JP2003007188A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker enabling easy inspection of its characteristics and easy adjustment of its characteristics. SOLUTION: The circuit breaker has a cover 1b inside which a pair of sub partitioning ribs 72 and 72 facing each other is formed in width direction of the cover 1b. Stoppers 73 and 73 which contact with ends of a handle axis 8 and are caught at them are disposed at positions on facing surfaces of the sub partitioning ribs 72 and 72 respectively, wherein the positions front on a handle inserting hole 29. As a body 1a can pre-fix the cover 1b by catching the stoppers 73 and 73 at the ends of the handle axis 8 and lifting of the cover 1b from the body 1a can be prevented without fixing the cover 1b to the body 1a with screws, inspections of its characteristics can be carried out easily by clearing anxiety about imprudent open main circuit state caused by handle hitting to an inner wall of the handle inserting hole 29 of the cover 1b and the cover 1b can be split away easily from the body 1a by releasing caught state of the stoppers 73 and 73 at the ends of the handle axis 8. Thereby easier characteristics adjusting work than that of a conventional circuit breaker becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker.

[0002]

2. Description of the Related Art Conventionally, there has been provided a circuit breaker which is assembled by assembling parts from a front opening into a box-shaped body having an opening at the front and then attaching a cover to the front side of the body ( See Japanese Patent Application Laid-Open No. 8-264098).

[0003]

In the conventional example described above, the handle protruding from the handle insertion hole formed in the front surface of the cover with the cover attached to the body is operated to the closing position to operate the tripping device for an overcurrent. When performing the characteristic test, if the body and the cover are not fixed, the cover may lift up from the body, and the handle may hit the periphery of the handle insertion hole of the cover and carelessly rotate to open the contacts of the main circuit. there were. For this reason, a characteristic test is performed on the finished product in which the body and cover are fixed with screws, and when adjusting the characteristics of the trip device according to the results of the characteristic test, use a tool to remove the screws and cover the body. Therefore, there is a problem that the characteristic test and the characteristic adjustment work are very troublesome.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a circuit breaker capable of easily performing a characteristic test and a characteristic adjustment work.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 is formed in a box shape having an opening on the front surface, and a main circuit is provided in each of a plurality of internal spaces partitioned by a plurality of partition walls. Body for accommodating each pole, a cover attached to the front side of the body, a handle at least a part of which is exposed through a handle insertion hole provided on the front side of the cover, and a rotation fulcrum of the handle attached to the handle. Handle shaft, a frame attached to the body to support the handle shaft, an opening / closing mechanism that opens and closes the main contact of each pole in accordance with at least the turning operation of the handle, and when an abnormal current flows in the main circuit. And a tripping means for forcibly opening the main circuit by operating the opening / closing mechanism, and a locking portion for locking the end of the handle shaft is provided inside the cover. It can be temporarily fixed to the body and cover by locking the locking portion to the end. For this reason,
Prevents the cover from rising from the body without fixing the cover to the body with screws, and facilitates characteristic testing without the risk of the handle hitting the peripheral edge of the handle insertion hole and opening the main circuit carelessly. become. Further, the body and the cover can be easily separated by releasing the locked state of the end portion of the handle shaft and the locking portion, and the characteristic adjustment work can be performed more easily than in the conventional example.

The invention of claim 2 is characterized in that, in the invention of claim 1, a pair of engaging portions for engaging with both ends of the handle shaft are provided, and the cover is temporarily fixed to the body in a stable state. can do.

The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the cover is formed of a thermoplastic resin, and the cover is easily elastically deformed, and is easily locked to the end of the handle shaft. The part can be locked.

The invention of claim 4 is the invention of claim 1 or 2 or 3.
In the invention of claim 1, a frame is disposed between the partition walls of the body facing each other, and a plurality of auxiliary partition walls are formed inside the cover to abut against each partition wall in the state where the cover is attached to the body, and the end of the handle shaft is The locking part is provided on the auxiliary partition wall facing the section, and the locking part is easily locked to the end of the handle shaft by utilizing the elastic deformation of the auxiliary partition wall provided with the locking part. can do.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

The circuit breaker of this embodiment is an earth leakage breaker with a neutral wire open phase protection used for a main switch of a distribution board for a house, and is a rectangular parallelepiped synthetic resin case. Has 1. The case 1 is composed of a box-shaped body 1a having an open front surface and a cover 1b having a box-shaped opening with a back surface and attached to the front surface of the body 1a. A terminal block 30 is formed on the upper end portion of the body 1a, and three input terminals 3, 3, 3 each including a screwed terminal having a terminal screw 32 are arranged side by side in the left-right direction on the terminal block 30. A single-phase three-wire type neutral wire is connected to the central input terminal 3, and voltage lines are connected to the input terminals 3 and 3 on both sides. An insulating wall 35 is formed on the terminal block 30 to insulate the adjacent input terminals 3 from each other. Further, as shown in FIG. 3, the terminal mounting portion 10 continuously and integrally projects upward from the right end portion of the upper end portion of the body 1a, and the three output terminals 4, 4, 4 project from the right side surface of the terminal mounting portion 10. It is arranged in the form of. Thus, the input terminals 3, 3, 3 and the output terminal 4,
There is a one-to-one correspondence with the input terminals 3 and 4,
Voltage conductors and neutral conductors (not shown) are connected to 3 and 3, respectively, and conductive bars (not shown) to be the busbars are respectively used for the output terminals 4, 4 and 4 by using terminal screws. Connected. Further, inside the terminal mounting portion 10, a storage portion 15 for storing a connecting wire 7 which will be described later is formed.
The terminal block 30 and the terminal block 30 are separated by a partition wall 27.

As shown in FIG. 3, in the body 1a, three main contacts 26, 26, 26 arranged side by side in the width direction of the body 1a (horizontal direction in FIG. 3), an opening / closing mechanism section 5,
A zero-phase current transformer CT that detects a leakage current such as a leakage current or a ground current flowing in an electric path (main circuit) in which the main contacts 26, 26, 26 are inserted, and a main contact 26 when the leakage current flows. , 2
Operation control of the first electromagnetic release device 9A for operating the opening / closing mechanism part 5 to forcibly open the electrodes 6, 26, and the first electromagnetic release device 9A according to the detection output of the zero-phase current transformer CT. And a second electromagnetic release device 9B for operating the opening / closing mechanism section 5 so as to forcibly open the main contacts 26, 26, 26 when a phase loss of the neutral line occurs. ,
An open-phase protection circuit 51 that detects the open phase of the neutral wire and controls the operation of the second electromagnetic release device 9B, and a main contact when an abnormal current such as a short-circuit current or an overload current flows in the circuit. Two
6 and 26, and trip devices 6 and 6 for operating the opening / closing mechanism section 5 to forcibly open the electrodes,
Connect the three-pole main contacts 26, 26, 26 to the case 1 (cover 1
It can be opened and closed by a single handle 2 which is exposed on the front surface of b).

