Patent Publication Number: US-2023133635-A1

Title: Interlocking mechanism for a switching device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 63/273,615, filed Oct. 29, 2021. The disclosure of the priority application in its entirety is hereby incorporated by reference into the presence application. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to a switching device. More specifically, the present disclosure relates to an interlocking mechanism for conditionally allowing operation of the switching device. 
     BACKGROUND 
     Switching devices, such as, electrical switches, are used to control flow of electrical current. For example, electrical switches form an electrical connection allowing flow of current when switched on and interrupt an electrical connection disrupting the flow of current when switched off. Electrical switches are generally enclosed in cabinets that have an operating handle located outside the cabinets. The operating handle is used to operate the electrical switch. For example, the operating handle is rotated to an off position to interrupt a connection and is rotated to an on position to form an electrical connection. There may be a need for a mechanism that conditionally allows operation of the electrical switches. 
     SUMMARY 
     One aspect of the present disclosure relates to an interlocking mechanism for a switching device. The interlocking mechanism can include an interlocking arm that has a first end and a second end. The interlocking arm can be movable between a first position and a second position. When positioned in the first position, the first end of the interlocking arm forms a releasable contact with a switch operating mechanism of a switching device to block operation of the switching device. When positioned in the second position, the first end of the interlocking arm withdraws from the releasable contact with the switch operating mechanism of the switching device to allow operation of the switching device. The interlocking mechanism further includes an actuator connected to the interlocking arm. The actuator, in response to receiving an actuator signal, moves the interlocking arm between the first position and the second position. 
     Another aspect of the present disclosure relates to a switching device that includes a cabinet and a switch control handle mounted outside the cabinet. The switch control handle can be pivotally movable about a handle axis between an off position and an on position. The switching device can further include a circuit unit mounted inside the cabinet and an actuator shaft connected to the circuit unit. The actuator shaft shifts the circuit unit to an open configuration when the switch control handle moves to the off position and shifts the circuit unit to a closed configuration when the switch control handle moves to the on position. The switching device can further include a crank member that can be pivoted at the handle axis and connected to the switch control handle. The switching device further includes an interlocking arm having a first end and a second end. The interlocking arm is movable between a first position and a second position. When positioned in the first position, the first end of the interlocking arm forms a releasable contact with the crank member to block pivotal movement of the switch control handle at the handle axis. When positioned in the second position, the first end of the interlocking arm withdraws from the releasable contact with the crank member to allow operation of the switch control handle. The switching device further includes an actuator connected to the interlocking arm. The actuator, in response to receiving an actuator signal, moves the interlocking arm between the first position and the second position. 
     Yet another aspect of the present disclosure relates to a method of operating a switching device. The method includes steps of: determining that a pre-determined condition for operating a switching device is met; generating, in response to determining that the pre-determined condition for the switching device is met, an actuator signal; and sending the actuator signal to an actuator connected to an interlocking arm of an interlocking device, the actuator, in response to receiving the actuator signal, moves the interlocking arm from a first position to a second position, wherein the interlocking arm includes a first end and a second end, wherein when positioned in the first position, the first end of the interlocking arm forms a releasable contact with the switch operating mechanism of the switching device to block operation of the switching device, and when positioned in the second position, the second end of the interlocking arm withdraws from the releasable contact with the switch operating mechanism of the switching device to allow operation of the switching device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings which are incorporated in and constitute a part of the description, illustrate several aspects of the disclosure. A brief description of the drawings is as follows: 
         FIGS.  1 - 2    illustrate an interlocking mechanism for a switching device in accordance with principles of the present disclosure. 
         FIG.  3    illustrates interlocking mechanism of  FIG.  1    with a different interlocking arm in accordance with the principles of the present disclosure. 
         FIG.  4    illustrates the interlocking mechanism of  FIGS.  1 - 3    retracted from a releasable contact with a switch operating mechanism of a switching device. 
         FIG.  5    illustrate the interlocking mechanism of  FIGS.  1 - 3    forming a releasable contact with the switch operating mechanism of a switching device. 
