Patent GB-191115280-A (GB)
Title: Improvements in and relating to Railway Cab-signalling.
Inventor: MARTIN RICHARD HARINGTON
IPC: B61L3/00
Filed: 1911-06-30
Granted: 1912-06-27
Abstract: 15,280. Martin, R. H. June 30. Track apparatus actuating signals on trains; miniature signals.-A danger signal is produced periodically by the movement of the engine, and is adapted to be cancelled by a 'clear' signal received from the track, improved indicating-means being provided in the cab. A cam C<1> is driven from the train wheels to rotate once during the movement of the engine over a distance slightly greater than that between signals. The cam supports the roller of a lever C<2> which carries a guided rod C<10> held on one side by a spring C<18> and on the other by an electro-magnet C<19>, in circuit with a battery E<1> and a contact S adapted to be closed from the track contact when at ' line clear.' The rod C<10> is adapted to engage either side of a casting C" to place the signal C<21> at danger or clear. The lever C<2>, when raised, closes a contact C<37> in the circuit of a motor M. When a ' clear ' track contact is passed, a spring-held engine lever is operated and held in a catch on the armature of an electro-magnet. In its operated position, the lever closes the contact S to energize the magnet C<19> to attract the rod C<10>. The armature of the motor M is on the shaft of the cam C', which is driven by pawl and ratchet-wheel from the wheel, so that when the contact S is closed, the motor speeds up the cam until the lever C<2> falls to break its circuit. The semaphore is then put to safety by the rod C<10>, and is held there until the next operation. If the track contact is passed at danger, no signal is given until the cam completes its ordinary rotation. The sections may, however, be extended, and the track contacts arranged to give both ' danger ' and ' clear ' signals, as described, for instance, in Specification 15,281/11, the danger contact then closing the motor circuit only. The cam C' in its rotation closes a releasing-circuit for the engine contact, and a testing-circuit. Instead of a motor M, a second gear train may be clutched in to accelerate the cam C<1>, or the armature of a directcurrent four - pole motor without commutator may be directly connected thereto. The semaphore arm C<21> may be operated as shown in Fig. 6, in which a lever C<24> pivoted to the rod C<10> is controlled bv an anchor C<25> controlled by a spring C<29> and a magnet C<30> to lock one end or the other of the lever C<24> so that operation of the lever C<2> causes the other end to rise. The ends are connected by links C<31>, C<32> with pins working in slots C<33>, C<34> in the arm. The anchor may be pivoted above the lever C<24> and controlled by a weight instead of a spring. For operating the arm pneumatically it is connected to a piston P<2>, Fig. 9, in a cylinder P' communicating with a vacuum (or pressure) reservoir through a pipe P<14> and an electro-pneumatic valve P<5>, and with atmosphere through valves P<7>, P<8>. The valves P<5>, P<7> are connected and operated by the armature P<9> of a magnet P<10>, while a spring P<12> holds the valve P<5> slightly open when the valve P<8> is closed. The valve P<8> is connected to the lever C<2>, and is opened when the lever falls. When a track device is passed at safety, the magnet P<10> is energized, thereby closing the valve P<7> and opening the valve P<5>, The piston P<2> is moved, by the vacuum produced, to operate the arm C<21> despite the subsequent opening of the valve P<8>. The valve P<8> is then closed by the continued rotation of the cam, but if a contact is passed at danger, the valve P<8> again opens, and as the valve P<5> is now closed, the arm is returned to danger. A handle may be pulled across the instrument when the cab signal is out of action, and held by a catch which is electrically released on passing an operative contact, the movement of the handle switching out the magnet C<19> and switching in the releasing-magnet. When the semaphore arm is pneumatically operated, the handle on the shaft H<2> moves a two-way cock P<6> to connect a cylinder H<22> and piston H<23>, so that on receipt of a line-clear signal, the piston H<23> returns the hand-lever. The hand-lever may also hold the arm C<21> and lever C<2> raised, and, when the apparatus is combined with a positionindicator as described in Specification 15,282/11, may also pull out the toggle to prevent that indicator from being operated.