JPH0810576B2 - Overcurrent protection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an overcurrent protection device, and more particularly to an overcurrent protection device used in place of a fuse for overcurrent protection built into a circuit device.

BACKGROUND ART Conventionally, as this type of overcurrent protection device, Japanese Patent Publication No.
There is an overcurrent switch disclosed in Japanese Patent Publication No. 45505. As shown in FIGS. 17 and 18, the casing 1
It has an operating shaft 5 that projects more freely so that it can move back and forth.
The contacts introduced into the main electric path are closed when is pushed into the casing 1, and the contacts are opened when an overcurrent passes through the main electric path. The contact is a fixed contact fixed to one end of the first terminal plate 21 fixed to the casing 1.
23 and a movable contact 24 fixed to one position of the latch link 31 having an L-shaped cross section. The latch link 31 is swingably coupled to the operating shaft 5 and is movable by a latch spring 27.
It is urged in such a direction that the 24 is separated from the fixed contact 23. Further, the operation shaft 5 is biased by a shaft return spring 57 in a direction projecting from the casing 1. On the other hand, a bimetal plate 41 is electrically and mechanically connected to one end of the second terminal plate 22, and a locking projection 44 is provided on one end of the bimetal plate 41. Therefore, when the operating shaft 5 is pushed in,
One end of the latch link 31 engages with the locking protrusion 44 in a state where the spring force is accumulated in the shaft return spring 57. That is, the main electric path is formed by the route of the first terminal plate 21, the latch link 31, the bimetal plate 41, and the second terminal plate 22. In this state, when an overcurrent is applied to the main circuit, the bimetal plate 41 generates heat to release the engagement between the latch link 31 and the locking projection 44, and the operation shaft 5 is moved by the spring force of the shaft return spring 57. The contacts are opened by the spring force of the latch spring 27 and the shaft return spring 57 while protruding from the casing 1.

By the way, in this overcurrent switch, each component is independent and is assembled by sequentially assembling each component at a predetermined position in the casing 1. However, the assembly work is troublesome, and the adjustment work can be performed only after the assembly into the casing 1, and the small overcurrent switch used in place of the fuse is troublesome to assemble and adjust.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and its main purpose is to mount main components on a frame to perform adjustment work before incorporating the components into a casing. And by forming the casing with a pair of halves and a cap connecting the halves,
An object of the present invention is to provide an overcurrent protection device that facilitates assembly work.

DISCLOSURE OF THE INVENTION (Structure) In the present invention, a contact device into which a main circuit is inserted,
A latch device that holds the contact device in the open state in a latched state in which the force in the direction to open the contact device is accumulated, and a latch device that releases the latched state of the latch device when overcurrent passes through the main circuit and In an overcurrent protection device in which a trip device for opening the contact device is housed in an elongated casing, and an operation button for setting the latch device to a latched state is inserted movably back and forth along the longitudinal direction of the casing. The casing is formed of a pair of elongated halves and a cap fitted to the outer periphery of one end in the longitudinal direction so as to connect the halves in a state where both halves are combined. Is a first terminal plate having a first fixed contact, a frame made of a conductive material having a second fixed contact, and a pair of movable contacts that separates and contacts the fixed contacts. With contacts The latch device is mounted on the frame and has a contact pressure spring that is interposed between a part of the frame and the movable contact and that applies a pressing force toward the fixed contact to the end of the movable contact on the movable contact side. And a latch link made of an insulating material that holds the one end of the movable contact on the opposite side of the movable contact with the contact spring interposed between the latch link and the contact spring. And a latch spring for biasing the latch link in a direction in which the movable contact is separated from the fixed contact by a spring force larger than the spring force. A bimetal plate with a locking portion that engages with the latch link in the accumulated state, and a bimetal plate that is inserted into the main circuit and overcurrent passes through the main circuit to heat the bimetal plate and Release the engaged state When the operation device is pushed into the latching state by pressing the operation button with the movable contact opened from the fixed contact, the movable contact is hooked on the hook portion of the operation button to move the movable contact. A hooking piece is provided to prevent the end of the child on the movable contact side from moving toward the fixed contact, and to release the hooking of the operation button to the hooking part when the pressing of the operation button is released. Disclosed is an overcurrent protection device, a contact device,
By incorporating the main parts of the latch device and trip device into the frame, adjustment work can be performed before incorporating them into the casing, and by constructing the casing with a pair of halves and a cap, the frame is incorporated into the casing. The assembly work is easy.

