GB742541A - Improvements in and relating to indicators for quick-action electric switches - Google Patents

Abstract

742,541. Snap-action switches. ENGLISH ELECTRIC CO., Ltd. Feb. 5, 1954 [Feb,. 6, 1953] No. 3408153. Class 38(5) A switch having an "on" "off" indicator 31 operated directly by the moving contact assembly comprises a pair of spaced slotted bars 2 (only one shown) each receiving a pair of pins 6, 7 on spaced yoke members 5 connected by insulating bars 4 carrying pairs of movable contacts 8, the pins 6, 7 being slidable in the slots so that the contacts 8 may co-operate with respective pairs of fixed contacts 3, the contacts 8 being bridged by fuses 9. An operating lever 10 pivoted at 11 is connected at 14 to a spring- loaded toggle lever 12 pivoted at 13 and to a slotted link 15 having a lost-motion connection with a pin 7. A spring 16 acting tween the pin 7 and a bracket 15b on the link 15 holds the moving contacts stationary until the lost-motion is taken up. The lever 10 is duplicated at the other end of the shaft 11 and connected through a further link 15 to the pin 7 of the other yoke member 5. The lever 12 may also be duplicated. The lever 10 is connected through a link 17 to a member 18 pivoted at 19, a boss 21 of the member 18 slidably receiving an operating handle 22 having a finger-grip portion 23 and a stop pin 24. The switch is operated by opening a, flap in the cover 26, pulling out the handle 22 to the limit determined by the stop 24, and rocking the handle to. move the levers 10, 12 overcentre, the lost-motion link 15 ensuring snap-action of the contacts. The indicator 31, visible through a window 32 of the cover 26, is carried by a lever 30 pivotally mounted on a fixture 20, the lever having a slot 29 receiving a pin 23 carried by a, bracket 27 riveted to a yoke member 5. The slot 29 is so shaped and positioned that the lever 30 is moved only when the toggle 10, 12 has reached the dead-centre position; also, when the contacts are being closed the indicator registers "on," Fig. 4, before the contacts engage, the pin 28 being at the left-hand end of the slot 29 in the closed condition of the contacts. On opening the contacts the dead-centre is passed at the position of the pin 28 shown in Fig. 4 whereby the indicator cannot register "off" until the contacts have separated, Fig. 1. Specifications 742,880 and 742,881 are referred to.