Abstract:
An improved frame for a switchgear cabinet includes a plurality of rails that are connected together with a plurality of connectors. The rails are generally of two different cross-sectional configurations, both of which are cooperable with a single type of connector to enable the rails and connectors to be configured into numerous different types of cabinet frames to which panels can be mounted to form switchgear cabinets. The rails and connectors are modular in nature and are specifically configured to be easily connected with one another. During assembly of the connectors and the rails, portions of a coating on the rails become ruptured, thereby electrically conductively connecting together the rails and the connectors.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to power distribution equipment and, more particularly, to a modular frame of a cabinet within which power distribution equipment can be disposed. 
     2. Description of the Related Art 
     As is known in the relevant art, power distribution equipment typically includes circuit breakers and other associated switchgear. In use, such equipment typically is mounted within a switchgear cabinet that is configured to physically accommodate the equipment and associated wiring. Such switchgear cabinets are additionally configured to provide a protective barrier between the switchgear within the cabinet and the technicians and other personnel working in the proximity of the exterior of the cabinet. 
     Previously known switchgear cabinets have typically been designed to be compatible with only a small number of different types of circuit breakers, with new switchgear cabinets needing to be designed for each new circuit breaker design. Each newly designed switchgear cabinet must undergo a rigorous safety testing regimen prior to production. The effort involved in the design and testing of each new cabinet configuration has been both costly and time consuming, thereby increasing the cost of each new line of circuit breakers as well as increasing the duration of the product development cycle. It is thus desired to provide an improved switchgear cabinet and, more particularly, a frame for a switchgear cabinet, that includes modular components which can be assembled and configured in different fashions to be compatible with different types of circuit breakers without requiring as much design or testing effort as previously known switchgear cabinetry. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, an improved frame for a switchgear cabinet includes a plurality of rails that are connected together with a plurality of connectors. The rails are generally of two different cross-sectional configurations, both of which are cooperable with a single type of connector to enable the rails and connectors to be configured into numerous different types of cabinet frames to which panels can be mounted to form switchgear cabinets. The rails and connectors are modular in nature and are specifically configured to be easily connected with one another. During assembly of the connectors and the rails, portions of a coating on the rails become ruptured, thereby electrically conductively connecting together the rails and the connectors. 
     Accordingly, an aspect of the present invention is to provide an improved cabinet frame that is relatively less expensive to design and test than previously known cabinet frames. 
     Another aspect of the present invention is to provide an improved cabinet frame that is relatively easy to assemble. 
     Another aspect of the present invention is to provide an improved cabinet frame that is modular in nature. 
     Another aspect of the present invention is to provide an improved cabinet frame that generally includes a plurality of rails and a plurality of connectors, with the rails being generally of two different cross-sections. 
     Another aspect of the present invention is to provide a cabinet frame assembled out of a plurality of rails and connectors, with the rails each including a coating, and with the coating being ruptured at one or more points to provide an electrically conductive connection between each rail and each associated connector. 
     Accordingly, an aspect of the present invention is to provide a connector for connecting together a plurality of rails to form a portion of a cabinet frame, the general nature of which can be stated as including a post and a plurality of clasping members, each clasping member being structured to be associated with one of the rails and to fasteningly extend between the associated rail and the post, each clasping member including a clip and a fastener, the clip being structured to be engageable with the associated rail, the fastener extending between the clip and the post, the clip including three engagement elements, the three engagement elements each being structured to engage the associated rail to retain the associated rail on the post, wherein a portion of the clip that extends between at least a pair of the engagement elements is structured to be disposed at least partially adjacent an outward-facing surface of the associated rail, and the fastener being generally centrally disposed between the three engagement elements. 
     Another aspect of the present invention is to provide a cabinet frame, the general nature of which can be stated as including a plurality of rails, each rail including an outward-facing surface, and a plurality of connectors, each connector including a post and a plurality of clasping members, each clasping member being associated with one of the rails and fasteningly extending between the associated rail and the post, each clasping member including a clip and a fastener, the clip being engaged with the associated rail, the fastener extending between the clip and the post, the clip including a first engagement element, a second engagement element, and a third engagement element that are each engaged with the associated rail to retain the associated rail on the post, wherein a portion of the clip that extends between at least a pair of the engagement elements is disposed at least partially adjacent the outward-facing surface of the associated rail, and the fastener being generally centrally disposed between the three engagement elements. 
