Patent Publication Number: US-9905387-B2

Title: Circuit breaker including end covers

Description:
BACKGROUND 
     The field of the disclosure relates generally to circuit breakers and, more particularly, to circuit breakers including end covers. 
     Circuit breakers are often used to protect, in a residential, industrial, utility, or commercial environment, against overcurrent conditions, ground fault conditions, or other system anomalies that are undesirable and require the circuit breaker to interrupt the flow of current through the circuit breaker. At least some known circuit breakers include lugs for coupling to a circuit. For example, in some circuit breakers, a load lug is positioned on an end of the circuit breaker and a line lug is positioned on an opposite end of the circuit breaker. Current flows through the circuit breaker from the line lug to the load lug. When the circuit breaker has a reverse feed, the current flows through the circuit breaker from the load lug to the line lug. Sometimes, operation of the circuit breaker generates arc gases and particulates which cause deterioration of components of the circuit breaker. Accordingly, some circuit breakers include shielding to inhibit the arc gases and particulates from contacting components such as the line lugs. 
     At least some known circuit breakers include an electrically insulative case and end covers coupled to the ends of the electrically insulative case. Typically, a different end cover is required for coupling to each end of the electrically insulative case. For example, the end cover adjacent the line lugs is differentiated from the end cover adjacent the load lug to accommodate shielding that inhibits arc gas and particulates from contacting the line lugs. Moreover, each end cover is assembled from multiple unique parts which increase the number of parts required to assemble the circuit breakers. Also, some circuit breakers are assembled without lugs on at least one end. Accordingly, a different end cover, e.g., a finishing cover, is coupled to the electrically insulative case adjacent the end without lugs. As a result, the cost to manufacture and assemble circuit breakers including end covers is increased. 
     BRIEF DESCRIPTION 
     In one aspect, a circuit breaker is provided. The circuit breaker includes an electrically insulative case including a first end and a second end opposite the first end. The circuit breaker further includes an end cover selectively installable on both the first and second ends of the electrically insulative case. The end cover includes a wall defining at least one opening for receiving a removable shield, a first end connectable to the electrically insulative case first end, and a second end connectable to the electrically insulative case second end. 
     In another aspect, an end cover for a circuit breaker having an electrically insulative case is provided. The end cover is selectively installable on both a first end and a second end of the electrically insulative case. The end cover includes a first end and a second end opposite the first end. The first end of the end cover is connectable to the first end of the electrically insulative case and the second end of the end cover is connectable to the second end of the electrically insulative case. The end cover further includes a wall defining an interior space sized to receive at least one lug extending from the electrically insulative case. 
     In yet another aspect, a method of manufacturing a circuit breaker is provided. The method includes positioning a lug adjacent to an end of an electrically insulative case and coupling an end cover to the end of the electrically insulative case adjacent the lug. The end cover includes a wall defining at least one opening sized to receive at least one removable shield. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a perspective view of a circuit breaker; 
         FIG. 2  is a schematic view of the circuit breaker shown in  FIG. 1 ; 
         FIG. 3  is a sectional view of a portion of the circuit breaker shown in  FIG. 1 ; 
         FIG. 4  is a perspective front view of an end cover of the circuit breaker shown in  FIG. 1 ; 
         FIG. 5  is a perspective rear view of the end cover shown in  FIG. 4 ; 
         FIG. 6  is a top view of the end cover shown in  FIG. 4 ; 
         FIG. 7  is a perspective view of a removable shield of the end cover shown in  FIG. 4 ; 
         FIG. 8  is a side view of the removable shield shown in  FIG. 7 ; 
         FIG. 9  is a front view of the removable shield shown in  FIG. 8 ; 
         FIG. 10  is a perspective view of a portion of an end cover of the circuit breaker shown in  FIG. 2 ; 
         FIG. 11  is a side view of a plug of the end cover shown in  FIG. 10 ; 
         FIG. 12  is a top view of an alternative end cover for the circuit breaker shown in  FIG. 1 ; and 
         FIG. 13  is a perspective view of a portion of the end cover shown in  FIG. 12 . 
