Circuit breaker

Abstract

To prevent buckling of a coil spring for applying force to a turning cutoff latch.SOLUTION: A circuit breaker (10) includes a power transmission mechanism (12) that drives a movable contact (17) and a fixed contact (18) in a direction in which the movable contact and the fixed contact are brought into contact with and separated from each other, a breaking spring (13) that can accumulate a driving force in a direction in which the movable contact is separated from the fixed contact via the power transmission mechanism, and a breaking control mechanism (15) that controls a breaking operation of the power transmission mechanism. The breaking control mechanism includes a breaking latch (23) that restricts a breaking operation of the power transmission mechanism at a locking position where the breaking latch is locked to the lever portion (22), and is rotated by a predetermined operation to be displaced to an unlocking position where the breaking latch is unlocked from the lever portion to start the breaking operation of the power transmission mechanism, a coil spring (32) that exerts an elastic force for rotating the breaking latch from the unlocking position to the locking position, and a buckling prevention mechanism (33) that suppresses deformation of the coil spring in a direction in which the coil spring is bent with respect to an extending direction of a central axis when the breaking latch is rotated from the locking position to the unlocking position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a circuit breaker used to make and break current. [Background technology]

[0002] Patent Document 1 discloses a circuit breaker equipped with a circuit breaker control unit that mechanically controls the circuit breaking operation. The circuit breaker control unit includes a main lever attached to a main shaft, a circuit breaker latch that is rotatably supported and engages with the main lever to prevent rotation of the main lever, and a return spring attached to the middle of the circuit breaker latch. When transitioning from the circuit breaking state to the circuit closing state, the main lever and the circuit breaker latch are disengaged, and the force of the return spring causes the circuit breaker latch to rotate and engage with the main lever. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-209554 Summary of the Invention [Problem to be solved by the invention]

[0004] The return spring in Patent Document 1 is a compression coil spring, one end of which is attached to the middle of the breaking latch and the other end of which is attached to the housing. In the closed state, one end of the return spring is parallel to the other end, but in the broken state, the rotation of the breaking latch causes one end of the return spring to tilt relative to the other end of the return spring, which creates a problem of making the return spring more susceptible to buckling.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a circuit breaker that can prevent buckling of a coil spring that applies force to a rotating breaking latch. [Means for solving the problem]

[0006] One embodiment of the circuit breaker of the present invention is a circuit breaker comprising: a power transmission mechanism that drives a movable contact and a fixed contact that constitute an opening / closing contact in directions to move them together; a breaker spring that can store a driving force in a direction to pull the movable contact away from the fixed contact via the power transmission mechanism; an opening / closing shaft connected to the power transmission mechanism; and a breaker control mechanism that controls the breaker operation of the power transmission mechanism by the breaker spring, wherein the breaker control mechanism comprises: a lever portion provided on the opening / closing shaft; a breaker latch that regulates the breaker operation of the power transmission mechanism at an engagement position where it engages with the lever portion, and that rotates by a predetermined operation to a disengagement position where it releases the engagement with the lever portion and starts the breaker operation of the power transmission mechanism; a coil spring that exerts an elastic force to rotate the breaker latch from the disengagement position to the engagement position; and a buckling prevention mechanism that suppresses deformation of the coil spring in a bending direction relative to the extension direction of the central axis when the breaker latch rotates from the engagement position to the disengagement position. [Effects of the Invention]

[0007] According to the present invention, since the buckling prevention mechanism is provided, it is possible to prevent the coil spring from buckling due to the rotation of the breaking latch. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are schematic front cross-sectional views showing the internal structure of a circuit breaker according to a first embodiment. [Figure 2] 2A is a front view of the cutoff control mechanism of FIG. 1A, and FIG. 2B is a side view of FIG. 2A. [Figure 3] 3A is a front view of the cutoff control mechanism of FIG. 1B, and FIG. 3B is a side view of FIG. 3A. [Figure 4] 4A and 4B are schematic cross-sectional front views of a cutoff control mechanism according to the second embodiment. [Figure 5] 5A and 5B are schematic cross-sectional front views of a cutoff control mechanism according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a circuit breaker according to an embodiment will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment, and can be appropriately modified and implemented without departing from the spirit of the present invention. In the following drawings, some components may be omitted for the sake of convenience. Furthermore, in the following description, unless otherwise specified, "up," "down," "left," "right," "front," and "rear" refer to the directions indicated by arrows in each drawing. However, the orientation of each component in the following embodiment is merely an example, and can be changed to any orientation.