     Still another aspect of the present invention is to provide a cabinet frame, the general nature of which can be stated as including a plurality of rails and a plurality of connectors, each rail including a first flange and a second flange oriented substantially parallel with one another and being separated from one another by an opening in the rail that extends substantially throughout the longitudinal extent of the rail, each rail including a cavity extending substantially throughout the longitudinal extent of the rail and being in communication with the exterior of the rail through the opening in the rail, each connector including a post and a plurality of clasping members, each clasping member being associated with one of the rails fasteningly extending between the associated rail and the post, and each clasping member including a clip and a fastener, the clip being engaged with the associated rail, the fastener extending between the clip and the post, the clip including a first engagement element, a second engagement element, and a third engagement element that are each engaged with the associated rail to retain the associated rail on the post, the first engagement element being engaged with the first flange, and the second engagement element being engaged with the second flange. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A further understanding of the invention can be gained from the following Description of the Preferred Embodiment when read in conjunction with the accompanying drawings in which: 
     FIG. 1 is an isometric view of a cabinet frame in accordance with the present invention; 
     FIG. 1A is an enlarged view of a portion of FIG. 1; 
     FIG. 2 is an exploded view of a portion of the present invention; 
     FIG. 2A is an exploded view of a portion of the present invention; 
     FIG. 3 is an end view of a first rail of the present invention; 
     FIG. 4 is an end view of a second rail and an auxiliary flange member of the present invention; 
     FIG. 5 is an isometric view of the auxiliary flange member; 
     FIG. 6 is a plan view of a portion of the present invention; 
     FIG. 7 is a view similar to FIG. 6, except being in an exploded configuration subsequent to initial assembly; 
     FIG. 8 is a side elevational view of a clip of the present invention; 
     FIG. 9 is a front elevational view of the clip; and 
     FIG. 10 is an isometric view of the clip. 
    
    
     Similar numerals refer to similar parts throughout the specification. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A cabinet frame  4  in accordance with the present invention is indicated generally in FIG.  1 . The cabinet frame  4  can be generally stated as including a plurality of rails  8  and a plurality of connectors  12  that are connected with one another. The rails  8  and the connectors  12  are generally of a modular configuration and thus can be assembled in different configurations to form numerous different types of cabinet frames. As will be set forth more fully below, the rails  8  and the connectors  12  are advantageously configured to permit the cabinet frame  4  to be easily assembled. It is understood that the cabinet frame  4  depicted generally in FIG. 1 is an example of one such cabinet frame, and that other cabinet frames of different configurations can be assembled out of the same rails  8  and connectors  12 . 
     The connectors  12  are depicted herein as being generally of only a single configuration, although it is understood that the connectors  12  may be of other configurations depending upon the specific needs of the particular application. As can be understood from FIGS. 2,  3 , and  4 , however, the rails  8  are generally of two different cross-sections such that each of the rails  8  is either a first rail  8   a  (FIG. 3) or a second rail  8   b  (FIG.  4 ). It is to be noted that the second rail  8   b  depicted in FIG. 4 includes an auxiliary flange member  16  mounted thereon that could alternatively or additionally be mounted on the first rail  8   a.    
     The first and second rails  8   a  and  8   b  are similar to one another, with the second rail  8   b  including an additional flange that is absent from the first rail  8   a . The first and second rails  8   a  and  8   b  can be employed in the cabinet frame  4  in various combinations depending upon the desired final configuration of the cabinet frame  4 . Additionally, and as will be set forth more fully below, the auxiliary flange member  16  is an optional structure that can be employed depending upon the specific needs of the particular application and can be mounted on either of the first and second rails  8   a  and  8   b.    
