Abstract:
A decorative trim assembly for unit doors on a motor control unit. The decorative trim assembly comprises individual bezels that provide information about the motor control unit while distinguishing the motor control unit from other motor control units. Posts project from the back surfaces of the bezels and are received in holes in the unit doors. Retaining clips frictionally engage the posts and secure the bezels to the unit doors. Additional bezels are modularly connected to the secured bezel. The secured bezel contains a camouflaged cutout member that allows access to the unit door latch when removed. The unit door may be hingeably attached to the motor control unit along one edge of the unit door, and the unit door may contain quarter-turn latches along an opposing edge to secure the unit door to the motor control unit.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a decorative trim assembly for unit doors on a motor control system, and, more particularly, to bezels modularly connected to define the face layout on a unit door on a motor control system. 
     Trim bezels are typically used for concealing an opening between an electrical component and the panel in which it is mounted. They are usually decorative in appearance or contain indicia pertinent to the instrumentation of the system. For example, a bezel may be printed with the words “on” and “off” for use around a breaker, or it may indicate the name or some other identifying mark of the system on which it is installed. Bezels are usually installed directly to the panel or fascia using tabs, clips, screws, bolts, or a combination of these methods. 
     The major problem with some of the prior art bezels is that they often have to be custom made for the component interface around which they are mounted. Custom made bezels are generally more expensive than mass-produced bezels and sometimes add significantly to the costs of the finished product. Even if the bezels are not custom made, prior art bezels are usually of a standard shape and design that do not allow the past offerings of a product line to be easily differentiated from the current offerings of the same product line. 
     Moreover, in designing the face layout and assembling an electrical panel, individual trim pieces are separately attached to the surface of the unit door. The installation of additional instrumentation also requires the installation of an additional bezel. In the prior art, adding bezels would require attaching each individual bezel using screws. Typically, these screws would be installed from the back of the instrument panel. The use of a screw as a means of attaching and securing each individual bezel, along with having to open an electrical box to install the screw from the back of the door of the electrical box, increases the costs involved with assembling the finished product. 
     SUMMARY OF THE INVENTION 
     In an exemplary embodiment of the invention, a decorative trim assembly for unit doors on a motor control center defines the individual components situated on the unit doors. Bezels are mounted to the door around components such as meters and switches. The bezels are modularly connected using bushings and receiving holes in each bezel, and are secured to the unit door with posts integrally mounted on the back sides of each bezel and retaining clips. In one alternate embodiment, mounting screws and tabs that slidably engage slots in the unit door may be used to secure each bezel to the unit door. A lip may be attached or molded into at least one edge of the bezel to allow the bezel to be easily grasped while being removed or pulled away from the unit door. The pilot device bezel may also contain a removable cutout member that allows access to a hidden door latch. The inventive decorative trim bezels may be attached to a unit door that is hingeably attached to the motor control center and contains quarter-turn latches that allow the door to be secured to the motor control center while still allowing access to the internal components of the motor control center. 
     The modularity of the inventive design allows for the manufacture and assembly of only a few different pieces, thus minimizing the unique part count. Furthermore, the modular assembly approach allows many different pieces to be combined to accommodate the configurations of standard height motor control units as well as the configurations of extended height motor control units. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of the decorative trim pieces, of the present invention, being positioned on the front of a unit door; 
     FIG. 2 is an exploded perspective-view of the decorative trim pieces, of the present invention, with an additional embodiment, of the present invention, being positioned on the front of the unit door; 
     FIG. 3 is a perspective view of a back side of a pilot device bezel, of the present invention, showing a detailed view of a post and a retaining clip; 
     FIG. 4 is a perspective view of a back side of an alternate embodiment, of the present invention, showing a detailed view of a tab; 
     FIG. 5 is a perspective view of the mounting hole on the back side of the pilot device bezel, of the present invention; 
     FIG. 6 is a perspective view of the front side of an alternate embodiment of the pilot device bezel, of the present invention, showing a door defeater access hole and a pull lip; 
     FIG. 7 is a perspective view of the back side of the alternate embodiment of the pilot device bezel, of the present invention, showing the door defeater access hole and the pull lip; 
     FIG. 8 is a side elevated view of a bushing integrally formed on the bezel extension frame, of the present invention; 
     FIG. 9 is a perspective view of an alternate embodiment of the breaker bezel, of the present invention, being positioned on the front of the unit door; 
     FIG. 10 is a perspective view of the back side of a unit door, of the present invention, having hinges positioned along one side for hingedly attaching the unit door to a motor control center, and showing quarter turn latches for securing an opposing side of the unit door to the motor control center; and 
     FIG. 11 is a perspective view of a unit door hingedly attached to a motor control center. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a decorative trim assembly, which can also be referred to as a decorative trim molding, of an exemplary embodiment of the present invention is shown generally at  10 . Decorative trim assembly  10  includes a pilot device bezel  12 , a bezel cover  14 , a breaker bezel  16 , and a name plate  18 , all of which are situated on a unit door  20  of a motor control center. An alternate embodiment of decorative trim assembly  10 , as shown in FIG. 2, contains a bezel extension frame  22 . Pilot device bezel  12  is shown in FIGS. 1 and 2 as being generally rectangular in shape and having a front side  24  which faces away from unit door  20 , a back side  26  which faces and engages unit door  20 , and a central opening  28  which is slightly smaller than a face of an instrument interface  30  over which pilot device bezel  12  is mounted. 
