: Improvements in Electric Automatic Block Signal and Safety Systems.
Inventor: FINNIGAN GEORGE P
Filed: 1904-09-09
Granted: 1905-02-02
Abstract: 19,482. Finnigan, G. P. Sept. 9. Automatic systems; semaphore signals; locking signals; stopping engines and trains; contacts, mechanical. -An automatic block system is described, employing track circuits and semaphores which are electromagnetically actuated and locked, together with similarly actuated. train-stopping devices. Each block section is provided with a train-stopping lever F, Fig. 1, on a post 9, a semaphore y on a post 7, and a double electric switch 6 on a post 4, to be actuated by a passing train. The semaphore arm y, Fig. 2, normally rests in the horizontal " danger " position by its own weight and is raised into the " safety " position when the core v is attracted into an energized solenoid p, after a locking-lever r has been withdrawn against the action of a spring s from a notch v<3> by energizing either of two electromagnets H, a. When the electromagnet a is energized, an armature d is raised against the action of a spring e by pole-pieces b, thus closing spring contacts c and releasing the locking-lever through a link t. The latch f of a spring is withdrawn from the armature d, in the position shown, by a weighted lever k engaging a slot g in the spring. Spring contacts m are closed by a tappet l on the solenoid rod in the danger position and contacts n are closed by a tappet o in the safety position. By way of example, a train may be assumed to enter the left-hand section, Fig. 1, from the right, the left-hand signal apparatus being at " safety," so that the contacts m on the signal post 7 are open, and the circuit which causes lowering of the trip-arm F remains open, thus allowing the train to pass the trip F. The train then actuates a switch S to close contacts 6 and complete a circuit from a battery 11 through a wire pp, the magnet H, and wires qq, rr. The energized magnet H then withdraws the locking-lever r from the core v, allowing the signal arm y to rise to " danger " by gravity. Contacts m are thus closed by the tappet l partially completing a second circuit through the trip-magnet 12, so that, if a second train enters the occupied left-hand section, the first wheel 3 finally completes this circuit through the trip-magnet 12, which allows the trip arm to fall to the danger position, and stop the train. The first train entering the unoccupied left-hand block section also completes a circuit at the left-hand contacts 5 of the double switch S from the battery 11<a> in the preceding block through a wire ss, the magnet aa, the wire tt, and the line-wire v<2>v<2>, and back by the line-wire rr from the contacts 5. The energized magnet aa raises its armature d<a>, closing the contacts c<a> and switching the magnet aa out of circuit and the solenoid p<a> into circuit, which thus raises the signal yy to "safety." The trip-arm when lowered to "danger" actuates a lever, which opens a valve in a tube connected with a drain-pipe, to apply the brakes, or it may actuate the throttle valve. The double switch S may be actuated by a drawbridge, or by a movable part of a track switch, which are thereby included in the signalling-system.