JPH0133020B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] 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 is detected in the load. be.

[Background technology]

In conventional circuit breakers of this type, the center of rotation of the movable contact and the center of rotation of the movable frame are the same, so wiping action cannot be obtained between the movable contact of the movable contact and the fixed contact, resulting in contact There was a problem with lack of reliability.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a circuit breaker in which contact reliability is improved by adding a wiping operation to the opening operation of a movable contact. be.

[Disclosure of the invention]

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. The circuit breaker main body 1 has a handle 4 protruding from the upper surface thereof for opening and closing the circuit. 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 . As shown in the figure, there is a pair of casings 2 ₁ and 2 ₂ between them. External connection terminal 5 ₁ ,
5 ₂ , a movable contactor 6, and an arc extinguishing device 7. 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 engagement hole 15a of the bimetal 15 for overcurrent detection is fitted into the protruding piece 14 protruding from the terminal plate ₉₂ , so that the protruding piece 14 is inserted and the bimetal 15 is fixed to the terminal plate ₉₂ . It's summery. 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.
The movable contactor 6 is connected to a movable arm 17 and pivotally supported by a rotating shaft 19 (described later) via the movable arm 17, and the movable arm 17 is fitted into a bottom opening 18a of a movable frame 18. It's starting to become easier. Reference numeral 19 denotes a rotating shaft for supporting the handle 4, the movable arm 17, and the movable frame 18. They are designed to fit together. Further, as shown in FIG. 9, the substantially central portion of both ends 19b of the rotating shaft 19 is made eccentric by shearing or the like so that the outer end 19A side is slightly upwardly eccentric than the inner end 19B side, and the inner end 19B side is fitted into the U-shaped groove 20 that serves as the pivot point of the movable arm 17, and the outer end 19A is fitted into the pivot hole 21 of the movable frame 18.
and a U-shaped groove 22. 23 is a tension spring for biasing the handle 4 to the on position and the off position. One end of the tension spring 23 is engaged with the central portion 19a of the rotating shaft 19, and the other end is engaged with a pin 25 whose both ends are supported in the shaft hole 24 of the movable arm 17. Therefore, the handle 4 is as shown in FIGS. 5 and 7.
As shown in the figure, the tension spring 23 is biased toward the on position or the off position at a point where the tension spring 23 crosses the rotation center P of the rotating shaft 19. Furthermore, the movable arm 17, the movable frame 18, and the rotating shaft 19 can be integrated by the tensile force of the tension spring 23. 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, reference numeral 27 is a compression coil type spring for forcibly opening the movable contactor 6 during the trip operation, and the tip end 27a of this spring 27 is connected to the spring receiver of the movable frame 18 via a protective plate 28 for preventing arcing. It is adapted to be inserted into and engaged with an engagement hole 29 provided in the seat 31. This spring 27 has both casings 2 ₁ ,
2 It is stored in the storage space 30 of ₂ , and its deep bottom surface 3
The rear end 27b of the spring 27 is brought into contact with the spring 27. Arc protection plate 28
This is to prevent the spring 27 from being melted and damaged by the arc that occurs when the movable contact 8 of the movable contact 6 separates from the fixed contact ₁₀ of the terminal plate 91. and a side protection plate 28b. Further, the front protection plate 28a is provided with a fitting hole 18c into which the tip end 27a of the spring 27 is fitted. The front protection plate 28a and the spring seat 31 around the engagement hole 29 of the movable frame 18 are slightly inclined to improve contact with the spring 27. 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 . It is designed to be fixed by a matching hole 34. The center piece 35 of the yoke plate 32 is fixed to the terminal plate 9 ₂ , and side pieces 3 forming a magnetic connection path are attached from both sides of the center piece 35 .
6 extends vertically. 37 is a latch plate, and the pivot pin 3 is inserted into the pivot hole 38 of the latch plate.
Both ends of 9 are the engagement holes 40 of both casings 2 ₁ and 2 ₂
This makes the latch plate 37 rotatable. This latch plate 37 is made of a magnetic material, and when an excessive current flows through the bimetal 15, the magnetic flux generated around the bimetal 15 flows to the center piece 35 and side pieces 36 of the yoke plate 32, and the latch plate 37 The magnetic adsorption piece 41 is adapted to be adsorbed to the side piece 36. Further, an abutment piece 42 is formed at the upper end of the latch plate 37, and is adapted to abut against the free end side of the bimetal 15. Therefore, both sides 43 of the latch plate 37
A locking step portion 44 is formed at the tip of the movable frame 18, and is adapted to abut against a locking portion 45 of the movable frame 18. 46 is a torsion spring that presses the contact piece 42 of the latch plate 37 toward the free end side of the bimetal 15;
As shown in FIGS. 5 and 7, this one end abuts against the back side of the contact piece 42 of the latch plate 37, and the other end abuts against the handle 4 when the handle 4 is in the OFF position, and when the handle 4 is in the ON position. When it is in the position, it comes into contact with the casings 2 ₁ and 2 ₂ , and the force applied to the latch plate 37 is changed depending on the state of the handle 4. 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 ,
2 ₂ also includes a shaft support hole 48 for supporting both ends 19b of the rotating shaft 19, a hole 49 for fitting the fixture 3, and an exhaust hole 50a for exhausting gas generated when the circuit is interrupted. 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. A substantially V-shaped cut groove 51b is formed at the lower end of the cutout 51a.
The gas accumulated around the contact is transferred to the fixed contact 1 via b.
By discharging the gas into a gas retention section 53 formed at the rear of the 0, the shutoff performance can be improved. In addition, a partition wall 56 is formed between the arc extinguishing chamber 54 that stores the arc extinguishing device 7 and the disconnection mechanism section 55 that stores the contact disconnection mechanism such as the spring 27 and the movable frame 18. Room 5
This prevents the arc from 4 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 the short-circuit current flowing through the bimetal 15 and attracts the magnetic attraction piece 41, the latch plate 37 is adapted to rotate around a 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 moved. It is designed to rotate around 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, since the movable frame 18 is pressed by the spring 27 and rotates, the movable contactor 6 is attached to the movable frame 1.
It is pushed by the opening edge of the bottom opening 18a of No. 8 and is forcibly driven in the contact opening direction. At this time, since the rotation center of the movable contact 6, that is, the rotation center of the movable arm 17, is offset from the rotation center of the movable frame 18, the movable contact 6 is wiped in the direction of the arrow X as shown in FIG. At the same time, the contact is opened in the Y direction, and the cleaning effect between the movable contact 8 and the fixed contact 10 is obtained by wiping. Now, 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, and the movable arm 17 is stopped, and the handle 4 is stopped at a position where the groove 4b is engaged 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,
As shown in FIG. 5, the handle 4 cannot be stopped at the on position 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 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 equal to
The movable contactor 6 is formed to be longer than the opening/closing stroke of the spring 27, the movable frame 18, and the latch plate 37 when a trip operation is not performed such as during manual opening/closing operation. It is not affected by the mechanism. 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. Locking step part 4 due to vibration
4 and the locking portion 45 can be less likely to become disengaged.

