Patent GB-190126744-A (GB)
Title: Improvements in and relating to Signalling on Electric Traction Systems.
Inventor: JONES THOMAS HARISON
Filed: 1901-12-31
Granted: 1902-12-24
Abstract: 26,744. Jones, T. H. Dec. 31. Electric railways and tramways, signalling on; semaphore &c. signals; controlling and locking signals ; interlocking; signalling &c. between trains.- Relates to electric signalling on electric traction systems, more particularly on interlacing double tracks, or single tracks, &c., of electric railways and tramways, on which two cars cannot, or are not desired to, pass each other. Fig. 1 shows the operating mechanism of the signal employed, and Fig. 2 the locking mechanism therefor. The pivot of the semaphore arm a carries an iron armature c provided with insulated windings d, and is surrounded by a ring e of cast iron or other magnetic material. This ring forms part of the casing, and is provided with pole-pieces f, also having suitable windings. The signal arm is normally in the horizontal or ' danger' position, and is lowered to 'line clear' by a current through the coils on the pole pieces. The locking mechanism consists of a core h adapted to engage under the arm i on the pivot of the semaphore. The core h is actuated to lock the semaphore by one of the solenoids k, Fig. 2, and in the opposite direction, to release the semaphore, by the other solenoid, the two solenoids being connected to separate leads n and a common return u. A tail-piece l<1> on the arm i prevents the signal from being locked in any other position than full up. Fig. 3 shows the application of the signals to two tracks, having an intermediate single track section common to both, and a double trolley fed from one end. The conductors for each track are each divided into insulated sections 1, 2, 3, 4, 5. The leads s of the signal t at one end of the section are connected to the sections 2, 3 of one conductor, and the leads n' of the locking coils k<1>, k<2> are connected to the sections 3. 4 of the same conductor, the corresponding sections of the other conductor being similarly connected to the locking coils k<1> of the signal t and to the signal t' at the other end of the single track. The return leads u, u<1> of the locking coils are connected to an auxiliary conductor r. When a car approaches the single track, say in the direction of of the arrow, and enters on the section 2, it draws its motive current through the signal t and the locking coil k<1> at the other end of the section, lowering its signal t and locking the signal t' against a car approaching in the opposite direction. When the car enters section 3, the signal t is cut out and returns to ' danger,' while, on the car entering section 4, the coil k<1> is cut out and the coil k<2> is cut in to release the signal t'. A solenoid v opposing the locking coil k<1> is connected in series with the signal t', so that, in case of two cars approaching simultaneously, one of them will be given the preference. Instead of the solenoid v, a tooth may be provided on the tail-piece l<1> to engage with the stop h and hold the signal arm at " half-cock." In case of junctions at the ends of a protected section, two or more signals may be provided at each end of the section, each signal being arranged in series with the locking coils of all the other signals. The auxiliary conductor r can be dispensed with in case of a double trolley fed from both ends, and having a feeder near enough to be tapped direct. For a double trolley fed from both ends, but not having a feeder conveniently accessible, and for a double trolley merging into one at the single track section and fed from one end, the auxiliary conductor is employed.