Tripping device, circuit breaker, and distribution board

Abstract

The purpose of the present disclosure is to provide: a tripping device in which high tripping force is generated through a movable iron piece moving toward a fixed iron piece; a circuit breaker; and a distribution board. A tripping device (1) comprises a fixed iron piece (11), a movable iron piece (12), and a push-in part (14). The movable iron piece (12) is configured to move toward the fixed iron piece (11) when an abnormality occurs. The push-in part (14) pushes a latch part (3) from a latched position into a non-latched position in conjunction with the movable iron piece (12) moving toward the fixed iron piece (11). The movable iron piece (12) has a second surface (X2) that faces a first surface (X1) of the fixed iron piece (11). The movable iron piece (12) is configured to keep the second surface (X2) parallel to the first surface (X1) while the movable iron piece (12) is moving toward the fixed iron piece (11).

Description

Tripping devices, circuit breakers, and distribution boards

[0001] The present disclosure generally relates to a trip device, a circuit breaker, and a distribution board, and more particularly to a trip device, a circuit breaker, and a distribution board that open contacts when a fault occurs.

[0002] Patent Document 1 describes a circuit breaker in which an overcurrent tripping unit accommodating chamber, a switching mechanism unit accommodating chamber, an arc barrier accommodating chamber, and a contact unit accommodating chamber are formed within a housing. The overcurrent tripping unit accommodating chamber accommodates the overcurrent tripping unit and is located between the load side terminal unit and the switching mechanism unit accommodating chamber. The switching mechanism unit accommodating chamber is located between the overcurrent tripping unit accommodating chamber and the power supply side terminal unit. The arc barrier accommodating chamber is located between the power supply side terminal unit and the load side terminal unit, and is located below the overcurrent tripping unit accommodating chamber and the switching mechanism unit accommodating chamber. The contact unit accommodating chamber is located at the end of the arc barrier accommodating chamber on the power supply side terminal unit side.

[0003] Incidentally, a tripping device such as the overcurrent tripping unit of the circuit breaker described in Patent Document 1 may be configured to include a fixed iron piece and a moving iron piece instead of an electromagnet, and to open the contacts by moving the moving iron piece toward the fixed iron piece when an abnormality occurs. In this case, the tripping device is required to have a high tripping force generated by the movement of the moving iron piece toward the fixed iron piece.

[0004] JP 2013-77423 A

[0005] An object of the present disclosure is to provide a tripping device, a circuit breaker, and a distribution board that generate a high tripping force when a movable iron piece moves toward a fixed iron piece.

[0006] A tripping device according to one aspect of the present disclosure is a tripping device that, when an abnormality occurs in power supplied from an external power source to a load via a contact portion, moves a latch portion from a latched position to an unlatched position, thereby opening the contact portion. The tripping device includes a fixed iron piece, a movable iron piece, and a pushing portion. The movable iron piece is configured to move toward the fixed iron piece when the abnormality occurs. The pushing portion is interlocked with the movable iron piece moving toward the fixed iron piece, and pushes the latch portion from the latched position to the unlatched position. The movable iron piece has a second surface that faces the first surface of the fixed iron piece. The movable iron piece is configured so that the second surface remains parallel to the first surface while moving toward the fixed iron piece.

[0007] A circuit breaker according to one aspect of the present disclosure includes the tripping device, a first terminal unit, a second terminal unit, the contact unit, and the latch unit. The first terminal unit is electrically connected to the external power supply. The second terminal unit is electrically connected to the load. The contact unit is inserted into an electrical path between the first terminal unit and the second terminal unit. The latch unit opens the contact unit by being pushed from the latched position to the non-latching position by the push-in unit.

[0008] A distribution board according to one aspect of the present disclosure includes the circuit breaker and a cabinet that houses the circuit breaker.

[0009] FIG. 1 is a plan view of the circuit breaker according to the present embodiment with the first block removed, showing the contacts closed. FIG. 2 is a plan view of the circuit breaker according to the present embodiment with the first block removed, showing the contacts open. FIG. 3 is a plan view of a circuit breaker according to a comparative example with a portion of the first block omitted, showing the contacts closed. FIG. 4 is an external view of a distribution board including the circuit breaker according to the present embodiment. FIG. 5 is a perspective view of the circuit breaker according to the present embodiment. FIG. 6 is an external perspective view of a tripping device in the circuit breaker according to the present embodiment. FIG. 7A is a plan view of essential parts including the tripping device in the circuit breaker according to the present embodiment in FIG. 1. FIG. 7B is a plan view of essential parts including the tripping device in the circuit breaker according to the present embodiment in FIG. 2. FIG. 8 is an explanatory diagram illustrating changes in tripping force depending on the amount of movement of the pushing portion of the tripping device in the circuit breaker according to the present embodiment. FIG. 9 is a plan view of essential parts of a circuit breaker according to a first modified example with the first block removed, showing the contacts closed.

[0010] The embodiments and modifications described below are merely examples of the present disclosure. The present disclosure is not limited to the embodiments and modifications, and various modifications other than these embodiments and modifications are possible depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure. The drawings described in the following embodiments and modifications are schematic drawings, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0011] (Present Embodiment) (1) Overview Hereinafter, an overview of a tripping device 1 according to this embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0012] The tripping device 1 of this embodiment is installed inside the circuit breaker 10, and when an abnormality occurs in the power supplied from an external power source to a load via the contact part 2, the latch part 3 is moved from the latch position to the non-latching position to open the contact part 2.

[0013] The "latched position" in this disclosure is a position where the latch portion 3 closes the contact portion 2, as shown in Fig. 1. On the other hand, the "non-latched position" in this disclosure is a position where the latch portion 3 opens the contact portion 2, as shown in Fig. 2.

[0014] 1 and 2, the tripping device 1 includes a fixed iron piece 11, a movable iron piece 12, and a pushing portion 14. The movable iron piece 12 is configured to move toward the fixed iron piece 11 when an abnormality occurs in the power supplied from an external power source to a load via the contact portion 2. The pushing portion 14 moves in conjunction with the movable iron piece 12 moving toward the fixed iron piece 11, and pushes the latch portion 3 from the latched position to the unlatched position.

[0015] The movable iron piece 12 has a second surface X2 that faces the first surface X1 of the fixed iron piece 11. The movable iron piece 12 is configured so that the second surface X2 remains parallel to the first surface X1 while moving toward the fixed iron piece 11. In this disclosure, "parallel" is not limited to being strictly parallel, and a slight error (for example, ±2 degrees) is allowed.

