Patent Publication Number: US-9899177-B2

Title: Delay time generation apparatus for air circuit breaker

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of earlier filing date and right of priority to Korean Patent Application No. 10-2015-0187794, filed on Dec. 28, 2015, the contents of which are all hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This specification relates to a delay time generation apparatus for an air circuit breaker, and more particularly, a delay time generation apparatus for an air circuit breaker capable of improving reliability for a generation of a delay time in the air circuit breaker. 
     2. Background of the Invention 
     In general, a circuit breaker refers to an apparatus that opens and closes a load in a power system, a distribution system or an electric circuit and cuts off a current when an accident such as grounding or short-circuit occurs. 
     Some of such circuit breakers are provided with a relay executing a so-called making current release (MCR) function of setting a current value, detecting an introduced current and instantaneously blocking an introduction of a heavy current over the set current value, so as to prevent the introduction of the heavy current into a load side. 
     In order for the relay to execute the MCR function, a case of opening the circuit breaker for blocking a fault current (i.e., separating a fixed contactor and a movable contactor from each other) in a closed state of the circuit breaker should be distinguished from a case of blocking a fault current upon closing the circuit breaker (i.e., contacting the movable contactor contact with the fixed contactor) on a circuit which is already open due to an occurrence of a fault. 
     To distinguish the two cases, a delay time generation apparatus for a circuit breaker is used for outputting a contact signal (or conductive signal) with a predetermine delay time after the movable contactor is brought into contact with the fixed contactor. 
     Meanwhile,  FIG. 1  is a schematic view illustrating a delay time generation apparatus for a circuit breaker according to the related art. 
     As illustrated in  FIG. 1 , the related art delay time generation apparatus includes a switch  20  disposed at one side of a main shaft  10  to output a signal upon detecting a contact state, a delay plate  30  rotatably disposed to be contactable with or separated from the switch  20 , and a lever  12  integrally formed with the main shaft  10  to press the delay plate  30  upon a rotation of the main shaft  10  in a breaking direction, such that the delay plate  30  is rotated away from the switch  20 . 
     The delay plate  30  includes a rotation shaft  31 , a first arm  33  extending from the rotation shaft  31  toward the main shaft  10  and contactable with the lever  12 , and a second arm  35  extending from the rotation shaft  31  toward the switch  20  and rotated simultaneously with the first arm  33  to be contactable with the switch  20 . 
     In this instance, the second arm  35  is connected with a spring  37  that supplies an elastic force in a direction that the second arm  35  comes in contact with the switch  20 . 
     Also, the second arm  35  is provided with a mass body  39  causing a predetermined delay time due to inertia upon a rotation of the main shaft  10  in a closing direction. 
     With the configuration, in a broke state of the circuit breaker, when the main shaft  10  is rotated in the closing direction, the delay plate  30  is rotated toward the switch  20  in a clockwise direction by the elastic force of the spring  37 . In this instance, a predetermined delay time is generated during the rotation of the delay plate  30  due to the inertia of the mass body  39 . The delay time is generated in response to the delay plate  30  being brought into contact with the switch  20  after the fixed contactor and the movable contactor are brought into contact with each other due to the rotation of the main shaft  10 . 
     However, the related art delay time generation apparatus uses a large mass body, the apparatus increases in size which makes it difficult to install the generation apparatus in a narrow space. 
     Also, the generation of the delay time using the mass body brings about lowered accuracy of the delay time and difficulty in ensuring a sufficient delay time. 
     SUMMARY OF THE INVENTION 
     Therefore, to obviate those problems and other drawbacks of the related art, an aspect of the detailed description is to provide a delay time generation apparatus for an air circuit breaker, capable of improving reliability for a generation of a delay time of the air circuit breaker. 
     To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a delay time generation apparatus for an air circuit breaker, for outputting a conductive signal through a switch with a preset delay time when a movable contactor is brought into contact with a fixed contactor, the apparatus including a pin portion moved downward when the movable contactor is brought into contact with the fixed contactor, a main shaft rotated in response to a movement of the movable contactor to a contact position or a trip position, a first rotating unit located to be closely adhered on the main shaft, the first rotating unit being released from the adhered state on the main shaft and rotated in a clockwise direction through the pin portion when the movable contactor is moved to the contact position, and rotated in a counterclockwise direction through the main shaft when the movable contactor is moved to the trip position, and a second rotating unit located below the first rotating unit, the second rotating unit being rotated in response to the rotation of the first rotating unit to be brought into contact with or separated from the switch such that the conductive signal is output. 
