JPH0336263B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a circuit breaker that can cut off a circuit when a short circuit occurs or when an excessive current exceeding the rating continues to flow. The present invention relates to a circuit breaker that can reliably protect circuits that include elements that are vulnerable to short-circuit currents.

This type of circuit breaker has a fixed contact having a fixed contact and a movable contact that can be welded to the fixed contact, as disclosed in US Pat. A manual opening/closing mechanism that normally operates to separate the movable contact from the fixed contact and includes a trip mechanism that forcibly separates the movable contact from the fixed contact, and It comprises an electromagnetic device that operates in response to an electric current and attracts an armature connected to the trip mechanism, and an arc extinguishing device disposed near the opening/closing position of the fixed contact and the movable contact.

Normally, the contacts are opened and closed by opening and closing the movable contact with respect to the fixed contact via a manual opening/closing mechanism.On the other hand, in the event of a short circuit or when an excessive current exceeding the rating continues to flow, an electromagnetic device is activated.
The contacts are opened and closed by attracting the armature and separating the movable contact from the fixed contact via a trip mechanism. The arc generated when the contact opens is transferred to an arc extinguishing device where it is split, cooled and extinguished.

However, in a well-known circuit breaker, the short circuit current activates the electromagnetic device and attracts the armature, and then the movable contact is separated from the fixed contact via a trip mechanism and the arc is completely extinguished. was relatively long. Therefore, when the circuit for realizing the interruption includes an element with low voltage resistance, such as a semiconductor element, there is a problem that the semiconductor element or the like is destroyed by the high voltage applied during a short circuit. Therefore, in this type of circuit breaker, especially when the electromagnetic device operates in response to a short circuit current, the movable contact is abruptly separated from the fixed contact to extinguish the arc, greatly improving the current limiting effect. It has been desired to be able to smoothly apply the method to circuits including elements with low voltage resistance.

However, the main purpose of the present invention is to
Significantly shortens the time from when the protective sensor detects a current exceeding a predetermined rated value is activated until the movable contact is separated from the fixed contact and the arc is extinguished, greatly increasing the current limiting effect. To provide improved circuit breakers.

Another object of the present invention is to provide a circuit breaker that minimizes the application of short-circuit voltage to a circuit that achieves breakage in the event of a short circuit, and that can sufficiently protect the circuit even if the circuit includes elements with low withstand voltage. It is on offer.

Another object of the present invention is to actively energize the operation of the trip mechanism when separating the movable contact from the fixed contact via the trip mechanism in response to a short circuit current, for example, in response to a short-circuit current. To provide a circuit breaker that greatly shortens the time it takes for a fixed contact and a movable contact to open.

Other objects and advantages of the invention will become apparent from the following detailed description of the embodiments illustrated in the drawings.

It will be understood, however, that the invention is not limited to these examples only, but includes modifications within the scope of the appended claims.

Referring to the drawing, a protection sensor is installed in the center of the cylinder in order to provide the protection sensor with both the ability to respond immediately to short-circuit currents and the ability to respond with a delayed response to currents exceeding a predetermined rated value. A pair of plungers is provided sandwiching the magnetic head. To explain this in more detail, the protective sensor 10 includes a magnetic yoke 11 having a substantially rectangular cross section and a longitudinal cylinder 12. The cylinder 12 has a lower cylinder body 13 made of a non-magnetic material, preferably brass, with an open upper end, and an upper cylinder body 13 made of a non-magnetic material, preferably plastic, with open ends, and a slightly larger diameter than the lower cylinder body. A cylinder body 14 is provided,
Both cylinder bodies 13, 1 are provided in the opening at the upper end of the lower cylinder body 13 and the opening in the upper cylinder body 14.
A magnetic head 15 is fitted to interconnect the two. In addition, a viscous fluid, preferably silicone oil, is sealed in the lower cylinder body 13, and an oil plunger 16 made of a magnetic material, and usually the oil plunger 16, is sealed in the lower cylinder body 13.
Coil spring 1 that presses toward the inner surface of the lower end of
7 is housed therein, passes through the center of the lower side 18 of the yoke 11, and is fixed to the lower side 18 with a portion protruding downward. Furthermore, an operating plunger 19 made of a magnetic material is installed inside the upper cylinder body 14, and the operating plunger 19 has a head portion 2.
A rod portion 21 having a fixed number 0 is integrally provided, and the rod portion 21 is provided so as to be able to extend upward from the upper end of the mouth axis of the upper cylinder body 14. Further, the tapered upper end of the upper cylinder body 14 is fitted into a circular hole having a lip 23 on the upper side 22 of the yoke 11 and is fixed.