[0016] As shown in FIG. 3 , in the tripping device A1 of the circuit breaker A10 according to the comparative example, the second surface AX2 of the armature A12 is not parallel to the first surface AX1 of the fixed armature A11. As the armature A12 moves toward the fixed armature A11, the second surface AX2 rotates around the center point P1 to approach the first surface AX1. That is, as the armature A12 moves toward the fixed armature A11, the clearance between the fixed armature A11 and the armature A12 is not uniform. As a result, the force with which the fixed armature A11 attracts the armature A12 (hereinafter also referred to as "attraction force") varies in strength depending on the location of the armature A12 where the attraction force acts. More specifically, the attraction force acting on a portion of the armature A12 far from the center point P1 is weaker than the attraction force acting on a portion of the armature A12 closer to the center point P1. As a result, the tripping device A1 of the circuit breaker A10 according to the comparative example may have a problem in that it is unable to exert a sufficient attractive force when the movable iron piece A12 begins to move toward the fixed iron piece A11.

[0017] However, in the tripping device 1 of the circuit breaker 10 of this embodiment, the armature 12 is configured so that the second surface X2 remains parallel to the first surface X1 while moving toward the fixed armature 11. In other words, the clearance between the fixed armature 11 and the armature 12 is uniform while the armature 12 moves toward the fixed armature 11. Therefore, the magnitude of the attractive force with which the fixed armature 11 attracts the armature 12 is substantially uniform, regardless of the location on the armature 12 where the attractive force acts. This provides the advantage that the attractive force can be sufficiently exerted even when the armature 12 begins to move toward the fixed armature 11 (hereinafter also referred to as the "initial state"). As a result, in the initial state, the moving speed of the armature 12 increases, and the pushing portion 14, which moves in conjunction with the armature 12, strongly pushes the latch portion 3. That is, the tripping device 1 of this embodiment has the advantage that, compared to the tripping device A1 of the circuit breaker A10 according to the comparative example, the tripping force generated by the movement of the movable iron piece 12 toward the fixed iron piece 11 is higher. The "tripping force" referred to in this disclosure is the force with which the latch part 3 separates the contact part 2, i.e., the force with which the contact part 2 opens.

[0018] (2) Detailed Configuration Hereinafter, detailed configurations of the trip device 1, the circuit breaker 10, and the distribution board 100 according to this embodiment will be described with reference to FIGS. 1 to 8. FIG.

[0019] (2-1) Distribution Board As shown in Fig. 4, the distribution board 100 according to this embodiment includes a main breaker 91, a plurality of (12 in the illustrated example) branch breakers 92, a cabinet 93, and an outer cover (not shown). In this embodiment, each of the plurality of branch breakers 92 is a circuit breaker 10. The distribution board 100 is installed, for example, in a residence (or a non-residence).

[0020] The cabinet 93 is made of, for example, synthetic resin. As shown in Fig. 4 , the cabinet 93 is formed in a box shape with an open front, and is attached to a wall of a house or the like for use. The cabinet 93 houses a main breaker 91 and a plurality of branch breakers 92 (circuit breakers 10). More specifically, the cabinet 93 has a space for housing the main breaker 91 and the plurality of branch breakers 92 (circuit breakers 10). The outer cover is attached to the cabinet 93 in a state where it can move between a position that closes the front of the cabinet 93 and a position that opens it.

[0021] The main breaker 91 has a primary terminal and a secondary terminal. An external power source is electrically connected to the primary terminal of the main breaker 91. In the present disclosure, the "external power source" refers to a power source that supplies power to a load, such as a system power source (commercial power source). The distribution board 100 according to this embodiment assumes a single-phase three-wire system as the power distribution method, and therefore a single-phase three-wire service line of the system power source (commercial power source) is electrically connected to the primary terminal of the main breaker 91. That is, in this embodiment, the main breaker 91 has two voltage poles and one neutral pole. Each circuit breaker 10 is electrically connected to the secondary terminal of the main breaker 91.

[0022] The circuit breakers 10 are arranged in a row in the left-right direction, above and below the conductive bar of the neutral pole, with multiple units (six units in the illustrated example) on each side. Each circuit breaker 10 has a primary terminal and a secondary terminal.

[0023] The primary terminal of the circuit breaker 10 is electrically connected to the secondary terminal of the master breaker 91. In other words, an external power source is electrically connected to the primary terminal of the circuit breaker 10 via the master breaker 91. One or more loads are electrically connected to the secondary terminal of the circuit breaker 10. In this disclosure, the term "load" includes not only electrical equipment such as lighting fixtures and hot water supply equipment, but also wiring devices such as electrical outlets and wall switches. Details of the circuit breaker 10 will be explained in the section "(2-2) Circuit Breaker."

[0024] (2-2) Circuit Breaker (2-2-1) Overall Configuration As shown in Figures 1 and 2, the circuit breaker 10 comprises a tripping device 1, a contact section 2, a latch section 3 (such as an operating handle 6), a bimetal plate 4, a body 5, a pair of terminal sections 7, a fixed contact plate 81, a braided wire 82, a metal plate 83, and an arc extinguishing device 84.

[0025] The circuit breaker 10 has a function (overcurrent detection function) of detecting an overcurrent, such as a short-circuit current or an overload current, and interrupting the flow of electricity from an external power source to a load (the flow of electricity through the main circuit) by switching the contact unit 2 from closed to open. The circuit breaker 10 is also configured to be able to switch the contact unit 2 from closed to open and from open to closed in response to manual operation of the operating handle 6. For example, after the contact unit 2 is opened due to detection of an abnormal current, a user can close the contact unit 2 by operating the operating handle 6 if safety is confirmed. The main circuit of this embodiment is an electrical path for supplying power from an external power source to a load, and is an electrical path between a first terminal 7A and a second terminal 7B (described later) of a pair of terminals 7. The main circuit is composed of a fixed contact plate 81, a latch unit 3, a braided wire 82, a bimetal plate 4, a metal plate 83, and the like.

[0026] (2-2-2) Circuit Breaker Body As shown in FIG. 5 , the circuit breaker body 5 has a generally flat, approximately rectangular box shape. Hereinafter, the direction along the thickness direction of the circuit breaker body 5 will be referred to as the "left-right direction" of the circuit breaker 10. Hereinafter, the direction in which the pair of terminal portions 7 are lined up, as shown in FIG. 1 , will be referred to as the "up-down direction," and the downward direction when viewed from the front of the circuit breaker 10 will be referred to as the "downward direction." The right side when viewed from the front of the circuit breaker 10 will be referred to as the "rightward direction," and the left side when viewed from the front of the circuit breaker 10 will be referred to as the "leftward direction." Furthermore, the direction perpendicular to both the up-down direction and the left-right direction will be referred to as the "front-rearward direction," and the side of the circuit breaker body 5 on which the operating handle 6 is provided will be referred to as the "frontward direction." However, these directions are not intended to limit the direction in which the circuit breaker 10 is used.

