JP2012038581A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker which performs neither reset operation not latch when a fixed contact point and a movable contact point are welded together.SOLUTION: A circuit breaker includes: a trip arm 6 locked at a latch piece 7, which is deformable with overcurrent or the like, to keep a closed state of a contact point; and a toggle link unit 4 having an upper toggle link 4a and a lower toggle link 4b. The end of the upper toggle link 4a is coupled with the trip arm 6 and the end of the lower toggle link 4b is coupled with a movable contact 2. When the latch piece 7 has deformed, the locking between the latch piece 7 and the trip arm 6 is released, thereby causing a trip operation, and in turn the toggle link unit 4 performs opening operation on the movable contact 2. After a trip operation occurs with a movable contact point 2a and a fixed contact point 3a welded together, if an operating handle 1 performs off operation, an engagement protrusion 19 in contact with a bracket 8 supporting the operating handle 1 appears at the upper toggle link 4a, thereby suppressing rotary movement of the trip arm 6 to prevent from being locked at the latch piece 7.

Description

  The present invention relates to a circuit breaker, and more particularly to a circuit breaker having a structure in which an operation handle cannot be turned off when a fixed contact and a movable contact are welded.

  If the fixed contact and the movable contact are welded and the contacts do not dissociate even if the shut-off operation is performed, if the operation handle is turned off so that it can be seen by appearance, it will return to the trip position or to the off position. There are some that are configured so that they cannot move. For example, in Patent Document 1, when the contacts are welded to each other, the crossbar connected to the movable contact does not rotate, and the handle lever (handle support bracket) configured to engage with the crossbar has a certain amount. Can no longer rotate. As a result, since the operation handle cannot move to the off position, the operator can recognize from the state of the operation handle that the contact has been welded.

JP 2007-265830 A

  However, even if the conventional circuit breaker operates in the contact-welded state, if the operation handle is turned off, the contact is not dissociated, but the latch is applied, and as a result, the operation to maintain the on-state is performed. It was.

  5 and 6 are side explanatory views showing the internal mechanism of such a conventional circuit breaker. FIG. 5 shows the case of normal operation, (a) shows the on state, (b) shows the trip state, FIG. 6 shows the case where the contacts are welded, (a) shows the trip state, and (b) shows the reset operation. Indicates the state. 5 and 6, 101 is an operation handle, 102 is a movable contact having a movable contact 102a, 103 is a fixed contact having a fixed contact 103a, 104a is an upper toggle link, 104b is a lower toggle link, and 105 is a movable contact. An arm member connected to the child 2, 106 is a trip arm, 107 is a latch piece, 108 is a handle support bracket to which the operation handle 101 is fixed, and 109 is a frame in which these members are assembled.

  FIG. 7A shows the upper toggle link 104a, and FIG. 7B shows the trip arm 106 extracted. The upper toggle link 104a is provided with an upper through hole 120 pivotally attached to the trip arm 106 and a lower through hole 121 pivotally attached to the lower toggle link 104b. The trip arm 106 is provided with an upper through hole 122 that is pivotally attached to the upper toggle link 104 a and a lower through hole 123 that is connected to the frame 109. Further, a protrusion 106 a for engaging with the handle support fitting 108 is formed in the vicinity of the upper through hole 122.

The conventional circuit breaker configured as described above is in a state shown in FIG. 6A when the breaking operation is performed with the contact portion composed of the movable contact 102a and the fixed contact 103a being welded. When the operation handle 101 is turned off (reset operation) in this state, the tip of the trip arm 106 is locked to the latch piece 107 as shown in FIG. 6B, and the latch is engaged. Specifically, the protrusion 106 a formed on the trip arm 106 abuts on the handle support fitting 108 while the operation handle 101 is turned off.
As a result, the rotation of the trip arm 106 is promoted, and the tip of the trip arm 106 is locked to the latch piece 107. For this reason, even if the contact portion is disengaged for some reason thereafter, the operation handle 101 does not shift to the trip state, and it cannot be recognized in the state of the operation handle 101.

