CIRCUIT BREAKER

Abstract

 A compact and high-performance circuit breaker in which the force transfer efficiency of a switching mechanism unit is high is obtained. A circuit breaker according to the present invention has a link rotor engaged with a roller provided on the shaft of a rotor that holds a movable contactor; in the circuit breaker, when pivoting on the other end thereof due to the travel of a second link, the link rotor makes an engagement portion depress the roller while pivoting the roller so as to pivot the rotor, and a movable contact fixed to the movable contactor is made to make contact with or part from a fixed contact.

Description

Technical Field

[0001] The present invention relates to a circuit breaker such as a wiring breaker or a leakage breaker and particularly to the driving mechanism of a circuit breaker.

Background Art

[0002] For example, a conventional circuit breaker disclosed in Patent Document 1 has a so-called "single-pole double-throw"" operation mechanism in which two pairs of contacts consisting of a fixed contact and a movable contact are provided. Because this conventional circuit breaker is configured to be single-pole double-throw, the arc voltage thereof becomes twice as large as the arc voltage of a single-pole single-throw circuit breaker; in particular, the single-pole double-throw operation mechanism is suitable for a circuit breaker having a large breaking capacity. This conventional circuit breaker realizes the single-pole double-throw configuration in such a way that respective movable contacts are provided at both ends of apivotable movable contact carrier and in such a way that a power-source-side contact pedestal and a load-side contact pedestal having respective fixed contacts that each make contact with or part from the respective corresponding movable contacts are arranged in point symmetry with respect to the pivotal center of the movable contact carrier.

[0003] As a configuration characteristic of the single-pole double-throw method (referred to also as a "load active" method), as is clear from FIG. 1 of Patent Document 1, because when circuit breaking is implemented, air is exhausted toward the load (toward the right side in FIG. 1 of Patent Document 1), it is required to open the power-source-side movable contact in such a manner that the power-source-side movable contact parts from the bottom side of the case. Meanwhile, in general, it is required in a circuit breaker that in order to secure the contact reliability between the contacts, the force in a direction in which the contacts make contact with each other is larger than the force in which the contacts part from each other.

[0004] As a switching mechanism that satisfies these necessities, a toggle link mechanism configured with a main spring, an upper link, and a lower link is utilized in the circuit breaker disclosed in Patent Document 1. In this toggle linkmechanism, when the switchingmechanism unit drives the lower link of the toggle link mechanism, the force for pulling up the lower link from the bottom side of the circuit breaker, i.e., the force for pivoting the lower link in the OFF direction, which is the clockwise direction, may be relatively small; therefore, the force for depressing the lower link toward the bottom side, i.e. , the depressing force for pivoting the lower link in the ON direction, which is the counterclockwise direction, can be produced in a large scale. Here, the axis direction of the main spring in which the space efficiency is maximum is the perpendicular direction, as illustrated in FIG. 1 of Patent Document 1.

[0005] The conventional circuit breaker configured as described above has an advantage that when exhausting of air toward the load and the contact pressure between the contacts are taken into consideration, the foregoing arrangement and configuration enable the high reliability of the product to be obtained.

[Prior Art Reference]

[Patent Document 1]

[0006] 

[Patent Document 1] Japanese Patent Application Laid-Open No. H10-223115

Disclosure of the Invention

Problem(s) to be Solved by the Invention

[0007] However, the conventional circuit breaker disclosed in Patent Document 1 has problems that because the configuration and the size of the link mechanism of the switching mechanism unit is almost uniquely determined, the force transfer efficiency is low, the performance of the circuit breaker is deteriorated, and the circuit breaker becomes large.

[0008] The present invention has been implemented in order to solve the foregoing problems in those conventional apparatuses; the objective thereof is to obtain a compact and high-performance circuit breaker in which the force transfer efficiency of the switching mechanism unit is high.

