JP4026567B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker such as a circuit breaker for wiring and an earth leakage breaker, and more particularly to a circuit breaker having an opening / closing mechanism having a function of forcibly opening a welded contact.

  It is known that when a movable contact and a fixed contact of a circuit breaker in a closed state are welded, the welding is forcibly released by raising the handle of the circuit breaker to the open position side. . In the conventional circuit breaker, as the separating means, the handle arm pulls up the cross bar that pivotally supports the movable contact in the same direction as the direction in which the movable contact having the movable contact opens. (For example, refer to Patent Document 1).

JP-A-7-302534 (paragraph number 0014, FIGS. 1 to 3)

  In general, in order to improve the breaking performance of a circuit breaker, the distance between the movable contact and the fixed contact is increased, and the arc generated between the two contacts is stretched to extinguish the arc quickly. In order to secure this separation distance in a limited space, an attempt is made to drive near the center of rotation of the crossbar. As a result, the center of rotation of the crossbar and the handle arm that moves integrally with the handlebar are driven. The center of rotation must be close. Furthermore, the distance between the handle operating portion and the rotation center of the handle arm, and the distance between the contact point of both contacts and the rotation center of the handle arm are also substantially equal due to restrictions on the configuration as a circuit breaker. .

  Then, when the movable contact and the fixed contact are welded, even if the handle arm tries to pull up the cross bar in the same direction as the opening of the movable contact, the force that forcibly tilts the handle to the open position side is It is merely generated as the peeling force of both contacts as it is, and there is a drawback that it cannot cope with stronger welding.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a circuit breaker having an open / close mechanism that dramatically improves the peeling force between a welded movable contact and a fixed contact. Is.

  In the circuit breaker according to the present invention, when the handle is moved to the open circuit position, the crossbar or the cross in the direction substantially parallel to the contact surface of the two contacts only when the handle arm is welded to the movable contact is fixed. It is comprised so that it may contact | abut to a bar pin.

  As described above, the present invention has a handle arm pivotally supported by a fixed frame and operated by a handle, an upper link and a lower link, and an open / close spring is stretched between the connecting portion and the handle arm. A pivoted toggle link mechanism, a crossbar connected to the lower link by a crossbar pin and rotated by the operation of the toggle link mechanism, a movable contact at one end, and the other end pivotable And a circuit breaker including a movable contact that is interlocked with the rotation of the crossbar and a fixed contact that has a fixed contact that is in contact with and away from the movable contact. When the movable contact and the fixed contact are welded, When the handle is moved to the open position, the handle arm moves the crossbar or crossbar pin in a direction substantially parallel to the contact surface between the movable contact and the fixed contact. And since it is configured to abut, it is possible to obtain a circuit breaker having a closing mechanism with dramatically improved peel strength of the movable contact welded with the fixed contact.

  1 is a cross-sectional view showing a closed state of the circuit breaker, FIG. 2 is a side cross-sectional view of the main part of the opening / closing mechanism portion of FIG. 1, FIG. 3 is a cross-sectional view showing the open state of the circuit breaker, and FIG. FIG. 5 is a cross-sectional view showing a trip state of the circuit breaker, FIG. 6 is a cross-sectional view showing a contact welding state of the circuit breaker, and FIG. 7 is a main view of the open / close mechanism portion of FIG. FIG.