[0010] [First embodiment] 1A and 1B are schematic front cross-sectional views showing the internal structure of a circuit breaker according to the first embodiment. A circuit breaker 10 includes an open / close contact 11, a power transmission mechanism 12, and a breaker spring 13 (all of which are shown simply), an open / close shaft 14 connected to the power transmission mechanism 12 and extending in the front-rear direction (the direction perpendicular to the plane of the paper in FIG. 1), and a breaker control mechanism 15.

[0011] The make-and-break contact 11 is configured with a movable contact 17 and a fixed contact 18 that can be made or separated, and is in a closed state (closed circuit state) when the contacts 17, 18 are in contact, and in a broken state (open circuit state) when the contacts are separated. Note that Fig. 1A and Figs. 2A and 2B, which will be described later, show the make-and-break state of the make-and-break contact 11, and Fig. 1B and Figs. 3A and 3B, which will be described later, show the broken state of the make-and-break contact 11.

[0012] The power transmission mechanism 12 is connected to the opening / closing shaft 14 and is configured by an operating mechanism that converts the rotational movement of the opening / closing shaft 14 to drive the movable contact 17 in the direction of contacting and separating with respect to the fixed contact 18 .

[0013] The breaking spring 13 is connected to the tip of a breaking spring lever 20 that is connected to the opening / closing shaft 14 and extends in a direction away from the opening / closing shaft 14, and applies a biasing force to the breaking spring lever 20. In the closed state of FIG. 1A , the breaking spring 13 stores elastic force in a direction that moves the tip of the breaking spring lever 20 downward, and is released by releasing a breaking latch 23, which will be described later. When the breaking spring 13 is released, the tip of the breaking spring lever 20 moves downward and rotates the opening / closing shaft 14, causing the power transmission mechanism 12 to perform a breaking operation, and the opening / closing contact 11 changes from the closed state to the broken state. Therefore, the breaking spring 13 is arranged to be able to store a driving force in a direction that moves the movable contact 17 away from the fixed contact 18 via the power transmission mechanism 12.

[0014] The cutoff control mechanism 15 controls the initiation and regulation of the cutoff operation of the power transmission mechanism 12 by the cutoff spring 13. In addition to the cutoff spring lever 20 described above, the cutoff control mechanism 15 includes a lever portion 22 that extends generally upward from the opening / closing shaft 14, and a cutoff latch 23 that can be engaged with the lever portion 22.

[0015] 2A is a front view of the cutoff control mechanism of FIG. 1A, and FIG. 2B is a side view of FIG. 2A. FIG. 3A is a front view of the cutoff control mechanism of FIG. 1B, and FIG. 3B is a side view of FIG. 3A. As shown in FIGS. 2B and 3B, lever portion 22 has two lever bodies 25 that are plate-shaped bodies of the same shape. The two lever bodies 25 are arranged at a predetermined distance in the front-rear direction, and each has its lower end connected to opening / closing shaft 14 as a base. Therefore, lever portion 22 rotates integrally with opening / closing shaft 14, and as shown in FIGS. 1A and 1B, the upper end (tip) side can rotate so as to move back and forth generally left and right.

[0016] Lever portion 22 further includes a locking roller 26 sandwiched between the upper end sides (tip sides) of two lever bodies 25, and a connecting piece 27 connecting the upper left corner portions of the two lever bodies 25. Locking roller 26 is disposed at the upper right corner portion of lever portion 22, and is provided so that the right side protrudes from lever body 25 when viewed from the front-to-rear direction.

[0017] The breaking latch 23 is rotatably supported via a support shaft 29, which is disposed above and to the right of the opening / closing shaft 14 and extends in the front-to-rear direction. The breaking latch 23 extends generally leftward from the support shaft 29 and is supported by the support shaft 29 with its right end side as a base. A roller 30 is provided above the tip of the breaking latch 23. A locking portion 31 is formed in the lower corner of the tip of the breaking latch 23, recessed in an L shape (recessed corner).

