Patent GB-358680-A (GB)
IPC: B61L3/12
Filed: 1930-09-11
Abstract: 358,680. Automatic train control apparatus. LORENZ AKT.-GES., C., 1, Lorenzweg, Tempelhof, Berlin. Sept. 11, 1930, No. 27189. Convention date, Sept. 11, 1929. [Class 105.] In an electric automatic train control device, provided with acknowledging keys to allow " caution " and, on special occasions, " danger " signals to be passed without effect on the brakes or other train apparatus, the keys incorporate time switches to compel correct operation of the appropriate key within a predetermined time before passing a " caution " or " danger signal; a brake-releasing key provided for use after a compulsory brake application also has a time switch to delay release until the train has stopped. Each key has an upper part which returns to normal as soon as released and a lower part which only returns a given time after rebease of the key ; each part operates electrical contacts, and the acknowledging circuits are only completed when the two parts of the key are in opposite positions. The track apparatus comprises a tuned electromagnet at each signal, energized when the signal is at " caution " or "danger, different frequencies being employed for the two indications. The receiving apparatus on the train comprises two circuits, supplied by alternators M1, M2, tuned to be affected by the track magnets at " caution " and " danger " signals respectively. The circuits controlling the apparatus on the train are supplied by a direct-current generator C through a switch S which may be coupled to the stop-cock of the train pipe. The apparatus includes two relays having armatures wrl, wr2, controlled by alternating current windings WRl, WR2 in the receiving circuits and direct current windings Ru1, Ru2 in the control circuits ; each winding is only strong enough to move the armature when the current in the other winding is weakened. On passing a " caution signal the current in the winding WRl is momentarily reduced and the armature wr1 moves over to extinguish a white lamp Lw and light a red lamp Lr, at the same time operating a recorder Zl and an audible signal (or brake valve) H. If the key Wk has been pressed and released within the prescribed interval of time before passing the signal, however, so that its lower contact is in the lower position while the upper one has returned to the position shown, the recorder and audible signal are not operated, and the winding Rul of the relay is short-circuited, the contact x being closed when the relay X is de-energized by the armature wrl ; the winding WR1 therefore immediately returns the armature to its normal position. If the key is held down, the effect is the same as if it is not operated. On passing a " danger " signal, the winding WR2 is weakened, and the armature wr2 moves over to de-energize the brake magnet BM and apply the brakes and to actuate a recorder Z2 and light a red lamp Lr. This action can be prevented by correct operation of the key Bf, which is only for use on special occasions, to short-circuit the winding Ru2, so that the armature wr2 is not operated ; the key Bf always actuates a recorder Z3. After a compulsory brake application, which would normally occur at a "danger" signal, the brakes can be released by use of the key LT, of which the contacts are of the " make-beforebreak " type. Pressing of,this key after the armature wr2 has been operated energizes a relay Y to close its contacts yl, y2 to maintain this relay energized until both parts of the key returns to normal and then to short-circuit the winding Ru2 momentarily to restore the armature wr2 and release the brakes before contacts yl, y2 are opened by de-energization of relay Y. The time lag of the key LT is sufficient for the train to stop before release of the brakes. The key LT and relay Y may be replaced by an ordinary switch, in parallel with the winding Ru2, placed so as to be inaccessible until the train has stopped. If the key is operated and released before the armature wr2 has moved to the right, relay Y is not energized, and no releasing action follows. Relays Cl, C2 in the respective control circuits control contacts cl, c2 in the brake magnet circuit, so that the brakes are applied if either of the control circuits is interrupted, or they may simply control indicators.