     Also, the apparatus may further include a spring member having one side connected to the second rotating unit, to apply an elastic force to the second rotating unit to be rotated in the clockwise direction such that the second rotating unit and the switch are separated from each other, when the movable contactor is located at the trip position. Here, a connected portion between the spring member and the second rotating unit may be changed in response to the rotation of the second rotating unit when the movable contactor is moved to the contact position, and thus the spring member applies the elastic force to the second rotating unit to be rotated in the counterclockwise direction such that the second rotating unit is brought into contact with the switch. 
     The first rotating unit may include a body portion having connection arms extending from both sides thereof in a bent manner to be connected to an inside of the air circuit breaker, a holder located between the connection arms and pushed down by the pin portion when the movable contactor is moved to the contact position, a rotation adjusting plate extending from a lower end of a side surface of the body portion toward the second rotating unit, wherein the rotating adjusting plate pushes the second rotating unit, in response to the rotation of the body portion, such that the second rotating unit is brought into contact with the switch, when the movable contactor is moved to the contact position, and wherein the rotation adjusting plate rotates the second rotating unit, in response to the rotation of the body portion, such that the second rotating unit is separated from the switch, when the movable contactor is moved to the trip position, and a stopping portion extending from a lower end of the body portion toward the main shaft, and brought into contact with the main shaft to rotate the body portion when the movable contactor is moved to the trip position. 
     The stopping portion may include an extending plate extending from the lower end of the body portion toward the main shaft, and an adhering plate extending downwardly from a front end of the extending plate in a bent manner, and brought into contact with the main shaft in response to the rotation of the main shaft. 
     The holder may be provided with protrusion protruding upwardly from an upper end thereof and preventing shaking of the pin portion upon being closely adhered on the pin portion. 
     The second rotating unit may include a first rotating plate located below the first rotating unit, and rotated by the rotation adjusting plate to be brought into contact with the switch when the movable contactor is moved to the contact position, and a second rotating plate extending from one side of the first rotating plate toward the first rotating unit, and rotated by the rotation adjusting plate such that the first rotating plate is separated from the switch when the movable contactor is moved to the trip position. 
     The main shaft may be provided with a protruding portion protruding toward the first rotating unit, the protruding portion pushing the stopping portion to rotate the first rotating unit, such that the second rotating unit is rotated in response to the rotation of the first rotating unit to be separated from the switch when the movable contactor is moved to the trip position. 
     The second rotating plate may be inwardly bent by a predetermined angle. 
     The first rotating plate may be provided with a connecting plate disposed on one side thereof and having an insertion hole in which one side of the spring member is inserted. 
     The first rotating plate may be provided with a hinge portion disposed on another side thereof and connected to an inside of the air circuit breaker. 
     The pin portion may be provided with a pressing plate disposed on a lower end thereof to press the first rotating unit in response to a movement of the pin portion. 
     A delay time generation apparatus for an air circuit breaker according to the present invention can provide an effect of ensuring a delay time as long as possible even in a narrow space upon outputting a signal related to a conductive state, by virtue of interaction of a main shaft, a pin portion, a first rotating unit, a second rotating unit and a spring member. 
     Also, a simplified structure of the apparatus may result in a reduction of a fabrication time, a simplification of fabricating processes and a reduction of fabricating costs. 
     The spring member may apply an elastic force in the same direction as a rotating direction of the second rotating unit. This may prevent the second rotating unit from being re-rotated in an opposite direction to the rotating direction due to a collision against another component of the air circuit breaker. 
     Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description. 
    
    
     
       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 exemplary embodiments and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a schematic view illustrating a delay time generation apparatus for a circuit breaker according to the related art; 
         FIG. 2  is a schematic view in a trip state of a delay time generation apparatus provided in an air circuit breaker in accordance with the present invention; 
         FIG. 3  is a schematic view in a contact state (current-flowing state) of the delay time generation apparatus provided in the air circuit breaker in accordance with the present invention; 
         FIG. 4A  is a schematic view illustrating a state that a current starts to flow in the air circuit breaker in accordance with the present invention; 
         FIG. 4B  is a schematic view illustrating a state just before a current flows in the air circuit breaker in accordance with the present invention; 
         FIG. 4C  is a schematic view illustrating a state that a current flows in the air circuit breaker in accordance with the present invention; 
         FIG. 5  is a perspective view illustrating a pin portion provided in the delay time generation apparatus for the air circuit breaker in accordance with the present invention; 
         FIG. 6  is a perspective view illustrating a first rotating unit provided in the delay time generation apparatus for the air circuit breaker in accordance with the present invention; and 
         FIG. 7  is a perspective view illustrating a second rotating unit provided in the delay time generation apparatus for the air circuit breaker in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Description will now be given of a delay time generation apparatus for an air circuit breaker in detail according to one embodiment disclosed herein, with reference to the accompanying drawings. 