[0018] 1A, the locking portion 31 abuts at the right end of the locking roller 26. This abutment causes the locking portion 31 (breaking latch 23) and the locking roller 26 (lever portion 22) to be locked together, and when the locking roller 26 is released from the locking portion 31 as shown in FIG. 1B, the locking portion 31 and the locking roller 26 are released from each other. Here, the position of the breaking latch 23 shown in FIG. 1A is the locked position, and the position shown in FIG. 1B is the unlocked position.

[0019] When the breaking latch 23 is in the locking position where it is locked with the lever portion 22, it restricts the clockwise rotation of the lever portion 22, which receives the driving force of the breaking spring 13, and the opening / closing shaft 14. Therefore, when the breaking latch 23 is in the locking position, it keeps the breaking spring 13 in a charged state by engaging with the lever portion 22, and the breaking control mechanism 15 can be controlled to restrict the breaking operation of the power transmission mechanism 12. Furthermore, when the locking between the breaking latch 23 and the lever portion 22 is released, the charged breaking spring 13 is released, and the breaking control mechanism 15 can be controlled to start the breaking operation of the power transmission mechanism 12.

[0020] The breaking control mechanism 15 further includes a coil spring 32 provided above the breaking latch 23 to exert an elastic force for rotating the breaking latch 23 , and a buckling prevention mechanism 33 provided around the coil spring 32 .

[0021] The coil spring 32 is a compression coil spring in which wire is wound in a spiral shape and the central axis extends in the vertical direction. The coil spring 32 exerts an elastic force, via the buckling prevention mechanism 33, that rotates the breaking latch 23 from the unlocked position to the locked position.

[0022] The buckling prevention mechanism 33 includes a guide hole 35, an adjustment screw (adjustment portion) , a spring holder 37, and a connecting member .

[0023] The guide hole 35 is formed, for example, by drilling a hole in the housing 40, and the coil spring 32 is inserted therein. More specifically, the guide hole 35 is formed as a circular hole with an inner diameter that is approximately the same as or slightly larger than the outer diameter of the coil spring 32. Therefore, inside the guide hole 35, the coil spring 32 is able to freely expand and contract along the extension direction of the central axis (up and down direction), and the coil spring 32 is prevented from deforming in a direction that bends relative to the extension direction of the central axis. The coil spring 32 is arranged so that both ends fit inside the guide hole 35 and are not exposed to the outside of the guide hole 35.

[0024] A female thread 41 is formed on the upper inner circumferential surface of the guide hole 35, and an adjustment screw 36 is threadedly engaged with the female thread 41. Therefore, by rotating the adjustment screw 36, the position of the adjustment screw 36 itself in the vertical direction is displaced. The lower end of the adjustment screw 36 abuts against the upper end of the coil spring 32. As a result, the upper end of the coil spring 32 is positioned by the adjustment screw 36, and by displacing the adjustment screw 36 up or down, the position of the upper end of the coil spring 32 can be adjusted, and the elastic force exerted by the coil spring 32 can be adjusted.

[0025] Spring retainer 37 is connected to the lower end (one end) of coil spring 32 and is disposed inside guide hole 35. Spring retainer 37 is formed in a cylindrical shape with an outer diameter that is approximately the same as or slightly smaller than the inner diameter of guide hole 35. Therefore, spring retainer 37 is able to move up and down inside guide hole 35, and its sliding movement along the inner circumferential surface of guide hole 35 guides its movement in the up and down direction.

[0026] The connecting member 38 extends in the vertical direction (a predetermined direction) and connects the spring presser 37 and the breaking latch 23. The connecting member 38 is formed of two plate-like members that sandwich the breaking latch 23 from both the front and rear sides, and is arranged so as to also sandwich the housing 40, which is the portion where the guide hole 35 is formed, from both the front and rear sides (see FIGS. 2B and 3B).

[0027] The upper end (one end) of the connecting member 38 is connected to the spring holder 37 via an upper pin 43 so as to be rotatable relative to the spring holder 37. The upper pin 43 passes through the portion of the housing 40 where the guide hole 35 is formed in the front-to-rear direction. A vertically long slot 44 is formed in the portion of the housing 40 where the upper pin 43 passes through, allowing the upper pin 43 and the spring holder 37 to move in the vertical direction.

[0028] The lower end (other end) of the connecting member 38 is connected to the breaking latch 23 via a lower pin 45 so as to be relatively rotatable. The installation position of the lower pin 45 on the breaking latch 23 is approximately the middle of the breaking latch 23 in the left-right direction (extension direction).