[0027] 5, the housing 5 has a first block 5A (right block) and a second block 5B (left block). The first block 5A and the second block 5B are made of an electrically insulating synthetic resin material.

[0028] The housing 5 accommodates the tripping device 1, the contact portion 2, the latch portion 3, the bimetal plate 4, the operating handle 6, the pair of terminal portions 7, the fixed contact plate 81, the braided wire 82, the metal plate 83, and the arc extinguishing device 84. As shown in Figures 1 to 2 and 5, the housing 5 supports a part of the operating handle 6 (the lever 61) so that it is exposed to the outside from the front wall 55. As shown in Figure 5, the front wall 55 protrudes forward so that the central portion in the up-down direction is convex, and the lever 61 is exposed to the outside from a window hole 56 in the protruding central portion.

[0029] The first block 5A and the second block 5B are formed in a generally rectangular box shape with open faces facing each other. The housing 5 is formed by joining the first block 5A and the second block 5B together by butting them together.

[0030] (2-2-3) Terminals As shown in FIGS. 1 and 2 , one of the pair of terminals 7, the first terminal 7A, is housed in the upper end of the housing 5, and the other, the second terminal 7B, is housed in the lower end of the housing 5. In the following description, it is assumed that an electric wire on the external power source (e.g., a commercial AC power source) side is electrically connected to the first terminal 7A, and an electric wire on the load side is electrically connected to the second terminal 7B. That is, it is assumed that the first terminal 7A is the above-mentioned primary side terminal to which the secondary side terminal of the main breaker 91 is electrically connected, and the second terminal 7B is the above-mentioned secondary side terminal to which the load is electrically connected. Note that the first terminal 7A may be electrically connected to the electric wire on the load side, and the second terminal 7B may be electrically connected to the electric wire on the external power source side.

[0031] The first terminal 7A and the second terminal 7B are, for example, so-called pillar terminals (screw-type terminals) that can be connected by screws. As shown in Fig. 1 , the first terminal 7A has a terminal board 71, a terminal fitting 72, and a terminal screw 73. The second terminal 7B has the terminal fitting 72 and the terminal screw 73.

[0032] The terminal plate 71 is made of a conductive metal plate and is formed into a generally L-shaped plate shape. The terminal plate 71 is fixed inside the housing 5.

[0033] The terminal fittings 72 are formed into a rectangular tube shape using a conductive metal plate. The terminal fittings 72 are axially aligned in the vertical direction, with both ends open in the vertical direction. The terminal fittings 72 of the first terminal portion 7A are movable within a predetermined range in the front-to-rear direction within the housing 5 with a portion of the terminal plate 71 (projection 711) inserted therein. Meanwhile, the terminal fittings 72 of the second terminal portion 7B are movable within a predetermined range in the front-to-rear direction within the housing 5 with a portion of the fixed contact plate 81 (projection 811) inserted therein. The terminal fittings 72 also have screw holes into which terminal screws 73 are threaded. The housing 5 has insertion openings 51 (two in total) for inserting electric wires at a portion that overlaps the gap between the projection 711 (or projection 811) and the bottom wall of the terminal fittings 72 when viewed from the vertical direction.

[0034] The terminal screws 73 are housed in the housing 5 with their screw tips threaded into the screw holes of the terminal fittings 72. The housing 5 has holes 52 (two in total) in the front wall 55 at portions that overlap the heads of the terminal screws 73 when viewed from the front to back, through which the heads of the terminal screws 73 are exposed without falling out.

[0035] In the first terminal 7A, with the wire on the external power supply side inserted from the socket 51 into the gap between the protrusion 711 and the bottom wall of the terminal fitting 72, the tip of a tool such as a screwdriver is inserted through the hole 52 and the terminal screw 73 is tightened, moving the terminal fitting 72 forward and reducing the distance between the protrusion 711 and the bottom wall of the terminal fitting 72. As a result, the wire on the external power supply side that was inserted into the gap can be connected to the terminal 7.

[0036] Similarly, in the second terminal 7B, with the load-side electric wire inserted from the insertion port 51 into the gap between the protrusion 811 and the bottom wall of the terminal fitting 72, the tip of a tool such as a screwdriver is inserted through the hole 52 and the terminal screw 73 is tightened, moving the terminal fitting 72 forward and reducing the distance between the protrusion 811 and the bottom wall of the terminal fitting 72. As a result, the load-side electric wire inserted in the gap can be connected to the terminal 7.

[0037] (2-2-4) Contact Unit The contact unit 2 is configured to open when an abnormality occurs in the power supplied from the external power supply to the load via the contact unit 2. More specifically, the contact unit 2 is configured to open in response to the occurrence of an abnormal current (here, as examples, a leakage current, a short-circuit current, or an overload current) in the main circuit, thereby switching the main circuit from a conducting state to a cut-off state. The contact unit 2 is inserted in the electric path between the first terminal unit 7A and the second terminal unit 7B.

[0038] 1 and 2, the contact unit 2 has a fixed contact 2A and a movable contact 2B that comes into contact with or separates from the fixed contact 2A. Fig. 1 shows the contact unit 2 in a closed state, and Fig. 2 shows the contact unit 2 in an open state.

[0039] The fixed contact 2A is provided on a fixed contact plate 81. More specifically, the fixed contact 2A is a recess provided on the fixed contact plate 81. The fixed contact plate 81 is made of a low-resistance material such as iron or copper. The fixed contact plate 81 constitutes a part of the main circuit.

[0040] The movable contact 2B is located at one end of an arm 31 (movable contactor) of the latch portion 3, which is formed by punching and bending a metal plate. The movable contact 2B is integrated as a part of the arm 31. However, the movable contact 2B may be a separate member from the arm 31 and fixed to one end of the arm 31. The arm 31 forms part of the main circuit.

[0041] The arm 31 is rotatable about a shaft 32 provided at the other end thereof between a position where the movable contact 2B contacts the fixed contact 2A and a position where the movable contact 2B is separated from the fixed contact 2A. One end of a braided wire 82 is fixed to the middle portion of the arm 31. The braided wire 82 forms part of the main circuit.