     As can be understood from FIGS. 3 and 4, each of the first and second rails  8   a  and  8   b  include a first flange  20 , a second flange  24 , a first leg  28 , a second leg  32 , and a base  36 , with the second rails  8   b  each additionally including a third flange  40 . It can be seen that the first and second legs  28  and  32  are generally parallel with one another and extend from opposite edges of the base  36 . The first flange  20  extends perpendicularly from an edge of the first leg  28  opposite the base  36 , and the second flange  24  extends perpendicularly from an edge of the second leg  32  opposite the base  36 . It can be seen that the first and second flanges  20  and  24  are substantially parallel and coplanar with one another. The rails  8  each terminate at a pair of opposite ends  68 . 
     The first leg  28 , the base  36 , the second leg  32 , and the second flange  24  together define a roughly rectangular cavity  44  that extends substantially throughout the longitudinal extent of each rail  8   a  and  8   b . The cavity  44  at least partially defines a receptacle  48  that can receive at least a portion of one of the connectors  12  therein. 
     With the cavity  44  being defined as being the interior of the rails  8   a  and  8   b , it can be seen from FIGS. 3 and 4 that the cavity  44  is in communication with an exterior of the rails  8   a  and  8   b  through an opening  52  that is interposed between the first and second flanges  20  and  24  and that extends substantially throughout the longitudinal extent of the rails  8   a  and  8   b . It can also be seen that the first flange  20  includes a first longitudinal edge  54  disposed adjacent the opening  52  and that the second flange  24  includes a second longitudinal edge  58  disposed adjacent the opening  52 . As will be set forth more below, by configuring the first and second rails  8   a  and  8   b  to include the opening  52 , the connectors  12  advantageously can be readily connected with the rails  8   a  and  8   b  due to the generally open configuration thereof. 
     It can be seen from FIG. 4 that the third flange  40  extends perpendicularly from the second longitudinal edge  58  of the second flange  24  of the second rail  8   b , with the third flange  40  extending from the second flange  24  in a direction generally away from the cavity  44 . As can be understood from FIGS. 1 and 2, the third flange  40  generally does not extend fully throughout the longitudinal extent of the second rails  8   b , but rather terminates short of the opposite ends  68  of the second rails  8   b  in order to avoid interference with portions of other rails  8  oriented perpendicular thereto at the connectors  12 . It will be further understood that end portions of one or more of the first and second flanges  20  and  24 , the first and second legs  28  and  32 , and the base  36  may be similarly foreshortened at the ends  68  of the rails  8   a  and  8   b , or at other regions thereof, in order to similarly avoid interference with other structures, although this is not specifically shown in the accompanying drawings. It is understood that such foreshortening may be necessary depending upon the specific configuration of the desired final cabinet frame. 
     With the cavity  44  again being defined as being the interior of the rails  8   a  and  8   b , each of the first leg  28 , the base  36 , the second leg  32 , and the second flange  24  include an outward-facing surface  56  (FIGS. 1A,  3 ,  4 ,  6 , and  7 ) that faces in a direction other than toward the cavity  44 . In this regard, it can further be seen that the first flange  20  and the third flange  40  each include a pair of opposed outward-facing surfaces  56  since the first and third flanges  20  and  40  are not disposed adjacent the cavity  44 , but rather are structures which generally protrude outwardly and away from the cavity  44 . 
     It can be, seen that the first, second, and third flanges  20 ,  24 , and  40 , and preferably also the first and second legs  28  and  32 , include a plurality of regularly spaced substantially circular holes  60  (FIGS. 1A,  6 , and  7 ) formed therein. The holes  60  are, in the present embodiment, configured to be non-threaded in order to cooperatively receive self-tapping screws or other such fasteners therein, as appropriate, for fastening various structures to the first and second rails  8   a  and  8   b . As can be understood from FIG. 1, the base  36  of one or more of the rails  8  may be formed with one or more connection bores  62  (FIG. 1) that can be used for connecting the cabinet frame  4  with another adjacent cabinet frame  4  or other structure with appropriate fasteners. 
     The first and second flanges  20  and  24  each additionally include a pair of generally rectangular apertures  64  formed therein, with each aperature  64  being disposed adjacent but spaced slightly from one of the ends  68  of each rail  8   a  and  8   b . Each aperture  64  defines a seat  72  on the rail  8  that is cooperable with a portion of one of the connectors  12 , as will be set forth more fully below. 
