JPH0131652B2 - - 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.

Conventionally, the present inventor has developed a circuit in which a contact opening/closing mechanism that opens and closes the main contacts by operating a handle and a contact breaking mechanism that forcibly opens and closes the main contacts when an abnormality is detected in the load can be configured separately from each other. We have been working on the development of circuit breakers. However, such circuit breakers have a problem in that vibrations caused when the handle is manually opened/closed can unlatch the contact interrupting mechanism and cause the main contacts to open, making them more likely to malfunction. .

The present invention has been made to solve these problems of the conventional example, and even if a small amount of vibration is applied to the contact cutoff mechanism when manually opening and closing the handle, the contact cutoff mechanism will not latch. It is an object of the present invention to provide a circuit breaker which can be prevented from becoming disconnected and which reduces the possibility of malfunction.

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. Fig. 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. This spring 27 is housed in the storage space 30 of both 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 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, and serves as a front protection. It is composed of a plate 28a and a side protection plate 28b. Further, the front protection plate 28a has a tip 27a of the spring 27.
A fitting hole 28c for fitting is provided. The front protection plate 28a and the spring seat 31 around 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 are connected to respective engagement plates formed on the pair of casings 2 ₁ and 2 ₂ . Matching hole 3
It is designed to be fixed by 4. The center piece 35 of the yoke plate 32 is 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 part 53 formed behind the fixed contact 10. This makes it possible to improve the interrupting performance. Furthermore, a partition wall 56 is formed between the arc extinguishing chamber 54 in which the arc extinguishing device 7 is housed and the cutoff mechanism section 56 in which the spring 27, movable frame 18, etc. are housed. This prevents arcs 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. When the movable contact 6 is opened by a predetermined distance, it is further driven in the contact opening direction by the tensile force of the tension spring 23, and finally the movable arm 17
comes into contact with the pivot pin 39, the movable arm 17 stops, and the handle 4 stops at a position where the groove 4b engages with the protrusion 26 of the movable frame 18. 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, unless the handle 4 is returned to the OFF position and the engagement between the locking step portion 44 and the locking portion 45 is restored as shown in FIG. 5, the handle 4 will remain in the ON position. It cannot be stopped. 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 a tripping action is not performed, such as during operation, the movable contactor 6 is not affected by contact breaking mechanisms such as the spring 27, the movable frame 18, and 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. It is possible to reduce the possibility that the locking step portion 44 and the locking portion 45 will come out of engagement due to vibration.

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, FIGS. 9 and 10 show cross-sectional views of other embodiments of the present invention, in which a torsion spring 46 as well as the above-mentioned torsion spring 46 is used as a spring material for pressing the abutment piece 42 of the latch plate 37. A leaf spring 57 having a structure as shown in FIGS. 11a and 11b is also used. In this embodiment, one end of the torsion spring 46 is in contact with the casings 2 ₁ , 2 ₂ , and therefore the pressure force applied to the contact piece 42 by the other end of the torsion spring 46 is There is not much difference between when the handle 4 is in the on position and when it is in the off position. That is, in this embodiment, the torsion spring 46 is used to constantly apply a substantially constant pressing force to the abutment piece 42 of the latch plate 37. On the other hand, the leaf spring 57 is made of a highly elastic metal plate.
It is formed by bending as shown in FIGS. 1a and 1b, and the base portion 57a of this leaf spring 57 is fixed in contact with the casings 2 ₁ and 2 ₂ .
Further, when the handle 4 is in the off position, the curved portion 57b of the leaf spring 57 comes into contact with the outer peripheral surface of the handle 4 as shown in FIG. The piece 42 is strongly pressed. Therefore, the locking step 4 of the latch plate 37
4, the locking part 45 of the movable frame 18 is reliably engaged with the handle 4, and the locking part 44 and the locking part 45 are not disengaged due to vibration when manually opening and closing the handle 4. This prevents malfunctions from occurring. Next, when the handle 4 is in the on position, the curved portion 57b of the leaf spring 57 does not come into contact with the outer peripheral surface of the handle 4 and is suspended in the air, as shown in FIG. The pressure contact portion 57c does not contact the contact piece 42 of the latch plate 37. Therefore, in this case, the abutting piece 42 of the latch plate 37 is pressed only by the torsion spring 46. In this embodiment, the pressure force of the latch plate 37 against the abutting piece 42 is changed between on and off states by the leaf spring 57, so that the torsion spring 46
The amount of displacement of the torsion spring 46 can be kept small, so even after many years of use, the torsion spring 46 is less fatigued, and the pressure contact force by the torsion spring 46 is less likely to go out of order, thus reducing fluctuations in operating characteristics. It is something that can be done.

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 is provided with a spring material that applies a pressing force to the latch mechanism in the direction of increasing the latching force of the latch mechanism, and when the handle is in the off position, the spring material is applied to the handle. When the spring material comes into contact with a portion of the handle, the pressing force against the latch mechanism becomes strong, and when the handle is in the on position, the contact between the spring material and a portion of the handle is released, and the pressing force against the latch mechanism is reduced. Since the above-described spring material is provided, the latching force of the latch mechanism is strong when the handle is in the off position, and therefore the latching action of the latch mechanism is released by vibrations when the handle is opened/closed. This has the advantage that malfunctions can be reduced, and when the handle is in the on position, the spring material and a portion of the handle are released from contact, and the pressure force against the latch mechanism is reduced. Therefore, the latch operation of the latch mechanism is immediately released when an overcurrent or short circuit current is detected, which has the advantage that the response speed of the circuit breaker does not decrease. It is something.

[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 FIG. 5, and FIG. 7 is a cross-sectional view of the above circuit breaker in the ON state. 8 is a sectional view of the circuit breaker of the same type in the tripped state, FIG. 9 is a sectional view of the circuit breaker of the same example in the OFF state, and FIG. 10 is a sectional view of the circuit breaker of the same type in the OFF state. FIG. 11a is a side view of the leaf spring used in the on-state, and FIG. 11b is a front view of the same. 4 is a handle, 6 is a movable contact, 8 is a movable contact, 10 is a fixed contact, 27 is a spring, 37 is a latch plate, 46 is a torsion spring, and 57 is a leaf spring.

Claims (1)

[Claims] 1. A rotatable movable contact with a movable contact attached to one end, a fixed contact that contacts and releases the movable contact by the rotation of the movable contact, and a handle that manually rotates the movable contact. , a spring that biases the movable contact in the direction in which the movable contact and the fixed contact open and separate, and a spring that normally holds the spring so that the biasing force of the spring is not applied to the movable contact, and in the event of an abnormal load, the spring A circuit breaker having a latch mechanism that releases the holding operation of the circuit breaker is provided with a spring member that applies a pressure contact force to the latch mechanism in a direction that strengthens the latching force of the latch mechanism, and when the handle is in the off position. When the spring material comes into contact with a part of the handle, the pressure contact force against the latch mechanism becomes strong, and when the handle is in the on position, the contact between the spring material and the part of the handle is released and the pressure contact force against the latch mechanism increases. A circuit breaker characterized in that the spring material is arranged at a position such that the spring material is relieved.