Description:
Technical Field
[0001] The present disclosure generally relates to a tripping device, a circuit breaker, and a distribution board, and more particularly relates to tripping device configured to open a contact portion when abnormal electrical conditions occur and a circuit breaker and distribution board, each including such a tripping device.

Background Art
[0002] JP 2008-130381 A discloses a circuit breaker including a fixed iron piece, a moving iron piece, and an elastic member. The fixed iron piece is formed by fixing a moving electromagnetic piece onto, and disposing the moving electromagnetic piece in parallel with, a strip plate extended from a power supply side terminal fitting. The moving iron piece is arranged to face the fixed iron piece with the strip interposed between them and open and close with respect to the fixed iron piece. The elastic member is provided to return the moving iron piece to its open position. In this circuit breaker, the moving iron piece is mounted onto the body of the elastic member. A protruding coupling piece is pivotably mounted onto the right and left end portions of the fixed iron piece across the strip in the rightward/leftward direction. This circuit breaker is configured to cause the moving iron piece to pivot in the closing direction with magnetic force generated when an excessive amount of current flows through an electrical path, thereby allowing the user to operate its tripping member.
[0003] A tripping device included in such a circuit breaker sometimes includes an indirectly heated bimetal plate instead of a directly heated bimetal piece (bimetal plate). In that case, the indirectly heated bimetal plate does not generate heat in itself, thus making it difficult to ensure a temperature high enough to trip the indirectly heated bimetal plate.

Summary of Invention
[0004] It is therefore an object of the present disclosure to provide a tripping device, a circuit breaker, and a distribution board, all of which make it easier to ensure a temperature high enough to trip an indirectly heated bimetal plate.
[0005] A tripping device according to an aspect of the present disclosure is configured to open a contact portion by displacing a latch portion from a latched position to a non-latched position when abnormal conditions occur to electricity being supplied from an external power supply to a load via the contact portion. The tripping device includes a fixed iron piece, a moving iron piece, a push-in portion, an electrical path, and an indirectly heated bimetal plate. The moving iron piece is configured to move toward the fixed iron piece when the abnormal conditions occur. The push-in portion pushes in the latch portion from the latched position to the non-latched position synchronously with movement of the moving iron piece toward the fixed iron piece. The electrical path is interposed between a part of the fixed iron piece and the moving iron piece to supply the electricity. The bimetal plate is configured to, when deformed under heat generated by the electrical path, displace the push-in portion to the point of pushing in the latch portion from the latched position toward the non-latched position. The bimetal plate is interposed between the part of the fixed iron piece and the moving iron piece.
[0006] A circuit breaker according to another aspect of the present disclosure includes the tripping device described above, the contact portion, and the latch portion. The contact portion is inserted into the electrical path. The latch portion opens the contact portion when pushed in by the push-in portion from the latched position to the non-latched position.
[0007] A distribution board according to still another aspect of the present disclosure includes the circuit breaker described above; and a cabinet housing the circuit breaker inside.

Brief Description of Drawings
[0008] FIG. 1 is a plan view illustrating, with a first block removed, an internal configuration of a circuit breaker according to an exemplary embodiment in a state where its contact portion is closed;
FIG. 2 is a plan view illustrating, with the first block removed, an internal configuration of the circuit breaker in a state where its contact portion is opened;
FIG. 3 illustrates the appearance of a distribution board including the circuit breaker;
FIG. 4 is a perspective view of the circuit breaker;
FIG. 5 is a perspective view illustrating the appearance of a tripping device included in the circuit breaker; and
FIG. 6 is a cross-sectional view of the tripping device included in the circuit breaker.

Description of Embodiments
[0009] Note that the embodiment to be described below and its variations are only an exemplary one of various embodiments of the present disclosure and its variations and should not be construed as limiting. Rather, the exemplary embodiment and its variations may be readily modified in various manners depending on a design choice or any other factor without departing from a true spirit and scope of the present disclosure. The drawings to be referred to in the following description of embodiments and their variations are all schematic representations. Thus, the ratio of the dimensions (including thicknesses) of respective constituent elements illustrated on the drawings does not always reflect their actual dimensional ratio.
[0010] (Embodiment)
(1) Overview
First, an overview of a tripping device 1 according to an exemplary embodiment will be described with reference to FIGS. 1 and 2.
[0011] A tripping device 1 according to this embodiment is provided inside a circuit breaker 10. The tripping device 1 is configured to open a contact portion 2 by displacing a latch portion 3 from a latched position to a non-latched position when abnormal conditions occur to electricity being supplied from an external power supply to a load via the contact portion 2. As used herein, the “latched position” refers to a position where the latch portion 3 closes the contact portion 2 as shown in FIG. 1. The “non-latched position” as used herein refers to a position where the latch portion 3 opens the contact portion 2 as shown in FIG. 2.
[0012] The tripping device 1 includes a fixed iron piece 11, a moving iron piece 12, a push-in portion 14, an electrical path L1, and an indirectly heated bimetal plate 4 as shown in FIGS. 1 and 2. The moving iron piece 12 is configured to move toward the fixed iron piece 11 when abnormal conditions occur to the electricity being supplied from an external power supply to a load via the contact portion 2. The push-in portion 14 pushes in the latch portion 3 from the latched position to the non-latched position synchronously with movement of the moving iron piece 12 toward the fixed iron piece 11. The electrical path L1 is provided to supply the electricity from the external power supply to the load via the contact portion 2. The electrical path L1 is interposed between a part of the fixed iron piece 11 and the moving iron piece 12. The bimetal plate 4 is configured to, when deformed under the heat generated by the electrical path L1, displace the push-in portion 14 to the point of pushing in the latch portion 3 from the latched position toward the non-latched position. The bimetal plate 4 is interposed between the part of the fixed iron piece 11 and the moving iron piece 12. As used herein, the “indirectly heated bimetal plate” refers to a bimetal plate to be deformed under the heat generated by a member disposed around itself (i.e., a member other than itself), unlike a directly heated bimetal plate to be deformed under the heat generated by itself.
[0013] As can be seen, the tripping device 1 according to this embodiment allows the heat generated by the electrical path L1 to be shut off by the fixed iron piece 11 and the moving iron piece 12. Thus, the tripping device 1 according to this embodiment achieves the advantage of making it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate 4.
[0014] (2) Detailed configuration
Next, a detailed configuration for the tripping device 1, circuit breaker 10, and distribution board 100 according to this embodiment will be described with reference to FIGS. 1–6.
[0015] (2-1) Distribution board
The distribution board 100 according to this embodiment includes a main circuit breaker 91, a plurality of (e.g., twelve in the example shown in FIG. 3) branch circuit breakers 92, a cabinet 93, and an outer lid (not shown) shown in FIG. 3. In this embodiment, each of the plurality of branch circuit breakers 92 is the circuit breaker 10. The distribution board 100 may be installed, for example, in a dwelling house (or a non-dwelling house).
