Abstract: A molded case circuit breaker includes a generally "Z" shaped intermediate latch structure which has upper and lower substantially planar sections that are each bent at an angle with respect to a center pivot section. The upper portion of the intermediate latch includes one or two latch surfaces. One of these latch surfaces engages the cradle of the operating mechanism of the circuit breaker, to latch the operating mechanism when the circuit breaker is closed. The other latch surface engages a trip bar or an intermediate latch bar, which is rotated by the trip unit when an overcurrent condition occurs. The lower portion of the intermediate latch structure also includes a latch surface which may engage a trip bar. This latch surface is sloped such that when the latch surface of the trip bar is moved along this sloped latch surface, the trip bar rotates.

Abstract: A thermal and magnetic trip unit for a multi-pole circuit breaker includes a thermal structure having a bimetallic element and one or more heater elements. Each of the heater elements and a portion of the bimetallic element is generally "U" shaped defining a conductive path which extends from one leg of the U to the other leg. The heater elements and bimetallic element may be configured in parallel to reduce the level of current flowing through the bimetallic element and thus increase the current level at which the bimetallic element will trip the breaker. Alternatively, the heater elements may be configured in series with the bimetallic element, by inserting electrical insulators between the bimetallic element and each of the heater elements and connecting the various "U" shaped elements using a connecting bus which connects the second leg of one element to the first leg of the next element.

Abstract: A cable interlock system for preventing at least two circuit breakers from being closed at the same time, comprising a first circuit breaker having a first operating handle, wherein the first operating handle is adapted to close or open the first circuit breaker, a second circuit breaker having a second operating handle, wherein the second operating handle is adapted to close or open the second circuit breaker, a first mounting bracket that is attached or secured to or otherwise associated with the first circuit breaker, a first lever arm movably attached or secured to or otherwise associated with the first mounting bracket, a second mounting bracket that is attached or secured to or otherwise associated with the second circuit breaker, a second lever arm movably attached or secured to or otherwise associated with the second mounting bracket, a cable assembly having one end adapted to be connected to the first lever arm of the first mounting bracket and having another end adapted to be connected to the second

Abstract: A circuit breaker including a sliding connection between a trip unit and associated contact arm is disclosed herein. The sliding connection facilitates assembly of the circuit breaker and also permits a reduction of size for a circuit breaker of a given rating. An embodiment of the sliding connection includes a blade and jaw assembly connected between the trip unit and contact arm. Another embodiment of the sliding connection includes a blade or jaw assembly slidably connected directly to the contact arm.

Abstract: A circuit breaker including a sliding connection between a trip unit and associated contact arm is disclosed herein. The sliding connection facilitates assembly of the circuit breaker and also permits a reduction of size for a circuit breaker of a given rating. An embodiment of the sliding connection includes a blade and jaw assembly connected between the trip unit and contact arm. Another embodiment of the sliding connection includes a blade or jaw assembly slidably connected directly to the contact arm.

Abstract: A current limiting circuit breaker including novel clutch arrangements between the contact arms of the circuit breaker and the crossbar. The clutch arrangements include cam surfaces formed on the crossbar from plastic and a cam follower attached to each contact arm. A cam surface is located on each side of each contact arm and each surface may be formed integrally with an insulating barrier. To reduce wear on the cam surfaces, each cam follower includes a roller which contacts the respective cam surface. The cam surfaces are configured to permit the contact arms to blow open under unacceptable fault conditions even though the crossbar remains stationary.

Abstract: An improved circuit breaker with moving line and load contacts is disclosed herein. The circuit breaker includes an enclosure for the operational components thereof including a line contact arm and associated contact for each phase of the circuit breaker, and an operating mechanism supported within the enclosure to move the contact arm(s) between open and closed positions. The circuit breaker also includes a terminal for each phase pivotally supported within the enclosure, and a load contact arm and associated contact for each phase pivotally connected to the terminal. The contact arms are supported so the contacts are engaged when the line contact arms are in the closed positions. The pivoted load terminal(s) allow the use of multiple connector types with the terminal(s), and the pivoting connection between the load contact arm and associated terminal facilitates a reduction in circuit breaker size for a given rating.

Abstract: A current limiting circuit breaker including a novel spring arrangement between the contact arms of the circuit breaker and the crossbar. The spring arrangement includes a single spring which holds the cam follower attached to each associated contact arm in contact with cam surfaces of the crossbar. The longitudinal axis of the spring is located within a plane passing through the longitudinal axis of the contact arm, wherein the plane is also perpendicular to the rotational axis of the contact arm. The cam surfaces and spring are configured to permit the contact arm to blow open under unacceptable fault conditions even though the crossbar remains stationary.

Abstract: A multi-phase circuit breaker including novel crossbar for opening and closing the circuit breaker contact arms. The crossbar is a one-piece plastic component molded to include an operating arm, insulating barriers for separating the contact arms of each phase, and the cam surfaces which interact with the cam followers of the contact arms. The operating arm is linked to the operating mechanism of the circuit breaker so that operation of the mechanism will pivot the crossbar which pivots the contact arms between their open and closed positions.