     
    
    
     Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems including one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein. 
     DETAILED DESCRIPTION 
     In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. 
     The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. 
     “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. 
     Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “substantially,” and “approximately,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. 
     Exemplary embodiments of circuit breakers and methods of manufacturing circuit breakers are described herein. The circuit breakers generally include an electrically insulative case and end covers coupled to line and load ends of the case. The end covers are interchangeable to reduce the number of unique parts required to manufacture and assemble circuit breakers. A removable shield couples to the end cover coupled to the line end to shield line lugs from arc gas and particulates during operation of the circuit breakers. A plug couples to the end cover coupled to the load end to close an opening for receiving the removable shield. In some embodiments, a finishing end cover is coupled to an end of the case when lugs are omitted from the respective end of the circuit breaker. 
       FIG. 1  is a perspective view of a circuit breaker  100 . Circuit breaker  100  includes a case  102  and an operating mechanism  104 . In alternative embodiments, circuit breaker  100  includes any components that enable circuit breaker  100  to operate as described herein. For example, in some embodiments, circuit breaker  100  includes load straps, movable contacts, and/or trip mechanisms. In the exemplary embodiment, circuit breaker  100  is coupled to a circuit such that circuit breaker  100  controls flow of electric current through the circuit. In particular, when operating mechanism  104  of circuit breaker  100  is triggered, i.e., circuit breaker  100  is tripped, the flow of electric current through the circuit coupled to circuit breaker  100  is stopped. 
       FIG. 2  is a schematic view of circuit breaker  100 . Circuit breaker  100  further includes line lugs  112  and load lugs  114 . A power source  116  is connected to line lugs  112  and a load  118  is connected to load lugs  114  such that current flows through circuit breaker  100  from line lugs  112  to load lugs  114 . In alternative embodiments, power source  116  is connected to load lugs  114  and load  118  is connected to line lugs  112  such that current flows through circuit breaker  100  from load lugs  114  to line lugs  112 . In the exemplary embodiment, circuit breaker  100  includes three line lugs  112  and three load lugs  114 . In alternative embodiments, circuit breaker  100  includes any line lugs  112  and load lugs  114  that enable circuit breaker  100  to operate as described herein. For example, in some embodiments, line lugs  112  and/or load lugs  114  are omitted. 
     In reference to  FIGS. 1 and 2 , case  102  is configured to electrically insulate circuit breaker  100  such that electrical current is inhibited from passing through case  102  to the surrounding environment. Case  102  includes a first end  120  and a second end  122  opposite first end  120 . First end  120  and second end  122  are at least partially open to provide access to circuit breaker  100 . Line lug  112  is adjacent first end  120  such that power source  116  is coupled to circuit breaker  100  adjacent first end  120 . Accordingly, first end  120  forms a line end of circuit breaker  100 . Load lug  114  is adjacent second end  122  such that load  118  is coupled to circuit breaker  100  adjacent second end  122 . Accordingly, second end  122  forms a load end of circuit breaker  100 . In alternative embodiments, case  102  has any configuration that enables circuit breaker  100  to operate as described herein. 
     In the exemplary embodiment, circuit breaker  100  further includes first end cover  124  and second end cover  126 . First end cover  124  is coupled to first end  120  adjacent line lugs  112 . Second end cover  126  is coupled to second end  122  adjacent load lugs  114 . First end cover  124  and second end cover  126  receive line lugs  112  and load lugs  114  and are configured to electrically insulate line lugs  112  and load lugs  114  and to inhibit objects from contacting line lugs  112  and load lugs  114 . Moreover, first end cover  124  and second end cover  126  protect line lugs  112  and load lugs  114  from the environment to inhibit deterioration of line lugs  112  and load lugs  114 . First end cover  124  and second end cover  126  are interchangeable. In other words, first end cover  124  is configured to couple to second end  122  and second end cover  126  is configured to couple to first end  120 . In alternative embodiments, first end cover  124  and second end cover  126  have any configurations that enable circuit breaker  100  to operate as described herein. 
