GB203164A - Improvements in or relating to railway signalling systems - Google Patents

Abstract

203,164. Automatic Telephone Manufacturing Co., Ltd., and Hudd, A. E. Aug. 16, 1922. Track apparatus for stopping trains.-Pulsating or other composite currents are supplied from fixed track ramps through a collecting shoe, which serves also to remove mechanical restraints from the brake valves, to two electromagnetic restraining means which are responsive to different characteristics of the composite current. Fig. 1 shows the traincarried apparatus which comprises a sliding shoe 1 having a collar 3 coacting with collars on the spring pressed rods 6, 7 to remove these from the bell-crank levers 13, 14 which operate the brake valves 10, 11. The bell-cranks 13, 14 carry the armatures of an alternating current electromagnet 12 and a polarized electromagnet 15. The winding of magnet 12 is in the secondary circuit of a transformer 42, the primary of which, in series with the winding 15, is energized from the track ramps through the shoe 1. Fig. 2 shows the circuits to a home signal ramp 53 and a distant signal ramp 36. At a distant signal the vibrator generator 40 is put in action by a train on an insulated rail section 35, and negative pulsating current is supplied, if the signal is at danger, from the battery 46 to the ramp 36 and the train apparatus. Magnet 12 is energized and holds the valve 10 closed. Magnet 15 releases its armature and the valve 11 is opened by the air pressure and the audible signal 17 is sounded and a service application of the brakes is made. If the distant and home signals are clear, positive pulsating current of greater magnitude is supplied from battery 45 over the lever contacts 44, home signal contacts 43 and distant signal contacts 41, this current preventing the opening of the brake valves and sounding the bell 47. At the home signal, a weak positive pulsating current from part of battery 45 over the vibrator 51 and switch 50 is received if the signal is clear, which restrains the brakes but does not operate the bell 47. If the signal is at danger, no current is received and both valves 10, 11 are opened. The valves 10, 11 may be closed by Bowden or similar mechanism. A retarding device, such as a screw movement 62, is fitted on the emergency brake valve resetting mechanism to ensure the prolonged application of the brake sufficient to stop the train. The resetting mechanisms simultaneously open valves 24, 34 while they are in use thereby ensuring their replacement in order to release the brakes. The shoe 1 is hollow and the cavity is connected to the train pipe by ports 29, a chamber formed by flexible diaphragms 27, 28, and conduit 26. Breakage of the shoe, therefore, causes application of the brakes. The shoe is held in its raised position by detents 21 until the valve is re-set. A collar and pin on the valve stem serve to move the detents into and out of operative position.