JPH0158814B2 - - 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.

A conventional circuit breaker is constructed as shown in FIG. 11, and as shown in the figure, the circuit breaker has a rotatable movable contact 6 with a movable contact 8 attached to one end, and a movable contact 6. The movable contact 8 is moved by the rotational movement of 6.
An overcurrent detection mechanism consisting of a fixed contact 10 that contacts and opens when an overcurrent is detected, a handle 4 that manually rotates a movable contact 6, and a bimetal 15, and a movable contact 8 and a fixed contact 10 that open when an overcurrent is detected. It includes a contact breaking mechanism 55a that drives the movable contact 6 in the direction of separation, an arc extinguishing device 7, and the like. Reference numeral 71 is an adjustment screw for adjusting the detection level of the overcurrent detection mechanism made of bimetal 15, and is provided at a portion of the circuit breaker body 1 corresponding to the adjustment window 72. Therefore, when adjusting the overcurrent interrupting characteristics of the circuit breaker, an adjustment jig such as a screwdriver is inserted through the adjustment window 72 of the circuit breaker body 1, and the adjustment screw 71 is inserted.
After the adjustment work is completed, the adjustment window 72 is closed with a lid body 73. In this way, in the conventional example, after the characteristic adjustment work of the circuit breaker is completed, the adjustment window 72 is closed.
Therefore, for example, the lid body 7
There was a problem in that work such as applying adhesive to the parts 3 had to be done.

The present invention has been made in order to solve these problems of the conventional example, and its purpose is to provide a circuit breaker that does not require closing the adjustment window after the characteristic adjustment work is completed. be.

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 main 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 . 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, and FIG. 9 shows a sectional view of essential parts of the present invention. 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 contact 6 is connected to a movable arm 17, and the movable arm 17 is adapted to be fitted into a bottom opening 18a of a movable frame 18. 19
is a rotating shaft for pivotally supporting the handle 4, 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.
It is adapted to fit into a groove 4a of the handle 4. 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 getting old. 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, as shown in FIGS. 5 and 7,
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. Therefore, a protruding step 26 is formed at one end of the movable frame 18, and this protruding step 26
The groove 4b of the handle 4 can be engaged with the handle 4 as shown in FIG. 3, thereby preventing the handle 4 from popping out in the direction shown by arrow A during the circuit breaker assembly process. This is something that can be prevented. 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. 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, and serves as a front protection. Board 28
a and a side protection plate 28b. 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 around the engagement hole 29 of the movable frame 18 are slightly inclined to improve contact with the spring 27. 32 is a yoke plate for short-circuit current detection formed of a magnetic material, and this yoke plate 3
The side projecting pieces 33 protruding from the casings 2 are fixed by engagement holes 34 formed in the pair of casings 2 ₁ and 2 ₂ respectively. Yoke plate 3
The center piece 35 of 2 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 its pivot hole 38
Both ends of the pivot pin 39 inserted through the latch plate 37 are supported by the engagement holes 40 of both the casings 2 ₁ and 2 ₂ , making the latch plate 37 rotatable. This latch plate 3
7 is made of a magnetic material, and when an excessive current flows through the bimetal 15, the magnetic flux generated around the bimetal 15 is caused by the central piece 35 of the yoke plate 32.
and flows to the side piece 36, so that the magnetic attraction piece 41 of the latch plate 37 is attracted 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, the end portions of both side pieces 43 of the latch plate 37 have locking steps 4.
4 is formed so as to come into contact with a locking portion 45 of the movable frame 17. 46 is the latch plate 37
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 the handle 4 is in the OFF position, and contacts the casings 2 ₁ and 2 ₂ when the handle 4 is in the ON position. Depending on the state of the handle 4, the latch plate 37
changing the force applied to 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 ends 1 of the rotating shaft 19 are attached to both casings 2 ₁ and 2 ₂ .
A shaft support hole 48 for supporting the shaft 9b, a hole 49 for inserting the screw 3, and exhaust holes 50a and 50b for exhausting gas generated when the circuit is interrupted are provided. Furthermore, 7 is an arc extinguishing device,
It is formed by holding a plurality of arc extinguishing plates 51 made of magnetic material at appropriate intervals with side plates 52 made of insulating material, and when the movable contact 8 and the fixed contact 10 are separated, It is designed to extinguish the arc that occurs 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 notch 51a, and the gas accumulated around the contact is transferred via the cut groove 51b to a gas retention part 53 formed behind the fixed contact 10.
By discharging the water, the shutoff performance can be improved. Also, arc extinguishing device 7
an arc extinguishing chamber 54 that stores the spring 27, the movable frame 18, etc.
A partition wall 56 is formed between the arc extinguishing chamber 54 and the arc extinguishing chamber 54 to prevent the arc from entering the cutoff mechanism section.

