Abstract:
The present invention implements, through a simple structure, the prevention of an electric shock caused by contacting an output terminal in a conducting state. This electric shock protection structure is provided with: a protective cover ( 40 ) which changes an output terminal into a non-conducting state by pressing a power switch ( 51 ) during the transition of the output terminal from a covered state to an exposed state; and a housing cover ( 60 ) which cannot be moved when the output terminal is in the non-conducting state by having an L-shaped curved section ( 60 A), which is positioned on a different surface from the surface on which the output terminal is disposed, does not contact a contact section ( 44 A) of the protective cover ( 40 ) when the protective cover ( 40 ) exposes the output terminal, and contacts the contact section ( 44 A) when the protective cover ( 40 ) covers the output terminal.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to the technical field of a structure for preventing electric shock to an operator. 
       BACKGROUND ART 
       [0002]    Power supply apparatuses such as electrical storage devices are equipped with a protective cover for preventing an electric shock which covers a power terminal in order to prevent electric shock to a person (an engineer) caused by contact with the power terminal while supplying electric power. A worker who performs power supply work such as cable connecting construction for connecting to the power terminal, for example, turns off power of the power supply apparatus and then removes the protective cover prior to starting the power supply work. If the worker forgets to turn off power in such a situation, an accidental contact with the power terminal may cause an electric shock accident. Therefore, techniques for ensuring safety to prevent electric shock accidents when a worker performs power supply work are required. 
         [0003]    One example of such techniques is disclosed in PTL 1 which is an interlock structure that allows a cover covering an electric component to be moved to a position in which the electric component can be attached/removed only when a disconnector is placed in an off position (a non-conducting state). 
         [0004]    PTL 2 discloses a shutter apparatus that covers a disconnection section of a switch such as a pullout breaker accommodated in a distribution panel. The apparatus is configured so that a shutter plate opens/closes in synchronization with an operation of moving the switch from a pullout position to a connecting position. The operation of inserting the switch into the apparatus opens the shutter plate and the operation of pulling out the switch from the apparatus closes the shutter plate. 
         [0005]    PTL 3 discloses an apparatus configured to allow a battery to be quickly replaced by an easy operation without requiring a tool. The apparatus allows only one of two types of batteries to be removed/attached at a time and allows a battery that is not replaced to automatically supply power to a memory by the removing/attaching operation. 
       CITATION LIST 
     Patent Literature 
       [0006]    [PTL 1] Japanese Laid-open Patent Publication No. 2013-208004 
         [0007]    [PTL 2] Japanese Laid-open Patent Publication No. 2012-120286 
         [0008]    [PTL 3] Japanese Laid-open Utility Model Publication No. 1993(H05)-006683 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0009]    It is the highest priority to ensure safety when power cable connection work or electric component replacement work or the like is performed. It is important to ensure safety to prevent an electric shock accident with a simple structure in terms of cost reduction as well. 
         [0010]    The structure disclosed in PTL 1 controls the protective cover to be moved by an operator only when the disconnector is in the off position. The device disclosed in PTL 2 controls opening and closing of the shutter plate in synchronization with the operation of moving the switch. Accordingly, the techniques disclosed in PTL 1 and PTL 2 are inadequate to solve the problem of ensuring safety to prevent an electric shock accident with a simple structure. In PTL 3, no mention is made of a technique that solve the problem. 
         [0011]    A primary object of the present invention is to provide an electric shock protection structure and method that solve the problem. 
       Solution to Problem 
       [0012]    An electric shock protection structure in one mode of the present invention includes: a switch capable of switching a state of an output terminal in response to a change of a posture of a movable member between a first mode and a second mode caused by an external switching operation; a cover member which is attachable to a surface where the output terminal is provided; and a housing cover, wherein the cover member is in a first state to cover the output terminal when the posture of the movable member is in the first mode while the cover member is attached to the surface, and is capable of being in a second state to expose the output terminal when the posture of the movable member is in the second mode while the cover member is attached to the surface, and the cover member includes a first contact section which, while the cover member is in a process of moving from a position in which the cover member is located in the first state to a position in which the cover member is located in the second state or in a process of being removed from the surface, contacts the movable member and then presses the movable member to change the posture of the movable member from the first mode in which the movable member conducts current to the output terminal to the second mode in which the movable member does not conduct current; and the housing cover is located on a surface different from the surface and, when the cover member is in the first state, a second contact section which is a part of the housing cover contacts a third contact section which is a part of the cover member to prevent the housing cover from moving, and when the cover member is in the second state, the second contact section does not contact the third contact section to allow the housing cover to move. 
