GB956682A - Improvements in or relating to circuit breakers - Google Patents

Abstract

956,682. Automatic circuit-breakers; tumbler switches. AIRPAX ELECTRONICS Inc. March 27, 1961 [June 22, 1960], No. 11074/61. Heading H2B. In an automatic circuit-breaker having cooperating contacts on first and second pivoted levers the first lever is by an electromagnetically releasable latch and the second lever is resilient and rotatable by a manually operated toggle mechanism which is adapted to flex the second lever in the contact closed position. As shown, both contact levers 28, 24 are pivoted at 23 to the frame 2 and carry respective contacts 29, 27. The levers are biased apart by a spring 23<SP>1</SP> on the pivot 23 and the clockwise movement of the lever 28 is normally limited by its engagement with a latch 22. The resilient lever 24 is pivotally connected at 25 to a toggle link 26 having its other end pivoted at 33 on the end of a handle 6 which has a fixed pivot 7. A compression spring 38 between a block 34 on the pivot-pin 33 and a pivoted block 35 biases the toggle links to the Fig. 1 position. When the handle 6 is moved to the Fig. 2 position the contact 27 engages the contact 29 before the toggle pivot 33 crosses the centre line between pivots 25, 7. During the final over-centre movement the lever 24 is stressed and when the movement is complete the biasing force of the lever 24 on the pivot 25 of the toggle 26, 6 is sufficient to hold the toggle over-centre against the component of the force of the spring 38 normal to the axis 25, 7. On overload the series electromagnet 11, 13 attracts a balanced pivotal armature 16 which during its movement engages a co-pivotal member 21 having an extension forming the latch 22 which releases the lever 28. The lever 28 moves clockwise reducing the stress on the lever 24 so as to allow the spring 38 to move the toggle 26, 6 over-centre and restore the switch to the Fig. 2 position. A pin 31 on the link 26 engages the end 30 of the lever 28 to reset the latch 22 and lever 28. The metal casing 45 is sealed to the switch mounting plate 1 and to terminal bushings 10 and a rubber diaphragm 8 completes the sealed enclosure.