[0042] The other end of the braided wire 82 is fixed to the middle portion of the bimetal plate 4. An end (rear end) of the bimetal plate 4 is fixed to one end of the metal plate 83, and the other end of the metal plate 83 is fixed to the terminal plate 71 of the first terminal portion 7A. The bimetal plate 4 and the metal plate 83 form part of the main circuit.

[0043] When the contact portion 2 is closed, the power supplied (output) to the first terminal portion 7A from the external power source passes through the main circuit and is supplied (input) to the load from the second terminal portion 7B. More specifically, the power output from the external power source to the first terminal portion 7A passes through the main circuit in the listed order of the metal plate 83, the bimetal plate 4, the braided wire 82, the latch portion 3, and the fixed contact plate 81, and is input to the load from the second terminal portion 7B.

[0044] (2-2-5) Latch Unit The latch unit 3 is configured to open or close the contact unit 2 in response to an opening operation (OFF operation) or a closing operation (ON operation). More specifically, the latch unit 3 is configured to maintain one of two states: a state in which the movable contact 2B is in contact with the fixed contact 2A, and a state in which the movable contact 2B is separated from the fixed contact 2A, in response to an opening operation or a closing operation. When the latch unit 3 is in the latched position (see FIG. 1), the latch unit 3 closes the contact unit 2, i.e., maintains the state in which the movable contact 2B is in contact with the fixed contact 2A. On the other hand, when the latch unit 3 is in the non-latching position (see FIG. 2), the latch unit 3 opens the contact unit 2, i.e., maintains the state in which the movable contact 2B is separated from the fixed contact 2A.

[0045] The latch unit 3 has an operating handle 6, a plurality of latch members 30, and an arm 31. The operating handle 6 is rotatably supported on the body 5 with a lever (operating knob) 61 protruding from a window hole 56 (see FIG. 5 ) provided in a front wall 55 of the body 5 to the outside of the body 5. Each latch member 30 connects the operating handle 6 to the arm 31, and moves the arm 31 in conjunction with the rotation of the operating handle 6. The operating handle 6 is rotatable between an ON position, which closes the contact unit 2, and an OFF position, which opens the contact unit 2.

[0046] In Fig. 1, the contact unit 2 is in a closed state, and the lever 61 of the operating handle 6 is tilted upward. On the other hand, in Fig. 2, the contact unit 2 is in an open state, and the lever 61 of the operating handle 6 is tilted downward.

[0047] (2-2-6) Tripping Device The tripping device 1 is configured to drive the latch unit 3 described above to forcibly open the contact unit 2 (i.e., to separate the movable contact 2B from the fixed contact 2A) when an abnormality occurs in the power supplied from the external power source to the load via the contact unit 2. More specifically, the tripping device 1 is configured to drive the latch unit 3 described above to forcibly open the contact unit 2 when an abnormal current is detected in the main circuit.

[0048] As shown in Figures 6, 7A, and 7B, the tripping device 1 comprises a fixed iron piece 11, a movable iron piece 12, a holder 13, a pushing portion 14, and multiple links 15 (two in Figure 1).

[0049] The fixed iron piece 11 is made of a magnetic material and is a plate member having a substantially U-shape as shown in FIG. 6 . More specifically, the fixed iron piece 11 has a first portion 111, a second portion 112, and a third portion 113. The first portion 111 is a rectangular plate member whose thickness direction intersects (here, perpendicular to) the left-right direction. In this embodiment, the first portion 111 is accommodated in the housing 5 so that its upper end is located forward of its lower end, as shown in FIG. 7A . In other words, in this embodiment, the thickness direction of the first portion 111 does not align with the front-rear direction but slightly intersects with it. As shown in FIG. 6 , the second portion 112 is a substantially rectangular plate member that protrudes forward from the right end of the first portion 111 along the thickness direction of the first portion 111. Similarly, the third portion 113 is a substantially rectangular plate member that protrudes forward from the left end of the first portion 111 along the thickness direction of the first portion 111. The second portion 112 and the third portion 113 face each other in the left-right direction. Each of the second portion 112 and the third portion 113 has a first surface X1, which is the surface opposite to the surface connected to the first portion 111. The first surface X1 here refers to the front end surface of each of the second portion 112 and the third portion 113. Each of the second portion 112 and the third portion 113 has a locking portion 114 that locks onto a rib (not shown) provided on the inner surface of the housing 5. Note that FIG. 6 only illustrates the first surface X1 of the second portion 112, and does not illustrate the first surface X1 of the third portion 113.

[0050] 6, the fixed iron piece 11 is accommodated in the housing 5 so that the fixed contact plate 81 is inserted therein. More specifically, the fixed iron piece 11 is accommodated in the housing 5 so that the fixed contact plate 81 is inserted between the second portion 112 and the third portion 113 in the left-right direction.

[0051] The movable iron piece 12 is configured to move toward the fixed iron piece 11 when an abnormality occurs in the power supplied from the external power source to the load via the contact portion 2. The movable iron piece 12 is a rectangular plate member made of a magnetic material. The movable iron piece 12 is housed in the housing 5 so as to face the first portion 111 of the fixed iron piece 11. That is, the thickness direction of the movable iron piece 12 is aligned with the thickness direction of the first portion 111 of the fixed iron piece 11. Therefore, as shown in FIGS. 7A and 7B , the movable iron piece 12 has a second surface X2 that faces the first surface X1 of each of the second portion 112 and the third portion 113 of the fixed iron piece 11. The second surface X2 here refers to the rear surface of the movable iron piece 12.

[0052] In this embodiment, the first surface X1 and the second surface X2 are flat surfaces. More specifically, the first surface X1 and the second surface X2 are flat surfaces that face each other.

[0053] The movable iron piece 12 is housed in the housing 5 so that the fixed contact plate 81 (see FIG. 6) is inserted between the movable iron piece 12 and the first portion 111 of the fixed iron piece 11 in the thickness direction. The thickness direction of the movable iron piece 12 does not follow the front-rear direction but slightly crosses it.

[0054] In this embodiment, the movable iron 12 is configured so that when an abnormality occurs in the power supplied from the external power source to the load via the contact portion 2, the fixed iron 11 and the movable iron 12 are magnetized, generating an attractive force (magnetic force) that attracts the fixed iron 11 to the movable iron 12, causing the fixed iron 11 to move toward the fixed iron 11. This configuration has the advantage of eliminating the need to provide a configuration for detecting an abnormality in the power supplied from the external power source to the load, or a configuration for causing the fixed iron 11 to attract the movable iron 12 by a method other than magnetic force, and thus simplifying the structure of the tripping device 1.

