A molded case circuit breaker comprising a contact arm movable between circuit closed and open positions, a collapsible mechanism including a releasable member having one end normally engaged with a latch member of an automatic trip unit, a pair of toggle links provided between the movable contact arm and the releasable member, and a tension spring stretched between a manually operable handle and a toggle knee of the toggle links, the other end of the releasable member having a wedge member swingably mounted thereto. When an automatic trip occurs, the wedge member slidably enters between one of the toggle links and a stationary pin secured to the molded case to prevent the contact arm from rebounding toward its circuit closed position.
A circuit interrupter comprises a toggle link having an upper toggle link and a lower toggle link pivotally connected by a knee pin to each other, a movable contact arm having a movable contact element secured thereon and connected to the lower toggle link of the toggle link, and a toggle link stopper capable of contacting the upper toggle link for preventing the bouncing back of the movable contact arm during tripping of the movable contact arm. The toggle link stopper is provided with a first stop surface which is brought into engagement with the upper toggle link when the movable contact arm is being tripped open and a second stop surface which is brought into engagement with the upper toggle link at a position closer to the knee pin than to the first stop surface when the movable contact arm is bouncing back. Thus, the toggle link is engaged by two stop surfaces at two stages, enabling the preventing of the bouncing of the movable contact arm.
An electric circuit breaker includes thermal magnetic trip means for causing circuit interruption upon the occurrence of overload and minor short-circuit conditions, and also provides current limiting action under major short-circuit conditions by providing two pairs of engageable contacts, wherein one contact of each pair is movable to a circuit interrupting position by the circuit breaker operating mechanism and the other contact of each pair is magnetically attracted to a circuit interrupting position in response to short-circuit currents exceeding a predetermined magnitude.
A single pole molded case circuit breaker having a spring powered trip free contact operating mechanism including an extendable toggle connected at one end to a releasable cradle and connected at the other end to a movable contact, a latch for holding the cradle in reset position, and an automatic trip means for operating the latch to release the cradle upon the occurrence of predetermined overload conditions, is provided with anti-rebound means which prevents the movable contact from moving toward closed circuit position except under the influence of the operating mechanism. The anti-rebound means includes engaging formations of the cradle and toggle which cooperate to block the toggle from being extended unless the cradle is in its reset position. As the cradle moves to trip position it engages the toggle to kick the contact arm toward open position.
A circuit breaker includes main circuit contact shoes disposed in a circuit breaker case and urged by a contact spring, a contact opening and closing mechanism located above the contact shoes and including an opening and closing lever, a toggle link, an opening and closing handle and a latch, and an overcurrent tripping device located above the contact shoes. The toggle link includes a first link extending between the opening and closing lever and a toggle shaft located above, and a second link extending between the toggle shaft and the latch to overlap the first link in the V-form, and an opening and closing spring extends between the toggle shaft and a tip of a handle lever coupled to the opening and closing handle to extend downward. As a result, a space occupied by the contact opening and closing mechanism section in the height direction can be reduced to make the circuit breaker more compact.
A circuit breaker apparatus characterized by a molded case containing a circuit breaker structure for opening and closing a circuit which structure comprises a releasable lever operable between latched and unlatched positions corresponding to open and closed circuit conditions, latch means including a latch lever for the releasable lever, interconnected toggle connected to the latch lever and that are biased to the unlatched position of the lever, and a movable trip bar responsive to predetermined overcurrents and having a projection contacting the toggle links for holding the links in the unbiased position.