Means for Solving the Problems

[0009] A circuit breaker according to the present invention includes a handle arm that is pivotably supported; a movable contactor having a movable contact on at least one end thereof; a fixed contactor having a fixed contact that makes contact with or parts from the movable contact; a rotor that is pivotably supported and holds the movable contactor; a shaft fixed on the rotor; a roller pivotably provided on the shaft; a lever that is pivotably supported and engaged with an latch of an overcurrent tripping device; a first link, one end of which is pivotably coupled with the lever; a second link, one end of which is pivotably coupled with the other end of the first link through a spring pin; a main spring, one end of which is fixed to the handle arm and the other end of which is fixed to the spring pin; and a link rotor, one end of which is pivotably coupled with the other end of the second link, the other end of which is pivotably supported, and that has an engagement portion, between the one end and the other end thereof, that is engaged with the roller. In the circuit breaker, when pivoting on the other end thereof due to a travel of the second link, the link rotor makes the engagement portion depress the roller while pivoting the roller so as to pivot the rotor, and the movable contactor is driven through pivoting of the rotor so that the movable contact makes contact with or parts from the fixed contact.

[0010] A circuit breaker according to the present invention includes a handle arm that is pivotably supported; a movable contactor having a movable contact on at least one end thereof; a fixed contactor having a fixed contact that makes contact with or parts from the movable contact; a rotor that is pivotably supported and holds the movable contactor; a rotor gear fixed on the rotor; a lever that is pivotably supported and engaged with an latch of an overcurrent tripping device; a first link, one end of which is pivotably coupled with the lever; a second link, one end of which is pivotably coupled with the other end of the first link through a spring pin; a main spring, one end of which is fixed to the handle arm and the other end of which is fixed to the spring pin; and a link rotor, one end of which is pivotably coupled with the other end of the second link, the other end of which is pivotably supported, and that has a link rotor gear engaged with the rotor gear. In the circuit breaker, when pivoting on the other end thereof due to a travel of the second link, the link rotor makes the rotor pivot through the link rotor gear and the rotor gear, and the movable contactor is driven through pivoting of the rotor so that the movable contact makes contact with or parts from the fixed contact.

Advantage of the Invention

[0011] In a circuit breaker according to the present invention, when pivoting on the other end thereof due to a travel of the second link, the link rotor makes the engagement portion depress the roller while pivoting the roller so as to pivot the rotor, and the movable contactor is driven through pivoting of the rotor so that the movable contact makes contact with or parts from the fixed contact; therefore, a compact and high-performance circuit breaker in which the force transfer efficiency of a switching mechanism unit is high can be obtained.

[0012] Moreover, in a circuit breaker according to the present invention, when pivoting on the other end thereof due to a travel of the second link, the link rotor makes the rotor pivot through the link rotor gear and the rotor gear, and the movable contactor is driven through pivoting of the rotor so that the movable contact makes contact with or parts from the fixed contact; therefore, a compact and high-performance circuit breaker in which the force transfer efficiency of a switching mechanism unit is high can be obtained.

Brief Description of the Drawings

[0013] 

FIG. 1 is a perspective view illustrating a circuit breaker according to Embodiment 1 of the present invention, when the cover thereof is removed;

FIG. 2 is a longitudinal cross-sectional view, taken at the center pole, of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the Trip mode;

FIG. 3 is a longitudinal cross-sectional view, taken at the center pole, of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the ON mode;

FIG. 4 is a longitudinal cross-sectional view, taken at the center pole, of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the OFF mode;

FIG. 5 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the Trip mode;

FIG. 6 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the ON mode;

[0014] 

FIG. 7 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the OFF mode;

FIG. 8 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 2 of the present invention, when the circuit breaker is in the ON mode;

FIG. 9 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 2 of the present invention, when the circuit breaker is in the OFF mode;

FIG. 10 is an explanatory graph representing the efficiency η of transfer of force from a link rotor to a rotor in a circuit breaker according to Embodiment 2 of the present invention;

FIG. 11 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 3 of the present invention, when the circuit breaker is in the ON mode; and

FIG. 12 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 3 of the present invention, when the circuit breaker is in the OFF mode.

