JPH0142928Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] The present invention relates to a circuit breaker that utilizes the heat-generating deformation of a bimetal to trip the latch of a latch mechanism to separate the movable contact and the fixed contact of the movable contactor. be.

[Background technology]

Conventionally, the adjustment screw used in this type of circuit breaker to adjust the pushing degree of the bimetal was made by drilling a female threaded hole in the free end of the bimetal, and screwing the adjustment screw into this female threaded hole. When the effective length of the female screw hole is short, an auxiliary member such as a lock nut is used to prevent the adjustment screw from wobbling. Furthermore, when a lock nut or the like is not used, the accuracy of the fit between the diameter of the female screw hole and the outer diameter of the adjustment screw is increased.

However, when auxiliary members are used, the assembly work becomes complicated, and the latter method has the drawback of increasing the cost due to the high processing accuracy.

[Purpose of invention]

This invention was created in view of the above-mentioned drawbacks.
The purpose of this is to eliminate the wobble of the adjustment screw without using special auxiliary parts or increasing the machining accuracy.
An object of the present invention is to provide a circuit breaker that can improve the accuracy of characteristic calibration.

[Disclosure of 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 2 ₂ connected to each other by screws or rivets. 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 is removed and one casing 2 ₁ is 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 5 ₂ , a movable contactor 6, and an arc extinguishing device 7 are housed between the terminals 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. Each terminal board 9 ₁ 9 ₂ has a washer 11
A tightening screw 13 is attached via 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 inserted into the protruding piece 14 protruding from the terminal plate ₉₂ , and the protruding piece 14 is caulked, so that the bimetal 15 is fixed to the terminal plate ₉₂ . It's getting old. 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. Also bimetal 1
One corner of the free end of 5 is cut off diagonally, and a female screw hole 1 is provided at a position very close to the oblique side of this cut off part.
5b is bored, and an adjusting screw 57 for adjusting the degree of pressing when pressing the latch plate 37, which will be described later, is screwed into this female threaded hole 15b. Figures 9 a to e show this bimetal 15 and adjustment screw 5.
To explain this process, first, as shown in figure a, a screw is first inserted in the vicinity of the outer edge of the cut-off portion of the free end of the bimetal 15. Drill a pilot hole 15b' and tap this screw pilot hole 15b' as shown in Figure b.
The female threaded hole 15b is formed in the following manner. During this tapping process, the thin part x escapes outward in the direction of the arrow, and after the tapping process is completed, the thin inner part x springs back into the female threaded hole 1, as shown in Figure b.
5b is not a perfect circle, and therefore, when the adjusting screw 57 is screwed together, a force in the F direction shown in the figure c acts to pinch the adjusting screw 57 into the female threaded hole 15b, making it tightly screwed together. Hold the condition and adjust the adjustment screw 57.
This eliminates the wobbling and makes it possible to screw the adjustment screw 57 forward and backward as shown by the arrow e in the figure with a moderate rotational torque.
In the figure, reference numeral 58 denotes a hole into which the adjusting screw 57 is inserted with an adjusting driver. The movable contactor 6 is caulked 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. Reference numeral 19 denotes a rotating shaft for pivotally supporting the handle 4, movable arm 17, and movable frame 18, and the center portion 19 of this rotating shaft 19
a is bent into a substantially U-shape so as to fit into a groove 4a in the handle 4. Also, the rotation axis 1
Both end portions 19b of the movable arm 17 are fitted into U-shaped grooves 20 that serve as pivot points of the movable arm 17, and the movable frame 1
8 and the 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, 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. . 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 a handle 4 is attached to this protrusion 26.
The recessed groove 4b of the circuit breaker can be engaged as shown in FIG. 3, thereby preventing the handle 4 from popping out in the direction shown by arrow A during the assembly process of the circuit breaker. It is a familiar thing.
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 is housed in the storage space 30 of both casings 2 ₁ 2 ₂ , and the rear end 27b of the spring 27 comes into contact with the inner bottom surface 30a. The arc protection plate 28 has the movable contact 8 of the movable contactor 6 connected to the terminal plate 9.
This prevents the spring 27 from being melted and damaged by the arc generated when the _first fixed contact 10 is separated from the other, and is composed of a front protection plate 28a and a side protection plate 28b. Also, the front protection plate 2
8a is provided with a fitting hole 28c into which the tip 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 formed to be slightly inclined to improve contact with the spring 27. 3
Reference numeral 2 denotes a yoke plate for short-circuit current detection formed of a magnetic material, and side protruding pieces 33 protruding from this yoke plate 32 are engaged with each other formed on the pair of casings 2 ₁ 2 ₂ respectively. It is adapted to be fixed by a hole 34. Central piece 35 of yoke plate 32
are fixed to the terminal plate ₉₂ by caulking, and side pieces 36 forming magnetic 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 casings 2 ₁ 2 ₂ , making the latch plate 47 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 is transferred to the center piece 35 and side pieces 36 of the yoke plate 32.
The magnetic attraction piece 41 of the latch plate 37 is attracted to the side piece 36 by the magnetic attraction piece 41 of the latch plate 37. Further, an abutment piece 42 is formed at the upper end of the latch plate 37.
It is designed to come into contact with the free end side of the bimetal 15. A locking stepped portion 44 is formed at the tip of each side piece 43 of the latch plate 37, and is adapted to abut against a locking portion 55 of the movable frame 17. Reference numeral 46 denotes 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. abutting the side,
The other end contacts the handle 4 when it is in the off position, and contacts the casing 2 ₁ 2 ₂ when it is in the on position, changing the force applied to the latch plate 37 depending on the state of the handle 4. The torsion spring 46 is pivotally supported by fitting into the pivotally supporting boss 47 ₁ of the casing 2 ₁ , and
On the other hand, it is adapted to be received by a pivot boss 47 ₂ of the casing 2 ₂ . 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 50a50b for exhausting gas generated in the circuit breaker. 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 groove 51b is formed at the lower end of this notch 51a.
The gas accumulated around the contact is removed from the fixed contact 10 through
The shutoff performance can be improved by discharging the gas into a gas retention section 53 formed at the rear. Additionally, there is an arc extinguishing chamber 54 that houses the arc extinguishing device 7, a spring 27, and a movable frame 1.
A partition wall 56 is formed between the arc extinguishing chamber 54 and the interrupting mechanism section 55 in which the arc extinguishing chamber 54 is stored, thereby preventing the arc from entering the interrupting 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 abutting piece 42 of the latch plate 37. Therefore, the locking portion 45 of the movable frame 18 is connected to the locking step portion 44 of the latch plate 37.
is securely engaged. Also, 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.
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 casing 2 ₁ 2 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 heats up and deforms due to overcurrent and presses the abutment piece 42 of the latch plate 37 via the adjustment screw 57b, or if the yoke plate 32 becomes magnetized by the short-circuit current flowing through the bimetal 15. When the magnetic attraction piece 41 is attracted, the latch plate 37 rotates around the pivot pin 39, thereby causing the locking step portion 44 and the locking portion 45 to engage with each other. When the alignment is removed, the spring 27 is expanded, and the movable frame 18 is rotated about the rotation center P of the rotating shaft 19. FIG. 8 shows a state in which such a tripping operation has been performed. As shown in the figure, the movable frame 18 is pressed by the spring 27 and rotates, so the movable contact 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. 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
The movable arm 17 is stopped when it comes into contact with the pivot pin 39, 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, unless the handle 4 is returned to the OFF position and the engagement between the locking step 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. In addition, in this embodiment, the torsion spring 4
Since one end of the latch plate 37 is separated from the handle 4, the abutting piece 42 of the latch plate 37 is strongly pressed when the latch plate 37 is turned off, so that it is locked to the locking step 44 by vibration when manually opening and closing the handle 4. It is possible to reduce the risk of disengagement from the 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 via 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 idea]