Further, a detection coil 24 is wound around the cylinder 12 substantially over the entire longitudinal direction thereof, and the lead-out ends 25 and 26 of the detection coil 24
One side extends substantially horizontally through one side 27 of the yoke 11 and is connected to a sufficiently flexible lead wire 28, and the other side extends downward from the open side of the yoke 11. It is bent and fixed to the terminal fitting 29 of the circuit breaker. Furthermore, the spring force of a coil spring, which will be described later, is normally applied to the actuating plunger 19 so as to displace it upward, and the upper surface of the actuating plunger 19 is normally placed in contact with the inner surface of the upper end of the upper cylinder body 14. ing.

A frame 31 for supporting a manual opening/closing mechanism including a trip mechanism is integrally provided at the upper end of the side portion 27 of the yoke 11 and extends substantially in the direction in which the upper side portion 22 extends. The frame 31 includes a short frame portion 32 and a long frame portion 33 that extend vertically and parallel to each other. In the short frame portion 32, shaft holes 35 and 36 are formed in the most advanced ear portion 34 and in the upper corner near the rear edge, respectively, and a shaft hole 37 is formed in the vicinity of the rear edge below the shaft hole 36. It is perforated. On the other hand, the long frame part 33 has a shaft hole 39 in an enlarged part 38 provided at a position corresponding to the ear part 34 of the short frame part 32, and corresponds to the shaft holes 36 and 37 of the short frame part 32 near the rear edge. Shaft holes 40 and 41 are drilled at the positions shown in FIG. Further, an inverted L-shaped sliding window 42 is formed in the long frame portion 33 with an arcuate edge 43 on one side, and the tip portion is bent at a substantially right angle. Further, a locking portion 45 is provided at the upper end of the bent portion 44, and a small disk-shaped arc running ear portion 46 extends horizontally from the lower edge.

Cylindrical lower part 4 of handle 47 of manual opening/closing mechanism
8 has a shaft hole 49 bored in its center, and an enlarged portion 51 having a through hole 50 formed in a part of its circumferential surface. The handle 47 has short and long shafts 5 held in shaft holes 35 and 39 of the long frame parts 32 and 33.
2 into the shaft hole 49, the frame 31
is rotatably supported. Further, one leg portion 54 of a U-shaped link pin 53 is inserted into the through hole 50 of the enlarged portion 51, and the free end of the leg portion 54 is connected to an L-shaped sliding window of the long frame portion 33. 42 and is movable along the arcuate edge 43. The other leg side 55 of the link pin 53 is inserted into the shaft holes 61, 62 of the ears 57, 58 provided oppositely to the link arm 56, and its free end is loosely engaged with the sliding window 42, It is disposed movably within the other side.

The link arm 56 itself has an inverted U-shaped base 63 when viewed from the end surface, and the base 63 has an insertion window 64.
is formed. The ear portions 57 and 63 extend vertically and parallel to each other downward from the front end of the base portion 63.
Arm portions 65 and 66 with 58 projecting upward are integrally extended, and the arm portions 65 and 66
Shaft holes 67 and 68 are bored in the tip portions of the shafts, respectively. Further, from the lower edge of one arm part, a kicking tongue part 69 is provided which is bent into an L-shape and slightly inclined upward with respect to the vertical direction, and which is bent into an L-shape from the upper edge. A substantially horizontally extending stop ear 70 is provided. A support shaft 71 is held in the shaft holes 67 and 68 at the tips of both the arm parts 65 and 66, and the support shaft 71 is connected to one end of the detection coil 29 and the lead wire 28.
The movable contact 72 is inserted into the shaft hole 73 of the chevron-shaped movable contact 72 connected through the link arm 56, thereby pivotally supporting the movable contact 72 with respect to the link arm 56. A locking hole 74 is provided above the shaft hole 73 of the movable contact 72.
An enlarged portion 75 having a diameter of
Moreover, a movable contact 76 preferably made of a highly conductive contact material is fixed to the lower edge of the tip.

The movable contact 76 of the movable contact 72 is arranged so as to be able to come into contact with a fixed contact 78 attached to a fixed contact 77 disposed below the movable contact 72 and preferably made of a highly conductive material. The fixed contact 77 itself has an arc running portion 80 that extends downwardly from one leg of the U-shaped portion 79 on which the fixed contact 78 is fixed and faces the arc running ear portion 46 of the frame 31. L is extended from the other leg of the U-shaped portion 79.
A connecting portion 82 which is bent into a letter shape and is integrated with the terminal fitting 81 is extended.