Best Mode for Carrying Out the Invention

Embodiment 1

[0015] Hereinafter, a circuit breaker according to Embodiment 1 of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a perspective view illustrating a circuit breaker according to Embodiment 1 of the present invention, when the cover thereof is removed. FIG. 2 is a longitudinal cross-sectional view, taken at the center pole, of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the Trip mode. FIG. 3 is a longitudinal cross-sectional view, taken at the center pole, of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the ON mode. FIG. 4 is a longitudinal cross-sectional view, taken at the center pole, of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the OFF mode. FIG. 5 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the Trip mode. FIG. 6 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the ON mode. FIG. 7 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 1 of the present invention, when the circuit breaker is in the OFF mode. Acircuitbreaker, illustrated in FIGS. 1 through 7, according to Embodiment 1 of the present invention is a so-called "single-pole double-throw" type three-pole circuit breaker having two pairs of a fixed contact and a movable contact for each of the tree poles; however, in the following explanation, this three-pole circuit breaker will simply be referred to as a circuit breaker.

[0016] In FIGS. 1 through 7, the insulating case of a circuit breaker 101 is configured with a cover 1 (refer to FIG. 2) and a base 2A; on the base 2A, there are arranged a switching mechanism unit 51 having a manipulation handle 3, three double-throwunit cases 52 corresponding to the number of the poles, and an overcurrent tripping device 53. Because protruding from a handle window hole 1a (refer to FIG. 2) of the cover 1, the manipulation handle 3 can be operated in the ON or OFF direction; due to the positional relationship between the double-throw unit case 52 and the overcurrent tripping device 53, a power-source-side terminal 4 is disposed at the right side of each of the drawings and a load-side terminal 5 is disposed at the left side of each of the drawings.

[0017] As illustrated in FIG. 2, the double-throw unit case 52 includes, at both ends, a power-source-side fixed contactor 6 that is extended from the power-source-side terminal 4 and has a power-source-side fixed contact 7 at one end thereof, a load-side fixed contactor 12 that is connected with the load-side terminal 5 through the overcurrent tripping device 53 and has a load-side fixed contact 11 at one end thereof, a power-source-side movable contact 8 that makes contact with orparts from the power-source-side fixed contact 7, anda load-side movable contact 10 that makes contact with or parts from the load-side fixed contact 11; the double-throw unit case 52 also includes a movable contactor 9 held by a rotor 13 formed of, for example, a resin mold, an arc-extinction device 14 that cuts off an arc caused by separation between the power-source-side fixed contact 7 and the power-source-side movable contact 8, and an arc-extinction device 15 that cuts off an arc caused by separation between the load-side movable contact 10 and the load-side fixed contact 11.

[0018] The rotor 13 has a pair of contact pressure springs 32 for producing respective contact pressures between the power-source-side fixed contact 7 and the power-source-side movable contact 8 and between the load-side movable contact 10 and the load-side fixed contact 11. The rotor 13 can pivot on its pivotal center 13a (refer to FIGS. 5 through 7). Because being pivoted in conjunction with one another in accordance with the operation of the switching mechanism unit 51, the respective movable contactors 9 provided for the three poles are coupled with one another by means of a coupling shaft 25. The longitudinal cross-sectional view in FIG. 2 illustrates only the center pole out of the three poles.

[0019] Next, the configuration of the switching mechanism unit 51 will be explained. As illustrated in FIG. 1, as the switching mechanism unit 51, a frame 16 formed of a pair of frame plates 16A and 16B that face each other, an approximately U-shaped handle arm 17 that is pivotably supported by the frame 16, and the manipulation handle 3 adhered to the handle arm 17 are made into a unit. The handle arm 17 is pivotably supported on its pivotal axis.