       FIG. 2  is a schematic view in a trip state of a delay time generation apparatus provided in an air circuit breaker in accordance with the present invention,  FIG. 3  is a schematic view in a contact state (current-flowing state) of the delay time generation apparatus provided in the air circuit breaker in accordance with the present invention,  FIG. 4A  is a schematic view illustrating a state that a current starts to flow in the air circuit breaker in accordance with the present invention,  FIG. 4B  is a schematic view illustrating a state just before a current flows in the air circuit breaker in accordance with the present invention, and  FIG. 4C  is a schematic view illustrating a state that a current flows in the air circuit breaker in accordance with the present invention. 
     Also,  FIG. 5  is a perspective view illustrating a pin portion provided in the delay time generation apparatus for the air circuit breaker in accordance with the present invention,  FIG. 6  is a perspective view illustrating a first rotating unit provided in the delay time generation apparatus for the air circuit breaker in accordance with the present invention, and  FIG. 7  is a perspective view illustrating a second rotating unit provided in the delay time generation apparatus for the air circuit breaker in accordance with the present invention. 
     As illustrated in  FIGS. 2 and 3 , an air circuit breaker  100  according to the present invention is provided with a delay time generation apparatus that outputs a conductive signal (or contact signal) through a switch  190  with a predetermined delay time while a movable contactor  120  is brought into contact with a fixed contactor  110 . 
     In this instance, the delay time generation apparatus includes a pin portion  130 , a main shaft  160 , a first rotating unit  140  and a second rotating unit  150 . 
     The pin portion  130  is moved down in response to an operation of an actuator  180  to push down the first rotating unit  140  and rotate the first rotating unit  140  when the movable contactor  120  and the fixed contactor  110  are in a contact state. 
     In this instance, as illustrated in  FIG. 5 , the pin portion  130  is further provided with a pressing plate  131  on a lower end thereof. Thus, as the pin portion  130  is moved, the pressing plate  131  presses the first rotating unit  140  to be rotated. 
     The main shaft  160  is rotatably connected with the movable contactor  120  through a connection link  121 . When the movable contactor  120  is moved to a contact position (or conductive position) or a trip position, the main shaft  160  is rotated in a clockwise or counterclockwise direction, to be spaced apart from or closely adhered on the first rotating unit  140 . 
     The first rotating unit  140  is located adjacent to the main shaft  160 . When the movable contactor  120  is moved to the contact position, the close adhesion of the first rotating unit  140  on the main shaft  160  is released and the first rotating unit  140  is rotated in the clockwise direction through the pin portion  130 . On the other hand, when the movable contactor  120  is moved to the trip position, the first rotating unit  140  is rotated in the counterclockwise direction through the main shaft  160 . 
     The second rotating unit  150  is located below the first rotating unit  140 . The second rotating unit  150  is rotated, in response to the rotation of the first rotating unit  140 , to be brought into contact with or separated from the switch  190 . Accordingly, a conductive signal is output with a predetermined delay time. 
     In this instance, the delay time generation apparatus may further be provided with a spring member  170 . The spring member  170  has one side connected to the second rotating unit  150 . Accordingly, when the movable contactor  150  is moved to the trip position, the spring member  170  applies an elastic force to the second rotating unit  150  such that the second rotating unit  150  is rotated in the clockwise direction to be separated from the switch  190 . On the other hand, when the movable contactor  120  is moved to the contact position, a connected position between the spring member  170  and the second rotating unit  150  is changed in response to the rotation of the second rotating unit  150 . Accordingly, the spring member  170  applies the elastic force to the second rotating unit  150  to be rotated in the counterclockwise direction, such that the second rotating unit  150  is brought into contact with the switch  190 . 
