Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2017-0046209, filed on Apr. 10, 2017, the disclosure of which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a movable contact assembly for a circuit breaker, and more particularly, to a movable contact assembly for a circuit breaker in which a pressurizing protrusion for pushing a catch is provided at each of movable contact fingers and thus, when current limiting interruption occurs in any one of the movable contact fingers, reinputting of the movable contact fingers is prevented such that blocking thereof is stably kept.
2. Discussion of Related Art
Generally, circuit breakers are electrical devices which are installed at a power transmission site, a power substation, or an electrical circuit to cut off a circuit when a load is opened or closed, the ground is performed, or an accident such as a short circuit or the like occurs. An air circuit breaker among such circuit breakers is a circuit breaker which uses air as an extinguishing medium and is mainly employed for a low voltage device, and a movable contact assembly of a circuit breaker according to the present invention may be applied to the air circuit breaker and the like.
Interruption types of circuit breakers includes delay trip (demonstration trip) interruption for preventing overheating when an overcurrent flows (e.g., 1 to 1.5 times a rated current), and instantaneous trip interruption when a fault current (e.g., several to 10 times the rated current) occurs. The instantaneous trip interruption includes interruption caused by the mechanical action of an over current relay or a switching mechanism (instantaneous interruption in a general sense), and current limiting interruption caused by an electromagnetic repulsive force between a fixed contact and a movable contact.
The current limiting interruption is performed to immediately separate the movable contact from the fixed contact using the electromagnetic repulsive force generated between the movable contact and the fixed contact when a large current such as a short-circuit current flows, thereby cutting off a circuit to protect the circuit and a load, and a circuit breaker employing the current limiting interruption may be referred to as a current limiting circuit breaker.
Here, the catch 160 is provided to prevent a phenomenon (rebound phenomenon) in which the movable contact 110 returns by colliding with a case or base mold (not shown) after being separated from a stator due to current limiting interruption. That is, the catch 160 prevents a reinputting of the movable contact 110 into the stator 210 during the current limiting interruption. When interruption by the mechanical action of the switching mechanism is performed, the movable contact holder 125 is moved together with the movable contact 110 such that a phenomenon in which the movable contact 110 rebounds independently may not occur, but when current limiting interruption is performed, the movable contact 110 is separated from the movable contact holder 125 and is moved independently such that there is a probability in which the movable contact 110 is input again due to a rebound phenomenon and thus the catch 160 is provided to prevent the reinputting of the movable contact 110.
In the related art, however, the action of the catch 160 becomes operable only when all movable contacts 110 (two movable contacts in
Two movable contacts 110 will be distinguished and referred to as a first movable contact 111 and a second movable contact 112. Catch recesses 111a and 112a are respectively formed at lower portions of the first movable contact 111 and the second movable contact 112.
When both the first movable contact 111 and the second movable contact 112 are separated from the stator 210 due to current limiting interruption, the catch recesses 111a and 112a are moved upward to a position at which a protruding contact part is formed on an upper surface of the catch 160 (to a position of the first movable contact 111 in
As shown in
The present invention is directed to a movable contact assembly for a circuit breaker in which, when current limiting interruption occurs, a catch operates to prevent a reinputting of any one of movable contacts.
According to an aspect of the present invention, there is provided a movable contact assembly for a circuit breaker, which includes a fixed contact, a connector formed to protrude from one side of a terminal connected to a load or a power source, a plurality of movable contacts pivotably installed at the connector through a connector pin and configured to be contactable to or separable from the fixed contact, a side holder pivotably installed at the connector through the connector pin, a catch pivotably installed at the connector, supported on the side holder, and configured to restrict a rebound phenomenon of the plurality of movable contacts when current limiting interruption occurs, and a pressurizing protrusion formed at a lower portion of each of the plurality of movable contacts and configured to push the catch when the current limiting interruption occurs.
A latch may be pivotably installed at an intermediate portion of the side holder, a latch support to which the latch is contactable may be formed to protrude from one side of the lower portion of each of the plurality of movable contacts, and the pressurizing protrusion may be formed at a lower portion of the latch support.
The pressurizing protrusion may be formed in a triangular shape.
In an opened state, a lower surface of the pressurizing protrusion may be formed in a horizontal surface and an oblique surface thereof may be formed in an inclined surface.
An angle of the oblique surface may be formed in a range of 30 to 60 degrees relative to the lower surface.
The catch may include a base plate formed to have a length across the connector, a side plate formed to be bent on both sides of the base plate, a hook portion protruding from an upper portion of the base plate, and a hook protrusion protruding from an upper end of the side plate.
A circumferential protrusion and a circumferential recess may be formed along a circumferential surface at a lower end of the side holder.
An angle between the hook protrusion and an upper end of the circumferential protrusion based on the connector pin may be greater than an angle between the hook portion and the pressurizing protrusion based on the connector pin. In an input state, the hook portion may be positioned inside a pivotal circumferential surface of the pressurizing protrusion.
The above and other objects, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which:
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, the description is intended to fully illustrate the present invention so as to those skilled in the art to easily implement the present invention and it does not mean that the technical idea and scope of the present invention are limited.