[0016] The cabinet 93 may be made of a synthetic resin, for example. The cabinet 93 is formed in the shape of a box with an open front surface as shown in FIG. 3 and is used to be mounted on a wall of a dwelling house, for example. The cabinet 93 houses the main circuit breaker 91 and the plurality of branch circuit breakers 92 (i.e., circuit breakers 10). More specifically, the cabinet 93 has a space for housing the main circuit breaker 91 and the plurality of branch circuit breakers 92 (i.e., circuit breakers 10). The outer lid is attached to the cabinet 93 to be movable between a position where the outer lid closes the front surface of the cabinet 93 and a position where the outer lid opens the front surface of the cabinet 93.
[0017] The main circuit breaker 91 includes a primary side terminal and a secondary side terminal. An external power supply is electrically connected to the primary side terminal of the main circuit breaker 91. As used herein, the “external power supply” refers to a power supply that supplies electricity to a load and may be, for example, a grid power supply (i.e., a commercial power supply). The distribution board 100 according to this embodiment is supposed to adopt the single-phase three-wire system as its power distribution system. Thus, lead wires of the single phase three wire system of the grid power supply (commercial power supply) are electrically connected to the primary side terminal of the main circuit breaker 91. That is to say, in this embodiment, the main circuit breaker 91 has two hot wires and one neural line. On the other hand, the respective circuit breakers 10 are electrically connected to the secondary side terminal of the main circuit breaker 91.
[0018] The plurality of circuit breakers 10 are divided into two groups which are respectively arranged over and under an electrically conductive bar of the neutral line. Each group of circuit breakers 10 (e.g., six circuit breakers 10 in the example shown in FIG. 3) are arranged side by side in the rightward/leftward direction. Each circuit breaker 10 also has a primary side terminal and a secondary side terminal.
[0019] The secondary side terminal of the main circuit breaker 91 is electrically connected to the primary side terminal of each circuit breaker 10. That is to say, the external power supply is electrically connected to the primary side terminal of each circuit breaker 10 via the main circuit breaker 91. In addition, one or more loads are electrically connected to the secondary side terminal of each circuit breaker 10. As used herein, the “load” includes not only electrical equipment such as lighting fixtures and a hot water supply system but also wiring devices such as outlets and wall switches. The circuit breakers 10 will be described later in further detail in the “(2–2) Circuit breaker” section.
[0020] (2–2) Circuit breaker
(2–2–1) Overall configuration
The circuit breaker 10 includes the tripping device 1, the contact portion 2, the latch portion 3 (including an operating handlebar 6), a body 5, a pair of terminal portions 7, a fixed contact plate 81, and a braided wire 82 as shown in FIGS. 1 and 2.
[0021] The circuit breaker 10 has the capability of shutting off a current flowing from an external power supply to the load (i.e., the current flowing through the main circuit) by turning the contact portion 2 from the closed position to the opened position upon detecting any short-circuit current or an overcurrent such as an overload current. In addition, the circuit breaker 10 is also configured to turn the contact portion 2 from the closed position to the opened position, and vice versa, in response to a command entered manually through the operating handlebar 6. The user may, if he or she can confirm safe conditions after the contact portion 2 has been opened upon the detection of an abnormal current, for example, close the contact portion 2 by turning the operating handlebar 6. The main circuit according to this embodiment is the electrical path L1 through which electricity is supplied from the external power supply to the load. The main circuit is the electrical path L1 between a first terminal portion 7A, which is one of pair of terminal portions 7, and a second terminal portion 7B, which is the other of the pair of terminal portions 7 as will be described later. The electrical path L1 (i.e., the main circuit) is made up of the fixed contact plate 81, the latch portion 3, the braided wire 82, and other components.
[0022] (2–2–2) Body
The body 5 has the shape of a generally compressed, substantially rectangular parallelepiped box as shown in FIG. 4. In the following description, the direction aligned with the thickness of the body 5 will be hereinafter referred to as a “rightward/leftward direction” for the circuit breaker 10. Also, in the following description, the direction in which the pair of terminal portions 7 are arranged one on top of the other as shown in FIG. 1 will be hereinafter referred to as an “upward/downward direction.” In the following description, the “downside” herein refers to the downside of the circuit breaker 10 when viewed from in front of the circuit breaker 10. In the same way, the “right side” herein refers to the right of the circuit breaker 10 when viewed from in front of the circuit breaker 10 and the “left side” herein refers to the left of the circuit breaker 10 when viewed from in front of the circuit breaker 10. Furthermore, in the following description, a direction perpendicular to both the upward/downward direction and the rightward/leftward direction will be hereinafter referred to as a “forward/backward direction.” One side, provided with the operating handlebar 6, of the body 5 will be hereinafter referred to as the “front side” of the body 5. Note that these directions should not be construed as limiting the directions in which the circuit breaker 10 is supposed to be used.
[0023] The body 5 includes a first block 5A (right-side block) and a second block 5B (left-side block) as shown in FIG. 4. The first block 5A and the second block 5B are made of a synthetic resin material with electrical insulation properties.
[0024] The body 5 houses the tripping device 1, the contact portion 2, the latch portion 3, the bimetal plate 4, the operating handlebar 6, the pair of terminal portions 7, the fixed contact plate 81, and the braided wire 82 inside itself. In addition, the body 5 supports the operating handlebar 6 such that a part of the operating handlebar 6 (i.e., its lever 61) is exposed through its front wall 55 to the external space as shown in FIGS. 1, 2, and 4. As shown in FIG. 4, the front wall 55 protrudes forward to have its middle portion in the upward/downward direction raised, and the lever 61 is exposed to the external space through a window hole 56 of the raised middle portion.
[0025] The first block 5A and the second block 5B are formed in the shape of a substantially rectangular parallelepiped box with their surfaces facing each other opened. The first block 5A and the second block 5B are combined together by abutting the first block 5A and the second block 5B on each other.
[0026] (2–2–3) Terminal portions
As shown in FIGS. 1 and 2, the first terminal portion 7A which is one of the pair of terminal portions 7 is housed in an upper end portion inside the body 5 and the second terminal portion 7B which is the other of the pair of terminal portions 7 is housed in the lower end portion inside the body 5. In the following description, an electric cable on the external power supply (such as a commercial power supply) side is supposed to be electrically connected to the first terminal portion 7A and an electric cable on the load side is supposed to be electrically connected to the second terminal portion 7B. That is to say, the first terminal portion 7A is supposed to be the primary side terminal, to which the secondary side terminal of the main circuit breaker 91 is electrically connected, and the second terminal portion 7B is supposed to be the secondary side terminal, to which the load is electrically connected. Alternatively, an electric cable on the load side may be electrically connected to the first terminal portion 7A and an electric cable on the external power supply side may be electrically connected to the second terminal portion 7B.