The body 1a is formed with partition walls 28 for partitioning the inner space into each pole, and the cover 1b is also formed with auxiliary partition walls 72 for partitioning the inner space into each pole. When the case 1 is assembled by connecting the 1b, the partition wall 28 of the body 1a and the auxiliary partition wall 72 of the cover 1b are butted against each other to form three spaces for insulating and accommodating the three electric paths including the main contact 26.

The main contact 26 is fixed to the tip of an L-shaped contact holding piece 33, 33, 33 extending from the lower edges of the terminal plates 31, 31, 31 of the input terminals 3, 3, 3. The fixed contacts 21, 21, 21 and the movable contact 22 fixed to one end in the longitudinal direction of the movable contacts 25, 25, 25 formed of a conductive metal in a strip shape and brought into contact with and separated from the fixed contacts 21, 21, 21. , 22, 22. Here, the movable contacts 25, 25 corresponding to the input terminals 3, 3 on both sides connected to the voltage line are respectively connected to the trip devices 6, 6 by the connecting wires 7a, 7a made of a braided wire, and further tripped. Device 6,
Reference numeral 6 is connected to output terminals 4 and 4 corresponding to the input terminals 3 and 3 via connecting wires 7b and 7b made of covered electric wires. The movable contact 25 corresponding to the central input terminal 3 connected to the neutral wire is connected to the output terminal 4 corresponding to the input terminal 3 via the connecting wire 7b. Further, these connecting wires 7b, 7b, 7b are inserted into the through holes of the toroidal core of the zero-phase current transformer CT housed in the lower part of the case 1 and along the lower surface and the right side surface inside the body 1a. It is routed inside an L-shaped storage portion 15 formed inside.

A handle insertion hole 29 opening in a rectangular shape is formed at a central position on the front surface of the cover 1b, that is, at a position facing the central space among the three spaces formed in the case 1. Further, in the vicinity of the handle insertion hole 29 inside the case 1, a frame 1 having a bearing hole 12e for receiving both ends of the handle shaft 8 pivotally supporting the handle 2 is provided.
Two are provided. The frame 12 is formed of a metal plate, and as shown in FIG. 5, a pair of side pieces 12a, 12a having substantially the same shape.
And a connecting piece 12 for connecting both side pieces 12a, 12a at an edge.
b, and a fixed piece 12c protruding outward from the lower edge of each side piece 12a, 12a. Screw hole 1 in the fixing piece 12c
2d is formed and the partition wall 2 on the bottom surface of the body 1a is formed.
Mounting stand protruding from the extension line of 8 in the longitudinal direction (not shown)
It is fixed by screwing on. The handle 2 is made of a synthetic resin molded product, has an operating portion 2a protruding to the front surface of the case 1 through the handle insertion hole 29, and a bearing portion 2c for receiving the handle shaft 8 is provided on the rear surface of the operating portion 2a. Link bearing portion 2 protruding below the bearing portion 2c
b is provided. The operation unit 2a and the link bearing unit 2
The protruding directions are set so that they are not in a straight line with b and have a substantially V shape. Thus, the both ends of the handle shaft 8 inserted through the bearing portion 2c are connected to both side pieces 12 of the frame 12.
The handle 2 is rotatably attached to the frame 12 by being inserted into the bearing holes 12e and 12e provided in the a and 12a. That is, in the handle 2, between the position where the operation portion 2a is substantially flush with the opening surface of the handle insertion hole 29 (see FIG. 8) and the position where the operation portion 2a projects from the handle insertion hole 29 (see FIG. 9). Then, the handle shaft 8 is rotated as a fulcrum so that it can be raised and lowered. Here, the handle return spring 1 made of scissor-shaped springs is provided around the bearing 2c of the handle 2.
6 is mounted, and a locking piece 16a provided at one end of the handle return spring 16 is hooked and locked in a hooking groove 12j formed in one side piece 12a of the frame 12. The handle 2 is biased by the spring force in a direction in which the operating portion 2a stands up from the front surface of the case 1.

By the way, as shown in FIG. 2, from the side wall 70b on the upper side of the cover 1b, insulating walls 71, 71 which are abutted against the insulating walls 35, 35 of the body 1a are provided so as to project outward. In addition, a pair of auxiliary partition walls 72, 72 facing each other in the width direction (left and right direction in FIG. 2) are provided inside the cover 1b so as to project from the side wall 70b above the cover 1b to the front wall 70a. Further, the auxiliary partition 72 at the center of the front wall 70a,
A rectangular handle insertion hole 29 is opened in a region sandwiched by the 72, and a handle shaft 8 disposed between the auxiliary partition walls 72, 72 is provided in a portion desired by the handle insertion hole 29 on the opposing surface of the auxiliary partition walls 72, 72. Locking parts 73, 7 for locking the ends of the
3 are provided respectively. The locking portions 73, 73 are provided so as to project in the longitudinal direction of the auxiliary partition walls 72, 72 so that the amount of protrusion increases from the back surface (opening surface) side of the cover 1b toward the front wall 70a side, and on the surfaces facing each other. Slope 73
a and 73a are formed.