       FIG. 3  is a sectional view of a portion of circuit breaker  100  including first end cover  124 .  FIG. 4  is a perspective front view of first end cover  124 .  FIG. 5  is a perspective rear view of first end cover  124 .  FIG. 6  is a top view of first end cover  124 . First end cover  124  includes a top wall  128 , a bottom wall  130 , and a pair of sidewalls  132  extending between top wall  128  and bottom wall  130 . Together, top wall  128 , bottom wall  130 , and sidewalls  132  define an interior space  134  for receiving line lugs  112 . A removable shield  136  is coupled to first end cover  124  and extends in interior space  134  adjacent line lug  112 . Top wall  128  defines an opening  138  for receiving a portion of removable shield  136 . In alternative embodiments, first end cover  124  has any walls that enable first end cover  124  to function as described herein. 
     In the exemplary embodiment, removable shield  136  inhibits arc gas  140  and particulates from contacting line lugs  112  during operation of circuit breaker  100 . As will be described below, removable shield  136  engages top wall  128 . To install removable shield  136 , removable shield  136  is inserted in opening  138  until a snap fit is achieved. When removable shield  136  is fully inserted in opening  138 , a top surface  137  of removable shield  136  is substantially flush with a top surface  139  of top wall  128 . In alternative embodiments, removable shield  136  is coupled to first end cover  124  in any manner that enables circuit breaker  100  to operate as described herein. 
     Also, in the exemplary embodiment, first end cover  124  further includes an upper portion  142  and a lower portion  144 . Upper portion  142  includes top wall  128  and portions of side walls  132 . Lower portion  144  includes bottom wall  130  and portions of side walls  132 . Upper portion  142  and lower portion  144  are removably coupled together and at least partially define interior space  134 . A plurality of partitions  150  extend between top wall  128  and bottom wall  130  and divide interior space  134  into a plurality of slots  152  for receiving line lugs  112 . Each slot  152  corresponds with one opening  138  in top wall  128 . Accordingly, removable shields  136  extend in slots  152  adjacent line lugs  112  when coupled to upper portion  142 . In the illustrated embodiment, interior space is divided into three slots  152 . In alternative embodiments, interior space  134  is divided into any slots  152  that enable circuit breaker  100  to operate as described herein. 
     In reference to  FIGS. 1, 4, and 5 , first end cover  124  is reversible such that a first end  146  couples to first end  120  of case  102  and an opposite second end  148  couples to second end  122  of case  102 . In particular, first end  146  of first end cover  124  includes a plurality of first engagement components  154  to engage first end  120  of case  102 . Second end  148  of first end cover  124  includes a plurality of second engagement components  156  to engage second end  122  of case  102 . Moreover, first engagement components  154  and second engagement components  156  are differentiated to inhibit coupling first end cover  124  to case  102  in the incorrect orientation. For example, first engagement components  154  are configured to engage first end  120  but not second end  122 . 
     First engagement components  154  and second engagement components  156  each include a keyed projection having a shape that corresponds to a channel  157  on first end  120  or second end  122 . To couple first end cover  124  to case  102 , first engagement components  154  or second engagement components  156  are inserted at partially in the corresponding channels  157  on first end  120  or second end  122 . Upper portion  142  is removably coupled to lower portion  144  to secure first engagement component  154  or second engagement component  156  in the corresponding channel. First engagement components  154  and second engagement components  156  are omitted on lower portion  144  such that lower portion  144  couples to case  102  in either direction. In alternative embodiments, first end cover  124  has any engagement components  154 ,  156  that enable circuit breaker  100  to operate as described herein. In some embodiments, at least one of first engagement component  154  and second engagement component  156  is adjustable to facilitate coupling first end cover  12  to different circuit breakers  100 . For example, in some embodiments, first engagement components  154  include knockouts configured to facilitate coupling first end cover  124  to draw-out units. 