[0020] As illustrated in FIG. 2, the unitized switching mechanism unit 51 includes a lever 19, one end 19b of which is formed to be able to engage with a latch 18 of the overcurrent tripping device 53 and the other end of which is pivotably supported by the frame 16 through a pivotal shaft 19a; an upper link 20, as a first link, one end of which is pivotably supported by the lever 19 through a pivotal shaft 20a; a lower link 21, as a second link, one end of which is pivotably supported by the other end of the upper link 20 through a spring pin 22; and a main spring 23, formed of an extension spring, a slave-side end 23a of which is supported by the spring pin 22 and a driving-side end 23b of which is supported by the handle arm 17. The upper link 20, the lower link 21, and the main spring 23 configure a toggle link mechanism.

[0021] The other end of the lower link 21 is pivotably coupled with one end of a link rotor 24 by means of a pin 24a. The link rotor 24 is provided with an elongate hole 24b between the one end and the other end thereof. A roller 27 is provided pivotably around the outer circumference of the coupling shaft 25 of the rotor 13, engaged with the inner wall of the elongate hole 24b of the link rotor 24, and can travel in the longitudinal direction of the elongate hole 24b along the inner wall of the elongate hole 24b. The other end of the link rotor 24 that approximately vertically bends toward the bottom of the drawing is pivotably supported by a pin 24c.

[0022] The elongate hole 24b of the link rotor 24 is engaged with the roller 27 that is coupled with the rotor 13 through the coupling shaft 25; thus, the movement of the lower link 21 is transferred to the rotor 13 through the link rotor 24, the roller 27, and the coupling shaft 25, so that the rotor 13 and the movable contactor 9 are pivoted.

[0023] Next, there will be explained the operation of the circuit breaker, configured as described above, according to Embodiment 1 of the present invention. Firstly, in the case of the OFF mode illustrated in FIGS. 4 and 7, the driving-side end 23b of the main spring 23 is situated more leftward in the drawing than the pivotal shaft 20a and the upper link 20 and the lower link 21 are bent, so that the lower link 21 is pulled upward in the drawing. Accordingly, the pulling force of the main spring 23 is exerted on the spring pin 22 in a direction in which the upper link 20 and the lower link 21a are kept bent. Therefore, the toggle mechanism formed of the upper link 20 and the lower link 21 is halted in the bending mode. In this situation, as well illustrated in FIG. 4, the movable contactor 9 supported by the rotor 13 is halted in the so-called OFF mode, while making the power-source-side movable contact 8 separated from the power-source-side fixed contact 7 and making the load-side movable contact 10 separated from the load-side fixed contact 11.

[0024] When the circuit breaker is in the OFF mode as illustrated in FIG. 4 or 7, pivoting of the manipulation handle 3 in the clockwise direction in the drawing makes the driving-side end 23b of the main spring 23 moves to the position of the ON mode as illustrated in FIG. 3 or 6, with respect to the pivotal shaft of the handle arm 17. In the foregoing moving process, the driving-side end 23b of the main spring 23 moves from the left side to the right side of the pivotal shaft 20a, so that the pulling force of the main spring 23 is exerted on the spring pin 22 rightward in the drawing. As a result, as well illustrated in FIG. 6, due to the pulling force of the main spring 23, the upper link 20 and the lower link 21 are aligned in a straight line, so that the lower link 21 travels from the position illustrated in FIG. 7 to the position illustrated in FIG. 6.

[0025] In the process where the lower link 21 travels from the position illustrated in FIG. 7 to the position illustrated in FIG. 6, the link rotor 24 pivots counterclockwise on the pin 24c; the inner wall of the elongate hole 24b depresses the roller 27 while pivoting it, and makes the rotor 13 pivot in the clockwise direction in the drawing through the coupling shaft 25. As a result, the movable contactor 9 supported by the rotor 13 pivots clockwise; then, as illustrated in FIG. 3, the movable contactor 9 comes into the so-called ON mode, while making the power-source-side movable contact 8 make contact with the power-source-side fixed contact 7 and making the load-side movable contact 10 make contact with the load-side fixed contact 11. In this situation the contact pressure springs 32 provided in the rotor 13 produce respective predetermined contact pressures between the power-source-side fixed contact 7 and the power-source-side movable contact 8 and between the load-side movable contact 10 and the load-side fixed contact 11.

