JP5268794B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker that detects that an overcurrent has flowed in a circuit by bimetal, and causes a mechanical unit to perform a tripping operation to interrupt the circuit.

  Bimetal for overcurrent detection is built in the circuit breaker and earth leakage circuit breaker, and when the overcurrent flows, the bimetal generates heat and bends, causing the mechanism to trip and shut off the circuit. It is supposed to be. Specifically, when the bimetal is bent, the trigger lever is pushed and rotated, the trigger lever rotates the engaging member to release the engagement with the latch, and the mechanism part is pulled out to perform a general operation. . (Patent Document 1)

  FIG. 8 is a diagram showing the relationship between a conventional trigger lever and a trigger hook which is an engaging member, 11 is a trigger lever supported by a shaft 16, 9 is a trigger hook which is an engaging member, and 7 is a latch. . The trigger lever 11 is provided with a protrusion 14 that contacts the trigger hook 9. When the trigger lever 11 is pushed in the direction of the arrow by the bimetal, the trigger lever 11 rotates counterclockwise toward the trigger hook 9. The action point P at the tip of 14 pushes the trigger hook 9, and the trigger hook 3 rotates clockwise about the shaft 10 to disengage the latch 7.

  However, since the point of action P at the tip of the protrusion 14 is one point in the past, even after the trigger lever 11 starts to rotate due to bimetal, the axis 16 and the point of action as the rotation center of the trigger lever 11 as shown in FIG. The distance from P is constant. Therefore, until the engagement between the trigger hook 9 and the latch 7 is disengaged, the bimetal needs to keep pushing the trigger lever 11 for a long time. For this reason, there has been a problem that the amount of bending required for the bimetal is increased, and the interruption time becomes longer. Further, as the trigger lever 11 rotates, the trigger hook 9 and the action point P at the tip of the projection 14 are pushed while being rubbed, so that there is a problem that a transmission loss of rotational force to the trigger hook 9 occurs.

JP 2006-236874 A

  The present invention solves the above-described conventional problems, makes it possible to make the rotation angle of the trigger lever by the bimetal necessary for performing the tripping operation smaller than that of the conventional one, and the rotational force from the trigger lever to the engaging member. An object of the present invention is to provide a circuit breaker with reduced transmission loss.

  The present invention, which has been made to solve the above-mentioned problems, includes a trigger lever that is rotated by being pushed by a bimetal, and an engagement member that is rotated by being pushed by the trigger lever and causes a tripping operation. In this device, the trigger lever contacts with the engaging member at two or more points.

In the present invention, the point of action is a plurality of independent points that sequentially contact the engaging member as the trigger lever rotates, or the point of action sequentially contacts the engaging member as the trigger lever rotates. Embodiments that are continuous points can be taken. Further, the engaging member can be composed of a trigger hook and a latch, and in this case, it is preferable that the rotation directions of the trigger lever and the latch are opposite to each other.

  If the circuit breaker of the present invention has only one point of action, the contact angle changes as it rotates, and the point of action is pushed while rubbing the surface of the engaging member diagonally, so that the rotational force is transmitted. Although a loss occurs, the distance between the axis that is the rotation center of the trigger lever and the action point is increased as the trigger lever rotates by setting the action point where the trigger lever contacts the engaging member to two or more points. The engagement member can be rotated by a necessary amount even if the rotation angle of the trigger lever is made smaller than that of the prior art. Further, by changing the position of the action point, the change in the contact angle accompanying the rotation of the trigger lever can be suppressed, so that the transmission loss of the rotational force from the trigger lever to the engaging member is also reduced. That is, the engagement member can be rotated by a necessary amount even if the rotation angle of the trigger lever is made smaller than before.

It is a whole perspective view of the circuit breaker of an embodiment. It is the center longitudinal cross-sectional view which abbreviate | omitted the cover of the circuit breaker of embodiment. It is a perspective view of a trigger lever. It is an enlarged view of the principal part. It is an enlarged view of the principal part. It is an enlarged view of the principal part which shows other embodiment. It is an enlarged view of the principal part which shows other embodiment. It is explanatory drawing of a prior art. It is explanatory drawing of a prior art.

Embodiments of the present invention will be described below.
FIG. 1 is an overall perspective view of a circuit breaker according to an embodiment, and FIG. 2 is a central longitudinal sectional view with a cover omitted. In these drawings, 1 is a power supply side terminal plate, 2 is a movable contact, 3 is a cross bar for holding the movable contact 2, 4 is a handle, and 5 is a mechanism for interlocking the handle 4 and the cross bar 3. . Reference numeral 6 denotes a cradle which is a part of the mechanism portion 5, and its tip is engaged with a hole of the latch 7.

  The latch 7 is pivotally supported by a lower shaft 8 and is repelled clockwise by a spring force (not shown). However, in the ON state, the upper end of the latch 7 is in contact with the tip of the trigger hook 9, and the position is maintained. The trigger hook 9 is pivotally supported by a shaft 10 at a substantially central portion, and the lower portion extends obliquely toward the load side. A trigger lever 11 supported by a shaft 16 is disposed on the load side of the trigger hook 9, and a bimetal 12 is disposed on the load side. In this specification, the latch 7 and the trigger hook 9 are called engagement members.

  The bimetal 12 is always at a position slightly away from the trigger lever 11, but is bent when an overcurrent flows through the circuit, and the adjustment screw 13 at the upper end rotates the trigger lever 11 counterclockwise. As a result, the lower portion of the trigger hook 9 is pushed to rotate the trigger hook 9 in the clockwise direction, the engagement with the upper end of the latch 7 is released, and the latch 7 is caused to perform a trip operation. The above configuration is not particularly different from the conventional circuit breaker. However, in the present invention, the structure of the trigger lever 11 is different from the conventional one, and will be described in detail below.

