GB812971A - Improvements in or relating to electric circuit breakers - Google Patents

Abstract

812,971. Automatic circuit - breakers; mechanical switches. MECHANICAL PRODUCTS Inc. Feb. 23, 1956 [March 7, 1955], No. 5659/56. Class 38 (5). A circuit-breaker has a rectilinearly-movable actuating member which may be moved to open, close or reset the circuit-breaker and is arranged so that the manual movement of the member to open the contacts 38, 40 is in the reverse direction to the movement of the member when the contacts are tripped open under overload conditions, so that the resultant position of the member indicates the nature of the opening operation. In the arrangement shown, the moving contact assembly is normally latched to a plunger 20 by the engagement of bimetallic members 26 with abutment ledges 28a on the plunger and the contacts 38, 40 are maintained closed by the downward thrust of a spring 64 acting on a flange 20e of the plunger, Fig. 2. To open the contacts manually, the plunger is pulled up so that the flange 20e is moved above angular projections 62 of flexible blades 58 which then retain the plunger in the contact open position. Under overload conditions, the members 26 disengage from the ledges 28a and the moving contact assembly is pulled upwardly by springs 22 into the position shown in Fig. 3, the plunger 20 being pushed down by the spring 64 until the end 44 of the plunger abuts the bottom of the casing 10. Re-setting is effected by pulling up the plunger 20 until the bimetallic members re-engage with the ledges 28a. The plunger is then depressed to reclose the contacts. The plunger may have a black knob 20b and red and white portions 20c, 20d for indicating purposes. Specifications 756,764 and 767,229 are referred to.