Patent Publication Number: US-2023154711-A1

Title: Entrance and exit position detection device for power device, and entrance and exit monitoring system including same

Description:
FIELD 
     The present disclosure relates to a device for detecting extended and retracted positions and a system for monitoring extending and retracting motions having the same. More specifically, the present disclosure relates to a device for detecting extended and retracted positions for a power device, the device being capable of linearly detecting extended and retracted positions of a circuit breaker body in a cradle, and a system for monitoring extending and retracting motions having the same. 
     DESCRIPTION OF RELATED ART 
     A circuit breaker is a device that breaks a circuit when an abnormal or fault current occurs in an electric circuit, thereby protecting a load and a power source therefrom. 
     An air circuit breaker is a kind of a circuit breaker that cuts off current in event of opening and closing a load or an accident such as grounding or short circuit in transmission, a substation or an electric circuit, etc. The air circuit breaker is mainly used for a low voltage device. 
     The circuit breaker includes a cradle to facilitate inspection, use, or replacement of a circuit breaker body. 
     The circuit breaker may be classified into a fixed type circuit breaker in which the circuit breaker body is fixed to the cradle, and a drawable type circuit breaker in which the circuit breaker body is drawn into (retracts into) and drawn out of (extends from) the cradle. 
     In the drawable type circuit breaker, the circuit breaker body retracts into the cradle to conduct the current. In this drawn-in state, the circuit breaker performs insertion (on) and trip (off) operations. When fault current occurs in an electrical line while the circuit breaker is inserted (on), the circuit breaker cuts the fault current after a predefined time or immediately depending on a magnitude of the fault current. 
       FIG.  1    shows a configuration diagram of a conventional power device. 
     Referring to  FIG.  1   , a conventional power device  10  includes a circuit breaker body  13 , a cradle  11  into which the circuit breaker body  13  moves, a handle receiving portion  15  into which a handle  17  is inserted, and the handle  17  which is inserted into the handle receiving portion  15 , and then is rotated so that the circuit the circuit breaker body  13  moves to a disconnect position, a test position, a connect position, etc. 
     Therefore, when the handle  17  is inserted into the handle receiving portion  15  and is rotated while the circuit breaker body  13  is positioned inside the cradle  11 , the circuit breaker body  13  is positioned at the disconnect position, the test position or the connect position in the cradle  11 . 
       FIG.  2    is a front view showing a position display device provided in another conventional power device. 
     Referring to  FIG.  2   , the conventional power device includes a position display device  30 . Accordingly, a position of the circuit breaker body is displayed externally on the position display device  30 . 
     However, in the position display device  30  of the conventional power device, the handle receiving portion  33  is positioned above an indicator  31 . Thus, when adjusting the position of the circuit breaker body  13  using the handle  17 , the indicator  31  is hidden with the handle  17 , so that it is difficult to accurately identify a current position of the circuit breaker body  13 . 
     For this reason, a rotational motion of a worm wheel is converted into a linear motion to position the indicator above the handle receiving portion. However, in this case, the position of the circuit breaker body  13  may be identified only when the circuit breaker body  13  is at the disconnect position, the test position or the connect position within the cradle  11 . 
     Accordingly, there is a problem in the prior art in that it is practically difficult to linearly detect the position of the body while the circuit breaker body is approaching the disconnect position, the test position, or the connect position in the cradle. 
     A prior literature related to the present disclosure includes a Korean patent No. 10-1151940. 
     DISCLOSURE 
     Technical Purposes 
     A first purpose of the present disclosure is to provide a device for detecting extended and retracted positions for a power device, the device being capable of linearly detecting extended and retracted positions of a circuit breaker body in a cradle, and to provide a system for monitoring extending and retracting motions having the same. 
     Further, a second purpose of the present disclosure is to provide a device for detecting extended and retracted positions for a power device, the device being capable of detecting position information of a circuit breaker body while the circuit breaker body retracts into or extends from a cradle in real time, and to provide a system for monitoring extending and retracting motions having the same. 
     Purposes according to the present disclosure are not limited to the above-mentioned purpose. Other purposes and advantages according to the present disclosure that are not mentioned may be understood based on following descriptions, and may be more clearly understood based on embodiments according to the present disclosure. Further, it will be easily understood that the purposes and advantages according to the present disclosure may be realized using means shown in the claims and combinations thereof. 