         [0013]    In another aspect to achieve the object described above, an electric shock protection method according to one mode of the present invention provides a cover member on a surface where an output terminal is provided and a housing cover on a surface different from the surface, wherein the cover member is in a first state to cover the output terminal when a posture of a movable member of a switch capable of switching a state of the output terminal between a first mode and a second mode in response to an external switching operation is in the first mode while the cover member is provided on the surface where the output terminal is provided, and is capable of being in a second state to expose the output terminal when the posture of the movable member is in the second mode while the cover member is provided on the surface; and, the cover member has a shape including a first contact section which, in a process of moving from a position in which the cover member is located in the first state to a position in which the cover member is in the second state or in a process of removal of the cover member from the surface, contacts the movable member and then presses the movable member to change the posture of the movable member from the first mode in which current is conducted to the output terminal to the second mode in which current is not conducted; and the housing cover includes a second contact section which, when the cover member is in the first state, contacts a third contact section which is a part of the cover member to prevent the housing cover from moving, and when the cover member is in the second state, does not contact the third contact section to allow the housing cover to move. 
       Advantageous Effects of Invention 
       [0014]    The present invention prevents electric shock due to contact with a live output terminal by using a simple structure. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]      FIG. 1  is a perspective view of a power supply apparatus according to a first example embodiment of the present invention (with a protective cover attached). 
           [0016]      FIG. 2  is a perspective view of a front panel of the power supply apparatus according to the first example embodiment of the present invention (with the protective cover removed). 
           [0017]      FIG. 3  is a cross-sectional view of the power supply apparatus according to the first example embodiment of the present invention, taken along line A-A. 
           [0018]      FIG. 4  is a perspective view of a power supply apparatus according to a second example embodiment of the present invention (with a protective cover attached). 
           [0019]      FIG. 5A  is a perspective view of a front panel of the power supply apparatus according to the second example embodiment of the present invention (with the protective cover removed) (1 of 2). 
           [0020]      FIG. 5B  is a perspective view of the front panel of the power supply apparatus according to the second example embodiment of the present invention (with the protective cover removed) (2 of 2). 
           [0021]      FIG. 6  is a front view of the front panel of the power supply apparatus according to the second example embodiment of the present invention (with the protective cover removed). 
           [0022]      FIG. 7  is a perspective view of the protective cover removed from a housing cover in the second example embodiment of the present invention. 
           [0023]      FIG. 8  is a cross-sectional view of the power supply apparatus according to the second example embodiment of the present invention, taken along line B-B. 
           [0024]      FIG. 9  is a cross-sectional view of the power supply apparatus according to the second example embodiment of the present invention, taken along line C-C. 
           [0025]      FIG. 10  is a cross-sectional view illustrating an electric shock protection structure according to a third example embodiment of the present invention, taken along an XY plane. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0026]    Example embodiments of the present invention will be described below in detail with reference to the drawings. In the following descriptions, for convenience of explanation, 3-dimensional coordinate (X-Y-Z) vectors are illustrated in the drawings as appropriate. In the example embodiments described below, the X-axis and Y-axis directions are horizontal directions and the Z-axis direction is the vertical direction. 
       First Example Embodiment 
       [0027]      FIG. 1  is a perspective view of a power supply apparatus  1  according to a first example embodiment with a protective cover  10  attached to the power supply apparatus  1 .  FIG. 2  is a perspective view of the power supply apparatus  1  according to the present example embodiment with the protective cover  10  removed. 
         [0028]    The power supply apparatus  1  supplies power to another electric apparatus through power cables  24  and  25  connected to power terminals  22  and  23 . In the present example embodiment, the power terminal  22  is a negative terminal and the power terminal  23  is a positive terminal. The power terminals  22  and  23  are insulated from a front panel  20  and a housing cover  30  by terminal blocks  220  and  230  made of resin such as plastic. The terminal blocks may be made of any insulating material. 