When the cover 1b is attached to the body 1a, the cover 1b is pressed against the front surface of the body 1a by inserting the operating portion 2a of the handle 2 into the handle insertion hole 29. A direction in which both ends of the handle shaft 8 protruding from the hole 12e are in sliding contact with the inclined surfaces 73a, 73a of the locking portions 73, 73, and the auxiliary partition walls 72, 72 on which the locking portions 73, 73 project are separated from each other. Since it bends in the width direction of the cover 1b, the end portion of the handle shaft 8 eventually gets over the locking portion 73, and the locking portion 73 moves.
Will be locked at the end of the (see FIG. 1). That is,
By locking the locking portions 73, 73 to the end of the handle shaft 8, the body 1a and the cover 1b can be temporarily fixed.
Therefore, even if the body 1a and the cover 1b are not fixed with screws or the like, the cover 1b is prevented from rising from the body 1a, the handle 2 hits the periphery of the handle insertion hole 29 of the cover 1b, and the main contact 26 of the main circuit is inadvertently contacted. It is possible to eliminate the risk of being in an open state and to easily perform a characteristic test as compared with the conventional example. Also, cover 1b to body 1
By pulling in the direction away from a, the end of the handle shaft 8 and the locking portion 72 can be released from the locked state, and the body 1a and the cover 1b can be easily separated, so it is necessary according to the result of the characteristic test. The characteristic adjustment work can be performed more easily than the conventional example. In addition, the locking portion 73 is connected to the pair of auxiliary partition walls 7.
The cover 1b can be temporarily fixed to the body 1a in a stable state because they are provided on the handlebar shaft 8 and the handlebar shaft 8 respectively. Also,
If the cover 1b is made of a thermoplastic resin, the auxiliary partition walls 72, 72 integrally formed with the cover 1b are easily elastically deformed, and the locking portion 73 can be easily locked to the end of the handle shaft 8. You can Further, in the present embodiment, as shown in FIG. 2, the upper end portions of the auxiliary partition walls 72, 72 are connected via the front wall 70b, whereas the lower end portions of the auxiliary partition walls 72, 72 are not connected, The vicinity of the lower end portions of the auxiliary partition walls 72, 72 provided with the locking portion 73 is easily bent to facilitate the attachment / detachment of the cover 1b with respect to the body 1a.

The opening / closing mechanism 5 includes a handle link 11, a latch plate 13, and a movable frame 17. Handle link 11
Is a pair of substantially strip-shaped leg pieces 11c, 1 as shown in FIG.
1c and a cylindrical driving shaft 11b bridged at the lower ends of the leg pieces 11c and 11c, a connecting piece 11d that connects the leg pieces 11c and 11c, and a link bearing portion 2b of the handle 2.
Link bearing holes 11a, 11a through which both ends of the link shaft 36 inserted through the shaft hole are formed at the upper ends of the leg pieces 11c, 11c. Link bearing holes 11a, 11
Both ends of the link shaft 36 protruding from the a to the outside of the leg pieces 11c, 11c are the side pieces 12a, 12a of the frame 12.
It is inserted and locked in guide grooves 12f, 12f formed in the downwardly curved arcuate shape, and the movement range of the handle link 11 is restricted by these guide grooves 12f, 12f.

The latch plate 13 has a latch piece 13a formed in a substantially V shape, and a pair of arm pieces 13b, 13b projecting from both sides of the upper end of the latch piece 13a in the same direction.
A semi-circular bearing groove 1 is formed at the tip of the arm pieces 13b, 13b.
3c and 13c are formed, and shaft projections 12g and 12g are provided on the opposite surfaces of the both side pieces 12a of the frame 12 so as to project.
Is supported by the bearing grooves 13c, 13c, the latch plate 13 is rotatably attached to the frame 12. The drive shaft 11b of the handle link 11 is brought into contact with the central front end of the latch plate 13 and the movable frame 17 (see FIG. 8).

Further, as shown in FIG. 6, the movable frame 17 is made of a synthetic resin molded product having an insulating property, and the three movable contacts 25, 25, 25 are inserted into and locked by the locking groove 17, respectively.
a is provided side by side, and both ends of the case 1 are locked in the partition wall 27 of the case 1 and a groove portion 14 formed in the inner wall surface facing the partition wall 27 along the front-rear direction (direction perpendicular to the paper surface of FIG. 3). It is housed in the case 1 so as to be movable in the front-back direction (vertical direction in FIG. 8). On the other hand, the movable contact 25,
25, 25, the end opposite to the movable contact 22 is the body 1
A part which is locked by a locking piece 18 protruding from the inner bottom surface and is located between a part of the movable frame 17 which is locked in the locking groove 17a and an end which is locked by the locking piece 18. Is a coil spring 19
It is urged forward of the case 1 by. The coil spring 19 has one end inserted into a protrusion 20 protruding between the groove 14 on the inner bottom surface of the body 1a and the locking piece 18,
The other end is in contact with the movable contact 25.

As shown in FIGS. 5 and 8, the trip member 60 has a base piece 60a which is disposed along the left-right width direction of the case 1 so as to straddle the three movable contacts 25, 25, 25,
A substantially L-shaped leg piece 60b protruding downward from an end of the base piece 60a at a substantially central portion in the longitudinal direction, and a substantially triangular driving piece protruding laterally from the vicinity of both longitudinal end portions of the base piece 60a. 60
c, 60e, and first and second projections projecting from the tip end of each drive piece 60c, 60e substantially parallel to the longitudinal direction of the base piece 60a.
The engaging portions 60d and 60f are integrally formed of synthetic resin. In addition, the turning shaft 3 is provided at the bent portion of the leg piece 60b.
A bearing portion 60g having a bearing hole through which 7 is inserted is formed, and the end portions of the rotating shaft 37 protruding from both ends of the bearing portion 60g are inserted into the bearing holes 12i, 12i formed in both side pieces 12a of the frame 12. By supporting each, the trip plate 60 is rotatably attached to the frame 12. Here, a tripping member return spring 61 made of scissors-shaped springs is mounted on the outer periphery of the bearing portion 60g, and a locking piece 61a provided at one end of the tripping member return spring 61 has one side piece of the frame 12. The tripping member 60 is urged in the direction (clockwise in FIG. 8) in which the leg piece 60b approaches the latch plate 13 by the spring force of the tripping member return spring 61.