         FIGS.  6 A and  6 B  illustrate door safety mechanism of a switching device. 
         FIG.  7    illustrates a switching device with switching units. 
         FIG.  8    illustrates an example enclosure for housing the switching device of  FIG.  6   . 
         FIG.  9    illustrate an example defeat mechanism for the interlocking mechanism of  FIGS.  1 - 3    in accordance with the principles of the present disclosure. 
         FIG.  10    illustrates a flow diagram of a method for operating a switching device in accordance with the principles of the present disclosure. 
     
    
    
     DETAIL DESCRIPTION 
     Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like structure. 
     A switching device (for example, electrical switch or a disconnect device) is typically used for controlling a flow of current by forming or interrupting an electrical connection. A switching device is generally housed in a cabinet or a box. The cabinet has an operating handle (also referred to as an operating lever or a switch handle) located outside the cabinet to operate the switching device. The operating handle is rotated along a pivot axis to an off position to interrupt an electrical connection and is rotated to an on position to an electrical connection. Some applications may require one or more pre-determined criteria to be met before the electrical connection is interrupted or formed. 
     This disclosure provides an interlocking mechanism for selective operation of a switching device. For example, and as discussed in greater detail in the following sections of the disclosure, the interlocking mechanism disclosed herein allows the operation of the switching device when one or more pre-determined criteria for forming or interrupting the electrical connection is met. 
       FIG.  1    illustrate an interlocking mechanism  100  for a switching device, for example, a switching device  220  shown in  FIG.  7   . Interlocking mechanism  100  includes an interlocking arm  102  having a first end  104  and a second end  106 . Interlocking arm  102  is movable or rotatable in an arc between a first position and a second position. In examples, when interlocking arm  102  is in the first position, first end  104  of interlocking arm  102  forms a releasable contact (shown in  FIG.  4   ) with a switch operating mechanism (for example, a switch operating mechanism  200  shown in  FIGS.  4 - 5   ) of switching device  220  thereby preventing the operation of switching device  220 . When interlocking arm  102  is moved or rotated to the second position, first end  104  of interlocking arm  102  disengages or retracts from the releasable contact (shown in  FIG.  5   ) with switch operating mechanism  200  thereby allowing the operation of switching device  220 . 
     In examples, interlocking arm  102  is moved or rotated between the first position and the second position through an actuator  108 . Actuator  108  is connected to second end  106  of interlocking arm  102 . In some examples, actuator  108  includes an actuator plunger  110 . In such examples, second end  106  of interlocking arm  102  is connected to actuator  108  through actuator plunger  110 . 
     In some examples, actuator  108  can include a solenoid. The solenoid of actuator  108  can include a coil of a metal wire. When actuator  108  is energized, that is, when electrical current flows through the coil, a magnetic field is formed around the coil which draws actuator plunger  110  inwards that causes interlocking arm  102  to move or rotate from the first position to the second position. When actuator  108  is de-energized, that is, when the electrical current flowing through the coil is stopped or interrupted, the magnetic field around the coil dissipates and actuator plunger  110  is released causing interlocking arm  102  to move to the first position from the second position. 
     In some examples, a spring  112  is coiled around actuator plunger  110 . Spring  112  is provided to assist in movement of interlocking arm  102 . For example, spring  112  stores energy when actuator  108  draws actuator plunger  110  in and releases the stored energy when actuator  108  is de-energized. In some examples, the electrical current is provided to actuator  108  through input terminals  114 . In some examples, the electrical current for actuator  108  is provided from the electrical switch. In other examples, the electrical current for actuator  108  is provided from an external source. 
     Actuator  108  is housed within an actuator housing  116 . Actuator housing  116  is fixed or attached to an interlocking base  134 . In some examples, first end  104  of interlocking arm  102  includes an interlocking head  118 . A shape and size of interlocking head  118  is designed to form the releasable contact with switch operating mechanism  200  of switching device  220 . 
