JPH0345500B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit breaker that is interposed between a power source and a load and is capable of cutting off power supply from the power source to the load when an abnormality in the load is detected.

When tripping occurs due to abnormality detection, an arc runs between the movable contact and the fixed contact, but this arc also runs towards the contact breaking mechanism and spring around both contacts, and as shown in Fig. 19, an arc runs between the movable contact and the fixed contact. In this example, it is not easy to insulate the arc between the contacts 8', 10' and the contact breaking mechanism 95', and if the circuit breaker is made smaller, the arc insulation performance will be lowered, and sufficient insulation performance cannot be achieved. In order to achieve this, it was necessary to ensure sufficient space between them, which caused the problem that the circuit breaker would become larger. Further, when an insulator is interposed between both contacts and the contact interrupting mechanism, there is a problem in that as the circuit breaker is made smaller, the operation of the movable contactor having the movable contacts is hindered.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and its purpose is to protect the spring and contact breaking mechanism from arc during tripping operation by using an arc protection plate, and furthermore, the arc protection plate can To provide a circuit breaker which does not normally interfere with the operation of a movable contact because it sometimes moves together with a spring.

The configuration of the present invention will be described below with reference to illustrated embodiments. FIG. 1 shows the external appearance of a circuit breaker according to an embodiment of the present invention. As shown in the figure, the circuit breaker main body 1 has a pair of casings 2 ₁ and 2 ₂ attached with screws or tacks. A handle 4 for opening and closing the circuit is provided protruding from the upper surface of the circuit breaker body 1. Figure 2 shows the state in which the fixture 3 has been removed and one casing 2 ₁ has been removed from the other casing 2 ₂ , and as shown in the figure, both casings 2 ₁ ,
Various parts such as a pair of external connection terminals 5 ₁ and 5 ₂ , a movable contactor 6, and an arc extinguishing device 7 are housed between 2 ₂ . 3 and 4 individually show the parts required for the operation of the circuit breaker, and FIGS. 5 to 8 show the cross-sectional structure of the circuit breaker. In each of the above figures, 8 is a movable contact attached to the tip of the movable contact 6, and is designed to open and close the main circuit by contacting and separating from the fixed contact 10 attached to one terminal plate ₉₁ . It's getting old. A tightening screw 13 is attached to each terminal plate 9 ₁ , 9 ₂ via a washer 11 and a spring washer 12 , thereby forming a pair of external connection terminals 5 ₁ , 5 ₂ . The engaging hole 15a of the bimetal 15 for overcurrent detection is inserted into the protruding piece 14 protruding from the terminal plate ₉₂ , and the protruding piece 1
4 is inserted, and the bimetal 15 is fixed to the terminal plate ₉₂ . One end of the braided wire 16 is welded to the free end side of the bimetal 15, and the other end of the braided wire 16 is welded to the movable contact 6. Movable contact 6
is connected to a movable arm 17, and this movable arm 17 is adapted to be fitted into a bottom opening 18a of a movable frame 18. 19 is handle 4
and a rotating shaft for pivotally supporting the movable arm 17 and the movable frame 18, and the central portion 19a of the rotating shaft 19 is bent into a substantially U-shape so as to fit into the groove 4a in the handle 4. It's getting old. Further, both ends 19b of the rotating shaft 19 are fitted into a U-shaped groove 20 that serves as a fulcrum of the movable arm 17, and are also fitted into a shaft support hole 21 and a U-shaped groove 22 of the movable frame 18. It's becoming like that. 23 is a tension spring for biasing the handle 4 to the on position and the off position. One end of this tension spring 23 is connected to the rotating shaft 1
9, and the other end thereof is engaged with a pin 25 whose both ends are supported in the shaft hole 24 of the movable arm 17. Therefore, as shown in FIGS. 5 and 7, the handle 4 is biased toward the on position or the off position at the point where the tension spring 23 crosses the rotation center P of the rotating shaft 19. . Also, due to the tensile force of the tension spring 23, the movable arm 17, the movable frame 18, and the rotating shaft 1
9 can be integrated into one. A protrusion 26 is formed at one end of the movable frame 18, and the concave groove 4b of the handle 4 can be engaged with the protrusion 26 as shown in FIG. This makes it possible to prevent the handle 4 from popping out in the direction shown by arrow A during the assembly process of the circuit breaker. Next, 27 is a movable contact 6 during trip operation.
