Abstract: A circuit breaker includes terminals with screws on a power supply side and a load side disposed at a front end section and a rear end section of a main body case containing a current interrupting unit and a switching mechanism. A terminal cover is detachably attached onto the main body case at a position corresponding to the terminals on at least one of the power supply side and the load side. A terminal cover attaching surface is formed on an upper surface on the power supply side and/or the load side of the main body case. The terminal cover is inserted while sliding on the attaching surface from a front end, so that the terminal cover is attached to the main body case with a snap-fit coupling unit at an assembling position.

Abstract: A circuit breaker includes terminals with screws on a power supply side and a load side disposed at a front end section and a rear end section of a main body case containing a current interrupting unit and a switching mechanism. A terminal cover is detachably attached onto the main body case at a position corresponding to the terminals on at least one of the power supply side and the load side. A terminal cover attaching surface is formed on an upper surface on the power supply side and/or the load side of the main body case. The terminal cover is inserted while sliding on the attaching surface from a front end, so that the terminal cover is attached to the main body case with a snap-fit coupling unit at an assembling position.

Abstract: An overload/open-phase tripping device for a circuit breaker includes a plurality of bimetallic elements arranged in a row; a differential shifter mechanism; and a tripping lever for transmitting a force applied by the differential shifter mechanism to a switching mechanism. The differential shifter mechanism includes a push shifter having a plurality of operation ends; a pull shifter having a plurality of operation ends; and a differential lever disposed between the push shifter and the pull shifter. The differential lever is provided with an action end for applying the force to the tripping lever upon an overload, and an action end for applying the force to the tripping lever upon an open-phase. The two action ends face the tripping lever, and the action end for the open-phase is located at a position farther from the tripping lever than the action end for the overload.

Abstract: An overload/open-phase tripping device for a circuit breaker includes a plurality of bimetallic elements arranged in a row; a differential shifter mechanism; and a tripping lever for transmitting a force applied by the differential shifter mechanism to a switching mechanism. The differential shifter mechanism includes a push shifter having a plurality of operation ends; a pull shifter having a plurality of operation ends; and a differential lever disposed between the push shifter and the pull shifter. The differential lever is provided with an action end for applying the force to the tripping lever upon an overload, and an action end for applying the force to the tripping lever upon an open-phase. The two action ends face the tripping lever, and the action end for the open-phase is located at a position farther from the tripping lever than the action end for the overload.

Abstract: In a terminal device of a switching device, a terminal screw with a washer is screwed in a terminal strip having a screw hole therein for connecting an external wire. The terminal strips are placed on terminal boards of power supply side and load side formed at both ends of a switching device case. A case cover covers the terminal screw, and a screwdriver is inserted through an insertion hole formed in an upper surface of the case cover to tighten the terminal screw. The terminal device includes a terminal lifter connected to the terminal screw for manually lifting the terminal screw upwardly from the upper surface of the case cover, so that the terminal screw is temporally attached to the case cover at a lifted position after the terminal screw is loosened and detached from the terminal strip with the screwdriver.

Abstract: A circuit breaker has a main housing, and a pocket-shaped auxiliary equipment storage section is formed in the housing. A cassette type auxiliary switch is inserted into and attached to the auxiliary equipment storage section. The auxiliary switch is connected to a switching mechanism in the main housing of the circuit breaker so that the circuit breaker performs switching operations. The circuit breaker includes a locking device for positioning the auxiliary switch inserted into the auxiliary equipment storage section at a predetermined position. Further, an engagement-type stopper is provided for fixing the auxiliary switch at the position where the auxiliary switch is inserted into the auxiliary device storage section.

