JP2020021743A - Circuit breaker with terminal temperature display function - Google Patents

Abstract

To provide a circuit breaker with terminal temperature display function, which does not require significant remodeling of circuit breaker, and is hard to be affected by arc gas when the circuit breaker is turned off.MEANS FOR SOLVING THE PROBLEM: In a circuit breaker including a terminal temperature display function for displaying the temperature of the terminal of the circuit breaker, the terminal includes a thermal element formed to extend outward of the circuit breaker, and having one end fixed to the extension of the terminal and the other end disposed to displace freely in response to change of heat. An enclosure for housing the extension of the terminal, the thermal element, a displacement transmission part to which displacement of the thermal element is transmitted and which reciprocates corresponding to response, and a display mechanism which is driven by displacement transmitted from the displacement transmission part, is placed closely to the terminal integrally therewith.SELECTED DRAWING: Figure 1

Description

The present invention detects the temperature of the terminal of a circuit breaker to prevent burnout of a connected electric wire or circuit breaker and spread of fire to building materials and peripheral devices around the circuit breaker. The present invention relates to an intended circuit breaker with a terminal temperature display function.

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

In the circuit breaker, terminals are provided at terminal portions of respective poles in order to electrically connect to electric wires and load devices. Circuit breakers built into distribution boards such as distribution boards and control panels for houses draw wires at construction sites, crimp the wires with crimp terminals, and crimp terminals with the terminal screws. Connected to terminals with screws. At this time, if the screw connection between the crimp terminal and the terminal of the circuit breaker is insufficient, abnormal overheating may occur in the terminal during use of the circuit breaker.

In addition, even during use for many years, repeated expansion and contraction due to ambient vibrations and temperature changes may cause the terminal screws attached to the terminals to become loose. If the screws are not retightened, abnormal overheating may occur due to loosening of the screws.

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

In addition, abnormal overheating 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, or an increase in contact resistance due to pinching of foreign matter.

If such an abnormal overheating state continues, components constituting the circuit breaker and the connected electric wires may be ignited, and there is a concern that fire may spread to building materials and peripheral devices around the circuit breaker.

However, ordinary circuit breakers do not have the function of detecting abnormal overheating of these terminals. In general, in order to prevent abnormal overheating of the terminals, measures are taken to check the connection at the time of construction and perform periodic maintenance and inspections (such as retightening the terminal screws). Although these precautionary measures are effective in preventing abnormal overheating, they cannot be noticed until the next maintenance inspection, so it is impossible to completely prevent burnout and fire spread accidents due to long-term use. Can not.

Therefore, a circuit breaker equipped with an overheat prevention device equipped with a function that detects abnormal overheating of the terminals and shuts off power supply to the load side when abnormal overheating occurs, thereby preventing a burnout accident caused by abnormal overheating A vessel is disclosed. (Patent Document 1, Patent Document 2, Patent Document 3)

Patent Document 1 discloses the following as a device for detecting abnormal overheating. Bimetal plates 25 and 26 for detecting overheating are fixed to the power supply side terminal and the load side terminal of the circuit breaker, respectively, and a transmission plate displaced following the displacement of the bimetal plate is suspended between the two bimetal plates. And, it is always locked to the transmission plate, but at the time of overheating, the displacement of the transmission plate releases the locking relationship with the transmission plate, thereby moving the operation rod to trip the circuit breaker. It is provided. Further, when the locking relationship between the transmission plate and the operating rod is released and the operating rod operates, the operation indicator is displayed by projecting the operating rod outside the circuit breaker, and the operating rod is pressed. And an overheat prevention device which enables resetting of the circuit breaker by adding to a general circuit breaker.

Patent Document 2 is made in view of the mechanical structure in Patent Document 1 described above, and electrically detects abnormal overheating and shuts off by an electric signal output when the abnormal overheating is detected. A device for driving a trip device that opens a contact of a vessel is disclosed.

More specifically, the mechanical operation disclosed in Patent Literature 1 has been made in view of the fact that it often cannot be applied unless the internal mechanism of the circuit breaker is changed. In addition to the above, it is an object of the present invention to centrally manage a circuit breaker in a power supply system or to use the circuit breaker for overheating protection of another device such as an electromagnetic switch provided in the same circuit.

As a configuration for detecting abnormal overheating, a temperature-sensitive element whose electrical output changes in accordance with the temperature of the wire connection terminal, and comparing the electrical output of the temperature-sensitive element with a normal level to detect abnormal overheating. A determination circuit.