[0026] In the ON mode illustrated in FIG. 3 or 6, the one end 19b of the lever 19 is engaged with the latch 18 of the overcurrent tripping device 53; the main spring 23 biases the lever 19 in the clockwise direction with respect to the pivotal shaft 19a, through the spring pin 22, the upper link 20, and the pivotal shaft 20a.

[0027] Next, When the circuit breaker is in the ON mode as illustrated in FIG. 3 or 6, pivoting of the manipulation handle 3 in the counterclockwise direction in the drawing makes the driving-side end 23b of the main spring 23 moves to the position of the OFF mode as illustrated in FIG. 4 or 7, with respect to the pivotal shaft of the handle arm 17. In the foregoing moving process, the driving-side end 23b of the main spring 23 moves from the right side to the left side of the pivotal shaft 20a, so that the pulling force of the main spring 23 is exerted on the spring pin 22 leftward in the drawing. As a result, as well illustrated in FIG. 7, the lower link 21 is pulled upward in the drawing and the upper link 20 pivots clockwise on the pivotal shaft 20a, so that the upper link 20 and the lower link 21 come into the bending mode.

[0028] In the process where the lower link 21 travels from the position illustrated in FIG. 6 to the position illustrated in FIG. 7, the link rotor 24 pivots clockwise on the pin 24c; the inner wall of the elongate hole 24b pulls up the roller 27 while pivoting it, and makes the rotor 13 pivot in the counterclockwise direction in the drawing through the coupling shaft 25. As a result, the movable contactor 9 supported by the rotor 13 pivots counterclockwise; then, as illustrated in FIG. 4, the movable contactor 9 comes into the so-called OFF mode, while making the power-source-side movable contact 8 separated from the power-source-side fixed contact 7 and making the load-side movable contact 10 separated from the load-side fixed contact 11. At this time, respective arcs are produced between the power-source-side fixed contact 7 and the power-source-side movable contact 8 and between the load-side movable contact 10 and the load-side fixed contact 11; however, these arcs are extinguished by the arc-extinction devices 14 and 15.

[0029] In the ON mode as illustrated in FIG. 3 or 6, when an overcurrent or the like is sensed and the overcurrent tripping device 53 operates, a trip bar 26 (refer to FIG. 1) responds to the operation of the overcurrent tripping device 53 and the latch 18 pivots in the clockwise direction in the drawing, so that the engagement between the latch 18 and the one end 19b of the lever 19 is released. As described above, the main spring 23 biases the lever 19 in the clockwise direction in the drawing with respect to the pivotal shaft 19a; therefore, when the engagement between the latch 18 and the one end 19b of the lever 19 is released, the lever 19 starts to pivot clockwise on the pivotal shaft 19a. Due to the foregoing pivoting, the pivotal shaft 20a that couples the upper link 20 with the lever 19 travels rightward in the drawing with respect to the driving-side end 23b of the main spring 23. As a result, the toggle link mechanism consisting of the upper link 20 and the lower link 21 is bent; due to the biasing force of the spring pin 22, the lower link 21 is pulled upward from the position illustrated in FIG. 3 or 6 and travels to the position of the Trip mode illustrated in FIG. 2 or 5.

[0030] In the process where the lower link 21 travels as described above, the link rotor 24 pivots clockwise on the pin 24c; the inner wall of the elongate hole 24b pulls up the roller 27 while pivoting it, and makes the rotor 13 pivot in the counterclockwise direction in the drawing through the coupling shaft 25. As a result, the movable contactor 9 supported by the rotor 13 pivots counterclockwise; then, as illustrated in FIG. 2, the movable contactor 9 comes into the so-called Trip mode, while making the power-source-side movable contact 8 separated from the power-source-side fixed contact 7 and making the load-side movable contact 10 separated from the load-side fixed contact 11. At this time, respective arcs are produced between the power-source-side fixed contact 7 and the power-source-side movable contact 8 and between the load-side movable contact 10 and the load-side fixed contact 11; however, these arcs are extinguished by the arc-extinction devices 14 and 15.