     Meanwhile, as illustrated in  FIG. 6 , the first rotating unit  140  includes a body portion  141 , a holder  143 , a rotation adjusting plate  145  and a stopping portion  147 . 
     The body portion  141  is provided on both sides thereof with connection arms  141   a  each with a through hole  141   a - 1 . The connection arms  141   a  extend from the both sides of the body portion  141  in a bent manner to be connected to an inside of the air circuit breaker  100 . 
     The holder  143  is located between the connection arms  141   a . When the movable contactor  120  is moved to the contact position, the holder  143  receives a force downwardly applied through the pin portion  130 . 
     In this instance, a protrusion  143   a  protrudes upwardly from an upper end of the holder  143 , so as to prevent shaking of the pin portion  130  when being closely adhered on the pin portion  130 . 
     The rotation adjusting plate  145  extends from a lower end of a side surface of the body portion  141  toward the second rotating unit  150 . When the movable contactor  120  is moved to the trip position, the rotation adjusting plate  145  rotates the second rotating unit  150  in the clockwise direction, in response to the rotation of the body portion  141 , such that the second rotating unit  150  is separated from the switch  190 . On the other hand, when the movable contactor  120  is moved to the contact position, the rotation adjusting plate  145  rotates the second rotating unit  150  in the counterclockwise direction, in response to the rotation of the body portion  141 , such that the second rotating unit  150  is brought into contact with the switch  190 . 
     The stopping portion  147  extends from a lower end of the body portion  141  toward the main shaft  160 . When the movable contactor  120  is moved to the trip position, the stopping portion  147  is brought into contact with the main shaft  160 , such that the body portion  141  is rotated. 
     In this instance, the stopping portion  147  is provided with an extending plate  147   a  and an adhering plate  147   b.    
     The extending plate  147   a  extends from the lower end of the body portion  141  toward the main shaft  160 . 
     The adhering plate  147   b  extends downwardly from a front end of the extending plate  147   a  in a bent manner. Accordingly, the adhering plate  147   b  is brought into contact with the main shaft  160 , in response to the rotation of the main shaft  160 , thereby rotating the first rotating unit  140 . 
     Meanwhile, as illustrated in  FIG. 7 , the second rotating unit  150  includes a first rotating plate  151  and a second rotating plate  153 . 
     The first rotating plate  151  is located below the first rotating unit  140 . When the movable contactor  120  is moved to the contact position, the first rotating plate  151  is rotated by the rotation adjusting plate  145  to be brought into contact with the switch  190 . 
     The second rotating plate  153  extends from one side of the first rotating plate  151  toward the first rotating unit  140 . When the movable contactor  120  is moved to the trip position, the second rotating plate  153  is rotated by the rotation adjusting plate  145  such that the first rotating plate  151  is separated from the switch  190 . 
     In this instance, the second rotating plate  153  is curved inwardly. Accordingly, when the movable contactor  120  is moved to the contact position and thus the first rotating plate  151  is in the contact state with the switch  190 , the second rotating plate  153  is located above the rotation adjusting plate  145  in a covering manner. 
     Therefore, when the first rotating unit  140  is rotated in response to the movement of the movable contactor  120  to the trip position, the second rotation plate  153  is rotated by the rotation adjusting plate  145  such that the first rotating plate  151  is separated from the switch  190 . 
     In addition, a connecting plate  151   a  with an insertion hole  151   a - 1  in which one side of the spring member  170  is inserted is further provided on one side of the first rotating plate  151 , and a hinge portion  151   b  connected to the inside of the air circuit breaker  100  is further provided on another side of the first rotating plate  151 . 
     Therefore, the spring member  170  is connected to the connecting plate  151   a  through the insertion hole  151   a - 1  to supply an elastic force to the first rotating plate  151 , and the first rotating plate  151  is rotated by being connected into the air circuit breaker  100  through a coupling hole  151   b - 1  formed through the hinge portion  151   b.    
     Meanwhile, the main shaft  160  is provided with a protruding portion  161  protruding toward the first rotating unit  140 . When the movable contactor  120  is moved to the trip position, the protruding portion  161  pushes the stopping portion  147  to rotate the first rotating unit  140 , and the second rotating unit  150  is rotated in response to the rotation of the first rotating unit  140 , so as to be separated from the switch  190 . 
     Hereinafter, an operation of the delay time generation apparatus for the air circuit breaker according to the present invention will be described in detail with reference to the accompanying drawings. 