According to one feature of the present invention, a configuration is adopted in which the operation of the trip mechanism is positively energized to speed up the opening operation of the movable contact. Further, to explain this trip mechanism in detail, a support shaft 83 held in the shaft holes 36 and 40 of the frame 31 has an interlocking arm 8 of the trip mechanism.
4 is pivoted. The interlocking arm is the protection sensor 1
A pair of arm portions 87 and 88 extend perpendicularly and parallel to each other from the front end of the base portion 86. The support shaft 83 is inserted through the shaft holes 89 and 90 drilled in the frame 31, and the interlocking arm 84 is pivotally supported on the frame 31 as described above. Further, one arm portion 87 has a kicking leg portion 9 which is bent into an L-shape and extends downward, and is capable of striking the kicking tongue portion 69 of the link arm 56 when the interlocking arm 84 rotates.
1 is drilled. In addition, the support shaft 83 has the following features when viewed from the side that operates integrally with the interlocking arm 84:
An L-shaped latch fitting 92 is pivoted through shaft holes 93 and 94 so as to be rotatable in a direction away from the link arm when the contact is opened, and one side of the latch fitting 92 is attached to the lower surface of the base 86 of the interlocking arm 84. A foot portion 9 is provided as an abuttable arm portion 95, the other side extends downward, and has a hook portion 96 that protrudes into the insertion window 64 of the link arm 56 and locks on the edge thereof.
It is set as 7.

On the other hand, a coil spring 101 is wound around the support shaft 52 of the handle 47, and the coil spring 101 is guided by a semi-annular guide 47a at the lower part 48 of the handle 47, and one end of the coil spring 101 is connected to the sliding window 42. The other end is locked to the leg side 54 of a U-shaped link pin 53, and the contact is always opened in the direction of opening of the contact with respect to the handle 47, that is, clockwise in FIG. It provides the turning force. Further, the other end of the return spring 102 is engaged with the locking hole 74 of the movable contact 72 in the locking portion 45 at the tip of the long frame portion 33 of the frame 31.
A force is always applied to the movable contact 72 in the direction of separating it from the fixed contact 77. Furthermore, interlocking arm 8
An interlocking arm spring 103 and a latch spring 104 are wound around the support shaft 83 of No. 4.
One end of the interlocking arm spring 103 is attached to the lower surface of the base 86 of the interlocking arm 84, and the other end is attached to the frame 3.
The interlocking arm 84 is always actuated in the counterclockwise direction in FIG. Further, one end of the latch spring 104 is latched to the latching shaft 105, and the other end is latched to a suitable position of the frame 31, for example, to the edge of a round hole 106 in the long frame portion 33, so that the latch fitting 94 is always held as shown in FIG. counterclockwise, i.e. link arm 56
It functions so that it can be locked with.

An arc extinguishing device 110 is disposed between the arc traveling ear portion 46 of the frame 31 and the arm traveling portion 80 of the fixed contact 77.
is installed. The arc extinguisher 110 includes a recess 111 through which the tip of the movable contact 72 can pass, and a number of de-ion grids 112 spaced apart from each other with small gaps. The group of deion grids 112 is held by both side plates 113 and 114, and an end plate 115 fixed to the side plates 113 and 114 is provided at the edge thereof. An arc gas outflow window 116 is formed in the end plate 115, and a direct emission prevention plate portion 117 is provided at the center of the outflow window 116 at a location corresponding to the recess 111 of the deion grid 112.

A casing 120 that houses all the components mentioned above.
The casing halves 121 and 122 are divided into two parts.
A notch is provided to form a rectangular long hole 123 on one end surface on the side where the arc extinguishing device 110 is disposed when the arc extinguishing device 110 is disposed. The long hole 123 is the arc extinguishing device 1
It is located on the back of the direct release prevention plate 117 of No. 10. The casing 120 also has a handle 47.
A handle hole 124 is defined in the upper surface portion of the handle hole 124 to project the handle hole 124 and restrict its rotation within a predetermined rotation angle.
Directly below the handle 47, a lower portion 48 of the handle 47 is rotatably seated. Further, a protrusion 125 is provided inside the casing 120 to abut against the stop ear 70 of the link arm 56 and restrict the rotation range of the link arm 56.
A prismatic portion 126 is provided in a protruding manner to which two U-shaped portions 79 can be combined. Furthermore, pedestals 127 and 128 are expanded within the casing 120 so that the protection sensor 10 and the arc extinguisher 110 can be seated securely, respectively.