     Technical Solutions 
     The present disclosure provides a device for detecting extended and retracted positions for a power device. 
     The device for detecting extended and retracted positions for a power device includes a cradle having one open side, and having a placement space defend therein; a guide plate movably disposed in the placement space, wherein a power device body is seated on the guide plate; and a position detector configured to linearly detect a displaced position of the power device body while the power device body seated on the guide plate retracts into or extends from the cradle. 
     In this regard, a guide hole is defined in a side face of the cradle, wherein the guide hole has a predefined length and extends along a horizontal direction, 
     wherein the position detector includes: 
     a position detecting member attached to a predefined area of a side face of the cradle exposed to the guide hole, wherein the position detecting member has a reflective area, wherein an amount of light reflected from the reflective area varies along a longitudinal direction thereof; and 
     an optical sensor installed in the cradle so as to be disposed adjacent to the guide hole, wherein the optical sensor is configured to emit light to the reflective area of the position detecting member, and measure an amount of light reflected therefrom, and measure the displaced position of the power device body based on the measured amount. 
     Further, the reflective area is embodied as at least one of: 
     a gradation sticker; or an inclined member having an inclined face gradually upwardly or downwardly inclined in a direction from one end to the other end of the reflective area. 
     Further, a curved hole having a preset curvature is defined in a side face of the cradle, 
     wherein a contact pin connected to a link disposed inside the cradle is positioned in the curved hole in a protruding manner therefrom, 
     and the contact pin is movable along the curved hole, 
     wherein the contact pin is displaced along the curved hole while the power device body retracts into or extends from the cradle, 
     wherein the position detector includes: 
     a position detecting member extending in a curved manner along a length direction of the curved hole and having a predetermined curvature, wherein the position detecting member is disposed in an area adjacent to the curved hole, and has a reflective area, wherein an amount of light reflected from the reflective area varies along a longitudinal direction thereof; and 
     an optical sensor installed on the contact pin, wherein the optical sensor is configured to emit light to the reflective area of the position detecting member, and measure an amount of light reflected therefrom, and measure the displaced position of the power device body based on the measured amount. 
     Further, the reflective area is embodied as at least one of: a gradation sticker; or an inclined member having an inclined face gradually upwardly or downwardly inclined in a direction from one end to the other end of the reflective area. 
     Another aspect of the present disclosure provides a system for monitoring extending and retracting motions, the system comprising: the device for detecting extended and retracted positions for the power device as described above; a storage for receiving the linearly-detected displaced position of the power device body from the position detector and storing the displaced position therein; a display for displaying the stored displaced position of the power device body to an outside; and a controller configured to control the display to display a preset position and the stored displaced position of the power device body in an overlapping manner with each other. 
     Technical Effects 
     Based on the above technical solutions, the device according to the present disclosure has an effect of linearly detecting the extended and retracted positions of the circuit breaker body in the cradle. 
     Further, the device and the system according to the present disclosure may be capable of detecting position information of the circuit breaker body while the circuit breaker body retracts into or extends from the cradle in real time, and may be capable of monitoring extending and retracting motions. 
     In addition to the above-described effects, specific effects of the present disclosure will be described together while describing specific details for carrying out the disclosure below. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram showing a configuration of a conventional power device. 
         FIG.  2    is a front view showing a position display device provided in another conventional power device. 
         FIG.  3    is a perspective view showing a coupling relationship between a cradle and a circuit breaker body according to the present disclosure. 
         FIG.  4    is a perspective view showing a state in which the circuit breaker body is inserted into a receiving space of the cradle according to the present disclosure. 
         FIG.  5    is a diagram showing a first example of a position detecting member in an example of a position detector according to the present disclosure. 
         FIG.  6    is a diagram showing a second example of a position detecting member according to the present disclosure. 
         FIG.  7    is a perspective view showing another embodiment of a position detector according to the present disclosure. 
         FIG.  8    is a view showing a first example of a position detecting member in another embodiment of a position detector according to the present disclosure. 
         FIG.  9    is a diagram showing a second example of a position detecting member according to the present disclosure. 
         FIG.  10    is a cross-sectional view taken along a line A-A of  FIG.  9   . 