The tip 27a of the spring 27 is inserted into the engagement hole 29 provided in the spring seat 31 of the movable frame 18 through the protective plate 28 for arc prevention. It is adapted to be inserted and engaged. The spring 27 is housed in the storage space 30 of both the casings 2 ₁ and 2 ₂ , and the rear end 27 b of the spring 27 comes into contact with the inner bottom surface 30 a of the spring 27 .
The arc protection plate 28 prevents the spring 27 from being melted and damaged by the arc generated when the movable contact 8 of the movable contact 6 separates from the fixed contact ₁₀ of the terminal plate 91. As shown in FIGS. 17 and 18, the arc protection plate 28 includes a front protection plate 28a, a side protection plate 28b, and a shielding part 28.
d, and an arc protection plate 28 for protecting the spring 27 from arc is movable with the expansion and contraction of the spring 27.
It is installed on. The shielding part 28d is shown in FIGS.
As shown in FIGS. 17 and 18, the front protection plate 28a protrudes from the lower end of the front protection plate 28a toward a space between the contacts 8, 10 and the contact cutoff mechanism 95. The arc protection plate 28 is an insulating material such as fiber.
Further, the front protection plate 28a is provided with a fitting hole 28c into which the tip end 27a of the spring 27 is fitted. The front protection plate 28a and the spring seat 31 of the engagement hole 29 of the movable frame 18 are connected to the spring 27
It is formed with a slight inclination to improve contact with the surface. Reference numeral 32 denotes a yoke plate for short-circuit current detection formed of a magnetic material, and lateral protruding pieces 33 protruding from this yoke plate 32 correspond to engagement plates formed on the pair of casings 2 ₁ and 2 ₂ respectively. Matching hole 3
It is designed to be fixed by 4. The center piece 35 of the yoke plate 32 is adapted to be fixed to the terminal plate 9 ₂ , and side pieces 36 forming magnetic coupling paths extend vertically from both sides of the center piece 35 . 37 is a latch plate, and both ends of the pivot pin 39 inserted into the pivot hole 38 are supported by the engagement holes 40 of both the casings 2 ₁ and 2 ₂ .
The latch plate 37 is rotatable. This latch plate 37 is made of a magnetic material, and when an excessive current flows through the bimetal 15, the latch plate 37 is made of a magnetic material.
The magnetic flux generated around the yoke plate 32 flows through the center piece 35 and the side pieces 36 of the yoke plate 32, so that the magnetic attraction pieces 41 of the latch plate 37 are attracted to the side pieces 36. Also, an abutment piece 42 is provided at the upper end of the latch plate 37.
is formed so as to come into contact with the free end side of the bimetal 15. A locking step 44 is formed at the tip of both side pieces 43 of the latch plate 37, and a locking step 45 of the movable frame 17 is formed.
It is coming into contact with the 46 is latch plate 3
This is a torsion spring that presses the contact piece 42 of the latch plate 37 toward the free end side of the bimetal 15, and as shown in FIGS.
The other end contacts the handle 4 when it is in the OFF position, and contacts the casings 2 ₁ and 2 ₂ when it is in the ON position. Depending on the state of the handle 4, the latch plate 3
The force applied to 7 is changed. The torsion spring 46 is pivoted by being fitted into the pivot boss 47 ₁ of the casing 2 ₁ on the one hand, and received by the pivot boss 47 ₂ of the casing 2 ₂ on the other hand. Both casings 2 ₁ and 2 ₂ also have a shaft support hole 48 for supporting both ends 19b of the rotating shaft 19, a hole 49 for fitting the fixture 3, and a hole 49 for exhausting gas generated when the circuit is interrupted. exhaust hole 50a,
50b etc. are provided. Furthermore, 7 is an arc extinguishing device, which is formed by holding arc extinguishing plates 51 made of a plurality of magnetic materials at appropriate intervals with side plates 52 made of an insulating material, and is fixed to the movable contact 8. The arc generated when the contact 10 is opened can be extinguished as quickly as possible. Each arc-extinguishing plate 51 is provided with a notch 51a so that the movable contact 6 can pass therethrough. This notch 51
A substantially V-shaped cut groove 51b is formed at the lower end of a, and gas accumulated around the contact is discharged through the cut groove 51b to a gas retention section 53 formed behind the fixed contact 10. This makes it possible to improve the interrupting performance. There is also an arc extinguishing chamber 54 in which the arc extinguishing device 7 is housed, and a contact breaking mechanism 95 such as a spring 27 and a movable frame 18.
There is a partition wall 5 between the cut-off mechanism section 55 that stores the
6 is formed to prevent the arc from the arc extinguishing chamber 54 from entering the cutoff mechanism section 55.