     Referring to FIG. 3, a means for securing pilot device bezel  12  to unit door  20  is illustrated. At least one post  32  is attached to back side  26  of pilot device bezel  12  proximate a first edge  34  of pilot device bezel  12 , and is configured and dimensioned to be received in a corresponding number of post holes  36 . At least one post  32  is positioned proximate a second edge  46  of pilot device bezel  12  and is likewise configured and dimensioned to be received in a corresponding number of post holes  36 . Retaining clips  37  are inserted over the portion of posts  32  received through post holes  36  and are dimensioned to be frictionally retained on posts  32  thus securing pilot device bezel  12  to unit door  20 . 
     In FIG. 4, an alternate embodiment of the invention is shown in which a tab  132  is used to retain pilot device bezel  12  on unit door  20 . Tab  132  is an L-shaped structure wherein a first leg  140  projects from back side  26  while a second leg  142  is received in a slot  136 . Second leg  142  extends along a longitudinal axis of slot  136  to engage an interior surface  21  of unit door  20 , thus allowing tab  132  to be retained in slot  136  when pilot device bezel  12  is moved in the direction of arrow  138 . 
     Turning now to FIG. 5, in the above-mentioned alternate embodiment, a mounting hole  144  may be used to further secure pilot device bezel  12  to unit door  20 . Mounting hole  144 , used in conjunction with tabs  132 , is shown integrally formed proximate second edge  46  of back side  26  of pilot device bezel  12 . Mounting hole  144  may be configured to threadedly receive a mounting screw  148  inserted from the interior surface (not shown) of unit door  20 . A mounting washer  150  may be positioned between the head of mounting screw  148  and mounting hole  144  and should be of sufficient size to keep the head of mounting screw  148  from passing through a screw hole (not shown) in unit door  20 . 
     Referring back to FIGS. 1 and 2, receiving holes  54  are situated along first edge  34  on front side  24  of pilot device bezel  12 . Receiving holes  54  are dimensioned and configured to snappingly receive bushings  56  integrally formed on bezel extension frame  22  and bezel cover  14  which connect bezel extension frame  22  or bezel cover  14  to pilot device bezel  12 . Bushings  56  are described in greater detail below with reference to FIG.  8 . 
     Front side  24  of pilot device bezel  12  also contains a camouflaged cutout member  58 . Camouflaged cutout member  58  is snappingly attached to pilot device bezel  12  and is concavely oriented relative to the outer surface of unit door  20  to conceal a latching mechanism (not shown). Removal of camouflaged cutout member  58  allows access to the latching mechanism thus enabling unit door  20  to be opened without turning off a circuit breaker switch  60 . 
     Referring now to FIGS. 6 and 7, another embodiment of the pilot device bezel is shown generally at  112 . Pilot device bezel  112  attaches to unit door  20  in a conventional manner, such as via hinged elements (not shown) disposed along one edge of the flat planar member of the molding; however, pilot device bezel  112  contains a lip  113  defining a “finger grab” area along an edge opposing the edge on which the hinged elements are disposed. Lip  113  allows a person to grasp the edge of pilot device bezel  112  and pull pilot device bezel  112  away from the face of unit door  20 . Also shown is an access hole  119 , which allows the latching mechanism on unit door  20  to be accessed and defeated, thereby enabling unit door  20  to be opened when the circuit breaker switch (not shown) is in the “on” position. 
     Referring back to FIG. 2, bezel extension frame  22  is shown as a rectangular frame similar in structure to pilot device bezel  12  and having a front side  62  which faces away from unit door  20 , a back side  64  which faces and engages unit door  20 , and a central opening  66  which is slightly smaller than the face of instrument interface  30  around which bezel extension frame  22  is mounted. Bezel extension frame  22  contains at least one post  32  attached to back side  64  of bezel extension frame  22  proximate a first edge  68  of bezel extension frame  22 . Post  32  is configured and positioned in a fashion similar to that of pilot device bezel  12  and assists in retaining bezel extension frame  22  on unit door  20  when bezel extension frame  22  is mounted to unit door  20  in a manner similar to the mounting of pilot device bezel  12 . Receiving holes  54  similar to those on pilot device bezel  12  for receiving bushings  56  are situated on front side  62  along first edge  68  of bezel extension frame  22 . 
