Patent GB-189823311-A (GB)
Title: Improvements in Apparatus for Ensuring Safety on Single Lines of Railway.
Inventor: TYER EDWARD
Filed: 1898-11-05
Granted: 1899-10-14
Abstract: 23,311. Tyer, E. Nov. 5. Controlling traffic on railways, staff and ticket systems for.-Relates to tablet or staff apparatus of the kind described in Specifications No. 1262, A.D. 1878, No. 42, A.D. 1888, No. 5928, A.D. 1890, Nos. 1904 and 18,603, A.D. 1891, No. 2798, A.D. 1892, No. 12,144, A.D. 1893, No. 14,001, A.D. 1894, and No. 21,831, A.D. 1895, for controlling traffic on single lines. In the present invention, the apparatus can be arranged either for absolute or permissive working. For absolute working, in which a tablet issued from one end of a section must be returned to the instrument at the other or the same end before another tablet can be issued, the issuing slide b is controlled from the other end of the section through electromagnets which operate the locking-pawls f, g. To issue a tablet at one end, say A, the operator at that end,' on receiving assent from the other end, say B, depresses his plunger n, so energizing the electromagnet of the pawl g in B's instrument, releasing the pawl, and permitting B to withdraw his slide b about half-way. This withdrawal reverses the line contacts, so that, on B depressing his plunger n, the pawl f in A's instrument is released, and also raises the pawl g, allowing A to withdraw a tablet. Both slides now remain locked until the tablet is returned to one of the instruments through its slide d. The tablet, entering the shoot i to the receptacle a, tilts the rocking lever j, and raises the pawl g, so permitting the slide b to be pushed in, after which the operator at the other end depresses his plunger n to unlock his slide b and then returns the latter. For permissive working, in which a number of tablets can be issued in succession from one end of a section, an additional tablet receptacle c, normally closed by a transverse slide e, is mounted on the top of the instrument, a lever connected to the rod m resting on the top of the tablets. The apparatus is set by the key lock l, and the slide e withdrawn. The operator at the other end, say A, can withdraw a tablet in the ordinary way. To obtain a second tablet, he actuates his plunger o, which, through the electromagnet p, raises the pawl q and releases B's slide d. B, by pushing in this slide, transfers a tablet from c to a, and can then issue another tablet to A. When a tablet is transferred from c, the rod m falls and locks the bolt l, so that it cannot be unlocked nor the key withdrawn. Each tablet, on reaching B, is inserted in the receptacle c, the lever t being operated to release the pawl u, and to raise the tablets in the receptacle, to permit the withdrawal and insertion of the slide d. This operation permits the issue of another tablet to A, by a repetition of the operations. When B's receptacle c is filled, he can push in the slide e and unlock and withdraw his key, so restoring the the conditions for absolute working. An indicator s, bearing indications such as 'Section 'clear,' Train approaching,' and Train on line,' is operated by the projection r on the slide b.