(Embodiment 1) As shown in FIG. 1, a contact device 2 inserted in a main electric circuit.
And a latch device 3 for holding the contact device 2 in the open state in a latch state in which a force in the direction of opening the contact device 2 is accumulated, and a latch state of the latch device 3 is released when an overcurrent passes through the main circuit. And a tripping device 4 for opening the contact device 2 are housed in an elongated tubular casing 1, and an operating button 5 for setting the latch device 3 in a latched state is provided in the casing 1.
It is inserted so that it can move back and forth along the longitudinal direction of the. In the following description, the direction orthogonal to the cross section in FIG.
The left-right direction and the up-down direction will be described as the left-right direction, the front-back direction, and the up-down direction, respectively, and the paper spine side of FIG. 1 will be described as the left side, and the left side of FIG. 1 will be described as the front side.

As shown in FIG. 2, the casing 1 is formed into a long and slender tubular shape that is long in the front-rear direction by a pair of left and right half-split bodies 11a, 11b and a cap 12 attached to the front ends of the half-split bodies 11a, 11b. The half-divided halves 11a, 11b are formed in a shape in which one of the left and right side surfaces and the front surface are open, and in the pair of upper and lower positioning recesses 13 formed on the side surface of the rear end portion of the one half-divided body 11a. The left and right half halves 11a and 11b are butted against each other with a pair of positioning protrusions (not shown) projectingly provided on the rear end side surface of the half halve 11b. In this manner, the cap 1 is attached to the outer peripheral surface of the front end portion of the half-split bodies 11a and 11b with the front half-split bodies 11a and 11b combined.
2 is fitted. The cap 12 is formed in a tubular shape,
Locking step portion 1 formed on the outer peripheral surface of the front end portion of each half body 11a, 11b
The cap 12 is fitted so that the rear end surface of the cap 12 abuts on the cap 4.
The inner diameter of the front end portion of the cap 12 is a guide cylinder portion 15 that is set smaller than the inner diameter of the cylinder portion that joins the half-faced bodies 11a and 11b. Here, the connecting portion between the half-split bodies 11a and 11b and the cap 12 has a non-circular cross-sectional shape in a plane orthogonal to the front-rear direction, so that the half-split bodies 11a and 11b and the cap 12 do not rotate relative to each other. It has become.

