JP4857881B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker for wiring breakers, earth leakage breakers, and the like, and more particularly to the structure of a circuit breaker switching mechanism.

  In the circuit breaker described above, if the main circuit contact is closed and the fixed contact and the movable contact are welded due to abnormal pulse current, etc., the overcurrent trip device operates normally. However, the latch of the opening / closing mechanism is released with the main circuit contact closed, and the operation handle moves from the ON position to the TRIP display position and stops.

  In this case, if it is possible to move the handle to the OFF position with the contacts welded, it is mistaken that the main circuit contact of the circuit breaker has been opened, and if maintenance or inspection of the load side circuit is performed in this state, There is a risk that an operator may get an electric shock by touching the live wire.

  Therefore, as a safety measure against the above problems, circuit breakers equipped with various types of isolation functions that mechanically lock the contacts so that they are prevented from moving to the OFF position when the contacts are welded during energization are conventionally used. As an example, the opening / closing mechanism is provided with a stopper mechanism that prevents the handle from moving to the OFF position when the contact is welded. If it is mild, the handle is released to release the latch to forcibly trip the open / close mechanism, and the circuit between the contacts is peeled off using the spring force of the open / close spring released by the trip operation. A circuit breaker is known (see Patent Document 1).

  Next, the structure of the circuit breaker disclosed by patent document 1 and each operation state are shown in FIGS. In each figure, 1 is a main body case of a circuit breaker, 2 is a stationary contact of a main circuit, 2a is a stationary contact, 3 is a movable contact held by a rotary contact holder 4, 3a is a movable contact, An arc extinguishing grid, 6 is an opening / closing mechanism connected to the contact holder 4, and 7 is an operation handle. Although not shown in the figure, the case 1 detects an overcurrent of the main circuit and gives a trip command to the opening / closing mechanism 6. It is equipped with a type or electromagnetic overcurrent trip device.

  Here, as shown in FIG. 9, the opening / closing mechanism 6 has a handle lever 8 whose tip (lower end in the figure) is pivotally supported by the frame 6 a and whose upper end is coupled to the operation handle 7, and one end pivotally supported by the support shaft 9. Then, the upper link 12 and the lower link 13 are connected to each other by connecting the swing link type latch 11 with the claw portion at the other end locked to the latch receiver 10 and the upper link 12 and the lower link 13 by the toggle pin 14. Opening and closing springs that are stretched between the toggle link 14 and the upper end of the handle lever 8 and the toggle link that is pivotally connected to the latch 11 and the contact holder 4 by the support pins 15 and 16, respectively. It becomes an assembly with (a tension spring) 17. Reference numeral 18 denotes a trip cross bar linked to the latch receiver 10, and 19 denotes a contact pressure spring that presses the contact 3 a of the movable contact 3 against the contact 2 a of the fixed contact 2 in the closed position.

  Further, as a stopper means corresponding to the isolation function described above, a convex cam 12a is formed on the side edge of the upper link 12, and the ON side side (the left side in the figure) of the handle lever 8 is opposed to the convex cam 12a. ) Is provided with a stopper piece 8a whose tip is bent into a "<" shape. Further, as the opening member, the opening / closing mechanism 6 has a Y-shaped separation plate 20 having one end pivotally supported by the toggle pin 14 and the tip opposed to the trip cross bar 18 and the stopper piece 8a of the handle lever 8. The separation plate 20 is spring-biased counterclockwise by a torsion coil spring provided on the shaft of the toggle pin.

  The opening / closing and tripping operation of the circuit breaker configured as described above is described in detail in Patent Document 1, and when the operating handle 7 is brought to the ON position (see FIG. 8), the opening / closing spring 17 receives the spring force. The upper link 12 of the toggle link (the support shaft 15 on the upper end side becomes a fixing point) and the lower link 13 extend almost linearly to push the contact holder 4 counterclockwise, and the contact 3a of the movable contact 3 is fixed. The main circuit contact is in contact with the contact 2a of the contact 2 and closed. When the operating handle 7 is tilted to the OFF position (see FIG. 9) from this state, the spring force acting line of the open / close spring 17 is reversed beyond the dead point (support shaft 15 of the upper link 12), thereby the toggle link mechanism. The upper link 12 and the lower link 13 buckle in an inverted “<” shape, the contact holder 4 rotates clockwise, and the movable contact 3 moves away from the fixed contact 2 to open the main circuit contact. To the extreme.

