JP7008982B2 - Circuit breaker with terminal temperature display function - Google Patents

Description

The present invention detects the temperature of the terminal portion of the circuit breaker to prevent the connected electric wire and the circuit breaker from burning and spreading the fire to the building materials and peripheral devices around the circuit breaker. Related to the intended circuit breaker with terminal temperature display function.

The circuit breaker detects an accidental current such as an overcurrent, a short-circuit current, or an electric leakage current in an electric circuit, and when a predetermined operating condition is met, the circuit breaker operates to cut off the supply of power to the load side.

The idea circuit breaker is provided with terminals at the terminals of each pole in order to make an electrical connection with electric wires and load devices. For circuit breakers built into distribution boards such as residential distribution boards and control boards, electric wires are drawn in at the construction site, the electric wires are caulked at the crimp terminals, and the crimp terminals are connected by crimp terminals to the circuit breakers. It is connected to the terminal by screw tightening. At this time, if the screw tightening connection between the crimp terminal and the terminal of the circuit breaker is insufficient, abnormal overheating may occur in the terminal while using the circuit breaker.

In addition, even during long-term use, repeated expansion and contraction due to ambient vibration and temperature changes may cause the terminal screws attached to the terminals to loosen, resulting in regular maintenance and inspection (terminals). If the screws are not retightened), abnormal overheating may occur due to loosening of the screws.

Abnormal terminal overheating occurs when the contact resistance between the crimp terminal to which the electric wire is attached and the terminal increases due to the loosening of the terminal screw, and a large Joule heat is generated.

In addition, abnormal overheating also occurs due to an increase in contact resistance due to oxidation of the contact surface between the crimp terminal of the electric wire and the terminal of the circuit breaker, and an increase in contact resistance due to the pinching of foreign matter.

If such an abnormally overheated state continues, the parts constituting the circuit breaker and the connected electric wires may ignite, and there is a concern that the fire may spread to the building materials and peripheral devices around the circuit breaker.

However, a normal circuit breaker does not have a function of detecting abnormal overheating of these terminals. Generally, to prevent abnormal overheating of terminals, measures are taken to check connections during construction and perform regular maintenance and inspection (tightening of terminal screws, etc.). Although these preventive measures are effective in preventing abnormal overheating, it is not possible to notice abnormal overheating until the next maintenance and inspection, so it is not possible to completely prevent burnout accidents and fire spread accidents due to long-term use. Can not.

Therefore, by detecting abnormal overheating of the terminal and shutting off the power supply to the load side when abnormal overheating occurs, a circuit breaker with an overheat prevention device equipped with a function to prevent burning accidents due to abnormal overheating is cut off. The vessel is disclosed. (Patent Document 1, Patent Document 2, Patent Document 3)

Patent Document 1 discloses the following as a means of detecting abnormal overheating. Bimetal plates 25 and 26 for overheat detection are fixed to the power supply side terminal and load side terminal of the circuit breaker, respectively, and a transmission plate that displaces according to the displacement of the bimetal plate is suspended between these two bimetal plates. And, although it is always locked to the transmission plate, when it is overheated, the displacement of the transmission plate causes the locking relationship with the transmission plate to be released, so that the actuating rod moves to trip the circuit breaker. To prepare. Further, when the locking relationship between the transmission plate and the operating rod is released and the operating rod operates, the operating rod protrudes to the outside of the circuit breaker to display the operation, and the operating rod is pressed. An overheat prevention device that enables resetting of the circuit breaker is added to a general circuit breaker.

In Patent Document 2, it is made in view of the mechanical structure in Patent Document 1 described above, and abnormal overheating is electrically detected and cut off by an electric signal output by the detection of the abnormal overheating. Disclosed is what drives a tripping device that opens the contacts of the vessel.

Specifically, the mechanical operation disclosed in Patent Document 1 is made in view of the fact that it cannot be applied in many cases without changing the internal mechanism of the circuit breaker, and in particular, the prevention of overheating of the circuit breaker alone. In addition, the problem was that the circuit breakers in the power supply system could be centrally managed and used for overheat protection of other devices such as electromagnetic switches installed in the same circuit.