Next, the operation of the circuit breaker 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
They are separated to a position where they come into contact with the opening edge of a. 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 abutting piece 42 of the latch plate 37.
Therefore, the locking portion 45 of the movable frame 18 is connected to the latch plate 3.
It is securely engaged with the locking step portion 44 of No.7. Further, due to this engagement, the spring 27 for tripping operation is interposed within the storage space 30 while being compressed. FIG. 6 shows a cross-sectional view taken along the line X-X in FIG. You can clearly see what's going on. 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, so that the operation part of the handle 4 is connected to the casing 2 ₁ ,
2 It is stopped at the position where it touches ₂ . In this manner, the direction in which the movable contactor 6 and the operating portion of the handle 4 are biased is reversed at the point where the tension spring 23 crosses the rotation center P of the rotation shaft 19. Therefore, when the circuit breaker is on, one end of the torsion spring 46 is no longer pressed against the outer peripheral surface of the handle 4, as shown in FIG. The pressing force is weaker than in the state shown in FIG. 3, and a desired force is applied to the contact piece 42. Therefore, if the bimetal 15 deforms due to overcurrent and presses against the contact piece 42, or if the yoke plate 3
2 is magnetized by the short-circuit current flowing through the bimetal 15 and attracts the magnetic attraction piece 41, the latch plate 37 rotates around the pivot pin 39, thereby engaging the latch plate 37. When the stop portion 44 and the locking portion 45 are disengaged, the spring 27 is expanded, and the movable frame 18 rotates 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 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 contact breaking mechanisms 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 the torsion spring 46 is turned off, so vibrations caused when the handle 4 is manually opened and closed are This can reduce the risk of disengagement between the locking step portion 44 and the locking portion 45.

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 shows the bimetal 1 which is the main part of the present invention.
5 is a cross-sectional view showing the adjustment mechanism of the thermal response characteristics of No. 5,
As shown in the 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, so that the thermal response characteristics of the bimetal 15 can be changed from the outside. It is something. In FIG. 9, reference numeral 59 denotes an adjustment piece formed at the lower end of the terminal plate ₉₂ , which has an approximately L-shaped opening 60.
, a push-up engagement portion 61 and a push-down engagement portion 62. A projecting piece 1 is attached to the end of this adjustment piece 59.
4 is provided in a protruding manner, and an engagement hole 15a of a bimetal 15 is fixed to this protruding piece 14. However, since the terminal plate ₉₂ is formed of a plate of copper or copper alloy 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 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 moved in the direction of the arrow Q.
Displaced in the direction shown. Furthermore, 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, causing the bimetal 15 to be free. The 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, thereby making it possible to adjust the thermal response characteristics of the bimetal 15.

Next, FIGS. 10a to 10c show other embodiments of the present invention. First, FIG. 10a shows an arrangement in which the adjusting screw 63 is rotated by a driver 64, and FIG. Approximately rectangular opening 6 of adjustment piece 59
5 is pressed by a pressing jig 66 or twisted by a twisting jig 67. Further, in FIG. 3c, the edge portion 70 of a wedge-shaped jig 69 is press-fitted into the cut groove portion 68 of the adjustment piece 59. As described above, the thermal response characteristics of the bimetal 15 can be adjusted via the exhaust hole 50b using any of the structures shown in FIGS. 9 and 10 a to 10 c.

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, and in this case, a variable resistor for adjusting characteristics can be connected to the exhaust hole 50
It is only necessary to dispose it near b so that it can be operated from the outside.

The present invention is configured as described above, and includes a rotatable movable contact with a movable contact attached to one end;
A fixed contact that contacts and opens the movable contact by rotating the movable contact, a handle that manually rotates the movable contact, and a load abnormality detection mechanism such as an overcurrent detection mechanism or an earth leakage detection mechanism. , a circuit breaker having a contact breaking mechanism that drives a movable contact in a direction in which a movable contact and a fixed contact are opened when a load abnormality is detected, and an exhaust hole that discharges gas generated when the contact is broken to the outside of the circuit breaker body. In this case, the detection level adjustment device of the load abnormality detection mechanism is provided near the exhaust hole and can be operated from the outside.
By inserting an adjustment jig through the exhaust hole, the characteristics of the circuit breaker can be adjusted from the outside, and there is no need to close the exhaust hole even after the adjustment work has been completed, making it possible to adjust the characteristics of the circuit breaker from the outside. This has the advantage that work such as gluing the lid to the adjustment window is not necessary.

[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 same circuit breaker in a tripped state; FIG. 9 is a cross-sectional view of a main part of the same embodiment; FIGS. FIG. 11 is a sectional view of a conventional example. 1 is a circuit breaker main body, 4 is a handle, 6 is a movable contact, 8 is a movable contact, 10 is a fixed contact, 15 is a bimetal, 50b is an exhaust hole, and 59 is an adjustment piece.

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 load abnormality detection mechanism such as an overcurrent detection mechanism and an earth leakage detection mechanism, a contact breaking mechanism that drives a movable contact in a direction in which a movable contact and a fixed contact are opened when a load abnormality is detected, and a contact breaking mechanism that drives a movable contact in a direction in which a movable contact and a fixed contact are opened when a load abnormality is detected. In a circuit breaker having an exhaust hole for discharging generated gas to the outside of the circuit breaker body,
A circuit breaker characterized in that a detection level adjustment device for a load abnormality detection mechanism is provided near the exhaust hole and can be operated from the outside.