GB212011A - Improvements in devices for making and breaking electric circuits - Google Patents

Abstract

212,011. Zweigbergk, T. Dec. 27, 1922. Switches, partly electromagnetic. -A circuitbreaker which may be used in the motor control described in Specification 175,877 [Class 38 (iii), Electric motor control systems &c.] is arranged so that to close the circuit joint mechanical and electromagnetic devices are required, either of which may effect the opening of the circuit. The mechanical device comprises a cam 1 on the motor-driven contactor shaft 41 having a recess 2 co-operating with a roller at the end of a pivoted lever 4. A pair of toggle links 12, 13 extend between the lever 4 and a pivoted lever 16 carrying a contact 17 adapted to co-operate with a fixed contact 18, a spring 19 tending to hold the contacts apart. A link 10 is attached between the common pivot 11 of links 12, 13 and an arm of a bell-crank lever 8, the other arm carrying an armature 7 co-operating with an electro-magnet. 6. When the circuit of the solenoid 6 is closed on moving the master controller from its " off " position the solenoid 6 is energised attracting the armature 7 and bringing the links 12, 13 almost to their dead-centre position. The contact lever 16 is rotated through a small arc, the contact 17 being still some distance from the fixed contact 18 and the spring 19 being only slightly compressed. When the shaft 41 is subsequently rotated the straightened links 12, 13 act as a strut between levers 4 and 16 so that as the roller rides out of the recess 2 the contact 17 is driven home against the fixed contact 18 against the full force of the spring 19. If the master controller is now brought again to the off position the deenergization of the coil 6 and consequent release of the armature 7 allow the links 12, 13 to collapse quickly causing a quick break at contacts 17, 18. A small switch 2 is interlocked with an arm 28 integral with the contact lever 16. The spring-retracted contact lever is pivoted at 23 and operated, when the armature 7 is attracted through a push rod 21. A depending arm 27 of the movable contact member co-operates with a projection 30 on the arm 28 to ensure that this switch is released only after the main circuitbreaker has been opened.