Abstract: A remote tripping mechanism for use with a spring loaded safety switch. In a preferred embodiment, the mechanism is made up of two cams with a compression type trip spring anchored between them. The two cams are held in the "normal position" (the spring compressed) by a latch. In this position, the switch operates in the same manner as a conventional safety switch. A trip lever connected to a solenoid is positioned such that it is unobtrusive when the switch is turned ON and OFF. When the switch is in the ON position and power is applied to the solenoid, the trip lever unlatches the latch and the two cams separate. The first cam engages and lifts the bail, turning the switch OFF. The cams are reset by turning the handle to the OFF position. This compresses the trip spring and resets the latch.

Abstract: Assemblies for providing the contacts of a circuit breaker with a pivoting motion. Each assembly is adapted to electrically couple the contact to the base of the assembly which is connectable to a terminal of the circuit breaker. Each assembly includes an arm for supporting an electrical contact, a pivot pin for pivotally mounting the arm, a base for supporting the pivot pin, and means for urging the pivot pin into contact with contact surfaces of the base. The arm is pivotable about the longitudinal axis of the pivot pin, and the arm and pivot pin are arranged such that at least two contact locations occur between the arm and the pivot pin.

Abstract: A pivoting lower contact arm arrangement and a circuit breaker including the arrangement. The pivoting lower contact arm arrangement includes a pivoting lower contact arm and a biasing arrangement. The biasing arrangement maintains the contact arm in an operating position with a first force, and biases the arm from a blown-open position toward the operating position with a second force. The first force is greater than the second force to provide increased separating speed when the pivoting lower contact arm blows apart from a pivoting upper contact arm of the circuit breaker and moves from its operating position. The biasing arrangement also variously provides magnetic shielding and coupling between the pivoting lower contact arm and other current carrying components of the circuit breaker. The magnetic shielding enhances the blow-apart forces between the pivoting upper contact arm and the pivoting lower contact arm.

Abstract: A pivoting lower contact arm arrangement and a circuit breaker including the arrangement. The pivoting lower contact arm arrangement includes a pivoting lower contact arm and a biasing arrangement. The biasing arrangement maintains the contact arm in an operating position with a first force and biases the arm from a blown-open position toward the operating position with a second force. The first force is greater than the second force to provide increased separating speed when the pivoting lower contact arm blows apart from a pivoting upper contact arm of the circuit breaker and moves from its operating position. The biasing arrangement also variously provides magnetic shielding and coupling between the pivoting lower contact arm and other current carrying components of the circuit breaker. The magnetic shielding enhances the blow-apart forces between the pivoting upper contact arm and the pivoting lower contact arm.

Abstract: A circuit breaker including a contact operating mechanism configured to prevent the switch handle of the circuit breaker from being placed in an OFF position when the contacts are not separable. In addition to the switch handle, the mechanism is operable with a tripping circuit which actuates the mechanism to urge the contacts apart when the current flowing through the circuit breaker exceeds the preset limits of the circuit breaker. When the contacts are not separable and the tripping circuit actuates the mechanism, the operating handle is restricted from being placed in the OFF position, thereby avoiding the possibility of indicating an incorrect position of the contacts.

Abstract: An improved connection assembly which saves space and eliminates the need for many conventional fastener means such as nuts and flanges. The assembly includes a receptacle for accepting and engagement member, wherein a small amount of clearance is present between the receptacle and the engagement member. The engagement member includes a slot having two substantially parallel surfaces. A threaded fastener is used to fix the engagement member within the receptacle by passing the fastener through an opening in the bottom of the receptacle and causing the threads of the fastener to cut into and engage the surfaces of the slot.

Abstract: A multipole molded case circuit breaker has a single handle assembly contained in a first pole along with a movable contact arm assembly. A second pole has a movable contact arm assembly connected to the first contact arm assembly by a crossbar member so that the arms move in unison during normal operation. Each pole contains a tripping mechanism for tripping the breaker pole. The breaker mechanisms are connected for uniform tripping of all poles.

Abstract: A line terminal assembly is provided for a circuit breaker. The line terminal assembly includes a line terminal which has an interior arm and first and second exterior arms with a bimetallic element connected to the interior arm. A screw passes through a bracket and threadably engages the interior arm. Torquing the screw causes the interior arm and bimetallic element to move relative to the exterior arms thereby varying the tripping current of the breaker.

Abstract: A circuit breaker has a bimetallic element and an electromagnetic element. The bimetallic element has one end connected to the line terminal and the other end connected to the pigtail connector. A shunt is connected at one end to the pigtail connector and has a contact on the other end matable with the line terminal contact. The shunt is connected at one end to the pigtail connector immobilizing the pigtail so that it does not interfere with the operation of the bimetallic element. The electromagnet is positioned about the bimetallic element and has an armature which is movable to trip the circuit breaker. The shunt element has a spring connected which biases the armature away from the electromagnet.

Abstract: A circuit breaker with blow open contacts is provided with a housing. Each pole of the circuit breaker has a reinforced molded housing. The walls of the housing are provided with reinforcing ribs to withstand the high pressures caused by gases generated by the arc during interruption of high short circuit currents.

Abstract: A blow open contact arm assembly is provided for a molded case circuit breaker. A ferromagnetic carrier is attached to the movable contact arm and is positioned thereabout for creating a magnetic field about the movable contact arm which attracts the contact arm to the open position during severe fault conditions. The molded case housing has reinforced walls to withstand the pressures exerted on the walls of the houses during a blow open operation of the contacts.