EP1939903A1

EP1939903A1 - Switching mechanism for air circuit breaker and toggle links thereof

Info

Publication number: EP1939903A1
Application number: EP07023461A
Authority: EP
Inventors: Sang-Chul Lee; Ki-Hwan Kim; Hong-Ik Yang; Kil-Young Ahn
Original assignee: LS Industrial Systems Co Ltd
Current assignee: LS Electric Co Ltd
Priority date: 2006-12-29
Filing date: 2007-12-04
Publication date: 2008-07-02
Anticipated expiration: 2027-12-04
Also published as: KR20080002431U; RU2376670C2; MY153222A; EP1939903B1; RU2007149529A; CN101211720B; ES2345362T3; KR200442291Y1; CN101211720A; DE602007006405D1

Abstract

Disclosed are a switching mechanism for an air circuit breaker, and toggle links thereof capable of preventing interference or collision therebetween while the air circuit breaker performs a closing operation and an opening operation. The toggle links comprise: a first link (29) configured to be rotatable; a second link (34) having one end connected to the first link, rotatable by a discharging elastic energy of a closing spring, and having one pair of extension portions (55) extended towards the first link so as to prevent interference with the first link by interposing the first link therebetween; and a third link (35) having one end connected to the second link, and rotated together with the second link, for moving the movable contactor to the closing position.

Description

RELATED APPLICATION

The present disclosure relates to subject matter contained in priority Korean Application No. 20-2006-0033041, filed on December 29, 2006 , which is herein expressly incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a switching mechanism for an air circuit breaker and toggle links thereof, and more particularly, to a switching mechanism for an air circuit breaker capable of enhancing operational reliability by preventing interference between links, and toggle links thereof.

2. Description of the Background Art

Generally, an air circuit breaker serves as a low voltage type circuit beaker that performs a turning on/off of load circuit or a circuit breaking operation in the occurrence of an abnormal current such as a short circuit, a ground fault, and an excess current.
In the conventional air circuit breaker, toggle links may be deformed or damaged due to an uneven assembled state therebetween, or due to collision or interference between side surfaces thereof at the time of a charging operation by a closing spring and a closing operation.
As the toggles links are deformed and damaged, deviation severely occurs between opening and closing operations of the air circuit breaker. Due to unbalance in a three-phase current and a voltage supplied to a load when the air circuit breaker performs opening and closing operations, the load is overheated or damaged. Furthermore, the life-span of the air circuit breaker is lowered.

SUMMARY OF THE INVENTION

Therefore, an object of the present disclosure is to provide a switching mechanism for an air circuit breaker capable of enhancing operational reliability by preventing damage or deformation of toggle links due to interference therebetween, and toggle links thereof.
To achieve these and other advantages and in accordance with the purpose of the present disclosure, as embodied and broadly described herein, there is provided a switching mechanism for an air circuit breaker, comprising:

a stationary contactor connected to a power source side circuit or a load side circuit for each phase, and provided according to each phase;
a movable contactor disposed to correspond to the stationary contactor, and movable to a closing position for contacting the stationary contactor, or an opening position for being separated from the stationary contactor;
a main shaft configured to be rotatable, for providing a driving force to move the movable contactor to the closing position or the opening position;
a main shaft lever coaxially disposed on the main shaft, and having one end connected to the movable contactor;
a closing spring for providing a driving energy to move the movable contactor to the closing position;
a driving lever connected to the closing spring, and rotatable by the driving energy provided from the closing spring;
a first link configured to be rotatable, and having one end connected to the driving lever so as to interlock therewith;
a second link connected to the first link, rotatable by contacting the driving lever being rotated, having two plate members, and having an extension portion to prevent interference with the first link by disposing the first link between the two plate members;
and a third link having one end connected to the second link, having another end connected to the main shaft lever, and rotated together with the second link so as to move the movable contactor to the closing position, for rotating the main shaft lever.