         [0029]    During power supply from the power supply apparatus  1 , the protective cover  10  is attached to the front panel  20  and the housing cover  30  with screws (not depicted), for example, as illustrated in  FIG. 1  in order to prevent electric shock. When a worker performs power cable connection work, for example, the worker needs to turn off a power switch  21  to stop power supply through the power terminals  22  and  23  before the worker can remove the protective cover  10 . In the present example embodiment, the power switch  21  is in the on state when the power switch  21  is on the positive side of the Z-axis and in the off state when the power switch  21  is on the negative side. 
         [0030]      FIG. 3  illustrates a cross-sectional view of the power supply apparatus  1 , taken along line A-A in  FIG. 1 . The cross-sectional view in  FIG. 3  is a cross-sectional view parallel to an XZ plane. When the protective cover  10  is attached to the power supply apparatus  1 , the protective cover  10  is fixed with screws, for example, with an L-shaped curved section  10 B, which is a part of the protective cover  10 , being inserted in an opening  26  provided in the front panel  20 . 
         [0031]    In the present example embodiment, the direction of removal of the protective cover  10  from the front panel  20  is parallel or substantially parallel to the negative direction of the X-axis as illustrated in  FIG. 3 . During removal of the protective cover  10 , a contact section  10 A which is a part of the protective cover  10  contacts the power switch  21  and then presses the power switch  21  in the removal direction. The power switch  21  pressed by the contact section  10 A turns around a power switch rotation axis  210  and moves in parallel or substantially in parallel to the negative direction of the Z-axis. This places the power switch  21  in the off state and the power supply apparatus  1  stops power supply. 
         [0032]    The power supply apparatus  1  according to the present example embodiment prevents electric shock due to contact with a live power terminal by using a simple structure. The reason is that when the protective cover  10  is removed from the front panel  20 , the protective cover  10  contacts and then presses the power switch  21  to turn the power switch  21  from on to off. 
         [0033]    When a worker performs power supply work during which the worker directly contacts a power feed point in a power supply apparatus, the worker may forget to turn off power, which can result in an electric shock accident. In the power supply apparatus  1  according to the present example embodiment, the protective cover  10  presses the power switch  21  in the process of removal of the protective cover  10 , thereby placing the power switch  21  in the off state. Accordingly, the power supply apparatus  1  prevents occurrence of such an electric shock accident. In addition, the structure included in the power supply apparatus  1  in order to prevent such an electric shock accident is simple. 
         [0034]    The shape and removal direction of the protective cover  10  described and depicted in the present example embodiment are merely illustrative. The protective cover  10  may have a shape different from the shape illustrated in the present example embodiment. Further, the protective cover  10  may be removed in a direction different from a direction parallel or substantially parallel to the negative direction of the X-axis as long as the power switch  21  can be placed in the off state by pressing the power switch  21  in the process of removal of the protective cover  10 . 
         [0035]    In the present invention described using example embodiments thereof as examples, the shape of the power switch is not limited to one that has a turn-style movable member (a toggle), like the power switch  21  according to the present example embodiment. The power switch  21  may have a structure that includes a movable member that moves from one position to another to turn on and off a power supply (a power line). Such a power switch may be any of various types of switches, including a slide-style switch such a DIP switch, or a seesaw switch or a button switch, for example. In this case, the protective cover contacts and then presses the movable member in the process of removal of the protective cover, thereby turning the power switch from on to off. 
         [0036]    An apparatus that can include the electric shock protection structure of the present example embodiment is not limited to a power supply apparatus. The electric shock protection structure according to the present example embodiment is applicable to various electric apparatuses that include an electric component such as a fuse, for example, and have a structure in which an output terminal for feeding power to the electric component is exposed when the electric component is replaced. 
       Second Example Embodiment 
       [0037]      FIG. 4  is a perspective view of a power supply apparatus  2  according to a second example embodiment with a protective cover  40  attached to the power supply apparatus  2 .  FIGS. 5A and 5B  are perspective views of a front panel  50  of the power supply apparatus  2  according to the present example embodiment with the protective cover  40  removed.  FIG. 6  is a front view of the front panel  50  of the power supply apparatus  2  according to the present example embodiment with the protective cover  40  removed. 
