Abstract:
An openable cover for an enclosure configured to house a switching device, the switching device being configured with an operating member operable between a first position and a second position. The openable cover comprises a moveable member operable in response to movement of the operating member. The movable member is configured to prevent opening of the cover member when the operating member is in the first position, and configured to prevent closing of the cover member when the operating member is in the second position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The field of the present invention relates to an enclosure for an electrical device generally, and more particularly to an interlockable enclosure cover for a switch, such as a circuit breaker, of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same. 
     2. Description of the Related Art 
     In conventional electrical distribution and control systems, electrical switching devices such as circuit breakers for switching power ON and OFF are often enclosed in an housing having an openable cover. Such housings are typically of metallic or polymeric material and include a hinged door or removeable cover providing access to the interior of the housing. Non-limiting examples of conventional electrical device housings include switch enclosures, busway “busplugs”, motor control centers, panelboards, and switchgear. 
     In  FIGS. 1A and 1B , a conventional switch device enclosure  100  is shown, having a switching device, such as a circuit breaker or switch  101  having an operating member  103  for switching power installed therein. A hinged cover or door  104  is openable via hinges  133   a ,  133   b  to provide access to the interior of enclosure  100 . The door  104  is retained in a closed position by fasteners such as screws (not shown) and/or any number of releasable door-latching mechanisms having a biased releasable latch member  108  arranged to protrude through an aperture  110  in the door  104 . Such latch members  108  are provided with an aperture  112  configured to receive a locking member (not shown) such as the hasp of a lock (not shown) for locking the cover  104  closed. 
     When closed, the door  104  prevents direct operative access to the operating member  103  of the enclosed switch  101 . Operating handle  102  mounted external to the enclosure  100  and movable in the directions indicated by arrow  119  is configured to drive a mechanism including, for example, a moveable yoke  105 , which in turn drives the operating member  103  of switch  101  for toggling the switch  101  from a power ON position to a power OFF position. Labels (not shown) having text such as “ON” and “OFF”, are positioned on enclosure  100  to correspond to operating handle  102  positions that likewise correspond to, and thus indicate, the state of the enclosed switch  101 . 
     Various electrical standards require, as a safety feature, an interlock or latch mechanism to prevent opening of the door or removal of the cover while the enclosed switch is in the ON or conducting state. Prior art interlock assemblies  141  are conventionally configured to cooperate with a mechanism  142  driven by the externally-mounted operating handle  102  to prevent the opening of the door  104  while the enclosed switch  101  is in the ON or conducting state. 
     While safety latch assemblies for enclosures are generally known in the art, they have certain disadvantages. They are generally complex and expensive, often with a relatively large number of parts, and some permit closing of the cover  104  with the enclosed switch  101  in the ON position. This latter disadvantage can result in the enclosed switch  101  being in an ON or conducting state while the external operating member  102  position incorrectly indicates that the enclosed switch  101  is in an OFF or non-conducting state, thus resulting in a potentially hazardous condition. 
     It is desirable to provide an improved device configured to allow direct external operability of a switch or circuit interrupter installed in a housing, with a simpler, low cost apparatus to prevent opening and/or closing of the enclosure cover when the enclosed switch is in the “ON” position. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the foregoing considerations, it is desirable to provide a device to provide an enclosure having a safety latch assembly that is relatively simple in construction, using a minimum number of parts that prohibits closing of the enclosure cover with the enclosed switch in the ON position, and preferably prevents both closing and opening of the enclosure cover with the enclosed switch in the ON position. 
     In an embodiment, an enclosure for a switching device having an operating member operable between a first ON and a second OFF position is provided. The enclosure comprises a simple latch assembly that is configured to move in response to the operation of the enclosed switching device operating member to prevent opening of the enclosure when the enclosed switch  101  is in the first ON position. 
     In another embodiment, an openable cover for an enclosure configured to house a switching device configured with an operating member operable between a first ON and a second OFF position, is provided. The openable cover comprises a moveable member operable in response to movement of the switching device operating member and is configured to prevent opening of the cover member when the operating member is in the first ON position. 
     Other features and advantages of the disclosure will become apparent by reference to the following description taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as one or more of the features of any drawing may be combined with any or all of the other features of one or more of the remaining drawings in accordance with one or more embodiments of the invention. 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate a presently preferred embodiment of the invention, in which: 
         FIG. 1A  illustrates a top view of a prior art switch housing having an interlock mechanism; 
         FIG. 1B  illustrates a side view, with partial cut-away, of the prior art switch housing of  FIG. 1A ; 
         FIG. 2  is an exploded view illustrating an embodiment of the present invention; 
         FIG. 3  is a side view with partial cutaway of an embodiment of a cover of the present invention; 
         FIG. 4  is a top view of an embodiment of an interlock member of the present invention; and 
         FIG. 5  is a cross-section end view of the embodiment of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As used herein, an element or function recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or functions, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the claimed invention should not be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views. 