As a configuration for detecting abnormal overheating, a temperature-sensitive element whose electrical output changes according to the temperature of the wire connection terminal and an abnormal overheating are detected by comparing the electrical output of the temperature-sensitive element with a normal level. It is equipped with a judgment circuit.

Examples of the temperature-sensitive element include a thermista, a thermocouple using thermoelectromotive force, an infrared sensor for detecting radiated heat, and the like. A form of embedding and arranging, a temperature sensor unit is configured by holding it on a resin-molded insulating support independently of the mold case and integrated, and the temperature sensor unit is used by using the groove for mounting the interpolar barrier. A form attached to the mold case, a form in which the temperature sensor unit is formed in a plate shape so that it can be attached by sandwiching it between the back surface and the board surface of the mold case, and a terminal used for insulating the breaker terminal part of the heat sensitive element. A temperature-sensitive element is embedded in an insulator such as ceramic with high thermal conductivity, which is attached to the cover, and inserted into a hole provided in the insulating support of the temperature sensor unit so that it can be moved in the length direction by a spring. Disclosed is a form in which the tip of the insulator is brought into contact with the terminal portion of the breaker while holding it elastically.

In Patent Document 3, in view of the complicated structures in Patent Document 1 and Patent Document 2 described above, a bimetal plate for detecting overheating is fixed to the inside of the body of the conductor constituting the connection terminal portion. When the connection terminal is overheated by arranging it in the arc space originally provided in the circuit breaker and arranging the interlocking member that engages with and interlocks with the bimetal for overheat detection inside the body. Discloses that the bimetal works in conjunction with the interlocking member to cut off the circuit breaker, and the generated arc gas is cooled by the bimetal to improve the current breaking performance as compared with the conventional circuit breaker.

Specifically, in the case of the technique disclosed in Patent Document 1, in many cases, it cannot be applied without changing the internal mechanism of the circuit breaker, and in the case of the technique disclosed in Patent Document 2, an electric device is arranged. In order to do so, it is necessary to attach a unit equipped with a temperature sensor and a determination circuit to the circuit breaker, parts are added, and the structure is complicated, and both Patent Document 1 and Patent Document 2 detect abnormal overheating. It was made in view of the technology that adds only the function, and in particular, the function to detect overheating can be added by simple modification without changing the outer shape of the circuit breaker, and the conventional circuit breaker has. The task was to improve the current cutoff performance.

Jitsukosho 56-25156 Gazette Japanese Unexamined Patent Publication No. 62-8419 Japanese Unexamined Patent Publication No. 2012-216378

As disclosed in Patent Document 1, Patent Document 2, and Patent Document 3, it is possible to add a function of detecting abnormal overheating of a terminal to a normal circuit breaker. However, in Patent Document 1, in order to add the function of detecting abnormal overheating, it is necessary to separately provide a space for arranging a mechanical mechanism for detecting abnormal overheating on the entire back surface side of the circuit breaker. Since the outer shape of the circuit breaker changes drastically and the circuit breaker is significantly remodeled, there are problems such as an increase in man-hours and an increase in cost.

Further, in Patent Document 2, when arranging an electric device, it is necessary to separately provide a unit provided with a temperature sensor such as a temperature sensitive element and a determination circuit, and attach the unit to a circuit breaker. Since there are many parts and it is necessary to introduce it as a temperature measurement system, it is complicated to add functions. Further, since the temperature sensitive element is attached after being electrically insulated from the main circuit, there is a problem that the temperature is indirectly sensed and it is difficult to capture an accurate temperature rise.

Further, in Patent Document 3, it is not necessary to significantly modify the circuit breaker, an accurate temperature rise can be captured, and there is an effect that the current breaking performance of the circuit breaker is further improved. However, by arranging the bimetal on the inner side of the circuit breaker, the bimetal is exposed to the arc gas in each breaking operation, so that there is a problem that the deterioration of the overheat detection performance of the bimetal may be accelerated.