[0055] More specifically, when an abnormality occurs in the power supplied from the external power source to the load via the contact portion 2 and an abnormal current flows through the fixed contact plate 81, the fixed iron piece 11 and the movable iron piece 12, which are housed around the fixed contact plate 81, are magnetized. As a result, the movable iron piece 12 moves toward the fixed iron piece 11. The movable iron piece 12 is configured by the holder 13, the push-in portion 14, and the multiple links 15 to keep the second surface X2 parallel to the first surface X1 while moving toward the fixed iron piece 11. In other words, the movable iron piece 12 is configured by the holder 13, the push-in portion 14, and the multiple links 15 to move toward the fixed iron piece 11 while keeping the second surface X2 parallel to the first surface X1. When the abnormal current stops flowing through the fixed contact plate 81, the movable iron piece 12 returns to its original position by a return spring portion 132, which will be described later.

[0056] The holder 13 is a member to which the movable iron piece 12 is attached. The holder 13 moves in conjunction with the movable iron piece 12 as it moves toward the fixed iron piece 11. That is, the holder 13 moves integrally with the movable iron piece 12 as it moves toward the fixed iron piece 11. The holder 13 is substantially plate-shaped. The above configuration has the advantage that the movable iron piece 12 can move more easily.

[0057] The holder 13 of this embodiment has a base 130, a connection portion 131, and a return spring portion 132. The base 130 of this embodiment is a substantially rectangular plate member. The movable iron 12 is held on the rear surface of the base 130. The connection portion 131 is provided in the center of the front surface of the base 130. The connection portion 131 is a portion to which a first link 15A (described below) out of the multiple links 15 is connected. The return spring portion 132 is formed, for example, by a coil spring, and is provided above the connection portion 131 on the front surface of the base 130. When the movable iron 12 moves toward the fixed iron 11, the return spring portion 132 bends, generating an elastic force that moves the movable iron 12 in a direction away from the fixed iron 11.

[0058] The pushing portion 14 pushes the latch portion 3 from the latched position to the non-latching position in conjunction with the movable iron piece 12 moving toward the fixed iron piece 11. More specifically, the pushing portion 14 pushes the end portion 33 (see FIG. 7A ) of the latch portion 3 upward, thereby pushing the latch portion 3 from the latched position to the non-latching position. The pushing portion 14 of this embodiment is formed integrally with the holder 13, and moves integrally with the holder 13 when the movable iron piece 12 moves toward the fixed iron piece 11.

[0059] The pushing portion 14 is made of a material lighter than the movable iron piece 12. In this embodiment, the pushing portion 14 is integrally formed with the holder 13, and therefore the holder 13 and the pushing portion 14 are made of a material lighter than the movable iron piece 12. In this disclosure, the "material lighter than the movable iron piece 12" refers to a material containing reinforcing fibers, such as polyamide (PA), polyamideimide (PAI), polyimide (PI), PEEK (PEEK), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene (PE), ABS, polystyrene (PS), polypropylene (PP), acrylic (PMNA), polyacetal (POM), liquid crystal polymer (LCP), and melamine (MF). This configuration increases the moving speed of the movable iron piece 12 moving toward the fixed iron piece 11, enabling the latch portion 3 to be more strongly pushed from the latched position to the unlatched position. This has the advantage of enabling the tripping device 1 to exert a stronger force to separate the movable contact 2B from the fixed contact 2A. In other words, there is an advantage that the pulling force generated by the moving iron piece 12 moving toward the fixed iron piece 11 can be made higher.

[0060] As shown in FIGS. 1 , 7A, and 7B , the push-in portion 14 of this embodiment has a base portion 140, a connection portion 141, and a contact portion 142. The base portion 140 is generally rectangular plate-shaped. A first end (lower front end) of the base portion 140 is connected to an end (upper end) of the base portion 130 of the holder 13. A connection portion 141 is provided at a second end (upper rear end) of the base portion 140. The connection portion 141 is a portion to which a second link 15B (described below) of the multiple links 15 is connected. A contact portion 142 is provided on the side of the connection portion 141 opposite the base portion 140. The contact portion 142 is a portion that comes into contact with the end 33 of the latch portion 3 when the push-in portion 14 pushes in the latch portion 3. The contact portion 142 of this embodiment is triangular when viewed from the left-right direction.

[0061] Each of the multiple links 15 movably holds the movable iron piece 12. More specifically, each of the multiple links 15 holds the movable iron piece 12 so that it can move in parallel via the holder 13 and the pushing portion 14. Each of the multiple links 15 has a first end 151 (front end) that holds the movable iron piece 12 and a second end 152 (rear end) opposite the first end 151.

[0062] 1 , 2 , and 6 , the multiple links 15 include a first link 15A and a second link 15B. In the first link 15A, a first end 151 holds the movable iron 12 by clamping the connecting portion 131 of the holder 13, and a second end 152 is engaged in a recess provided on the inner surface of the body 5. On the other hand, in the second link 15B, a first end 151 holds the movable iron 12 by clamping the pushing portion 14 of the holder 13, and a second end 152 is engaged in a recess provided on the inner surface of the body 5. As a result, each of the multiple links 15 (the first link 15A and the second link 15B) performs a circular motion around the second end 152 while the movable iron 12 moves toward the fixed iron 11.

[0063] The radius of the circular motion of each of the multiple links 15 (first link 15A and second link 15B) is the same. That is, each of the multiple links 15 is configured to perform circular motion of the same radius in conjunction with the movable iron 12 while the movable iron 12 is moving toward the fixed iron 11. In other words, each of the multiple links 15 has the same dimension between the first end 151 and the second end 152. In this disclosure, "same" does not necessarily mean perfect agreement, and a slight error (e.g., ±5%) is acceptable. This configuration has the advantage of making it easier to configure the second surface X2 to remain parallel to the first surface X1 while the movable iron 12 is moving toward the fixed iron 11.

[0064] Each of the plurality of links 15 (first link 15A and second link 15B) has the same shape. This configuration has the advantage that the plurality of links 15 can use common components.

[0065] (2-2-7) Bimetal Plate The bimetal plate 4 may be a directly heated type that bends by self-heating, or an indirectly heated type that bends by heating with a heater. One end of the bimetal plate 4 is configured to cooperate with a part of the latch member 30 when the bimetal plate 4 bends. One end of the metal plate 83 is fixed to the other end of the bimetal plate 4. The other end of the metal plate 83 is fixed to the terminal plate 71 of the first terminal portion 7A.