  FIG. 10 shows a state in which the main circuit contact is opened by the trip operation. An overcurrent tripping device (not shown) is detected by detecting an overcurrent flowing through the main circuit in the ON state of FIG. When activated, its mechanical output strikes the trip crossbar 18 and the latch receiver 10 releases the latch 11 lock. As a result, the latch 11 is rotated counterclockwise about the support shaft 9 by the spring force of the opening / closing spring 17, and the support shaft pin 15 of the upper link 12 that is driven and coupled to the latch 11 is moved to the position shown in FIG. It is displaced to. As a result, the lower link 13 connected to the upper link 12 via the toggle pin 14 is pulled upward, and the contact holder 4 rotates clockwise to open the movable contact 3. In this trip operation state, the operation handle 7 stops at the illustrated trip display position (between the ON position and the OFF position), and the upper end support shaft 15 of the upper link 12 connected to the latch 11 moves to the illustrated position. . In order to re-insert the circuit breaker from this trip operation state, the operation handle 7 is moved from the TRIP position to the OFF position (see FIG. 9), the latch 11 is reset, and then it is again moved to the ON position (see FIG. 8). .

  On the other hand, when the handle 7 is moved from the ON position toward the OFF position in order to turn off the circuit breaker in a state where the main circuit contact is welded, the handle lever 8 is moved while the handle 7 is moving as shown in FIG. The stopper piece 8 a pushes the separation plate 20. Therefore, the separation plate 20 tilts clockwise with the toggle pin 14 as a fulcrum, and the front end of the plate pushes the latch receiver 10 to release the engagement of the latch 11. As a result, a force that causes the latch 11 to rotate counterclockwise about the support shaft 9 as a fulcrum is caused by the spring force (tensile spring force) of the opening / closing spring 17 that spans between the handle lever 8 and the toggle pin 14. The contact force is applied to the contact holder 4 via the lower link 13 in conjunction with this. Since this opening force F acts in the direction of moving the movable contact 3 away from the fixed contact 2, if the welding of the contact is slight, the welding is peeled off and the movable contact 3 is opened, and the trip operation of FIG. Transition to the state.

If the welding state of the contact is severe and the welding is not peeled off even by the aforementioned handle operation, the stopper piece 8a of the handle lever 8 is engaged with the protrusion 12a of the upper link 12 as shown in FIG. The handle 7 is prevented from further moving from the illustrated position to the OFF position (isolation function).
JP 2000-32003 A (page 4-7, FIGS. 1 to 6)

  By the way, the above-described conventional opening / closing mechanism (Patent Document 1) has the following problems in terms of the opening force for tearing off the welded contact, the number of parts, and the assembly surface.

  That is, in order to separate the welded state by operating the handle in the contact welded state, the illustrated separation plate 20 and the separation plate are used as a separation member for releasing the latch of the opening / closing mechanism during the movement of the handle 7. Since 20 urging springs (torsion coil springs) are required, the number of parts and assembly man-hours of the opening / closing mechanism are increased, and the cost of the product is increased.

  In addition, when the contact is welded, the release force acting on the movable contact is small due to the operation when the latch of the opening / closing mechanism is released through the above-mentioned release member by operating the handle, and the weld between the contacts can be peeled off. Is limited to extremely light welding conditions.

  That is, as shown in FIG. 11, the position of the toggle link is shown in FIG. 8 in the state immediately after the latch 11 is released through the separation plate 20 by the operation of moving the handle 7 in the OFF direction in the contact welding state. The upper end of the upper link 12 is fixedly connected to the latch 11 via the support shaft 15 so that the latch 11 is restrained by the upper link 12 and the lower link 13. It cannot be freely rotated to the release position (see FIG. 10).

  For this reason, the opening force F acting on the contact 3 so that the contact welding is peeled off by the spring force of the open / close spring 17 spanned between the handle lever 8 and the toggle pin 14 is as follows. That is, in the state immediately after the release of the latch shown in FIG. 11, the upper link 12 receives a counterclockwise rotational torque from the support shaft 15 by the spring force of the opening / closing spring 17, and this rotational torque causes the lower link 13 to To the contact piece holder 4, and acts as a separation force F of the movable contact piece 3.

