JP2010287374A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker preventing itself from falling off due to shock of a movable contact point firmly fixed to a movable contactor in stopping the movable contactor at an open-pole terminal position. <P>SOLUTION: At a tip-side lower part of a power source side contact arm 18a constituting a movable contactor, a concave-shaped notched part 18a1 is formed with its side parts opened. The notched part is provided with a firm-fix face 18a2 firmly fixing the movable contact point 18c, and a pair of movable-contact fixing walls 18a3 erected from edge parts at a tip side and a rear-end side of the firm-fix face for preventing the movable contact point from being separated from the firm-fix face. The movable contact point is inserted into the notched part from the opening at the side part to be firmly fixed to the firm-fix face, and at the same time, a pair of side faces 18c4 facing the tip side and the rear-end side of the movable contact point are locked by the pair of movable-contact fixing walls. Furthermore, a structure of a load-side contact arm constituting the movable contactor and the movable contact point firmly fixed to the same is of the same structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  [Technical Field] The present invention relates to a circuit breaker of a two-point breaking system that cuts off an overcurrent by combining two pairs of switching contacts in series with current interrupting portions of each pole for a circuit breaker applied to a low-voltage distribution circuit.

2. Description of the Related Art A two-point circuit breaker is known in which two pairs of switching contacts are combined in series with a current interrupting portion of each pole to interrupt an overcurrent (see, for example, Patent Document 1).
FIG. 9 is a cross-sectional view showing a circuit breaker, and FIGS. 11 and 12 are views showing a state where a current breaker is turned on in a two-point circuit breaker similar to Patent Document 1. FIG. 14 is a diagram showing a current-limiting open state of the current interrupting unit.

The circuit breaker shown in FIG. 9 has a toggle link mechanism (opening / closing mechanism) 3, a current interrupting unit 4, and an overcurrent trip device 5 arranged in an insulating container composed of a case 1a and a cover 1b. An operation handle 2 for operating the link mechanism 3 is disposed so as to protrude upward from the cover 1b.
The current interrupting unit 4 is connected to the load side terminal via the first fixed contact 6 connected to the power source side terminal and the operating element of the overcurrent tripping device 5 as shown in FIGS. Second fixed contact 7 made, fixed contacts 6a, 7a fixed to the tips of the first and second fixed contacts 6, 7, and a pair of movable contacts 8c bridging the fixed contacts 6a, 7a , 8d and a movable contact 8 having an end connected to the movable contact 8, and a direction in which the movable contact 8 is separated from the fixed contacts 6a and 7a by a trip operation from the toggle link mechanism 3. Between the left and right side walls of the arc-extinguishing device 10 and the arc-extinguishing device 10 disposed in front of the opening moving path of the movable contact 8 in correspondence with the movable contact arm 9 to be rotated and the fixed contacts 6a and 7a, respectively. Are arc extinguishing grid plates 10a arranged in the upper and lower stages and the inner wall of the cover 1b. Movable contact 8 rotating to the opening end position is a stopper wall 11 abuts.

The movable contact 8 includes a power supply side contact arm 8a and a load side contact arm 8b which extend in parallel to each other from mutually opposing edges of the rectangular plate-shaped bridge portion 8e, and these power supply side contacts. Movable contacts 8c and 8d fixed to the ends of the arm 8a and the load side contact arm 8b are provided.
One end side of the movable contact arm 9 is supported by the support shaft 9a so as to be rotatable in the opening / closing direction of the movable contact 8 and the axis of the movable contact arm 9. The other end side of the movable contact arm 9 is The movable contact 8 is connected to the central portion of the bridging portion 8e. The other end of the movable contact arm 9 may be coupled to the bridging portion 8e of the movable contact 8 so as to be rotatable about the axis of the movable contact arm 9. Since the movable contact 8 is connected so as to be rotatable about the axis of the movable contact arm 9, the fixed positions of the fixed contacts 6 a and 7 a to the first and second fixed contacts 6 and 7 are processed errors. Even if it changes due to an assembly error or the like, the power contact arm 8a and the load contact arm 8b are inclined and moved in a seesaw shape, so that the contact pressure of the fixed contacts 6a and 7a and the movable contacts 8c and 8d in the applied state is increased. The balance is absorbed, and the contact stability of the fixed contacts 6a and 7a and the movable contacts 8c and 8d is achieved.