  In FIG. 1, both ends of a cross bar 2 formed of a synthetic resin material are rotatably supported by a base 1 formed of a synthetic resin material or a fixed frame 3 attached to the base 1. A movable contact 4 having a movable contact 5 at one end is pivotally supported inside the cross bar 2 so as to rotate in conjunction with the rotation of the cross bar 2. A fixed contact 6 having a fixed contact 7 that contacts and separates from the movable contact 5 is mounted on the base 1. In FIG. 2, the lower end of the lower link 8 is connected to the crossbar 2 by a crossbar pin 10, and the upper end of the lower link 8 is connected to the lower end of the upper link 9 by a link connecting pin 11. . The upper end of the upper link 9 is connected to a tripping lever 12 whose one end is engaged with the tripping device 13. An opening / closing spring 16 is stretched between the link connecting pin 11 and the handle arm 14 interlocking with the handle 15 formed of a synthetic resin material. The toggle link mechanism 17 is configured by the lower link 8, the upper link 9, and the link connecting pin 11. When the handle 15 is operated in the right direction on the paper surface, the action line of the opening / closing spring 16 causes the deadline of the toggle link mechanism 17 to be dead. By exceeding the point, the toggle link mechanism 17 can be expanded rapidly and the circuit breaker can be kept closed. The contact pressure of the movable contact 5 at this time is such that a contact pressure spring 18 having one end applied to the crossbar 2 and the other end applied to the other end of the movable contact 4 makes the movable contact 4 a fixed contact. It is generated by energizing in 7 directions.

  As can be seen from FIG. 2, the handle arm 14 and the crossbar pin 10 are separated when the circuit breaker is closed. From this state, when the handle 15 is tilted to the open position side, that is, to the left in the drawing, the action line of the opening / closing spring 16 again exceeds the dead point of the toggle link mechanism 17 and the toggle link mechanism 17 bends. That is, the lower link 8 pulls up the crossbar pin 10 and the crossbar 2 rotates counterclockwise on the paper surface, so that the movable contact 4 is lifted. Therefore, as shown in FIG. And the fixed contact 7 is released. In this case as well, since the crossbar pin 10 moves to the position shown in FIG. 4 before the handle arm 14 moves from the position shown in FIG. 2 to the position shown in FIG. The pins 10 do not interfere with each other. Further, as shown in FIG. 5, even when the circuit breaker tripping device 13 operates, that is, when the circuit breaker is shifted to the trip state, the release lever 12 is disengaged from the tripping device 13 on the paper surface. The movement of the crossbar pin 10 due to the bending of the toggle link mechanism 17 interlocked with the clockwise rotation is performed without interference with the handle arm 14.

  Now, it is assumed that, for example, a pulsed current flows through the circuit breaker in the closed state, and the movable contact 5 and the fixed contact 7 are welded. In this state, when the handle 15 is moved to the left in FIG. 1 in order to open the circuit breaker due to the necessity of maintenance and inspection of the circuit, the lower link 8 pulls up the crossbar pin 10. 2 is brought into contact with the welded movable contact 4 to stop its rotation, and the crossbar pin 10 is stationary. At the same time, the handle arm 14 is also rotated counterclockwise on the paper surface so as to be interlocked with the leftward movement of the handle 15 on the paper surface. However, the crossbar pin 10 is stationary on the rotation trajectory of the handle arm 14. Therefore, as shown in FIG. 7, the first protrusion 14a of the handle arm 14 and the crossbar pin 10 come into contact with each other. At this time, as can be seen from the drawing, the first protrusion 14 a of the handle arm 14 is substantially parallel to the contact surface (in this case, the welding surface) of the movable contact 5 and the fixed contact 7 with respect to the crossbar pin 10. Abutting in the direction. In this figure, the tripping device 13 does not work with the current until the movable contact 5 and the fixed contact 7 are welded. That is, the positional relationship between the tripping lever 12 and the tripping device 13 is the same as in FIG. Although the case where the tripping device 13 is operated by the current up to the welding and the release lever 12 is disengaged from the tripping device 13 is shown, the cross bar 2, the movable contact 4, the cross The positional relationship of the bar pins 10 is almost the same as that in FIG.