     Interlocking mechanism  100  further includes a status mechanism  120 . Status mechanism  120  can provide an indication of a current position of interlocking arm  102 . In some examples, status mechanism  120  provides an indication when interlocking arm  102  is disengaged from or retracted from the releasable contact with switch operating mechanism  200  rendering switching device  220  operable. The indication can be provided in form of an indication light although alternatives are possible. For example, the indication light turns green when interlocking arm  102  is disengaged or retracted from the releasable contact rendering switching device  220  operable and turns red when interlocking arm  102  is engaged with or positioned on the releasable contact rendering switching device  220  inoperable. In some examples, the indication is provided in form of sound or a signal. In other examples, the indication is provided in form of a text message or a voice message. 
     Status mechanism  120  includes a status arm  122 . A first end  124  of status arm  122  is connected to status mechanism  120  and a second end  126  of status arm  122  is located in a status notch  128  of interlocking arm  102 . Status notch  128  includes a first side  130  and a second side  132  opposite first side  130 . In some examples, status arm  122  is in contact with first side  130  of status notch  128  when interlocking arm  102  is in the second position and is in contact with second side  132  of status notch  124  when interlocking arm  102  is in the first position. Thus, status mechanism  120  provides the current position of interlocking arm  102  based on the current position of status arm  122 . In some other examples, status mechanism  120  can detect the current position of interlocking arm  102  by sensing an amount of current being consumed by or flowing through actuator  108 . For example, status mechanism  120  can detect that interlocking arm  102  is in the first position when the amount of current being consumed by or flowing through actuator  108  is approximately equal to zero and is in the second position when the amount of current being consumed by or flowing through actuator  108  is greater than zero. 
     In certain examples, actuator  108  is energized in response to receiving an actuator signal. The actuator signal is received over a wired network or a wireless network. In some examples, the actuator signal is received from a programmable circuit  136 . Programmable circuit  136  determines that a pre-determined condition for operating switching device  220  is met, generates, in response to determining that the pre-determined condition for operating switching device is  220  met, the actuator signal, and sends the actuator signal to actuator  108 . In response to receiving the actuator signal, actuator  108  is energized thereby allowing operation of switching device  220 . 
     In examples, the pre-determined condition may include checking that one or more loads are switched off. In another example, the pre-determined condition may include determining that a device or equipment that draws more than a predetermined amount of current is switched off. In yet another example, the pre-determined condition may include determining that exposed wires or exposed contacts are covered to sealed. 
     In some examples, actuator  108  is energized for a predetermined time period. In other examples, actuator  108  is energized until switching device  220  is operated, that is, switched on or switched off. Programmable circuit  136  can be remote from actuator  108  or can be co-located with actuator  108 . Programmable circuit  136  can be programmed to check one or more pre-determined conditions for operating the switch. In some examples, the one or more conditions can be dynamically changed. 
     In some examples, the actuator signal is received from a facility manager of a facility where switching device  220  to be operated is located. For example, the facility manager sends the actuator signal to actuator  108  over a wired network or a wireless network. In other examples, the actuator signal is received from a work site manager performing maintenance at the facility. 
     In certain examples, interlocking arm  102  is rotatable or movable around an arm axis  140 . Arm axis  140  is also referred to as an arm pivot or simply as pivot. An arm axis fastener  142  is used to control ease of rotation at arm axis  140 . For example, arm axis fastener  142  can be tightened and loosened to control the ease of rotation of interlocking arm  102 . An arm base fastener  144  is used for fastening interlocking arm  102  to interlocking base  118 . In examples, arm base fastener  144  is also used for controlling a degree of rotation or movement of interlocking arm  102 . For example, arm base fastener  144  is tightened or loosened to decrease or increase the degree of rotation or movement of interlocking arm  102 . 
     A plurality of actuator fasteners  146  are used for fastening actuator housing  116  to interlocking base  118 . A plurality of interlocking fasteners  148  are used for fastening interlocking base  118  or interlocking mechanism  100  to the cabinet of the electrical switch. Plurality of actuator fasteners  146  and plurality of interlocking fasteners  148  may include nuts, bolts, screws, studs, etc. 