  Here, as shown in FIG. 10, the movable contact 8c fixed to the power supply side contact arm 8a is a substantially rectangular parallelepiped member, and the fixed surface 8c1 of the rectangular plane of this member is the tip of the power supply side contact arm 8a. Are fixed in a butted state to a rectangular flat fixing surface 8a1. Similarly, the movable contact 8d disposed at the tip of the load side contact arm 8b also has a rectangular flat surface to be fixed (not shown) to a rectangular flat surface to be fixed (not shown) of the load side contact arm 8b. It is fixed in the butted state.

  The overcurrent protection operation of the circuit breaker having the above configuration is such that an electromagnetic repulsive force acts between the first and second fixed contacts 6, 7 and the movable contacts 8c, 8d when an overcurrent flows in the distribution path. Then, the movable contact 8 starts to open, and the movable contacts 8c and 8d are separated from the fixed contacts 6a and 7a. At the same time, the toggle link mechanism 3 trips and moves the movable contact 8 toward the opening end position via the movable contact arm 9.

  Further, in this opening process, as shown in FIG. 14, two fixed contacts 6 a and 7 a of the first and second fixed contacts 6 and 7 and two movable contacts 8 c and 8 d of the movable contact 8 are provided. When the arcs A1 and A2 are generated and the opening operation of the movable contact 8 further proceeds, the distance between the movable contacts 8c and 8d and the fixed contacts 6a and 7a is increased, and the two arcs A1 and A2 are extended. It receives the driving force and is pushed into the arc extinguishing device 10. As a result, the arcs A1 and A2 are divided by the arc extinguishing grid plate 10a of the arc extinguishing device 10, the arc voltage increases due to the electrode drop, and the arc extinguishing grid plate 10a is also added with the cooling effect and disappears. Current limiting is interrupted.

Japanese Patent Laid-Open No. 11-273536

  By the way, in the current limiting opening process of the circuit breaker, the current path is from the first fixed contact 6 to the first fixed contact 6a, the movable contact 8c, the power supply side contact arm 8a, the load side contact arm 8b, the movable contact. Since 8d, the fixed contact 7a, and the second fixed contact 7 flow in this order, the power contact arm 8a and the load contact arm 8b of the movable contact 8 receive electromagnetic repulsion forces of different magnitudes. For this reason, as shown in FIG. 15, in the movable contact 8 that is rotatable around the axis of the movable contact arm 9, the load side contact arm 8b having a large electromagnetic repulsive force is first provided by the power side contact arm 8a. The movable contact 8 is tilted so as to be close to the stopper wall 11, and the load side contact arm 8 b comes into contact with the stopper wall 11. Next, as shown in FIG. 16, the power side contact arm 8 a is moved closer to the stopper wall 11 than the load side contact arm 8 b under the impact reaction force of the load side contact arm 8 b in contact with the stopper wall 11. The contact 8 is tilted, and the power supply side contact arm 8 a comes into contact with the stopper wall 11. As described above, in the conventional circuit breaker, the load contact arm 8b and the power contact arm 8a are alternately brought into contact with the stopper wall 11 in the current limiting process, so that the movable contact 8 swings. As shown, it receives an impact from the stopper wall 11.

Further, when a large current such as a short-circuit current flows through the distribution path, the fixed surfaces of the movable contacts 8c and 8d fixed to the tips of the power supply side contact arm 8a and the load side contact arm 8b are exposed to the arcs A1 and A2. Rises to near the melting point.
As described above, when the movable contact 8 receives an impact from the stopper wall 11 while exhibiting a swinging behavior in the current limiting opening process, the fixed surfaces of the movable contacts 8c and 8d rise to near the melting point when a large current is interrupted. The movable contacts 8c and 8d, which have a rectangular parallelepiped shape and are fixed in abutment to the tips of the power supply side contact arm 8a and the load side contact arm 8b, may fall off.

  In particular, in the small movable contact 8 in which the wall thickness of the power supply side contact arm 8a and the load side contact arm 8b is reduced, the fixing area between the power supply side contact arm 8a and the load side contact arm 8b and the movable contacts 8c and 8d is reduced. Therefore, the movable contacts 8c and 8d may drop off, and the movable contact 8d fixed to the tip of the load side contact arm 8b that first contacts the stopper wall 11 and receives a large impact reaction force is likely to drop off.