Examples of the temperature-sensitive element include a thermistor, a thermocouple using thermoelectromotive force, and an infrared sensor for detecting radiant heat.As an arrangement of the temperature-sensitive element, the temperature-sensitive element is located near a terminal of a mold case. Forming and embedding, independently of the mold case, constitutes a temperature sensor unit integrated by holding on a resin-molded insulating support, and using the mounting groove of the inter-electrode barrier for the temperature sensor unit Form attached to the mold case, Form the temperature sensor unit into a plate shape so that it can be mounted between the back surface of the mold case and the board surface, Terminal used for insulation of the thermosensitive element terminal part of the breaker The temperature sensing element is embedded in an insulator such as ceramic with high thermal conductivity attached to the cover, inserted into the hole provided in the insulating support of the temperature sensor unit, and extended by a spring. Resiliently held so as to be movable in a direction, such as in the form of contacting the distal end of the insulator is disclosed in breaker terminals.

Patent Document 3 is made in view of the complicated structure of Patent Document 1 and Patent Document 2 described above. A bimetal plate for detecting overheating is fixed to the inside of the body of a conductor constituting a connection terminal portion. When the connection terminal portion is overheated by disposing it in the arc space originally provided in the circuit breaker and disposing an interlocking member that engages with and interlocks with the bimetal for overheating detection inside the body. Discloses that the bimetal works in conjunction with an interlocking member to shut off the circuit breaker, and the bimetal cools the generated arc gas, thereby improving the current breaking performance as compared with the conventional circuit breaker.

Specifically, the technique disclosed in Patent Document 1 cannot be applied unless the internal mechanism of the circuit breaker is changed in many cases, and the technique disclosed in Patent Document 2 disposes electric devices. In doing so, it is necessary to attach a unit equipped with a temperature sensor and a determination circuit to the circuit breaker, which requires additional components and a complicated structure. Both Patent Documents 1 and 2 detect abnormal overheating. It was made in view of the technology to add only the function.In particular, the function to detect overheating can be added by simple remodeling without changing the external shape of the circuit breaker. The object of the present invention is to improve the current interruption performance.

Japanese Utility Model Publication No. 56-25156 JP-A-62-8419 JP 2012-216378 A

As disclosed in Patent Literature 1, Patent Literature 2, and Patent Literature 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 a 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 side of the circuit breaker. In addition, since the circuit breaker is significantly modified, for example, the outer shape of the circuit breaker is greatly changed, there is a problem that the number of steps and the cost are increased.

In addition, in Patent Document 2, when arranging the electrical device, it is necessary to separately provide a unit having a temperature sensor such as a temperature sensing element and a determination circuit and attach the unit to a circuit breaker. Because of the large number of components and the necessity of introducing it as a temperature measurement system, it is complicated to add functions. In addition, since the temperature sensing element is attached after being electrically insulated from the main circuit, there is a problem that the temperature is indirectly sensed and an accurate temperature rise is difficult to catch.

Further, in Patent Literature 3, there is no need for significant remodeling of the circuit breaker, an accurate rise in temperature is captured, and the current breaking performance of the circuit breaker is further improved. However, by disposing the bimetal inside the circuit breaker, the bimetal is exposed to the arc gas every time the breaking operation is performed, and thus there is a problem that the overheating detection performance of the bimetal may be deteriorated quickly.

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

A circuit breaker with a terminal temperature display function according to the present invention is configured to solve the above-described problem, and includes a circuit breaker having a terminal temperature display function of displaying a temperature of a terminal of the circuit breaker, The terminal is formed so as to extend outside the circuit breaker, and one end is fixed to the extension forming portion of the terminal, and the other end is displaceably disposed in response to the change in heat. An extension formed portion of the terminal, the thermodynamic element, a displacement transmission section to which the displacement of the thermodynamic element is transmitted and reciprocally displaced in response to a response, and the displacement transmission section A housing housing a display mechanism in which the displacement of the display is driven is transmitted close to the terminal, and one surface of the housing is arranged to face the circuit breaker,
The housing is provided with a housing screw for fixing a lid for the housing,
The housing screw may be inserted from the bottom surface side of the housing toward the top surface side, and the screw head may be located on the bottom surface side of the housing.