     Referring now to FIG. 8, bushing  56  is shown in greater detail. At least one bushing  56  is integrally formed on a second edge  70  of back side  64  of bezel extension frame  22 . Bushing  56  projects cylindrically from back side  64  of extension frame bezel  22  and is of a sufficient axial length to be snappingly received in receiving holes  54  disposed in pilot device bezel  12  or another extension frame bezel  22 . The combination of posts  32  received in post holes  36  and bushings  56  snappingly received in receiving holes  54  of pilot device bezel  12  or another extension frame bezel  22  secure bezel extension frame  22  to unit door  20 . Because of the combination of receiving holes  54  and bushings  56  on each bezel extension frame  22 , a plurality of bezel extension frames  22  can be modularly connected to each other. 
     Referring back to FIGS. 1 and 2, bezel cover  14  is shown as a flat planar member securable to pilot device bezel  12  or extension frame  22  in order to hide receiving holes  54  in pilot device bezel  12  or extension frame  22  and to give a pleasing appearance to pilot device bezel  12  or extension frame  22 . Bezel cover  14  has bushings  56  extending normal to a back side  74  of bezel cover  14  which are of a sufficient axial length to be snappingly received in a corresponding number of receiving holes  54  in pilot device bezel  12  or extension frame  22 . Bezel cover  14  is “snapped into” receiving holes  54  by aligning bushings  56  with receiving holes  54  and moving bezel cover  14  in the direction of an arrow  39 . 
     Still referring to FIGS. 1 and 2, breaker bezel  16  is shown as being generally rectangular in shape and having a central opening  76  that receives and accommodates breaker switch  60 . Breaker bezel  16  is configured similarly to pilot device bezel  12 . For example, breaker bezel  16  contains at least one post  32  on a back side  77  of breaker bezel  16  to be received in post holes  36  in unit door  20  and retaining clips  37  used to retain posts  32  in post holes  36 . Posts  32  received in post holes  36  enable breaker bezel  16  to be secured to unit door  20  in a manner similar to that of pilot device bezel  12 . 
     An alternate embodiment of breaker bezel  16  is shown in FIG. 9 generally at  116 . In the interest of saving space on the front of unit door  20 , if a hole through which breaker switch  60  is positioned is too proximate any other device mounted on unit door  20 , part of breaker bezel  16  can be removed leaving breaker bezel with only three sides. The missing fourth side of breaker bezel  16  is then positioned adjacent the proximately-situated device on unit door  20 . Posts  32  still engage post holes  36  to retain breaker bezel  116  on unit door  20 . 
     Again referring to FIGS. 1 and 2 show name plate  18  as being structured similarly to pilot device bezel  12  and breaker bezel  16 . Name plate  18  is generally rectangular in shape and has a front side  78  which faces away from unit door  20 , a back side  80  which faces unit door  20 , and at least one post  32  configured and positioned in a fashion similar to that of pilot device bezel  12  and bezel extension frame  22  integrally formed on back side  80  of name plate  18 . Front side  78  is generally planar and has a flat surface on which can be printed or embossed a logo, name, or some other defining characteristic of the motor control center. Post  32  received in post hole  36  allows name plate  18  to be secured to unit door  20  in a manner similar to that of pilot device bezel  12  and breaker bezel  16 . 
     Referring now to FIGS. 10 and 11, a unit door is shown generally at  220 . Unit door  220  is attached along one edge utilizing hinges  215  to a motor control center shown at  221  in FIG. 11, thereby causing unit door  220  to swing away from motor control center  221  when an edge opposing the hinged edge is not secured to motor control center  221 . Also shown in FIGS. 10 and 11 are quarter turn latches  217  positioned along the unhinged edge of unit door  220  on a back side  226  of unit door  220 . Quarter turn latches  217  are configured to be accessed from a front side  224  of unit door  220  using a screwdriver or similar tool (not shown). In a closed position, quarter turn latches  217  are received in slot openings shown at  229  in FIG.  11  and cause unit door  220  to be retained against motor control center  221 . Accessing and rotating quarter turn latches  217  from front side  224  of unit door  220  causes quarter turn latches  217  to rotate out of slot openings  229  allowing unit door  220  to swing freely away from motor control center  221 . 
     While this invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.