  Therefore, the present invention provides a circuit breaker that can prevent the movable contact fixed to the movable contact from dropping off due to an impact when the movable contact is stopped at the opening termination position at the time of current limiting opening. The purpose is to do.

  In order to achieve the above object, a circuit breaker of the present invention includes a first fixed contact connected to a power supply side terminal, a second fixed contact connected to a load side terminal, and the first and second A movable movable contact having a pair of movable contacts for bridging the fixed contact, and an end connected to the movable contact, and when the overcurrent occurs, the movable contact is caused by a current limiting opening operation of the switching mechanism. A rotating arm that rotates the child toward the opening end position, and a stopper that stops the rotation of the movable contact at the opening end position. A power supply side contact arm and a load side contact arm extend in the same direction from both ends, and the pair of movable contacts are respectively fixed to the front ends of the power supply side contact arm and the load side contact arm, and the bridge The part is rotatable about the axis of the rotating arm. In the circuit breaker, a concave notch having an open side is formed at the lower end of each of the power source side contact arm and the load side contact arm, and the notch secures the movable contact. A fixed surface, and a pair of movable contact fixed walls that rise from an edge on the front end side and a rear end side of the fixed surface and prevent the movable contact from separating from the fixed surface, and the movable contact Is inserted into the cutout portion from the opening of the side portion, the movable contact is fixed to the fixed surface, and a pair of side surfaces facing the front end side and the rear end side of the movable contact are connected to the pair of movable contacts. It was locked with a fixed wall.

  According to this invention, when the movable contact receives an impact from the stopper portion while exhibiting a swinging behavior at the opening end position, the movable contact inserted in the notch portions of the power source side contact arm and the load side contact arm An external force acts to move away from the fixing surfaces of the power supply side contact arm and the load side contact arm. In addition, when a large current such as a short-circuit current flows through the distribution path, the fixing surface of the movable contact fixed to the tip of the power supply side contact arm and the load side contact arm rises to near the melting point. The fixing force of the movable contact with respect to the load side contact arm is reduced.

  Here, in the present invention, the movable contact inserted into the notch portion of the power source side contact arm and the load side contact arm is fixed to the fixing surface of the notch portion, and the front end side and the rear end side of the movable contact are connected to each other. The pair of facing side surfaces are locked by a pair of movable contact fixed walls that rise from the front end side and the rear end side edge of the fixing surface of the notch, so that the power contact arm and Even if the force to detach from the load side contact arm is applied, and even if the fixing force of the movable contact decreases due to a large current flowing through the power distribution path, the movable contact from the tip of the power source side contact arm and load side contact arm Is reliably prevented from falling off.

  In the circuit breaker of the present invention, the pair of movable contacts are fixed to the fixed surface to be fixed to each of the power supply side contact arm and the load side contact arm, and to the position facing the fixed surface. A contact surface that is formed as a plane that is smaller than a surface and that contacts each of the first and second fixed contacts, and the pair of side surfaces that connect the fixed surface and the contact surface and face each other, And a pair of engaged surfaces inclined in directions approaching each other from the fixed surface toward the contact surface, and formed on each of the power supply side contact arm and the load side contact arm. The pair of movable contact fixed walls of the notch portions are walls inclined in the direction in which they are close to each other at the same inclination angle as the pair of engaged surfaces, and the inside of the notch portion from the opening of the side portion. When the movable contact is inserted into The pair of the engagement surface of the fixing surface vicinity and into contact with the surface contact with the pair of movable contacts fixed wall.

  According to the present invention, the movable contact is connected to each other by connecting a fixed surface having a large area and a contact surface having a small area, and is opposed to each other, and is inclined in a direction approaching each other as it goes from the fixed surface to the contact surface. The engagement surface of the member is used, and the pair of engaged surfaces of the member is used to prevent the movable contact from being detached from the power contact arm and the load contact arm. Even if the movable contact is a small movable contact in which the thickness of the side contact arm and the load side contact arm is reduced, and the movable contact has a small surface area, the movable contact can be reliably prevented from falling off.