Therefore, the present invention has been made in view of the above problems, and provides a circuit breaker with a terminal temperature display function, which does not require a significant modification of the circuit breaker and is not easily affected by arc gas at the time of breaking. With the goal.

The circuit breaker with a terminal temperature display function according to the present invention is configured to solve the above-mentioned problems, and is a first housing constituting the outer shell of the circuit breaker and an electric wire from the outside of the circuit breaker. A circuit breaker is arranged adjacent to a second housing constituting the outer shell of the terminal temperature display function unit that displays the temperature of the terminal to which the terminal is connected, and the terminal is formed to extend to the outside of the circuit breaker. At the same time, one end is fixed to the extension forming portion of the terminal, and the other end is formed with a thermal element disposed in a displaceable manner in response to the change in heat, and the extension forming portion of the terminal is formed. The thermal element, a displacement transmission unit that transmits the displacement of the thermal element and reciprocates in response to a response, and a display mechanism that is driven by transmitting the displacement of the displacement transmission unit are housed. The second housing is placed close to the terminal so that one surface of the second housing faces the first housing , and the circuit breaker is attached to the mounting bottom surface and the terminal to be mounted on the power distribution board. Place it between the connected wires and
The second housing is provided with a housing screw for fixing the lid for the second housing.
The housing screw is inserted from the bottom surface side of the second housing toward the top surface side, and the screw head is configured to be located on the bottom surface side of the second housing. It is good to do it.

According to this configuration, the thermal element is fixed to the terminal of the circuit breaker, and the display unit moves in conjunction with the displacement of the thermal element due to the heat generation of the terminal, so that the temperature according to the heat generation state of the terminal is set. Since it is configured to display, it is possible to provide a circuit breaker with a terminal temperature display function that can detect the temperature of the terminal with a simple configuration and can grasp abnormal overheating. In addition, since the thermal element is located outside the circuit breaker, deterioration of the thermal element due to arc gas generated when the circuit breaker is interrupted can be suppressed, and it is possible to detect the heat generation state of the terminal for a long period of time. It becomes.

Further, the displacement transmission unit may be configured to be characterized in that the maximum displacement in each thermal element is transmitted by being provided in common with each thermal element.

According to this configuration, it is possible to display the temperature according to the heat generation state of the terminal that generates the most heat from among the multiple terminals of the circuit breaker. Therefore, if you want to know the maximum temperature, arrange a display unit for each terminal. There is no need. Therefore, it is possible to collectively monitor multiple terminals with a small number of parts. In addition, information necessary for detecting abnormal overheating of terminals can be displayed.

Further, the display mechanism is a first display mechanism in which the displacement in one direction of the reciprocating displacement in the displacement transmission unit is transmitted and driven to maintain the maximum displacement of the displacement transmission unit, and the displacement in both directions of the reciprocating displacement. It may be configured to be provided with at least one display mechanism of the second display mechanism driven in accordance with the above.

According to such a configuration, it is possible to confirm the display of the heat generation state of one or both of the temperature corresponding to the current heat generation state of the terminal and the temperature related to the maximum heat generation state of the terminal.

Further, the housing may be configured to include a visual recognition unit for visually recognizing the display mechanism from the outside, and one side of the housing may be arranged so as to face the circuit breaker.

According to such a configuration, the display shown on the display mechanism of the circuit breaker can be visually recognized from the outside. Further, since the housing is arranged close to the circuit breaker, the heat of the terminal can be efficiently conducted and the accuracy of the display temperature can be improved.

Further, it is characterized in that a reset operation unit for resetting the first display mechanism in a state where the maximum displacement of the displacement transmission unit is held is provided on one surface of the housing which is arranged facing the circuit breaker. It may be configured as.

According to such a configuration, since the maximum heat generation display unit cannot be easily reset, the reliability of the display temperature in the first display mechanism can be improved.