Next, the operation of this embodiment will be explained with reference to FIGS. 5 to 8. First, FIG. 5 shows a state in which the circuit breaker is turned off, and in this state, the movable contact 8 and the fixed contact 10 are separated. At this time, the movable contactor 6 is urged by the tensile force of the tension spring 23, and is separated to a position where it comes into contact with the opening edge of the bottom opening 18a of the movable frame 18. Further, the handle 4 is similarly biased by the tensile force of the tension spring 23 and is stopped at a position where the groove 4b engages with the protrusion 26. Further, since one end of the torsion spring 46 is pressed by the outer peripheral surface of the handle 4,
The other end of the torsion spring 46 strongly presses the back side of the abutment piece 42 of the latch plate 37. Therefore, the locking portion 45 of the movable frame 18 is the locking step portion 44 of the latch plate 37.
is securely engaged. Further, due to this engagement, the spring 27 for tripping operation remains compressed within the storage space 30. Figure 6 shows the X-
It shows an X-ray cross-sectional view, and if you look at the figure, you can see that
9 and the pin 25 of the movable arm 17.
It can be clearly seen that the two are pulled together by the tension spring 23. Next, FIG. 7 shows a state in which the circuit breaker is turned on. In this state, the movable contact 6 is biased by the tensile force of the tension spring 23, and the movable contact 8 is pressed against the fixed contact 10. It is stopped at the position. Further, the handle 4 is similarly biased by the tensile force of the tension spring 23,
The operating portion of the handle 4 is stopped at a position where it is in contact with the casings 2 ₁ and 2 ₂ . In this way, the direction in which the movable contactor 6 and the operation part of the handle 4 are biased is such that the tension spring 23 is
It is designed to reverse at the point where it crosses the boundary. Therefore, when the circuit breaker is on, the torsion spring 46 as shown in FIG.
Since one end is no longer pressed against the outer peripheral surface of the handle 4, the other end of the torsion spring 46 has a weaker pressing force than in the OFF state, so that the desired force can be applied to the contact piece 42. It's getting old. Therefore, if the bimetal 15 is deformed by an overcurrent and presses against the abutting piece 42, or if the yoke plate 32 is magnetized by a short-circuit current flowing through the bimetal 15 and attracts the magnetic attraction piece 41, the latch will not be activated. The plate 37 is designed to rotate around the pivot pin 39, whereby the locking step portion 44 and the locking portion 45 are disengaged, the spring 27 is expanded, and the movable frame 18 is adapted to rotate about the rotation center P of the rotating shaft 19. FIG. 8 shows a state in which such a tripping operation is performed. As shown in the figure, the movable frame 18 is pressed by the spring 27 and rotates, so that the movable contact 6 touches the bottom surface of the movable frame 18. It is pushed by the opening edge of the opening 18a and is forcibly driven in the contact opening direction. At the same time, the shielding part 28d of the arc protection plate 28 protrudes between the arc extinguishing chamber 54 and the cutoff mechanism part 55 at the same speed as the movable contact 6, and protects the contact cutoff mechanism 95 from the arc. When the movable contact 6 is separated by a predetermined distance, the tension force of the tension spring 23 drives the movable contact further in the contact separation direction, and finally the movable arm 17 comes into contact with the pivot pin 39, and the movable arm 17 When the handle 4 stops, the concave groove 4b is connected to the movable frame 1.
It is adapted to stop at a position where it is engaged with the protruding step portion 26 of No. 8. At this time, since the movable frame 18 is tilted, the operating portion of the handle 4 stops approximately at the center between the on position and the off position, indicating that a trip operation has been performed. When such a tripping operation is performed, the handle 4 is temporarily returned to the OFF position and the locking step 4 is closed, as shown in FIG.
The handle 4 cannot be stopped at the on position unless the engagement between the handle 4 and the locking portion 45 is restored. As is clear from a comparison between FIG. 5 and FIG. 7, the opening width of the bottom opening 18a of the movable frame 18 is longer than the opening/closing stroke of the movable contact 6, so that manual opening/closing is not possible. When the trip operation is not performed as during operation, the movable contactor 6 is moved by the spring 27 or the movable frame 18.
Also, it is not affected by the contact breaking mechanism 95 such as the latch plate 37. Furthermore, in this embodiment, since one end of the torsion spring 46 is separated from the handle 4, the abutment piece 42 of the latch plate 37 is strongly pressed when it is off, so that it is difficult to open and close the handle 4 manually. The locking step portion 44 and the locking portion 4 are separated by vibration.
It is possible to reduce the risk of disengagement with 5.