In addition, in order to increase the fixing force to the power source side contact arm and the load side contact arm, the movable contact can be manufactured with the minimum use of expensive contact materials without increasing the area of the fixed surface of the movable contact. The manufacturing cost of the circuit breaker can be reduced.
Furthermore, the movable contact can be easily fixed to the power contact arm and the load contact arm simply by mounting from the opening position on the side of the notch provided in the power contact arm and the load contact arm. Costs can be reduced.

  According to the circuit breaker according to the present invention, the movable contact inserted into the notch portion of the power source side contact arm and the load side contact arm is fixed to the fixing surface of the notch portion, and the leading end side and the rear side of the movable contact point. A pair of side surfaces facing the end side are locked by a pair of movable contact fixed walls that rise from the leading edge and rear edge of the fixing surface of the notch. The tip of the power supply side contact arm and the load side contact arm even if the force that tries to detach from the contact arm and the load side contact arm is applied, and the fixing force of the movable contact is reduced due to a large current flowing through the power distribution path It is possible to reliably prevent the movable contact from falling off.

It is a perspective view which shows the electric current interruption part of the injection state which comprises the circuit breaker which concerns on this invention. It is a perspective view which shows the movable contact of the electric current interruption part of the current-limiting open state based on this invention. It is side sectional drawing which shows the electric current interruption part of the current limiting opening state which concerns on this invention. It is a principal part exploded perspective view which shows the structure of the movable contact which comprises the circuit breaker which concerns on this invention. It is a figure which shows the site | part which adheres the movable contact which comprises the movable contact which concerns on this invention, and the movable contact of a power supply side contact arm. It is a figure which shows the state which the movable contact contact | abuts to the stopper wall, inclining in the current limiting opening state of the electric current interruption part which concerns on this invention. It is a figure which shows the state in which a movable contact inclines in the reverse side in the current limiting opening state of the electric current interruption part which concerns on this invention. It is a figure which shows the state which the movable contact contact | abuts to a stopper wall, inclining in the reverse side in the current limiting opening state of the electric current interruption part which concerns on this invention. It is a figure which shows the structure of a circuit breaker. It is a principal part disassembled perspective view which shows the structure of the movable contact which comprises the conventional circuit breaker. It is side sectional drawing which shows the injection state of the current interruption part of the conventional circuit breaker. It is a perspective view which shows the principal part of the injection | throwing-in state of the conventional electric current interruption part. It is a sectional side view which shows the current-limiting open state of the current interruption part of the conventional circuit breaker. It is a perspective view which shows the principal part of the current limiting opening state of the conventional electric current interruption part. It is a figure which shows the state which the bridge contactor contact | abuts to the stopper wall, inclining in the current limiting opening state of the conventional electric current interruption part. It is a figure which shows the state which the bridging contactor is contacting the stopper wall, inclining in the reverse side in the current limiting opening state of the conventional electric current interruption part.

DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component as the structure shown in FIGS. 9-16, and the description is abbreviate | omitted.
The circuit breaker of this embodiment includes a current interrupting unit 15 shown in FIGS.
The current interrupting unit 15 includes a first fixed contact 6 connected to the power supply side terminal and a second fixed contact 7 connected to the load side terminal via the operating element of the overcurrent trip device 5. And a bridging type provided with fixed contacts 6a, 7a fixed to the tips of the first and second fixed contacts 6, 7, and a pair of movable contacts 18c, 18d bridging the fixed contacts 6a, 7a. A movable contact 18 and an end connected to the movable contact 18, and a movable contact arm 9 that rotates the movable contact 18 in a direction to release from the fixed contacts 6 a and 7 a by a trip operation from the toggle link mechanism 3. And the arc-extinguishing device 10 arranged in front of the opening movement path of the movable contact 18 corresponding to each of the fixed contacts 6a and 7a and the upper and lower rows arranged between the left and right side walls of the arc-extinguishing device 10. Arc extinguishing grid plate 10a and the inner wall of the cover 1b, Movable contactor 18 rotating to have a stop wall 11 abutting. One end side of the movable contact arm 9 is supported on the support shaft 9 a so as to be rotatable in the opening / closing direction of the movable contact 8 and the axis of the movable contact arm 9. Is connected to the center of the bridging portion 18e of the movable contact 18. The other end of the movable contact arm 9 may be coupled to the bridging portion 18e of the movable contact 18 so as to be rotatable about the axis of the movable contact arm 9.