         [0038]    Power terminals  52  and  53  are similar to the power terminals  22  and  23  in the first example embodiment. Terminal blocks  520  and  530  are similar to the terminal blocks  220  and  230  of the first example embodiment. The terminal block  520  is fixed to the front panel  50  with screws  521  and  522  and the terminal block  530  is fixed to the front panel  50  with screws  531  and  532 . Power cables  54  and  55  are similar to the power cables  24  and  25  of the first example embodiment. A power switch  51  is similar to the power switch  21  of the first example embodiment. 
         [0039]      FIG. 7  illustrates a perspective view of the protective cover  40  according to the present example embodiment. As illustrated in  FIG. 7 , the protective cover  40  includes guide insertion sections  41  and  42 , an L-shaped curved section  43  and an L-shaped curved section  44 . The guide insertion sections  41  and  42  are tab-shaped and designed to be inserted into guide holes  56  and  57  depicted in  FIGS. 5A, 5B  and  FIG. 6 . The guide holes  56  and  57  are openings formed linearly (in a slit shape) in the front panel  50  in parallel or substantially in parallel to the Z-axis.  FIG. 9  illustrates the guide insertion sections  41  and  42  inserted in the guide holes  56  and  57 .  FIG. 9  is a cross-sectional view of the power supply apparatus  2  in the present example embodiment, which is taken along line C-C in  FIG. 4  and parallel to an XZ plane. 
         [0040]    The protective cover  40  is slidable in parallel or substantially in parallel to the Z-axis on a surface of the front panel  50  without disengaging from the front panel  50  while the guide insertion sections  41  and  42  are inserted in the guide holes  56  and  57 . The guide insertion sections  41  and  42  and the guide holes  56  and  57  have a mechanism that, when the guide insertion section  41  and  42  reaches the end of the guide holes  56  and  57  on the negative side of the Z-axis, allows the guide insertion sections  41  and  42  to be disengaged from the guide holes  56  and  57 . This allows a worker to remove the protective cover  40  from the front panel  50 . 
         [0041]      FIG. 8  illustrates a cross-sectional view of the power supply apparatus  2  taken along line B-B in  FIG. 4 . The cross-sectional view in  FIG. 8  is a cross-sectional view in parallel to an XZ plane. When the protective cover  40  is attached to the power supply apparatus  2 , the protective cover  40  is fixed with the L-shaped curved section  44  being inserted in an opening  58  formed in the front panel  50 . In the present example embodiment, the opening  58  is large enough to provide a space in which the inserted L-shaped curved section  44  can move in parallel or substantially in parallel to the Z-axis as the protective cover  40  slides. 
         [0042]    In the present example embodiment, when a worker removes the protective cover  40 , the worker slides the protective cover  40  in parallel or substantially in parallel to the negative direction of the Z-axis as illustrated in  FIG. 8 . As the protective cover  40  moves in parallel or substantially in parallel to the negative direction of the Z-axis, a contact section  43 A of the L-shaped curved section  43  contacts the switch  51  and then presses the switch  51  in the moving direction. The contact section  43 A is formed perpendicularly or substantially perpendicularly to the Z axis. 
         [0043]    The switch  51  pressed by the contact section  43 A turns around a power switch rotation axis  510  and moves in parallel or substantially in parallel to the negative direction of the Z-axis. This places the power switch  51  in the off state and the power supply apparatus  2  stops power supply. The protective cover  40  can be removed from the front panel  50  after the protective cover  40  reaches the limit position beyond which the protective cover  40  is not allowed to move in parallel or substantially in parallel to the negative direction of the Z-axis. 
         [0044]    As illustrated in  FIGS. 8 and 9 , a housing cover  60  includes an L-shaped curved section  60 A. The L-shaped curved section  60 A is formed perpendicularly or substantially perpendicularly to the X-axis and in parallel or substantially in parallel to the Z-axis. The L-shaped curved section  44  of the protective cover  40  includes a contact section  44 A. Like the L-shaped curved section  60 A, the contact section  44 A is formed perpendicularly or substantially perpendicularly to the X-axis and in parallel or substantially in parallel to the Z-axis. 