To achieve these and other advantages and in accordance with the purpose of the present disclosure, as embodied and broadly described herein, there is also provided toggle links of a switching mechanism for an air circuit breaker, comprising:

a first link configured to be rotatable;
a second link having one end connected to the first link, rotatable by a discharging elastic energy of a closing spring, and having one pair of extension portions extended to prevent interference with the first link by disposing the first link therebetween; and
a third link having one end connected to the second link, and rotated together with the second link, for moving the movable contactor to the closing position.

The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:

FIG. 1 is a sectional view of a switching mechanism for an air circuit breaker according to the present invention;
FIG. 2 is a sectional view showing a compressed state of a closing spring of the switching mechanism for an air circuit breaker according to the present invention;
FIG. 3 is a sectional view showing a closed-circuit state of the switching mechanism for an air circuit breaker according to the present invention; and
FIG. 4 is a perspective view showing toggle links of the switching mechanism for an air circuit breaker according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.
Hereinafter, a switching mechanism for an air circuit breaker according to the present invention, and toggle links thereof will be explained in more detail with reference to the attached drawings.
As shown in FIGS. 1 to 3, a switching mechanism 2 for an air circuit breaker according to the present invention comprises a stationary contactor 39, a movable contactor 38, a main shaft 3, a main shaft lever 40, a closing spring 25, a driving lever 24, toggle links 29, 34 and 35.
The toggle links 29, 34 and 35 are referred to as first, second, and third links, respectively.
The stationary contactor 39 is connected to a power source side circuit or a load side circuit in each of three phases such as R, S and T, and is disposed according to each phase. When the air circuit breaker is implemented as an air circuit breaker for a three-phase alternating current of R, S and T, the stationary contactor 39 is disposed according to each phase.
The movable contactor 38 is disposed so as to correspond to the stationary contactor 39. That is, when three stationary contactors 39 are provided, three movable contactors 38 are provided. The movable contactor 38 is movable to a closing position to contact the stationary contactor 39, or to an opening position to be separated from the stationary contactor 39.
The main shaft 3 is rotatable so as to provide a driving force to move the plurality of movable contactors (i.e., three movable contactors) simultaneously to the closing position or the opening position.
The main shaft lever 40 is coaxially disposed on the main shaft 3, and has one end connected to the movable contactor.
The closing spring 25 provides a driving energy to drive the movable contactor 38 to the closing position.
The driving lever 24 is connected to the closing spring 25, and is rotatable by the driving energy from the closing spring 25.
The first link 29 is rotatable, and one end thereof is connected to the driving lever 24 so as to interlock therewith.
The second link 34 is rotatable by interlocking with the first link 29, and includes two plate members 34a and 34b. The second link 34 has an extension portion 55 extended so as to prevent interference with the first link 29 by positioning the first link 29 between the plate members 34a and 34b. The extension portion 55 is composed of one pair of extension portions 55a and 55b disposed at the plate members 34a and 34b, respectively.
The third link 35 has one end connected to the second link 34, and the other end connected to the main shaft lever 40. The third link 35 is rotated together with the second link 34 so as to drive the movable contactor 38 to the closing position, thereby rotating the main shaft lever 40.
As shown in FIGS. 1 to 3, the switching mechanism 2 for an air circuit breaker according to the present invention further comprises a rotation shaft 21, a cam 22, one pair of side plates 9, a first latch 27, an on-lever 28, a latch roller 30, a second latch 31, an off-lever 32, a connecting shaft 36, an opening spring 37, and a lower terminal 39-1.
The cam 22 is installed on the rotation shaft 21 thus to be rotated manually or automatically. Namely, the rotation shaft 21 is connected to a manual handle or a motor (not shown) thus to be manually rotated or to be electrically driven.
One pair of side plates 9 supports the switching mechanism 2 at both sides.
The driving lever 24 is rotatably supported between the two side plates 9, and is rotated by interlocking with the first link 29 coaxially installed with the cam 22 and the rotation shaft 21.
One end of the closing spring 25 is supported by a spring seat (not shown), and the other end thereof is supported by a spring support bracket (not shown). The spring seat is connected to a lower end of the driving lever 24, and the spring support bracket is fixedly installed at the side plates 9. The driving lever 24 is rotated as the cam 22 rotates, and thus the spring seat is moved in the left direction of FIGS. 1 to 3. Here, the closing spring 25 is compressed by the spring seat being moved in the left direction, thereby charging an elastic energy.
The first latch 27 is extended in upper and lower directions, and is biased so as to elastically rotate in one direction by a spring (a reference numeral not designated) connected between a pin fixed to the side plate 9 and the first latch 27. In order to prevent rotation of the cam 22 occurred while the elastic energy of the closing spring 25 charged at the time of the charging operation is discharged, the first latch 27 latches or locks the cam 22 by contacting thereto.
The on-lever 28 is rotatably installed above the first latch 27 so as to lock or release the first latch 27.