As shown in FIG. 2, the movable contact 18 includes a power supply side contact arm 18 a and a load side contact arm that extend in parallel with each other from opposite edges of the rectangular plate-shaped bridging portion 18 e and form a U shape. 18b, and movable contacts 18c and 18d fixed to the tips of the power supply side contact arm 18a and the load side contact arm 18b.
As shown in FIG. 4, the movable contact 18c fixed to the power supply side contact arm 18a is a hexahedral member surrounded by six square planes. That is, as shown in FIG. 5A, the movable contact 18c has a rectangular contact surface 18c1 that contacts the first fixed contact 6a and a quadrangular adherend that is fixed to the power supply side contact arm 18a. A surface 18c2, a pair of side surfaces 18c3 forming an inverted trapezoidal plane provided between the contact surface 18c1 and the fixed surface 18c2, and a pair of side surfaces 18c4 provided to intersect the pair of side surfaces 18c3. Has been. The contact surface 18c1 that contacts the first fixed contact 6a has a smaller area than the fixed surface 18c2 that is fixed to the power supply side contact arm 18a. Further, the pair of side surfaces 18c4 intersecting with the pair of side surfaces 18c3 formed as inverted trapezoidal planes are changed from the edge portion (upper portion) of the fixed surface 18c2 having a large area to the edge portion (lower portion) of the contact surface 18c1 having a small area. The taper surfaces are inclined downward at the same angle in the direction approaching each other as they go (hereinafter, a pair of side surfaces 18c4 is referred to as a pair of engaged surfaces 18c4).

  As shown in FIG. 4, a notch portion 18a1 formed in a concave shape with a side opening is provided at the lower end on the distal end side of the power supply side contact arm 18a. The notch 18a1 extends downward from a fixing surface 18a2 formed in a plane having substantially the same shape as the fixed surface 18c2 of the movable contact 18c, and an edge on the front end side and rear end side of the fixing surface 18a2. It is comprised with a pair of movable contact fixed wall 18a3.

As shown in FIG. 5 (b), the pair of movable contact fixed walls 18a3 are formed as surfaces inclined downward at the same angle in a direction approaching each other according to the separation from the fixing surface 18a2. The inclination angle of the pair of movable contact fixed walls 18a3 is set to be substantially the same as that of the pair of engaged surfaces 18c4 of the movable contact 18c described above.
In order to fix the movable contact 18c to the tip of the power supply side contact arm 18a, the movable contact 18c is mounted in the notch 18a1 from the side opening of the power supply side contact arm 18a shown by the arrow in FIG. As a result, the fixed surface 18c2 of the movable contact 18c is fixed to the fixed surface 18a2 of the cutout portion 18a1 of the power supply side contact arm 18a in a surface contact state, and is movable to the pair of movable contact fixed walls 18a3 of the cutout portion 18a1. The upper portions of the pair of engaged surfaces 18c4 of the contact 18c come into contact with each other in a surface contact state.

  On the other hand, the movable contact 18d fixed to the load side contact arm 18b has the same shape as the movable contact 18c fixed to the power supply side contact arm 18a, and is a fixed notch formed at the lower end of the load side contact arm 18b. 18b1 also has the same shape as the fixed notch 18a1 formed at the lower end of the tip of the power supply side contact arm 18a. The operation for fixing the movable contact 18d to the tip of the load side contact arm 18b is performed in the same procedure as the operation for fixing the movable contact 18c to the power source side contact arm 18a.