Further, the operation of the present invention will be explained. When the handle 47 of the manual opening/closing mechanism is currently rotated clockwise in the position shown in FIG. 2, FIG. 4, or FIG. 14, one leg portion 54 of the link pin 53 is in the sliding window. 42, and the other leg side 55 is located above the other side of the sliding window 42, and the return spring
02 is also applied, and the link arm 56 and the movable contact 72 are moved upward. Therefore, the movable contact 76 of the movable contact 72 is separated from the fixed contact 78 of the fixed contact 77, that is, the contact is in an open state.
In this case, the link arm 56 is prevented from moving upward more than necessary by the protrusion 125 of the casing. On the other hand, from the position shown in Fig. 2, Fig. 4, or Fig. 14,
The coil spring 1 is in the position shown in the figure or FIG. 15, that is, the handle 47 is wound around the handle spindle 52.
01 and the spring force of the return spring 102, the enlarged portion 5 of the lower part of the handle 48
When the position of one leg side 54 of the link pin 53 inserted through the through hole 50 of 1 crosses the line connecting the support shaft 52 of the handle and the other leg side 55 of the link pin 53, the coil spring 101 In addition, the handle 47 overcomes the spring force of the return spring 102.
is stopped and held in the counterclockwise rotation position. As a result, one leg side 54 of the ring pin 53 reaches the lower part of the arcuate edge of the sliding window 42 and the other leg side 55 reaches the lower part of the other side of the sliding window 42, that is, the link pin 53 reaches the lower part of the arcuate edge of the sliding window 42. Since the state is substantially vertical and the hook portion 96 of the latch fitting 92 is engaged with the edge of the insertion window 64 of the link arm 56, the link arm 56 is connected to the link arm 56 via the link arm 56 and the support shaft 71. The connected movable contacts 72 move downward and tilt forward, and the movable contact 76 contacts the fixed contact 78, that is, the contact is in an open state. In this case, the electrical circuit includes the terminal fitting 29, the detection coil 24, and the lead wire 2.
8, movable contact 72, movable contact 76, fixed contact 7
8, a fixed contact 77 and a terminal fitting 81.

Furthermore, if an excessive current, for example, a current 1.15 times the rated current, continues to flow when the contacts shown in FIGS. The oil plunger 16 is energized and the coil spring 1
7 and the magnetic head 15 relatively slowly while resisting the viscosity of the oil sealed in the lower cylinder body 13.
is adsorbed to. This provides a time delay effect and does not respond to an excessive current flowing for a relatively short period of time, such as a starting current, even if it is detected. magnetic head 15
When the oil plunger 16 is attracted to the position shown in FIG. It is attracted to the magnetic head 15 in this way. Along with this, the interlocking arm 84 and the support shaft 8
3, and the latch fitting 92 also rotates around the support shaft 83.
The hook portion 96 of the latch fitting 92 is disengaged from the edge of the locking window 64 of the link arm 56, and the kick leg portion 91 of the interlock arm 84 is rotated about , in the direction away from the link arm 56, as shown in FIG. However, without receiving any spring force applied to the latch fitting 92,
The kicking tongue portion 69 of the link arm 84 is struck. Therefore, this impact strongly applies a so-called starting force to the link arm 56, and also causes the link arm 5 to
The rotational force of link arm 5 is rapidly increased, and
Together with the tensile force of the return spring 102 that is engaged with the movable contactor 72 connected to the 17th
As shown in the figure, the movable contact 72 is rapidly separated from the fixed contact 77. At this time, the arc generated when the contact is opened is driven toward the arc extinguishing device 110 by the electromagnetic driving force generated by the current flowing through the fixed contact 77 or the movable contact 72, and is extinguished. When the movable contactor 72 moves upward, the upper tip of the movable contactor 72 is located very close to the frame 31, and after the contact is opened, the frame 31 having the arm running ear portion 46 and the yoke 11 integrated with the frame 31 An electric path can be formed through the . In addition, arc gas generated during arc extinguishing is removed by arc extinguishing device 1.
The discharge window 116 formed in the end plate 115 of No. 10 can be discharged to the outside through the elongated hole 123 of the casing 120.
in longitudinal alignment with the emission window 116.
Since the direct discharge prevention plate 117 is attached to the arc gas, the arc gas bypasses the direct discharge prevention plate 117 without being directly discharged to the outside.