  Therefore, in view of such a problem, the present invention is a circuit in which the reset contact does not operate even when the reset operation is performed and the latch does not occur in the state where the fixed contact and the movable contact are welded and connected when the disconnection operation is performed. The purpose is to provide a circuit breaker.

In order to solve the above-mentioned problem, the invention of claim 1 is directed to a contact portion comprising a movable contact and a fixed contact provided on an electric circuit, an operation handle for opening and closing the contact portion by an on / off operation, and an overcurrent. A latch piece that is displaced in response to the occurrence of the occurrence, a trip arm that is locked to the latch piece to maintain the closed state of the contact portion, an operation handle, and an opening / closing operation of the movable contact in cooperation with the trip arm A movable contact having an upper toggle link and a toggle link portion composed of a lower toggle link, the tip of the upper toggle link being connected to the trip arm, and the tip of the lower toggle link having the movable contact The toggle link part transmits the on / off operation of the operation handle to the movable contact to open and close the contact part, thereby generating an abnormal current such as an overcurrent. When the latch piece is displaced, the trip arm rotates and trips, and the toggle link unit interlocks to open the movable contact. In the circuit breaker that disables the display of the operation handle by the action of the toggle link portion, the movable contact and the fixed contact are connected even if the trip operation is performed. When the operation handle is turned off, the upper toggle link is provided with a first engagement protrusion that abuts on a handle support fitting that supports the operation handle, and the operation of the trip arm is performed by this contact action. Is restricted and is not locked to the latch piece.
According to this configuration, when the trip is performed due to the occurrence of overcurrent, etc., the movable contact and the fixed contact are welded and the movable contact does not disengage, even if the operation handle is reset, the upper toggle link The first engagement protrusion provided on the handle abuts on the handle support bracket, so that the trip arm is restricted from being engaged with the latch piece. Therefore, the reset operation is not performed even if the operation handle is reset.
Therefore, when the connection state of the contacts is subsequently released and dissociated, the original trip state is entered and resetting is possible, and the return to the normal state can be recognized without checking the inside.

According to a second aspect of the present invention, in the configuration according to the first aspect, when the movable contact and the fixed contact are disengaged due to a trip operation, the operation handle is turned off to support the operation handle. The upper toggle link is provided with a second engagement protrusion that contacts the handle support bracket, and the contact arm rotates to the angle at which the trip arm engages the latch piece. It is characterized by locking.
According to this configuration, in a normal operation state of the circuit breaker in which the contact is disengaged due to the trip operation, the reset operation is performed by the second engagement protrusion provided on the upper toggle link being engaged with the handle support fitting. Therefore, it is not necessary to provide a separate protrusion on the trip arm.

  According to the present invention, when a trip is performed due to occurrence of an overcurrent or the like, if the movable contact and the fixed contact are welded and the movable contact does not disengage, the reset operation is not performed even if the operation handle is reset. . Therefore, when the connection state of the contacts is subsequently released and dissociated, it is possible to reset to the original trip state and to recognize the return to the normal state without checking the inside.

It is side surface explanatory drawing of the internal mechanism which shows an example of the circuit breaker which concerns on this invention, (a) is an ON state, (b) has shown the trip state. It is side surface explanatory drawing of the internal mechanism at the time of a contact welding in the circuit breaker of FIG. 1, (a) is a trip state, (b) has shown the reset operation state. The main part member in the internal mechanism of FIG. 1 is shown, (a) is an upper toggle link, (b) is a trip arm. It is explanatory drawing which shows the relationship between an operation handle and an internal mechanism, (a) is the state at the time of ON, (b) has shown the state at the time of reset operation. It is side surface explanatory drawing of the internal mechanism of the conventional circuit breaker, (a) is an ON state, (b) has shown the trip state. It is side surface explanatory drawing of an internal mechanism at the time of a contact welding in the circuit breaker of FIG. 5, (a) is a trip state, (b) has shown the reset operation state. FIG. 6 shows main members in the internal mechanism of FIG. 5, (a) is an upper toggle link, and (b) is a trip arm.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. 1 and 2 show an example of a circuit breaker according to the present invention, and show a side view of an internal mechanism. FIG. 1 (a) shows an on state, FIG. 1 (b) shows a trip state, FIG. 2 (a) shows a trip state when the contact is welded, and FIG. 2 (b) shows a reset state when the contact is welded. Yes.
1 and 2, 1 is an operation handle for turning on / off, 2 is a movable contact having a movable contact 2a, 3 is a fixed contact having a fixed contact 3a, 4a is an upper toggle link, 4b is a lower toggle link, 5 is an arm member to which the movable contact 2 is assembled, 6 is a trip arm for interrupting the contact, 7 is a latch piece that is displaced by the occurrence of an abnormal current such as an overcurrent, 8 is A handle support metal fitting 9 to which the operation handle 1 is fixed is a frame that is fixed to a circuit breaker case (not shown) and that assembles these members.