[0027] The first terminal portion 7A and the second terminal portion 7B are so-called “pillar terminals (screw terminals)” which may be hardwired with screws, for example. As shown in FIG. 1, the first terminal portion 7A includes a terminal plate 71, a terminal fitting 72, and a terminal screw 73. The second terminal portion 7B includes a terminal fitting 72 and a terminal screw 73.
[0028] The terminal plate 71 is formed in the shape of a substantially L-plate out of a metallic plate with electrical conductivity. The terminal plate 71 is fixed inside the body 5.
[0029] The terminal fitting 72 is formed in the shape of a square tube out of a metallic plate with electrical conductivity. The terminal fitting 72 has its axis defined in the upward/downward direction and has both ends thereof in the upward/downward direction opened. The terminal fitting 72 of the first terminal portion 7A is movable within a predetermined range in the forward/backward direction inside the body 5 with a part (i.e., a protruding piece 711) of the terminal plate 71 inserted thereto. On the other hand, the terminal fitting 72 of the second terminal portion 7B is movable within a predetermined range in the forward/backward direction inside the body 5 with a part (i.e., a protruding piece 811) of the fixed contact plate 81 inserted thereto. The terminal fitting 72 has a screw hole into which the terminal screw 73 is screwed. The body 5 has a plurality of (i.e., two in total) insert holes 51, into which the electric cables are inserted, respectively, through respective portions of the body 5, each of which overlaps with the gap between the protruding piece 711 (or the protruding piece 811) and the bottom wall of the terminal fitting 72 when viewed in the upward/downward direction.
[0030] Each terminal screw 73 is housed inside the body 5 with its tip screwed into the screw hole of its corresponding terminal fitting 72. The body 5 has a plurality of (i.e., two in total) holes 52 provided through its front wall 55. Each of these holes 52 is arranged to overlap with the head of a corresponding one of the terminal screws 73 when viewed in the forward/backward direction. Each of these holes 52 exposes the head of the corresponding terminal screw 73 without allowing the terminal screw 73 to drop off.
[0031] In the first terminal portion 7A, fastening the terminal screw 73 by turning the tip of a tool such as a screwdriver inserted through the hole 52 with an electric cable on the external power supply side inserted through the insert hole 51 into the gap between the protruding piece 711 and the bottom wall of the terminal fitting 72 allows the terminal fitting 72 to move forward, thus narrowing the distance between the protruding piece 711 and the bottom wall of the terminal fitting 72. As a result, the electric cable on the external power supply side inserted into the gap may be connected to the terminal portion 7.
[0032] In the same way, in the second terminal portion 7B, fastening the terminal screw 73 by turning the tip of a tool such as a screwdriver inserted through the hole 52 with an electric cable on the load side inserted through the insert hole 51 into the gap between the protruding piece 811 and the bottom wall of the terminal fitting 72 allows the terminal fitting 72 to move forward, thus narrowing the distance between the protruding piece 811 and the bottom wall of the terminal fitting 72. As a result, the electric cable on the load side inserted into the gap may be connected to the terminal portion 7.
[0033] (2–2–4) Contact portion
The contact portion 2 is configured to be opened when abnormal conditions occur to the electricity being supplied from the external power supply to the load via the contact portion 2. More specifically, the contact portion 2 is configured to be opened in response to the occurrence of an abnormal current (e.g., a leakage current, a short-circuit current, and an overload current in this example) in the main circuit and thereby switch the main circuit from the electrically conductive state to an electrically non-conductive state. The contact portion 2 is inserted to the electrical path L1 between the first terminal portion 7A and the second terminal portion 7B.
[0034] As shown in FIGS. 1 and 2, the contact portion 2 includes a fixed contact 2A and a moving contact 2B configured to selectively come into, or out of, contact with the fixed contact 2A. FIG. 1 illustrates a state where the contact portion 2 is closed. On the other hand, FIG. 2 illustrates a state where the contact portion 2 is opened.
[0035] The fixed contact 2A is provided for the fixed contact plate 81. More specifically, the fixed contact 2A is a recess provided for the fixed contact plate 81. Alternatively, the fixed contact 2A may also be a projection provided for the fixed contact plate 81. The fixed contact plate 81 is made of a material with low electrical resistance such as iron or copper. The fixed contact plate 81 forms part of the electrical path L1 (i.e., the main circuit).
[0036] The moving contact 2B is provided at one end of an arm 31 (moving armature) of the latch portion 3 formed by subjecting a metallic plate to punching and bending. The moving contact 2B forms an integral part of the arm 31. Alternatively, the moving contact 2B may be provided separately from the arm 31 and fixed to one end of the arm 31. The arm 31 forms part of the electrical path L1.
[0037] The arm 31 is pivotable, on a shaft 32 provided at the other end of the arm 31, between a position where the moving contact 2B is in contact with the fixed contact 2A (refer to FIG. 1) and a position where the moving contact 2B is out of contact with the fixed contact 2A (refer to FIG. 2). One end of the braided wire 82 is fixed to a middle portion of the arm 31. The braided wire 82 forms part of the main circuit. The other end of the braided wire 82 is fixed to the terminal plate 71 of the first terminal portion 7A. The braided wire 82 forms part of the electrical path L1.
[0038] In the state where the contact portion 2 is closed, the electricity supplied (i.e., output) from the external power supply to the first terminal portion 7A passes through the electrical path L1 to be supplied (i.e., input) to the load through the second terminal portion 7B. More specifically, the electricity output from the external power supply to the first terminal portion 7A passes through the electrical path L1 (specifically, the braided wire 82, the latch portion 3, and the fixed contact plate 81 in this order) to be input to the load through the second terminal portion 7B.
[0039] (2–2–5) Latch portion
The latch portion 3 is configured to open or close the contact portion 2 in response to either an opening operation (turn-off operation) or a closing operation (turn-on operation). More specifically, the latch portion 3 is configured to maintain either a state where the moving contact 2B is in contact with the fixed contact 2A (refer to FIG. 1) or a state where the moving contact 2B is out of contact with the fixed contact 2A (refer to FIG. 2) in response to either the opening operation or the closing operation. When the latch portion 3 is in the latched position (refer to FIG. 1), the latch portion 3 closes the contact portion 2. That is to say, the latch portion 3 maintains the state where the moving contact 2B is in contact with the fixed contact 2A. On the other hand, when the latch portion 3 is in the non-latched position (refer to FIG. 2), the latch portion 3 opens the contact portion 2. That is to say, the latch portion 3 maintains the state where the moving contact 2B is out of contact with the fixed contact 2A.