[0029] Next, the operation of each component when the lever portion 22 and the breaking latch 23 are released from the locked state will be described.

[0030] 1A, the breaking latch 23 is rotated clockwise by a predetermined operation that operates an unlocking latch, plunger, etc. (not shown). When the breaking latch 23 is rotated to the unlocked position shown in FIG. 1B, the locking roller 26 of the lever portion 22 comes out of the locking portion 31 of the breaking latch 23, and the locking therebetween is released. This release of the lock releases the energized breaking spring 13, and the opening / closing shaft 14 and the lever portion 22 rotate clockwise via the breaking spring lever 20, so that the tip of the lever portion 22 is positioned below the breaking latch 23. Note that the release of the energization of the breaking spring 13 separates the movable contact 17 from the fixed contact 18 via the power transmission mechanism 12, resulting in a breaking state.

[0031] When the breaking latch 23 is pivotally displaced from the locked position to the unlocked position, the lower pin 45 connecting the breaking latch 23 and the connecting member 38 is displaced upward and also to the right. Therefore, the breaking latch 23 and the connecting member 38 rotate relative to each other via the lower pin 45, and the connecting member 38 is displaced upward.

[0032] When the connecting member 38 rotates and displaces upward, the connecting member 38 and the spring holder 37 rotate relative to each other via the upper pin 43, and the upper pin 43 displaces upward together with the connecting member 38. At this time, the guide hole 35 guides the spring holder 37 so that it displaces parallel to the vertical direction. In other words, the upward displacement of the spring holder 37 keeps the guide hole 35 in a state where it is restricted from displacing in the horizontal direction (front-back and left-right directions). Therefore, a force acts on the lower end of the coil spring 32 connected to the spring holder 37, pushing it upward without tilting it relative to the vertical direction, which is the direction in which the central axis of the coil spring 32 extends.

[0033] When this force is applied, the coil spring 32 elastically deforms so that its vertical length is shortened, and enters a charged state. During this elastic deformation, the coil spring 32 is inserted into the guide hole 35, so that deformation of the coil spring 32 in a bending direction relative to the extension direction of the central axis is suppressed.

[0034] Due to the stored energy of the coil spring 32, the breaking latch 23 is urged downward via the spring presser 37 and the connecting member 38, and the lower surface of the breaking latch 23 is pressed against the tip of the lever portion 22. In this state, by rotating the opening / closing shaft 14 and the lever portion 22 counterclockwise from the state shown in FIG. 1B via a closing mechanism (not shown), the locking roller 26 locks with the locking portion 31 of the breaking latch 23. At this time, the elastic force of the coil spring 32 is exerted, and the breaking latch 23 is pressed downward via the spring presser 37 and the connecting member 38, and is rotated counterclockwise. Therefore, the coil spring 32 rotates the breaking latch 23 from the unlocked position to the locked position, returning it to the closed state shown in FIG. 1A.

[0035] According to the first embodiment described above, the buckling prevention mechanism 33 can maintain the direction of the force acting on the coil spring 32 due to the rotation of the disconnecting latch 23 in a direction parallel to the extension direction of the central axis of the coil spring 32 (vertical direction).

[0036] More specifically, in the first embodiment, the buckling prevention mechanism 33 guides the spring holder 37 along the inner peripheral surface of the guide hole 35, displacing it in the up-down direction, and the spring holder 37 and the breaking latch 23 are connected by the connecting member 38 and the pins 43, 45 to be relatively rotatable. As a result, even if the connecting position between the connecting member 38 and the breaking latch 23 is displaced in the left-right direction due to rotation of the breaking latch 23, the spring holder 37 can be moved linearly only in the up-down direction without being displaced in the left-right direction. In other words, when the coil spring 32 is energized, the lower end of the coil spring 32 connected to the spring holder 37 is displaced in the extension direction of the central axis of the coil spring 32, which can prevent buckling, in which the coil spring 32 is deformed in a direction bending relative to the extension direction.

[0037] Moreover, since the coil spring 32 is inserted into the guide hole 35, the coil spring 32 is surrounded by the inner peripheral surface of the guide hole 35, which also prevents the coil spring 32 from deforming in a direction bending relative to the direction in which the central axis extends.