         [0045]    The housing cover  60  includes a structure that can be slid in parallel or substantially in parallel to the positive direction of the X-axis when a worker accesses the inside of the housing of the power supply apparatus  2 . When the protective cover  40  is attached to the front panel  50  as illustrated in  FIGS. 8 and 9 , the contact section  44 A is located in a position intersecting an axis parallel or substantially parallel to the X-axis, indicated by the direction in which the L-shaped curved section  60 A moves as the housing cover  60  slides in the +X direction. Accordingly, in this case, the L-shaped curved section  60 A contacts the contact section  44 A to prevent the housing cover  60  from further sliding in the +X direction. 
         [0046]    Further, assume that the worker applies a force in the −X direction in the state described above in order to remove the protective cover  40  from the front panel  50 . In this case, the L-shaped curved section  60 A and the contact section  44 A contact (abut against) each other ( FIG. 8 ). Then an end of the guide insertion section  41  contacts a portion above the slit-shaped opening formed by the guide hole  56  and the guide insertion section  42  contacts a portion above the slit-shaped opening formed by the guide hole  57  ( FIGS. 6, 7 and 9 ). This means that when the worker attempts to remove the protective cover  40  from the front panel  50 , the worker cannot remove the protective cover  40  because of the interference by the structure of the front panel  50  and the housing cover  60  described above. 
         [0047]    The protective cover  40  is attached and fixed to the front panel  50  with screws or a mechanism such as a stopper (not depicted) as illustrated in  FIGS. 8 and 9  when the power supply apparatus  2  is conducting current. Any common technique can be used for the structure that fixes the protective cover  40  to the front panel  50  and therefore description of the fixing structure is omitted from the description and drawings of the present example embodiment. 
         [0048]    When the protective cover  40  is slid in parallel or substantially in parallel to the negative direction of the Z-axis in order to remove the protective cover  40  from the front panel  50 , the contact section  44 A also moves in parallel or substantially in parallel to the negative direction of the Z-axis. As a result, the L-shaped curved section  60 A no longer contacts the contact section  44 A, thereby allowing the housing cover  60  to be slid in substantially parallel to the positive direction of the X-axis. Further, this allows the protective cover  40  to be removed in the −X direction. 
         [0049]    The power supply apparatus  2  according to the present example embodiment prevents electric shock due to contact with a live power terminal by using a simple structure. The reason is that when the protective cover  40  is removed, the protective cover  40  contacts and then presses the power switch  51  to turn the power switch  51  from on to off. 
         [0050]    The protective cover  40  according to the present example embodiment slides on a surface of the front panel  50  along the guide holes  56  and  57  and then can be removed. In the process of the sliding of the protective cover  40 , the contact section  43 A contacts the power switch  51  and then presses the power switch  51  to turn the power switch  51  from on to off. In this way, the power supply apparatus  2  according to the present example embodiment turns the power switch  51  from on to off more reliably than the power supply apparatus  1  according to the first example embodiment. Accordingly, the power supply apparatus  2  according to the present example embodiment further increases the safety against electric shock than the power supply apparatus  1  according to the first example embodiment. 
         [0051]    In addition, the contact section  43 A according to the present example embodiment is formed perpendicularly or substantially perpendicularly to the Z-axis along which the protective cover  40  moves. This allows the contact section  43 A according to the present example embodiment more reliably presses the power switch  51  to turn the power switch  51  from on to off. The protective cover  40  may be a molding made of a material such as plastic. 
         [0052]    While the guide insertion sections  41  and  42  and the guide holes  56  and  57  determine the trajectory of movement of the protective cover  40  in the power supply apparatus  2  according to the present example embodiment, this is merely an example. For example, the front panel  50  may include a guide rail and the protective cover  40  may include a mechanism that moves along the guide rail. 
         [0053]    In the power supply apparatus  2  according to the present example embodiment, the contact section  44 A is located close to the L-shaped curved section  60 A while the protective cover  40  covers the power terminals  52  and  53  ( FIGS. 8 and 9 ). Therefore, when a worker attempts to slide the housing cover  60 , these components contact each other to interfere the sliding. In this way, the power supply apparatus  2  according to the present example embodiment prevents the worker from sliding the housing cover  60  to access the inside of the housing of the power supply apparatus  2  and get electric shock while the power supply apparatus  2  is conducting current. Thus, the power supply apparatus  2  improves safety against electric shock with a simple structure. 