By the way, when the movable contact 8 and the fixed contact 10 are opened and the main circuit is interrupted, an arc is generated between the movable contact 8 and the fixed contact 10, but this arc is caused by the arc extinguishing device 7. The arc is extinguished as quickly as possible by a plurality of arc extinguishing plates 51. As described above, a substantially V-shaped groove 51b is formed at the lower end of the notch 51a of the arc-extinguishing plate 51, and this groove 51b is located below the terminal plate ₉₁ as shown in FIG. It is arranged. Therefore, the gas generated around the contact when the circuit is interrupted is quickly discharged to the gas retention section 53 at the rear of the terminal plate ₉₁ through the cut groove 51b.
Furthermore, since the gas discharged into the gas retention section 53 is discharged from the exhaust hole 50a, the amount of arc ejected to the outside can be reduced. In addition to this exhaust hole 50a, an exhaust hole 50b is provided on the opposite side of the arc extinguishing device 7, and the efficiency of gas discharge from the arc extinguishing device 7 is increased by discharging gas in both directions. It is.

Next, FIG. 9 is a sectional view showing a mechanism for adjusting the thermal response characteristics of the bimetal 15. As shown in the same figure, a push-up jig 57 or a push-down jig 58 is inserted into the circuit breaker body 1 through the exhaust hole 50b. The thermal response characteristics of the bimetal 15 can be changed from the outside by being inserted into the bimetal 15. In Figure 9, 5
Reference numeral 9 denotes an adjustment piece formed at the lower end of the terminal plate ₉₂ , which includes a substantially L-shaped opening 60 and a push-up engagement portion 61.
and a push-down engagement portion 62. A projecting piece 14 is provided at the end of the adjusting piece 59,
An engagement hole 15a of a bimetal 15 is fixed to this projecting piece 14. Since the terminal plate ₉₂ is made of a copper plate or a copper alloy plate to improve conductivity, the adjustment piece 59 is relatively easily deformed, and the push-up jig 57 is pushed up to the engagement portion 61. When the adjustment piece 59 is pushed upward by engaging with the adjustment piece 59, the periphery of the approximately L-shaped opening 60 of the adjustment piece 59 is deformed, and the free end of the bimetal 15 is displaced in the direction shown by the arrow Q. Further, when the push-down jig 58 is engaged with the push-down engagement portion 62 and the adjustment piece 59 is pushed down, the periphery of the approximately L-shaped opening 60 of the adjustment piece 59 is deformed in the opposite direction, and the bimetal 15 is The free end is displaced in the direction opposite to arrow Q. Therefore, the gap between the free end of the bimetal 15 and the abutting piece 42 of the latch plate 37 can be adjusted freely.
It is possible to adjust the thermal response characteristics of