Then, as shown in FIG. 9, when the handle 2 is rotated so that the operating portion 2a is turned down from the state where the main contact 26 is opened (open state), the link bearing portion 2b moves toward the latch plate 13. The handle link 11 rotates in a clockwise direction in FIG. 9 about the link shaft 36 as a fulcrum. With the rotation of the handle link 11, the drive shaft 11b of the handle link 11 moves in a direction approaching the movable contact 25 (downward in FIG. 8) while slidingly contacting the latch piece 13a of the latch plate 13, and the coil spring 19 The movable contact 25 is moved downward by pushing the movable frame 17 downward against the spring force. Then, when the link shaft 36 moves toward the latch plate 13 side (right side in FIG. 8) with respect to the straight line connecting the handle shaft 8 and the drive shaft 11b of the handle link 11, the lower end portion of the latch plate 13 moves to the leg of the trip member 60. The handle 2 is held at a position where the operating portion 2a is substantially flush with the opening surface of the handle insertion hole 29 because it abuts against the tip of the piece 60b and is latched. At this time, since the movable frame 17 is pressed downward by the drive shaft 11b of the handle link 11, the three movable contacts 25, 25, 25 locked in the locking groove 17a of the movable frame 17 are also driven downward. Then, as shown in FIG. 8, the movable contacts 22 fixed to the tip ends of the movable contacts 25 face the fixed contacts 2 facing each other.
The main contact 26 is brought into contact with 1 and the main contact 26 is closed (closed state). Contrary to the above description, when the handle 2 is rotated from the closed state shown in FIG. 8 in the direction in which the operating portion 2a is erected, the drive shaft 11b of the handle link 11 is moved forward and the spring of the coil spring 19 is moved. Since the movable frame 17 moves upward due to the force, the movable contact 22 separates from the fixed contact 21 to open the main contact 26, and the open state shown in FIG. 9 is obtained. As shown in FIG. 5, the operating portion 2a of the handle 2 is provided with a protrusion 2d projecting from approximately the center on one end side. When the main contact 26 is opened, the upper end of the latch piece 13a of the latch plate 13 is opened. The protrusion 2d contacts the edge (see FIG. 9), and the rotation of the latch plate 13 is restricted.

The opening / closing mechanism section 5 constructed as described above is
In the closed state of the main contact 26, if a leakage current flows in the main circuit, the first electromagnetic release device 9A operates, and if a neutral phase is lost, the second electromagnetic release device 9B operates to cause a short circuit. If an abnormal current such as a current or an overload current flows, the trip devices 6 and 6 are actuated to drive the trip member 60 to release the latched state of the latch plate 13 and forcibly open the main contact 26. To function.

As shown in FIG. 6, the first electromagnetic release device 9A is moved by the output of the leakage protection circuit 50 to be excited by the first electromagnet, and the excited first electromagnet is moved to be latched. And a first plunger 93A for driving the trip member 60 so as to release the latched state of the plate 13. The first electromagnet is a coil 90 that is energized by being energized by the output of the leakage protection circuit 50, and a coil frame 91 that is formed of an insulating material in a tubular shape having openings at both ends and has the coil 90 wound on the outside. And a yoke 92 formed in a substantially U-shape that is opened upward by a magnetic body, and the first plunger 93A is inserted into the coil frame 91 so as to be retractable. The coil frame 91 is formed in a rectangular tube shape having outer flanges 91a and 91b at both ends in the axial direction, and the coil 90 is provided at both ends in the direction orthogonal to the axial direction of one outer flange 91b.
Coil terminals 91c, 91c for connecting the terminals are planted, and these terminals 91c, 91c are leakage protection circuit 5
Connected to 0. In the leakage protection circuit 50, as will be described later, when the output of the secondary winding of the zero-phase current transformer CT exceeds a predetermined level, the coil 90 is energized and excited. Also, the coil frame 9
A protrusion 95 is integrally formed with the coil frame 91 on the right side of the outer flange 91b of FIG. The protrusion 95 supports a stopper member insertion hole 95a through which a first stopper member 94A described later is inserted so as to be vertically movable, and a support base 95b that supports a fixed contact plate 96 that constitutes a test switch.
And the inside communicates with the internal cavity of the coil frame 91 and the end is opened. In addition, a support base 95b for the protrusion 95
A fixed contact plate 96 is supported by the fixed contact plate 96, and a base end portion 97a of a movable contact plate 97 formed by bending a strip-shaped conductive member into a substantially V shape is fixed. 9
7b and the fixed contact plate 96 face each other so that they can come into contact with and separate from each other. Thus, the fixed contact plate 96 and the movable contact plate 97 constitute a test switch SW, and the test button 42 will be described later.
Contact portion 9 of the movable contact plate 97 bent by the pushing operation of
7b comes into contact with the fixed contact plate 96 to conduct the test switch S.
When W turns on, the test circuit 52 operates and the zero-phase current transformer CT
An unbalanced current is made to flow to create a pseudo-leakage state.

The first stopper member 94A is formed of a synthetic resin into a rectangular flat plate shape, and has a first central portion as shown in FIG.
The main body 94a is provided with an insertion window 94c through which the plunger 93A is inserted, and an arm portion 94b vertically extending downward from a corner portion on one end side of the main body 94a and having an engaging projection 94d protruding from a tip portion thereof. Further, a mounting projection 94e that projects downward in FIG. 6 is formed from the inner peripheral surface of the main body 94a in front of the insertion window 94c. Then, the mounting protrusion 94e is fitted and attached to one end of the stopper member return spring 98 formed of a coil spring, and the first stopper member 94A is inserted into the stopper member insertion hole 95a of the protrusion 95 from the side of the arm portion 94b. Is inserted, the other end of the stopper member return spring 98 is locked by the locking step 95c formed on the inner wall surface of the stopper member insertion hole 95a, and the stopper member return spring 98 urges the stopper member return spring 98 in the opposite insertion direction. The first stopper member 94A is brought into contact with the projection 9
It is attached to 5.

The first plunger 93A is formed by bending a metal plate having magnetism to open downward as shown in FIG. 6, and a main portion 93a having a substantially U-shaped cross section and an outer side of a right end surface of the main portion 93a. Leg pieces 93b, 93b that open in a substantially C-shape
And are integrally formed. Here, one leg 93b
The driving piece 93c is integrally formed at the lower end by bending the hook into a hook shape. Then, the left end of the main portion 93a inserted in the plunger return spring 99 formed of a coil spring passes through the opening of the projection 95 and the insertion window 94c of the first stopper member 94A attached to the projection 95. Coil frame 91
The first plunger 93A can be retracted from the opening on the right end side of the coil frame 91 through the opening of the projection 95 by being inserted into the inside of the coil frame 91. Here, as shown in FIG. 12, the inside of the protrusion 95 is composed of a large-diameter portion on the opening side and a small-diameter portion on the coil frame 91 side, and the plunger return spring 99 inserted from the opening into the large-diameter portion has a small-diameter portion. The opening edge and the first
Is interposed in a compressed state between the leg pieces 93b and 93b of the plunger 93A of
The plunger 93A is urged in the direction opposite to the insertion direction into the coil frame 91. Further, the first stopper member 94A includes the main body 9
The peripheral edge portion 94f behind the insertion window 94c of 4a abuts on the open end edge of the main portion 93a of the first plunger 93A to prevent the stopper member insertion hole 95a from coming off.