[0031] As described above, in the circuit breaker according to Embodiment 1 of the present invention, the operation of the link rotor 24 that is driven by the toggle link mechanism consisting of the upper link 20, the lower link 21, and the main spring 23 is transferred to the rotor 13 through the roller 27 and the coupling shaft 25, so that the ON operation, the OFF operation, and the Trip operation of the circuit breaker are realized. Because the force transfer between the link rotor 24 and the rotor 13 is performed by means of rolling contact between the roller 27 and the inner wall of the elongate hole 24b of the link rotor 24, the friction coefficient becomes extremely small, whereby the transfer efficiency is raised.

[0032] In addition, by utilizing a bearing instead of the roller 27, the friction coefficient can further be reduced, whereby the transfer efficiency is further be raised.

[0033] As described above, the circuit breaker according to Embodiment 1 of the present invention makes it possible to realize small-friction-coefficient and efficient operation can be realized; therefore, there can be obtained easy-to-use, compact, and high-performance circuit breakers such as a molded case circuit breaker and an earth leakage circuit breaker.

Embodiment 2

[0034] Next, a circuit breaker according to Embodiment 2 of the present invention will be explained. FIG. 8 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 2 of the present invention, when the circuit breaker is in the ON mode. FIG. 9 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 2 of the present invention, when the circuit breaker is in the OFF mode.

[0035] In FIGS. 8 and 9, the link rotor 24 is formed to be approximately linear; one end thereof is pivotably coupled with the other end of the lower link 21 by means of the pin 24a, and the other end thereof is pivotably supported by the pin 24c. Here, letting X denote the direction in which the longitudinal-direction sidewall of the elongate hole 24b formed in the link rotor 24 extends, i.e., the direction in which the roller 27 travels, and letting Y denote the direction of a line between the pivotal center 13a of the rotor 13 and the center of the roller 27, the angle between the direction X and the direction Y is kept at an after-mentioned value when the circuit breaker is in the ON mode as illustrated in FIG. 8. In contrast, in the case where the circuit breaker is in the OFF mode as illustrated in FIG. 9, the direction X and the direction Y coincide with each other and the angle θ between them becomes approximately "0".

[0036] FIG. 10 is an explanatory graph representing the efficiency η of transfer of force from a link rotor to a rotor in a circuit breaker according to Embodiment 2 of the present invention. In FIG. 10, the abscissa denotes the angle θ between X and Y, and the ordinate denotes the transfer efficiency η of the force that is transferred from the link rotor 24 to the rotor 13. Letting FL denote force exerted on the link rotor 24 and letting FR denote force exerted on the roller 13, the transfer efficiency η is given by the equation (1) below.

[0037] As illustrated in FIG. 10, in the relationship between the transfer efficiency η of the force transferred from the link rotor 24 to the rotor 13 and the angle θ between the direction X and the direction Y, when the angle θ is 0 [deg], the transfer efficiency η is "1", and when the angle θ is 90 [deg], the transfer efficiency η is "0" . As the angle θ changes from 0 [deg] to 90 [deg], the transfer efficiency η changes in such a way as represented by the solid line.

[0038] Here, when the angle θ changes in the range from 0 [deg] to 45 [deg], η is the same as or larger than 70 [%] (Region B); when the angle θ changes in the range from 0 [deg] to 30 [deg], η is the same as or larger than 87 [%] (Region A). Accordingly, by selecting the direction in which the roller 27 travels in the elongate hole 24b, i.e. , by selecting the position of the pivotal center 13a of the rotor 13 in such a way that the angle θ becomes the same as or smaller than 45 [deg] or preferably the same as or smaller than 30 [deg], the force can efficiently be transferred from the link rotor 24 to the rotor 13.