Next, FIGS. 10 to 13 show other embodiments, in which three circuit breakers B are installed in parallel.
The circuit breakers B are configured as phase current circuit breakers, and as shown in FIG. 11, the circuit breakers B are fixed to each other by long fixtures 3. Further, a connecting cap 63 is attached to the operating portion of each handle 4, and a connecting shaft 65 is fitted into a horizontal hole 64 formed at the tip of each operating portion.
Each handle 4 is designed to interlock with each other. As shown in FIG. 4, each of the casings 2 ₁ and 2 ₂ of each circuit breaker B has a substantially fan-shaped ridge 66 formed therein. By punching out the inside of the
An interlocking plate 67 can be attached. 1st
Figure 2 shows the position of the movable contact 6 when the interlocking plate 67 is attached and the handle 4 is in the OFF position. It is something that cannot be touched. On the other hand, FIG. 13 shows a state in which one of the circuit breakers B has tripped and the movable contactor 6 has opened, and in this state, the interlocking plate 6
7 is adapted to be pressed by the movable contact 6, and therefore the latch plate 37 of the other circuit breaker B
are pressed by the interlocking plate 67 to rotate, so that the three circuit breakers B are tripped almost simultaneously.

Next, FIGS. 14 to 16 show still other embodiments of the present invention, and parts having the same functions as those in the embodiment shown in FIGS. 1 to 9 are given the same reference numerals. The explanation will be omitted. In this embodiment, a movable contact 6 and a movable arm 17 are integrated, and a thin movable contact 68 having a U-shaped groove 20 and a shaft hole 24 also serves as the movable arm 17. Such a thin movable contact 68
is formed by bending a single copper or copper alloy plate, or the side connected to the braided wire 16 is made of a copper plate or copper alloy, and the other side is made of copper or a copper alloy that is stronger. It is formed by bonding the two together as plates made of iron or other materials with excellent properties. The former method has the advantage of being easy to process and has a large current capacity, while the latter method reduces the cost of parts because plates made of iron or other materials are inexpensive; Since the strength of the plate is stronger than that of a copper plate, the strength of the movable contactor 68 can be increased. The movable contact 8 is attached to one end of the thin movable contact 68 by means such as welding so that the movable contact 8 can be brought into contact with and released from the fixed contact 10. FIG. 15 shows the cross-sectional structure of the circuit breaker of this example in the OFF state,
FIG. 16 shows a cross-sectional view taken along the line Y--Y of the same as above.
As is clear from the above figures, if the thin movable contactor 68 is used, the arc extinguishing chamber 54 and the cutoff mechanism section 55
Since the partition wall 56 that separates the
In addition, since the air resistance against the movable contact 68 is small even during the trip operation, the quick-acting performance can be improved. Furthermore, in this embodiment, the partition wall 56 and the terminal plate 9 ₁
An auxiliary exhaust hole 69 is provided along the casing 2 ₁ , 2 ₂ to quickly release high-temperature gas generated when a short circuit is interrupted to the outside world to prevent insulation deterioration inside the casings 2 1 and 2 2 . .

In the description of the embodiments of the present invention, an overcurrent detection mechanism made of a bimetal 15 and a short-circuit current detection mechanism made of a yoke plate 32 and a magnetic adsorption piece 41 were shown as a load abnormality detection mechanism, but instead of these, It is also possible to use an earth leakage detection mechanism or an open phase detection mechanism as a load abnormality detection mechanism.