[0040] Furthermore, as the latch portion 3 is pushed in by a push-in portion 14 (to be described later) of the tripping device 1 from the latched position toward the non-latched position, the latch portion 3 opens the contact portion 2. That is to say, the latch portion 3 maintains the state where the moving contact 2B is out of contact with the fixed contact 2A.
[0041] The latch portion 3 includes the operating handlebar 6, a plurality of latch members 30, and the arm 31. The operating handlebar 6 is supported pivotably by the body 5 with the lever (operating lever) 61 of the operating handlebar 6 protruding out of the body 5 through the window hole 56 (refer to FIG. 4) provided through the front wall 55 of the body 5. Each of the latch members 30 couples the operating handlebar 6 to the arm 31. As the operating handlebar 6 is turned, each of the latch members 30 causes the arm 31 to move synchronously. The operating handlebar 6 is pivotable between an ON position where the contact portion 2 is closed (refer to FIG. 1) and an OFF position where the contact portion 2 is opened (refer to FIG. 2).
[0042] In FIG. 1, the contact portion 2 is closed and the lever 61 of the operating handlebar 6 is tilted upward. In FIG. 2, on the other hand, the contact portion 2 is opened and the lever 61 of the operating handlebar 6 is tilted downward.
[0043] (2–2–6) Tripping device
The tripping device 1 is configured to, when abnormal conditions occur to the electricity being supplied from the external power supply to the load via the contact portion 2, drive the latch portion 3 and thereby open the contact portion 2 compulsorily (i.e., to trip the moving contact 2B from the fixed contact 2A). More specifically, the tripping device 1 is configured to, when the main circuit detects an abnormal current, drive the latch portion 3 and thereby open the contact portion 2 compulsorily.
[0044] The tripping device 1 includes the fixed iron piece 11, the moving iron piece 12, a holder 13, the push-in portion 14, and the bimetal plate 4 as shown in FIGS. 5 and 6. The tripping device 1 is disposed on the electrical path L1. In this embodiment, the tripping device 1 is disposed on the fixed contact plate 81 that forms part of the electrical path L1.
[0045] As shown in FIG. 6, the fixed iron piece 11 has a first surface X1, while the moving iron piece 12 has a second surface X2 facing the first surface X1. The electrical path L1 is interposed between the first surface X1 and the second surface X2. In this embodiment, the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12 face each other substantially in the forward/backward direction.
[0046] The fixed iron piece 11 is made of a magnetic material and is a generally U-shaped plate member as shown in FIG. 6. More specifically, the fixed iron piece 11 has a first part 111, a second part 112, and a third part 113. The first part 111 is a plate member in the shape of a rectangular flat plate and has a thickness intersecting (e.g., at right angles in this example) with the rightward/leftward direction as shown in FIG. 5. In this embodiment, the first part 111 is housed inside the body 5 such that the upper end thereof is located forward of the lower end thereof as shown in FIGS. 1 and 2. That is to say, in this embodiment, the thickness of the first part 111 is not aligned with, but forms a small tilt angle with respect to, the forward/backward direction. The first part 111 has the first surface X1 and also has a first end 1111 (right end) and a second end 1112 (left end) as shown in FIG. 6. The first surface X1 is the front surface of the first part 111. The second part 112 is a plate member having a substantially rectangular shape which protrudes forward from the first end 1111 (right end) of the first part 111 along the thickness of the first part 111 as shown in FIG. 6. Likewise, the third part 113 is a plate member having a substantially rectangular shape which protrudes forward from the second end 1112 (left end) of the first part 111 along the thickness of the first part 111 as shown in FIG. 6. The second part 112 and the third part 113 face each other in the rightward/leftward direction. As shown in FIG. 5, each of the second part 112 and the third part 113 includes a catching portion 114 to be caught by a rib (not shown) provided on the inner surface of the body 5. As used herein, the “part of the fixed iron piece 11” in the expression “interposed between a part of the fixed iron piece 11 and the moving iron piece 12” refers to the first part 111 of the fixed iron piece 11.
[0047] The fixed iron piece 11 is housed inside the body 5 such that the fixed contact plate 81 is inserted inside the fixed iron piece 11 as shown in FIGS. 5 and 6. More specifically, the fixed iron piece 11 is housed inside the body 5 such that the fixed contact plate 81 is inserted between the second part 112 and the third part 113 in the rightward/leftward direction.
[0048] The moving iron piece 12 is configured to, when abnormal conditions occur to the electricity being supplied from the external power supply to the load via the contact portion 2, move toward the fixed iron piece 11. The moving iron piece 12 is made of a magnetic material and is an elongate plate member having a rectangular shape. As shown in FIG. 1, the thickness of the moving iron piece 12 is not aligned with, but forms a small tilt angle with respect to, the forward/backward direction. The thickness of the moving iron piece 12 intersects with the thickness of the first part 111 of the fixed iron piece 11 when the moving iron piece 12 is viewed in the rightward/leftward direction. More specifically, when the moving iron piece 12 is viewed in the rightward/leftward direction before the moving iron piece 12 starts moving toward the fixed iron piece 11 (i.e., in the state where the contact portion 2 is closed), the thickness of the moving iron piece 12 intersects with the forward/backward direction at a large angle than the thickness of the first part 111 does. One surface located closer to the fixed iron piece 11 (i.e., the rear surface of the moving iron piece 12) which belongs to two surfaces facing each other along the thickness of the moving iron piece 12 is the second surface X2 (refer to FIG. 6) facing the first surface X1.
[0049] The moving iron piece 12 is housed inside the body 5 such that in the state where the contact portion 2 is closed, the clearance between the rear surface of the moving iron piece 12 and the front surface of the second part 112 of the fixed iron piece 11 gradually increases from the first end (i.e., the lower end) of the rear surface of the moving iron piece 12 toward the second end (upper end) thereof as shown in FIG. 1 when viewed in the rightward/leftward direction. In addition, the moving iron piece 12 is also housed inside the body 5 such that the fixed contact plate 81 (refer to FIGS. 5 and 6) is inserted between the moving iron piece 12 and the first part 111 of the fixed iron piece 11 along the thickness of the moving iron piece 12.