According to this configuration, the thermoelectric element is fixed to the terminal of the circuit breaker, and the display unit moves in conjunction with the displacement of the thermoelectric element due to the heat generation of the terminal, so that the temperature according to the heat generation state of the terminal is reduced. Since the display is configured to be displayed, 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 detect 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 the terminal heat generation state can be detected for a long time. Becomes

Further, the displacement transmitting section may be provided in common to each of the thermal elements so that the maximum displacement in each of the thermal elements is transmitted.

According to this configuration, the temperature according to the heat generation state of the terminal that generates the most heat can be displayed from the plurality of terminals of the circuit breaker. Therefore, when it is desired to grasp the maximum temperature, the display unit is arranged for each terminal. No need. Therefore, a plurality of terminals can be collectively monitored with a small number of parts. Further, information necessary for detecting abnormal overheating of the terminal can be displayed.

Further, the display mechanism includes a first display mechanism in which a displacement in one direction among reciprocal displacements in the displacement transmitting unit is transmitted and driven, and a maximum displacement of the displacement transmitting unit is held, and a displacement in both directions of the reciprocal displacement. And at least one display mechanism of the second display mechanism driven following the above.

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

Further, the housing may include a visual recognition unit for visually recognizing the display mechanism from the outside, and one surface of the housing may be arranged 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. In addition, since the housing is arranged close to the circuit breaker, the heat of the terminals can be efficiently conducted, and the accuracy of the display temperature can be improved.

Further, 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 facing the circuit breaker. It may be constituted as.

According to such a configuration, the reset of the maximum heat generation display unit cannot be easily performed, so that 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 that does not require significant modification of the circuit breaker and is not easily affected by arc gas at the time of breaking.

1 shows a schematic diagram of a circuit breaker with a terminal temperature display function showing an embodiment of the present invention. The schematic diagram of the circuit breaker with a terminal temperature display function which removed the electric wire from FIG. 1 is shown. The circuit breaker with a terminal temperature display function described above is shown. The internal assembly figure of the said circuit breaker with a terminal temperature display function is shown. FIG. 4 shows a cross-sectional view AA (structure of a constantly-heating display section) of FIG. 3. FIG. 4 shows a cross-sectional view BB (a structure of a maximum heat generation display section) of FIG. 3. 1 shows a structure for detecting a terminal connection failure in a conventional example.

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

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

First, the basic structure of the circuit breaker 1 shown in FIG. 1 will be described. In FIG. 1, a circuit breaker 1 includes a circuit breaker case 2 having an outer shell formed of a molded case, and a terminal temperature display function unit 3 also having an outer shell formed of a molded case. The circuit breaker housing 2 includes a base 201 for mounting the internal components of the circuit breaker, and a cover 202 that covers the base 201 and covers the internal components. The circuit breaker housing 2 includes a fixed contact (not shown) integrated with the terminal 12 and a movable contact (not shown) for turning on and off the power path and the load path. Will be arranged. Further, an opening / closing mechanism (not shown) for driving the fixed contact and the movable contact to open and close, and by detecting an abnormal current flowing through the electric circuit, acts on the opening / closing mechanism to perform a trip operation of the opening / closing mechanism. A trip device (not shown) for driving the fixed contact and the movable contact to open is provided.

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

The electric wire 4 is connected to the terminal 12 from the outside. A crimp terminal 41 is attached to the distal end of the electric wire 4 by caulking, and the crimp terminal 41 is screwed and fixed to the terminal 12 by the 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, a 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. FIG.

As shown in FIGS. 2 and 3, the terminal temperature display function unit 3 includes a thermodynamic element 32 fixed to the terminal 12 and an operating body 33 to which the displacement of the thermodynamic element 32 is transmitted and which reciprocates in response to a response. And a display unit 34 driven by the displacement of the actuating body 33 being transmitted in conjunction with the displacement of the thermodynamic element 32, and a housing 35 accommodating the thermodynamic element 32, the actuating body 33, and the display unit 34. It is configured with.

The thermodynamic element 32 fixed to the terminal 12 is made of 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 screwing, but is not limited to screwing, and may be fixed by welding or rivets.

As shown in FIGS. 4 and 5, when the thermodynamic element 32 is displaced by the heat conduction from the terminal 12, the display unit 34 is actuated by the actuating body 33 that rotates in the direction B in response to the displacement of the thermodynamic element 32. It moves to the circuit breaker housing 2 side, that is, the left direction in 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 thermodynamic element 32, the magnitude of the displacement of the thermodynamic element 32, that is, the amount of heat generated at the terminal 12, is visually recognized by visually observing the amount of movement. be able to.