FIG. 3 is a perspective view of the trigger lever 11 in the present embodiment, and FIGS. 4 and 5 are enlarged side views showing the relationship between the trigger lever 11 and the trigger hook 9. As shown in the drawing, the trigger lever 11 is formed with a protrusion 14 for pressing the trigger hook 9. The side surface is not parallel to the lower part of the trigger hook 9 but has a slightly vertical angle. For this reason, as shown in FIG. 4, in the normal state, the lower end of the protrusion 14 serves as an action point P <b> 1 where the trigger hook 9 comes into contact. However, as shown in FIG. 5, when the trigger lever 11 rotates counterclockwise about the shaft 16, the upper end of the protrusion 14 becomes an action point P <b> 2 that contacts the trigger hook 9. That is, in this embodiment, as the trigger lever 11 rotates, it has a plurality of independent action points P1 and P2 that sequentially contact the trigger hook 9.

  Therefore, when the trigger lever 11 starts to rotate counterclockwise around the shaft 16 from the normal state shown in FIG. 4 and is pushed by the bimetal 12, the trigger hook 9 is first pushed by the lower action point P1. At this time, since the distance between the axis 16 of the trigger lever 11 and the lower action point P1 is short and the distance between the axis 10 of the trigger hook 9 and the action point P2 is long, the trigger hook 9 can be pushed strongly.

  However, when the trigger lever 11 is further rotated by being pushed by the bimetal 12, the trigger hook 9 is pushed by the upper action point P2 as shown in FIG. At this time, the distance between the axis 16 of the trigger lever 11 and the upper action point P2 is longer than that in FIG. 4, and the distance between the axis 10 of the trigger hook 9 and the upper action point P2 is shorter than that in FIG. The trigger hook 9 can be pushed earlier.

  As described above, according to the present invention, the force for pushing the trigger hook 9 can be strengthened at first, and the speed at which the trigger hook 9 is rotated can be increased after starting to move. This is because a static frictional force acting when trying to move the stationary trigger hook 9 requires a larger force to move the trigger hook 9, and the trigger hook 9 does not move unless the force exceeds a certain limit value. However, since the distance between the axis 10 of the trigger hook 9 and the action point P1 is long, a large force can be generated and the trigger hook 9 can start to move. After the trigger hook 9 continues to be pushed and moved, it can be operated with a weaker force than when it is stationary, and the distance between the axis 10 of the trigger hook 9 and the action point P2 is short, so the moving distance per unit time is increased even with a weak force. Is something that can be done. For this reason, the rotation angle of the trigger lever 11 by the bimetal 12 required to start the tripping operation can be made smaller than in the prior art. In addition, if only the lower action point P1 is reached, the contact angle changes as it rotates, and the action point P pushes while obliquely rubbing the surface of the trigger hook 9, causing a transmission loss of rotational force. According to the present invention, when the rotation proceeds, the upper action point P2 pushes the surface of the trigger hook 9, so that the transmission loss of the rotational force is reduced.

  In the above-described embodiment, the shape of the protrusion 14 of the trigger lever 11 is square and the two action points P1 and P2 are formed. However, the shape of the protrusion 14 of the trigger lever 11 is an arc as shown in FIG. You can also. In this case, the action point P becomes a continuous point that sequentially comes into contact with the trigger hook 9 as the trigger lever 11 rotates, but the above-described effects are almost the same. Further, as shown in FIG. 7, a small protrusion 15 may be formed on the trigger hook 9 side that contacts the protrusion 14 of the trigger lever 11, and a plurality of action points P may be generated as the trigger lever 11 rotates. .

  The arrangement of the trigger hook 9 is not limited to the embodiment, and the shaft 10 of the trigger hook 9 may be positioned below the protrusion 14 of the trigger lever 11. In that case, the rotation directions of the trigger hook 9 and the trigger lever 11 are the same. It is also possible to omit the trigger hook 9 and use only the latch 7 as the engaging member. In this case, the trigger hook 9 described above may be read as the latch 7. However, the bending amount of the bimetal 12 needs to be increased. Conversely, a design in which the number of trigger hooks 9 and trigger levers 11 is increased is possible, and in this case, the amount of bending of the bimetal 12 can be further reduced.

As described above, according to the present invention, the bimetal 1 necessary for performing the tripping operation.
The rotation angle of the trigger lever 11 by 2 can be made smaller than before, and the transmission loss of the rotational force from the trigger lever 11 to the engaging member can be reduced.

DESCRIPTION OF SYMBOLS 1 Power supply side terminal board 2 Movable contact 3 Crossbar 4 Handle 5 Mechanism part 6 Cradle 7 Latch 8 Latch axis 9 Trigger hook 10 Trigger hook axis 11 Trigger lever 12 Bimetal 13 Adjustment screw 14 Protrusion 15 Small protrusion 16 Trigger lever Axis P, P1, P2 Action point

Claims (5)

  In a circuit breaker including a trigger lever that is rotated by being pushed by a bimetal and an engagement member that is rotated by being pushed by the trigger lever and causes a tripping operation, an action point at which the trigger lever contacts the engagement member A circuit breaker characterized by having two or more points.   2. The circuit breaker according to claim 1, wherein the action points are independent plural points that sequentially come into contact with the engaging member as the trigger lever rotates.   2. The circuit breaker according to claim 1, wherein the operating point is a continuous point that sequentially contacts the engaging member as the trigger lever rotates.   2. The circuit breaker according to claim 1, wherein the engaging member includes a trigger hook and a latch.   The circuit breaker according to claim 4, wherein the rotation directions of the trigger lever and the latch are opposite to each other.

Images