Patent GB-560989-A (GB)
Title: Improvements in electric signalling interlocking systems
IPC: B61L19/06
Filed: 1942-10-19
Abstract: 560,989. Railway signals &c. CROOK, G. H. Oct. 19, 1942, No. 14588. [Class 105] The dual purpose of controlling remote railway signals, points or other apparatus and of locking levers in an interlocking machine is effected by a manually operated instrument comprising electric switch contacts closing different circuits in different positions of an operating handle movement of which is controlled by an electromagnetic lock releasable only under predetermined conditions, the instrument controlling circuit arrangements appropriate to the particular operations to be effected. Fig. 1 shows an instrument in front and side views comprising spindle S carrying contacts m<1> ... m<4> co-operating with fixed contact blades C<1> ... C<5>, and rotatable by a handle H (or in some cases by a key serving as a handle and removable, in a predetermined position of the spindle, for use as a key). The spindle carries a disc C having peripheral ports P co-operating with a locking member L carried by the armature A of an electromagnet M. Press-button contact closers, such as p<1> and detector contacts d controlled by armature A for proving the condition of lock L, are also provided. As shown, spindle S has three circuit-closing positions, but this number may be varied to suit requirements. The ports P may also be varied to suit requirements. As shown, the spindle can only be moved between positions 1 and 2 when the lock is released, but can be freely moved between positions 2 and 3. If required, the ports may be shaped to allow free movement in one direction but prevent movement in the other direction without lock release. Fig. 3 shows the invention applied to a ground lever GL having a key-lock KL releasable by a key K normally retained in the lefthand or key instrument but removable therefrom under remote control of the right-hand or control instrument over line LC, this instrument also controlling the lock LM of an interlocking lever IL. As shown, both levers are locked and both instruments are locked in No. 1 position. If press-button p<1> be operated, magnet M<1> is energized from battery bl over a circuit including contacts c<4>, c<5> and detector contacts d<2> of magnet M<2>. Lock LM is thus released and lever IL may be operated. Whilst lock LM is released contacts d<1> included in the circuit of magnet M<2> are opened and are held open when lever IL is moved from the position shown, so that the control instrument cannot be operated unless lever IL is locked in the position shown. If, however, press-button P<2> be operated when lever IL is so looked, magnet M<2> is energized from battery b<1> over a circuit including contacts d<1>, c<1>, c<2> releasing the instrument for operation by handle H to No. 3 position. This breaks the circuit of magnet M<1> at contacts c<4>, c5 so that lever IL remains locked whilst the control instrument is moved from the position shown. Current can now pass from battery b<1> over contacts d<2>, c<3>, c<4> to line LC and if the key instrument has been moved to its No. 2 position (no locking against this movement) current passes over contacts c<7>, c<8> through magnet M<3> thus releasing the key instrument for movement to its No. 3 position in which the key K can be removed and used for releasing the lock KL on lever GL for the operation of points or signals. When lever GL is moved, the key K is retained in the lock KL in known manner so that the key instrument cannot be restored until lever GL is restored to the position shown .to release the key. When the key instrument is restored to normal position and press button contact P<3> closed, battery b<2> is connected to line LC over contacts d<3>, c<6>, c<7>. When the control instrument is moved to No. 2 position and press-button P<3> operated, current flows from line LC over contacts c<3>, c<2> through magnet M<2>, releasing the instrument lock to allow restoration of the instrument to the normal position shown. The Specification gives circuit diagrams and describes in detail the use of instruments generally similar to that shown for controlling two or more levers such as IL, or for releasing one at a time any number of key instruments. The Specification also describes two or more instruments having joint control over a key instrument for use, for example, with a cross-over switch affecting two or more lines, the use of instruments locking each other at two cabins to prevent conflicting or opposing movement over the same section of railway between the cabins, the control of junctions or crossings between two cabins by use of control instruments operating in conjunction with electric block telegraph or other block signalling means, and a branch line layout in which the point switch is electrically operated under control of one instrument, two signals are electrically operated each under control of an instrument, and a third signal is mechanically operated by a lever of an interlocking machine, the control thus involving the use in mutually interlocking combination of three instruments similar to those described above, the railsection in which the point switch is situated being insulated and provided with a track relay, the contacts of which are included in the control circuits.