As described above, according to the present invention, it is possible to provide a circuit breaker with a terminal temperature display function, which does not require a significant modification of the circuit breaker and is not easily affected by the arc gas at the time of breaking.

A schematic diagram of a circuit breaker with a terminal temperature display function showing an embodiment of the present invention is shown. FIG. 1 shows a schematic diagram of a circuit breaker with a terminal temperature display function excluding electric wires. The circuit breaker with the terminal temperature display function is shown above. The internal assembly drawing of the circuit breaker with the terminal temperature display function is shown. FIG. 3 shows a cross-sectional view AA (structure of a constant heat generation display unit). FIG. 3 shows a cross-sectional view BB (structure of the maximum heat generation display unit). The structure for detecting the connection failure of the terminal in the conventional example is shown.

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of a circuit breaker with a terminal temperature display function according to the present embodiment. FIG. 2 shows a schematic diagram of a circuit breaker with a terminal temperature display function excluding electric wires from FIG. FIG. 3 shows a circuit breaker with a terminal temperature display function. FIG. 4 shows an internal assembly diagram of a circuit breaker with a terminal temperature display function. FIG. 5 shows a cross-sectional view AA of the circuit breaker with a terminal temperature display function shown in FIG. FIG. 6 shows a cross-sectional view BB of the circuit breaker with a terminal temperature display function shown in FIG. FIG. 7 shows a structure for detecting a terminal connection failure in the conventional example.

First, the basic structure of the circuit breaker 1 shown in FIG. 1 will be described. In FIG. 1, the circuit breaker 1 is composed of a circuit breaker housing 2 whose outer shell is a mold case, and a terminal temperature display function unit 3 whose outer shell is also a mold case. The circuit breaker housing 2 includes a base 201 on which the internal parts of the circuit breaker are mounted, and a cover 202 that covers the base 201 and covers the internal parts. The circuit breaker housing 2 has a fixed contact (not shown) integrated with the terminal 12 and a movable contact (not shown) in order to turn on / off the electric circuit on the power supply side and the electric circuit on the load side. Arranged. In addition, the opening / closing mechanism (not shown) that drives the fixed contact and the movable contact to open / close, and the opening / closing mechanism that acts on the opening / closing mechanism by detecting an abnormal current flowing in the electric circuit to pull off the opening / closing mechanism. A tripping device unit (not shown) for opening and driving the fixed contact and the movable contact is provided.

The circuit breaker 1 is provided with a plurality of terminals 12 connected to an external conductor corresponding to the power supply of each pole, and each of them is exposed to the outside. Further, the terminal 12 is configured to connect the circuit breaker housing 2 and the terminal temperature display function unit 3.

An electric wire 4 is connected to the terminal 12 from the outside. A crimp terminal 41 is attached to the tip of the electric wire 4 by caulking, and the crimp terminal 41 is screwed and fixed to the terminal 12 by a terminal screw 11. At this time, the terminal temperature display function unit 3 is located between the bottom surface of the circuit breaker housing 2 and the electric wire 4 connected to the terminal 12.

Next, the configuration of the terminal temperature display function unit 3 having a function of detecting abnormal overheating of the terminal 12 will be described with reference to FIGS. 2, 3, 4, and 5.

As shown in FIGS. 2 and 3, the terminal temperature display function unit 3 is a working body 33 in which the displacement of the thermal element 32 fixed to the terminal 12 is transmitted and the displacement is reciprocated in response to the response. The display unit 34, which is driven by transmitting the displacement of the operating body 33 in conjunction with the displacement of the thermal element 32, and the housing 35 for accommodating the thermal element 32, the operating body 33, and the display unit 34. Be prepared to be configured.

The thermal element 32 fixed to the terminal 12 is configured by using a bimetal that receives heat conduction from the terminal 12 and is quantitatively displaced. In FIG. 3, the thermal element 32 is fixed to the terminal 12 by screw tightening, but it is not limited to screw tightening and may be fixed by welding or rivets.