  However, as can be seen from the position of the toggle link in FIG. 11, the distance between the axis line connecting the support shaft 15 connecting the upper end of the upper link 12 to the latch 11 and the toggle pin 14 and the spring force acting line of the opening / closing spring 17. The angle is a small acute angle. Therefore, when the spring force of the opening / closing spring 17 is divided into a vector component in the direction along the axis of the upper link 12 and a vector component (rotational torque) for rotating the upper link 12 in the counterclockwise direction, the spring of the opening / closing spring 17 is divided. Most of the force is a vector component along the axis of the upper link 12, and the rotational torque acting on the upper link 12 is very small. That is, the efficiency of converting the spring force of the opening / closing spring 17 into the rotational torque of the upper link 12 is low. For this reason, the separation force F which pulls up the movable contact 3 against the welding of the contact is also small, and the welding of the contact is peeled off by the release operation of the latch 11 unless the welding state is extremely light. Will be difficult.

  In addition, the contact opening operation described above functions only when the latch is manually released by manual operation of the handle, and the latch is released by the trip operation by the overcurrent tripping device in the energized state where contact welding has occurred. In this case, it will function only by the forced opening operation with the handle after the trip operation, but even in this case, the efficiency of converting the spring force of the open / close spring to the rotational torque of the upper link is low as described above. A sufficient opening force cannot be obtained.

  The present invention has been made in view of the above points, and its object is to solve the above-mentioned problems, and the structure of the pivot joint between the upper link of the toggle link and the latch without adding new parts. It is an object to provide a circuit breaker with an isolation function that improves the breaking operation reliability by enhancing the opening force acting on the movable contact during the trip operation in the contact welding state. .

In order to achieve the above object, according to the present invention, a movable contact held by a stationary contact of a main circuit and a rotary contact holder, an opening / closing mechanism linked to the contact holder, an operation handle, and an overcurrent A circuit breaker equipped with a tripping device, wherein the opening / closing mechanism has a handle lever that is pivotally supported at the tip by a frame and coupled to an operation handle, and one end that is pivotally supported by the frame and always latches the tip claw. It consists of a latch that is locked to the lock and held in the locked position, and an upper link and a lower link that are joined via a toggle pin. The other end of the upper link and the lower link is used as a latch and a contact holder, respectively. It consists of an assembly of a toggle link that is pivotally connected and spanned, and an open / close spring stretched between the toggle pin and the upper end of the handle lever. The main circuit contacts are opened by turning the handle on and off. And, also at the time of flow of overcurrent in that so as to tripping the switching mechanism to release the latch,
In the trip operation with contact welding between the fixed / movable contacts, the toggle link between the upper link of the toggle link and the latch can be rotated to the release position without receiving the interference interference of the upper link. It is assumed to be slidably pivotally connected . Specifically , a long- hole bearing portion is formed at the upper end of the upper link, and the connecting shaft portion provided in the latch is fitted into the long hole of the bearing portion to latch. The upper link is slidably connected between the upper link and the upper link .
As an isolation mechanism that prevents the handle from moving to the OFF position by a manual handle operation when the movable contact does not open due to a trip operation with the contacts welded, it projects to the side edge of the upper link. to form a Jo cam, provided arm-shaped stopper piece to oN side handle lever opposite the convex cam (claim 2).

  With the above configuration, the return spring force of the open / close spring efficiently acts as the opening force of the movable contactor during the trip operation in the contact welded state.

That is, in the state where the latch is released by the trip operation, the lower link of the toggle link connected to the movable contact via the contact holder is restricted by the welding of the contact and cannot move freely. Can swing freely around. As a result, rotational torque acts on the latch via the upper link due to the spring force of the opening / closing spring applied to the toggle pin (the opening / closing spring is stretched between the toggle pin and the handle lever). Pivots towards the release position. In this case, the upper link is connected to the lower link via the toggle pin, so it does not follow the movement of the latch, but the connecting shaft provided on the latch can freely open the long hole of the bearing part formed at the upper end of the upper link. Since it can slide, the latch and the upper link do not restrain each other. As a result, the return spring force of the open / close spring acts as an opening force that directly pulls up the lower link connected to the toggle pin and peels off the weld between the contacts. That is, the return spring force of the opening / closing spring is effectively converted as the opening force of the movable contact without being converted into the rotational torque of the upper link as in the conventional structure.

  Therefore, even if the welding state between the fixed / movable contacts is somewhat severe, the welding can be peeled off to open the movable contact, and the reliability of the breaking operation is improved.