         FIG.  11    illustrates a system for monitoring extending and retracting motions according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTIONS 
     Hereinafter, with reference to the drawings, an embodiment of the present disclosure will be described in detail so that a person of ordinary skill in the art to which the present disclosure belongs may easily implement the present disclosure. 
     The present disclosure may be implemented in several different forms and is not limited to the embodiment as described herein. 
     In describing the present disclosure, when it is determined that a detailed description of a known component related to the present disclosure may unnecessarily obscure gist the present disclosure, the detailed description is omitted. In the drawings, the same reference numerals are used to indicate the same or similar elements. 
     In addition, it will also be understood that when a first element or layer is referred to as being present “on” or “beneath” a second element or layer, the first element may be disposed directly on or beneath the second element or may be disposed indirectly on or beneath the second element. 
     It will also be understood that when a first element or layer is referred to as being present “on” or “beneath” a second element or layer, a third element or layer may be disposed between the first and second elements or layers. 
     Hereinafter, with reference to the accompanying drawings, a device for detecting extended and retracted positions for a power device according to the present disclosure and a system for monitoring extending and retracting motions having the same will be described. 
       FIG.  3    is a perspective view showing a coupling relationship between a cradle and a circuit breaker body according to the present disclosure.  FIG.  4    is a perspective view showing a state in which the circuit breaker body is inserted into a receiving space of the cradle according to the present disclosure.  FIG.  5    is a diagram showing a first example of a position detecting member in an example of a position detector according to the present disclosure.  FIG.  6    is a diagram showing a second example of a position detecting member according to the present disclosure. 
     Referring to  FIG.  3   , a device for detecting extended and retracted positions according to the present disclosure includes a cradle  100 , a circuit breaker body  200 , and a position detector  300 . 
     A receiving space is defined inside the cradle  100  according to the present disclosure. A front face of the cradle  100  is open. The receiving space is a space into which the circuit breaker body  200  is introduced. 
     A disconnect position, a test position, or a connect position is preset in the receiving space, based on a position to which the circuit breaker body  200  moves. In this regard, a distance between adjacent ones of the disconnect position, the test position and the connect position is preset. This distance is referred to as a movement distance. 
     A guide plate  210  are disposed on each of both opposing sides of the cradle  100 . The circuit breaker body  200  is seated on the cradle  100 . The guide plate  210  is movably disposed in an placement space formed inside the cradle  100 . Accordingly, since the circuit breaker body  100  is seated on the guide plate  210 , movement of the guide plate  210  leads to movement of the circuit breaker body  100 . 
     The guide plate  210  has a predefined length along a horizontal direction and a predefined width along a vertical direction. 
     Further, a guide hole  110  having a predefined length along the horizontal direction is cut and formed in each of both opposing walls of the cradle  100 . 
     The length of the guide hole  110  may be equal to the above-described movement distance. 
     Further, an outer face of the guide plate  210  may be exposed to an outside through the guide hole  110 . 
     Accordingly, a partial area of the outer face of the guide plate  210  is exposed to the outside through the guide hole  110 . 
     In this regard, the partial area of the outer face of the guide plate  210  exposed through the guide hole  110  is referred to as an installation area. 
     The position detector  300  according to the present disclosure linearly detects a position in movement of the guide plate  210  while the guide plate  210  on which the circuit breaker body  200  is seated is drawn in and out of the placement space of the cradle  100 . 
     The position detector  300  includes a position detecting member  310  and an optical sensor  320 . 
     The position detecting member  310  is attached to the above-described installation area. The attachment scheme may include a coupling scheme using bolts or the like, and a scheme of attaching using an adhesive. 
     Referring to  FIG.  5   , the position detecting member  310  according to the present disclosure is attached to a predefined area of a side face of the guide plate  210  exposed to the guide hole  110 . The position detecting member  310  has a reflective area  311  in which an amount of light as reflected varies along a longitudinal direction thereof. 
     The position detecting member  310  is attached to the installation area of the side face of the guide plate  210 . 
     The optical sensor  320  is installed in the cradle  100  so as to be disposed in the vicinity of the guide hole  110 , and emits light to the reflective area of the position detecting member  310  to measures an amount of light reflected therefrom and thus determine a displaced position of the circuit breaker body  200  based on the measured amount. 