[0038] In this way, the buckling prevention mechanism 33 can suppress the occurrence of buckling of the coil spring 32, thereby extending the life of the coil spring 32 and maintaining the elastic force due to the release of the coil spring 32 in a good condition for a long period of time. This also makes it possible to maintain the speed at which the breaking latch 23 moves from the unlocked position to the locked position, preventing the occurrence of poor locking with the lever portion 22 and making the breaking control mechanism 15 highly reliable.

[0039] In addition, in the first embodiment described above, the elastic force exerted by the coil spring 32 can be adjusted by operating the adjustment screw 36, thereby stabilizing and ensuring the engagement between the breaking latch 23 and the lever portion 22.

[0040] Next, other embodiments of the present invention will be described. In the following description, the same reference numerals may be used to designate components that are the same as or equivalent to those in the embodiments described before the embodiment, and the description thereof may be omitted or simplified.

[0041] [Second embodiment] A second embodiment of the present invention will be described with reference to Figures 4A and 4B. Figures 4A and 4B are schematic front cross-sectional views of a cutoff control mechanism according to the second embodiment. Figure 4A shows the closed state, and Figure 4B shows the cutoff state. As shown in Figures 4A and 4B, in a buckling prevention mechanism 50 according to the second embodiment, the configuration of the connection between the cutoff latch 23 and the coil spring 32 is changed compared to the buckling prevention mechanism 33 according to the first embodiment.

[0042] The buckling prevention mechanism 50 in the second embodiment includes a spring retainer 51 that is inserted into the guide hole 35 together with the coil spring 32, and a sliding portion 52 that is formed at the lower end (tip) of the spring retainer 51.

[0043] Spring holder 51 is formed in a cylindrical shape with an outer diameter that is approximately the same as or slightly smaller than the inner diameter of guide hole 35. The upper end of spring holder 51 is connected to the lower end (one end) of coil spring 32 inside guide hole 35. The lower end side of spring holder 51 is provided so as to protrude below guide hole 35. Similar to spring holder 37 of the first embodiment, spring holder 51 slides on the inner circumferential surface of guide hole 35, thereby guiding vertical displacement.

[0044] The sliding portion 52 is formed by the lower end of the spring presser 51 and is integrated with the spring presser 51. The sliding portion 52 is formed in a curved shape with a semicircular cross section that bulges downward. The sliding portion 52 is in point contact or line contact with the upper end surface, which is the upper outer surface of the breaking latch 23, and presses the upper end surface of the breaking latch 23 with the elastic force of the charged coil spring 32. Therefore, the elastic force of the coil spring 32 is transmitted to the breaking latch 23 by the integrated spring presser 51 and sliding portion 52.

[0045] In the second embodiment, when breaking latch 23 is pivotally displaced from the locked position shown in Fig. 4A to the unlocked position shown in Fig. 4B, spring presser 51 is lifted and displaced upward by breaking latch 23. At this time, guide hole 35 guides spring presser 51 so that it displaces parallel to the vertical direction, and a force acts to push spring presser 51 upward without tilting relative to the vertical direction, which is the extension direction of the central axis of coil spring 32.

[0046] Furthermore, due to the rotational displacement of the breaking latch 23, the sliding portion 52 slides so that the contact position of the sliding portion 52 with respect to the upper end surface of the breaking latch 23 is displaced closer to the tip of the breaking latch 23. In other words, the formation of the sliding portion 52 prevents the spring presser 51 from displacing in the left-right direction, and allows the sliding portion 52 to slide on the upper end surface (outer surface) of the turning breaking latch 23. This makes it possible to prevent the lower end of the coil spring 32 connected to the spring presser 51 from displacing in the extension direction (up-down direction) of the central axis of the coil spring 32 when the coil spring 32 is energized, thereby preventing buckling, which is deformation in a direction bending relative to the extension direction.

[0047] As described above, in the buckling prevention mechanism 50 of the second embodiment, as in the first embodiment, it is possible to prevent the coil spring 32 from buckling due to the rotation of the disconnecting latch 23.

[0048] Furthermore, since the sliding portion 52 makes point contact or line contact with the upper end surface of the breaking latch 23, the occurrence of friction during sliding is suppressed, and the turning of the breaking latch 23 and the displacement of the spring presser 51 can be performed smoothly.

[0049] [Third embodiment] A third embodiment of the present invention will be described with reference to Figures 5A and 5B. Figures 5A and 5B are schematic front cross-sectional views of a cutoff control mechanism according to the third embodiment. Figure 5A shows the closed state, and Figure 5B shows the cutoff state. As shown in Figures 5A and 5B, in a buckling prevention mechanism 60 according to the third embodiment, the installation position of the coil spring 32 and its surrounding structure are changed compared to the buckling prevention mechanism 50 according to the second embodiment.