Furthermore, when the contacts shown in FIGS. 5 and 15 are opened, when a short-circuit current, for example, a current two or three times the rated current flows, the excitation force by the detection coil 24 is extremely large, so as shown in FIG. Actuation plunger 19
The magnetic head 15 immediately begins to be attracted to the magnetic head 15. At this time, the interlocking arm 84 and the latch metal fitting 92 rotate around the support shaft 83, and the latch metal fitting 92 rotates around the support shaft 83.
When the hook portion 96 of the link arm 56 comes off the edge of the locking window 64, the kick leg portion 91 of the interlocking arm 84 hits the kick tongue portion 69 of the link arm 84 as described above with reference to FIG. Therefore, as described above, this impact imparts a so-called strong starting force to the link arm 56, and the movable contact 72 is rapidly separated from the fixed contact 77 as shown in FIG. Other actions are the same as when excessive current is detected.

In the circuit breaker according to the above-described embodiment, the protective sensor 10 operates relatively slowly at an overcurrent of up to twice the rated current, as shown by curve X in FIG. It has been found that at currents that exceed the width, the contact can be opened in 1.01 seconds or less, and furthermore, at large currents that exceed 10 times the rated current, the contacts can be opened in a time closer to 0.001 seconds than 0.01 seconds, that is, instantaneously. are doing. On the other hand, with conventional protective sensors that have a time delay effect, it usually takes more than one second for the contact to open even if a short circuit current of about three times the rated current flows, as shown by A, and for example, due to magnetic characteristics etc. Even with conventional protection sensors that have a time-delaying effect that improves speed and speeds up the process, it takes nearly one second for the contact to open at a short-circuit current that is more than three times the rated current. Therefore, this method cannot be applied when the circuit for realizing the cut-off includes an element with low voltage resistance such as a semiconductor element. On the other hand, conventional protection sensors that focus only on immediate action do not have a time delay effect, so they will operate even if a current of 1.25 times the rated current or less flows for about 0.1 seconds, and there is a risk that they will react even with starting power, for example. In addition to lacking in versatility, it still required about 0.01 seconds to operate even at a current exceeding 10 times the rated current, and was still inferior in terms of quickness.

In addition, in the circuit breaker according to the above-described embodiment, the responsiveness is greatly improved by striking the link arm when the protection sensor is activated, and the peak value of the arc voltage can be brought about in an extremely quick time. Significantly improves current limiting effect. Therefore, the arc extinguishing time when the arc extinguishing device is not provided is substantially 10 seconds as shown in curve a shown in FIG. 19, and the arc extinguishing time when the arc extinguishing device is provided is as shown in curve b. When the present invention is applied to a conventional circuit breaker with a time of approximately 6 seconds, the arc extinguishing time is substantially 4 seconds.
It has been found that this can be achieved in about seconds.

According to the circuit breaker of the present invention configured as described above, the protective sensor has a time delay effect, has sufficient immediate action function, and has a remarkable shortening of the opening operation time of the movable contact with respect to the fixed contact. Since it can be shortened to
Since it can be applied to a wide variety of circuits and generally achieves a high degree of current limiting effect, it can also be applied to circuits that include elements with low withstand voltage, providing extremely high versatility.

[Brief explanation of drawings]