     In examples, a length and a shape of interlocking arm  102  is configurable.  FIG.  3    illustrates another interlocking mechanism  100 ′ for switching device  220  in accordance with the principles of the present disclosure. Interlocking mechanism  100 ′ of  FIG.  3    includes another interlocking arm  102 ′. As shown in  FIG.  3   , a length L and a shape of interlocking arm  102 ′ of  FIG.  3    is different from a length and shape of interlocking arm  102  of  FIGS.  1  and  2   . For example, the length L and the shape of interlocking arm  102 ′ of  FIG.  3    is longer compared to the length of interlocking arm  102  in  FIGS.  1  and  2   . In examples, both interlocking mechanism  100  of  FIGS.  1 - 2    and another interlocking mechanism of  FIG.  3    works in a similar fashion. 
     In examples, the length and the shape of interlocking arm  102 , therefore, can depend upon an available space inside a cabinet, for example, enclosure  300  shown in  FIG.  7   , of switching device  220  for fastening interlocking mechanism  100 . In other examples, the length and the shape of interlocking arm  102  is can depend upon a voltage/current rating of switching device  220 . For example, a longer interlocking arm  102 ′ of  FIG.  3    is used for higher voltage/current ratings than interlocking arm  102  of  FIGS.  1  and  2   . 
       FIG.  4    illustrates interlocking mechanism  100  retracted from a releasable contact with switch operating mechanism  200  of switching device  220 . Switch operating mechanism  200  includes a switch control handle  202  (also referred to as a handle bar). Switch control handle  202  is pivoted at a handle pivot axis  204 . Switch control handle  202  is rotatable about an arc at handle pivot axis  204  between a first operating position and a second operating position. In depicted example, the first operating position can be a power-off position (also referred to as a power off configuration or a disconnect position) and the second operating position can be a power-on (also referred to as a power on configuration or a connect position). 
     Switch operating mechanism  200  further includes a crank member  206 . Crank member  206  is also pivoted at handle pivot axis  204  and is moveably connected to switch control handle  202 . For example, crank member  206  rotates or moves when switch control handle  202  is rotated or moved. In some examples, crank member  206  rotates in a same direction as switch control handle  202 . 
     Crank member  206  includes a contact slot  208 . In examples, contact slot  208  is a depression or an opening in a periphery of crank member  206 . A shape and size of contact slot  208  is designed to receive first end  104  (or interlocking head  118 ) of interlocking arm  102 . For example, the shape and size of releasable contact slot  208  is reciprocal to the shape and size of interlocking head  112  of interlocking arm  102 . In some examples, crank member  206  further includes a blocking member  210  adjacent to contact slot  208 . Blocking member  210  impedes rotation of crank member  206  when first end  104  of interlocking arm  102  is positioned in contact slot  208 . 
     In examples, interlocking arm  102  of interlocking mechanism  100  forms a releasable contact with switch operating mechanism  200 .  FIG.  5    illustrates interlocking mechanism  100  forming a releasable contact with switch operating mechanism  200  of switching device  220 . For example, and as shown in  FIG.  5   , when positioned in the first position, interlocking head  112  of interlocking arm  102  slides into contact slot  208  of crank member  206  forming a releasable contact with crank member  206  of switch operating mechanism  200 . When interlocking head  112  of interlocking arm  102  is positioned in contact slot  208 , it blocks rotation or movement of crank member  206  and, thus of switch control handle  202 , thereby not allowing operation of switch operating mechanism  200  of switching device  220 . On the contrary, and as shown in  FIG.  4   , when in the second position, interlocking head  112  of interlocking arm  102  is retracted from contact slot  208  of crank member  206 . When interlocking head  112  is retracted from contact slot  208 , it allows rotation or movement of crank member  206  and switch control handle  202  thereby allowing operation of switch operating mechanism  200  or switching device  220 . 