     A bracket  321  is installed at a predefined position near the guide hole  110 . The bracket  321  may be a member extending laterally from a predefined position in the vicinity of the guide hole  110  so as to be positioned at a position overlapping the guide hole  110 . The optical sensor  320  is fixedly installed on the bracket  321  so as to be exposed to the guide hole  110 . 
     In this regard, the reflective area  311  may be embodied as a gradation sticker. Further, the position detecting member  310  may be embodied as a reflective sticker in which gradation is formed on an outer face thereof. 
     Thus, a position of the circuit breaker body  200  is linearly displaced inside the cradle  100  while the circuit breaker body  200  retracts into or extends from the receiving space. 
     In this regard, the optical sensor  320  fixed to one position has a light-emitter and a light-receiver. 
     The light-emitter irradiates light to the reflective area  311  as the gradation area. Then, the light reflected from the reflective area  311  is received by the light-receiver. An amount of the reflected light is measured by the light-receiver. 
     For example, the reflective area  311  has a predefined length and is embodied as a gradation area. Thus, the amount of reflected light therefrom may vary based on a position of the reflective area. 
     Accordingly, the reflective area  311  may be implemented such that the amount of light as reflected therefrom gradually increases or decreases in a direction from one end of the reflective area  311  to the other end thereof. 
     As a result, the position detecting member  310  is displaced simultaneously with the movement of the guide plate  210  onto which the moving circuit breaker body  200  is seated. Thus, an amount of reflected light from a predefined position of the reflective area  311  may be measured by the optical sensor, and a displaced position of the circuit breaker body  200  may be easily detected by the optical sensor, based on the measured amount of reflected light. 
     Further, the device according to the present disclosure may detect position information about three positions of the circuit breaker body  200 , that is, the disconnect position, the test position, and the connect position, and may linearly detect a displaced position of the body within a predefined movement range, thereby detecting an accurate displaced position of the circuit breaker body  200 . 
     In one example, referring to  FIG.  6   , the position detecting member  310  according to the present disclosure is attached to the predefined area of the side face of the guide plate  210  exposed to the guide hole  110 . The position detecting member  310  has the reflective area  312  in which an amount of light reflected therefrom varies based on along the length direction thereof. 
     The position detecting member  310  is attached to the installation area of the side face of the guide plate  210 . 
     The optical sensor  320  is installed in the cradle  100  so as to be disposed in the vicinity of the guide hole  110 . The optical sensor  320  emits light to the reflective area  312  of the position detecting member  310  and measures the amount of reflected light therefrom, and measures the displaced position of the guide plate  210  on which the circuit breaker body  200  is mounted. 
     In this regard, the reflective area  312  may be embodied as an inclined member with an inclined face  312   a  inclined in a direction from one end to the other end. 
     Thus, while the circuit breaker body  200  retracts into or extends from the receiving space while being seated on the guide plate  210 , the position of the guide plate  210  is linearly displaced inside the cradle  100 . 
     In this regard, the optical sensor  320  fixed to one position has the light-emitter and the light-receiver. 
     The light-emitter irradiates light to the moving inclined face  312   a . Then, the light reflected from the inclined face  312   a  is received by the light-receiver and the amount of reflected light is measured by the light-receiver. 
     For example, the inclined member has a predefined length and has the inclined face  312   a . Thus, the amount of reflected light therefrom varies based on a position on the reflective area  312 . 
     Therefore, the inclined member may be implemented such that the amount of light reflected from the inclined face  312   a  gradually increases or decreases in a direction from one end of the inclined face  312   a  to the other end thereof. 
     The position detecting member  310  is displaced simultaneously with the movement of the guide plate  210  onto which the moving circuit breaker body  200  is seated. Thus, an amount of reflected light from a predefined position of the reflective area  311  may be measured by the optical sensor, and a displaced position of the circuit breaker body  200  may be easily detected by the optical sensor, based on the measured amount of reflected light. 
     Further, the device according to the present disclosure may detect position information about three positions of the circuit breaker body  200 , that is, the disconnect position, the test position, and the connect position, and may linearly detect a displaced position of the body within a predefined movement range, thereby detecting an accurate displaced position of the circuit breaker body  200 . 
     When the inclined member is used, a distance to the inclined face  312   a  may be measured by the optical sensor, and the displaced position of the circuit breaker may be detected by the optical sensor, based on this measured distance value. 