     In  FIG. 2 , a housing  200  configured to enclose a conventional switching device  101 , such as a circuit breaker or switch having an operating member  103  for toggling the switch  101  from a power ON position to a power OFF position installed therein is shown. A cover or door  204  having a first interior surface  256  ( FIG. 3 ) and a second exterior surface  266  is openable to provide access to the interior of the housing  200 . The cover  204  is provided with a first aperture  211 , configured to allow the installed switch  101  operating member  103  to protrude therethrough when the cover  204  is closed. The first aperture  211  is dimensioned to allow operating member  103  to travel through its full operable range of motion to allow operation of the switch  101 . 
     The door  204  may be retained in a closed position by fasteners such as screws  206   a ,  206   b  and/or any number of releasable door-latching mechanisms having a latch member  208  arranged to protrude through a second aperture  212   a  in the door  204 . Latch member  208  is provided with an aperture  212   b  configured to receive a locking member (not shown) such as the hasp of a lock (not shown) for locking the cover  204  closed. It is contemplated that in some embodiments, the door  204  may be hingeably attached to the enclosure  200 , such as, for example, with hinges  233   a ,  233   b  cooperating with apertures  234   a ,  234   b.    
     An interlock member  225  having a top surface  226   a  and a bottom surface  226   b  ( FIG. 3 ) is movably connected to the first interior surface  256  of door  204  and configured to move in response to movement of a switching device operating member  103  installed in the housing  200 . Preferably, cover  204  is configured such that when the cover  204  is closed, the interlock member  225  is not accessible from the exterior of housing  200 . For example, door  204  may additionally comprise at least one flange  214  formed generally orthogonal to top surface  226   a  and configured to cooperate with enclosure  200  to prevent access to interlock member when door  204  is closed. 
     In an embodiment, interlock member  225  is provided with a third notch, opening, or aperture  223 , positioned to allow the switch  101  operating member  103  to protrude therethrough when the cover  204  is closed. Interlock member  225  aperture  223  and cover  204  aperture  211  are configured to cooperate to allow the installed switch  101  operating handle  103  to protrude external to the housing  200  and to allow direct operation of the switch  101  operating handle  103 . In order to allow operation of switch  101  when the cover  204  is closed, the interlock member  225  aperture  223  is configured such that movement of the switch operating member  103  causes movement of the interlock member  225 . 
     It is contemplated that the movable connection of interlock member  225  to door  204  may be accomplished through a variety of ways. For example, in one embodiment, two fasteners or shouldered rivets  230 ,  231  connect interlock member  225  to the first interior surface  256  door  204 . Two or more generally parallel slots  227 ,  228  are disposed in interlock member  225  and are configured to slidably capture respective shouldered rivets  230 ,  231 . A first end of each of the rivets  230 ,  231  are fixedly attached to door  204  via peening or other known methods. A second end of the at least two rivets  230 ,  231  are disposed through respective slots  227 ,  228  in interlock member  225 . 
       FIG. 5  illustrates a cross-section end view of the embodiment of  FIG. 3  looking in the direction of A-A of  FIG. 3 . In an embodiment, two generally U-shaped brackets  290 ,  291  are attached via known methods, such as welding, to the first interior surface  256  of door  204  and disposed to slidably support interlock member  225  adjacent the first interior surface  256  of door  204 . 
     Referring again to  FIG. 2 , an interlock formation  260  is provided on housing  200  and oriented to latchably engage a corresponding latching portion  229  of interlock member  225  to prevent opening of door  204  when the enclosed switch  101  operating member  103  is in the ON position. Conversely, interlock formation  260  is further arranged such that, when the enclosed switch  101  operating member  103  is in the OFF position, the corresponding latching portion  229  of interlock member  225  is not latchably engaged by the interlock formation  260 . 
     It is contemplated that the interlock formation  260  may embody a variety of forms to accommodate a latching function in cooperation with the corresponding latching portion  229  of interlock member  225 . In one exemplary embodiment, and as shown in  FIG. 2 , a portion of housing  200  is configured in the form of a tab  260  oriented to latchably engage the corresponding latching portion  229  of interlock member  225  when the enclosed switch  101  operating member  103  is in the ON position and door  204  is closed. When the enclosed switch  101  operating member  103  is moved to the OFF position, the corresponding latching portion  229  of interlock member  225  is released, or unlatched, from the interlock formation  260 , and the door  204  may be opened. Additionally, interlock formation  260  is disposed to cooperate with latching portion  229  of interlock member  225  to prevent closure of door  204  when door  204  is open and the enclosed switch  101  operating member  103  is in the ON position. 
     Referring to  FIG. 2  and  FIG. 3 , interlock member  225  may additionally be configured with a first locking tab  254  configured to cooperate with a corresponding second locking tab  264  disposed on door  204 . First locking tab  254 , and second locking tab  264  are formed generally orthogonal to top surface  226   a  of door  200 . First locking tab  254  is configured with a first aperture  254   a , and second locking tab  264  is configured with a second aperture  264   a . First aperture  254   a , and second aperture  264   a  are disposed to receive a locking member (not shown) such as the hasp of a lock (not shown) for locking the enclosed switch  101  operating member  103  in the OFF position when door  200  is closed. 
     With respect to the above description, it should be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, form function and manner of operation, assembly and use, are deemed readily apparent and illustrated in the drawings and described in the specification are intended to be encompassed only by the scope of appended claims. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention 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 claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.