Patent GB-190113649-A (GB)
Title: Improvements in Apparatus for Ensuring Safety of Traffic on Single Lines of Railway.
Inventor: TYER EDWARD
Filed: 1901-07-04
Granted: 1902-05-29
Abstract: 13,649. Tyer, E. July 4. Controlling traffic on railways, staff and ticket systems for ; signalling-instruments.-Relates to apparatus of the kind described in Specifications No. 5928, A.D. 1890, and No. 1904, A.D. 1891, for controlling the issue of tablets on single lines, on the "absolute" system which permits only one tablet to be out on a section. In the present invention, the apparatus described in Specification No. 1904, A.D. 1891, is modified for " permissive" " working, so that a number of trains can be sent in succession from one station to another, but a train cannot be sent in the opposite direction until all the tablets issued from the one station have been received and inserted in the instrument at the other station. In the instrument, the magazine disc D for the tablets T<2> is operated by the spindle T<1> in the usual way, but is made separate from the multiple cam or commutating-disc C. The spindle T' is made hollow to receive the rod b, which carries a boss d and can be depressed against the action of the spring c, the discs D, C being connected, in the position for " absolute" working, by a feather on the boss d engaging in corresponding slots in the disc. The disc C, like the disc D, is provided with two sets of ratchet teeth facing in opposite directions, an additional pawl and electromagnet being provided to control the movement of the disc C in one direction. The slide e is provided with a recess g to receive a tablet, and is fitted with a slide i to which is pivoted a latch h, adapted in the position shown in Fig. 1 to prevent the withdrawal of the slide e. The slide i is guided in a slot in the slide e, and is urged to the right by springs f. In operation, when an operator A desires to send a train to B's station, A signals to B for permission, thereby permitting B to withdraw a tablet. B then slightly depresses his rod b, to disengage the latch h, draws out the slide e, places the tablet in the recess g, and pushes in the slide, the tablet in the return movement of the slide pushing the slide i into the position shown in Fig. 4. B then pushes the rod b fully down, its lower end passing through holes in the slide i, in a cross-piece on the slide e, and in the base-plate, as shown in Fig. 4, so locking the slide e in with the tablet, this movement disengaging the feather on the boss d from the disc D, and leaving the disc C free to be turned independently. A now sends a current through the additional electromagnet in B's instrument, releasing the disc C, which is turned by B through the space of one tooth, so that it coincides electrically with A's instrument, to enable B to give A permission to issue his first tablet. The movement of the disc C displaces the slot in the disc C out of coincidence with the slot in the disc D, so that the feather on the boss d prevents the rod b from rising, thus preventing the issue of a tablet from B's instrument. In dispatching other trains in the same direction, A calls to B for permission to issue each additional tablet required, and in so doing permits B to turn his disc C one division further, to make the electrical connections necessary for each issue. When the desired number of trains have been dispatched, A advises B by code or telephone, and as the trains arrive B inserts the tablets into the disc D of his instrument. When all the tablets have been inserted, the slot in the disc D is again in coincidence with the slot in the disc C, and the rod b is then forced up by the spring c to connect the discs C, D, this movement also unlocking the slide e, enabling the tablet in it to be withdrawn and returned to the instrument, to restore both apparatus and their connections to the normal condition.