     Switch operating mechanism  200  further includes a plurality of door prongs  212 . Plurality of door prongs  212  form a door safety mechanism that does not allow door  306  of cabinet  300  that includes switching device  220  to open when switch control handle  202  is in the second position (that is, the power on configuration). In some examples, plurality of door prongs  212  are configured to not allow rotation or movement of switch control handle  202  to the operating second position (that is, the power on configuration) when door  306  of cabinet  300  is in the open position. In some other examples, plurality of door prongs  212  are configured to not allow opening of door  306  of cabinet  300  when switch control handle  202  is at the operating second position. 
     As shown in  FIGS.  6 A and  6 B , plurality of door prongs  212  include a first door prong  212   a  and a second door prong  212   b.  First door prong  212   a  is connected to second door prong by a door spring member  230 . First door prong  212   a  engages with a prong hook  228  of crank member  206 . For example, when door  306  is open, first door prong  212   a  engages with prong hook  228  (see  FIG.  6 A ) thereby inhibiting rotation of crank member  206 , and by extension, of switch control handle  202  to the second operating position. Thus, plurality of door prongs  212  block switching on switching device  220  when door  306  of cabinet  300  is open. When door  306  is in closed position and switch control handle  202  is at the second operating position, a hook portion of second door prong  212   b  engages with a door safety hook  226  located on a door  306  of cabinet  300  of switching device  220  (see  FIG.  6 B ) thereby blocking operation of door  306 . 
     Returning to  FIG.  5   , switch operating mechanism  200  further includes a plurality of fasteners  218  to fasten or couple switch operating mechanism  200  to cabinet  300 . Switch operating mechanism  200  further includes a link member  214  and a support shaft  216 . Link member  214  is connected to both crank member  206  and support shaft  216 . For example, a first end of link member  214  is connected to crank member  206  and a second end of link member  214  is connected to a first end of support shaft  216 . In certain examples, link member  214  and support shaft  216  help in operation of switch operating mechanism  200 . For example, link member  214  and support shaft  216  provide supporting movement in shifting or moving switch control handle  202  between the first operating position and the second operating position. 
       FIG.  7    illustrates switching device  220  and switching units  224  of switching device  220 . For example, and as shown in  FIG.  7   , switching device  220  can include a plurality of switching units  224 , for example, a first switching unit  224   a,  a second switching unit  224   b,  and a third switching unit  224   c.  Although, switching device  220  of  FIG.  6    is shown to include three switching units, it can include a different number of switching units (for example, one, two, four, five, etc.). 
     In some examples, each of plurality of switching units  224  include an assembly of electrical contacts that are switchable or shiftable between an open configuration (or an open condition) and a closed configuration (or closed condition). The assembly of electrical contacts are connected to an actuator shaft  222  that shifts the electrical contacts between their open and closed configurations. For example, actuator shaft  222  is connected to crank member  206  at handle pivot axis  204  and is moveably connected to switch control handle  202 . For example, actuator shaft  222  rotates or moves when switch control handle  202  is rotated or moved between the first position and the second position. In some examples, actuator shaft  222  rotates in a same direction as switch control handle  202 . Hence, when switch control handle  202  is rotated to the off position (that is, the first position), actuator shaft  222  shifts the electrical contacts to the open configuration, and when switch control handle  202  is rotated to the on position (that is the second position), actuator shaft  222  shifts the electrical contacts to the closed configuration. In some examples, at any given time, each of plurality of switching units  224  have a same configuration, either open or closed. In the open configuration, no current flows through the plurality of switching unites while in the closed configuration electric current flows through the plurality of switching unites. 
       FIG.  8    illustrates an example cabinet  300  of switching device  220 . In some examples, cabinet  300 , also referred to as an enclosure  300 , includes a back wall  302  and a plurality of side walls, that is, a first side wall  304   a,  a second side wall  304   b,  a third side wall  304   c,  and a fourth side wall  304   d.  In addition, enclosure  300  includes door  306 . Door  306  can be hinged on one of the sidewalls, for example, third side wall  304   c,  using one or more hinges  308  and can swing freely on hinges  308 . 