As shown in FIG. 6, the yoke 92 is formed on both side pieces 9.
2a and 92a are the outer collar 91 along the axial direction of the coil 90.
It is attached to the rear side of the coil frame 91 so as to abut the a and 91a. Here, a relief groove 92b for escaping the first plunger 93A is formed in the side piece 92a on the right end side, and the first plunger 93A is inserted into the coil frame 91 through the relief groove 92b. The side piece 92a on the left end side is formed to have a size to cover an opening on the upper end side of the coil frame 91 by about half, and the first piece is formed through this opening.
The left end portion of the plunger 93A and the side piece 92a on the left end side of the yoke 92 are opposed to each other.

By the way, the leakage indicator member 100A is attached to the upper end of the first plunger 93A through the connecting portion 101. The earth leakage display member 100 slides between the earth leakage display position and the non-leakage display position in association with the first plunger 93A as described later, and is formed of a non-magnetic material into a rectangular plate shape. On the right side portion, characters (for example, two characters “leakage”) indicating the leakage state are displayed by an appropriate method such as printing. In addition, from the center of the left end edge of the earth leakage display member 100, a substantially L-shaped connecting portion 10
1 is integrally formed, and the earth leakage display member 100 and the connecting portion 101 are generally U-shaped. Connecting part 10
1 is a width dimension that can be inserted into the inside of the coil frame 91,
The fixed portion 1 fixed to the first plunger 93A is provided at the tip.
02 is integrally formed. The fixed portion 102 is narrower than the connecting portion 101 and has a bifurcated distal end,
Engaging claws 102a, 102a are provided on both edges so as to project. On the other hand, from the left end edge of the main portion 93 of the first plunger 93A, three mounting claws 93d, 93d, 93d for sandwiching the fixed part 102 from the front-rear direction are projected, and the engaging claw 102a of the fixed part 102 is provided. , 102a are formed in the upper part of the main part 93a.

Thus, as shown in FIG. 12, the leakage indicator member 100 is positioned in front of the coil frame 91, and the opening edge on the left end side of the coil frame 91 and the tip edge of the side piece 92a of the yoke 92 are formed. The fixing portion 102 and the connecting portion 101 are inserted into the coil frame 91 through the gaps, the fixing portion 102 is held by the mounting claws 93d, 93d, 93d of the first plunger 93A and the engaging claws 102a, 102a are engaged. Grooves 93e, 93
The fixed part 102 is engaged with the first plunger 9 by engaging with e.
It is fixed to 3A in a retaining state. As a result, the connecting portion 101 protruding from the opening on the left end side of the coil frame 91 has the outer collar 9
It is folded back to the front side of the coil frame 91 so as to straddle 1a,
The earth leakage display member 100 is arranged substantially parallel to the front surface of the coil frame 91. However, when the first plunger 93A moves in the direction of coming out of the inside of the coil frame 91, the connecting portion 101 causes the outer collar 9 of the coil frame 91 to move as shown in FIG.
The first plunger 93A is prevented from coming off by coming into contact with 1a.

As shown in FIG. 6, the second electromagnetic release device 9B and the second stopper member 94B are respectively the first electromagnetic release device 9A and the first stopper member 94A.
Since it has the same configuration as the above, the same components are designated by the same reference numerals and the description thereof will be omitted. Further, the open-phase display member 110 has the same configuration as the leakage display member 100, and the second phase display member 110 will be described later.
It is slidably moved between the open phase display position and the non-open phase display position in conjunction with the plunger 93B, and is attached to the left end portion of the second plunger 93B via the connecting portion 111. The open-phase display member 110 is formed of a non-magnetic material in the shape of a rectangular plate, and characters indicating the open-phase state (for example, two characters of “open phase”) are displayed on the right side portion of the front surface by an appropriate method such as printing. There is.

On the other hand, as shown in FIG. 6, the movable frame 17 has a first stopper member 94A and a second stopper member 9 attached thereto.
Grooves 17b and 17d into which the arm portions 94b and 94b of 4B are inserted so that they can move back and forth respectively are formed, and the groove 1
Engagement protrusions 17c, 17e are formed at the front ends of the arms 7b, 17d to prevent the engagement protrusions 94d, 94d at the tips of the arms 94b, 94b from engaging with each other and preventing them from coming off.

The first electromagnetic release device 9A and the earth leakage display member 100, and the second electromagnetic release device 9B and the open-phase display member 110 configured as described above are formed in the case 1 as shown in FIG. Of the three created spaces, they are respectively arranged in spaces on both ends which are not adjacent to each other (spaces in which the poles connected to the voltage lines are housed). At this time, as shown in FIG. 4, the leakage display member 100 faces the display window 40A formed on the front surface of the case 1 (cover 1b), and the open phase display member 1
10 also faces the display window 40B formed on the front surface of the case 1 (cover 1b), and the test switch SW
The movable contact plate 97, which constitutes the above, faces the test button 42, which is disposed so as to be freely pushed into the front surface of the case 1 (cover 1b). Here, the two display windows 40A and 40B are arranged at substantially the same position on the front surface of the case 1 in the direction (vertical direction in FIG. 4) substantially orthogonal to the parallel direction of the three poles (the width direction of the case 1), that is, the case. Each display window 40A from the lower end of 1,
Since the openings are formed at positions where the distance to the lower edge of 40B is substantially equal, the appearance of the case 1 viewed from the front is improved.

FIG. 7 shows a circuit diagram of an earth leakage protection circuit 50 for driving the first electromagnetic release device 9A, an open phase protection circuit 51 for driving the second electromagnetic release device 9B, and a test circuit 52 for earth leakage test. ing. In the leakage protection circuit 50, the output of the secondary winding of the zero-phase current transformer CT is converted into a voltage and input to the detection terminal of the leakage protection IC 50a, and the leakage current flows, so that the input voltage of the detection terminal is at a predetermined level. When it exceeds, leakage detection is performed by the leakage protection IC 50a, and a leakage detection signal is output from the output terminal. The leakage detection signal turns on the thyristor SCR1 to apply an exciting current to the coil 90 of the first electromagnetic release device 9A. The main contact 26 is opened to protect the load. Further, the test circuit 52 includes a lead switch Lx that is inserted between the two input terminals T1 and T2 connected to the voltage pole, the normally open test switch SW, the resistor RT, and the through hole of the toroidal core of the zero-phase current transformer CT. When the test switch SW is turned on, a current is caused to flow through the lead wire Lx so that an unbalanced current is caused to flow through the zero-phase current transformer CT to create a pseudo electric leakage state.