The movable contact 2a and the fixed contact 3a constitute a contact portion that opens and closes the electric circuit. The movable contact 2 is arranged on the load side of the electric circuit, and the fixed contact 3 is arranged on the power source side of the electric circuit. Hereinafter, the power supply side will be described as the front and the load side will be described as the rear.
The operation handle support bracket 8 has a shaft support portion 8a that is pivotally supported by the frame 5 at the lower end. The operation handle support fitting 8 can be rotated in the front-rear direction around the shaft support portion 8a. It is comprised so that it may rotate to turn off an electric circuit.

3A shows the upper toggle link 4a, and FIG. 3B shows the trip arm 6 extracted. The upper toggle link 4a is formed in a long plate shape, the upper through hole 20 is a shaft attachment portion that is axially attached to the trip arm 6, and the lower through hole 21 is a connection portion for connection to the lower toggle link 4b. Further, an engaging projection 19 is formed on the upper end. The engaging protrusion 19 includes a corner portion 19a that contacts the handle support bracket 8 under specific conditions and a contact side 19b formed on the side portion.
The lower toggle link 4b (not shown) is also formed in a long plate shape like the upper toggle link 4a. The upper toggle link 4b has a connecting part connected to the upper toggle link at the upper part, and the lower part is attached to the arm member 5 at the lower part. It has a part 5a. Thus, the upper toggle link 4a and the lower toggle link 4b are rotatably connected to each other via the connecting shaft 12 (shown in FIG. 1) to form the toggle link portion 4.

On the other hand, as shown in FIG. 3B, the trip arm 6 is a plate body formed in a substantially square shape, and the through hole 22 formed in the upper portion is a shaft attachment portion and a lower portion that are axially attached to the upper toggle link 4a. The through-hole 23 formed in is a shaft-attached portion that is pivotally attached to the frame 9. A claw portion 6a that engages with the latch piece 7 is formed at the rear.
Thus, the upper part of the upper toggle link 4 a is connected to the trip arm 6, the lower end of the lower toggle link 4 b is connected to the arm member 5, and the trip arm 6 is rotated so that the movable contactor is connected via the toggle link part 4. 2 is configured to rotate.

FIGS. 4A and 4B are side explanatory views of the internal mechanism for explaining the relationship between the handle support bracket 8 and the toggle link portion 4, wherein FIG. 4A shows a state at the time of ON and FIG. 4B shows a state at the time of a reset operation. . In FIG. 4, reference numeral 13 denotes a coil spring disposed between the handle support fitting 8 and the connecting shaft 12. Due to the contraction force of the coil spring 13, the connecting shaft 12 is constantly biased in the direction of the operation handle 1 (upward), and the connecting shaft 12 that becomes the center of the toggle link portion 4 depending on the ON / OFF angle of the operation handle 1. The urging direction changes from diagonally forward to diagonally upward.
As a result, the toggle link portion 4, the trip arm 6, and the arm member 5 are changed by turning on / off the operation handle.

