Patent GB-421067-A (GB)
Title: Improvements in and relating to safety apparatus for controlling electric railway locomotives and vehicles
IPC: B60L3/02
Filed: 1933-06-14
Abstract: 421,067. Fluid - pressure brakes. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.- (Assignees of Allgemeine Elektricitõts-Ges.; 2, Friedrich Karl-Ufer, Berlin) June 14, 1933, No. 16997. Convention date, June 15, 1932. [Class 103 (i)] [See also Group XXXI] Safety apparatus of the dead-man handle' type comprising means for breaking the motor circuit and applying the brakes if a switch is released for a period determined by a retarding device, is characterised by the provision of two retarding devices, one operative when a predetermined distance has been travelled after the release of the switch and the other after a predetermined time has elapsed, both devices being controlled by the same safety switch and performing the same safety functions. Thus, if the vehicle is travelling quickly the distance-controlled device comes into action before the other can act, while if the vehicle is travelling slowly the time-controlled device comes into action. In the construction shown in Fig. 1, a distance-controlled device 5 and a time-controlled device 6 are held out of action by a rod 40 as long as one of a number of switch buttons 1 is depressed. When any one of these buttons is depressed a circuit is completed, through a normally-closed switch 2, of a solenoid 3 which raises a double valve 44 to the position shown and admits compressed air from a pipe 45 to a cylinder 42, so that the piston 41 of rod 40 is raised to lift levers 39, 43. When the depressed button is released the solenoid 3 is de-energized, and valve 44 opens to exhaust so that piston 42 falls and allows a roller on lever 39 to rest on a cam 38 driven from a vehicle axle. The lever thus receives an oscillatory motion which acts on ratchet gearing in the device 5 and, after a predetermined distance has been travelled, first causes a switch arm 50 to close the contacts 36 of a buzzer 37 and finally rocks a lever 49 to open a brake valve 48 and break the main motor circuit at 48a. The fall of the lever 39 allows lever 43 to fall and this starts a clockwork or time-controlled device 14 which, after a predetermined time, causes a switch arm 35 to close the contacts 36 of the buzzer 37 and finally closes a switch 7 to complete the circuit of a solenoid 29 which rocks a lever 46 to open the brake valve 48 and break the main motor circuit. If one of the buttons 1 is pressed after the buzzer has sounded, but before the brake valve and main switch are operated, the rod 40 is raised again to lift the levers 39, 43 and the devices 5, 6 are re-set to their normally-inactive condition. In the timecontrolled device shown in Fig. 2, the rod 40 acts on a three-armed lever 11, 12, 13 mounted loosely on the same shaft 10 as a two-armed lever 21, 22. In the position shown the rod 40 is raised and the arm 12 acts on arm 16 of a three-armed lever 16, 17, 20 and tensions a spring 18. The arm 13 acts on arm 21 against the action of a spring 25 and moves 21 to the position shown in which it is locked by a spring-controlled catch 23. When rod 40 is lowered the spring 18 rocks the lever 16, in a clockwise direction under the control of clockwork 14 until, after a predetermined interval, the contact 35 on lever arm 20 closes the buzzer contacts 36. The arm 20 is connected by a slotted link 38 to catch 23, so that finally this catch is released and spring 25 rocks the lever 22 so as to rock a switch lever 27 which closes the switch 7, Fig. 1, to operate the brake valve and open the main motor circuit.