The contact device 2 is inserted into the main electric path as described above, and the main electric paths are respectively attached to the rear end portions of the casing 1 and the rear end portions thereof project from the rear end surface of the casing 1.
A frame 6 made of a conductive material such as a copper alloy for holding the terminal plate 21 and the second terminal plate 22, the contact device 2, the latch device 3, and the trip device 4, the first terminal plate 21 and the frame 6. A movable contactor 25 having a pair of movable contacts 24a, 24b that separates from and contact the fixed contacts 23a, 23b respectively provided on the first and second terminals, and a resistance heater 26 for electrically connecting the second terminal plate 22 and the frame 6 to each other. Is formed by. That is, the main circuit is the first
Terminal plate 21-Movable contact 25-Frame 6-Resistance heater 26-
That is, the second terminal plate 22 is formed. Also,
The contact device 2 that opens and closes this main circuit is the first fixed contact 23a.
A movable terminal 25 having a first terminal plate 21 provided with a frame 6, a frame 6 having a second fixed contact 23b, a pair of movable contacts 24a and 24b that separates and contacts the fixed contacts 23a and 23b, and a movable contact. Biasing the central part of 25 downward, the movable contacts 24a, 24b and the fixed contact 23
and a contact pressure spring 27 for obtaining a contact pressure between a and 23b. The first terminal plate 21 is provided with a holding protrusion 21a at the rear portion, and the portion where the holding protrusion 21a is formed is press-fitted into the holding groove 16 formed at the rear end portion of the casing 1 so that the casing 1 is placed at a fixed position. It is fixed. A first fixed contact 23a is fixed to the upper surface of the front end portion of the first terminal plate 21. Frame 6
As shown in FIG. 2, a vertical piece 61b extends upward from the rear edge of the base piece 61a to which the second fixed contact 23b is fixed, and the rear end portion of the base piece 61a extends from the upper edge of the vertical piece 61b. A horizontal piece 61c extending in parallel to the rear side, and a connecting piece 61d extending upward from the right edge of the horizontal piece 61c is formed.A coupling projection 62 projects from the upper edge of the connecting piece 61d. It is set up. On the other hand, at the front end of the frame 6, a holding piece 61e extends upward from the side edge of the front end of the base piece 61a, and the first spring receiving piece 61f parallel to the base piece 61a extends from the upper edge of the holding knit 61e to the right. The second spring receiving piece 61g is formed so as to extend rightward from the front end of the holding piece 61e extending toward the front side of the base piece 61a. Spring receiving protrusions 63 and 64 are provided on the lower surface of the first spring receiving piece 61f and on the front surface of the second spring receiving piece 61g, respectively. Also,
A bearing hole 65 penetrating in the left-right direction is formed in the holding piece 61e. The second terminal plate 22 is connected to the front end of the connecting piece 61d of the frame 6 so as to be spaced apart from the connecting piece 61d on the left side and extend in parallel.
have a. The movable contact 25 is a pair of left and right movable contacts 24.
a, 24b, the hook piece 25a is extended upward from the rear edge,
The engaging piece 25b is formed in a shape extending upward from the front end edge. A spring receiving protrusion is provided on the upper surface of the center of the movable contact 25.
25c is projected, and both ends of the contact pressure spring 27 are attached to the spring receiving protrusion 25c and the spring receiving protrusion 63 provided on the first spring receiving piece 61f of the frame 6, and the center of the movable contact 25 is attached. The part is urged downward. The connection piece 22a of the second terminal plate 22 and the connection piece 61b of the frame 6 are electrically and mechanically connected to respective terminals of the resistance heater 26, and the second terminal plate 22 and the frame 6 are connected via the resistance heater 26. Are electrically connected.
Here, the resistance heater 26 is arranged along the left-right direction.

The latch device 3 includes a latch link 31 formed of an insulating material such as synthetic resin. The latch link 31 has a locking surface 31a on the upper front surface, and an inclined surface 31b on the upper rear surface that reduces the distance from the engaging surface 31a toward the upper side. In addition, on the right side surface of the latch link 31, a cylindrical tube shaft 31
The protrusion c is provided, and the pressing protrusion 31d is provided so as to be spaced upward from the cylindrical shaft 31c. The front end of the movable contact 25 is loosely fitted between the cylindrical shaft 31c and the pressing projection 31d,
The rear end of 25 can swing up and down. Further, the engaging piece 25b of the movable contact 25 is locked to the front surface of the pressing protrusion 31d. The tip end of the cylinder shaft 31c and the left side surface of the latch link 31 pass through, and the rotary shaft 32 is inserted there.
A latch piece 31e extends from the lower part of the front surface of the latch link 31, and the tip of the latch piece 31e is bent to the right. Bearing hole formed in the frame 6 at the left end of the rotary shaft 32
The flange 32a, which is inserted into the rotary shaft 32 and is provided on the rotary shaft 32, is locked to the right side surface of the holding piece 61e of the frame 6, whereby the rotary shaft 32 is prevented from coming out to the left. The right end of the rotary shaft 32 is inserted into the cylinder shaft 31c of the latch link 31, and rotatably supports the latch link 31 with respect to the frame 6. Axis of rotation
Both ends of 32 are supported by bearing recesses 17 formed on the inner peripheral surfaces of both halves 11a and 11b. A latch spring 33 is mounted between the collar 32a of the rotary shaft 32 and the latch link 31. The latch spring 33 has an L-shaped first engaging portion 33a that is engaged with the upper surface of the latch piece 31e of the latch link 31 at one end, and has a first spring receiving piece of the frame 6 at the other end. It has a second locking portion 33b that is locked to the front edge of 61f and biases the latch link 31 to the forward rotation side. That is, in the state where the lower surface of the movable contact 25 at the front end of the movable contact 25 is in contact with the cylindrical shaft 31c, the pressing protrusion 31d applies a counterclockwise force to the engaging piece 25b. The rear end of the movable contact 25 is urged to move upward with the peripheral surface of the cylindrical shaft 31c as a fulcrum. The spring force of the latch spring 33 is set to be larger than the spring force of the contact pressure spring 27. Thus the latch link
A force acts on the movable contact 25 by the 31 and the latch spring 33 in a direction of separating the fixed contacts 23a, 23b and the movable contacts 24a, 24b from each other. The latch link 31 is made of an insulating material as described above, and is interposed between the holding piece 61e of the frame 6 and the front end of the movable contact 25. Therefore, the front end of the movable contact 25 is a frame. It is insulated against 6. The latch device 3 includes the latch link 31, the trip device 4 for locking the latch link 31 in a latched state in which the spring force is accumulated in the latch spring 33, and the latch link from the state in which the spring force of the latch spring 33 is released. It is composed of an operation button 5 for returning 31 to the latched state.