Abstract: A circuit breaker includes a rectangular box-shaped intermediate housing and lower housing; a power supply side fixed contact and a load side fixed contact disposed in the intermediate housing and facing each other; and a movable contact housed in the lower housing for bridging the power supply side fixed contact and the load side fixed contact. The lower housing has arc gas emission holes formed in front and rear walls thereof, and is connected to a lower part of the intermediate housing via an engagement part such that the lower housing covers the lower part of the intermediate housing. A thin wall portion is formed in each of the front and rear walls to eject arc gas by bending.

Abstract: An alarm output device is capable of outputting a mechanical alarm signal to attached alarm switches in linkage with a tripping operation of a circuit breaker. The alarm output device includes an alarm output plate provided on an outer lateral surface of a frame of an opening/closing mechanical unit and is operable in linkage with a latch of the opening/closing mechanical unit, so that a movement of the alarm output plate is transmitted to the attached alarm switches to perform a switching operation. The alarm output plate is provided with a pair of operation terminal members corresponding to an internal alarm switch and an external alarm switch of the circuit breaker.

Abstract: An external auxiliary switching unit includes a unit case, an auxiliary contact mechanism having contacts to be opened and closed in response to on/off operations of a circuit breaker, and an alarm contact mechanism operating in response to a tripping operation of the circuit breaker. An operating arm extends from a contact holder of the alarm contact mechanism and protrudes sideward from the unit case. The operating arm is inserted into a breaker housing when the auxiliary switching unit is mounted onto the circuit breaker. When the alarm output plate rotates upon tripping of the circuit breaker, the alarm output plate is released from the operating arm to detect the tripping and output an alarm signal. After the tripping, the circuit breaker is reset to cause the alarm contact mechanism to return to the non-detecting position via the alarm output plate, thereby stopping the alarm signal.

Abstract: A circuit breaker includes a switching mechanism, a manual operating handle connected to the switching mechanism, and an instantaneous tripping device for detecting a short circuit current and opening contacts of a main circuit. The instantaneous tripping device and a latch receiver of the switching mechanism are connected with each other via a trip member capable of sliding up and down. Further, the circuit breaker includes a trip indicating member moving along with the trip member, and a trip indicating window formed in a breaker housing and facing the trip indicating member. The trip indicating member moves to an indicating position to visually indicate a tripping state of the circuit breaker through the trip indicating window when the circuit breaker member instantaneously trips.

Abstract: A circuit breaker for opening and closing a main-circuit includes main-circuit contacts; an opening-and-closing mechanism having a switching lever for opening and closing the main-circuit contacts, a main spring for urging the switching lever, and a toggle-link mechanism attached to the switching lever; and an operational handle. The operational handle includes a locker handle rotatably supported on a handle pin and connected to the toggle link of the switching mechanism, and a pushbutton linked to the handle. When the pushbutton is pushed, the handle portion rotates to allow the switching lever to close the main-circuit contacts.

Abstract: A circuit breaker includes a rectangular box-shaped intermediate housing and lower housing; a power supply side fixed contact and a load side fixed contact disposed in the intermediate housing and facing each other; and a movable contact housed in the lower housing for bridging the power supply side fixed contact and the load side fixed contact. The lower housing has arc gas emission holes formed in front and rear walls thereof, and is connected to a lower part of the intermediate housing via an engagement part such that the lower housing covers the lower part of the intermediate housing. A thin wall portion is formed in each of the front and rear walls to eject arc gas by bending.

Abstract: A circuit breaker includes a switching mechanism, a manual operating handle connected to the switching mechanism, and an instantaneous tripping device for detecting a short circuit current and opening contacts of a main circuit. The instantaneous tripping device and a latch receiver of the switching mechanism are connected with each other via a trip member capable of sliding up and down. Further, the circuit breaker includes a trip indicating member moving along with the trip member, and a trip indicating window formed in a breaker housing and facing the trip indicating member. The trip indicating member moves to an indicating position to visually indicate a tripping state of the circuit breaker through the trip indicating window when the circuit breaker member instantaneously trips.

