Multi-pole circuit breaker with an interchangeable thermal-magnetic trip unit

Claim 1

Low voltage multipole electric circuit breaker formed by the modular assembly of a interrupting unit (10) having a molded insulating casing (12) subdivided into several poles placed side by side, and of a magnetothermal release unit (44) interchangeable in terms of the chosen rating, each pole of the interrupting unit (10) comprising a pair of separable contacts (32, 34), the fixed contact (34) of which is connected to a connection supply-side terminal (38) of the circuit breaker, and the moving contact (32) of which is electrically connected to a binding lug (52R, 52S, 52T, 52N) likely to be brought into contact by superimposition with a connection lug (50R, 50S, 50T, 50N) of the release unit (44), the casing (46) of which takes support in fastened position on the casing (12) of the interrupting unit (10), said release unit (44) comprising a thermal release and an electromagnetic release driven by the current flowing in the conductor (84) aligned with the pair of contacts in the longitudinal direction of the pole, said connection lug (50R, 50S, 50T, 50N) being disposed at one of the conductor (84) ends, the opposite end of which is linked together onto the connection load-side terminal (80) of the circuit breaker, the electric continuity by pole between the conductor (84) of the release unit (44), and the pair of contacts (32, 34) of the interrupting unit (10) being ensured by a connection screw (54) assuring the tightening of the pair of the intermediate binding and connection lugs (52R, 50R; 52S, 50S; 52T, 50T; 52N, 50N) in superimposed position, characterized in that a flexible shunt (64, 66) of the moving contact arm (30) is directly secured to the binding lug (52R, 52S, 52T, 52N) of each pole, comprising a contact face (62) cooperating with the associated connection lug (50R, 50S, 50T, 50N), and an opposite face (60) equipped with a nut (58), and that each binding lug (52R, 52S, 52T, 52N) is positioned in vertical play in a cross-groove (68) of the casing (12) of the interrupting unit (10), the tightening of the connection screw (54) introduced in the nut (58) in fastened position of the release unit (44) on the casing (12) biasing said floating binding lug (52R, 52S, 52T, 52N) in the direction of said play to ensure a good electric contact with the corresponding connection lug (50R, 50S, 50T, 50N) of the release unit (44), independently of the positioning faults of both casings (12, 46).