The trip device 4 has an elongated bimetal plate 41 that is long in the front and rear. Bimetal plate 41 with a frame 6 at the rear end
A coupling hole 42 for integrally coupling the bimetal plate 41 to the frame 6 is formed by inserting and crimping the coupling protrusion 62 of the above, and a locking piece 43 is extended to the left side at the front end portion. . A resistance heater 26 as a heat generating device is in close contact with the lower surface of the rear end portion of the bimetal plate 41, and when the resistance heater 26 heats the bimetal plate 41, the front end portion of the bimetal plate 41 is set to warp upward and curve. ing. Locking piece 43
Has a positional relationship such that the locking surface 31a of the latch link 31 can be locked to the rear edge of the locking piece 43. In the state where the latch link 31 and the bimetal plate 41 are engaged, the spring force of the latch spring 33 is accumulated, and in this state, the rear end of the movable contact 25 moves downward by the spring force of the pressure spring 27, The fixed contacts 23a, 23b are in contact with the movable contacts 24a, 24b.

The operation button 5 is formed of an insulating material such as a synthetic resin into a cylindrical shape whose rear surface is open. A drive piece 51 extends rearward from the upper portion of the rear surface of the operation button 5, and a left side edge of the drive piece 51 is cut out in a rectangular shape to form a position regulation recess 52. Further, the rear surface of the drive piece 51 is formed with a hook portion 53 that is inclined downward as it goes rearward. A latch piece 54, which is shorter than the drive piece 51, extends rearward from the lower portion of the rear surface of the operation button 5. Similar to the drive piece 51, the latch piece 54 and the left side edge are cut out in a rectangular shape to form a latch recess 55. The upper portion of the latch link 31 is inserted into the position regulation recess 52, and the hook portion 53, which is the rear end surface of the drive piece 51, is set so as to be positioned corresponding to the hook piece 25a of the movable contact 25. The front end of the latch piece 31e of the latch link 31 can be inserted into the latch recess 55, and when the latch piece 31e of the latch link 31 and the latch piece 54 of the operation button 5 are engaged with each other, The positional relationship is set so that the front end surface is flush with the front surface of the casing 1. A spring receiving projection 56 is provided in the operation button 5 so as to project rearward, and a spring receiving projection 64 formed on the second spring receiving piece 61g of the frame 6 of the spring receiving projection 56 and a button return spring 57. The operation button 5 is urged forward by the spring force of the button return spring 57. The outer peripheral surface of the front end portion of the operation button 5 is formed in a shape that matches the inner peripheral surface of the guide tube portion 15 formed at the front end portion of the cap 12, and the operation button 5 can be smoothly operated back and forth without being fogged. It is like this. Locking protrusions 58 are provided on the upper surface and the lower surface of the operation button 5, respectively. The guide tube portion 15 at the front end portion of the cap 12 and the rear end portion of the cap 12 formed to have a diameter larger than that of the guide tube portion 15. Locking protrusion on the stepped portion 18 formed between
By locking 58, the amount of protrusion of the operation button 5 toward the front of the casing 1 is restricted.