[0050] In this embodiment, the moving iron piece 12 is configured such that when the current value of the electricity supplied from the external power supply to the load becomes higher than a threshold value, a magnetic circuit passing through the fixed iron piece 11 and the moving iron piece 12 is formed and the fixed iron piece 11 and the moving iron piece 12 are magnetized, thereby generating magnetic attraction (magnetic force) with which the fixed iron piece 11 attracts the moving iron piece 12 to cause the moving iron piece 12 to move toward the fixed iron piece 11. More specifically, when the current value of the electricity flowing through the fixed contact plate 81 becomes higher than the threshold value, the fixed iron piece 11 and the moving iron piece 12 are housed around the fixed contact plate 81, and therefore, magnetized. As a result, the moving iron piece 12 moves toward the fixed iron piece 11. According to this configuration, there is no need to provide any structure for detecting the abnormal conditions of the electricity being supplied from the external power supply to the load or a structure for causing the fixed iron piece 11 to attract the moving iron piece 12 by a method other than using magnetic force, thus achieving the advantage of simplifying the configuration of the tripping device 1.
[0051] The holder 13 is a member on which the moving iron piece 12 is mounted. The holder 13 moves in synch with the moving iron piece 12 moving toward the fixed iron piece 11. That is to say, the holder 13 moves along with the moving iron piece 12 moving toward the fixed iron piece 11.
[0052] The holder 13 according to this embodiment includes a base portion 130, a mounting portion 131, a connection portion 132, and a return spring portion 133 as shown in FIG. 5. The base portion 130 according to this embodiment is a plate member having a substantially rectangular shape. The moving iron piece 12 is held on the rear surface of the base portion 130. The mounting portion 131 mounts the base portion 130 inside the body 5 to allow the base portion 130 to turn around a center point P1 (refer to FIGS. 1 and 2). The mounting portion 131 is provided at the lower end of the base portion 130. The mounting portion 131 according to this embodiment has the shape of a bar and is fitted into a boss 58 (refer to FIGS. 1 and 2) provided inside the body 5. The connection portion 132 is a portion to which the push-in portion 14 is connected. The connection portion 132 is provided at the upper end of the base portion 130. The return spring portion 133 may be configured as a coil spring, for example, and is provided over the front surface of the base portion 130. As the moving iron piece 12 moves toward the fixed iron piece 11, the return spring portion 133 is flexed, thereby producing elastic force that causes the moving iron piece 12 to move away from the fixed iron piece 11.
[0053] The moving iron piece 12 is mounted onto the holder 13, and therefore, is configured to be caused to turn around the center point P1 and move toward the fixed iron piece 11 by the attraction force generated when the current value of the electricity being supplied from the external power supply to the load becomes higher than a threshold value.
[0054] The push-in portion 14 pushes in the latch portion 3 from the latched position toward the non-latched position synchronously with the movement of the moving iron piece 12 toward the fixed iron piece 11. More specifically, the push-in portion 14 pushes the end portion 33 (refer to FIG. 1) of the latch portion 3 upward, thereby pushing in the latch portion 3 from the latched position toward the non-latched position. The push-in portion 14 according to this embodiment is formed integrally with the holder 13 and moves along with the holder 13 while the moving iron piece 12 is moving toward the fixed iron piece 11.
[0055] The push-in portion 14 is made of a material lighter than that of the moving iron piece 12. In this embodiment, the push-in portion 14 is formed integrally with the holder 13, and therefore, the holder 13 and the push-in portion 14 are made of a material lighter than that of the moving iron piece 12. As used herein, the “material lighter than that of the moving iron piece 12” refers to a material including a reinforced fiber such as polyamide (PA), polyamide imide (PAI), polyimide (PI), PEEK, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene (PE), ABS, polystyrene (PS), polypropylene (PP), acrylic (PMNA), polyacetal (POM), liquid crystal polymer (LCP), or melamine (MF). This configuration allows the moving iron piece 12 to move at a higher velocity toward the fixed iron piece 11, thus enabling the latch portion 3 to be pushed in more strongly from the latched position toward the non-latched position. That is to say, this configuration achieves the advantage of allowing the tripping device 1 to trip the moving contact 2B from the fixed contact 2A with stronger force. In other words, this configuration achieves the advantage of further enhancing the tripping force generated by the movement of the moving iron piece 12 toward the fixed iron piece 11.
[0056] The push-in portion 14 according to this embodiment includes a connection portion 141, a first part 142, a mounting portion 143, a second part 144, and a contact portion 145 as shown in FIG. 5.
[0057] Each of the first part 142 and the second part 144 is a plate member having the shape of a rectangular flat plate. The thickness of the first part 142 is generally aligned with the forward/backward direction. The thickness of the second part 144 is generally aligned with the upward/downward direction. A first end (lower end) of the first part 142 is provided with the connection portion 141 connected to the connection portion 132 of the holder 13. As shown in FIG. 5, the connection portion 132 of the holder 13 and the connection portion 141 of the push-in portion 14 are connected to each other by revolute joint. A second end (upper end) of the first part 142 is connected to a first end (front end) of the second part 144. The connection portion between the second end (upper end) of the first part 142 and the first end (front end) of the second part 144 is provided with the mounting portion 143. The mounting portion 143 is provided to mount the push-in portion 14 inside the body 5 to allow the push-in portion 14 to turn around a center point P2. The mounting portion 143 according to this embodiment has the shape of a bar and is fitted into a boss 59 (refer to FIGS. 1 and 2) provided inside the body 5. The contact portion 145 is provided at a second end (rear end) of the second part 144.
[0058] The contact portion 145 comes into contact with an end portion 33 of the latch portion 3 while the push-in portion 14 is pushing in the latch portion 3. The contact portion 145 according to this embodiment is a plate member having the shape of a rectangular flat plate. The thickness of the contact portion 145 according to this embodiment is generally aligned with the forward/backward direction. The contact portion 145 according to this embodiment is arranged to face the first part 142. That is to say, the push-in portion 14 according to this embodiment has a generally U-shape when viewed in the rightward/leftward direction. A catching portion 146 is provided at the tip of the push-in portion 14 according to this embodiment. The catching portion 146 catches the tip 42 (upper end, to be described later) of the bimetal plate 4 in a state where the bimetal plate 4 is deformed as shown in FIG. 2. The catching portion 146 according to this embodiment has a semicircular shape when viewed in the rightward/leftward direction.
[0059] The bimetal plate 4 is deformed under the heat generated by the electrical path L1 (i.e., the fixed contact plate 81 in this embodiment). That is to say, the bimetal plate 4 is an indirectly heated type. Specifically, when an overcurrent flows through the electrical path L1 due to an overload, for example, the temperature of the electrical path L1 increases, thus causing the bimetal plate 4 to be deformed due to the increase in the temperature of the electrical path L1. The bimetal plate 4 is a plate member having the shape of a rectangular flat plate. The thickness direction defined with respect to the bimetal plate 4 according to this embodiment intersects (e.g., at right angles in this embodiment) with the rightward/leftward direction as shown in FIG. 5.
