Patent GB-536609-A (GB)
Title: Improved method of operating power signalling for railways and the like
IPC: B61L19/14
Filed: 1939-10-13
Abstract: 536,609. Railway signalling systems. DELL, R., LONDON PASSENGER TRANSPORT BOARD, MORRIS, F. J. C. and BRAY. D. A. [Representatives of EVERY, W. S.] Oct. 13, 1939, No. 27802. [Class 105] In a railway signalling system having electrically operated signals and points controlled by levers mounted in an interlocking frame with. the usual control through track-circuit relays, the interlock between the levers preventing conflicting operation, subsidiary cabins are provided, each operating signals and points in its vicinity, the levers of the interlocking frame in each cabin being provided with operating means under electrical control from a central control cabin, so that posting a signalman to each subsidiary cabin is avoided. If required, however, the levers at a subsidiary cabin may be brought under direct manual control. As described, the levers are operated pneumatically under electric control. Fig. 1 shows the arrangement at a subsidiary cabin of a bank of levers 11 and horizontally movable interlocking bars 19 co-operating in the usual way with vertical bars, not shown. Each lever, mounted on a spindle 13, has a bevelled tooth sector 14 meshing with a sector 15 on vertical shaft 16, which is of square section except at its end bearing portions, and carries a toothed sector 18 meshing with a rack 71 on corresponding bar 19 so that lever and bar operate simultaneously. Normally, however, shaft 16 is operated by compressed air delivered to one or other of a pair of cylinders 51, Fig. 1, through ducts 37, 38 under control of valves 39 of known type electrically controlled from the central cabin. Fluid is selectively supplied to the working space in one cylinder, the working space in the other being simultaneously vented. Each piston 55 has a rod 57 carrying at its external end an adjustable abutment member 64, with lock nut 65, bearing on a roller 66 carried at the end of an oscillating arm 68 clamped on shaft 16, together with sector 18. Shaft 16 may thus be rocked in either direction. Movement of lever 11 is communicated through sliding rod 31 and links 30, 34 to an arm 26 having bevelled tooth sector 27 meshing with toothed sector 28 on the end of a vertical shaft 22 which operated contacts 23 directly controlling supply of power, over terminals 24, for operation of the points or signals. Backlocking and track-locking to prevent lever movement after track circuits associated with the signals or points are occupied by trains, is controlled by means of armatures 75 depressed by springs and raised when the corresponding magnet 74 is energized. Each spring surrounds a vertically sliding rod 76 connected to the corresponding armature and having a transverse member 77 at its upper end of dove-tail section to co-operate with the undercut end 80 of a notch in rod 31, this formation preventing the lock from being " jumped " out of engagement. Normally, the parts 77, 80 are held out of contact by a second lock comprising a pair of toggle levers 81, 82 pivoted at one end 84 to a fixed bracket 85 and carrying at the other end a roller 86 co-operating with the undercut end 89 of a notch in rod 31. In the locking position, Fig. 2, the levers rest, under gravity, on a stop 88 with the central pivot 83 slightly below dead-centre, so that the levers act as a rigid strut to prevent movement of rod 31 to the right. When rod 76 is raised to release lock 77, 80, a projection 90 above part 77 knocks the levers up so that they can collapse and allow movement of rod 31. The pair of locking arrangements shown in Fig. 1 are oppositely disposed, the right-hand toggle mechanism having been collapsed upwards to allow movement of rod 31 to the left, where it is retained by the left-hand arrangement. As described, signals and points are controlled by individual levers, but the invention may be applied to route-control systems in which the control effects initiation of a series of operations following automatically to set up the complete route. Direct manual control of the levers at a subsidiary cabin may be assumed by cutting off the supply of compressed air, so that pistons 55 remain in their innermost positions, allowing free movement of shaft 16.