ES293799A1 - Circuit breaker with releasable cam type mechanism - Google Patents

Abstract

The pivoted contact member 15 of a circuit breaker is manually actuable by a pivoted handle 39 acting through a snap action mechanism consisting of a cam follower roller 26, linked to the handle by an overcentre tension spring 40 and to the contact member by a link 24, and movable between two stable positions on a cam surface 34 of a latched member 30. Upon overload in any phase of the three-phase breaker bimetals 60 bend to tilt a common trip bar 54 through adjusting screw 57 and so to withdraw a first latch 53 permitting a member 50 to pivot about 49 this moves a roller latch 51 permitting a second member 33 to pivot about 45 to release the latched member 30 which pivots anticlockwise allowing the follower 26 to rise and thus all of the moving contacts, which are mounted on a common pivoted bar 21, to open the spring 40 is then in an unstable position and moves the handle 39 until it is arrested in a " tripped " position by a portion 38 of the member 30. The latch mechanism is reset by moving handle 39 to the " off " position. As shown, the " on " position of cam follower 26 is governed by the link 24 engaging a part 15B of the contact arm 15 but in a modification (Fig. 6, not shown) a stop is formed on the latched member 30.