As shown in FIGS. 4 and 5, when the thermal element 32 is displaced by heat conduction from the terminal 12, the display unit 34 is subjected to the displacement of the thermal element 32 and is rotated in the B direction by the actuator 33. It moves to the left side of the circuit breaker housing 2, that is, to the left of FIGS. 4 and 5. Since the amount of movement of the display unit 34 also changes according to the magnitude of the displacement of the thermal element 32, the magnitude of the displacement of the thermal element 32, that is, the amount of heat generated by the terminal 12 is visually recognized by visually recognizing the amount of movement. be able to.

The thermal element 32 is quantitatively displaced according to the amount of heat of the terminal 12, and the display unit 34 moves via the actuator 33 according to the amount of displacement. Therefore, the calorific value of the terminal 12 and the displacement of the thermal element 32. The amount and the movement amount of the display unit 34 have a good correlation, and the heat generation state of the terminal 12 can be displayed.

With such a configuration, the display unit 34 moves so that the amount of heat generated by the terminal 12 is linked to the displacement of the thermal element 32 fixed to the terminal 12 without the need for major modification of the circuit breaker housing 2. By visually observing the amount, the heat generation state of the terminal 12 can be displayed with a simple configuration. Further, since the thermal element 32 is located outside the circuit breaker housing 2, the thermal element 32 is not deteriorated by the arc gas generated when the circuit breaker is interrupted, and the heat generation state of the terminal 12 is detected for a long period of time. It becomes possible.

Note that, in FIGS. 3, 4, and 5, the display unit 34 is configured to move via the operating body 33, but the present invention is not limited to this, and for example, the display unit 34 moves in direct contact with the thermal element 32. It may be configured to be used. Further, the moving direction of the display unit 34 is not limited to the circuit breaker housing 2 side, that is, the left direction of FIGS. 4 and 5, for example, the direction away from the circuit breaker housing 2, that is, the right side of FIGS. 4 and 5. It may be configured to move.

Next, a terminal temperature display function unit 3 capable of collectively monitoring a plurality of terminals 12 and displaying necessary information will be described with reference to FIGS. 3, 4, and 5. The operating body 33 shown in FIG. 3 is rotatably fixed to the housing 35 so as to extend over the terminals 12 of each pole.

With such a configuration, the operating body 33 is interlocked only with the thermal element 32 that is displaced at the highest temperature among the plurality of thermal elements 32 attached to the terminal 12 of the pole over which the operating body 33 extends. The display unit 34 can be moved by rotating in the B direction shown in FIGS. 4 and 5. Therefore, it is possible to collectively monitor the heat generation state of the plurality of terminals 12 over which the operating body 33 extends, and it is possible to display only the heat generation state of the terminal 12 that generates the most heat. As a result, it is possible to display the heat generation state of the terminal 12 that is generating the most heat, which is information necessary for detecting abnormal heat generation of the terminal 12, with a smaller number of parts than in which the display unit 34 is arranged for each terminal 12.

Next, a terminal temperature display function unit 3 capable of displaying a more detailed heat generation state of the terminal 12 will be described with reference to FIGS. 3, 4, and 5. In FIG. 3, the display unit 34 can be configured by a constant heat generation display unit 341 and a maximum heat generation display unit 342. The constant heat generation display unit 341 displays the current heat generation state of the terminal 12, and the maximum heat generation display unit 342 maintains the display of the maximum heat generation state of the terminal 12.

In FIG. 4, the constant heat generation display unit 341 is incorporated in the housing 35 together with the constant heat generation display spring 3411, one end of the constant heat generation display spring 3411 is fixed to the housing 35, and the constant heat generation display unit 341 sets the operating body 33. It is urged to rotate in the A direction. The actuating body 33 is constantly rotated in the A direction by the heat generation display unit 341 and is fixed by abutting on the position restricting unit 351 of the housing 35, and is in a state where a constant gap is provided with the thermal element 32.

