GB363405A - An improved rail contact for use in connection with railway signalling - Google Patents

Abstract

363,405. Treadle contact apparatus for railway signalling. SIEMENS & GENERAL ELECTRIC RAILWAY SIGNAL CO., Ltd., Caxton House, Westminster. -(Parsons, J; Rosario, Santa Fe, Argentine). Sept. 18, 1930, No. 27899. [Class 105.] A pivoted rail treadle is adapted to actuate sets of electrical contacts in succession in an order of actuation dependent on the direction of movement of the train. As shown in Fig. 1, a treadle 10 with a curved surface is pivoted to a plunger 11, 20 of a spring dashpot 19 and is biased by a spring 23 to the position shown in which electrical contacts 27, 28 are closed; electrical contact members 29, 30 provided on the dashpot plunger 11, 20 and on a guide 15 therefor are open. A train moving from right to left will first tilt the treadle 10 to open the contacts 27, 28 and shortly afterwards will depress the treadle and plunger to close the contacts 29, 30 and will also restore the contacts 27, 28 to the closed position; a train moving from left to right will not however open the contacts 27, 28. Fig. 4 shows diagrammatically the application of the treadle device 10, 19 to the control of a level crossing signal. The two pairs of contacts 27, 28 and 29, 30 of the treadle device 10, 19 are placed in parallel in a circuit to a signal controlling relay 35, 36 and as during the passage of a train in one direction the two sets of contacts are for a short time both open the magnet 35 will be de-energized and the second magnet 36 can then move the relay armature over to close the contacts 38, 39 for giving the signal. When the train reaches the level crossing it actuates a vibratory sleeper contact 41 which momentarily de-energizes the second magnet 36 of the relay so that the armature is restored to normal. A train going away from the crossing actuates the treadle device 10 but in the manner that the contacts 27, 28 remain closed and so the crossing signal is not actuated.