The first link 29 has an 'L' shape, and is rotatable centering around a central shaft (not shown) fixedly installed at the side plate 9. A lower horizontal extension portion of the first link 29 is connected to the second link 34. A groove 49 for getting in or getting out a latch roller 30 of the second latch 31 so as to lock or release the first link 29 is formed at an upper end of the first link 29.
The second latch 31 is disposed above the first link 29 with a nearly 'V' shape. The latch roller 30 is rotatably installed at a central portion of the second latch 31 in a length direction. The second latch 31 is biased so as to rotate in one direction by a bias spring (a reference numeral not designated) connected between a pin (a reference numeral not designated) fixed to the side plate and the second latch 31. Accordingly, when the latch roller 30 gets into the groove 49 of the first link 29, the second latch 31 is locked by the first link 29. On the contrary, when the latch roller 30 is drawn out (gets out) of the groove 49 of the first link 29, the second latch 31 is released thus to rotate by the bias spring in one direction , i.e., a counterclockwise direction in FIGS. 1 to 3.
The off-lever 32 is disposed above the second latch 31, and is rotatable centering around a central shaft fixed to the side plate 9. The off-lever 32 is rotatable to a position to lock the second latch 31 or to release the locking of the second latch 31. As means to rotate the off-lever 32, there may be provided an off-button operated by a user's pressing, and an off-coupling connected between the off-button and the off-lever 32 so as to transmit a displacement of the off-button to the off-lever 32. The off-button and the off-coupling were not shown.
A lower end of the second link 34 is connected to the driving lever 24 so as to interlock therewith together with the first link 29. The second link 34 comes in contact with a pin 33 provided at the driving lever 24, and one side surface thereof is pushed by the pin 33.
The third link 35 is connected to an upper end of the second link 34, and is rotatable together with the second link 34 according to a displacement of the second link 34.
The main shaft 3 is extended to penetrate the side plate 9. The main shaft lever 40 is connected to the third link 35, and is installed on the main shaft 3 so as to rotate together with the main shaft 3. Accordingly, as the third link 35 rotates clockwise or counterclockwise, the main shaft lever 40 rotates counterclockwise or clockwise, and thus the main shaft 3 rotates counterclockwise or clockwise.
The connecting shaft 36 serves to connect the third link 35 to the main shaft 3 for interlocking therebetween.
One end of the opening spring 37 is supported by the connecting shaft 36, and the other end thereof is supported by one fixing pin (a reference numeral not designated) fixed onto the side plate 9. Referring to FIG. 3, the main shaft lever 40 rotates counterclockwise in the closing position of the air circuit breaker, and thus the connecting shaft 36 is moved to the left side in drawing (i.e., towards the stationary contactor 39). Accordingly, the opening spring 37 is extended to charge an elastic energy. Under this state, when the off-button is pressed by a user, the off-lever 32 rotates clockwise as shown in FIG. 1 to release the second latch 31. Accordingly, the second latch 31 rotates counterclockwise in drawing, and the latch roller 30 is drawn out of the groove 49 of the first link 29. Here, the main shaft lever 40 and the main shaft 3 rotate counterclockwise by discharging the elastic energy of the opening spring 37, and thus the third link 35 and the second link 34 rotate clockwise.
The main shaft lever 40 is coaxially connected onto the main shaft 3 so as to rotate together therewith and is connected with the movable contactor 38. When the main shaft lever 40 is rotated counterclockwise, the movable contactor 38 is separated from the stationary contactor 39 following the main shaft lever 40 to implement an open- circuit. On the contrary, when the main shaft lever 40 rotates clockwise on the drawing, the movable contactor 38 is moved to contact the stationary contactor 39 following the main shaft lever 40. Accordingly, a closed circuit is formed between the power source and the load thus to flow a current.
The lower terminal 39-1 is connected to the movable contactor 38 through an electric conductor (not shown), and is electrically connected to the load or the power source. Accordingly, when the movable contactor 38 comes in contact with the stationary contactor 39, a closed-circuit is implemented between the power source and the load thus to flow a current. On the contrary, when the movable contactor 38 is separated from the stationary contactor 39, an open-circuit is implemented between the power source and the load thus to prevent a current flow.
The toggle links of the switching mechanism for an air circuit breaker according to the present invention will be explained in more detail with reference to FIG. 4.
As shown in FIG. 4, the toggle links of the switching mechanism for an air circuit breaker according to the present invention perform a toggling operation to endure a repulsive load occurred at the time of a closing operation. The toggle links include the first link 29, the second link 34, and the third link 35.
The first and second links 29 and 34 are connected to each other by a first connection pin 41, and the second and third links 34 and 35 are connected to each other by a second connection pin 42 fixed to the third link 35. Referring to FIGS. 1 to 3, the first connection pin 41 is extended to be connected up to the driving lever 24, thereby connecting the first and second links 29 and 34 to the driving lever 24 for interlocking with the driving lever 24.
In order to prevent the first and second links 29 and 34 from colliding to each other by an interference at the time of a closing operation and an opening operation of the air circuit breaker, the second link 34 includes a first plate member 34a and a second plate member 34b. Also, the first plate member 34a and the second plate member 34b are disposed to be separated from each other by a predetermined distance therebetween. Also, the first link 29 is disposed between the first plate member 34a and the second plate member 34b. The reference numeral 52 denotes a side surface of the first link 29 facing the second link 34 in a thickness direction.