[0066] When an overcurrent flows due to an overload, for example, the temperature of the bimetal plate 4 rises, and one end of the bimetal plate 4 deforms, bending in an upward direction. When one end of the bimetal plate 4 deforms, the bimetal plate 4 comes into contact with the contact portion 34 of the latch member 30 (see FIGS. 1 and 2 ). The pressing force of the bimetal plate 4 is transmitted to the arm 31 via the latch member 30, driving the arm 31 to separate the movable contact 2B from the fixed contact 2A. In other words, the contact portion 2 is opened. When the overcurrent due to the overload stops, the temperature of the bimetal plate 4 drops and the bimetal plate 4 returns to its original shape.

[0067] (2-2-8) Arc Extinguishing Device The arc extinguishing device 84 is configured to quickly extinguish an arc that occurs when the contact portion 2 is opened. As shown in FIGS. 1 and 2 , the arc extinguishing device 84 has an arc running plate 841 and an arc extinguishing grid 842.

[0068] The arc travel plate 841 is formed by bending a strip-shaped metal plate, and one end thereof is connected to one end (rear end) of the bimetal plate 4. The arc travel plate 841 extends along the bottom wall 57 of the housing 5. The arc extinguishing grid 842 has a plurality of arc extinguishing plates and a support portion. The plurality of arc extinguishing plates are formed from a conductive material and are arranged in parallel at intervals in the front-to-rear direction. The support portion is formed from an electrically insulating material and supports the plurality of arc extinguishing plates.

[0069] The arc extinguishing device 84 extends and divides the arc that is generated when the movable contact 2B is separated from the fixed contact 2A, thereby extinguishing the arc.

[0070] (3) Advantages In this embodiment, as shown in FIGS. 7A and 7B, the movable iron piece 12 is configured so that the second surface X2 remains parallel to the first surface X1 while moving toward the fixed iron piece 11.

[0071] According to the above configuration, the clearance between the fixed iron piece 11 and the movable iron piece 12 is uniform while the movable iron piece 12 is moving toward the fixed iron piece 11. Therefore, the magnitude of the attractive force (magnetic force) by which the fixed iron piece 11 attracts the movable iron piece 12 due to the magnetization of the fixed iron piece 11 and the movable iron piece 12 is substantially constant, regardless of the location on the movable iron piece 12 where the attractive force acts. This provides the advantage that the attractive force can be sufficiently exerted even when the movable iron piece 12 begins to move toward the fixed iron piece 11 (hereinafter also referred to as the "initial state"). As a result, in the initial state, the moving speed of the movable iron piece 12 is increased, and the pushing portion 14, which moves in conjunction with the movable iron piece 12, strongly pushes the latch portion 3. In other words, the tripping device 1 of this embodiment has the advantage of generating a higher tripping force when the movable iron piece 12 moves toward the fixed iron piece 11, compared to the tripping device A1 of the circuit breaker A10 according to the comparative example (see FIG. 3 ).

[0072] Furthermore, with the above configuration, the attractive force F1 (see FIG. 7A) generated in the movable iron piece 12 is along the thickness direction of the movable iron piece 12. Note that in FIG. 7A, the magnitude of the attractive force does not depend on the position of the movable iron piece 12 on which it acts, so for simplicity, one attractive force F1 is shown acting at the center of the movable iron piece 12.

[0073] Next, in the case shown in FIG. 7A , we consider the force F2 (i.e., the pull-out force F2 that pulls out the contact part 2) that the push-in part 14 exerts on the latch part 3 from the latched position to the unlatched position, which is generated by a single attractive force F1 acting along the thickness direction of the movable iron piece 12. Hereinafter, when the movable iron piece 12 is moving toward the fixed iron piece 11 as shown in FIG. 7A , the angle of the first link 15A relative to the thickness direction of the movable iron piece 12 is defined as θ1. The angle θ1 of the first link 15A is maximum when the movable iron piece 12 begins to move toward the fixed iron piece 11 (see FIG. 7A ), gradually decreases as the movable iron piece 12 moves toward the fixed iron piece 11, and is minimum when the movable iron piece 12 contacts the fixed iron piece 11 (see FIG. 7B ). In this embodiment, the angle θ1 of the first link 15A is 0° when the movable iron piece 12 contacts the fixed iron piece 11. The "angle θ1 of the first link 15A" here indicates the position of the movable iron piece 12 while the movable iron piece 12 is moving toward the fixed iron piece 11.

[0074] 7A , the attractive force F1 is decomposed into a first attractive force F11, which is a tangential component of the circular motion of the first link 15A, and a second attractive force F12, which is a radial component of the circular motion. Here, the pull-out force F2 is generated when the component of the first attractive force F11 acting along the surface of the armature 12 moves the armature 12 in that surface direction, and the holder 13 and the pushing portion 14, which are linked to the armature 12, push the latch portion 3 from the latched position to the unlatched position. Therefore, the pull-out force F2 is the component of the first attractive force F11 acting along the surface of the armature 12, and is calculated by the following (Equation 1).

[0075]

[0076] In the comparative tripping device A1 shown in FIG. 3 , the tripping force F2 increases exponentially as the position of the moving iron 12 moving toward the fixed iron 11 approaches the fixed iron 11. On the other hand, in the tripping device 1 of this embodiment, the tripping force F2 is affected by "cos θ1 × sin θ1" as shown in Equation 1. Therefore, compared to the tripping device A1 of the comparative example, the tripping force F2 fluctuates less with respect to the position (angle θ1) of the moving iron 12 moving toward the fixed iron 11. In other words, in the tripping device 1 of this embodiment, the tripping force F2 fluctuates less with respect to the amount of movement of the moving iron 12 toward the fixed iron 11 (has a flat characteristic). Here, the amount by which the pushing portion 14 pushes the latch portion 3 (hereinafter also referred to as the "latch amount") is proportional to the amount of movement of the moving iron 12 toward the fixed iron 11. Therefore, in the tripping device 1 of this embodiment, the tripping force F2 fluctuates less with respect to the latch amount. Therefore, the tripping device 1 of this embodiment has the advantage of being less susceptible to the effect of the latch amount and being able to stably open the contacts 2. In other words, the tripping device 1 of this embodiment has the advantage of being highly robust against the latch amount. Here, "robustness" refers to the degree of resistance to external influences.

