JP3246588B2 - Arc gas discharge device of circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for discharging arc gas from a circuit breaker in a circuit breaker such as a wiring circuit breaker or an earth leakage circuit breaker, and more particularly, to a protective plate for closing an exhaust port through which an arc gas passes. Regarding improvement.

[0002]

2. Description of the Related Art FIG. 4 is a longitudinal sectional view of a three-pole circuit breaker to which an arc gas discharging device according to the present invention is applied. In the figure, an insulating container consisting of a molded resin case 1 and a cover 2 has three cut-off chambers extending from a power supply side (left end side in the figure) to a load side (right end side in the figure).
Are formed in parallel with each other, and a shut-off section including a fixed contact 3 and a movable contact 4 is accommodated in a cut-off chamber (center pole in the drawing) of each pole. The fixed contact 3 integral with the power supply terminal 5 is fixed to the case 1, and the movable contact 4 rotatably supported by the case 1 via an insulating holder 6 is opened and closed at the center pole shown in the figure. It is opened and closed by the mechanism 7. An arc-extinguishing chamber having a multi-stage grid 8 is arranged so as to surround the blocking section.

In the illustrated closed state, current flows from the power source terminal 5 through the fixed contact 3, the movable contact 4, the flexible conductor 9, the heater 11 of the overcurrent trip device 10, the relay conductor 12, and the load side. It flows to terminal 13. Although the detailed description is omitted, the energizing current becomes an overcurrent state and the overcurrent trip device 10
Is activated, the latch 14 of the opening / closing mechanism 7 is unlocked,
The movable contact 4 is driven clockwise in the figure by the spring force accumulated in the opening / closing spring 15 to interrupt the current.
At that time, an arc is generated in the interruption portion, and this arc is drawn into the grid 8 of the arc extinguishing chamber and extinguished. At the same time, the heat of the arc heats the air in the shutoff chamber and surrounding insulators to generate arc gas, and this arc gas is ejected to the outside from the openings 16 at both ends (power supply side and load side) of the shutoff chamber.

[0004] Here, the opening 16 of the shielding chamber is covered with a shielding plate 17 so that foreign matter such as electric wire debris does not enter the shielding chamber from this portion. The shield plate 17 is provided with an exhaust port for discharging the arc gas. However, the shield plate 1 is designed to prevent foreign matter from entering through the exhaust port.
A protection plate 18 for closing the exhaust port is superposed on the front surface of 7. FIG. 5 is an enlarged front view showing the opening 16 to which the shielding plate 17 and the protection plate 18 are attached. In the figure, but blocking chamber opening 16 is straddling on the casing 1 and the cover 2, the case 1 is provided respectively perpendicular groove 19 in the lateral edges facing the opening 16, the lower half of FIG. The convex shielding plate 17 having a width larger than that of the upper half is fixed by inserting the left and right edges of the lower half into the grooves 19. The upper half of the shielding plate 17 is in close contact with the periphery of the cover 2 facing the opening 16, and a rectangular exhaust port 20 for discharging arc gas is provided in this portion.
In the case shown in the figure, three pieces are provided in two rows on the left and right, and a total of six pieces are provided.

On the other hand, similarly to the shielding plate 17, the protection plate 1 having a convex shape is used.
8 has one end (upper end in the figure) as a free end and the other end (lower end in the figure) as a fixed end, and mounting pieces 18 a protruding on both left and right sides of the fixed end are inserted into the groove 19 together with the shielding plate 17. And the free end thereof closes the exhaust port 20 of the shielding plate 17. The shielding plate 17 and the protection plate 18 are both made of a material such as a bakelite plate or a polyester glass mat laminated plate. The thickness of the shielding plate 17 is about 1 mm, whereas the protection plate 18 is elastic. Made less than half of it for easy deformation. When the arc gas is discharged, the free end of the protection plate 18 is elastically deformed by the gas pressure toward the load side in FIG. 4 as indicated by the dashed line, and the exhaust port 20 is opened to discharge the arc gas. That is, the free end of the protection plate 18 has a function of a valve for opening and closing the exhaust port 20.

[0006]

In the conventional configuration shown in FIG. 5, in the case of a circuit breaker having a high breaking capacity, in order to increase the area of the exhaust port 20 in response to an increase in the amount of discharge of arc gas, this portion is required. the height H ₁ of the free end of the protective plate 18 that overlaps as large as possible, that amount, it is necessary to reduce the height H ₂ of the fixed end. However, the height of the fixed end, that is, when the attachment piece 18a of the height H ₂ is too small, since the hooking amount for the grooves 19 of the protective plate 18 is reduced, the risk of the protective plate 18 will be scattered by the pressure of the arc gas Occurs. Further, when the height H ₂ is reduced, a gap H ₃ from the upper end surface of the mounting piece 18a until the mating surfaces of the case 1 cover 2 becomes larger, the positional deviation protective plate 18 upward in the drawing within the range In this case, there is also a danger that the closed exhaust port 20 is exposed. The present invention addresses such issues,
It is an object of the present invention to provide an arc gas discharge device for a circuit breaker having an enhanced arc gas discharge effect while effectively preventing the protection plate from scattering and displacing.