A movable contact assembly 20 of a circuit breaker according to one embodiment of the present invention includes a fixed contact 10, a connector 35 formed to protrude from one side of a terminal 30 connected to a load or a power source, a plurality of movable contacts 40 pivotably installed at the connector 35 through a connector pin 39 and configured to be contactable to or detachable from the fixed contact 10, a side holder 50 pivotably installed at the connector 35 through the connector pin 39, a catch 80 pivotably installed at the connector 35, supported on the side holder 50, and configured to restrict a rebound phenomenon of the plurality of movable contacts 40 when current limiting interruption is performed, and a pressurizing protrusion 45 formed at a lower portion of each of the plurality of movable contacts 40 and configured to push the catch 80 when current limiting interruption is performed.
The fixed contact 10 may be in the form of a roughly “U” shape (see
The movable contact assembly 20 may include the terminal 30, the connector 35, the plurality of movable contacts 40, the side holder 50, an upper holder 55, a spring holder 65, a latch 70, and the catch 80.
The terminal 30 is formed of a conductive material and is fixedly coupled to a terminal of a power source or load (not shown).
The connector 35 protrudes from one side of the terminal 30 and has a fork-shaped connecting part 36 such that the plurality of movable contacts 40 may be coupled to the connector 35. The connector 35 may integrally be formed with the terminal 30.
Each of the plurality of movable contacts 40 (also referred to as a movable contact finger) is pivotably coupled to the connecting part 36 of the connector 35 through the connector pin 39. Here, the plurality of movable contacts 40 are provided. In the present embodiment, an example configured with two movable contacts is shown. In this case, each of the two movable contacts is distinguished and referred to as a first movable contact 40a and a second movable contact 40b. When movable contacts are required to be distinguished from each other, suffix delimiters “a” and “b” will be added thereto. When the matters which are generally applied to movable contacts are described, the movable contacts are collectively referred without adding separate delimiters thereto.
A movable contact tip 41 is provided at one side of an upper portion of each of the plurality of movable contacts 40. A guide coupling hole 42 to which a movable contact guide 60 may be coupled is formed at the upper portion of each of the plurality of movable contacts 40. A pin hole 43 to which the connector pin 39 may be coupled is formed at a lower portion of each of the plurality of movable contacts 40. A latch support 44 with which a roller 75 of the latch 70 may be in contact is formed to protrude from one side of the lower portion of each of the plurality of movable contacts 40. The pressurizing protrusion 45 may be formed to protrude from a lower portion of the latch support 44 to come into contact with the catch 80.
The pressurizing protrusion 45 may be formed in a triangular shape. In an opened state, a lower surface of the pressurizing protrusion 45 may be formed in a horizontal surface and an oblique surface thereof may be formed in an inclined surface. Here, an angle of the oblique surface may be formed within the range of 30 degrees to 60 degrees relative to the lower surface. Consequently, the pressurizing protrusion 45 has a mechanical shape capable of easily pushing the catch 80, concentrating a force on a corner portion, preventing a malfunction.
A pair of side holders 50 are provided and coupled to both sides of the connecting part 36. A lower portion of each of the pair of side holders 50 is pivotably coupled to the connecting part 36 through the connector pin 39. Uneven parts 51 and 52 are formed along a circumferential surface of a lower end of each of the pair of side holders 50 (see
The upper holder 55 is coupled to an upper portion of each of the pair of side holders 50. Each of the pair of side holders 50 supports and guides each of the plurality of movable contacts 40 and the movable contact guide 60.
A link 58 and a link pin 59 are installed at each of the pair of upper holders 55 to input or open each of the plurality of movable contacts 40 by a force transmitted from the switching mechanism (not shown). A pair of links 58 are provided and installed both sides of each of the pair of upper holders 55, and the link pin 59 is installed to pass through the pair of links 58 and the pair of upper holders 55. A switching drive force transmitted from the switching mechanism pushes or pulls the pair of upper holders 55 via the pair of links 58 and the link pin 59 to move the plurality of movable contacts 40 of the movable contact assembly 20.
The movable contact guide 60 is coupled to engaged with each of movable contacts 40a and 40b to support the movable contacts 40a and 40b, and simultaneously, guide a movement of each of the movable contacts 40a and 40b. The movable contact guide 60 slidably moves along the upper surface of each of the pair of upper holders 55 to guide the movable contact 40.
The spring holder 65 is fixed to one side of each of the pair of side holders 50 and supports an upper end of a spring 68.
The latch 70 is pivotably installed at an intermediate portion of each of the pair of side holders 50 and supports a lower end of the spring 68. The roller 75 may be provided at the latch 70. When the roller 75 receives a force by a movement of the movable contact 40 to move the latch 70 upward, the spring 68 is pressurized to further promote the movement of the movable contact 40. Consequently, an opening speed of the movable contact 40 increases.