Next, the operation of the circuit breaker including the internal mechanism configured as described above will be described. First, normal operation in which the contacts are not welded will be described.
In the circuit breaker-off state, the operation handle 1 that is tilted rearward is turned forward to be turned on as shown in FIG. By this operation, the movable contact 2 in the open state is inverted, the movable contact 2a contacts the fixed contact 3a, and the circuit breaker is turned on.
Specifically, the direction of pulling by the coil spring 13 changes from obliquely upward to obliquely forward by turning the operation handle 1. Therefore, since the connecting shaft 12 of the toggle link part 4 tends to move forward, the toggle link part 4 extends. As a result, the movable contact 2 is biased in a tilting direction, and the contacts 2a and 3a are connected to each other. At this time, the state where the trip arm 6 is locked to the latch piece 7, that is, the state where the latch is applied, is maintained, and the ON state is maintained by the pulling force of the coil spring 13 even if the operation handle 1 is released. Thus, the electric circuit is turned on.

  When the circuit breaker is off, the circuit is in the same state as the reset state shown in FIG. In this state, the trip arm 6 is in a state of being latched to the latch piece 7 (latched state), and the pulling by the coil spring 13 is obliquely upward to the upper toggle link 4a and acts to lift the lower toggle link 4b. As a result, the movable contact 2 rises and opens, and the state is maintained.

  When the circuit breaker is on, tripping occurs when a short-circuit current or overcurrent flows. Specifically, when an overcurrent detection unit (not shown) detects an overcurrent, or when the short circuit current detection unit detects a short circuit current, the latch piece 7 is displaced. As a result, the claw portion 6a of the trip arm 6 is disengaged from the latch piece 7 (the latch is released), the trip arm 6 is rotated by the pulling force of the coil spring 13, and the state shifts to the state shown in FIG. To do. As a result, the movable contact 2 is pulled upward by the action of the toggle link portion 4 and pivoted in the opening direction, thereby interrupting the electric circuit. That is, the circuit breaker trips.

Since this trip state is a state in which the latch is released, even if the operation handle 1 is turned on, the operation is not transmitted to the toggle link unit 4 and the on operation is not performed. Conversely, the reset operation is performed by performing an off operation (reset operation) for rotating the operation handle 1 backward. That is, the state shown in FIG.
Specifically, the corner 19a of the engagement protrusion 19 formed on the upper toggle link 4a is formed on the handle support bracket 8 while the operation handle 1 is rotated by the reset operation of rotating the operation handle backward. Engage with the engaging surface 8b. Due to this contact action, the upper toggle link 4a moves in conjunction with the subsequent turning operation of the operation handle 1 to the rear. As a result, the trip arm 6 rotates and finally the claw portion 6a is locked to the lower end of the trip piece 7 to be in a latched state. In this way, the state shown in FIG. 4B is obtained, and even if the operation handle 1 is freed thereafter, the off state is maintained without moving forward. Thereafter, when the ON operation is performed, the electric circuit is turned ON again as described above.

Next, the operation when the contacts are welded will be described. In the ON state in which the operation handle 1 is rotated forward, when the electric circuit current exceeds the rating and an overcurrent flows or a short-circuit current flows, a trip operation is performed as described above. However, when the movable contact 2a and the fixed contact 3a are welded and connected during this trip, the state shown in FIG. That is, although the latch is released, the movable contact 2 does not stand up and the contacts are kept in contact with each other.
In this case, since the movable contact 2 does not open even if the trip operation is performed, the state of the toggle link portion 4 hardly changes and maintains a substantially straight state. Therefore, the trip arm 6 connected to the toggle link portion 4 does not rotate greatly. Since this trip state is in a state in which the latch is released, even if the operation handle 1 is turned on, the toggle link portion 4 is not interlocked and does not turn on.

  Further, even if an off operation (reset operation) for rotating the operation handle 1 backward from this state is performed, the reset state as shown in FIG. Specifically, during the turning-off operation of the operation handle 1, the handle support fitting 8 engages with the engagement protrusion 19 formed on the upper toggle link 4a as in the normal off-operation described above. However, at this time, since the toggle link portion 4 is maintained in a substantially straight state, the contact side 19b, not the corner portion 19a of the engagement protrusion 19, abuts on the engagement surface 8b of the handle support bracket 8 to be engaged. To do.