  In addition to the above configuration, a convex cam is formed on the side edge of the upper link, and an arm-shaped stopper piece is provided on the ON side side of the handle lever so as to face the convex cam. If the contact is not peeled off even by the opening force caused by the trip operation described above, the stopper piece provided on the handle lever is moved to the OFF position while the operation handle is moved to the OFF position. The isolation function can be secured by colliding with the convex cam and preventing further movement of the handle.

  Hereinafter, embodiments of the present invention will be described based on examples shown in FIGS. In addition, in the figure of an Example, the same code | symbol is attached | subjected to the member corresponding to FIGS. 8-11, and the description is abbreviate | omitted.

  First, FIG. 1A shows the overall structure of the circuit breaker, and FIGS. 1B and 2 show the pivot connection structure between the latch of the switching mechanism and the upper link of the toggle link. That is, the open / close mechanism in the circuit breaker of the illustrated embodiment is basically the same as the structure of Patent Document 1 shown in FIG. 8, but the ON side side of the handle lever 8 is provided as a mechanism for providing an isolation function. A stopper piece 8a bent into a "<" shape is formed, and a convex cam 12a (see FIG. 1B) is formed on the side edge of the upper link 12 so as to face the stopper piece 8a.

  Further, in the illustrated embodiment of the pivot connection structure between the latch 11 and the upper link 12, as shown in FIG. 2, a connection shaft 11a is formed on the latch 11, and the upper link 12 is opposed to the connection shaft 11a. The upper end portion is provided with a linear guide portion, and is formed with an open bearing portion 12b that is notched in a U shape along the axial direction of the link. The connecting shaft 11a of the latch is fitted to be pivotally connected between the latch 11 and the upper link 12 so as to be slidable. Note that the U groove of the bearing portion 12b is set to a groove depth so that the connecting shaft 11a does not come out of the U groove even when the latch 11 is rotated to the release position as described later.

  The on, off, and trip operations with the above-described configuration are the same as those of the conventional circuit breaker. When the operating handle 7 is turned to the ON position, the toggle link upper link 12 and lower link 13 are turned on as shown in FIG. Extends substantially linearly and rotates the contact holder 4 counterclockwise, the contact 3a of the movable contact 3 abuts against the fixed contact 2 to close the main circuit contact. Further, when the operation handle 7 is tilted to the OFF position (see FIG. 4) from this closed state, the action line of the opening / closing spring 17 is reversed beyond the dead point, thereby the upper link 12 and the lower link 13 of the toggle link mechanism. However, the contact holder 4 rotates in the clockwise direction, and the movable contact 3 moves upward from the fixed contact 2 to open the main circuit contact.

  When an overcurrent flowing through the main circuit is detected in the input state of FIG. 3 and an overcurrent tripping device (not shown) is activated, the mechanical output hits the trip crossbar 18 and the latch receiver 10 Release the latch 11. As a result, the latch 11 is rotated counterclockwise around the support shaft 9 by receiving the return spring force of the open / close spring 17 spanned between the handle lever 8 and the toggle pin 14, and the latch 11 is moved along with this movement. The connecting shaft 11a provided on the left side of the line of action of the open / close spring 17 moves. As a result, the upper link 12 and the lower link 13 of the toggle link are buckled in a reverse “<” shape in response to the return spring force of the opening / closing spring 7, and the contact holder 4 rotates clockwise in conjunction with this. To open the movable contact 3.

  Next, FIG. 6 and FIG. 7 will be described with reference to FIG. 6 and FIG. As shown in FIG. 6, when the trip operation is performed with the contact of the fixed contact 2 and the contact of the movable contact 3 being welded, the latch 11 is released. By the way, in this released state of the latch, the lower link 13 of the toggle link connected to the movable contact 3 via the contact holder 4 is restrained by the welding of the contact and cannot move freely, but the upper link 12 is the toggle pin 14. Can be swung around. Thus, counterclockwise rotational torque acts on the latch 11 via the upper link 12 by the return spring force of the opening / closing spring 17 applied to the toggle pin 14, and the latch 11 receives the rotational torque and uses the support shaft 9 as a fulcrum. It turns toward the release position (position in FIG. 4).

  In this case, since the connecting shaft 11a provided in the latch 11 is pivotally connected so as to be slidable along the guide portion in the U-shaped groove of the open bearing portion 12b formed at the upper end of the upper link 12, the latch 11 The pivot 9 rotates without being restricted by the upper link 12 with the support shaft 9 as a fulcrum, and the upper link 12 swings around the toggle pin 14 counterclockwise as shown in FIG. Move. As a result, due to the difference between the turning locus of the connecting shaft 11a and the turning locus of the bearing portion 12b, a play gap g is generated between the connecting shaft 11a and the bearing portion 12b as shown.