[0050] The buckling prevention mechanism 60 of the third embodiment includes a cylindrical guide portion 61 that is inserted into the guide hole 35, a round shaft-shaped guide shaft 62 that is inserted into the guide portion 61, and a sliding portion 63 that is integrally formed with the lower end of the guide shaft 62.

[0051] The outer diameter of the guide portion 61 is set to be approximately the same as or slightly smaller than the inner diameter of the guide hole 35, and is provided so as to be freely displaceable up and down while inserted inside the guide hole 35. The lower end of the guide portion 61 is positioned so as to be aligned with the lower end of the guide hole 35 or so as to be slightly offset up and down from the lower end of the guide hole 35. The inner diameter of the guide portion 61 is set to be approximately the same as or slightly larger than the outer diameter of the guide shaft 62, and is provided so as to be freely displaceable up and down while the guide shaft 62 is inserted inside the guide portion 61. Thus, the guide portion 61 guides displacement of the guide shaft 62 in the vertical direction, which is the axial direction.

[0052] The guide shaft 62 is inserted inside the coil spring 32. The coil spring 32 with the guide shaft 62 inserted therethrough is sandwiched from above and below between the guide portion 61 and the sliding portion 63, and is kept in a charged state. In other words, the elastic force of the coil spring 32 presses the guide portion 61 upward and against the adjustment screw 36, and presses the sliding portion 63 downward and against the breaking latch 23.

[0053] The outer diameter of the guide shaft 62 is set to be approximately the same as or slightly smaller than the inner diameter of the coil spring 32, and with the guide shaft 62 inserted inside the coil spring 32, the two are able to move freely up and down relative to each other.

[0054] Like the sliding portion 52 of the second embodiment, the sliding portion 63 is formed in a curved shape with a semicircular cross section that bulges downward. The sliding portion 63 is in point contact or line contact with the upper end surface, which is the upper outer surface of the breaking latch 23, and presses against the upper end surface of the breaking latch 23 with the elastic force of the energized coil spring 32. Therefore, the sliding portion 63 transmits the elastic force of the coil spring 32 to the breaking latch 23.

[0055] In the third embodiment, when the breaking latch 23 is pivotally displaced from the locked position shown in Fig. 5A to the unlocked position shown in Fig. 5B, the sliding portion 63 and the guide shaft 62 are lifted and displaced upward by the breaking latch 23. At this time, the guide portion 61 guides the guide shaft 62 to displace parallel to the vertical direction, and a force is applied that pushes the guide shaft 62 upward without tilting it relative to the vertical direction, which is the extension direction of the central axis of the coil spring 32.

[0056] The action of this force causes the coil spring 32 to elastically deform so that its vertical length is shortened, thereby storing energy in the coil spring 32. During this elastic deformation, the guide shaft 62 is inserted inside the coil spring 32, so that deformation of the coil spring 32 in a direction bending relative to the direction in which the central axis extends is suppressed.

[0057] Furthermore, due to the rotational displacement of the breaking latch 23, the sliding portion 63 slides so that the contact position of the sliding portion 63 with respect to the upper end surface of the breaking latch 23 is displaced closer to the tip of the breaking latch 23. In other words, the formation of the sliding portion 63 prevents the sliding portion 63 and the guide shaft 62 from displacing in the left-right direction, and allows the sliding portion 63 to slide on the upper end surface (outer surface) of the turning breaking latch 23. As a result, when the coil spring 32 is energized, the lower end of the coil spring 32 abutting against the sliding portion 63 is displaced in the extension direction (up-down direction) of the central axis of the coil spring 32, which can prevent buckling, in which the coil spring 32 is deformed in a bending direction relative to the extension direction.

[0058] As described above, the buckling prevention mechanism 60 of the third embodiment can also prevent the coil spring 32 from buckling due to the rotation of the disconnecting latch 23.

[0059] In the third embodiment, a guide portion 61 is interposed like a spacer between the adjustment screw 36 and the coil spring 32. Therefore, according to the third embodiment as well, the upper end position of the coil spring 32 can be adjusted by vertically displacing the adjustment screw 36, thereby making it possible to adjust the elastic force exerted by the coil spring 32.