     Each rail  8  includes a coating  76  (FIGS. 6 and 7) such as a layer of paint or other such coating on each surface that is exposed to the atmosphere. The coating  76  may be configured to enhance aesthetics, to resist corrosion, for other purposes, or a combination of such purposes. 
     As is shown generally in FIG. 4, the auxiliary flange member  16  includes a generally planar first plate  80 , a generally planar second plate  84 , and a generally V-shaped junction member  88  interposed therebetween such that the auxiliary flange member  16  is generally W-shaped in cross section. The first and second plates  80  and  84  are oriented substantially perpendicular to one another and each include a plurality of the holes  60  formed therein. The auxiliary flange member  16  advantageously can be mounted on either of the rails  8   a  and  8   b  in order to provide an additional flange if needed, depending upon the specific needs of the particular application. As can be understood from FIG. 4, the auxiliary flange member  16  is connected with the second rail  8   b  with a plurality of fastening members  90  that fasteningly extend through pairs of aligned holes  60  formed in the auxiliary flange member  16  and the second rail  8   b . The fastening members  90  may be self-tapping screws, as suggested above, or may be other appropriate types of fasteners such as rivets, bolts, and the like. 
     With the auxiliary flange member  16  being mounted on the second rail  8   b  as depicted generally in FIG. 4, the second plate  84  of the auxiliary flange member  16  provides an additional flange that is generally coplanar with and parallel with the third flange  40 , albeit disposed on an opposite side of the second rail  8   b . It can be seen that the junction member  80  is configured to extend around the outward-facing surfaces  56  of the first leg  28  and the base  36 . It is understood, however, that the first plate  80  can be mounted on either of the first and third flanges  20  and  40 , and potentially may alternately be mounted on any of the second flange  24 , the first leg  28 , and the second leg  32 , depending upon the desired final configuration of the cabinet frame. 
     Each connector  12  includes a post  92  and three clasping members  96  that are cooperable with the post  92 . Each clasping member  96  includes a clip  100  and a fastener  104 . It can be understood from FIG. 2 that each clip  100  is cooperable with one of the rails  8 , and that each fastener  104  is cooperable with one of the clips  100 , whereby each post  92  can have three of the rails  8  securely connected thereto and oriented mutually perpendicular to one another. 
     The post  92  includes a body  106  and three protrusions  108  extending outwardly from the body  106  in mutually perpendicular directions therefrom. Each protrusion  108  includes a boss  112  and at least one fastener plate  116 , with the boss  112  protruding outwardly from the body  106  by a greater distance than the corresponding fastener plate  116 . Each fastener plate  116  includes a fastener bore  118  formed therein that is cooperable with the fastener  104 . The body  106  includes an attachment bore  124  formed therein and extending therethrough for purposes of enabling attachment of the post  92  to another structure as needed. It can be seen that the protrusion  108  which extends away from the body  106  in a direction generally parallel with the attachment bore  124  includes a pair of the fastener plates  116 , with a channel  120  being formed between each such fastener plate  116  and the boss  112 . 
     As can be understood from FIGS. 2,  6 , and  7 , the protrusions  108  are receivable in the receptacles  48  of the rails  8 . In the case of the protrusion  108  that includes a pair of the fastener plates  116 , it can be understood that the boss  112  and only one of the fastener plates  116  will be received in one of the receptacles  48  at any one time, with the additional fastener plate  116  and the channels  120  being provided to enable the rails  8  to be connectable in alternate orientations with the particular protrusion  108 . While not being particularly depicted in the accompanying figures, it can be understood that the bosses  112  and the fastener plates  116  are snugly receivable in the receptacles  48  in order to rotationally and transversely align the rails  8  with the protrusions  108  and with the post  92 . 
     As can be understood from FIG. 2, the fasteners  104  are received in the fastener bores  118  in an orientation that is oblique to the protrusions  108  as well as to the longitudinal extent of the rails  8 . As used herein, the expression “oblique” and variations thereof refers to a relative orientation that is neither perpendicular nor parallel. As will be set forth more fully below, the oblique orientation of the fasteners  104  with respect to the rails  8  securely engages the clips  100  with the rails  8  and securely retains the rails  8  in desirable positions with respect to the posts  92 . 