       FIG. 7  is a perspective view of removable shield  136 .  FIG. 8  is a side view of removable shield  136 .  FIG. 9  is a front view of removable shield  136 . Removable shield  136  includes an engagement portion  158 , a deflection portion  160 , and a perforated portion  162  extending between engagement portion  158  and deflection portion  160 . Deflection portion  160  is angled in relation to perforated portion  162  such that deflection portion  160  and perforated portion  162  form an angle  163 . During operation of circuit breaker  100 , arc gas  140  contacts deflection portion  160  and is directed along deflection portion  160  away from line lugs  112  (shown in  FIG. 3 ). A portion of arc gas  140  is directed towards perforated portion  162  and flows through openings in perforated portion  162  for exhausting from case  102  (shown in  FIG. 1 ). Perforated portion  162  is positioned above line lugs  112  (shown in  FIG. 3 ) such that arc gas  140  flows away from line lugs  112  and is inhibited from contacting line lugs  112 . In alternative embodiments, circuit breaker  100  includes any removable shields  136  that enable circuit breaker  100  to operate as described herein. 
     In reference to  FIGS. 3 and 8 , engagement portion  158  of removable shield  136  includes engagement components  164  to engage top wall  128 . Engagement components  164  include a plurality of ridges  166  and a lip  168 . Ridges  166  deform as removable shield  136  is inserted through opening  138  and return to shape after passing through opening  138 . As a result, engagement components  164  facilitate a snap-fit engagement between removable shield  136  and top wall  128  to inhibit displacement of removable shield  136  from opening  138 . Lip  168  facilitates alignment of removable shield  136  in opening  138 . In addition, lip  168  includes a tab  170  to facilitate removal of removable shield  136  from first end cover  124 . To remove removable shield  136  from first end cover  124 , a user applies force to a portion of removable shield  136 , such as tab  170 , until ridges  166  deform and allow release of engagement portion  158  from opening  138 . Removable shield  136  is then pulled through opening  138  until removable shield  136  is free of first end cover  124 . In alternative embodiments, removable shield  136  has any engagement portion  158  that enables removable shield  136  to function as described herein. 
       FIG. 10  is a perspective view of upper portion  142  of second end cover  126 .  FIG. 11  is a side view of a plug  172  of second end cover  126 . Upper portion  142  removably couples to lower portion  144  (shown in  FIG. 3 ) and includes top wall  128  defining openings  138 . Second end cover  126  further includes sidewalls  132  and partitions  150  at least partly defining slots  152  for receiving line lugs  112  and load lugs  114 . In the illustrated embodiment, second end cover  126  is configured for coupling to second end  122  adjacent load lugs  114 . Accordingly, removable shields  136  (shown in  FIG. 3 ) are omitted since shielding of load lugs  114  is unnecessary. To inhibit access through openings  138 , plugs  172  are installed in openings  138 . In alternative embodiments, second end cover  126  is configured in any manner that enables circuit breaker  100  to operate as described herein. For example, in some embodiments, second end cover  126  is coupled to first end  120  of case  102 . In further embodiments, at least one removable shield  136  (shown in  FIG. 3 ) is coupled to second end cover  126 . 