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.

〔Effect of the invention〕

According to the present invention, in the circuit breaker configured as described above, the shaft support positions of the movable frame at both ends of the rotating shaft are eccentric to the shaft support positions of the movable contact.
A wiping action can be applied to the movable contact when the contact is opened, and the wiping provides an effect of cleaning between the fixed contact and the movable contact, and the reliability of contact 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. Fig. 8 is a cross-sectional view of the circuit breaker in the tripped state, Fig. 9 is a perspective view of the rotating shaft used in the above, and Fig. 10 is an explanatory view of the main parts of the same. Movable contact, 8 is a movable contact, 10 is a fixed contact, 15 is a bimetal, 19 is a rotating shaft, 19a is a central part, 19
b is both ends, 19A is an outer end, 19B is an outer end,
23 is a tension spring, and 27 is a spring.

Claims (1)

[Claims] 1. A rotating shaft whose central part is bent into a substantially U-shape,
A handle whose lower end is pivoted at the center of the rotating shaft and whose upper end is rotatable, a movable frame where both ends of the rotating shaft are pivoted, and the upper ends of both pieces are pivoted at both ends of the rotating shaft. Both ends of the upper end are supported by the supported movable frame, and both ends of the rotating shaft are supported inside the pivot positions for the movable frame at both ends of the rotating shaft. A movable contact with a movable contact attached to the lower end of the handle, a spring that reverses the action between the handle and the movable contact, a fixed contact that comes into contact with and separates from the movable contact when the handle is rotated, and a load abnormality. An abnormality detection mechanism that responds to the detection, a spring that biases the movable contact in a direction that separates the movable contact and the fixed contact, and a spring that normally holds the spring so that the biasing force of the spring is not applied to the movable contact. and a latch mechanism that releases the holding operation of the spring in the event of a load abnormality.In the circuit breaker, the pivot position of the movable frame at both ends of the rotating shaft is connected to the axis of the movable contact. A circuit breaker characterized by being eccentric with respect to a branch position.