With the above configuration, the contact device 2 excluding the first terminal plate 21,
The latch device 3 excluding the operation button 5 and the button return spring 57, and the trip device 4 are held by the frame 6.
Therefore, the first terminal plate 21 is mounted on the one half-divided body 11a, and after the frame 6 is installed in the one half-divided body 11a with each member mounted on the frame 6, the operation button 5 and the button are pressed. The assembly is completed by mounting the return spring 57, then connecting the other half body 11b, and finally fitting the cap 12, and the fine parts are mounted in the frame 6 in advance. This makes the work easier. In addition, each part can be adjusted in a state where each part is incorporated in the frame 6 before being incorporated in the casing 1, and the adjustment work becomes easy particularly in a small-sized device. As shown in FIGS. 3 and 4, the half-split body 11a
Positioning ribs 19 are provided on the inner peripheral surface of, and by placing the resistance heater 26 on the positioning ribs 19,
The position is set so that the resistance heater 26 is in close contact with the lower surface of the bimetal plate 41. That is, the resistance heater 26
The distance between the bimetal plate 41 and the bimetal plate 41 is prevented from varying depending on the product, and the operating current for releasing the latched state can be set to a substantially constant value.

(Operation) The operation will be described below. Fixed contacts 23a, 23b and movable contact 2
As shown in FIGS. 5 and 7, the locking surface 31a of the latch link 31 is located at the rear edge of the locking piece 43 of the bimetal plate 41 when the contacts in contact with 4a and 24b are closed. It is in the latched state with abutting, and the latch spring 33 has a latch link.
The spring force that biases 31 toward the forward rotation side is accumulated. In the latched state, the movable contact 25 has the hooking piece 25a with the operation button 5
The position corresponding to the rear of the hook portion 53 of the movable contact 24a, 24b
Is held by the latch link 31 so as to be swingable between the fixed contacts 23a and 23b. That is, in the latched state, the movable contact 25 does not receive the pressing force from the pressing protrusion 25b, so that it is pressed downward by the contact pressure spring 27, and as a result, the movable contacts 24a, 24b and the fixed contacts 23a, 23b come into contact with each other. Of. Here, the contact pressure of the contact point is set only by the spring force of the contact pressure spring and is independent of the spring force of the latch spring 33.Therefore, the force for driving the latch link 31 and the contact pressure of the contact point are Can be set independently, which simplifies the design. In the latched state of the operation button 5, the latch piece 54 meshes with the latch piece 31e of the latch link 31, and the front surface of the operation button 5 and the front surface of the casing 1 are substantially flush with each other while the spring force of the button return spring 57 is accumulated. Is set to. That is, the latched state can be confirmed by the position of the operation button 5. The pressing surface 59, which is the front side surface of the position regulation recess 52 of the operation button 5, is separated from the locking surface 31a of the latch link 31 to the front side.

When an overcurrent flows in the main electric path between the first terminal plate 21 and the second terminal plate 22 in the above-mentioned state, the resistance heater 26 generates heat, the bimetal plate 41 is heated, and the front end portion of the bimetal plate 41 moves upward. Bend to. As a result, the locking surface 31a and the locking piece 4
The engagement state with 3 is released, and the latch force of the latch spring 33 causes the latch link 31 to rotate forward. Since the spring force of the latch spring 33 is set to be larger than the spring force of the contact pressure spring 27,
As shown in FIG. 6, the front end portion of the movable contact 25 is pressed downward by the pressing protrusion 31d in front of the fulcrum with the cylinder shaft 31c of the latch link 31 as the fulcrum, and the movable contact 2 is pressed by this pressing force.
5 The rear end moves upward, and the movable contacts 24a and 24b are fixed contacts.
Separate from 23a and 23b. Here, by inserting the two contacts in series in the main circuit and forming the latch link 31 with an insulating material, the latch link 31 is not inserted into the main circuit and the contact is opened. At latch device 3
Since no arc is generated in the latch device 3, welding or wear of the latch device 3 does not occur. That is, since the latch device 3 is not damaged when the contacts are opened, it can be repeatedly used. Further, when the latch link 31 is rotated forward, the engagement state between the latch piece 31e of the latch link 31 and the latch piece 54 of the operation button 5 is released, and the operation button 5 is pressed by the spring force of the button return spring 57. Project from the front of the. The protrusion amount of the operation button 5 from the front surface of the casing 1 is restricted by the positional relationship between the locking protrusion 58 formed on the operation button 5 and the step portion 18 formed on the inner circumference of the cap 12. In this way, when the contact is opened, the operation button 5 projects from the casing 1, so that the state of the contact can be confirmed by the operation button 5. Here, even when the operation button 5 cannot be projected from the front surface of the casing 1 due to an external force acting on the operation button 5 due to a situation such that the front surface of the operation button 5 is in contact with the wall surface, as described above, Latch link
Since there is a certain amount of gap between the locking surface 31a of 31 and the pressing surface 59 of the operation button 5, the latch link 31 can rotate at an angle corresponding to this gap, and thus the contacts can be opened. You can That is, the latch link 31 has the operation button 5
The contacts can be opened without moving, which is so-called trip-free. When the latch link 31 is released from the engagement state with the bimetal plate 41 and rotated by a certain angle, the front end edge of the latch piece 31e comes into contact with the stopper surface 9 in the casing 1 to stop the rotation. . Further, the fixed contact 23b is provided on the frame 6 so that the frame 6 serves as a conductive path, and the movable contact 25 short-circuits the fixed contact 23a provided on the first terminal plate 21 and the fixed contact 23b provided on the frame 6. Because I am
It is not necessary to connect a connection line to the movable contact 25, and the connection line does not hinder the movement of the movable contact 25.