     Continuing with  FIG.  8   , elements of switching device  220  including interlocking mechanism  100  and switch operating mechanism  200  are mounted inside cabinet  300 . For example, and as shown in  FIG.  8   , interlocking mechanism  100  and switch operating mechanism  200  are mounted on back wall  302  and closer to first side wall  304   a  of cabinet  300 . Switch control handle  202  is located outside of first side  304   a  for cabinet  300 . In certain examples, although shown mounted closer to first side wall  304   a,  interlocking mechanism  100  and switch operating mechanism  200  can be mounted closer to any of first side wall  304   a , second side wall  304   b,  third side wall  304   c,  and fourth side wall  304   d.    
       FIG.  9    illustrate an example defeat or override mechanism  400  for interlocking mechanism  100 . Defeat mechanism  400  allows a user or an authorized user to defeat and operate electrical switch irrespective of whether an actuator signal has been received or not. As shown in  FIG.  8   , defeat mechanism  400  includes an override actuator  402 . Defeat mechanism  400  further includes an override arm  404  and an override spring  406 . A first end of override actuator  402  is located in a socket head  408  with a recess  410  shaped to receive a tool, for example, a screwdriver. In certain examples, the tool and socket head  408  can have a unique shape so as to provide a key function that allows only authorized personal to operate defeat mechanism  400 . A second end of override actuator  402  is connected to override arm  404 . Override spring  406  is also connected to override arm  404 . Override arm  406  is in contact with second end  106  of interlocking arm  102  of interlocking mechanism  100 . 
     In some examples, override actuator  402  is located outside of cabinet  300  and can be rotated to activate override mechanism  400 . In some other examples, override actuator  402  is located inside of cabinet  300  and is accessible through a hole in cabinet  300 . Override actuator  402  is rotated to adjust position of override arm  404  against bias of override spring  406 . For example, when override actuator  402  is rotated, override arm  404  rotates in a same direction of override actuator  402  thereby moving interlocking arm  102  of interlocking mechanism  100  from the first position to the second position. Hence, when override actuator  402  is rotated, interlocking arm  102  retracts from the releasable contact with switch operating mechanism  200  thus defeating interlocking mechanism  100  and allowing operation of switching device  220 . 
       FIG.  10    illustrates a flow diagram of a method  500  for operating switching device  220 . At block  510  of method  500 , it is determined that a pre-determined condition for operating switching device  220  is met. In certain examples, programmable circuit  136  determines that pre-determined condition for operating switching device  220  is met. In examples, programmable circuit  136  compares the predetermined conditions with one or more current conditions to determine that pre-determined condition for operating switching device  220  is met. For example, programmable circuit  136  can determine that one or more loads are switched off. In another example, programmable circuit  136  can determine that a device or equipment that draws more than a predetermined amount of current is switched off. In yet another example, programmable circuit  136  can determine that exposed wires or exposed contacts are covered to sealed. 
     At block  520  of method  500 , an actuator signal is generated in response to determining that the pre-determined condition for operating switching device  220  is met. For example, programmable circuit  136  generates an actuator signal in response to determining that a pre-determined condition for operating switching device  220  is met. 
     At block  530  of method  500 , the actuator signal is sent to actuator  108  connected to interlocking arm  102  of an interlocking mechanism  100 . For example, programmable circuit  136  sends the actuator signal to actuator  108 . Actuator  108 , in response to receiving the actuator signal, moves interlocking arm  102  from a first position to a second position. Interlocking arm  102  includes first end  104  and second end  106 . When positioned in the first position, first end  104  of interlocking arm  102  forms a releasable contact with switch operating mechanism  200  of switching device  220  blocking operation of switching device  220 . When positioned in the second position, first end  104  of interlocking arm  102  withdraws from the releasable contact with switch operating mechanism  200  of switching device  220  allowing operation of switching device  220 . 
     Various modifications and alternations of this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure, and it should be understood that the inventive scope of this disclosure is not to be unduly limited to the illustrative embodiments set forth therein.