When the terminal 12 generates heat, the thermal element 32 is displaced, the operating body 33 is rotated in the B direction, and the constant heat generation display unit 341 opposes the constant heat generation display spring 3411, that is, the circuit breaker housing 2 side, that is, Move to the left in FIG. Further, when the heat generation of the terminal 12 subsides, the displacement of the thermal element 32 decreases, and the operating body 33 rotates in the A direction until it comes into contact with the position restricting portion 251 of the housing 35 by the constant heat generation display spring 3411. As a result, the constant heat generation display unit 341 moves to the opposite side of the circuit breaker housing 2, that is, to the right in FIG. 4, according to the constant heat generation display spring 3411.

In FIG. 5, the maximum heat generation display unit 342 that maintains the display of the maximum heat generation state of the terminal 12 is incorporated in the housing 35 together with the maximum heat generation display leaf spring 3421, and a part of the ribs provided in the maximum heat generation display unit 342 is the maximum. It is sandwiched between the heat generation display leaf springs 3421 with a constant load.

When the terminal 12 generates heat, the thermal element 32 is displaced, the operating body 33 is rotated in the B direction, and the maximum heat generation display unit 342 resists a constant pinching load of the maximum heat generation display leaf spring 3421 and is a circuit breaker housing. It moves to the side of the body 2, that is, to the left in FIG.

Further, when the heat generation of the terminal 12 subsides, the displacement of the thermal element 32 becomes small, and the operating body 33 is rotated in the A direction by the constant heat generation display spring 3411 until it comes into contact with the position regulating portion 351 of the housing 35. However, since the maximum heat generation display unit 342 is sandwiched by the maximum heat generation display leaf spring 3421 with a constant load and held at the moved position, it does not move to the initial position.

With such a configuration, regarding the heat generation state of the terminal 12, it is possible to display the current heat generation state and the state when the heat is most generated in the past and present, and it is possible to confirm the heat generation state of the terminal 12 in more detail. .. In the present invention, the display unit 34 may be provided with only the constant heat generation display unit 341, only the maximum heat generation display unit 342, or both of them, but the terminal 12 In order to detect the presence or absence of abnormal heat generation, it is preferable to have at least a maximum heat generation display unit 342.

Next, the terminal temperature display function unit 3 that can prevent the display unit 34 from being operated from the outside will be described with reference to FIGS. 2 and 3.

The housing 35 accommodates and arranges the thermal element 32 and the display unit 34 as shown in FIG. 3, and then attaches the housing lid as shown in FIG. 2, whereby the thermal element 32 and the display unit 34 are attached. Is configured to be inaccessible from the outside.

Further, as shown in FIGS. 2 and 3, the housing 35 has a heat generation display for preventing the display unit 34 from being operated from the outside and visually recognizing the heat generation state of the terminal 12 according to the movement amount of the display unit 34. A plate 3521, a display unit 34, and a window frame 3522 for visually recognizing the heat generation display plate 3521 are provided so that the heat generation state of the terminal 12 can be easily visually recognized. For example, a part of the surface of the display unit 34 that can be visually recognized from the window frame 3522 is colored differently, the heat generation display plate 3521 is transparent, and characters indicating the temperature of the terminal 12 are described at positions corresponding to the movement amount of the display unit 34. For example, when the display unit 34 moves, the temperature of the terminal 12 can be confirmed from the window frame 3522 by the surface of the display unit 34 having different colors appearing through the heat generation display plate 3521 according to the amount of movement.

With such a configuration, the thermal element 32 and the display unit 34 cannot be contacted from the outside, so that the display unit 34 does not move due to an intentional operation other than the thermal element 32, and the terminal 12 generates heat. Can be displayed accurately. Further, since the window frame 3522 for visually recognizing the display unit 34 is provided in the housing 35, the display of the display unit 34 can be visually recognized even when the display unit 34 is housed in the housing 35.