Similarly, as can be seen from the figure, when the handle arm 14 is pivoted to the fixed frame 3 (hereinafter referred to as pivot point 3a), and the handle 15 is tilted leftward on the paper surface from this state, the handle 15 The distance L2 of the point at which the hand is clamped by hand (hereinafter referred to as the clamping point 15a) is the contact point between the first protrusion 14a of the handle arm 14 and the crossbar pin 10 (hereinafter referred to as the contact point 10a) and the pivot point. It is about 3 times the distance L1 of 3a. Therefore, when the force for raising and lowering the handle 15 in the left direction on the paper surface is F2, the force F1 for pushing the cross bar pin 10 by the first protrusion 14a of the handle arm 14 is expressed by the following equation.
From F1 × L1 = F2 × L2 and L2 = L1 × 3,
F1 × L1 = F2 × L1 × 3, so F1 = F2 × 3
In other words, due to restrictions on the circuit breaker configuration, the distance between the abutment point 10a and the pivot point 3a is shorter than the distance between the pivot point 3a and the clamping point 15a (in this case, about 1/3). By tilting 15 in the left direction on the paper surface, a large pushing force (in this case, about three times the force for tilting the handle 15 in the left direction on the paper surface) can be applied to the crossbar pin 10. .

  If the contact point 10a and the center of rotation of the crossbar 2 are arranged on a straight line with respect to the welded portion of the movable contact 5 and the fixed contact 7, the large pushing force is small and the shearing force is small. It works as effectively. Furthermore, if the welding surface of the movable contact 5 and the fixed contact 7, the contact point 10a, and the rotation center of the cross bar 2 are arranged in a straight line, that is, the distance L3 between the contact point 10a and the rotation center of the cross bar 2 is When it is zero, it is played as a shearing force that shifts the welding surfaces of the movable contact 5 and the fixed contact 7 almost as they are. Therefore, in consideration of the fact that the distance L2 between the pivot point 3a and the clamping point 15a is substantially unchanged in the form of the circuit breaker, the shorter the distance L1 between the abutment point 10a and the pivot point 3a, the more effective the shear. Power can be obtained, that is, the ability of welding and breaking can be increased.

  The relationship between the large pushing force (F1) and the shearing force that shifts the welding surface does not depend on the distance L4 between the rotation center of the crossbar 2 and the contact surface between the movable contact 5 and the fixed contact 7. This can be effectively applied to a circuit breaker having a longer L4 in order to extend the contact opening distance. On the other hand, as can be seen from FIG. 7, the contact point 10a and the rotation center of the crossbar 2 are not necessarily arranged at parallel positions with respect to the welding surfaces of the movable contact 5 and the fixed contact 7, so that the shearing force is reduced. In the first place, in this embodiment, the contact point 10a is put on the crossbar pin 10, so that a circuit breaker having a compact configuration can be obtained without adding special parts. Can do.

  As described above, according to this configuration, when the movable contact 5 and the fixed contact 7 are welded, the first protrusion 14a of the handle arm 14 and the crossbar pin 10 are brought into contact with each other by raising the handle 15 in the left direction on the paper surface. Even after the contact, if the force that further raises and lowers the handle 15 in the left direction on the paper surface is continued, the welding of the movable contact 5 and the fixed contact 7 can be easily peeled off. Since the dead point of the toggle link mechanism 17 is exceeded, the toggle link mechanism 17 is bent, so that the circuit breaker can be opened. This increases the adhesion peel strength without significantly changing the form of the circuit breaker, specifically, without significantly changing the positional relationship between the rotation center of the crossbar 2 and the rotation center of the handle arm 14. This means that an isolated circuit breaker can be obtained.

  Further, since the first protrusion 14a of the handle arm 14 is brought into contact with the crossbar pin 10, the handle arm 14 in the normal closed and open state of the circuit breaker described above or the trip state of the circuit breaker Since the crossbar pin 10 does not interfere more, it is not necessary to enlarge the switching mechanism of the circuit breaker. Furthermore, by making contact with the crossbar pin 10, it is possible to prevent deformation of the crossbar 2 due to a large force generated at the time of contact.

  In addition, as shown in FIG. 3, when the circuit breaker is in the open state, the crossbar 2 has a backlash a corresponding to the movement allowance of the crossbar 2 with respect to the fixed frame 3. Then, as shown in FIG. 1, when the circuit breaker is closed, the second protrusion 14b of the handle arm 14 urges the crossbar 2 in the direction opposite to the shearing force using the play a. deep. As a result, when the handle 15 is operated in the opening direction when the movable contact 5 and the fixed contact 7 are welded, the crossbar 2, in other words, the crossbar pin 10 can be moved by a necessary stroke in the direction in which the shearing force acts. Furthermore, the welding separation ability can be enhanced.