       FIG.  7    is a perspective view showing another embodiment of a position detector according to the present disclosure.  FIG.  8    is a diagram showing a first example of a position detecting member in another example of a position detector according to the present disclosure.  FIG.  9    is a diagram showing a second example of a position detecting member according to the present disclosure.  FIG.  10    is a cross-sectional view taken along a line A-A of  FIG.  9   . 
     Referring to  FIG.  7    and  FIG.  8   , a curved hole  120  having a set curvature is defined in a side face of the cradle  100  according to the present disclosure. 
     A contact pin  130  disposed inside the cradle  100  and connected to a link (not shown) connected to the circuit breaker body  200  is inserted into and protrudes from the curved hole  120  and is movable along the curved hole  120 . Accordingly, movement of the contact pin  130  is associated with the movement of the circuit breaker body  200 . 
     The contact pin  130  is displaced along the curved hole  120  as the circuit breaker body  200  retracts into or extends from the receiving space. 
     A position detector  400  includes a position detecting member  410  having a predetermined curvature along a length direction of the curved hole  120 , and disposed adjacent to the curved hole  120 , and having a reflective area  411  in which an amount of light reflected therefrom varies in a length direction thereof, and an optical sensor  420  installed on the contact pin  130 . The optical sensor  420  emits light to the reflective area  411  of the position detecting member  410  and measures an amount of reflected light therefrom and measures a displaced position of the circuit breaker body  200  based on the measured amount. 
     The position detecting member  410  is installed on an outer face of the cradle  100  and along a curvature of the curved hole  120  and in an area adjacent to the curved hole  120 . 
     The optical sensor  400  is installed on the contact pin  130 . The optical sensor  400  has a light-emitter and a light-receiver. The optical sensor  400  is fixed at a position of the contact pin  130  set such that the sensor  400  is capable of emitting light to and receiving light from the reflective area  411 . 
     A bracket  421  extending laterally is installed on an upper end of the contact pin  130 . The bracket  421  may be exposed to the curved hole  120 . The optical sensor  420  is fixedly installed on the bracket  421 . The optical sensor  420  may be exposed to the curved hole  120 . 
     The optical sensor  420  may emit light to the reflective area  411  of the position detecting member  410  and may measure the amount of reflected light therefrom, and may determine the displaced position of the circuit breaker body  200  based on the measured amount. 
     In this regard, the reflective area  411  may be embodied as a gradation sticker. Further, the position detecting member  410  may be embodied as a reflective sticker in which gradation is formed on an outer face thereof The sticker is a curved sticker. 
     Thus, the position of the circuit breaker body  200  is linearly displaced inside the cradle  100  while the circuit breaker body  200  retracts into or extends from the receiving space. 
     At this time, the contact pin  130  is displaced along the curved hole  120 . In this regard, the optical sensor  400  installed on the contact pin  130  has the light-emitter and the light-receiver. 
     The light-emitter irradiates light to the reflective area  411  as a moving gradation area. Then, the light reflected from the reflective area  411  is received by the light-receiver and the amount of reflected light therefrom is measured thereby. 
     For example, the reflective area  411  has a predefined length and is embodied as a gradation area. Thus, the amount of reflected light therefrom may vary based on a position of the reflective area  411 . 
     Accordingly, the reflective area  411  may be implemented such that the amount of light as reflected therefrom gradually increases or decreases in a direction from one end of the reflective area  411  to the other end thereof. 
     Therefore, the optical sensor  420  is attached to the contact pin  130  and is displaced along therewith, such that the sensor  420  measures the amount of reflected light from a predefined position of the reflective area  411  during the movement of the sensor  420 . Thus, the displaced position of the circuit breaker body  200  may be easily detected by the sensor based on the measured amount of the reflected light. 
     Further, the device according to the present disclosure may detect position information about three positions of the circuit breaker body  200 , that is, the disconnect position, the test position, and the connect position, and may linearly detect a displaced position of the body within a predefined movement range, thereby detecting an accurate displaced position of the circuit breaker body  200 . 
     In one example, referring to  FIG.  9    and  FIG.  10   , the position detecting member  410  according to the present disclosure is installed in the area adjacent to the curved hole  120 . The position detecting member  410  has the same curvature as that of the curved hole  120 . 
     The optical sensor  400  is installed on the contact pin  130 , and emits light to the position detecting member  410  and measures the amount of reflected light therefrom and measures the displaced position of the circuit breaker body  200  based on the measured amount. 