[0060] The bimetal plate 4 has a connection end 41 and a tip 42 as shown in FIGS. 1 and 2. In the bimetal plate 4 according to this embodiment, the lower end thereof is the connection end 41 and the upper end thereof is the tip 42. The connection end 41 is connected to the electrical path L1. More specifically, the connection end 41 is connected to the fixed contact plate 81 that forms part of the electrical path L1. The bimetal plate 4 is fixed onto the fixed contact plate 81 by having the connection end 41 thereof connected to the fixed contact plate 81. The bimetal plate 4 protrudes from the connection end 41 toward the catching portion 146 of the push-in portion 14. The tip 42 of the bimetal plate 4 is in contact with the catching portion 146 as shown in FIG. 1 before the bimetal plate 4 is deformed.
[0061] When the heat generated by the electrical path L1 is transferred to the bimetal plate 4, the bimetal plate 4 is deformed to have its tip 42 bent (flexed) and displaced backward. Deforming the bimetal plate 4 in this manner makes the tip 42 of the bimetal plate 4 caught by the catching portion 146, thus causing the push-in portion 14 to move to push in the latch portion 3 from the latched position toward the non-latched position. The latch portion 3 being pushed in by the push-in portion 14 from the latched position toward the non-latched position opens the contact portion 2. That is to say, deformation of the bimetal plate 4 under the heat generated by the electrical path L1 causes the latch portion 3 to open the contact portion 2.
[0062] The bimetal plate 4 is interposed between the moving iron piece 12 and the electrical path L1. The electrical path L1 is interposed between the bimetal plate 4 and a part of the fixed iron piece 11. More specifically, the electrical path L1 is interposed between the bimetal plate 4 and the first part 111 of the fixed iron piece 11. That is to say, in the tripping device 1 according to this embodiment, the moving iron piece 12, the bimetal plate 4, the electrical path L1, and the fixed iron piece 11 are arranged in this order from the front end toward the rear end.
[0063] That is to say, the bimetal plate 4 and the electrical path L1 are arranged between the fixed iron piece 11 and the moving iron piece 12 as shown in FIG. 6. This configuration allows the heat generated by the electrical path L1 (e.g., the fixed contact plate 81 in this embodiment) to be shut off by the fixed iron piece 11 and the moving iron piece 12. Thus, the tripping device 1 according to this embodiment achieves the advantage of making it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate 4.
[0064] More specifically, the bimetal plate 4 and the electrical path L1 are arranged in the forward/backward direction between the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12. That is to say, the bimetal plate 4 and the electrical path L1 are arranged between the first surface X1 and second surface X2 that face each other. This configuration allows the heat generated by the electrical path L1 to be shut off more easily by the fixed iron piece 11 and the moving iron piece 12. Thus, the tripping device 1 according to this embodiment achieves the advantage of making it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate 4.
[0065] The bimetal plate 4 and the electrical path L1 are arranged parallel to the first surface X1 of the fixed iron piece 11. More specifically, the bimetal plate 4 and the electrical path L1 are arranged parallel to the first surface X1 of the fixed iron piece 11 between the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12. That is to say, the bimetal plate 4 and the part, located between the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12, of the electrical path L1 are arranged parallel to the first surface X1 of the fixed iron piece 11. In other words, the bimetal plate 4 and the part, located between the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12, of the electrical path L1 are parallel to each other and face each other along the thickness of the fixed iron piece 11. This configuration makes the clearance between the bimetal plate 4 and the part, located between the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12, of the electrical path L1 uniform, thus achieving the advantage of making the heat generated by the electrical path L1 transferrable more smoothly to the bimetal plate 4. As used herein, if something is “parallel to” something else, these two things do not have to be exactly parallel to each other but a very small angle (of ±2 degrees, for example) may be formed as a tolerance between them.
[0066] Furthermore, the bimetal plate 4 is interposed in the rightward/leftward direction between the second part 112 and third part 113 of the fixed iron piece 11 as shown in FIG. 6. This configuration allows the heat generated by the electrical path L1 to be further shut off by the second part 112 and third part 113 of the fixed iron piece 11. Thus, the tripping device 1 according to this embodiment achieves the advantage of making it even easier to ensure a temperature high enough to trip the indirectly heated bimetal plate 4.
[0067] As shown in FIG. 6, a first gap Y1 is left between the bimetal plate 4 and the electrical path L1. The first gap Y1 is a gap between the rear surface of the bimetal plate 4 and the front surface of the electrical path L1. More specifically, the first gap Y1 is a gap surrounded with the rear surface of the bimetal plate 4, the left surface of the second part 112 of the fixed iron piece 11, the front surface of the electrical path L1, and the right surface of the third part 113 of the fixed iron piece 11. This configuration achieves the advantage of making it easier to deform, when the heat generated by the electrical path L1 is transferred to the bimetal plate 4, the bimetal plate 4 to have its tip 42 bent (flexed) and displaced backward. That is to say, this configuration achieves the advantage of making the bimetal plate 4 deformable more smoothly.
[0068] In this embodiment, the first gap Y1 is left between the tip 42 of the bimetal plate 4 and the electrical path L1 as shown in FIG. 1. The electrical path L1 according to this embodiment is curved to be connected to the connection end 41 of the bimetal plate 4 and leave the first gap Y1 between the tip 42 of the bimetal plate 4 and the electrical path L1 itself. This configuration achieves the advantage of making it easier to deform, when the heat generated by the electrical path L1 is transferred to the bimetal plate 4, the bimetal plate 4 to have its tip 42 bent (flexed) around the connection end 41 and displaced backward. That is to say, this configuration achieves the advantage of making the bimetal plate 4 deformable more smoothly.
[0069] In addition, the electrical path L1 is interposed between the bimetal plate 4 and the fixed iron piece 11 and a second gap Y2 is left between the electrical path L1 and the fixed iron piece 11 as shown in FIG. 6. The second gap Y2 is a gap surrounded with the rear surface of the electrical path L1, the left surface of the second part 112 of the fixed iron piece 11, the front surface of the first part 111 of the fixed iron piece 11, and the right surface of the third part 113 of the fixed iron piece 11. This configuration achieves the advantage of allowing the heat generated by the electrical path L1 to be transferred to the fixed iron piece 11 less easily. In a circuit breaker according to a comparative example, the fixed iron piece is caught by a rib provided on an inner surface of the body, and therefore, allowing the heat generated by the electrical path to be transferred to the fixed iron piece would possibly cause an increase in the temperature of the body, i.e., the temperature of the circuit breaker. In contrast, the circuit breaker 10 according to this embodiment makes it less easy to transfer the heat generated by the electrical path L1 to the fixed iron piece 11, thus achieving the advantage of reducing an increase in the temperature of the circuit breaker 10.
