Patent Publication Number: US-2022239074-A1

Title: Interlock structure of bypass transfer switching device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2021-0012495, filed Jan. 28, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates generally to an interlock structure of a bypass transfer switching device and, more particularly, to an interlock structure of a bypass transfer switching device, the interlock structure being capable of physically preventing manual switching of an automatic transfer switch when supply power is bypassed and capable of automatically opening a lever input portion of the automatic transfer switch drawn from a switchboard. 
     Description of the Related Art 
     In general, a large building or a factory receives a normal supply from a source of a power supply such as Korea Electric Power Corporation. When an abnormality like a power outage occurs in the normal supply, the above facilities generate an alternative supply using a power generator provided inside. In a large building or the factory, an automatic transfer switching device including an automatic transfer switch (ATS) is provided to supply electric power to a load side by connecting the normal supply to the load side in normal times and to supply emergency electric power to the load side by connecting the alternative supply to the load side when an abnormality occurs in a source of the normal supply. The automatic transfer switching device consists of automatic transfer switches connected to each other in parallel. When an error occurs in one of the automatic transfer switches, the automatic transfer switching device performs switching to supply a power supply through another automatic transfer switch arranged in parallel. Accordingly, the automatic transfer switching device is provided as a bypass transfer switching device so that maintenance, testing, etc. of an automatic transfer switch with an error may be efficiently performed. 
     As shown in  FIG. 1 , the bypass transfer switching device has an automatic transfer switch  10  and a bypass switch  20  in a switchboard  30 . As shown in  FIG. 2 , at an fixed terminal portion of each switch  10 ,  20 , a normal supply terminal  10 - 1 ,  20 - 1  provided to supply the normal supply and an alternative supply terminal  10 - 2 ,  20 - 2  provided to supply the alternative supply, and a load terminal  10 - 3 ,  20 - 3  provided to supply a power supply to the load supply are wired in parallel connection, so that a moving terminal  10 - 4 ,  20 - 4  provided at the switch  10 ,  20  performs switching of the power supply terminal  10 - 1 ,  10 - 2 ,  20 - 1 , and  20 - 2 . As shown in  FIG. 1 , a lever input portion  10   a  is provided at a front surface of the automatic transfer switch  10  and administrator inputs a lever to the lever input portion  10   a , thereby manually switching a power supply of the automatic transfer switch  10 . Meanwhile, when maintenance, repair, or testing of the automatic transfer switch  10  is required, the bypass transfer switching device performs switching so that a power supply is supplied without a cut-off to the load side through the bypass switch  20 . Therefore, maintenance, repair, or testing of the automatic transfer switch  10  may be efficiently performed. 
     However, the conventional bypass transfer switching device described above has following problems. 
     First, when the administrator switches the bypass switch  20  into the normal supply or the alternative supply in order to perform maintenance, repair, testing, etc. of the automatic transfer switch, without recognizing that the bypass switch  20  is switched, the administrator or an operator may input the lever into the lever input portion  10   a  to manually switch a power supply of the automatic transfer switch  10 , so there is a problem causing a fire accident in addition to a damage of an apparatus such as a power supply apparatus, etc. The bypass transfer switching device does not have a problem when an input power supply of the bypass switch  20  and an input power supply of the automatic transfer switch match with each other. However, when the operator performs manual switching of the automatic transfer switch through the lever input portion  10   a  from carelessness in the state in which the input power supply of the bypass switch  20  and the input power supply of the automatic transfer switch do not match with each other, there may be a problem causing a large accident. 
     Second, in a process that the administrator draws the automatic transfer switch  10  from the switchboard in a state in which a power supply is bypassed using the bypass switch  20  and performs testing or maintenance of the automatic transfer switch  10  and then returns the automatic transfer switch  10  to the switchboard, when an input power supply of the bypass switch  20  and an input power supply of the automatic transfer switch  10  do not match with each other, the bypass transfer switching device may have a problem of causing the above-described accidents. The administrator performs testing or maintenance while drawing the automatic transfer switch  10  from the switchboard  30  and then inputting the normal supply or the alternative supply to the automatic transfer switch  10 . When the operator returns the automatic transfer switch  10  into the switchboard  30  after completion of a series of operations, mismatch between the input power supply of the automatic transfer switch  10  and the input power supply of the bypass switch  20  may lead to an accident such as a damage of an apparatus and a fire accident. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and the present disclosure is intended to provide an interlock structure of a bypass transfer switching device, wherein when supply power is bypassed through a bypass switch, a lever input portion of an automatic transfer switch is automatically closed to fundamentally prevent manual switching of the automatic transfer switch. 