The present invention is constructed as described above, and includes a movable contact that is rotatably supported and has a movable contact attached to its tip that makes contact with and separates from a fixed contact, and a movable contact that is rotatably supported and whose tip is rotatably operated. a handle provided with a handle, and a reversing action spring that locks one end side to the handle and locks the other end side to the movable contact so that the reversing movement of the handle follows the reversing movement of the movable contact; A movable member having a pressing portion located on the closing side of the movable contact and capable of pressing the movable contact in the opening direction, which faces the movable contact in an open state when the movable contact is closed. a frame, a spring that biases the movable frame in a direction to move the pressing portion of the movable frame toward the movable contact, and a spring that biases the movable frame in a direction in which the movable frame is biased by the spring; It is composed of a latch plate that is removably engaged with the movable frame, and an abnormality detection mechanism that drives the latch plate in the direction of separation from the movable frame in response to detection of an abnormality in the load. The movable contact and the movable frame are separated from each other, and when the load is abnormal, the movable contact opens the contact by applying a forceful shock to the movable frame in the opening direction using the spring action. Therefore, the opening operation of the movable contact can be made sharper due to its mechanical separation configuration and impact opening configuration.Moreover, when the load is abnormal, the opening operation force is generated by the spring force of the spring. Therefore, it is possible to always ensure a constant and sharp opening operation that is not affected by the magnitude of load abnormality, and it is possible to prevent contact between contacts such as variations in the contact position due to repeated opening and closing operations of the contacts or contact variations due to contact wear. Variations in latch engagement force follow variations in pressure less, and while the operating characteristics can be stabilized,
An arc protection plate for protecting the spring from arcs is attached to the spring so as to be movable as the spring expands and contracts, and a shielding part is provided to protrude from the arc protection plate to protrude between both of the contacts and the contact breaking mechanism during tripping operation. Therefore, the arc protection plate can isolate and protect the spring and contact breaking mechanism from the arc running between the movable contact and the fixed contact during trip operation, improving insulation performance. This has the advantage that the interrupting mechanism can be placed close to the contact portion, and the circuit breaker can be made smaller. Moreover, since the arc protection plate is designed to protrude during the tripping operation and is normally retracted, it does not interfere with the operation of the movable contactor having the movable contact.
Moreover, the interrupting part that protrudes between both contacts and the contact interrupting mechanism, and the arc protection plate that protrudes from it, do not operate in conjunction with the handle for opening and closing the circuit, and operate only when the trip is performed. The arc protection plate and cut-off part are not operated during opening and closing operations, and the arc protection plate and cut-off part are operated only when necessary, preventing the arc protection plate and cut-off part from rubbing against the casing, etc., and reducing wear and tear on these parts. This has the advantage that the functions of the arc protection plate and the interrupting part do not have to be unnecessarily shortened, stable operation can be performed over a long period of time, and reliability can be improved.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the external appearance of a circuit breaker according to an embodiment of the present invention, Fig. 2 is a perspective view of the same with both casings opened, and Figs. 3 and 4 are the components of the same. FIG. 5 is a cross-sectional view of the above circuit breaker in the off state, FIG. 6 is a cross-sectional view taken along the line X-X of the above, and FIG. 7 is a cross-sectional view of the above circuit breaker in the on state. Figure 8 is a cross-sectional view of the circuit breaker as described above in a tripped state, Figure 9 is a cross-sectional view showing an adjustment mechanism for the thermal response characteristics of a bimetal used in the circuit breaker as described above, and Figure 10 is another implementation of the same as above. FIG. 11 is an exploded perspective view of the same example; FIGS. 12 and 13 are cross-sectional views of the same in the OFF state and trip state, respectively; FIG. 14 is an exploded perspective view of still another embodiment of the same. , 15th
The figure is a sectional view of the same as above in the OFF state, Fig. 16 is a sectional view taken along the Y-Y line of the same as above, Fig. 17 is a perspective view showing the spring and arc protection plate, and Fig. 18 is a state in which the spring and arc protection plate are arranged. FIG. 19 is a side view of a conventional example. 8...Movable contact, 10...Fixed contact, 27...
Spring, 28... Arc protection plate, 28d...
Shielding part, 95...Contact breaking mechanism.

Claims (1)

[Claims] 1. A movable contact that is rotatably supported and equipped with a movable contact that connects and separates from a fixed contact at the tip, a handle that is rotatably supported and has a handle that can be rotated at the tip, and this handle. a reversing action spring that locks one end side and locks the other end side to the movable contact so that the reversing operation of the movable contact follows the reversing operation of the handle; and a reversing action spring located on the closing side of the movable contact. a movable frame provided with a pressing part capable of pressing the movable contact in the opening direction, which faces the movable contact in an open state when the movable contact is closed; a spring that biases the movable frame in a direction toward the movable contact; a latch plate that is releasably engaged with the movable frame so as to prevent the movable frame from moving in the spring-biased direction;
The circuit breaker includes an abnormality detection mechanism that drives the latch plate in the direction of detachment from the movable frame in response to detection of an abnormality in the load, and an arc protection plate for protecting the spring from arcing. Attaches to a spring so that it can move freely as it expands and contracts.
It is characterized by comprising a shielding part that protrudes from the arc protection plate and protrudes between both contacts, the movable frame, the spring, and the latch plate only during the trip operation and is not linked to the rotational operation of the handle for opening and closing the circuit. circuit breaker.