[0070] (3) Advantages
In the tripping device 1 according to this embodiment, the bimetal plate 4 is interposed between a part (i.e., the first part 111) of the fixed iron piece 11 and the moving iron piece 12. This allows the heat generated by the electrical path L1 to be shut off by the fixed iron piece 11 and the moving iron piece 12. Thus, the tripping device 1 according to this embodiment achieves the advantage of making it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate 4. Consequently, this achieves the advantage of allowing the bimetal plate 4 to detect any abnormal electrical conditions more accurately.
[0071] In addition, interposing the bimetal plate 4 between the fixed iron piece 11 and the moving iron piece 12 causes, when the current value of electricity being supplied from an external power supply to a load becomes higher than a threshold value, a magnetic circuit passing through the bimetal plate 4 and the fixed iron piece 11 to be further formed, thus magnetizing the bimetal plate 4. Consequently, attraction force (magnetic force) with which the bimetal plate 4 attracts the moving iron piece 12 is generated. Thus, this achieves the advantage of allowing, when the current value of electricity being supplied from the external power supply to the load becomes higher than the threshold value, the bimetal plate 4 to attract the moving iron piece 12 with stronger force.
[0072] In the tripping device 1 according to this embodiment, the fixed iron piece 11 has the first surface X1 and the moving iron piece 12 has the second surface X2 facing the first surface X1. The bimetal plate 4 and the electrical path L1 are arranged between the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12. This allows the heat generated by the electrical path L1 to be shut off more smoothly by the fixed iron piece 11 and the moving iron piece 12. Consequently, the tripping device 1 according to this embodiment achieves the advantage of making it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate 4.
[0073] In the tripping device 1 according to this embodiment, the bimetal plate 4 and the electrical path L1 are arranged parallel to the first surface X1 of the fixed iron piece 11. This makes the clearance between the bimetal plate 4 and the part, located between the first surface X1 of the fixed iron piece 11 and the second surface X2 of the moving iron piece 12, of the electrical path L1 uniform. This achieves the advantage of making the heat generated by the electrical path L1 transferrable more smoothly to the bimetal plate 4.
[0074] In the tripping device 1 according to this embodiment, the fixed iron piece 11 includes the first part 111, the second part 112, and the third part 113. The first part 111 has the shape of a flat plate having the first surface X1, the first end 1111, and the second end 1112. The second part 112 protrudes along the thickness of the first part 111 from the first end 1111 of the first part 111. The third part 113 protrudes along the thickness of the first part 111 from the second end 1112 of the first part 111. The bimetal plate 4 is interposed between the second part 112 and third part 113 of the fixed iron piece 11. This allows the heat generated by the electrical path L1 to be shut off even more smoothly by the second part 112 and third part 113 of the fixed iron piece 11. Consequently, the tripping device 1 according to this embodiment achieves the advantage of making it even easier to ensure a temperature high enough to trip the indirectly heated bimetal plate 4
[0075] In the tripping device 1 according to this embodiment, the first gap Y1 is left between the bimetal plate 4 and the electrical path L1. This achieves the advantage of making it easier to deform, when the heat generated by the electrical path L1 is transferred to the bimetal plate 4, the bimetal plate 4 to have its tip 42 bent and displaced backward. That is to say, this configuration achieves the advantage of making the bimetal plate 4 deformable more smoothly.
[0076] In the tripping device 1 according to this embodiment, the bimetal plate 4 has the shape of a flat plate having the connection end 41 and the tip 42. The connection end 41 is connected to the electrical path L1 and the first gap Y1 is left between the tip 42 of the bimetal plate 4 and the electrical path L1. This achieves the advantage of making it easier to deform, when the heat generated by the electrical path L1 is transferred to the bimetal plate 4, the bimetal plate 4 to have its tip 42 bent around the connection end 41 and displaced backward. That is to say, this achieves the advantage of making the bimetal plate 4 deformable more smoothly.
[0077] In the tripping device 1 according to this embodiment, the electrical path L1 is interposed between the bimetal plate 4 and a part (i.e., the first part 111) of the fixed iron piece 11, and the second gap Y2 is left between the electrical path L1 and the fixed iron piece 11. This achieves the advantage of allowing the heat generated by the electrical path L1 to be transferred to the fixed iron piece 11 less easily.
[0078] (4) Variations
Note that the embodiment described above is only an exemplary one of various embodiments of the present disclosure and should not be construed as limiting. Rather, the exemplary embodiment may be readily modified in various manners depending on a design choice or any other factor without departing from the scope of the present disclosure. Note that the variations to be described below may be adopted in combination as appropriate.
[0079] In the embodiment described above, the push-in portion 14 is made of a material lighter than that of the moving iron piece 12. Alternatively, the push-in portion 14 may also be made of a magnetic material. For example, the push-in portion 14 may be made of the same material as the moving iron piece 12 that is made of a magnetic material. Note that if the push-in portion 14 is formed integrally with the holder 13, then the holder 13 and the push-in portion 14 may be made of a magnetic material. Still alternatively, the push-in portion 14 may also be made of a magnetic material lighter than that of the moving iron piece 12. This configuration achieves the advantage of reducing the magnetic resistance of the moving iron piece 12 and thereby allowing the fixed iron piece 11 to attract the moving iron piece 12 with stronger force.
[0080] In the embodiment described above, the two terminal portions 7 are both screw terminals. However, this is only an example and should not be construed as limiting. Alternatively, at least one of the two terminal portions 7 may also be a terminal portion having a so-called “quick connection structure” which may be connected without screws.
[0081] (Recapitulation)
A tripping device (1) according to a first aspect is configured to open a contact portion (2) by displacing a latch portion (3) from a latched position to a non-latched position when abnormal conditions occur to electricity being supplied from an external power supply to a load via the contact portion (2). The tripping device (1) according to the first aspect includes a fixed iron piece (11), a moving iron piece (12), a push-in portion (14), an electrical path (L1), and an indirectly heated bimetal plate (4). The moving iron piece (12) is configured to move toward the fixed iron piece (11) when the abnormal conditions occur. The push-in portion (14) pushes in the latch portion (3) from the latched position to the non-latched position synchronously with movement of the moving iron piece (12) toward the fixed iron piece (11). The electrical path (L1) is interposed between a part of the fixed iron piece (11) and the moving iron piece (12) to supply the electricity. The bimetal plate (4) is configured to, when deformed under heat generated by the electrical path (L1), displace the push-in portion (14) to the point of pushing in the latch portion (3) from the latched position toward the non-latched position. The bimetal plate (4) is interposed between the part of the fixed iron piece (11) and the moving iron piece (12).
[0082] This aspect achieves the advantage of making it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate (4).