The thermodynamic element 32 is quantitatively displaced in accordance with the amount of heat of the terminal 12 and the display unit 34 is moved via the operating body 33 in accordance with the amount of displacement. The amount and the amount of movement of the display unit 34 are correlated, and the heat generation state of the terminal 12 can be displayed.

With such a configuration, the amount of heat generated by the terminal 12 is moved in conjunction with the displacement of the thermodynamic element 32 fixed to the terminal 12 without the need for a significant modification of the circuit breaker housing 2. By visually checking 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 time. It becomes possible.

3, 4, and 5, the display unit 34 is configured to move via the operating body 33. However, the present invention is not limited to this. For example, the display unit 34 directly contacts the thermal element 32 and moves. It is good also as a structure which performs. Also, the moving direction of the display unit 34 is not limited to the circuit breaker housing 2 side, that is, the left direction in FIGS. 4 and 5, but may be, for example, a direction away from the circuit breaker housing 2, that is, the right side in FIGS. It may be configured to move.

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

With such a configuration, the operating body 33 is interlocked only with the thermodynamic element 32 that is displaced at the highest temperature among the plurality of thermodynamic elements 32 attached to the pole terminals 12 across which the operating body 33 extends. The display unit 34 can be moved by rotating in the direction B shown in FIGS. 4 and 5. Therefore, the heat generation states of the plurality of terminals 12 extending over the operating body 33 can be monitored at a time, and only the heat generation state of the terminal 12 which generates the most heat can be displayed. Thus, 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, can be displayed with a smaller number of parts than when the display unit 34 is arranged for each terminal 12.

Next, the 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. FIG. In FIG. 3, the display unit 34 can be constituted 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 display unit 341 is incorporated in the housing 35 together with the constant heat display spring 3411. One end of the constant heat display spring 3411 is fixed to the housing 35, and the constant heat display unit 341 connects the operating body 33. It is urged to rotate in the A direction. The operating body 33 is always rotated in the direction A by the heat-generating display section 341 and is fixed by abutting on the position regulating section 351 of the housing 35, and is in a state where a certain gap is provided with the thermal element 32.

When the terminal 12 generates heat, the thermal element 32 is displaced, and the operating body 33 is rotated in the direction B. The constant heat display portion 341 is opposed to the constant heat 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 is stopped, the displacement of the thermal element 32 is reduced, and the operating body 33 is rotated in the A direction until the operating body 33 is always in contact with the position regulating portion 251 of the housing 35 by the heat generation display spring 3411. Accordingly, the constant heat display unit 341 moves in the opposite direction to the circuit breaker housing 2, that is, in the right direction in FIG. 4 according to the constant heat display spring 3411.

In FIG. 5, a maximum heat generation display portion 342 for maintaining 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 some of the ribs provided on the maximum heat generation display portion 342 have the maximum size. It is sandwiched between the heat generating leaf spring 3421 with a constant load.

When the terminal 12 generates heat, the thermal element 32 is displaced, and the operating body 33 is rotated in the direction B. The maximum heat display portion 342 causes the maximum heat display plate spring 3421 to withstand a certain pinching load, thereby preventing the circuit breaker housing. It moves to the body 2 side, that is, to the left in FIG.

Further, when the heat generation of the terminal 12 is stopped, the displacement of the thermal element 32 is reduced, and the operating body 33 is rotated in the direction A 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 portion 342 is sandwiched between the maximum heat generation display leaf springs 3421 with a constant load and held at the moved position, it does not move to the initial position.

With such a configuration, as for the heat generation state of the terminal 12, the current heat generation state and the state where the terminal 12 generates the most heat over the past and present can be displayed, and the heat generation state of the terminal 12 can be confirmed in more detail. . In the present invention, the display unit 34 may include only the constant heat generation display unit 341, may include only the maximum heat generation display unit 342, or may include both of them. In order to detect the presence or absence of abnormal heat generation, it is preferable that at least the maximum heat generation display unit 342 is provided.

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

The housing 35 houses and arranges the thermodynamic element 32 and the display unit 34 as shown in FIG. 3, and then attaches a lid for the housing as shown in FIG. Is configured to be inaccessible from the outside.