  Therefore, the return spring force f of the open / close spring 17 is not subject to the restriction of the upper link 12 and the latch 11, and the lower link 13 connected to the toggle pin 14 is directly lifted to peel off the weld between the fixed / movable contacts. It acts as a separation force F. That is, the return spring force of the open / close spring 17 is effectively converted as the opening force of the movable contact 3 without being converted into the rotational torque of the upper link 12 as in the conventional structure (see FIG. 11). It becomes like this.

  Thereby, even if the welding state between the contacts is somewhat severe, the welding can be peeled off by the return spring force of the opening and closing spring 17 to open the movable contact 3, and the reliability of the breaking operation is improved.

  Further, when the contact state between the contacts is severe and the movable contact 3 cannot be opened with the separation force F acting on the trip operation, even if the operation handle 7 is moved from this position to the OFF position, the movement On the way, the stopper piece 8a provided on the handle lever 8 abuts and engages with the convex cam 12a formed on the side edge of the upper link 12 to prevent the operation handle 7 from moving further. Thereby, the isolation function of a circuit breaker is securable.

  In the illustrated embodiment, a U-shaped open bearing portion 12b is formed at the upper end of the upper link 12 and is pivotally connected to the connecting shaft 11a of the latch 11. Instead of the bearing portion 12b, an elongated hole-shaped bearing portion in the link shaft direction is formed at the upper end of the upper link 12, and the coupling shaft 11a of the latch 11 is fitted into the elongated hole so as to be slidably supported. May be. In this structure, the connecting shaft 11a is separated from the latch 11 in consideration of the assembling property of the opening / closing mechanism, and is fixed to the latch 11 while being fitted in the elongated hole of the upper link 12.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the circuit breaker by the Example of this invention, (a) is an internal structure figure of the whole circuit breaker, (b) is the assembly structure of the latch of the switching mechanism in FIG. Perspective view Exploded perspective view of FIG. The side view showing the ON operation state of the opening-and-closing mechanism in FIG. Side view showing the off-operation state of the opening / closing mechanism Side view showing the trip operation state of the open / close mechanism Side view showing trip operation state of switching mechanism in contact welding state Explanatory drawing of the action of the opening and closing spring during the trip operation of FIG. The figure showing an ON state in the lineblock diagram of the circuit breaker currently indicated by patent documents 1 The side view showing the OFF operation state of the opening-and-closing mechanism in FIG. The side view showing the trip operation state of the opening-and-closing mechanism in FIG. The figure showing the trip operation state in the contact welding state in the circuit breaker of FIG.

2 fixed contact 3 movable contact 4 contact holder 6 opening / closing mechanism 6a frame 7 operation handle 8 handle lever 8a stopper piece 9 latch support shaft 11 latch 12 upper link 12a of toggle link convex cam 12b open bearing 13 lower Link 14 Toggle pin 17 Opening and closing spring

Claims (2)

A circuit breaker equipped with a stationary contact of a main circuit and a movable contact held by a rotary contact holder, an opening / closing mechanism linked to the contact holder, an operation handle, and an overcurrent trip device, The opening / closing mechanism is pivotally supported by the handle with the tip pivoted to the frame, and one end pivotally supported by the frame. A toggle link which is composed of an upper link and a lower link coupled via a toggle pin, the other end of the upper link and the lower link being pivotally connected to a latch and a contact holder, respectively, and the toggle pin And an open / close spring stretched between the handle lever and the upper end of the handle lever. The main circuit contacts are opened and closed by turning the handle ON and OFF, and the latch is released when overcurrent flows. In to that so as to tripping the switching mechanism,
A long-hole bearing at the upper end of the upper link so that the latch can be rotated to the release position without receiving the restraining interference of the upper link during a trip operation with contact welding between the fixed and movable contacts The circuit breaker is characterized in that the connecting shaft portion provided in the latch is fitted into the long hole of the bearing portion and is pivotally connected between the upper link of the toggle link and the latch. In the circuit breaker according to claim 1, as an isolation mechanism for preventing the operation handle from moving to the OFF position with the main circuit contact welded, a convex cam is formed on the side edge of the upper link, A circuit breaker characterized in that an arm-shaped stopper piece is provided on the ON side side of the handle lever so as to face the convex cam .

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