Patent GB-520580-A (GB)
Title: Improvements in or relating to railway signal and/or points control equipment
IPC: B61L19/06
Filed: 1938-10-07
Abstract: 520,580. Route setting apparatus for railways. STANDARD TELEPHONES & CABLES, Ltd., GRIFFITHS, J. B., BROWN, A., and MARSHALL, T. A. Oct. 7, 1938, No. 29134. Addition to 496,495. [Class 105] A railway signal and points control equipment as claimed in the parent Specification is modified to provide a complete lock-out preventing the simultaneous operation of any two multiposition switches, whether in a position to set up conflicting routes or not. The arrangement also reduces the number of relays and relay contacts associated with each switch. Specification 516,800 is referred to. The magnets 1RC...5RC which, when energized in response to manually operated selective means, cause engagement of their respective sequenceswitch driving clutches with a common drive are arranged in parallel across a pair of feed lines with their connections in reverse order with respect to the terminals of these lines, and each has a pair of contacts 1, 2 arranged respectively in the positive and negative feed lines. These contacts are opened when the corresponding magnet is energized, contact 1 of any magnet energized, for example, 3RC, cutting the positive feed to all magnets situated to the right of magnet 3RC and contact 2 the negative feed to all magnets situated to the left. In the circuit diagram given, which shows, with modified convention, the control circuits of one of the five sequence switches described in the parent case, A represents the master control cam of the sequence switch cut in all route setting positions, L shows a cam making contact only in the " home " position, and F the cam of sequence switch 3 making contact in all positions except 1 or 3. Cams D, E of sequence switch 2 are adjacent copper cams connected by metal rivets and cutting their appropriate circuits in positions 15, 16 and 2, 4 respectively. Similarly the pairs of cams B, C and D, E of sequence switch 1 are riveted together, and are connected, together with F, on the sequence switch rotor without external wiring. The wipers coacting with cam C make contact continuously from home position to position 6, and from home position to position 5, respectively. Assuming that the signalman reverses panel switch 5 to set up route 5, if sequence switch 1 is in home position and sequence switches 2, 3, 4 are not standing in positions corresponding to conflicting routes, relay 1R is energized, and this energizes clutch magnet 1RC for sequence switch 1 provided that no other clutch magnet is energized. The switch 1 then rotates from home position. Circuit of relay 1R is broken at cam B, but the relay remains energized over cam A until the switch reaches the position allotted to route 5, whereupon relay 1R and clutch magnet 1RC are de-energized and the switch comes to rest. Relay 1PR is then operated over contacts 1RC3 and cam 1H, and in conjunction with sequence switch 1 in position 1 sets the necessary points and clears the signal for route 5, provided that the interlocking sequence switch and panel control key circuits remain intact. Original circuit of relay 1R is now broken by cam L and the sequence switch cam can only be driven "home" by contacts 1YR2 after proving route 5 safe to be restored to normal. Operation of relay 1YR is as described in the parent Specification.