[0060] The present invention is not limited to the above-described embodiments, and various modifications can be made to the embodiments. In the above-described embodiments, the size, shape, orientation, etc. shown in the accompanying drawings are not limited to these, and can be modified as appropriate within the scope of the effects of the present invention. In addition, the present invention can be modified as appropriate without departing from the scope of the object of the present invention.

[0061] For example, the cutoff control mechanism 15 is not limited to the illustrated configuration example, and various modifications are possible, such as changing the shape and positional relationship of the lever portion 22 and the cutoff latch 23, as long as it can function in the same manner as the above-mentioned embodiments.

[0062] Furthermore, in each of the above embodiments, the upper portion of the guide hole 35 may be changed to a closed shape, and the adjustment screw 36 may be omitted. However, providing the adjustment screw 36 is advantageous in that the elastic force of the coil spring 32 can be adjusted, and the coil spring 32 or the like can be inserted from the upper portion of the guide hole 35 that is opened by removing the adjustment screw 36.

[0063] Furthermore, although the lower end sides of the sliding portions 52 and 63 are formed in a curved shape, they may be changed to other configurations that allow sliding with the breaking latch 23, such as a configuration in which rollers are provided. [Explanation of symbols]

[0064] 10: Circuit breaker 11: Open / close contact 12: Power transmission mechanism 13: Breaking spring 14: Opening and closing axis 15:Shut-off control mechanism 17: Movable contact 18: Fixed contact 22: Lever part 23:Shutoff latch 32: Coil spring 33: Buckling prevention mechanism 35: Guide hole 36: Adjustment screw 37: Spring holder 38: Connecting member 50: Buckling prevention mechanism 51: Spring holder 52: Sliding part 60: Buckling prevention mechanism 61: Information department 62: Guide shaft 63: Sliding part

Claims

1. a power transmission mechanism that drives the movable contact and the fixed contact, which constitute the switching contacts, in the direction of contacting and separating; a breaking spring capable of storing a driving force in a direction that separates the movable contact from the fixed contact via the power transmission mechanism; an opening / closing shaft connected to the power transmission mechanism; a cutoff control mechanism that controls the cutoff operation of the power transmission mechanism by the cutoff spring, The cutoff control mechanism includes a lever portion provided on the opening / closing shaft; a disconnection latch that restricts a disconnection operation of the power transmission mechanism at an engagement position where it engages with the lever portion, and that is rotated by a predetermined operation to a disengagement position where it releases the engagement with the lever portion, thereby starting the disconnection operation of the power transmission mechanism; a coil spring that exerts an elastic force to rotate the breaking latch from the unlocked position to the locked position; a buckling prevention mechanism that prevents the coil spring from deforming in a bending direction relative to the extension direction of the central axis when the breaking latch rotates from the locked position to the unlocked position.

2. The buckling prevention mechanism includes a guide hole through which the coil spring is inserted; a spring presser connected to one end of the coil spring and displaceable while being guided by an inner circumferential surface of the guide hole; a connecting member extending in a predetermined direction to connect the spring presser and the breaking latch, 2. The circuit breaker according to claim 1, wherein one end of the connecting member is connected to the spring presser so as to be relatively rotatable, and the other end of the connecting member is connected to the breaking latch so as to be relatively rotatable.

3. The buckling prevention mechanism includes a guide hole through which the coil spring is inserted; a spring presser connected to one end of the coil spring and displaceable while being guided by the inner circumferential surface of the guide hole; a sliding portion slidably provided on an outer surface of the breaking latch, 2. The circuit breaker according to claim 1, wherein the spring presser and the sliding portion are integrated to transmit the elastic force of the coil spring to the breaking latch.

4. The buckling prevention mechanism includes a guide shaft inserted into the coil spring; a guide portion that guides the axial displacement of the guide shaft; 2. The circuit breaker according to claim 1, further comprising a sliding portion that is integral with the guide shaft and slidably provided on the outer surface of the breaking latch, and that transmits the elastic force of the coil spring to the breaking latch.

5. 5. The circuit breaker according to claim 3, wherein the sliding portion has a curved surface shape that makes line contact or point contact with the breaking latch.

6. 4. The circuit breaker according to claim 2, further comprising an adjustment screw provided in the guide hole for adjusting the elastic force exerted by the coil spring.

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