     In the exemplary embodiment, plugs  172  are positioned in openings  138  such that a top surface  174  of each plug  172  is substantially flush with top surface  139  of second end cover  126 . Each plug  172  includes engagement components  176  that engage top wall  128  when plug  172  is inserted in opening  138 . Engagement components  176  include a plurality of ridges  178  and a lip  180 . Ridges  178  deform as plug  172  is inserted through opening  138  and return to shape after passing through opening  138 . As a result, engagement components  176  facilitate a snap-fit engagement between plug  172  and top wall  128  to inhibit displacement of plug  172  from opening  138 . Lip  180  facilitates alignment of removable shield  136  in opening  138 . In addition, lip  180  includes a tab  182  to facilitate removal of plug  172  from second end cover  126 . To remove plug  172  from second end cover  126 , a user applies force to a portion of plug  172 , such as tab  182 , until ridges  178  deform and allow release of plug  172  from opening  138 . In some embodiments, plugs  172  are positioned in at least one opening  138  of first end cover  124 . In alternative embodiments, circuit breaker  100  includes any plugs  172  that enable circuit breaker  100  to operate as described herein. 
       FIG. 12  is a top view of an alternative end cover  200  for circuit breaker  100 .  FIG. 13  is a perspective view of an upper portion  202  of end cover  200 . Upper portion  202  removably couples to a lower portion  204  to form end cover  200 . End cover  200  is configured for use with circuit breaker  100  (shown in  FIG. 1 ) when line lugs  112  (shown in  FIG. 1 ) and/or load lugs  114  (shown in  FIG. 1 ) are omitted. In other words, end cover  200  acts as a finishing end cover for use when at least one end of circuit breaker  100  (shown in  FIG. 1 ) is coupled directly to a circuit without a lug. End cover  200  further includes a first end  206 , a second end  208 , a top wall  210 , a pair of sidewalls  212 , and a plurality of partitions  214 . Top wall  210  and sidewalls  212  at least partially define an interior space  216 . Partitions  214  divide interior space  216  into a plurality of slots  218 . First end  206  couples to first end  120  (shown in  FIG. 1 ) of case  102  (shown in  FIG. 1 ) and second end  208  couples to second end  122  (shown in  FIG. 1 ) of case  102  (shown in  FIG. 1 ). Accordingly, end cover  200  is reversible such that different end covers  200  are not required for different ends of case  102  (shown in  FIG. 1 ). In alternative embodiments, end cover  200  has any configuration that enables circuit breaker  100  to operate as described herein. 
     In reference to  FIGS. 1, 2, 3, and 10 , a method of manufacturing circuit breaker  100  includes positioning line lug  112  adjacent first end  120  of case  102 . In some embodiments, load lug  114  is positioned adjacent second end  122  of case  102 . The method further includes coupling first end cover  124  to first end  120  adjacent line lug  112 . In some embodiments, second end cover  126  is coupled to second end  122  adjacent load lug  114 . In further embodiments, removable shield  136  is coupled to first end cover  124  and plug  172  is positioned in opening  138  to close opening  138 . 
     The circuit breakers described above generally include an electrically insulative case and end covers coupled to line and load ends of the case. The end covers are interchangeable to reduce the number of unique parts required to manufacture and assemble circuit breakers. A removable shield couples to the end cover coupled to the line end to shield line lugs from arc gas and particulates during operation of the circuit breakers. A plug couples to the end cover coupled to the load end to close an opening for receiving the removable shield. In some embodiments, a finishing end cover is coupled to an end of the case when lugs are omitted from the respective end of the circuit breaker. 
     An exemplary technical effect of the methods, systems, and apparatus described herein includes at least one of: (a) reducing cost to assemble circuit breakers; (b) providing interchangeable end covers for circuit breakers; (c) reducing the number of unique parts required for circuit breakers; and (d) increasing the lifecycle of lugs. 
     Exemplary embodiments of circuit breakers and methods of manufacturing circuit breakers are described above in detail. The circuit breakers and methods are not limited to the specific embodiments described herein but, rather, components of the circuit breakers and/or operations of the methods may be utilized independently and separately from other components and/or operations described herein. Further, the described components and/or operations may also be defined in, or used in combination with, other systems, methods, and/or devices, and are not limited to practice with only the circuit beakers and systems described herein. 
     The order of execution or performance of the operations in the embodiments of the disclosure illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments of the disclosure may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the disclosure. 
     Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.