Abstract: A flat plastic retainer having a loop at one end rotatably receiving a threaded fastener and a tongue and outboard fingers unidirectionally extending from the loop to engage an essentially upright leg of a terminal of a circuit breaker, has lateral projections on the tongue which are compressed when the tongue is inserted through an opening in the leg of the terminal and expand when the projections pass beyond the opposite side of the terminal to resist pull-out of the retainer from the terminal. The outboard fingers are deflected along the terminal to bias the fastener into engagement with an associated leg of the terminal having an opening through which one portion of a threaded fastener pair projects to engage the other portion.

Abstract: A contact structure (40, 44; 62, 63) is arranged to provide oppositely directed parallel current paths within a closed loop magnetic flux amplifier (46) to be directly separable under high overload current conditions, the flux amplifier (46) functioning to arrest the movable contact (62, 63) momentum. Manufacturing economies are realized by subassembling the stationary contact structure (40, 42, 44) and flux amplifier (46) and subsequently trapping one end (42a) of that assembly within the base (4a) and securing the other end with a single screw (68). The movable contact arm (62) comprises a plurality of blanked laminations assembled to provide improved contact (63) mounting and bearing (62d) surfaces. The molded case sidewalls are strengthened in the contact separation area by offsetting the parting line (PL) between cover (6) and base (4) closer to the bottom of base (4) and overlapping the thinner base sidewalls with thicker cover sidewalls at the offset (4e, 6e).

Abstract: An arc extinguishing structure for a circuit breaker (2) wherein an arc chute is provided with a pair of transverse barrier plates (38) spaced apart to provide a centrally located opening (40) and spaced away from an upstanding wall (4a) of the breaker housing (4) so as to direct ionized gases associated with an electric arc drawn between separating contacts (8,20) through the arc plates (36) and central opening (40) against the upstanding wall (4a) thereby to be redirected along the wall (4a) and exhausted to the atmosphere through unrestricted openings (6a,4b) provided at opposite upper and lower ends of the wall. The barriers (38) project into the areas of the passageways (6a,4b) to prevent direct access to the switch contacts (8,20) through the passageways and to increase the length of the exhaust path for the arc gases.

Abstract: A contact structure (40, 44; 62, 63) is arranged to provide oppositely directed parallel current paths within a closed loop magnetic flux amplifier (46) to be directly separable under high overload current conditions, the flux amplifier (46) functioning to arrest the movable contact (62, 63) momentum. Manufacturing economies are realized by subassembling the stationary contact structure (40, 42, 44) and flux amplifier (46) and subsequently trapping one end (42a) of that assembly within the base (4a) and securing the other end with a single screw (68). The movable contact arm (62) comprises a plurality of blanked laminations assembled to provide improved contact (63) mounting and bearing (62d) surfaces. The molded case sidewalls are strengthened in the contact separation area by offsetting the parting line (PL) between cover (6) and base (4) closer to the bottom of base (4) and overlapping the thinner base sidewalls with thicker cover sidewalls at the offset (4e, 6e).

Abstract: A Z-shaped bracket (42) is secured to a circuit breaker panel (2) by a fastener (44) to project forwardly along a plug-in main circuit breaker (30) and overlie the forward surface of the main breaker to prevent removal of the main breaker (30) without first removing the bracket (42). The bracket and its function are made plainly evident by placement and indicia.

Abstract: A single-pole circuit breaker or a plural-pole circuit breaker of the type having a common trip bar extending between poles whereby any pole tripping acts therethrough to trip the other pole or poles. The breaker is provided with an improved trip mechanism comprising a subassembly for each pole wherein all of the thermal and magnetic trip elements are mounted on a breaker terminal plate that acts as a base therefor and which is secured to the breaker housing.