     In order to achieve the above object, according to one aspect of the present disclosure, there is provided an interlock structure of a bypass transfer switching device. The interlock structure of the bypass transfer switching device includes: an automatic transfer switch having a lever input portion of a through hole shape for manual switching of a normal supply and an alternative supply; a bypass switch configured to bypass electric power of the normal supply or the alternative supply supplied to a load side through the automatic transfer switch, the bypass switch including a bypass lever capable of manually switching a bypass circuit; and an interlock device configured to automatically close the lever input portion when the bypass lever is operated, wherein the interlock device may include: a main link coupled to the bypass lever, and configured to be lowered to a lower portion of a shaft of the bypass lever regardless of a turning direction of the bypass lever when the bypass lever is turned; an elevation member provided to be operated in conjunction with a raising and lowering operation of the main link; an elastic link configured to have elasticity allowing the elastic link to rotate toward the elevation member, and shaft-coupled to a lower portion of the elevation member in a close contact state with the lower portion of the elevation member; and an opening and closing plate shaft-coupled to the elastic link, and configured to open and close the lever input portion while being raised and lowered toward the lever input portion by a turning operation of the elastic link. 
     The automatic transfer switch may have a fixed bracket, a first end of the elastic link may be shaft-coupled to the fixed bracket through an elastic member, a second end of the elastic link may be shaft-coupled to the opening and closing plate, and at a portion between the first end and the second end of the elastic link, a contact bar being in close contact with the elevation member may be formed by protruding from the elastic link toward a first side of the elastic link. 
     A lower surface of the elevation member may include a straight line portion pressing the contact bar while being in contact with the contact bar and an inclined portion inclined upward from an end of the straight line portion toward the front of the automatic transfer switch. 
     The main link may include: a first link having a first end shaft-coupled to the lower portion of the bypass lever, and configured to be turned on the first end thereof in a direction opposite to a rotating direction of the bypass lever; and a second link shaft-coupled to a portion located between a second end of the first link and the elevation member, and configured to be turned downward on the second end of the first link by turning of the first link. 
     An interlock structure of a bypass transfer switching device according to the present disclosure is configured to automatically close a lever input portion of an automatic transfer switch when supply power is bypassed through a bypass switch. Therefore, it is possible to fundamentally prevent an operator from manually switching power supplies of the automatic transfer switch. Accordingly, the present disclosure has an effect that a damage to an apparatus at a load side or a fire accident due to mismatch between an input power supply of the bypass switch and a input power supply of the automatic transfer switch does not occur during repair and testing of the automatic transfer switch. 
     Furthermore, the interlock structure of the present disclosure is configured such that, when supply power is bypassed through the bypass switch, the automatic transfer switch may be input into a switchboard only when a power input direction of the automatic transfer switch drawn from the switchboard and a power input direction of the bypass switch match with each other. Accordingly, damage to an apparatus and an accident due to mismatch between the input power of the bypass switch and the input power of the automatic transfer switch can be prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a view showing a bypass transfer switching device. 
         FIG. 2  is a view showing a circuit structure of the bypass transfer switching device. 
         FIG. 3  is a view taken from a first side, the view showing a main portion of an interlock structure of the bypass transfer switching device according to an exemplary embodiment of the present disclosure. 
         FIG. 4  is a view taken from a second side, the view showing the main portion of the interlock structure of the bypass transfer switching device according to the exemplary embodiment of the present disclosure. 
         FIG. 5  is an exploded view taken from the second side, the view showing the interlock structure of the bypass transfer switching device according to the exemplary embodiment of the present disclosure. 
         FIGS. 6A and 6B  are a side view and a front view showing the interlock structure of the bypass transfer switching device with an automatic transfer switch in an operated state according to the exemplary embodiment of the present disclosure. 
         FIG. 7  is a side view showing the interlock structure of the bypass transfer switching device according to the exemplary embodiment of the present disclosure in a state in which power is bypassed to a normal supply through a bypass switch. 
         FIG. 8  is a side view showing the interlock structure of the bypass transfer switching device according to the exemplary embodiment of the present disclosure in a state in which power is bypassed to an alternative supply through the bypass switch. 
