GB134376A - Improvements in Electric Switches or Circuit Interrupters. - Google Patents

Abstract

134,376. Coates, W. A., Dale, W. B., and British Westinghouse Electric & Manufacturing Co. Nov. 19, 1918. Automatic circuit-breakers; electro-magnetic switches.-In automatic circuit-breakers of the loose-handle type in which the operating-handle, or its power-operated equivalent, is connected to the switch-actuating mechanism through a hooked catch which is disconnected (when abnormal conditions arise) by an electro-magnetic tripping device, the catch and tripping device are so arranged that the operative point of connexion of the tripping-means with the catch remains at the same distance from the catch throughout the whole range of movement of the catch during the closing operation of the switch, so that the switch can be tripped equally well at any point in the path of movement of the operating-lever. As shown in Fig. 1, applied to a circuit-breaker electro-magnetically operated by the solenoid plunger 12 through toggle-links 8, 9 and an operating-lever 11 connected between the plunger and the fixed pivot 10 of the toggle, the catch 13 pivoted at the toggle joint is connected by a link 18 to the operative end of the tripping-armature 16 at the point 19 which is co-axial with the fixed pivot of the toggle. Consequently, throughout the closing movement of the switch, the pivot 19 remains unmoved until the tripping-armature is attracted, whereupon the movement of the pivot 19 is transmitted through the link 18 to the catch which releases the toggle linkage, thereby allowing the switch to resume its ' off ' position, under gravity. The operating-lever is raised by the spring 20 to restore the catch into engagement with the pin 15,. if the abnormal conditions have ceased. When the switch has been brought to the closed position by the plunger, it is held there (so that the closing electro-magnet may be de-energized) by a spring detent 21 which may be manually released to trip the switch. The pivoted armature 16 and the link 18 may be replaced by a solenoid core having a flexible connexion passing through an orifice in the fixed pivot of the toggle mechanism and connected with the catch 13. In the construction shown in Fig. 3, the main switch lever 3 is operated by an intermediate lever 29 pivoted at the same point 27 as the operating- lever 26 and connected thereto by a. catch 32. During the closing movement, the cable moves in close proximity to the surface 38, concentric with the pivot 27, of a bar 35 which is connected with the tripping armature 16 so that, when the surface is moved parallel to itself towards the centre by the operation of the armature, the switch is tripped equally at whatever points has been reached in the closing movement.