[0007]

In order to achieve the above object, the present invention covers an opening of a shut-off chamber formed in an insulating container comprising a case and a cover, and exhausts arc gas from the opening. A shielding plate having an opening, and a protective plate having an elasticity which is superposed on the front surface of the shielding plate and closes the exhaust port. The protective plate has one end as a free end, the other end as a fixed end, and the fixed end. In the arc gas discharge device of the circuit breaker, the mounting pieces projecting to the left and right sides of the circuit breaker are fixed by being inserted into the grooves of the case, and when discharging the arc gas, the free end is elastically deformed to open the exhaust port. to the mounting piece, Rutotomoni provided the formed slit cut along the side of the free end of the protective plate, before
Protrusions are provided on the left and right sides of the free end of the protective plate.
It is to be inserted into the groove formed in the cover.

[0008]

[Function] By providing a slit formed by cutting along the side surface of the free end of the protective plate, the height of the free end is reduced by the depth of the slit without reducing the height of the mounting plate. Can be increased. Also,
In that case, the protrusion provided on the left and right sides of the free end of the protective plate, and inserted into a groove formed the protrusion on the cover, normally by engaging the free end to the cover via the protrusion, free It is possible to prevent the protection plate from falling forward due to an increase in the height of the end.

[0009]

1 to 3 show an embodiment of the present invention. FIG. 1 is a front view of an opening portion of a shut-off chamber, FIG. 2 is a front view of a protective plate in FIG. 1, and FIG. It is a front view. Note that the same reference numerals are used for the portions corresponding to the conventional example. In the figure, the protection plate 18 is fixed by inserting the mounting pieces 18a projecting to the left and right sides of the fixed end into the grooves 19 of the case 1 with the upper end in the figure as a free end and the lower end as a fixed end. The mounting piece 18a has a slit 21 cut along the side surface of the free end of the protection plate 18 to a depth D. Further, projecting pieces 18b are provided on both left and right sides of the free end of the protection plate 18, and the projecting pieces 18b are inserted into grooves 22 provided vertically on the left and right edges facing the opening 16 of the cover 2. On the other hand, the shape of the shielding plate 17 is the same as that of the conventional one, but the exhaust ports 20 are arranged in a row to a position higher and lower than the conventional one so as to correspond to high breaking capacity.

The protection plate 18 in which the slit 21 is cut into the mounting piece 18a is elastically deformed from the bottom of the slit 21 when receiving the gas pressure of the arc gas, and opens the exhaust port 20. In other words, the height of the free end is (H ₁ + D) regardless of the height H ₂ of the fixed end.
Can be expanded to: Therefore, the height of the free end which acts as a valve is increased while securing the height H ₂ of the fixed end to ensure sufficient fixing so as not to be easily scattered by gas pressure, and to exhaust the shielding plate 17 as shown in the figure. The port 20 can be arranged at a position lower than the conventional one, and the area of the exhaust port can be enlarged. Moreover, because it can increase the height H ₂ of the fixed end,
Since the gap H ₃ from the upper end surface of the mounting piece 18a until the mating surfaces of the case 1 cover 2 can be reduced, with respect to the height H ₄ from the bottom surface to the lower edge of the least significant of the exhaust port 20 of the shield 17 H ₃ <H ₄ to prevent the exhaust port 20 from being exposed even if the protective plate 18 is displaced upward. Further, even more likely to occur is leaning in the forward protective plate 18 since the height of the free end increases, the protrusion 18b is formed as the free end of the illustrated grooves the projecting piece 18b of the cover 2 22 by inserting the above tilting is eliminated.

[0011]

According to the present invention, since the height of the free end that acts as a valve can be increased even if the height of the mounting piece of the protection plate is increased, the protection plate can be fixed in a circuit breaker having a high breaking capacity. It is possible to increase the area of the exhaust port of the shielding plate while ensuring the above, and to prevent the exhaust port from being exposed due to the displacement of the protective plate. In this case, since the protruding piece formed at the free end of the protection plate is inserted into the groove of the cover, the protection plate does not fall forward due to an increase in the height of the free end.

[Brief description of the drawings]

FIG. 1 is a front view of an opening of an interrupting chamber of a circuit breaker according to an embodiment of the present invention.

FIG. 2 is a front view of the protection plate in FIG.

FIG. 3 is a front view of the shielding plate in FIG. 1;

FIG. 4 is a longitudinal sectional view of a circuit breaker to which the present invention is applied.

FIG. 5 is a front view of an opening of an interrupting chamber of a circuit breaker showing a conventional configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Cover 3 Movable contact 4 Fixed contact 7 Opening / closing mechanism 16 Shielding room opening 17 Shielding plate 17a Mounting piece 17b Projection piece 18 Protective plate 19 Case groove 20 Exhaust port 21 Slit 22 Cover groove

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-18783 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 73/18 H01H 73/06

Claims (1)

(57) [Claims] 1. A shielding plate, which covers an opening of a shielding chamber formed in an insulating container formed of a case and a cover, and has an exhaust port for discharging arc gas from the opening, and is placed on a front surface of the shielding plate. A protective plate having elasticity for closing the exhaust port.The protective plate has one end as a free end and the other end as a fixed end, and mounting pieces projecting on both left and right sides of the fixed end are inserted into grooves of the case. Fixed by
When discharging the arc gas, in the arc gas discharge device of the circuit breaker in which the free end is elastically deformed to open the exhaust port, a slit formed by cutting along a side surface of the free end of the protection plate is formed in a mounting piece of the protection plate. provided Rutotomoni, said
Protrusions are provided on the left and right sides of the free end of the protection plate, and these
An arc gas discharge device for a circuit breaker, wherein the device is inserted into a groove formed in the cover .