[0077] More specifically, the advantages of the tripping device 1 of this embodiment will be described with reference to Figure 8. Graph G1 in Figure 8 shows the change in tripping force F2 depending on the latch amount in the tripping device 1 of this embodiment. On the other hand, graph G2 in Figure 8 shows the change in tripping force F2 depending on the latch amount in a comparative tripping device A1 (see Figure 3) that has the same integrated size as the tripping device 1 of this embodiment. "Same size" here means, more specifically, that the plate thicknesses of the fixed iron piece 11 and the moving iron piece 12 in the tripping device 1 of this embodiment are substantially the same as the plate thicknesses of the fixed iron piece A11 and the moving iron piece A12 in the tripping device A1. Graph G3 in Figure 8 shows the change in tripping force F2 depending on the latch amount in a tripping device in which the plate thicknesses of the fixed iron piece A11 and the moving iron piece A12 are thicker than those of the tripping device A1 shown in Figure 3 (hereinafter simply referred to as a "thickened tripping device"). Graphs G1, G2, and G3 are calculated by magnetic field analysis.

[0078] According to graphs G1 and G2, in the tripping device A1 of the comparative example, the change (slope) in the tripping force F2 with respect to the latch amount is larger, and the tripping force F2 when the pushing portion A14 starts to move is smaller, compared to the tripping device 1 of the present embodiment. Therefore, in the tripping device A1 of the comparative example, if the initial gap between the pushing portion A14 and the latch portion A3 is narrow and it is difficult to increase the latch amount, it is thought that the load applied by the pushing portion A14 to the latch portion A3 due to the tripping force F2 will be smaller. In other words, in the tripping device A1 of the comparative example, it is thought that the contacts may not be able to be released even if an abnormal current flows through the fixed contact plate A81.

[0079] However, in the tripping device 1 of this embodiment, as shown in graphs G1 and G2, the change (slope) of the tripping force F2 with respect to the latch amount is smaller and the tripping force F2 is larger when the pushing portion 14 starts to move, compared to the tripping device A1 of the comparative example. Therefore, even if the initial gap between (the contact portion 142 of) the pushing portion 14 and (the end 33 of) the latch portion 3 is narrow and it is difficult to increase the latch amount, the load that the pushing portion 14 applies to the latch portion 3 due to the tripping force F2 becomes large. In other words, the tripping device 1 of this embodiment has the advantage that, when an abnormal current flows through the fixed contact plate 81, the contact portion can be tripped even if the initial gap between (the contact portion 142 of) the pushing portion 14 and (the end 33 of) the latch portion 3 is narrow.

[0080] Furthermore, in the tripping device 1 of this embodiment, according to graphs G1 and G3, the tripping force F2 when the pushing portion 14 starts to move is substantially the same (more specifically, slightly larger) as that of a tripping device with an increased plate thickness. In other words, the tripping device 1 of this embodiment has the advantage of being able to be made smaller than a tripping device with substantially the same tripping force F2 when the pushing portion 14 starts to move.

[0081] (4) Modifications The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. The following modifications may be realized in appropriate combination. The same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0082] (4-1) First Modification In the above-described embodiment, the first surface X1 and the second surface X2 are flat surfaces facing each other. However, as shown in FIG. 9 , in a tripping device 1a of the first modification, the first surface X1a and the second surface X2a may be surfaces having the same concave-convex shape. More specifically, the first surface X1a has concave-convex surfaces X11a, which are flat surfaces. Similarly, the second surface X2a has concave-convex surfaces X21a, which are flat surfaces. The surfaces X11a and X21a have the same dimensions when viewed from the left-right direction. The "surfaces having a concave-convex shape" here refer to surfaces having a shape with multiple pointed portions lined up along the plane direction of the first surface X1a and the second surface X2a, i.e., a so-called jagged shape, when viewed from the left-right direction.

[0083] The movable iron piece 12a is configured so that, while moving toward the fixed iron piece 11a, each surface X21a of the concave-convex shape of the second surface X2a remains parallel to the opposing surface X11a of the concave-convex shape of the first surface X1a. In other words, the movable iron piece 12a is configured so that each surface X21a of the concave-convex shape of the second surface X2a remains parallel to the opposing surface X11a of the concave-convex shape of the first surface X1a while moving toward the fixed iron piece 11a.

[0084] With the above configuration, the surface area of ​​each of the first surface X1a and the second surface X2a can be increased. As a result, the tripping device 1a of the first modified example has the effect of increasing the magnitude of the attractive force with which the fixed iron piece 11 attracts the movable iron piece 12. In other words, the tripping device 1a of the first modified example has the advantage of increasing the tripping force generated by the movement of the movable iron piece 12 toward the fixed iron piece 11.

[0085] (4-2) Other Modifications Other modifications of the above-described embodiment are listed below. The following modifications may be implemented in appropriate combination.

[0086] The pushing portion 14 is formed of a material lighter than the movable iron piece 12, but may be formed of a magnetic material. For example, the pushing portion 14 may be formed of the same material as the movable iron piece 12, which is formed of a magnetic material. Note that when the pushing portion 14 is formed integrally with the holder 13, the holder 13 and the pushing portion 14 may be formed of a magnetic material. Also, the pushing portion 14 may be formed of a magnetic material lighter than the movable iron piece 12. The above configuration has the advantage of reducing the magnetic resistance of the movable iron piece 12 and increasing the force with which the fixed iron piece 11 attracts the movable iron piece 12.

[0087] In the above embodiment, both of the two terminals 7 are screw terminals, but this is not particularly limited. At least one of the two terminals 7 may be a terminal with a so-called quick-connect structure that can be connected without using screws.

[0088] (Summary) A first aspect of the tripping device (1, 1a) is a tripping device that, when an abnormality occurs in the power supplied from an external power source to a load via the contact portion (2), moves the latch portion (3) from a latched position to a non-latching position, thereby opening the contact portion (2). The tripping device (1, 1a) includes a fixed iron piece (11, 11a), a movable iron piece (12, 12a), and a pushing portion (14). The movable iron piece (12, 12a) is configured to move toward the fixed iron piece (11, 11a) when an abnormality occurs. The pushing portion (14) pushes the latch portion (3) from the latched position to the non-latching position in conjunction with the movable iron piece (12, 12a) moving toward the fixed iron piece (11, 11a). The movable iron pieces (12, 12a) have second surfaces (X2, X2a) that face the first surfaces (X1, X1a) of the fixed iron pieces (11, 11a). The movable iron pieces (12, 12a) are configured such that the second surfaces (X2, X2a) remain parallel to the first surfaces (X1, X1a) while moving toward the fixed iron pieces (11, 11a).

[0089] This embodiment has the advantage that a strong pulling force is generated when the movable iron pieces (12, 12a) move toward the fixed iron pieces (11, 11a).