[0039] The circuit breaker according to Embodiment 2 of the present invention is set in such a way that when the circuit breaker is in the ON mode as illustrated in FIG. 8, θ = 45 [deg] and in such a way that when the circuit breaker is in the OFF mode as illustrated in FIG. 9, θ = 0 [deg]. Therefore, the transfer efficiency η is always the same as or larger than 70 [%].

[0040] When the circuit breaker is in the OFF mode as illustrated in FIG. 9 and the manipulation handle 3 is made to pivot in the clockwise direction in the drawing, the lower link 21 depresses the one end of the link rotor 24 downward in the drawing, as explained in Embodiment 1; then, the link rotor 24 pivots counterclockwise on the pin 24c. As a result, the roller 27 engaged with the elongate hole 24b of the link rotor 24 is depressed while sliding in the elongate hole 24b, so that the rotor 13 pivots clockwise in the drawing. The clockwise pivoting of the rotor 13 makes the movable contactor 9 pivot clockwise, so that the circuit breaker comes into the ON mode as illustrated in FIG. 8.

[0041] When the circuit breaker is in the ON mode as illustrated in FIG. 8 and the manipulation handle 3 is made to pivot counterclockwise in the drawing, the link rotor 24 is pulled upward in the drawing, contrary to what has been described above; the link rotor 24 pivots clockwise on the pin 24c; the biasing force of the main spring 23 is transferred to the roller 27 through the inner wall of the elongate hole 24b of the link rotor 24; then, the rotor 13 pivots counterclockwise in the drawing, whereby the circuit breaker comes into the OFF mode as illustrated in FIG. 2. The other configurations and operations are the same as those in Embodiment 1.

[0042] In the foregoing circuit breaker according to Embodiment 2 of the present invention, it is made possible to raise the transfer efficiency η of the force that is transferred from the link rotor 24 to the rotor 13; thus, there can be obtained an easy-to-use, compact, and high-performance circuit breaker such as a molded case circuit breaker or an earth leakage circuit breaker.

Embodiment 3

[0043] Next, a circuit breaker according to Embodiment 3 of the present invention will be explained. FIG. 11 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 3 of the present invention, when the circuit breaker is in the ON mode. FIG. 12 is a side view, taken at the center pole, of the switching mechanism unit of a circuit breaker according to Embodiment 3 of the present invention, when the circuit breaker is in the OFF mode.

[0044] In FIGS. 11 and 12, the link rotor 24 is formed to be approximately linear; one end thereof is pivotably coupled with the other end of the lower link 21 by means of the pin 24a, and the other end thereof is pivotably supported by the pin 24c. A link rotor gear 24g is formed integrally with the link rotor 24. The link rotor gear 24g may be formed separately from the link rotor 24 and fixed to the link rotor 24.

[0045] A rotor gear 13g is formed integrally with the rotor 13. The rotor gear 13g may be formed separately from the rotor 13 and fixed to the rotor 13. The rotor gear 13g and the link rotor gear 24g are engaged and coupled with each other.

[0046] When the circuit breaker is in the OFF mode as illustrated in FIG. 12 and the manipulation handle 3 is made to pivot in the clockwise direction in the drawing, the lower link 21 depresses the one end of the link rotor 24 downward in the drawing, as explained in Embodiment 1; then, the link rotor 24 and the link rotor gear 24g pivot counterclockwise on the pin 24c. As a result, the rotor gear 13g coupled with the link rotor gear 24g pivots clockwise in the drawing along with the rotor 13. The clockwise pivoting of the rotor 13 makes the movable contactor 9 pivot clockwise, so that the circuit breaker comes into the ON mode as illustrated in FIG. 11.

[0047] When the circuit breaker is in the ON mode as illustrated in FIG. 11 and the manipulation handle 3 is made to pivot counterclockwise in the drawing, the link rotor 24 is pulled upward in the drawing, contrary to what has been described above; the link rotor 24 pivots clockwise on the pin 24c; the biasing force of the main spring 23 is transferred to the rotor gear 13g through the link rotor gear 24g; then, the rotor 13 pivots counterclockwise in the drawing, whereby the circuit breaker comes into the OFF mode as illustrated in FIG. 12. The other configurations and operations are the same as those in Embodiment 1 or 2.