On the other hand, in the open phase protection circuit 51, the input terminal T
1, the input voltage from T2 is full-wave rectified by the diode bridge DB and input to the open-phase protection IC 51a, and the detection line Ln from the input terminal T3 connected to the neutral line is connected between the input terminals T1 and T2. Connected voltage dividing resistors R8 and R9
Is connected to the voltage dividing point of
6, R12, and R13 are connected to the detection terminal of the open-phase protection IC 51a. As for the voltage of the detection terminal, a pulsating current voltage with uniform amplitude appears when the power supply and the load are properly connected, but if the neutral wire is broken and a phase break occurs, the voltage of the two voltage wires When the potential of this detection terminal exceeds a predetermined level due to the voltage division ratio due to the load of each phase, and the potential of this detection terminal exceeds a predetermined level, the open-phase protection IC 51a detects the open-phase and outputs the open-phase detection signal. Then, the thyristor SCR2 is turned on by this open phase detection signal, an exciting current is passed through the coil 90 of the second electromagnetic release device 9B to open the main contact 26, and the load is protected. The leakage protection circuit 50, the open-phase protection circuit 51, and the test circuit 52 are provided on a rectangular flat printed board 53 for leakage protection I.
It is configured by mounting circuit components such as the C50a and the open-phase protection IC 51a, and is housed inside the case 1 as shown in FIGS.

Next, the operation of the first electromagnetic release device 9A constructed as described above will be described. First, in a normal state in which the leakage current does not flow in the main circuit, as shown in FIG. 11, since the unbalanced current does not flow in the secondary side of the zero-phase current transformer CT, the leakage protection circuit 50 energizes the coil 90. Therefore, since the coil 90 is not excited, the plunger return spring 9
The first plunger 93A projects from the inside of the coil frame 91 by the spring force of 9 and stops at the position where the connecting portion 101 contacts the outer flange 91a of the coil frame 91. At this time, the movable frame 17 is pushed down by the handle link 11 and moves downward in FIG. 11 to close the main contact 26. Also, the first
The stopper member 94A of is the engaging projection 94d of the arm portion 94b.
Is engaged with the engaging protrusion 17c of the movable frame 17, and therefore is pulled downward as the movable frame 17 moves. In this state (normal state), the first plunger 93A
The drive piece 93c is inserted into a groove 60h provided in the base piece 60a of the trip member 60 so as not to interfere with the trip member 60. At this time, the earth leakage display member 100 connected to the first plunger 93A by the connecting portion 101 is at one end position (the right end position in FIG. 11) of the movement range that is the non-leakage display position, and the front surface of the case 1 In the display window 40A provided on the front side, a left side portion of the front surface of the leakage display member 100, that is, a portion where no characters indicating the leakage state are written, is displayed, and it is displayed through the display window 40A that it is in a non-leakage state (normal state). It

On the other hand, when a ground fault occurs, the zero-phase current transformer CT
If an unbalanced current flows to the secondary side of the above, the coil 90 of the first electromagnetic release device 9A is energized by the output of the leakage protection circuit 50 as described above. When the coil 90 is excited by energization, an attractive force acts on the first plunger 93A so as to reduce the magnetic resistance of the magnetic path passing through the coil 90, the first plunger 93A and the yoke 92, and the plunger return spring 99. The first plunger 93A is pulled inside the coil frame 91 against the spring force of and moves to the left in FIG. When the first plunger 93A moves to the left, the drive piece 93c of the first plunger 93A engages with the first engaging portion 60d of the trip member 60, and the first engaging portion 6c.
A leftward force in FIG. 11 is applied to the drive piece 60c on which 0d is projected. This leftward force causes the trip member 60 to rotate counterclockwise in FIG. 11 against the spring force of the trip member return spring 61, so that the leg piece 60b of the trip member 60 and the tip portion of the latch plate 13 are separated from each other. Is released. Then, as shown in FIG. 10, the handle link 11, which is no longer supported by the latch plate 13, moves toward the latch plate 13 (to the right in FIGS. 10 and 11), and the link shaft 36 causes the handle shaft 8 and the handle link 11 to move.
The movable frame 17 side (see FIG.
The handle return spring 1
The handle 2 is rotated in the upright direction (clockwise in FIG. 10) by the spring force of 6, and the drive shaft 11b of the handle link 11 is moved leftward in FIG. 10 accordingly. Therefore, the pressing force applied to the movable frame 17 by the handle link 11 does not act, and the movable contact 25 and the movable frame 17 also move upward in FIG. 10 by the spring force of the coil spring 19 to force the main contact 26. Is opened (tripped) (see FIG. 12). Further, by moving the movable frame 17 upward, the engagement protrusion 94d of the arm portion 94b and the movable frame 1 are moved.
7 is disengaged from the engaging protrusion 17c, and the first stopper member 94A is moved upward by the spring force of the stopper member return spring 98, so that the main body 94a of the first stopper member 94A.
The peripheral portion 94f is the main portion 93a of the first plunger 93A.
It engages with a groove-shaped engaging portion 93f formed on the lower end side. At this time, with the rightward movement of the first plunger 93A, the earth leakage display member 100 moves to the other end position (the left end position in FIG. 12) of the movement range that is the earth leakage display position, and the front surface of the case 1 The leakage display member 10 is displayed on the display window 40A.
The front right part of 0, that is, the portion in which the character indicating the leakage state is written, faces, and it is displayed through the display window 40A that the leakage state is present. The display window 40A is fitted with a lens 41 for enlarging the characters of the leakage display so that the characters of the leakage display can be easily seen.

