GB770674A - A warning device operating mechanism for association with a rail track - Google Patents

Abstract

770,674. Railway warning signals. STEWARTS & LLOYDS, Ltd. June 13, 1955 [June 16, 1954], No. 17666/54. Class 105. A railway track mechanism operable by the passage of a train for giving an audible or visual signal warning of its approach comprises a base 4 having means such as fixed lugs 6 and detachable lugs 7 adapted to overlap the foot of the rail 5, whereby it may be removably connected at any part of the rail length; a plate 13 displaceably supported on the base as by pivoting about an axle 11 and arranged to be depressed by the flange of a passing wheel; and a shock-absorber, for example, in the form of a buffer spring 22, for transmitting movement of the plate 13 as by a tappet 19 to the operating member 24 of a valve 28 or an electric switch for setting the warning device into operation. The plate 13, as shown, is mounted upon a counterbalanced lever 12 secured to the axle 11 and has its counterweight 14 co-operating with a fixed pedestal 15 to limit the upward movement of the plate 13. An arm 16 keyed to the axle 11 transmits the movement of the plate 13 to the tappet 19, there being lost motion between a plunger 18 working within the tappet 19 and the tappet itself. To control the rate of return of the plate 13 from the depressed position to avoid interrupted signal on the passage of each wheel, a dashpot device 25 with a valve-controlled outlet 27 is connected to an extension 26 of the lever 12. The ends of the plate 13 are inclined downwards in the longitudinal direction to form a lead for the wheel flange. The end part of the base-plate 4 is vertically adjustable by a screw jack 9.