Abstract: A circuit breaker has a main housing, and a pocket-shaped auxiliary equipment storage section is formed in the housing. A cassette type auxiliary switch is inserted into and attached to the auxiliary equipment storage section. The auxiliary switch is connected to a switching mechanism in the main housing of the circuit breaker so that the circuit breaker performs switching operations. The circuit breaker includes a locking device for positioning the auxiliary switch inserted into the auxiliary equipment storage section at a predetermined position. Further, an engagement-type stopper is provided for fixing the auxiliary switch at the position where the auxiliary switch is inserted into the auxiliary device storage section.

Abstract: A circuit breaker for opening and closing a main-circuit includes main-circuit contacts; an opening-and-closing mechanism having a switching lever for opening and closing the main-circuit contacts, a main spring for urging the switching lever, and a toggle-link mechanism attached to the switching lever; and an operational handle. The operational handle includes a locker handle rotatably supported on a handle pin and connected to the toggle link of the switching mechanism, and a pushbutton linked to the handle. When the pushbutton is pushed, the handle portion rotates to allow the switching lever to close the main-circuit contacts.

Abstract: A protective switch includes a switch housing, a switching mechanism for closing and opening a movable contact, a tripping mechanism instantaneously pulling a plunger upon detection of an instant current, a tripping control device, an alarm switch, and a trip member. The trip member is divided into an upper trip member away from a bottom of the housing, and a lower trip member close to the bottom of the housing urged by a back spring. The upper trip member includes a plunger operating section opposed to an operating member of the plunger and a switch operating section opposed to an actuator of the alarm switch. The lower trip member includes a locking member operating section opposed to a locking member of a switching mechanism and a tripping section opposed to an operating member of a tripping control device.

Abstract: An overload tripping device includes a temperature-compensating bimetal operating as a tripping lever and interposed between an output lever of a differential shifter mechanism linked with a main bimetal and a latch receiver of an opening-and-closing mechanism section of a circuit breaker. The temperature-compensating bimetal has an intermediate portion journaled on a bimetal holder. An operating arm made of a light molding material is attached to a tip of the temperature-compensating bimetal so as to push the latch receiver. Additionally, a balance weight may be installed on the temperature-compensating bimetal to balance inertial moments on the opposite sides of the bimetal. Thus, the circuit breaker is prevented from being inadvertently tripped due to external stimulus.

Abstract: A circuit breaker is formed of a main body case made of resin and divided into a lower case, an upper cover, and an intermediate case, into which parts of the circuit breaker are integrated. The intermediate case has pocket shaped sockets formed on a top surface side thereof, into which the tips of the interphase partition walls provided in the upper cover are fitted. Also, the intermediate case has recessed grooves formed on a bottom surface side thereof to fit over upper edges of the interphase partition walls provided in the lower case. Thus, the circuit breaker can be assembled easily and becomes more rigid.

Abstract: A mounting structure for mounting a switch device includes a main body case for the switch device having slots formed in lower portions of the front and rear surfaces, and mounting plates to be inserted into the slots. Each mounting plate has a screw hole at one end and an insertion portion at the other end The insertion portions are inserted into the slots to allow the main body case to be fixed by the mounting plates. The switch can be mounted using screws inserted into the screw holes in the mounting plates.

Abstract: In an instantaneous-tripping circuit breaker, a heater-mounted main bimetal, a shifter of a differential shifter mechanism, and an adjustment dial of a thermal overload/open-phase tripping device are removed from a standard circuit breaker equipped with a breaking section, an opening and closing mechanism section, a thermal overload/open-phase tripping device, and an electromagnetic instantaneous tripping device in a case. Instead, a trip coil of the instantaneous tripping device is connected to a main circuit via a connection conductor of a low resistance, a test-tripping part is mounted in place of the shifter of the differential shifter mechanism, and the adjustment dial is replaced with a dummy dial. Accordingly, the standard circuit breaker is changed to an instantaneous-breaking circuit breaker.