Despite the above configuration, the first and second links 29 and 34 may collide with each other while the air circuit breaker is operated, due to the following reasons, such as an assembly error and an uneven load at the time of a charging operation for the closing spring, a closing operation, or an opening operation.
In order to prevent the first and second links 29 and 34 from colliding to each other by interference at the time of a charging operation for the closing spring, a closing operation, or an opening operation, the second link 34 is provided with an extension portion 55 extended towards the first link 29 and allowing the first link 29 to be disposed between the first plate member 34a and the second plate member 34b. The extension portion 55 is composed of an extension portion 55a of the first plate member 34a, and an extension portion 55b of the second plate member 34b.
The extension portion 55 of the second link 34 maintains an interposed state of the first link 29 between the first and second links 34a and 34b when the air circuit breaker is operated to charging, closing, and opening, thereby preventing interference or collision between the first and second links 29 and 34.
The switching mechanism 2 for the air circuit breaker according to the present invention performs a charging operation, a closing operation, and an opening operation. More concretely, the switching mechanism 2 performs a charging operation for charging an elastic energy to the closing spring 25, a closing operation for contacting the movable contactor 38 to the stationary contactor 39 by using the elastic energy charged to the closing spring 25, and an opening operation for separating the movable contactor 38 from the stationary contactor 39 by using the elastic energy charged to the opening spring 37.
With reference to FIG. 2, will be explained the operation for charging the closing spring 25 of the air circuit breaker so as to perform a closing operation under a state that the movable contactor 38 has been separated from the stationary contactor 39. As shown in FIG. 2, the rotation shaft 21 is rotated counterclockwise by manually operating a handle (not shown) provided at the rotation shaft 21 by a user, or by automatically operating the rotation shaft 21 by a motor (not shown) connected thereto. Accordingly, the cam 22 is rotated counterclockwise, and thus the first link 29 coaxially connected with the cam 22 and the rotation shaft 21 is rotated. Under this state, the driving lever 24 connected with one end of the first link 29 compresses the closing spring 25 through the spring seat (not shown) while being rotated. Accordingly, an elastic energy for a closing operation is charged to the closing spring 25.
Hereinafter, a closing operation of the air circuit breaker will be explained with reference to FIG. 3.
When a user presses a closing button (not shown), the on-lever 28 interlock connected to the closing button is rotated counterclockwise. Accordingly, the first latch 27 is released, and is rotated in one direction by a bias spring supported at the side plate 9. As a result, the locked state of the cam 22 by the first latch 27 is released. By a discharge elastic energy of the closing spring 25, the driving lever 24 is rotated counterclockwise. Accordingly, the first link 29 having one end connected to the driving lever 24 is rotated counterclockwise, and thus the second and third links 34 and 35 are rotated counterclockwise. Under this state, the main shaft lever 40 is rotated clockwise, and thus the movable contactor 38 connected to the main shaft lever 40 comes in contact with the stationary contactor 39. As a result, the closing operation of the air circuit breaker is completed.
During the closing operation, the closing spring 37 is extended as the connecting shaft 36 provided at the main shaft lever 40 is moved in the left direction, thereby charging an elastic energy for the closing operation.
Next, an opening operation of the air circuit breaker will be explained with reference to FIG. 1.
When a user presses the off-button, the off-lever 32 is rotated clockwise as shown in FIG. 1 to release the second latch 31. Accordingly, the second latch 31 is rotated counterclockwise, and the latch roller 30 is drawn out of the groove 49 of the first link 29. Here, the main shaft lever 40 and the main shaft 3 are rotated counterclockwise by the discharge elastic energy of the opening spring 37, and thereby the second and third links 34 and 35 are rotated clockwise. Accordingly, the movable contactor 38 connected to the main shaft lever 40 is separated from the stationary contactor 39, thereby implementing an open-circuit between the power source and the load.
During the charging operation, the closing operation, and the opening operation, the first, second, and third links 29, 34 and 35 perform a toggling operation. Since the extension portions 55a and 55b of the second link 34 are located so as to interpose the first link 29 therebetween, an uneven assembled state among the toggle links 29, 34 and 35 is prevented, and interference or collision between the first and second links 29 and 34 while the air circuit breaker is operated is prevented.
In the air circuit breaker according to the present invention, the second link 34 comprises a pair of plate members, and the extension portions disposed at each end of the plate members and extended to locate the first link 29 between the plate members. Accordingly, while the air circuit breaker is operated, interference or collision between the first and second links 29 and 34 is prevented thus to prevent deformation or damage of the toggle links. As a result, the air circuit breaker has an enhanced reliability and a long life-span.
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments.
As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims

A switching mechanism for an air circuit breaker, comprising:
a stationary contactor connected to a power source side circuit or a load side circuit for each phase, and provided according to each phase;

a movable contactor disposed to correspond to the stationary contactor, and movable to a closing position for contacting the stationary contactor, or an opening position for being separated from the stationary contactor;

a main shaft configured to be rotatable, for providing a driving force to move the movable contactor to the closing position or the opening position;

a main shaft lever coaxially disposed on the main shaft, and having one end connected to the movable contactor;

a closing spring for providing a driving energy to move the movable contactor to the closing position;

a driving lever connected to the closing spring, and rotatable by the driving force provided from the closing spring;

a first link configured to be rotatable, and having one end connected to the driving lever for interlocking therewith;

a second link rotatable by interlocking with the first link, having two plate members, and having an extension portion towards the first link so as to prevent interference with the first link by interposing the first link between the two plate members; and

a third link having one end connected to the second link, having the other end connected to the main shaft lever, and rotated together with the second link so as to move the movable contactor to the closing position, for rotating the main shaft lever.
Toggle links of a switching mechanism for an air circuit breaker, comprising:
a first link configured to be rotatable;

a second link having one end connected to the first link, rotatable by a discharging elastic energy of a closing spring, and having a pair of extension portions extended towards the first link so as to prevent interference with the first link by interposing the first link therebetween; and

a third link having one end connected to the second link, and rotated together with the second link, for moving the movable contactor to the closing position.
The toggle links of a switching mechanism for an air circuit breaker of claim 2, wherein the first link is one plate member, and the second link includes a pair of plate members disposed to be separated from each other with a predetermined distance.