In order to return the contact from the open state to the closed state, the operation button 5 may be pushed into the casing 1. That is, when the operation button 5 is pushed in, the pressing surface 59 of the operation button 5 presses the locking surface 31a of the latch link 31 to rotate the latch link 31 backward against the spring force of the latch spring 33, and the latch link 31
The bimetal plate 41 is pressed upward by the inclined surface 31b and the bimetal plate 41 is bent upward. Here, when the front surface of the operation button 5 is pushed to a position substantially matching the front surface of the casing 1, the front surface of the engaging piece 25a of the movable contact 25 comes into contact with the hooking portion 53 formed at the rear end of the operation button 5. Contact, movable contact 2
5 is locked by the operation button 5 and cannot move downward. Further, when the operation button 5 is pushed in, as shown in FIG. 8, the locking surface 31a of the latch link 31 causes the locking piece 43 of the bimetal plate 41 to move.
Moves behind the trailing edge. Here, since the front end portion of the bimetal plate 41 is released and inverted by the upward pressing force received from the latch link 31, a “snap” is generated.
And a slight shock is felt on the operation button 5,
It is possible to confirm that it is in the latched state. Since the movable contact 25 restricts the movement of the operation button 5 to the rear, the operation button 5 cannot be moved rearward beyond a predetermined amount (set to about 1.25 mm). When the pressing force on the operation button 5 is released from this state, the locking surface of the latch link 31
31a comes into contact with the rear edge of the locking piece 43 of the bimetal plate 41 to be in the latched state, and the movable contact 25 is released from the state of being bound by the operation button 5 and is moved downward by the spring force of the contact pressure spring 27. As a result, the movable contacts 24a, 24b come into contact with the fixed contacts 23a, 23b and the contacts are closed. As described above, by pushing the operation button 5 rearward of the front surface of the casing 1, the latch link 31 and the bimetal plate 41 can be securely engaged with each other to be in the latched state. Therefore, the contact is closed. Therefore, the contact changes from the open state to the closed state at a constant speed set by the spring force of the contact pressure spring irrespective of the moving speed of the operation button 5, so that fluttering of the contact is prevented and the contact In the closed state, a constant contact pressure is always obtained.

(Example 2) In Example 1, only the contact to be inserted into the main electric path was provided, but the auxiliary contact can be provided as follows. The configuration other than the auxiliary contact is the same as that of the first embodiment, and therefore will be omitted.