         FIG. 9  is a view showing a state in which the automatic transfer switch is drawn from the switchboard while power is bypassed to the alternative supply through the bypass switch. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It should be noted that the terms and words used in the specification and the claims should not be construed as being limited to ordinary meanings or dictionary definitions. Meanwhile, the embodiments described in the specification and the configurations illustrated in the drawings are merely examples and do not exhaustively present the technical spirit of the present disclosure. 
     Hereinbelow, an interlock structure of the bypass transfer switching device (hereinbelow, the interlock structure of the bypass transfer switching device refers to ‘the interlock structure’) according to an exemplary embodiment of the present disclosure will be described with reference to  FIGS. 3 to 9 . 
     With the bypass transfer switching device in which an automatic transfer switch  10  and a bypass switch  20  are connected to each other in parallel, the interlock structure includes an interlock device capable of closing a lever input portion  10   a  formed in the automatic transfer switch  10 , as shown in  FIG. 3 . The bypass switch  20  includes a bypass lever  21  capable of switching an input direction of the bypass switch  20 , the bypass lever  21 is provided to be turned upward and downward in a switchboard  30 , as shown in  FIGS. 6A, 7, and 8 . For example, when the bypass lever  21  is turned upward in the switchboard  30 , a normal supply is bypassed to the bypass switch  20 , and when the bypass lever  21  is turned downward in the switchboard  30 , an alternative supply is bypassed to the bypass switch. The bypass lever  21  includes an interlock bar  22  protruding downward from a rotary shaft in a direction perpendicular to the rotary shaft. The interlock bar is provided for a coupling with a main link, which will be described later. 
     As shown in  FIGS. 3 to 5 , the interlock device includes the main link  100 , an elevation member  200 , an elastic link  300 , and the opening and closing plate  400 . 
     The main link  100  transmits a turning operation of the bypass lever  21  to the opening and closing plate  400 . The main link  100  is provided between the bypass lever  21  and the elevation member  200 , as shown in  FIG. 4 . The main link  100  is shaft-coupled to the interlock bar  22  of the bypass lever  21 , and may be moved downward to a lower side of the bypass lever  21  regardless of a turning or counter-turning direction of the bypass lever  21 . Preferably, the main link  100  includes two links coupled to each other, and the two links refer to a first link  110  and a second link  120  for convenience of description. A first end of the first link  110  is shaft-coupled to the interlock bar  22  of the bypass lever  21  and the first link  110  is counter-turned on the first end thereof to the turning direction of the bypass lever  21 . For example, the first link  110  is configured such that, when the bypass lever  21  is turned counterclockwise, the first link  110  is turned clockwise as shown in  FIG. 7 , and when the bypass lever  21  is turned clockwise, the first link  110  is turned as shown in  FIG. 8 . The second link  120  is shaft-coupled to a second end of the first link  110  and is turned downward on the second end of the first link  110  to a lower side of the switchboard  30 . The second link  120  is shaft-coupled to a location between the second end of the first link  110  and the elevation member  200 . Regardless of the turning direction of the bypass lever  21 , when the bypass lever  21  is turned, the second link  120  is turned on the second end of the first link  110  to the lower side of the switchboard  30 . 
     The elevation member  200  is operated in conjunction with the main link  100  and serves to turn downward the elastic link  300 , which will be described later. As shown in  FIG. 4 , the elevation member  200  is coupled to the second link  120  so as to be operated in conjunction with the second link  120 . Preferably, the elevation member  200  has a guide plate  210  so that a raising and lowering operation of the elevation member  200  is efficiently performed without path deviation. The guide plate  210  is provided inside the switchboard  30  and has guide protrusions  211  provided to guide an elevation path of the elevation member  200 . The elevation member  200  has a longitudinal guide hole  220  corresponding to the guide protrusions  211 , whereby the elevation member  200  is raised and lowered on the guide plate  210  and is raised and lowered along the guide protrusions  211 . Meanwhile, a lower surface of the elevation member  200  is divided into a straight line portion  230  and an inclined portion  240 . The straight line portion  230  is a portion pressing the elastic link  300 , which will be described later, during the raising and lowering operation of the elevation member  200 . The straight line portion  230  has a shape that is a straight line with respect to the ground. The inclined portion  240  is configured to raise the opening and closing plate  400  while guiding naturally a turning operation of the elastic link  300  when the automatic transfer switch  10  is drawn from the switchboard  30 . A detailed description of the operation of the inclined portion  240  will be described later. As shown in  FIGS. 4 and 5 , the inclined portion  240  is formed to be inclined upward from the straight line portion  230  toward the front of the switchboard  30 . 