     First, as illustrated in  FIG. 4A , when the movable contactor  120  is located at the trip position, the first rotating unit  140  is in a contact state with an upper end of the protruding portion  161  of the main shaft  160 , and the pin portion  130  is located on an upper end of the first rotating unit  140 . 
     In this instance, as illustrated in  FIG. 4B , when the movable contactor  120  is moved to the contact position, the main shaft  160  which is connected with the movable contactor  120  through the connection link  121  is rotated in the clockwise direction, thereby releasing the contact state between the protruding portion  161  and the first rotating unit  140 . 
     Also, as illustrated in  FIG. 4C , when the movable contactor  120  is brought into contact with the fixed contactor  110 , the pin portion  130  is moved downward by an operation of the actuator  180  to push down the first rotating unit  140 . Accordingly, the first rotating unit  140  is rotated in the clockwise direction. 
     Also, when the first rotating unit  140  is rotated in the clockwise direction, the rotation adjusting plate  145  provided on the first rotating unit  140  pushes the first rotating plate  151  of the second rotating unit  150  located below the rotation adjusting plate  145 , such that the second rotating unit  150  is rotated in the counterclockwise direction. Accordingly, the first rotating plate  151  is brought into contact with the switch  190 . 
     In this instance, the spring member  170  located below the second rotating unit  150  and connected to the first rotating plate  151  applies an elastic force to the second rotating unit  150  in the clockwise direction when the movable contactor  120  is in a trip state. However, when the movable contactor  120  is moved to the contact position, a connected portion between the spring member  170  and the first rotating plate  151  is moved from a portion P 1  to portions P 2  and P 3  in a sequential manner, in response to the rotation of the second rotating unit  150 . Accordingly, when the first rotating plate  151  is finally brought into contact with the switch  190 , the spring member  170  applies the elastic force to the second rotating unit  150  to be rotated in the counterclockwise direction, thereby maintaining the contact state between the first rotating plate  151  and the switch  190 . 
     Also, a load of the spring member  170  may be adjusted in the range of 1.5 kgf to 2.5 kgf, to ensure a delay time as long as possible within a narrow space. 
     Through such processes, after a preset time is delayed in the contact state between the movable contactor  120  and the fixed contactor  110 , the conductive signal is output through the switch  190 . 
     Meanwhile, when the movable contactor  120  is moved from the contact position to the trip position, the main shaft  160  connected to the movable contactor  120  through the connection link  121  is rotated in the counterclockwise direction. Accordingly, the protruding portion  161  formed on the main shaft  160  pushes the stopping portion  147  provided on the first rotating unit  140  and thereby the first rotating unit  140  is rotated in the counterclockwise direction. 
     Also, the rotation adjusting plate  145  provided on the first rotating unit  140  is then brought into contact with the second rotating plate  153  provided on the second rotating unit  150  and thus the second rotating unit  150  is rotated in the clockwise direction, thereby separating the first rotating plate  151  from the switch  90 . 
     In this instance, while the first rotating plate  151  and the switch  190  are in the contact state, the contact state is maintained by virtue of the elastic force applied by the spring member  170  to rotate the first rotating plate  151  in the counterclockwise direction. On the other hand, when the first rotating plate  151  is separated from the switch  190  in response to the movement of the movable contactor  120  to the trip position, the connected portion between the first rotating plate  151  and the spring member  170  is moved from the portion P 3  to the portion P 1 . Accordingly, the separate state between the first rotating plate  151  and the switch  190  is maintained by the elastic force finally applied by the spring member  170  to rotate the first rotating plate  151  in the clockwise direction. 
     The delay time generation apparatus for the air circuit breaker according to the present invention having the configuration can ensure a delay time as long as possible even within a narrow space upon outputting a signal related to a conductive state, by virtue of interaction of the main shaft  160 , the pin portion  130 , the first rotating unit  140 , the second rotating unit  150  and the spring member  170 . 
     Also, a simplified structure of the apparatus may result in a reduction of a fabrication time, a simplification of fabricating processes and a reduction of fabricating costs. 
     The spring member  170  may apply the elastic force in the same direction as the rotating direction of the second rotating unit  150 . This may prevent the second rotating unit  150  from being re-rotated in an opposite direction to the rotating direction due to a collision against another component of the air circuit breaker. 
     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.