Next, the effect of this embodiment is demonstrated with reference to FIGS.
In the current limiting opening process, the power source side contact arm 18a and the load side contact arm 18b of the movable contact 18 receive electromagnetic repulsive forces having different magnitudes. For this reason, as shown in FIG. 6, in the movable contact 18 connected to the movable contact arm 9, first, the load side contact arm 18b having a large electromagnetic repulsive force is placed on the stopper wall 11 from the power source side contact arm 18a. The movable contact 8 is inclined so as to be close to each other, and the load side contact arm 8 b comes into contact with the stopper wall 11. The movable contact 18 that has received the impact reaction force of the load side contact arm 8b rotates around the axis of the movable contact arm 9 as shown in FIG. 7, and then, as shown in FIG. 8, the power side contact arm 18a. Is inclined closer to the stopper wall 11 than the load side contact arm 18b, and the power source side contact arm 18a contacts the stopper wall 11. As described above, in the circuit breaker, in the current limiting opening process, the load side contact arm 18b and the power source side contact arm 18a are alternately brought into contact with the stopper wall 11 so that the movable contact 18 exhibits a swinging behavior. An impact is received from the stopper wall 11.

  As described above, when the movable contact 18 receives an impact from the stopper wall 11 while exhibiting a swinging behavior in the process of current limiting opening, the notches 18a1 and 18b1 of the power supply side contact arm 18a and the load side contact arm 18b are applied. An external force is applied to the fixed movable contacts 18c and 18d to separate from the fixing surface 12a2 of the notch 18a1 of the power supply side contact arm 18a and the fixing surface of the notch 18b1 of the load side contact arm 18b.

Further, when a large current flows through the distribution path and a current limiting opening operation is performed, the fixed surface 18c2 of the movable contact 18c fixed to the power supply side contact arm 18a and the movable contact fixed to the load side contact arm 18b. Since the fixed surface of the contact 18d rises to near the melting point, the fixing force of the movable contacts 18c and 18d to the power supply side contact arm 18a and the load side contact arm 18b is reduced.
Here, in the present embodiment, when the movable contact 18c mounted in the notch 18a1 of the power supply side contact arm 18a is fixed by bringing the fixed surface 18c2 into surface contact with the fixing surface 18a2 of the notch 18a1, the movable contact 18c is movable. The upper portions of the pair of engaged surfaces 18c4 provided with the downward contact in the direction close to each other provided on the contact 18c are provided with the downward inclination in the direction close to each other at the same inclination angle as the pair of engaged surfaces 18c4. The power supply side contact arm 18a contacts the pair of movable contact fixed walls 18a3. The pair of movable contact fixed walls 18a3 restrains the sliding of the pair of engaged surfaces 18c4 and prevents the movable contact 18c from detaching from the power source side contact arm 18a. Even if the force for detaching from the contact arm 18a is applied and a large current flows through the power distribution path and the fixing force of the movable contact 18c is reduced, the movable contact 18c is dropped from the tip of the power supply side contact arm 18a. Can be reliably prevented.

  Further, even if a force for detaching from the load side contact arm 18b is applied to the movable contact 18d due to the swing behavior, and even if the fixing force of the movable contact 18d is reduced due to a large current flowing through the power distribution path, the load side contact is reduced. Since the arm 18b has the same structure as the power supply side contact arm 18a that fixes the movable contact 18c and the movable contact 18d is fixed, the arm 18b prevents the movable contact 18d from dropping from the tip of the load side contact arm 18b. Can do.

  Further, the movable contacts 18c and 18d of the present embodiment have a pair of side surfaces (side surface 18c3 for the movable contact 18c) as an inverted trapezoidal plane, and another pair of side surfaces (covered by the movable contact 18c) that intersect the pair of side surfaces. This is a simple hexahedral contact member having a pair of tapered surfaces as the engagement surfaces 18c4), and a pair of tapered surfaces having a downward slope in a direction approaching the side surfaces of the contact members. Since the movable contacts 18c and 18d are prevented from detaching from the contact arm 18a and the load-side contact arm 18b, for example, a small movable contact 18 in which the wall thickness of the power-side contact arm 18a and the load-side contact arm 18b is reduced is used. The movable contacts 18c and 18d having a small surface area to be fixed to the tips of the power supply side contact arm 18a and the load side contact arm 18b may be movable contacts. 18c, it is possible to reliably prevent the falling off of the 18d.

Further, in order to increase the fixing force with respect to the power supply side contact arm 18a and the load side contact arm 18b, the area of the fixed surface of the movable contacts 18c, 18d is not increased, and the use of expensive contact materials is minimized and the movable contact 18c, Since 18d can be manufactured, the manufacturing cost of the circuit breaker can be reduced.
Furthermore, the movable contacts 18c and 18d are mounted from the side opening positions of the cutout portions 18a1 and 18b1 provided in the power supply side contact arm 18a and the load side contact arm 18b, and can be attached to the power supply side contact arm 18a and the load side contact arm. Since it is fixed to 18b, the assembly cost can be reduced.