     As can be understood in FIGS. 6-9, each clip  100  includes a transverse portion  128  and a longitudinal portion  132  connected with one another. The transverse portion  128  includes a transverse shank  136 , a first engagement element  140 , and a second engagement element  144 , with the first and second engagement elements being disposed at opposite ends of the transverse shank  136  and extending in a direction generally perpendicular to the transverse shank  136 . The longitudinal portion  132  includes a longitudinal shank  148  extending from the transverse shank  136  and a third engagement element  152  extending from the longitudinal shank  148  opposite the transverse shank  136 . It can be seen that a slot  156  is formed in the longitudinal shank  148  near the third engagement element  152 . 
     It can be seen from FIG. 8 that the first and second engagement elements  140  and  144  are generally hook-shaped. The first engagement element  140  includes a first engagement surface  160 , and the second engagement element  144  includes a second engagement surface  164 , with both the first and second engagement surfaces  160  and  164  being generally hook-shaped. It can be seen that the third engagement element  152  includes a third engagement surface  168  that is at least partially arcuate. 
     The first, second, and third engagement surfaces  160 ,  164 , and  168  of each clip  100  are engageable with one of the rails  8  to retain the rail  8  on the post  92 . Specifically, the first and second engagement surfaces  160  and  164  are engageable with the seats  92  formed by the apertures  64  in the first and second flanges  20  and  24  near the ends  68 . The third engagement surface  168  is received against the base  36  within the cavity  44  generally opposite the opening  52 . 
     With the first, second, and third engagement surfaces  160 ,  164 , and  168  engaged with one of the rails  8  as such, the fastener  104  is received through the slot  156  formed in the clip  100  and is thereafter cooperatively received in the fastener bore  118  of the fastener plate  116 . If the fastener  104  and the fastener bore  118  cooperate threadably, the fastener  104  is rotated until tightened. 
     Since the fastener  104  is oriented oblique to the longitudinal extent of the rail  8 , the tightened fastener  104  imparts force components both parallel with and perpendicular to the longitudinal extent of the rail  8 . Such parallel forces cause the first and second engagement surfaces  160  and  164  to engage the seats  72 . Similarly, such perpendicular forces cause the third engagement surface  168  to engage the base  36 . It can also be seen that the first, second, and third engagement surfaces  160 ,  164 , and  168  together lie within two substantially perpendicular planes, i.e., one plane being substantially parallel with the longitudinal extent of the rail  8  and the other plane being substantially perpendicular thereto. By providing the first, second, and third engagement surfaces  160 ,  164 , and  168  within a pair of substantially perpendicular planes and by disposing the fastener  104  generally centrally among the first, second, and third engagement surfaces  160 ,  164 , and  168 , the different forces acting in different directions between the clip  100  and the rail  8  securely retain the rail  8  in a given position with respect to the post  92 . 
     It can further be seen that the rail  8  can be relatively easily connected with the post  8  since a substantial portion of the clip  100  is disposed at the exterior of the rail  8 . Specifically, it can be understood from FIGS. 1,  2 ,  6 , and  7  that the transverse shank  136  is disposed along the outward-facing surfaces  56  of the first and second flanges  20  and  24 . In this regard, the clip is attached to the rail  8  simply by receiving the first and second engagement elements  140  and  144  in the apertures  64  while the transverse shank  136  remains disposed at the exterior of the rail  8 . The third engagement element  152  becomes disposed within the cavity  44  yet is disposed generally opposite the opening  52 . It thus can be seen that the first, second, and third engagement surfaces  160 ,  164 , and  168  can be engaged with the rail  8  simply by translating the clip  100  with respect to the rail  8 . Further in this regard, since the fastener  104  is oriented oblique to the longitudinal extent of the rail  8 , the fastener  104  can be advanced with a conventional hand tool (not shown) since the head of the fastener  104  is disposed within or very near the opening  52  and is oriented away from the rail  8 . 