     The elastic link  300  is configured to directly raise the opening and closing plate  400  and may be turned by the raising and lowering operation of the elevation member  200 . The elastic link  300  is provided at the automatic transfer switch  10 . Specifically, a fixed bracket  11  is provided on the automatic transfer switch  10  as shown in  FIG. 7 , and the elastic link  300  may be turned on the fixed bracket  11 . A first end of the elastic link  300  is shaft-coupled to the fixed bracket  11  and a second end thereof is shaft-coupled to an upper end of the opening and closing plate  400 . With the above-described configuration, the second end of the elastic link  300  is turned on the first end thereof at the fixed bracket  11 , thereby raising and lowering the opening and closing plate  400  provided on the second end of the elastic link  300 . A contact bar  310  is provided between the first end and the second end of the elastic link  300 . The contact bar  310  is in close contact with the lower surface of the elevation member  200  and is a configuration in which the elastic link  300  is actually pressed when the elevation member  200  is lowered. The contact bar  310  protrudes from the elastic link  300  toward a first side of the elastic link  300 . Meanwhile, an elastic member  320  is provided on the first end of the elastic link  300 . The elastic member  320  supplies an elastic force to turning of the elastic link  300 . The elastic force of the elastic member  320  causes a force of the elastic link  300  to be turned toward the elevation member  200 . In other words, the elastic link  300  supplies the elastic force toward the elevation member  200  through the elastic member  320 . With the configuration of the elastic member  320 , in the present disclosure, the opening and closing plate  400  may operate efficiently and flexibly an operation of closing and opening a lever input portion  10   a . Preferably, the elastic member  320  is a torsion spring. 
     The opening and closing plate  400  serves to open and close the lever input portion  10   a  of the automatic transfer switch  10 . The opening and closing plate  400  is shaft-coupled to the second end of the elastic link  300  as shown in  FIG. 6A . The opening and closing plate  400  is raised and lowered toward the lever input portion  10   a  and to be operated in conjunction with a turning operation of the elastic link  300 . Preferably, the opening and closing plate  400  consists of a connecting portion  410  coupled to the elastic link  300  and a covering portion  420  covering the lever input portion  10   a . The connecting portion  410  has a longitudinal hole  411  formed in a longitudinal direction of the connecting portion  410 , and the fixed bracket  11  has guide protrusions  11   a  that may be located in the longitudinal hole  411 . 
     Hereinbelow, the operation of the interlock structure having the above-described structure will be described. 
       FIGS. 6A and 6B  are a side view and a front view showing an operating state the automatic transfer switch  10  in a state in which power is normally supplied. As shown in the drawings, the bypass lever  21  is in a state in which the bypass lever  21  is not connected to any power supply of the bypass switch  20 . The lever input portion  10   a  is in an open state so that manual switching of the automatic transfer switch  10  may be performed. When the automatic transfer switch  10  in the above-described open state of the lever input portion  10   a  needs maintenance, testing, etc., an operator bypasses a power supply, which is supplied through the automatic transfer switch  10 , through the bypass switch  20 . 
     For example, as shown in  FIG. 7 , the operator turns the bypass lever  21  upward to bypass the normal supply from the automatic transfer switch  10  to the bypass switch  20 . The bypass lever  21  is turned counterclockwise on a shaft and the first link  110  is turned clockwise on the interlock bar  22 . The second link  120  is turned on the second end of the first link  110  and the second link  120  in a horizontal state is turned downward, whereby the elevation member  200  is lowered along the guide plate  210 . 
     When the elevation member  200  is lowered, the contact bar  310  that is in closed contact with the straight line portion of the elevation member  200  is lowered while being pressed by the elevation member  200 . Eventually, the elastic link  300  is turned on the fixed bracket  11  to lower the second end thereof as shown in  FIGS. 6A and 7 . The elastic link  300  is in a state in which the elastic link  300  is pressed by the elevation member  200  and is returned to an initial location thereof by an elastic force of the torsion spring  320 . As described above, the second end of the elastic link  300  is lowered by the turning operation of the elastic link  300 , whereby the opening and closing plate  400  connected to the second end of the elastic link  300  is lowered to close the lever input portion  10   a.    