         [0054]    The contact section  44 A and the L-shaped curved section  60 A according to the present example embodiment are formed in parallel or substantially in parallel to the Z-axis along which the protective cover  40  moves and perpendicularly or substantially perpendicularly to the X-axis along which the housing cover  60  moves. This allows the power supply apparatus  2  according to the present example embodiment to cause the contact section  44 A and the L-shaped curved section  60 A to interfere to prevent the housing cover  60  from sliding when the power supply apparatus  2  is conducting current, and allows the power supply apparatus  2  to reliably eliminate the interference when the power supply apparatus  2  is not conducting current. 
       Third Example Embodiment 
       [0055]      FIG. 10  is a cross-sectional view of an electric shock protection structure  3  according to a third example embodiment, taken along an XY plane. 
         [0056]    The electric shock protection structure  3  according to the present example embodiment includes a switch  80  and a cover member  70 . 
         [0057]    The switch  80  is capable of switching a state of an output terminal  81  in response to a change of the posture of a movable member between a first mode  80 A and a second mode  80 B caused by an external switching operation. 
         [0058]    The cover member  70  can be attached to a surface  82  on which the output terminal  81  is provided. When the posture of the movable member is in the first mode  80 A while the cover member  70  is attached to the surface  82 , the cover member  70  is in a first state to cover the output terminal  81 . When the posture of the movable member is in the second mode  80 B while the cover member  70  is attached to the surface  82 , the cover member  70  can be in a second state to expose the output terminal  81 . 
         [0059]    The cover member  70  has a shape that, in a certain process, presses the movable member to change the posture of the movable member from the first mode  80 A in which current is conducted to the output terminal  81  (the power-on state) to the second mode  80 B which is non-conducting state (the power-off state). The certain process is the process of transition of the cover member  70  from the first state to the second state or the process of removal of the cover member  70  from the surface  82 . 
         [0060]    The electric shock protection structure  3  according to the present example embodiment prevents electric shock due to contact with a live output terminal by using a simple structure. The reason is that when the cover member  70  transitions to expose the output terminal  81 , the cover member  70  contacts and then presses the switch  80  to turn the switch  80  from on to off. 
         [0061]    While the invention has been particularly shown and described with reference to example embodiments thereof, the invention is not limited to these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the claims. 
         [0062]    This application is based upon and claims the benefit of priority from Japanese patent application No. 2014-189909, filed on Sep. 18, 2014, the disclosure of which is incorporated herein in its entirety by reference. 
       REFERENCE SIGNS LIST 
       [0063]      1  Power supply apparatus 
         [0064]      10  Protective cover 
         [0065]      10 A Contact section 
         [0066]      10 B L-shaped curved section 
         [0067]      20  Front panel 
         [0068]      21  Power switch 
         [0069]      210  Power switch rotation axis 
         [0070]      22  and  23  Power terminal 
         [0071]      220  and  230  Terminal block 
         [0072]      24  and  25  Power cable 
         [0073]      26  Opening 
         [0074]      30  Housing cover 
         [0075]      2  Power supply apparatus 
         [0076]      40  Protective cover 
         [0077]      41  and  42  Guide insertion section 
         [0078]      43  L-shaped curved section 
         [0079]      43 A Contact section 
         [0080]      44  L-shaped curved section 
         [0081]      44 A Contact section 
         [0082]      50  Front panel 
         [0083]      51  Power switch 
         [0084]      510  Power switch rotation axis 
         [0085]      52  and  53  Power terminal 
         [0086]      520  and  530  Terminal block 
         [0087]      521  and  522  Screw 
         [0088]      531  and  532  Screw 
         [0089]      54  and  55  Power cable 
         [0090]      56  and  57  Guide hole 
         [0091]      58  Opening 
         [0092]      60  Housing cover 
         [0093]      60 A L-shaped curved section 
         [0094]      3  Electric shock protection structure 
         [0095]      70  Cover member 
         [0096]      80  Switch 
         [0097]      80 A First mode 
         [0098]      80 B Second mode 
         [0099]      81  Output terminal 
         [0100]      82  Surface