On the other hand, if the main contact 26 is opened, an unbalanced current will not flow to the secondary side of the zero-phase current transformer CT, the current supply by the leakage protection circuit 50 will stop, and the coil 90 will not be excited. 12, the attraction force does not act on the plunger 93A, and the spring force of the plunger return spring 99 tries to move the first plunger 93A to the right in FIG. 12, but as described above, the main body 94 of the first stopper member 94A.
The peripheral portion 94f of a is the main portion 93 of the first plunger 93A.
Since it engages with the engaging portion 93f formed on the lower end side of the a, the movement of the first plunger 93A is restricted to a short distance by the first stopper member 94A as shown in FIG. Stops at the leakage display position.
Here, when the first plunger 93A moves slightly to the right due to the opening of the main contact 26 as described above, the leftward force by the driving piece 93c of the first plunger 93A is driven by the driving piece 60c of the trip member 60. Therefore, the tripping member 60 is rotated clockwise by the spring force of the tripping member return spring 61 to return to its original position.
In other words, the thickness (diameter dimension) t1 of the first engaging portion 60d is set so that the trip member 60 can return to the original position after the main contact 26 is forcibly opened by detecting the electric leakage. is there. Then, as described above, if the reset operation for closing the main contact 26 by operating the handle 2 is performed,
The downward movement of the movable frame 17 causes the engagement protrusion 94d of the arm portion 94b and the engagement protrusion 17c of the movable frame 17 to engage with each other, and resists the spring force of the stopper member return spring 98 to cause the first stopper member. 94A moves downward to move the first stopper member 94
The peripheral portion 94f of the main body 94a of A and the first plunger 93
The engagement with the engaging portion 93f of A is released, and the spring force of the plunger return spring 99 moves the first plunger 93A to the right to return to the closed state of FIG.

Next, the operation of the second electromagnetic release device 9B will be described. First, in a normal state in which the phase loss of the neutral wire does not occur, the open phase protection circuit 51 does not energize the coil 90 as shown in FIG. 14, and the coil 90 is not excited. The second plunger 93B projects from the inside of the coil frame 91 by the force, and stops at the position where the connecting portion 101 contacts the outer flange 91a of the coil frame 91. At this time, the movable frame 17 has the handle link 11
It is pushed down to move downward in FIG. 14 to close the main contact 26. Further, in the second stopper member 94B, the engagement protrusion 94d of the arm portion 94b has the engagement protrusion 17 of the movable frame 17.
Since it is engaged with e, it is pulled downward in accordance with the movement of the movable frame 17. In this state (normal state), the driving piece 93c of the first plunger 93B is inserted into the recess 60i provided in the base piece 60a of the trip member 60 so as not to interfere with the trip member 60. At this time, the open-phase display member 110 connected to the second plunger 93B by the connecting portion 101 is at one end position (the right end position in FIG. 14) of the movement range that is the non-open-phase display position, and the case 1 Window 40B provided on the front of the
The front left side portion of the open phase display member 110, that is, a portion where no characters indicating the open phase state are written, faces the display window 4
It is displayed through 0B that the state is the non-phase loss state (normal state).

On the other hand, if the neutral wire is out of phase, the coil 90 of the second electromagnetic release device 9B is energized by the output of the open phase protection circuit 51 as described above. Coil 90 by energizing
Is excited, coil 90-second plunger 93B
-Attracting force acts on the second plunger 93B so as to reduce the magnetic resistance of the magnetic path passing through the yoke 92, and the second plunger 9 is resisted against the spring force of the plunger return spring 99.
3B is drawn inside the coil frame 91 and moves to the left in FIG. When the second plunger 93B moves to the left, the driving piece 93c of the second plunger 93B engages with the second engaging portion 60f of the trip member 60, and the second engaging portion 60f is provided so as to project. The leftward force in FIG. 14 is applied to the driving piece 60e that is moving. This leftward force causes the trip member 60 to rotate counterclockwise in FIG. 14 against the spring force of the trip member return spring 61, so that the leg piece 60b of the trip member 60 and the tip portion of the latch plate 13 are released. Is released. Then, as in the case of the first electromagnetic release device 9A, the pressing force on the movable frame 17 by the handle link 11 does not act, and the movable contact 25 and the movable frame 17 are also moved by the spring force of the coil spring 19 in FIG. , And the main contact 26 is forcibly opened (tripped) (see FIG. 15). Further, by the upward movement of the movable frame 17, the engagement protrusion 94d of the arm portion 94b and the engagement protrusion 17e of the movable frame 17 are disengaged, and the stopper member return spring 9 is released.
The second stopper member 94B is moved upward by the spring force of 8, and the peripheral edge portion 94f of the main body 94a of the second stopper member 94B is a concave groove formed on the lower end side of the main portion 93a of the second plunger 93B. Engages with the engaging portion 93f. At this time, with the rightward movement of the second plunger 93B, the open phase display member 110 moves to the other end position (the left end position in FIG. 15) of the moving range that is the open phase display position,
The display window 40B on the front surface of the case 1 faces a right side portion of the front surface of the open phase display member 110, that is, a portion on which characters indicating the open phase state are written, and the open phase state is displayed through the display window 40B. It should be noted that the display window 40B is also fitted with a lens 41 for enlarging the characters in the open phase display, so that the characters in the open phase display are easy to see.

On the other hand, when the main contact 26 is opened, the energization by the open-phase protection circuit 51 is stopped, the coil 90 is no longer excited, and the attractive force does not act on the second plunger 93B.
Although the second plunger 93B tries to move to the right in FIG. 15 due to the spring force of the plunger return spring 99, the peripheral edge portion 94f of the main body 94a of the second stopper member 94B does not move like the first electromagnetic release device 9A. Engagement portion 9 formed on the lower end side of the main portion 93a of the second plunger 93B
Since it engages with 3f, the movement of the second plunger 93B is restricted to a short distance by the second stopper member 94B as shown in FIG. 16, and the open phase display member 110 stands still at the open phase display position. However, even if the second plunger 93B moves slightly to the right due to the opening of the main contact 26 as described above, the leftward force by the driving piece 93c of the second plunger 93B is driven by the driving piece of the trip member 60. The trip member 60 cannot return to its original position because the trip member 60 is still acting on 60e. In other words, the thickness t2 of the second engaging portion 60f is set so that the trip member 60 cannot return to its original position after the main contact 26 is forcibly opened by detecting the open phase (t1). <T2). Thus, in this case, even if the handle 2 is operated, the engaging protrusion 94d of the arm portion 94b
And the engaging protrusion 17e of the movable frame 17 do not engage with each other, and the forced opening of the main contact 26 due to the phase loss detection cannot be reset. That is, if the handle 2 is operated to close the main contact 26 when the load is unbalanced due to a phase loss, an overvoltage may be applied to the load and the load may fail. In the embodiment, the second stopper member 94B
When the return of the second plunger 93B is prevented by the second plunger 93B, the latch member 13
Since the tripping member 60 is held at a position where it does not latch, the main contact 26 does not close even if the handle 2 is operated, and it is possible to prevent an overvoltage from being applied to the load.