As shown in FIGS. 9 to 11, a pair of fixed contact plates 71 is provided on the lower peripheral wall of the casing 1, and a movable contact piece 72 capable of contacting both fixed contact plates 71 is provided on the latch piece 31e of the latch link 31. By being fixed, one end of the fixed contact plate 71 and the movable contact piece 72 form an auxiliary contact. Fixed contact plate
The other end of 71 is exposed on the outer peripheral surface of the casing 1 and can be connected to an external circuit. Here, the movable contact piece 72
Is flexible, and the auxiliary contact can be closed even when the contact of the main electric path is opened without the operation button 5 protruding from the casing 1. Fixed contact plate 71
In the contact portion with the movable contact piece 72, a fixed contact 73 may be provided as shown in FIG. By providing an auxiliary contact that closes when the contact opens,
Even when the open / closed state of the contact cannot be identified by the operation button 5 which is trip-free as described above (when the contact is opened without the operation button 5 protruding from the casing 1), the auxiliary contact If the display means is properly connected to, the open / closed state of the contact can be identified.

To provide the auxiliary contact, the fixed contact plate 71 and the movable contact piece 72
Instead of providing and, as shown in FIG. 13 and FIG. 14, a small switch (so-called micro switch) 74 is fixed to the lower part of the casing 1 and its armature 75 is pressed by the latch piece 31e of the latch link 31. You may

(Example 3) In Example 1, a resistance heater 26 is provided as a heat generating device, and the bimetal plate 41 is heated by the resistance heater 26.
Although an example in which the so-called indirectly heated trip device 4 is provided is shown, in the present embodiment, the bimetal plate 41 itself is used as a heat generating device, and the direct heat type trip device 4 in which the bimetal plate 41 is curved by self-heating is used. An example provided is shown.

That is, instead of connecting the connection piece 22a of the second terminal plate 22 and the connection piece 61d of the frame 6 via the resistance heater 26,
The connecting piece 22a of the second terminal plate 22 and the bimetal plate 41 are connected via the connecting wire 28 which is a braided wire. Since the bimetal plate 41 is electrically and mechanically connected to the frame 6, the connecting line 28 electrically connects the second terminal plate 22 and the frame 6. That is, the main electric path is formed by the route of the first terminal plate 21, the movable contact 25, the frame 6, the bimetal plate 41, the connecting line 28, and the second terminal plate 22. The connecting position of the connecting wire 28 to the bimetal plate 41 is set to a position different from the connecting position to the frame 6 of the bimetal plate 41, so that the bimetal plate 41 can self-heat by the energizing current to the bimetal plate 41. As described above, since the resistance heater 26 is not inserted in the main electric line, a large current can be passed through the main electric line.
This embodiment can be used for high rated current in comparison with the above.

As described above, when an overcurrent is applied to the main electric path between the first terminal plate 21 and the second terminal plate 22, the bimetal plate 41 bends due to self-heating of the bimetal plate 41. Similarly, the contacts are opened. The other configurations and operations are the same as those in the first embodiment, and will be omitted.