  By the way, when the welding of the movable contact 5 and the fixed contact 7 is strong and the welding cannot be peeled off even with the means described so far, the handle arm 14 or the first protrusion 14a is provided with a crossbar. The pin 10 becomes a stopper, and further movement in the right direction on the paper surface of FIG. 6 is restrained. Accordingly, the operation of the handle 15 in the opening direction is impossible, that is, the handle 15 stops at the position shown in the figure, and therefore the off-lock function is not attached to the handle 15 when the movable contact 5 and the fixed contact 7 are welded. It is also possible to provide a circuit breaker having a so-called isolation function.

  In the above description, the circuit breaker has been described, but it is natural that the circuit breaker can also be used for this type of switch, and the transmission path is changed as long as the contact breaking force is parallel to the contact surface. However, it does not depart from the scope of the invention.

It is sectional drawing which shows the closed circuit state of the circuit breaker which shows embodiment of this invention. It is principal part side sectional drawing of the opening-closing mechanism part which shows the closed circuit state of the circuit breaker which shows embodiment of this invention. It is sectional drawing which shows the open circuit state of the circuit breaker which shows embodiment of this invention. It is principal part side sectional drawing of the switching mechanism part which shows the open circuit state of the circuit breaker which shows embodiment of this invention. It is sectional drawing which shows the trip state of the circuit breaker which shows embodiment of this invention. It is sectional drawing which shows the contact welding state of the circuit breaker which shows embodiment of this invention. It is principal part side sectional drawing of the switching mechanism part which shows the contact welding state of the circuit breaker which shows embodiment of this invention.

Explanation of symbols

2 Crossbar, 3 frames, 4 movable contacts, 5 movable contacts,
6 fixed contact, 7 fixed contact, 8 lower link, 9 upper link,
10 crossbar pin, 14 handle arm, 14a first protrusion,
14b Second protrusion, 15 handle, 16 Opening / closing spring,
17 Toggle link mechanism, a backlash

Claims (7)

A handle arm pivotally supported by a fixed frame and operated by a handle; a toggle link mechanism having an upper link and a lower link, and an open / close spring stretched between the connecting portion and the handle arm; and A crossbar connected to the lower link by a crossbar pin and rotated by the operation of the toggle link mechanism, and a movable contact at one end and pivotally supported at the other end so that the crossbar can be rotated. In a circuit breaker comprising a movable contact that is interlocked and a fixed contact that has a fixed contact that contacts and separates from the movable contact,
When the handle is moved to the open position during welding of the movable contact and the fixed contact, the handle arm moves the crossbar or the crossbar in a direction substantially parallel to the contact surface between the movable contact and the fixed contact. A circuit breaker configured to abut against a pin. The circuit breaker according to claim 1, wherein the handle arm is configured to abut against the crossbar pin. The distance between the contact point of the handle arm with the crossbar pin and the pivot point of the handle arm is configured to be smaller than the distance between the operation portion of the handle arm and the pivot point of the handle arm. Circuit breaker described in. The circuit breaker according to claim 3, wherein a contact point of the handle arm with the crossbar pin is located in the vicinity of a pivot point of the handle arm. The center of rotation of the crossbar, the contact point of the handle arm with the crossbar or the crossbar pin, and the contact portion between the movable contact and the fixed contact are arranged substantially in a straight line. Item 3. The circuit breaker according to item 1 or 2. The said handle arm is comprised so that the said crossbar may be urged | biased to the position which maintains the movement allowance of the said crossbar when the said handle | steering-wheel is a closed position. Circuit breaker. The circuit breaker according to claim 2, wherein a protrusion provided on the handle arm is configured to contact the crossbar pin.

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