     In this regard, the reflective area  412  may be embodied as an inclined member with an inclined face  412   a  inclined in a direction from one end to the other end. 
     Thus, while the circuit breaker body  200  retracts into or extends from the receiving space while being seated on the guide plate  210 , the position of the guide plate  210  is linearly displaced inside the cradle  100 . 
     In this regard, the optical sensor  320  fixed to one position has the light-emitter and the light-receiver. 
     The light-emitter irradiates light to the moving inclined face  412   a . Then, the light reflected from the inclined face  412   a  is received by the light-receiver and the amount of reflected light is measured by the light-receiver. 
     For example, the inclined member has a predefined length and has the inclined face  412   a . Thus, the amount of reflected light therefrom varies based on a position on the reflective area  412 . 
     Therefore, the inclined member may be implemented such that the amount of light reflected from the inclined face  412   a  gradually increases or decreases in a direction from one end of the inclined face  412   a  to the other end thereof. 
     The position detecting member  410  is displaced simultaneously with the movement of the guide plate  210  onto which the moving circuit breaker body  200  is seated. Thus, an amount of reflected light from a predefined position of the reflective area  311  may be measured by the optical sensor, and a displaced position of the circuit breaker body  200  may be easily detected by the optical sensor, based on the measured amount of reflected light. 
     Further, the device according to the present disclosure may detect position information about three positions of the circuit breaker body  200 , that is, the disconnect position, the test position, and the connect position, and may linearly detect a displaced position of the body within a predefined movement range, thereby detecting an accurate displaced position of the circuit breaker body  200 . 
     When the inclined member is used, the distance to the inclined face  412   a  may be measured by the optical sensor, and the displaced position of the circuit breaker may be detected by the optical sensor, based on this measured distance value. 
       FIG.  11    illustrates a system for monitoring extending and retracting motions according to the present disclosure. 
     Referring to  FIG.  11   , a system for monitoring extending and retracting motions according to the present disclosure includes a device for detecting the above-described extended and retracted positions. 
     The system for monitoring the extending and retracting motions includes a storage  500  configured to receive the displaced position of the circuit breaker body  200  as linearly detected using the position detector  300  or  400 , and to store the displaced position therein; a display  600  that externally displays the stored displaced position of the circuit breaker body  200 ; and a controller  700  that controls the display  600  to display the three preset positions and the stored displaced position of the circuit breaker body  200  in an overlapping manner with each other. 
     As described above, the position detector  300  or  400  according to the present disclosure may transmit information about the displaced position of the circuit breaker body  200  to the storage  500  while the circuit breaker body  200  is being drawn into or withdrawn out of the receiving space of the cradle  100 . 
     The storage  500  stores the displaced position information of the moving circuit breaker body  200  in real time. The display  600  visually displays the displaced position or the displaced position information stored in the storage. 
     Accordingly, an operator may visually identify the displaced position of the circuit breaker body  200  inside the cradle  100 . 
     Further, according to the present disclosure, the controller  700  controls the display  600  to display the three preset positions and the stored displaced position of the circuit breaker body  200  in an overlapping manner with each other so that the operator may identify in real time whether the circuit breaker body is accurately positioned at each of the three set positions. 
     In this regard, when each of the three set positions and an actual displaced position of the circuit breaker body  200  do not coincide with each other, the operator may use a device such as a handle to forcibly correct the position of the circuit breaker body  200 , or may forcibly move the circuit breaker body  200  using a separate movement device to correct the position thereof. 
     Accordingly, the device according to the present disclosure linearly detects the position of the circuit breaker body  200  which is displaced inside the cradle  100 . The system may allow the operator to identify whether the circuit breaker body  200  is positioned at each of the preset operating positions and to correct a position mismatch. 
     The specific embodiments regarding the present disclosure have been described above. However, it is obvious that various implementation modifications may be made as long as each thereof does not deviate from the scope of the present disclosure. 
     Therefore, the scope of the present disclosure should not be limited to the described embodiments and should be defined by the claims as described below as well as equivalents thereto. 
     That is, it should be understood that the above-described embodiments are not restrictive but illustrative in all respects, and the scope of the present disclosure is indicated by the claims to be described later rather than the detailed descriptions. Any changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present disclosure.