[Advantages of the Invention] As described above, the present invention includes a pair of elongated halves of a casing, and one half of the halves in a state where both halves are combined with each other. A first terminal plate having a first fixed contact formed by a cap to be fitted, a frame made of a conductive material having a second fixed contact; A movable contact that has a movable contact and short-circuits both fixed contacts, and a pressing force applied to the fixed contact is applied to the movable contact side end of the movable contact that is interposed between a part of the frame and the movable contact. A latching device is rotatably mounted on a rotating shaft mounted on the frame, and one end of the movable contactor opposite to the movable contact is insulated from the brace by sandwiching the contacting spring. Latch link made of insulating material and pressure contact spring And a latch spring for urging the latch link in a direction to separate the movable contact from the fixed contact with a spring force larger than the spring force of the. And a high metal plate with a locking part that engages with the latch link in the state where the latch link and the bimetal plate are inserted into the main circuit and overheated when passing through the main circuit with an overcurrent. Since it has a heat generating device that releases the engagement state of, the main parts of the contact device, the latch device, and the tripping device are installed in the frame, so that the parts are assembled in the frame before being installed in the casing. The adjustment work can be performed, and the adjustment work becomes easy especially when the size is small. Further, since the parts are assembled to the frame and the casing is composed of the pair of half-divided bodies and the cap, the contact device, the latch device, and the trip device can be handled as one block. This has the advantage that the assembly work can be performed by a simple work of simply holding the frame and holding the blocked parts. In addition, when the movable contact is opened from the fixed contact to the movable contact and the operation button is pressed to engage the latch link with the bimetal plate, the movable contact is moved by being caught by the hook portion of the operation button. Since the end portion on the contact side is prevented from moving toward the fixed contact, and the hook is provided so that the hook on the hook portion of the operation button is released when the pressing of the operation button is released, When the operation button is pressed to set the latch device to the latched state, the hooking piece provided on the movable contact catches on the hooking part of the operation button, and the end of the movable contact on the movable contact side faces the fixed contact. The movable contact of the movable contactor can be held in a state where it does not contact the fixed contact, and when the pressing of the operation button is then released, the hooking piece of the movable contactor will not move. To the hook The hook is released, the movable contact moves toward the fixed contact by the spring force of the contact pressure spring, and the movable contact can be closed by the fixed contact, regardless of the moving speed when pressing the operation button. The contact pressure spring changes from the open state to the closed state at a constant speed set by the spring force, which can prevent fluttering of the contacts and can obtain a constant contact pressure of the contacts.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is an exploded perspective view of the same as above, FIG. 3 is an exploded perspective view of essential parts of the same, and FIG. 4 is a side view of essential parts of the same. FIG. 8 to FIG. 8 are explanatory diagrams of the same operation as above, and FIG. 9 is a sectional view of the essential parts showing Embodiment 2 of the present invention
FIG. 10 is a bottom view of relevant parts of the above, FIG. 11 is an enlarged cross-sectional view of relevant parts of the same, FIG. 12 is a cross-sectional view of relevant parts showing another example of the same, and FIGS. FIG. 15 is a sectional view showing a third embodiment of the present invention, FIG. 16 is an exploded perspective view of the same, FIG. 17 and FIG.
The figure is an operation explanatory view showing a conventional example. 1 is a casing, 2 is a contact device, 3 is a latch device, 4 is a tripping device, 5 is an operation button, 6 is a frame, 11a and 11b are halves, 12 is a cap, 21 is a first terminal plate, 22 is a Second terminal plate, 23a and 23b are fixed contacts, 24a and 24b are movable contacts, 25 is a movable contactor, 26 is a resistance heater, 27 is a contact pressure spring, 31 is a latch link, 32 is a rotating shaft, and 33 is a latch. A spring, 41 is a bimetal plate, 43 is a locking piece, and 52 is a hooking portion.

Claims (1)

[Claims] 1. A contact device to be inserted into a main circuit, a latch device for holding the contact device in a closed state in a latched state in which a force for opening the contact device is accumulated, and an overcurrent passing through the main circuit. The tripping device that releases the latching state of the latching device and opens the contact device by the above force is housed in the elongated casing, and the operation button that sets the latching device to the latching state is the longitudinal direction of the casing. In an overcurrent protection device that is inserted back and forth along the direction, the casing has a pair of elongated halves and one end in the longitudinal direction so that both halves are combined in a state where both halves are combined. The contact device is formed of a cap fitted to the outer circumference of the part, and the contact device includes a first terminal plate having a first fixed contact, a frame made of a conductive material having a second fixed contact, and a space between the fixed contacts. A pair of movable contact A movable contactor that has a point and short-circuits both fixed contacts and a movable contactor end that is interposed between a part of the frame and the movable contactor applies a pressing force toward the fixed contact. The latch device has a contact pressure spring, and the latch device is rotatably mounted on a rotary shaft mounted on the frame, and one end of the movable contact opposite to the movable contact is insulated from the frame with the contact pressure spring interposed therebetween. And a latching spring made of an insulating material and a latching spring for urging the latching link in a direction in which the movable contact is separated from the fixed contact by a spring force larger than the spring force of the contact pressure spring. Is fixed to one part of the frame and has a bimetal plate with a locking part that engages with the latch link in the state where the force is accumulated in the latch spring, and the overcurrent has been inserted into the main circuit and the overcurrent has passed through it. Sometimes heating the bimetal plate And a heating device for releasing the engagement between the latch link and the bimetallic strip,
When the operation button is pressed to the movable contact in a state where the movable contact is opened from the fixed contact to bring the latch device into the latched state, the movable contact is caught by the engaging portion of the operation button and the end of the movable contact on the movable contact side. Is provided with a hooking piece that prevents the operation button from moving toward the fixed contact, and that when the pressing of the operation button is released, the hooking piece is released. apparatus.