As shown in FIGS. 2 and 3, the housing 35 has a heat display for preventing the operation of the display unit 34 from the outside and for visually confirming the heat generation state of the terminal 12 according to the amount of movement of the display unit 34. A plate 3521, a window frame 3522 for visually displaying the display unit 34 and the heat generation display plate 3521 are provided, and the heat generation state of the terminal 12 is configured to be easily visible. For example, a part of the surface of the display unit 34 that can be visually recognized from the window frame 3522 is made different in color, and the heat generation display plate 3521 is transparent and characters indicating the temperature of the terminals 12 are described at positions corresponding to the amount of movement of the display unit 34. For example, when the display unit 34 moves, the surface of the display unit 34 having different colors according to the amount of movement appears through the heat generation display plate 3521, so that the temperature of the terminal 12 can be confirmed from the window frame 3522.

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 by an intentional operation other than the thermal element 32, and the heat generation state of the terminal 12. Can be displayed accurately. Further, since the window frame 3522 for allowing the display unit 34 to be visually recognized is provided in the housing 35, the display on the display unit 34 can be visually recognized even when the display unit 34 is housed in the housing 35.

Next, while the circuit breaker 1 is attached to the switchboard, the display of the maximum heat display section 342 cannot be reset, and when the circuit breaker 1 is removed from the switchboard, the display of the maximum heat display section 342 can be reset. The attached circuit breaker will be described with reference to FIGS.

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

As described above, the circuit breaker 1 is connected to the switchboard by providing the screw head of the housing screw 353 on the surface where operation by external contact becomes impossible when the circuit breaker 1 is mounted on the switchboard. In this state, 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 the screw 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 cover for the housing, the position of the maximum heat generation display section 342 can be reset to the initial position. Thereafter, the circuit breaker 1 is attached to the switchboard, and the terminal screw 11 and the electric wire 4 are screwed again, so that the maximum heat generation display section 342 of the terminal temperature display function section 3 can be used again, and the screw of the terminal screw 11 can be used. Abnormal overheating of the terminal 12 due to looseness can be prevented.

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

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

For example, although the display unit 34 is moved in the horizontal direction, a method of moving the surface of the display unit 34 by rotating together with the operating body 33 around the operating body 33 in conjunction with the displacement of the thermal element 32 as an axis. It may be.

DESCRIPTION OF SYMBOLS 1 Circuit breaker 11 Terminal screw 12 Terminal 2 Circuit breaker housing 3 Terminal temperature display function part 32 Thermal element 33 Operating body 34 Display part 341 Constant heat display part 3411 Constant heat display spring 342 Maximum heat display part 3421 Maximum heat display Leaf spring 35 Housing 351 Position regulating portion 3521 Heat generation display plate 3522 Window frame 353 Housing screw 4 Electric wire 41 Crimp terminal

Claims (4)

A circuit breaker having a terminal temperature display function for displaying a terminal temperature,
The terminal is formed so as to extend outside the circuit breaker, and has one end fixed to the extension forming portion of the terminal and the other end displaceably disposed in response to a change in heat. Formed with a moving element,
An extension forming portion of the terminal;
The thermal element;
A displacement transmission unit to which the displacement of the thermal element is transmitted and reciprocated in response to the reaction;
A housing housing a display mechanism in which the displacement of the displacement transmission unit is transmitted and driven is arranged close to the terminal and one surface of the housing is arranged to face the circuit breaker,
The housing is provided with a housing screw for fixing a lid for the housing,
A circuit with a terminal temperature display function, wherein the housing screw is inserted from the bottom surface side of the housing toward the top surface side, and the screw head is located on the bottom surface side of the housing. Circuit breaker. The displacement transmission unit is provided commonly to each of the thermal elements,
2. The circuit breaker with a terminal temperature display function according to claim 1, wherein a maximum displacement of each of said thermal elements is transmitted. The display mechanism includes:
A first display mechanism in which a displacement in one direction among the reciprocating displacements in the displacement transmitting unit is transmitted and driven, and a maximum displacement of the displacement transmitting unit is held,
Of the second display mechanism driven following the reciprocal displacement in both directions,
3. The circuit breaker with a terminal temperature display function according to claim 1, further comprising at least one of the display mechanisms. The housing includes a visual recognition unit that visually recognizes the display mechanism from outside,
4. The circuit breaker with a terminal temperature display function according to claim 1, wherein one surface of the housing is arranged to face the circuit breaker. 5.

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