The present invention is constructed as described above, in which the bimetal is composed of a long plate having a fixed end side and a free end side, and the free end side of the bimetal is formed with an inclined side with respect to the longitudinal direction, so that the side is inclined more than the other sides. A small-diameter female threaded hole was formed adjacent to this inclined side, and an adjustment screw for adjusting the pushing force of the abutting piece of the latch mechanism was screwed into this female threaded hole so that the adjusting screw could be screwed freely between the inclined side and the adjacent side. The mating sides touch at an obtuse angle, and when viewed from the female screw hole, the width of the plate increases in the direction away from the inclined surface, so the widening of the hole that occurs when an adjustment screw is screwed into a small diameter female screw hole is the same as the slope side. The sides adjacent to the metal are sufficiently protected and can be pushed out in the direction of the inclined sides, so the direction of expansion is stabilized, and at the same time sufficient elasticity can be secured from the surrounding configuration of the female threaded hole, resulting in the bimetal backing. This has the effect of stably obtaining a spring and further reducing wobbling of the adjustment screw, so when tapping a pilot hole for a screw, the thin walled area at the outer edge of the drilled member is pushed outward, completing the tapping process. Occasionally, a spring back appears in this area, and as a result, the female screw hole is not a perfect circle, and when the adjustment screw is screwed together, the adjustment screw is held by the spring back area so that it is held between the inner edges of the female screw hole. It has the advantage of preventing the screw from wobbling and therefore improving the calibration accuracy when calibrating characteristics.Furthermore, there is no need for special auxiliary members and there is no need to increase processing accuracy. This has the advantage of reducing costs.

[Brief explanation of the drawing]

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 sectional view of the same circuit breaker in the tripped state, Figures 9 a to e
is an explanatory diagram of the bimetal processing process as above, and
4 is a handle, 6 is a movable contact, 8 is a movable contact,
10 is a fixed contact, 15 is a bimetal, 15b is a female screw hole, 18 is a movable frame, 23 is a tension spring, 27 is a spring, 37 is a latch plate, and 57 is an adjustment screw.

Claims (1)

[Scope of utility model registration request] A movable contact that opens and closes when the handle is rotated, a fixed contact that comes into contact with and opens the movable contact of the movable contact, a latch mechanism that latches the contact state between the movable contact and the fixed contact, and a movable contact and the fixed contact. A bimetal that is inserted into a current-carrying path passing through a contact point, and when an overcurrent flows, heats up and deforms, pushing the free end against the contact piece of the latch mechanism in the direction of releasing the latch, thereby releasing the latch mechanism, and the release of the latch mechanism. In a circuit breaker equipped with a spring biasing mechanism that sometimes moves a movable contact in the opening direction, the bimetal is constructed of a long plate having a fixed end side and a free end side, and the free end side of the bimetal A side that is inclined with respect to the longitudinal direction is formed on the side, and a small-diameter female threaded hole is formed closer to this inclined side than the other sides, and an adjustment screw for adjusting the pushing condition of the abutting piece of the latch mechanism is inserted into this female threaded hole. A circuit breaker characterized by being screwed together so that it can be screwed freely.