Patent GB-251231-A (GB)
Title: Safety device for automatically stopping trains
IPC: B61L3/04
Filed: 1925-12-11
Abstract: 251,231. Fischer, O. April 24, 1925, [Convention date]. Track apparatus actuating signals on, and for stopping trains. -In means for automatically stopping trains or giving warning to the driver by an abutment on the track, adapted, when in " danger " position, to strike a frangible traincarried device, such as a glass tube &c., or a valveoperating arm, the train-carried device, not shown, is mounted in a pivoted frame normally occupying an operative position, but swung about the pivot to inoperative position by a brake rod, so that the tube is not struck by the abutment and automatic braking is avoided if the brakes have already been applied. The track abutment 1 is adapted to be swung into operative or inoperative position in conjunction with operation of the usual semaphore signal (shown dotted in Fig. 5, which is a linkwork diagram), and is locked against improper movement in each of these positions. The abutment is released by a train-operated treadle, not shown, just before being struck by the train device, and is moved into inoperative position after striking the glass tube &c. by an inclined surface on the train. Means are also provided for moving the abutment independently of the signal and a locking device is described to prevent operation of the signal by force applied to the abutment. The abutment 1 is mounted on a shaft 44 which also carries an arm 23. An arm 24 pivotally mounted on the shaft carries another pivotally connected arm 26 which is adapted to be moved in conjunction with the usual track signal by a rod 27. Arms 24, 26 are urged towards one another by a spring 34, a stop 35 on arm 24 serving to keep the arms apart, as shown. The arms 24, 26 are also normally connected by a pawl 28. Arms 23, 24 are connected by toggle links 30, 31 normally retained in the relative position shown by a detent 32. With the signal at danger, abutment 1 projects into the path of the train-carried device and is held bv rod 27 and the above-described connections. The train operates a treadle device, not shown, just before reaching the abutment, and through suitable linkwork causes the depression of an arm 83 and collar 84, Fig. 15, the collar operating a lever 85 with flexible connection 33 to release the pawl 28. The abutment 1 is then held by spring 34. The frangible device &c. on the train then strikes the abutment and is fractured, applying the brakes. An inclined surface on the train then rotates the abutment in clockwise direction, Fig. 5. to inoperative position, where it is retained by a catch 9 engaging arm 23. The initial movement first releases the links 30, 31 from detent 32, the links 30, 31, and the abutment thereafter moving freely, until towards completion of the movement, which is retarded by a weight 13 connected to arm 23 bv a normally slack chain &c. 36. Weight 13 is suspended on a normally vertical arm, so that, as the arm is moved from the vertical position, the weight acts with increasing leverage. When the signal is subsequently moved to the " clear " position, arm 27 moves to the left, and arms 24, 26 are moved in clockwise direction, the treadle-operated linkwork, not shown, being moved by a sliding bar 55 and crank 60, Fig. 15, to raise the treadle and allow pawl 28 to re-engage. A stop 43 engaging a projection 31<b> on a link 31 returns links 30, 31 into engagement with detent 32, and a cam 42 on arm 24 releases catch 9, so that, when the signal is returned to danger, the parts are returned to the position shown in Fig. 5. To prevent the signal from being moved otherwise than by the proper operating mechanism, the bar 27 is connected to plates sliding in guides 46 and carrying a rocking anchor-member 50 adapted to engage one end or the other of the plate 46, the proper operation of the device being effected through a link 48 attached to member 50. The initial movement of link 48 rocks and releases member 50, further movement moving rod 27, and finally rocking member 50 to engage the other end of plates 46. To allow the abutent to be operated independently of the signal, link 48 is moved by a member 49 pivotally connected to a signal operating rod 94 and to an independently operable sliding member 92 moved by rotating a crank 90 through 180". Normally, member 92 is stationary, and member 49 is moved about pivot 93 by rod 94. For independent operation of the abutment, rod 94 remains stationary, and member 49 is moved about pivot 95 by member 92.