[0090] In the tripping device (1, 1a) of the second aspect, in the first aspect, the pushing section (14) has a plurality of links (15) that movably hold the armature (12, 12a). Each of the plurality of links (15) performs a circular motion around a second end (152) opposite to a first end (151) that holds the armature (12, 12a) while the armature (12, 12a) moves toward the fixed armature (11, 11a). The radius of the circular motion performed by each of the plurality of links (15) is the same.

[0091] This aspect has the advantage that it is easier to configure the second surface (X2, X2a) to remain parallel to the first surface (X1, X1a) while the movable iron piece (12, 12a) is moving toward the fixed iron piece (11, 11a).

[0092] In the tripping device (1, 1a) of the third aspect, each of the plurality of links (15) in the second aspect has the same shape.

[0093] This embodiment has the advantage that parts can be shared among a plurality of links (15).

[0094] In the tripping device (1, 1a) of the fourth aspect, in any one of the first to third aspects, the pushing portion (14) is formed of a material lighter than the movable iron piece (12, 12a).

[0095] This embodiment has the advantage that the tripping force generated by the movement of the movable iron pieces (12, 12a) toward the fixed iron pieces (11, 11a) can be increased.

[0096] In a fifth aspect of the tripping device (1, 1a), in any one of the first to fourth aspects, the fixed iron piece (11, 11a) and the movable iron piece (12, 12a) are made of a magnetic material, and the movable iron piece (12, 12a) is configured to move toward the fixed iron piece (11, 11a) when an abnormality occurs by magnetizing the fixed iron piece (11, 11a) and the movable iron piece (12, 12a).

[0097] This embodiment has the advantage that the structure of the tripping device (1, 1a) can be simplified.

[0098] The tripping device (1, 1a) of the sixth aspect is the fifth aspect, in which the pushing portion (14) is made of a magnetic material.

[0099] This embodiment has the advantage that the magnetic resistance of the movable iron pieces (12, 12a) is reduced, and the force with which the fixed iron pieces (11, 11a) attract the movable iron pieces (12, 12a) is increased.

[0100] A seventh aspect of the tripping device (1a) is any one of the first to sixth aspects, in which the first surface (X1a) and the second surface (X2a) have the same concave-convex shape. The movable iron piece (12a) is configured so that, while moving toward the fixed iron piece (11a), each surface (X21a) of the concave-convex shape of the second surface (X2a) remains parallel to the opposing surface (X11a) of the concave-convex shape of the first surface (X1a).

[0101] This embodiment has the advantage that the tripping force generated by the moving iron pieces (12, 12a) moving toward the fixed iron pieces (11, 11a) is increased.

[0102] The tripping device (1, 1a) of an eighth aspect is any one of the first to seventh aspects, in which the pushing portion (14) has a holder (13) to which the movable iron piece (12, 12a) is attached. The holder (13) is plate-shaped.

[0103] This embodiment has the advantage that the movable iron pieces (12, 12a) can move easily.

[0104] A circuit breaker (10) of a ninth aspect includes a tripping device according to any one of the first to eighth aspects, a first terminal unit (7A), a second terminal unit (7B), a contact unit (2), and a latch unit (3). The first terminal unit (7A) is electrically connected to an external power source. The second terminal unit (7B) is electrically connected to a load. The contact unit (2) is inserted into an electrical path between the first terminal unit (7A) and the second terminal unit (7B). The latch unit (3) opens the contact unit (2) by being pushed from a latched position to a non-latching position by a push-in unit (14).

[0105] This embodiment has the advantage of being able to provide a circuit breaker that generates a strong tripping force when the movable iron piece (12, 12a) moves toward the fixed iron piece (11, 11a).

[0106] A distribution board (100) of a tenth aspect includes the circuit breaker (10) according to the ninth aspect and a cabinet (93) that houses the circuit breaker (10).

[0107] This embodiment has the advantage of being able to provide a distribution board that generates a strong pull-out force when the movable iron pieces (12, 12a) move toward the fixed iron pieces (11, 11a).

[0108] 100 Distribution board 10 Circuit breaker 1, 1a Tripping device 2 Contact portion 3 Latch portion 7A First terminal portion 7B Second terminal portion 11, 11a Fixed iron piece 12, 12a Movable iron piece 13 Holder 14 Push-in portion 15 Link 151 First end 152 Second end 93 Cabinet X1, X1a First surface X2, X2a Second surface X11a Surface X21a Surface

Claims

1. A tripping device that opens a contact part by moving a latch part from a latched position to a non-latching position when an abnormality occurs in the power supplied from an external power source to a load via a contact part, comprising: a fixed iron piece; a movable iron piece configured to move toward the fixed iron piece when the abnormality occurs; and a pushing part that moves in conjunction with the movable iron piece moving toward the fixed iron piece and pushes the latch part from the latched position to the non-latching position, wherein the movable iron piece has a second surface that faces a first surface of the fixed iron piece, and is configured so that the second surface remains parallel to the first surface while moving toward the fixed iron piece.

2. The tripping device as described in claim 1, wherein the pushing section has a plurality of links that movably hold the movable iron piece, each of the plurality of links performs a circular motion around a second end opposite to a first end that holds the movable iron piece while the movable iron piece moves toward the fixed iron piece, and the radius of the circular motion performed by each of the plurality of links is the same.

3. The tripping device according to claim 2, wherein each of said plurality of links has the same shape.

4. The tripping device according to any one of claims 1 to 3, wherein the pushing portion is formed of a material lighter than the movable iron piece.

5. A tripping device as claimed in any one of claims 1 to 4, wherein the fixed iron piece and the movable iron piece are formed from a magnetic material, and the movable iron piece is configured to move towards the fixed iron piece as a result of the fixed iron piece and the movable iron piece being magnetized when the abnormality occurs.

6. The tripping device according to claim 5, wherein the pushing portion is made of a magnetic material.

7. A tripping device as claimed in any one of claims 1 to 6, wherein the first surface and the second surface each have the same concave-convex shape, and the movable iron piece is configured such that, while moving towards the fixed iron piece, each surface of the concave-convex shape of the second surface remains parallel to the opposing surface of the concave-convex shape of the first surface.

8. The tripping device according to any one of claims 1 to 7, wherein the pushing portion has a holder to which the movable iron piece is attached, and the holder is plate-shaped.

9. A circuit breaker comprising: a tripping device as claimed in any one of claims 1 to 8; a first terminal portion electrically connected to the external power supply; a second terminal portion electrically connected to the load; a contact portion inserted in an electric path between the first terminal portion and the second terminal portion; and a latch portion which opens the contact portion by being pushed from the latched position to the non-latched position by the pushing portion.

10. A distribution board comprising: a circuit breaker according to claim 9; and a cabinet that houses the circuit breaker.

Images