     It can be seen from FIG. 7 that each rail  8  includes a point of juncture  172  where the rail  8  contacts the body  106  of the post  92 . Similarly, each rail  8  includes a point of engagement  176  at each point where one of the first, second, and third engagement surfaces  160 ,  164 , and  168  engages the rail  8 . As can be understood from FIG. 7, engagement of the clip  100  with the rail  8  causes the coating  76  to rupture at the point of juncture  172  and at the points of engagement  176 , which facilitates an electrically conductive connection between the rail  8  and the connector  12  and which facilitates grounding of the cabinet frame  4 . In the circumstance where the coating  76  is a layer of paint, the forces involved with engaging the clip  100  with the rail  8  cause the paint to be chipped at the point of juncture  172  and at the points of engagement  176 . It is understood, however, that a rupture of the coating  76  at any of the points of engagement  176  or at the point of juncture  172  will provide the desirable electrically conductive connection between the rail  8  and the connector  12 . 
     It thus can be seen that by mounting the rail  8  to the post  92  with the clasping member  96 , the clip  100  is engaged with the rail  8 , and the fastener  104  fasteningly extends between the clip  100  and the post  92 . The clip  100  and the rail  8  are advantageously configured to allow the clip  100  to be readily engaged with the rail  8  after the protrusion  108  has been received in the receptacle  48 . The clip  100  is moved in a first direction to be received in the apertures  64  and in the cavity  44 , and upon tightening of the fastener  104  the clip is moved in a substantially perpendicular second direction to engage the seats  72  and the base  36 . 
     By orienting the fastener  104  oblique to the longitudinal extent of the rail  8 , the forces imparted to the clip  100  cause the first, second, and third engagement surfaces  160 ,  164 , and  168  to engage the rail  8  and securely retain the position of the rail  8  on the post  92 . Indeed, the fastener  104  causes the clip  100  to be wedged against the associated rail  8  in three different directions. 
     As can be understood from the accompanying drawings, the distance between adjacent holes  60  is substantially constant and is given by the dimension  180  (FIGS.  2  and  6 ). The width of the first flange  20  is given by the dimension  184  (FIG.  3 ), the width of the second flange  24  is given by the dimension  188 , the width of the third flange  40  is given by the dimension  192 , the width of the first leg  28  is given by the dimension  196 , the width of the second leg  32  is given by the dimension  200 , the width of the opening  52  is given by the dimension  202  and the width of the base  36  is given by the dimension  204 . As can be understood from the accompanying drawings, each of the dimensions  180 ,  184 ,  188 ,  192 ,  196 ,  200 ,  202 , and  204  are each equal to a multiple of a fixed characteristic length which, in the exemplary embodiment depicted in the accompanying figures, is 0.75 inches. More particularly, the dimensions  180 ,  184 ,  188 ,  192 ,  196 ,  200 , and  202  are equal to the characteristic length and the dimension  204  is twice the characteristic length. 
     Such a consistency in the aforementioned dimensions facilitates and enhances the modular nature of the rails  8  and the connectors  12  by permitting cooperability between components. For instance, the cooperation of the auxiliary flange member  16  with the second rail  8   b  as depicted in FIG. 4 results in the second plate  84  being disposed generally centrally along the base  36  and coplanar with the third flange  40 . Accordingly, by making each of the dimensions  180 ,  184 ,  188 ,  192 ,  196 ,  200 ,  202 , and  204  equal to a multiple of the characteristic length, the rails  8  can be configured in myriad ways to construct myriad different types of cabinet frames. It is understood, however, that the characteristic length can be any of a wide variety of fixed dimensions that are appropriate to specific needs of particular applications. It is further understood that sheet material from which the rails  8  are manufactured has a thickness, and thus some of the aforementioned dimensions may be measured from various surfaces or edges of the rails  8 , while other dimensions may be measured from other positions with respect to the rails  8 . 
     The rails  8  are also advantageously configured to be manufactured with conventional machinery found in most any factory or machine shop. Since the rails  8  of the present invention generally include a plurality of bends and holes formed in a flat sheet, and since the bends can be formed with conventional bending machinery, such as a box and pan brake, the rails  8  can be manufactured in diverse geographic locations using conventional equipment that is relatively inexpensive to purchase and maintain and that is generally available. 
     While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.