[0048] In the foregoing circuit breaker according to Embodiment 3 of the present invention, the gears make it possible to efficiently transfer the force that is transferred from the link rotor 24 to the rotor 13; thus, there can be obtained an easy-to-use, compact, and high-performance circuit breaker such as a molded case circuit breaker or an earth leakage circuit breaker.

Industrial Applicability

[0049] A circuit breaker according to the present invention canbe applied to the fields of a molded case circuit breaker, an earth leakage circuit breaker, and the like.

Description of Reference Numerals

[0050] 

2A:

base

6:

power-source-side fixed contactor

7:

power-source-side fixed contact

8:

power-source-side movable contact

9:

movable contactor

10:

load-side movable contact

11:

load-side fixed contact

12:

load-side fixed contactor

13:

rotor

16:

frame

17:

handle arm

18:

latch

19:

lever

20:

upper link

21:

lower link

22:

spring pin

23:

main spring

24:

link rotor

25:

coupling shaft

26:

trip bar

27:

roller

29:

cross bar

51:

switching mechanism unit

52:

double-throw unit case

53:

overcurrent tripping device

101:

circuit breaker

Claims

1. A circuit breaker comprising:

a handle arm that is pivotably supported;

a movable contactor having a movable contact on at least one end thereof;

a fixed contactor having a fixed contact that makes contact with or parts from the movable contact;

a rotor that is pivotably supported and holds the movable contactor;

a shaft fixed on the rotor;

a roller pivotably provided on the shaft;

a lever that is pivotably supported and engaged with an latch of an overcurrent tripping device;

a first link, one end of which is pivotably coupled with the lever;

a second link, one end of which is pivotably coupled with the other end of the first link through a spring pin;

a main spring, one end of which is fixed to the handle arm and the other end of which is fixed to the spring pin; and

a link rotor, one end of which is pivotably coupled with the other end of the second link, the other end of which is pivotably supported, and that has an engagement portion, between the one end and the other end thereof, that is engaged with the roller, wherein when pivoting on the other end thereof due to a travel of the second link, the link rotor makes the engagement portion depress the roller while pivoting the roller so as to pivot the rotor; and the movable contactor is driven through pivoting of the rotor so that the movable contact makes contact with or parts from the fixed contact.

2. The circuit breaker according to claim 1, wherein the engagement portion includes a sliding groove formed in the link rotor; and the roller can pivot while making contact with an inner wall of the sliding groove and can travel along the inner wall of the sliding groove.

3. The circuit breaker according to any one of claims 1 and 2, wherein the angle between the direction in which the inner wall of the sliding groove extends and the direction of a line between the pivotal center of the rotor and the pivotal center of the roller is the same as or smaller than 45 [deg] when switching operation is implemented through the handle arm.

4. A circuit breaker comprising:

a handle arm that is pivotably supported;

a movable contactor having a movable contact on at least one end thereof;

a fixed contactor having a fixed contact that makes contact with or parts from the movable contact;

a rotor that is pivotably supported and holds the movable contactor;

a rotor gear fixed on the rotor;

a lever that is pivotably supported and engaged with an latch of an overcurrent tripping device;

a first link, one end of which is pivotably coupled with the lever;

a second link, one end of which is pivotably coupled with the other end of the first link through a spring pin;

a main spring, one end of which is fixed to the handle arm and the other end of which is fixed to the spring pin; and

a link rotor, one end of which is pivotably coupled with the other end of the second link, the other end of which is pivotably supported, and that has a link rotor gear engaged with the rotor gear, wherein when pivoting on the other end thereof due to a travel of the second link, the link rotor makes the rotor pivot through the link rotor gear and the rotor gear; and the movable contactor is driven through pivoting of the rotor so that the movable contact makes contact with or parts from the fixed contact.

Drawing