Patent GB-190107966-A (GB)
Title: Improvements in or relating to Electro-pneumatic Controlling Systems.
Inventor: HILL ERNEST ROWLAND
Filed: 1901-04-18
Granted: 1902-02-27
Abstract: 7966. Hill, E. R. Sept. 20, A.D. 1900, [date applied for under Sec. 103 of Patents &c. Act, A.D. 1883]. Cut-outs ; switches.-Relates to improvements on electro-pneumatic control systems for electricallypropelled railway vehicles such as are described in Specifications No. 4327, A.D. 1899, and No. 11,835, A.D. 1900. The improvements comprise means whereby failure of power, resulting in reduction of speed, will open the motor circuit ; means for stopping each controller when the motors are in series and in parallel without resistances ; and devices for interlocking the controller, reversing- switch, and circuit-breaker so that the latter cannot be closed until the reversing-switch is in one or other operative position and the controller is off, and so that the controller cannot be operated when the circuit-breaker is open, and also for returning the controller when the circuit-breaker opens. A deficiency of current in the motor circuit, shown as one field coil 20 in Fig. 2, allows the coil 2 to release a valve 6 which opens an adjustable leak-off from the cylinder 10 so that the spring piston breaks the circuit to the controller-releasing magnet 16 at the switch 15. This safety device may be rendered inoperative during the first steps of the controller by shortcircuiting the switch 15 through a second switch 22, which is opened by the descent of its bridgepiece when a recessed part of the piston-rod 28 is brought beneath it by air pressure from the controller-releasing cylinder. To stop the controller in the full series or multiple positions, the ratchetwheel 30, Fig. 3, on the controller drum shaft has two stops 32, 33 of different lengths which limit the rise of the piston 37 at those points under air pressure admitted through the pipe 35 from the controller-operating cylinder. The piston carries a bridge-piece working over three contacts 41, 42, 43, of which 43 is shorter than the others. When the piston cannot rise, the circuit of the magnet of the exhaust valve is not broken, and the controller stops. To continue its movement after the series position, the circuit is broken at the handswitch and transferred to the shorter contact 43. A valve 64, Fig. 5, in the pipe 67 connecting the operating-cylinders 60 of the reversing-switch with the cylinder 68, Fig. 7, of the circuit-breaker, prevents air from passing to close the latter unless the reversing-switch is home in either direction. The interlocking of the circuit-breaker and controller is effected by a switch similar to the switch 22 in Fig. 2, which is caused to complete the circuit to the reversing-switch magnets for operating the reversing-switch and circuit-breaker when the controller is in its off position. The same effect may be produced by a valve in the pipe 67 operated by the controller. The circuitbreaker is shown in Fig. 7 with two pistons 78, 85 to throw the handle directly or through the loose piece 83, and the handle is also connected to the switch 92, which is in circuit with the operating- magnets of the controller drum. A general diagram of the connections is given in the Specification.