On the other hand, when the main contact 26 is forcibly opened by the second electromagnetic release device 9B, resetting is performed as follows. That is, a thin rod-shaped jig is inserted from the reset hole 43 penetrating the front surface of the case 1 (cover 1b) facing the second stopper member 94B, and the tip of the jig inserts the main body 94a of the second stopper member 94B. If the second stopper member 94B is moved downward in FIG. 16 against the spring force of the stopper member return spring 98 by pressing the upper portion, the main body 94 of the second stopper member 94B will be described.
a peripheral edge portion 94f of a and the engaging portion 9 of the second plunger 93B
The engagement with 3f is released, the second plunger 93B moves to the right by the spring force of the plunger return spring 99, and the second electromagnetic release device 9B returns to the normal state. As a result, the leftward force by the drive piece 93c of the second plunger 93B does not act on the drive piece 60e of the trip member 60, so that the trip member 60 is moved to the timepiece shown in FIG. It rotates around and returns to the original position as shown in FIG. Then, in this state, if the reset operation of operating the handle 2 to close the main contact 26 is performed, the main contact 26 shown in FIG. 14 can be returned to the closed state.

[0041]

According to the first aspect of the present invention, a body is formed in a box shape having an opening on the front surface and accommodates the respective poles of the main circuit in a plurality of internal spaces divided by a plurality of partition walls, and a front surface of the body. Side cover, a handle at least a part of which is exposed through a handle insertion hole provided on the front surface of the cover, a handle shaft that is attached to the handle and serves as a rotation fulcrum of the handle, and a handle attached to the body. A frame that supports the shaft, an opening and closing mechanism that opens and closes the main contact of each pole at least according to the turning operation of the handle, and the opening and closing mechanism is activated when an abnormal current flows in the main circuit to force the main circuit. And a locking means for locking the end of the handle shaft inside the cover. By locking the locking part at the end of the handle shaft, the body and the cover can be opened. Temporary Mesuru it can be, and for this reason,
Prevents the cover from rising from the body without fixing the cover to the body with screws, and facilitates characteristic testing without the risk of the handle hitting the peripheral edge of the handle insertion hole and opening the main circuit carelessly. Further, the body and the cover can be easily separated by releasing the locked state of the handle shaft end portion and the locking portion, and the characteristic adjustment work can be performed more easily than in the conventional example. .

According to a second aspect of the present invention, in the first aspect of the present invention, since a pair of engaging portions for engaging with the handle shaft are provided, the cover can be temporarily fixed to the body in a stable state. The effect is that you can do it.

According to the invention of claim 3, in the invention of claim 1 or 2, since the cover is made of thermoplastic resin, the cover is easily elastically deformed, and the engaging portion is easily engaged with the end portion of the handle shaft. The effect is that you can stop.

The invention of claim 4 is the invention of claim 1 or 2 or 3.
In the invention of claim 1, a frame is disposed between the partition walls of the body facing each other, and a plurality of auxiliary partition walls are formed inside the cover to abut against each partition wall in the state where the cover is attached to the body, and the end of the handle shaft is Since the locking portion is provided on the auxiliary partition wall facing the section, the locking portion can be easily locked to the end portion of the handle shaft by utilizing the elastic deformation of the auxiliary partition wall provided with the locking portion. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of the present invention.

FIG. 2 is a rear view of the cover in the above.

FIG. 3 is a front view showing a state in which the above cover is removed.

FIG. 4 is a front view of the above.

FIG. 5 is an exploded perspective view in which a part of the opening / closing mechanism section of the above is omitted.

FIG. 6 is an exploded perspective view of first and second electromagnetic release devices of the above.

FIG. 7 is a circuit diagram of a leakage protection circuit, an open phase protection circuit, and a test circuit of the above.

FIG. 8 is a side cross-sectional view of the same electrode when closed.

FIG. 9 is a side sectional view of the same handle when the contact is opened.

FIG. 10 is a side sectional view just before the forced opening in the above.

FIG. 11 is a side cross-sectional view of the same electrode at the time of closing.

FIG. 12 is a side cross-sectional view at the moment when the electrodes are forcibly opened by detecting the electric leakage.

FIG. 13 is a side sectional view after forcibly opening the electrodes by detecting the electric leakage.

FIG. 14 is a side cross-sectional view of the same electrode at the time of closing.

FIG. 15 is a side cross-sectional view at the moment when the electrodes are forcibly opened by detecting the open phase.

FIG. 16 is a side cross-sectional view after forcedly opening the electrodes by detecting the open phase of the above.

FIG. 17 is a side cross-sectional view when the second electromagnetic release device of the above is reset.

[Explanation of symbols]

1a body 1b cover 2 handles 8 handle shaft 12 frames 72 Auxiliary bulkhead 73 Locking part

Claims (4)

[Claims] 1. A body, which is formed in a box shape having an opening on the front surface, accommodates each pole of the main circuit in a plurality of internal spaces partitioned by a plurality of partition walls, and a cover attached to the front surface side of the body. And a handle at least a part of which is exposed through a handle insertion hole provided on the front surface of the cover,
A handle shaft that is attached to the handle and serves as a rotation fulcrum of the handle, a frame that is attached to the body and pivotally supports the handle shaft, and an opening / closing mechanism that opens and closes the main contact of each pole in accordance with at least the rotation operation of the handle. , With a tripping device for forcibly opening the main circuit by activating the opening / closing mechanism when an abnormal current flows in the main circuit, and providing a locking portion inside the cover for locking with the end of the handle shaft A circuit breaker characterized by that. 2. The circuit breaker according to claim 1, wherein a pair of locking portions for locking each of the both ends of the handle shaft are provided. 3. The circuit breaker according to claim 1, wherein the cover is made of a thermoplastic resin. 4. A frame is disposed between the partition walls of the bodies facing each other, and a plurality of auxiliary partition walls are formed inside the cover so as to abut against each partition wall with the cover attached to the body. The circuit breaker according to claim 1, 2 or 3, wherein a locking portion is provided on the auxiliary partition wall facing the end portion.