     Meanwhile,  FIG. 8  is a view showing a state in which the bypass lever  21  is turned to bypass the supply power to the alternative supply, and the view showing a state in which an operator turns the bypass lever  21  clockwise. The first link  110  is turned counterclockwise on the interlock bar  22  as shown in  FIGS. 6A and 8 , and turns the second link  120  clockwise. Therefore, the second link  120  is in a straight line with the first link  110  and the second end of the second link  120  is lowered to lower the elevation member  200 . 
     When the elevation member  200  is lowered, the contact bar  310  that is in close contact with the straight line portion  230  of the elevation member  200  is lowered while being pressed by the elevation member  200  as shown in  FIG. 7 . Therefore, the elastic link  300  is turned on the fixed bracket  11  and lowers the second end thereof as shown in  FIGS. 6A and 8 . The elastic link  300  is in a state in which the elastic link  300  is pressed by the elevation member  200  and is returned to the initial location thereof by an elastic force of the torsion spring  320 . As described above, the second end of the elastic link  300  is lowered by the turning operation of the elastic link  300 , whereby the opening and closing plate  400  connected to the second end of the elastic link  300  is lowered to close the lever input portion  10   a.    
     As described above, according to the present disclosure, when the bypass lever  21  is turned to bypass the supply power, the opening and closing plate  400  is automatically lowered to close the lever input portion  10   a . Therefore, in the state that the supply power is bypassed, it is impossible for the operator to manually switch the automatic transfer switch  10  through the lever input portion  10   a  regardless of an input power location of the bypass lever  21 . 
     Meanwhile,  FIG. 9  is a view showing a state in which the operator bypasses the supply power and then draws the automatic transfer switch  10  from the switchboard  30  for testing the automatic transfer switch  10 . According to the present disclosure, when the operator removes the automatic transfer switch  10  from the switchboard  30 , the opening and closing plate  400  is automatically raised to open the lever input portion  10   a . According to the present disclosure, when the automatic transfer switch  10  is drawn from the switchboard  30  in a state in which the supply power is bypassed, the closed lever input portion  10   a  is automatically opened, whereby the operator may switch a power supply through the lever input portion  10   a  without a separate process and may perform efficiently a testing operation. 
     A series of process as described above will be described with reference to  FIGS. 8 and 9 . 
       FIG. 8  is a view showing a state in which the alternative supply is bypassed as described above. The lever input portion  10   a  of the automatic transfer switch  10  is in a closed state by a lowering of the opening and closing plate  400 . The operator pulls the automatic transfer switch  10  to the front of the switchboard  30  to remove the automatic transfer switch  10 . The elastic link  300  is provided on the fixed bracket  11 , thereby being drawn with the automatic transfer switch  10 . The contact bar  310  of the elastic link  300  that is pressed in close contact with the straight line portion  230  of the elevation member  200  is moved along the straight line portion  230  and passes through the straight line portion  230  to meet the inclined portion  240 . The contact bar  310  is guided along the inclined portion  240 . Therefore, as shown in  FIG. 9 , the elastic link  300  is turned upward at an angle corresponding to the inclined portion  240 . The elastic link  300  is turned counterclockwise on the drawings, whereby the second end of the elastic link  300  raises the opening and closing plate  400  while being raised so that the lever input portion  10   a  is opened. Then, the operator switches the automatic transfer switch  10  through the lever input portion  10   a  to perform the testing operation. When the testing operation of the automatic transfer switch  10  is completed, the operator pushes the automatic transfer switch  10  into the switchboard  30  so that the automatic transfer switch  10  is returned to an initial location thereof. Accordingly, when the contact bar  310  of the elastic link  300  is moved by being guided along the inclined portion  240  and reaches the straight line portion  230 , the opening and closing plate  400  is lowered again, so that the lever input portion  10   a  of the automatic transfer switch  10  input into the switchboard  30  is closed again. 
     As described above, in the interlock structure of the bypass transfer switching device according to the present disclosure, when the supply power is bypassed, the lever input portion of the automatic transfer switch is automatically closed, and when the automatic transfer switch is drawn from the switchboard when the supply power is bypassed, the lever input portion may be automatically opened. Accordingly, the interlock structure of the present disclosure prevents a safety accident by fundamentally preventing the automatic transfer switch from being manually switched when the supply power is bypassed. In addition, the interlock structure may increase work convenience by the lever input portion automatically opened when the automatic transfer switch is drawn from the switchboard. 
     Although a preferred embodiment of the present disclosure has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.