[0083] In a tripping device (1) according to a second aspect, which may be implemented in conjunction with the first aspect, the fixed iron piece (11) has a first surface (X1). The moving iron piece (12) has a second surface (X2) facing the first surface (X1). The bimetal plate (4) and the electrical path (L1) are interposed between the first surface (X1) and the second surface (X2).
[0084] This aspect achieves the advantage of making it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate (4).
[0085] In a tripping device (1) according to a third aspect, which may be implemented in conjunction with the second aspect, the bimetal plate (4) and the electrical path (L1) are arranged parallel to the first surface (X1).
[0086] This aspect achieves the advantage of allowing the heat generated by the electrical path (L1) to be transferred to the bimetal plate (4) more smoothly.
[0087] In a tripping device (1) according to a fourth aspect, which may be implemented in conjunction with the second or third aspect, the fixed iron piece (11) includes a first part (111), a second part (112), and a third part (113). The first part (111) has the shape of a flat plate having the first surface (X1), a first end (1111), and a second end (1112). The second part (112) protrudes from the first end (1111) along the thickness of the first part (111). The third part (113) protrudes from the second end (1112) along the thickness. The bimetal plate (4) is interposed between the second part (112) and the third part (113).
[0088] This aspect achieves the advantage of making it even easier to ensure a temperature high enough to trip the indirectly heated bimetal plate (4).
[0089] In a tripping device (1) according to a fifth aspect, which may be implemented in conjunction with any one of the first to fourth aspects, a gap (Y1) is left between the bimetal plate (4) and the electrical path (L1).
[0090] This aspect achieves the advantage of making the bimetal plate (4) deformable more easily.
[0091] In a tripping device (1) according to a sixth aspect, which may be implemented in conjunction with the fifth aspect, the bimetal plate (4) has the shape of a flat plate having a connection end (41) and a tip (42). The connection end (41) is connected to the electrical path (L1). The gap (Y1) is left between the tip (42) and the electrical path (L1).
[0092] This aspect achieves the advantage of making the bimetal plate (4) deformable even more easily.
[0093] In a tripping device (1) according to a seventh aspect, which may be implemented in conjunction with any one of the first to sixth aspects, the electrical path (L1) is interposed between the bimetal plate (4) and the part of the fixed iron piece (11). A gap (Y2) is left between the electrical path (L1) and the fixed iron piece (11).
[0094] This aspect achieves the advantage of allowing the heat generated by the electrical path (L1) to be transferred to the fixed iron piece (11) less easily.
[0095] A circuit breaker (10) according to an eighth aspect includes the tripping device (1) according to any one of the first to seventh aspects, the contact portion (2), and the latch portion (3). The contact portion (2) is inserted into the electrical path (L1). The latch portion (3) opens the contact portion (2) when pushed in by the push-in portion (14) from the latched position to the non-latched position.
[0096] This aspect achieves the advantage of providing a circuit breaker (10) that makes it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate (4).
[0097] A distribution board (100) according to a ninth aspect includes the circuit breaker (10) according to the eighth aspect and a cabinet (93) housing the circuit breaker (10) inside.
[0098] This aspect achieves the advantage of providing a distribution board (100) that makes it easier to ensure a temperature high enough to trip the indirectly heated bimetal plate (4).

Reference Signs List
[0099] 100 Distribution Board
10 Circuit Breaker
1 Tripping Device
11 Fixed Iron Piece
111 First Part
1111 First End
1112 Second End
112 Second Part
113 Third Part
12 Moving Iron Piece
14 Push-In Portion
2 Contact Portion
3 Latch Portion
4 Bimetal Plate
41 Connection End
42 Tip
93 Cabinet
L1 Electrical Path
X1 First Surface
X2 Second Surface
Y1 First Gap (Gap)
Y2 Second Gap (Gap)
, Claims:
1. A tripping device (1) configured to open a contact portion (2) by displacing a latch portion (3) from a latched position to a non-latched position when abnormal conditions occur to electricity being supplied from an external power supply to a load via the contact portion (2), the tripping device (1) comprising:
a fixed iron piece (11);
a moving iron piece (12) configured to move toward the fixed iron piece (11) when the abnormal conditions occur;
a push-in portion (14) configured to push in the latch portion (3) from the latched position to the non-latched position synchronously with movement of the moving iron piece (12) toward the fixed iron piece (11);
an electrical path (L1) interposed between a part of the fixed iron piece (11) and the moving iron piece (12) to supply the electricity; and
a bimetal plate (4) configured to, when deformed under heat generated by the electrical path (L1), displace the push-in portion (14) to the point of pushing in the latch portion (3) from the latched position toward the non-latched position, the bimetal plate (4) being an indirectly heated type and interposed between the part of the fixed iron piece (11) and the moving iron piece (12).

2. The tripping device (1) of claim 1, wherein
the fixed iron piece (11) has a first surface (X1),
the moving iron piece (12) has a second surface (X2) facing the first surface (X1), and
the bimetal plate (4) and the electrical path (L1) are interposed between the first surface (X1) and the second surface (X2).

3. The tripping device (1) of claim 2, wherein
the bimetal plate (4) and the electrical path (L1) are arranged parallel to the first surface (X1).

4. The tripping device (1) of claim 2 or 3, wherein
the fixed iron piece (11) includes:
a first part (111) having a shape of a flat plate, the flat plate having the first surface (X1), a first end (1111), and a second end (1112);
a second part (112) protruding from the first end (1111) along thickness of the first part (111); and
a third part (113) protruding from the second end (1112) along the thickness, and
the bimetal plate (4) is interposed between the second part (112) and the third part (113).

5. The tripping device (1) of any one of claims 1 to 4, wherein
a gap (Y1) is left between the bimetal plate (4) and the electrical path (L1).

6. The tripping device (1) of claim 5, wherein
the bimetal plate (4) has a shape of a flat plate having a connection end (41) and a tip (42),
the connection end (41) is connected to the electrical path (L1), and
the gap (Y1) is left between the tip (42) and the electrical path (L1).

7. The tripping device (1) of any one of claims 1 to 6, wherein
the electrical path (L1) is interposed between the bimetal plate (4) and the part of the fixed iron piece (11), and
a gap (Y2) is left between the electrical path (L1) and the fixed iron piece (11).

8. A circuit breaker (10) comprising:
the tripping device (1) of any one of claims 1 to 7;
the contact portion (2) inserted into the electrical path (L1); and
the latch portion (3) configured to open the contact portion (2) when pushed in by the push-in portion (14) from the latched position to the non-latched position.

9. A distribution board (100) comprising:
the circuit breaker (10) of claim 8; and
a cabinet (93) housing the circuit breaker (10) inside.