Next, the terminal temperature display function that cannot reset the display of the maximum heat generation display unit 342 while the circuit breaker 1 is attached to the switchboard, and can reset the display of the maximum heat generation display unit 342 by removing the circuit breaker 1 from the switchboard. The attached circuit breaker will be described with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the housing 35 of the terminal temperature display mechanism unit 3 is provided with a housing screw 353 for fixing the lid for the housing. The housing screw 353 is inserted from the bottom surface side of the housing 35 toward the top surface side, and the screw head is configured to be located on the bottom surface side of the housing 35. When the circuit breaker 1 having this configuration is attached to the switchboard, the screw head of the housing screw 353 is closed by the switchboard.

In this way, the circuit breaker 1 is connected to the switchboard by providing the screw head of the housing screw 353 on the surface where the circuit breaker 1 cannot be operated by external contact when the circuit breaker 1 is attached to the switchboard. In this state, the structure is such that the lid of the housing 35 cannot be opened.

When the maximum heat generation display unit 342 becomes a display state indicating abnormal overheating of the terminal 12 due to loosening of screws or the like, the electric wire 4 is removed, the circuit breaker 1 is removed from the switchboard, and the housing screw 353 of the housing 35 is loosened. By opening the lid for the housing, the position of the maximum heat generation display unit 342 can be reset to the initial position. After that, by attaching the circuit breaker 1 to the switchboard and tightening the terminal screw 11 and the electric wire 4 again, the maximum heat generation display unit 342 of the terminal temperature display function unit 3 can be used again, and the screw of the terminal screw 11 can be used again. Abnormal overheating of the terminal 12 due to loosening can be prevented.

With such a configuration, the display of the maximum heat generation display unit 342 can be maintained without being reset while the circuit breaker 1 is being used, so that the abnormal overheating of the terminal 12 can be reliably displayed. Moreover, by removing the circuit breaker 1, the display of the maximum heat generation display unit 342 can be reset and the terminal screw 11 and the electric wire 4 are screwed again, so that the maximum heat generation display unit 342 can be used again. It is possible to prevent abnormal overheating of the terminal 12 due to loosening of screws.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, the display unit 34 is moved in the horizontal direction, but the surface of the display unit 34 is moved by rotating with the operating body 33 in conjunction with the displacement of the thermal element 32 with the operating body 33 as an axis. May be.

1 Circuit breaker 11 Terminal screw 12 Terminal 2 Circuit breaker housing 3 Terminal temperature display function unit 32 Thermal element 33 Actuating body 34 Display unit 341 Constant heat generation display unit 3411 Constant heat generation display spring 342 Maximum heat generation display unit 3421 Maximum heat generation display Leaf spring 35 Housing 351 Position regulation part 3521 Heat generation display plate 3522 Window frame 353 Housing screw 4 Wire 41 Crimping terminal

Claims (1)

The first housing that constitutes the outer shell of the circuit breaker,
It is a circuit breaker in which the second housing constituting the outer shell of the terminal temperature display function unit that displays the temperature of the terminal connecting the electric wire from the outside of the circuit breaker is adjacent to the circuit breaker.
The terminal is formed to extend to the outside of the circuit breaker, and one end thereof is fixed to the extension forming portion of the terminal and the other end is displaceably disposed in response to a change in heat. Formed with a moving element,
The extension forming part of the terminal and
With the thermal element
A displacement transmission unit that transmits the displacement of the thermal element and reciprocates in response to the reaction.
The second housing that houses the display mechanism that is driven by transmitting the displacement of the displacement transmission unit is brought close to the terminal, and one surface of the second housing faces the first housing. In addition, the circuit breaker is placed between the mounting bottom surface to be mounted on the switchboard and the electric wire connected to the terminal.
The second housing is provided with a housing screw for fixing the lid for the second housing.
The housing screw is inserted from the bottom surface side of the second housing toward the top surface side, and the screw head is configured to be located on the bottom surface side of the second housing. Circuit breaker with terminal temperature display function.

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