Patent GB-179882-A (GB)
Title: Improvements in and relating to electric switches
IPC: H01H1/50
Filed: 1921-02-02
Abstract: 179,882. British Thomson - Houston Co., Ltd., (General Electric Co.). Feb. 2, 1921. Automatic circuit-breakers; oil switches. - Relates to actuating-mechanism for oil switches of the type shown in Fig. 1 in which a common actuating - mechanism 7 is coupled to the operating- mechanism of three switch units 1, 2, 3, each unit having relatively movable cooperating contacts 4, 5. The actuating-mechanism, Fig. 2, is mounted on an insulating- base 14 in a casing 8 secured to channel-iron supports 9 over the oil tank and comprises an operating-shaft 28 to which are secured operating-levers 29, 30, the shaft 28 also carrying one arm of an operating-toggle 26, 27, the arm 26 having an adjustable stop 31 co-operating with a fixed abutment 32 to hold the toggle in its nearest underset position. The link 27 is pivotally secured to an intermediate or actuator member 35 movable about a fixed pivot 23. Between the actuator member 35 and the operating-link 21 of a parallel-motion mechanism 19, 20, 21, pivoted at 23, one side of which is formed by an extension 16 of the operating-rod 15, there is placed a collapsable toggle 36, 37 provided with latching mechanism carried by the member 35. The operating rod 15 is attached to a reciprocating switch rod 17 bearing the movable contact bar 5, the sleeve 17 being guided in an insulating sleeve 18. The latching-mechanism for the toggle 36, 37 comprises members 38, 39 secured between the link 37 and a lateral projection of the member 35, the nose 40 of the member 38 co-operating with a hooked latching-member 41 pivotally secured to the member 35. Fig. 2 indicates the position of the mechanism when the switch is closed. To open the switch the tail of lever 42 is engaged either through a rod 43 by the armature 42 of a tripping electromagnet, or by a backward movement of the operating-levers 29, 30 during which a link 46 moves a pivoted member 45 which in turn strikes the lever 41. When the tail of the lever 41 is thus raised its hooked projection is thereby disengaged from the nose 40 of the latching-mechanism 38, 39 allowing the connection 36, 37 to collapse, the weight of the switch parts causing a quick opening of the switch contacts, Fig. 3. To re-close the switch, the actuating-levers 29, 30 are moved counter-clockwise, carrying the member 35 into a position in which the nose 40 of the latching-mechanism is again engaged by the hooked lever 41, reversal of the closing movement after this occurs effecting the switch closure, during which the toggle 36, 37 is held rigidly in its thrust-transmitting position by means of its latching-mechanism. Guiding-means for the parallel-motion mechanism consist of the usual guide link 22 pivotally secured to the link 19. The means for controlling three switch units by one actuating-mechanism consists of links 24 pivoted at 23 and secured to or made integral with the links 20, the three links 24 being interconnected by rods 25. To act as a buffing-means, an oil dash-pot 47, secured to the base 14, co-operates with a member 48 carried by the arm 15. The length of stroke of the switch rods 17 may be varied by alteration of the height of the dash-pot 47 or of the length of the link 36.