GB224224A - Improvements relating to safety devices for railway and like crossings - Google Patents

Abstract

224,224. Holm, H. T., and Westfelt, A. U. Nov. 2, 1923, [Convention dale]. Operating barriers by treadles and the like.- Railway barriers or signals or both at road-crossings are actuated to the roadclear position by gravity and are reversed by expansion under control oi an electromagnetically operated valve, of air which is compressed in a reservoir by a passing train. The barrier 2 normally occupies the roadclear position under the action of the counterweight 4, and the piston 14 is fully Lome in the cylinder 15, to which position it was moved by the last train. A train approaching the crossing completes the circuit to the the solenoid 25, the armature of which trips the valve lever 23 which is held tripped by the catch 28. Liquid is then forced by the compressed air in the reservoir 17 into the, cylinder 15 and the piston 14 is moved outwards, and through the lever 8 and rope 6 the barrier is closed or the signal set at danger. A stop 32 on the rope releases the catch 28. As the train passes the crossing, a ramp 11 meets the roller 10 and moves the piston 14 inwards thereby recompressing the air in the reservoir 17 through a non-return valve, and at the same time releases the rope 6 to allow the counterweight 4 to restore the barrier or signal.