  Due to this contact action, the operation of the trip arm 6 is restricted, and even if the operation handle 1 is rotated to the rear limit, the trip arm 6 is not rotated to an angle at which the trip arm 6 is locked to the trip piece 7. As a result, the reset operation is not performed and the state shown in FIG. Then, when the rotation of the operation handle 1 is stopped and the operation handle 1 is made free, the connecting shaft 12 of the toggle link portion 4 is arranged in front of the shaft support portion 8a of the handle support bracket 8, so that the coil spring 13 The operating handle 1 moves back (on direction) by the urging force and returns to the trip state shown in FIG.

As described above, when the movable contact 2a and the fixed contact 3a are welded and the movable contact 2 does not disengage when the trip operation is performed due to the occurrence of an overcurrent or the like, even if the operation handle 1 is reset, Since the operation of the trip arm 6 is restricted when the contact side 19b of the engagement projection 19 provided on the upper toggle link 4a contacts the handle support fitting 8, the latch piece 7 is not engaged. Therefore, even if the operation handle 1 is reset, no reset operation is performed.
Therefore, when the connection state of the contacts is subsequently released and dissociated, it is possible to reset to the original trip state and to recognize the return to the normal state without checking the inside.
Further, in a normal operation state of the circuit breaker in which the contacts are disengaged by tripping, the corner 19a of the engaging projection 19 provided on the upper toggle link 4a is engaged with the handle support fitting 8 so that the reset operation is performed. The trip arm 6 does not need to be provided with a protrusion that engages with the handle support fitting 8 separately.

  In the above embodiment, when the reset operation is performed with the contacts 2a and 3a welded together, the contact side 19b of the engagement protrusion 19 is brought into contact with the handle support bracket 8, but the shape of the contacted portion is Similar to the corner 19a, it may be a simple protrusion, and its shape is arbitrary.

  1 .... Operation handle, 2 .... movable contact, 2a .... movable contact, 3 .... fixed contact, 3a fixed contact, 4 .... toggle link part, 4a ... upper toggle link, 4b ... lower toggle link 6. Trip arm 6 a. Claw 7. Latch piece 8 Handle handle bracket 19 Engagement projection 19 a Corner (second engagement projection) 19 b Contact side (first engagement protrusion).

Claims (2)

A contact portion comprising a movable contact and a fixed contact provided on the electric circuit; an operation handle for opening and closing the contact portion by an on / off operation; a latch piece that is displaced upon occurrence of an overcurrent; and the latch piece A trip arm that is locked to the contact portion and maintains the closed state of the contact portion, and a toggle link portion that includes an upper toggle link and a lower toggle link that opens and closes the movable contact in cooperation with the operation handle and the trip arm. Have
The tip of the upper toggle link is connected to the trip arm, while the tip of the lower toggle link is connected to a movable contact provided with the movable contact, and the toggle link portion performs on / off operation of the operation handle. Transmitting to the movable contact to open and close the contact point,
When the latch piece is displaced in response to the occurrence of an abnormal current such as an overcurrent, the trip arm rotates to perform a trip operation, and the toggle link unit interlocks to open the movable contact, while a trip operation is performed. When the movable contact and the fixed contact are welded and connected, in the circuit breaker that disables the operation handle off display by the action of the toggle link portion,
When the movable contact and the fixed contact are connected even when a trip operation is performed, the first engagement protrusion that contacts the handle support metal fitting that supports the operation handle in response to the off operation of the operation handle is received. Provided in the upper toggle link,
The circuit breaker characterized in that the operation of the trip arm is restricted by this contact action and is not locked to the latch piece. When the movable contact and the fixed contact are separated from each other due to a trip operation, the second engagement protrusion that contacts the handle support metal fitting that supports the operation handle in response to the off operation of the operation handle is formed on the upper toggle. Provided in the link,
2. The circuit breaker according to claim 1, wherein the contact arm rotates to an angle at which the trip arm engages with the latch piece, and the trip arm is locked to the latch piece.

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