The catch 80 is pivotably installed at the connector 35 through a catch pin 89. The catch 80 includes a base plate 81 formed to have a length across the connecting part 36 of the connector 35, a side plate 82 formed to be bent at both sides of the base plate 81, a hook part 83 protruding from an upper portion of the base plate 81, and a hook protrusion 84 protruding from an upper end of the side plate 82.
The catch 80 may be pivoted around the catch pin 89. A torsion spring 88 is installed at the catch pin 89 of the catch 80 to act a force for pivoting the catch 80 in a counterclockwise (an opening direction).
The catch 80 may be supported such that the hook protrusion 84 comes into contact with the uneven parts 51 and 52 of lower circumferential surfaces of the pair of side holders 50.
A switching operation performed by the switching mechanism will be described with reference to
As shown in
As shown in
During opening, as the side holder 50 is pivoted in the counterclockwise direction, the circumferential protrusion 51 pushes the catch 80 and thus the catch 80 is pivoted in the clockwise direction. At this point, the hook part 83 of the catch 80 is in a state of having been moved to the outside (a rear side) and, the catch 80 does not interfere with the movement of the movable contact 40 when the catch 80 is input. The aforementioned will be described in detail with reference to
When a current limiting is performed, since interruption is performed not by the switching mechanism, the link 58, the link pin 59, the upper holder 55 and the side holder 50 are maintained at their positions when inputting.
The first movable contact 40a is in an opened state by an electromagnetic repulsive force with the fixed contact 10. The second movable contact 40b is maintained in a state of being in contact with the fixed contact 10.
The pressurizing protrusion 45a of the first movable contact 40a is in a state of escaping from the hook part 83 of the catch 80, and the pressurizing protrusion 45b of the second movable contact 40b is in a state of being in contact with the inner surface of the base plate 81 of the catch 80.
A procedure in which current limiting interruption occurs in only one movable contact 40 will be described in detail with reference to
A description will be made with reference to
A description will be made with reference to
Consequently, the catch 80 may prevent reinputting even when only one movable contact 40 is opened.
A relationship between the pressurizing protrusion 45 and the catch 80 will be described in more detail with reference to
In the input state, the hook part 83 of the catch 80 is in a state of being positioned (inputted) into an inner side of a pivotal circumferential surface R of an edge of the pressurizing protrusion 45. Therefore, when the pressurizing protrusion 45 returns by the rebound phenomenon after the pressurizing protrusion 45 pushes out the catch 80 due to the current limiting interruption, a lower surface 46 of the pressurizing protrusion 45 is hooked on the upper surface of the hook part 83 of the catch 80.
Among the embodiments according to the present invention, the action of the catch 80 is not separately described for all the movable contacts 40 when the current limiting interruption occurs, but when the rebound phenomenon occurs, reinputting of all the movable contacts 40 is further prevented.
In accordance with a movable contact assembly for a circuit breaker according to one embodiment of the present invention, when current limiting interruption occurs in any one of a plurality of movable contacts, a catch operation is performed to prevent reinputting. A pressurizing protrusion provided at a lower portion of each of the plurality of movable contacts pushes the catch when the current limiting interruption occurs and the catch returns by a torsion spring, such that reinputting is prevented even when a rebound phenomenon occurs in any one of the plurality of movable contacts.
Although the embodiments have been described with reference to illustrative embodiments of the present invention, it should be understood that numerous alternations and modifications can be devised by those skilled in the art to which the present invention pertains without departing from the essential features of the present invention. The embodiments disclosed herein, therefore, are not to be taken in a sense for limiting the technical concept of the present disclosure but for explanation thereof, and the range of the technical concept of the present invention is not limited to these embodiments. That is, the scope of the present invention should be construed by the appended claims, along with the full range of equivalents to which such claims are entitled.
Number | Date | Country | Kind |
---|---|---|---|
10-2017-0046209 | Apr 2017 | KR | national |
Number | Name | Date | Kind |
---|---|---|---|
4484164 | McClellan | Nov 1984 | A |
5793270 | Beck | Aug 1998 | A |
5874699 | Beck | Feb 1999 | A |
6337449 | Brouillat et al. | Jan 2002 | B1 |
6563407 | Kramer | May 2003 | B2 |
9299518 | Biedunkiewicz | Mar 2016 | B2 |
9330859 | Biedunkiewicz | May 2016 | B2 |
20090065341 | Shmukler | Mar 2009 | A1 |
20170323751 | Sohn | Nov 2017 | A1 |
20180294122 | Seo | Oct 2018 | A1 |
Number | Date | Country |
---|---|---|
102129942 | Jul 2011 | CN |
202058671 | Nov 2011 | CN |
106252169 | Dec 2016 | CN |
101019030 | Mar 2011 | KR |
20110085497 | Jul 2011 | KR |
101079012 | Nov 2011 | KR |
101141537 | May 2012 | KR |
Entry |
---|
European Search Report for related European Application No. 18165469.0; report dated Sep. 6, 2018; (10 pages). |
Chinese Office Action for related Chinese Application No. 201810315103.5; action dated Mar. 22, 2019; (8 pages). |
Number | Date | Country | |
---|---|---|---|
20180294122 A1 | Oct 2018 | US |