  In this embodiment, the movable contacts 18c and 18d are hexahedral contact members having a pair of side surfaces that are inverted trapezoidal, and the notches 18a1 and 18a1 of the power-side contact arm 18a and the load-side contact arm 18b are used. 18b1 is provided with an inclined surface (a pair of movable contact fixed walls 18a3 in the power supply side contact arm 18a) that engages a pair of tapered surfaces (the engaged surface 18c4 in the movable contact 18c) of the movable contacts 18c and 18d. However, the gist of the present invention is not limited to this, and a pair of side surfaces facing the front end side and the rear end side of the movable contact are formed in the notches of the power source side contact arm and the load side contact arm. If it is the structure latched by the movable contact fixed wall, it may be a polyhedral movable contact of another shape and a pair of movable contact fixed walls of other shapes.

  DESCRIPTION OF SYMBOLS 1a ... Case, 1b ... Cover, 2 ... Operation handle, 3 ... Toggle link mechanism (opening / closing mechanism), 4 ... Current interruption part, 5 ... Overcurrent tripping device, 6 ... 1st stationary contact, 6a, 7a ... Fixed contact, 7 ... second fixed contact, 9 ... movable contact arm (rotating arm), 9a ... support shaft, 10 ... arc extinguishing device, 10a ... arc extinguishing grid plate, 11 ... stopper wall (stopper part) , 15 ... current interrupting part, 18 ... movable contact, 18a ... power supply side contact arm, 18a1 ... notch, 18a2 ... fixing surface, 18a3 ... movable contact fixed wall, 18b ... load side contact arm, 18b1 ... notch 18c, 18d ... movable contact, 18c1 ... contact surface, 18c2 ... fixed surface, 18c3 ... side surface, 18c4 ... engaged surface, 18d ... movable contact, 18e ... bridging part, A1, A2 ... arc

Claims (2)

A bridge provided with a first fixed contact connected to the power supply side terminal, a second fixed contact connected to the load side terminal, and a pair of movable contacts bridging the first and second fixed contacts A movable arm having a shape, and a rotating arm having an end connected to the movable contact, and rotating the movable contact toward the opening end position by a current limiting opening operation of the opening / closing mechanism when an overcurrent occurs A stopper portion that stops the rotation of the movable contact at the opening end position, and the movable contact is configured so that the power contact arm and the load contact arm are in the same direction from both ends of the bridge portion. A circuit that extends, the pair of movable contacts are respectively fixed to the tip ends of the power supply side contact arm and the load side contact arm, and the bridging portion is rotatable about the axis of the rotating arm. In the circuit breaker,
A concave notch with an open side is formed at the lower end of each of the power source side contact arm and the load side contact arm, and the notch has a fixing surface for fixing the movable contact; A pair of movable contact fixed walls that rise from the edge on the front end side and the edge on the rear end side of the fixed surface and prevent the movable contact from moving away from the fixed surface;
The movable contact is inserted into the notch from the opening of the side portion, the movable contact is fixed to the fixing surface, and a pair of side surfaces facing the front end side and the rear end side of the movable contact are connected to the pair. A circuit breaker that is locked by a movable contact fixed wall. The pair of movable contacts is formed as a fixed surface fixed to each of the power supply side contact arm and the load side contact arm, and a plane smaller than the fixed surface at a position facing the fixed surface, A contact surface that contacts each of the first and second fixed contacts, and the pair of side surfaces that connect the fixed surface and the contact surface and face each other, from the fixed surface toward the contact surface And a pair of engaged surfaces inclined in directions close to each other according to
The pair of movable contact fixed walls of the notch formed in each of the power supply side contact arm and the load side contact arm is inclined in the direction in which they are close to each other at the same inclination angle as the pair of engaged surfaces. A wall with
When the movable contact is inserted into the notch from the opening of the side portion, the pair of engaged surfaces in the vicinity of the fixed surface comes into contact with the pair of movable contact fixed walls in a surface contact state. The circuit breaker according to claim 1.

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