Fig. 1 is a plan view of a circuit breaker according to the present invention, Fig. 2 is a side view of the circuit breaker of Fig. 1 with half of the casing made up of two parts removed, and Fig. 3 is a circuit breaker of the same type. Figure 4 is an exploded perspective view showing the components of the device excluding the casing, and Figure 4 is the same as Figure 1.
5 is a sectional view showing only the main components of FIG. 4 when the contacts are closed, FIG. 6 is a sectional view taken along the - line in FIG. 2, and FIG. is a sectional view taken along the - line in Fig. 2, Fig. 8 is a sectional view taken along the - line in Fig. 2, Fig. 9 is an end view of the same circuit breaker, and Fig.
The figure is a cross-sectional view similar to Figure 5 when an excessive current flows through the detection coil of the above circuit breaker, and Figure 11 is a cross-sectional view when the protection sensor of the above circuit breaker is fully activated due to excessive current. A cross-sectional view similar to FIG.
Figure 12 is a cross-sectional view similar to Figure 5, showing a process of operation of the protective sensor and manual opening/closing mechanism when short-circuit current flows through the detection coil of the circuit breaker, and Figure 13 is 14 is a cross-sectional view similar to FIG. 5 when the protective sensor of the above circuit breaker is fully activated, and FIG. 14 is a line diagram in the same state as FIG. , 1st
Fig. 5 is a diagram similar to Fig. 14 in the same state as Fig. 5, and Fig. 16 is a diagram showing a process of operation when an excessive current flows through the detection coil of the same circuit breaker.
Figure 17 is a diagram similar to Figure 4, the same state as Figure 11, and Figure 14 is a diagram similar to Figure 14, Figure 18 is the relationship between current flowing to the protective sensor and operating time in the same circuit breaker. FIG. 19 is a diagram showing the arc-extinguishing characteristics of the above circuit breaker in comparison with a conventional product. 10...Protection sensor, 11...Yoke, 12...
...Cylinder, 13...Lower cylinder body, 14...
Upper cylinder body, 15... Magnetic head, 16...
Oil plunger, 17...Coil spring,
18... Lower side part, 19... Operating plunger, 20
...head part, 21 ... rod part, 22 ... upper side part, 23 ... lip part, 24 ... detection coil, 2
5, 26... Pull-out end, 27... Side part, 28...
Lead wire, 29...Terminal fitting, 31...Frame, 32...Short frame part, 33...Long frame part, 34...Ear part, 35, 36, 37...Shaft hole,
38... Ampulla, 39, 40, 41... Shaft hole, 4
2... Sliding window, 43... Arc-shaped edge, 44... Bent part, 45... Locking part, 46... Arc traveling ear part,
47... Handle, 48... Lower part, 49... Shaft hole, 50... Through hole, 51... Ampulla, 52... Support shaft, 53... Link pin, 54, 55... Leg side part, 56 ... Link arm, 57, 58 ... Ear part, 61, 62 ... Shaft hole, 63 ... Base, 64 ...
...Intrusion window, 65, 66...Arm part, 67, 68
...Shaft hole, 69...Kicking tongue, 70...Stop ear, 71...Spindle, 72...Movable contact, 73...
...Shaft hole, 74...Latching hole, 75...Ampulla, 76
... Movable contact, 77 ... Fixed contact, 78 ... Fixed contact, 79 ... U-shaped part, 80 ... Arc traveling plate, 81 ... Terminal fitting, 82 ... Connection part, 83 ...
... Support shaft, 84 ... Interlocking arm, 85 ... Notch, 8
6... Base, 87, 88... Arm part, 89, 9
0...Shaft hole, 91...Kicking foot part, 92...Latch fitting, 93, 94...Shaft hole, 95...Arm part,
96... Hook portion, 97... Leg portion, 101... Coil spring, 102... Return spring, 10
3... Interlocking arm spring, 104... Latch spring, 105... Locking shaft, 106... Round hole, 110... Arc extinguishing device, 111... Recess, 11
2...Deaion Grid, 113,114...
Side plate, 115... End plate, 116... Outflow window, 11
7... Direct release suppression plate, 120... Casing, 1
21, 122...Casing half body, 123...Elongated hole, 124...Handle hole, 125...Protrusion, 1
26...Prismatic section, 127, 128...Pedestal section.

Claims (1)

[Claims] 1 A casing, a handle rotatably held on the casing that partially protrudes from the casing, a link member linked to the handle, and a trip mechanism removable from the link member, and a manual opening/closing mechanism that can be operated by the manual opening/closing mechanism; a movable contact having a movable contact that can be swung by the manual opening/closing mechanism; a fixed contact having a fixed contact from which the movable contact of the movable contact is brought into contact with and separated from the movable contact; The trip mechanism is driven by a spring that separates the contact from the fixed contact, an arc extinguisher disposed near the contact point between the fixed contact and the movable contact, and a detection coil that detects overcurrent. The link member of the manual opening/closing mechanism is connected to a movable contact and moves away from and approaches the fixed contact as the movable contact opens and closes with respect to the fixed contact. The trip mechanism includes a link arm that operates and a U-shaped link pin that connects the link arm and the handle and directly transmits the opening/closing operation of the handle to the link arm and the movable contact. A latch member that can be detached from the link arm in response to the action, and a latch member that is movable independently of the latch member and that is capable of pushing the link arm away from the fixed contact in response to the operation of the protection sensor. A circuit breaker comprising an interlocking arm.