Abstract:
A weather resistant cabinet for housing electrical equipment includes a one-piece, unitary tubular housing. The tubular housing has two open ends and is preferably formed from aluminum using a deep-drawing process. Two covers are attached to the two open ends of the tubular housing. The two covers include heat sinks and are preferably formed from aluminum using an extruding process. The covers are attached to the tubular housing using either mechanical fasteners and a gasket, or by a dip-brazing process.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a weather resistant cabinet. More specifically, the present invention relates to a weather resistant cabinet for containing electrical equipment, which cabinet is easy to manufacture and assemble, and which cabinet provides convective heat dissipation for the electrical equipment contained within. 
     2. Description of the Background Art 
     Various weather resistant cabinets are known in the existing arts. For example, in the telecommunications field, electrical equipment located in the field, such as a junction terminal on a phone pole or a supplemental cellular base station on a bridge underpass, is contained within a weather resistant cabinet. 
     In the example of the supplemental cellular base station, one known weather resistant cabinet is the TDMA (Time Division Multiple Access) electronics enclosure. The TDMA enclosure includes six aluminum extrusions parts and miscellaneous sheet metal parts. The various parts are overlapped and joined to one another. In joining the parts, a special epoxy may be used, and/or a hole may be drilled through the overlapped portions and a simple pop rivet installed. Alternatively, a riv-nut may be installed in an inner hole and a threaded fastener passed through an outer hole to attach the overlapped inner and outer holes, and thereby the inner and outer overlapped portions. 
     The TDMA enclosure has several disadvantages. First, many components are required which bears on the manufacturing cost. Second, these many components must be assembled which bears on the assembly cost. Third, the interconnection between the component parts tends to leak moisture into the enclosure which leads to electrical malfunctions. These malfunctions necessitate service operations and replacement of electrical equipment. 
     The leaks occur because the rivets, over time, loosen. Further, because of the many component parts, each overlap is considered a leak risk due to manufacturing tolerances. Also, the thermal expansion rate of the various components will differ and, over time, the overlaps and rivets will deteriorate and develop leaks. 
     Accordingly, there exists a need in the art for a weather resistant cabinet having a limited number of component parts which are simple and inexpensive to manufacture, wherein the component parts may be easily assembled to form the cabinet, and wherein the interconnections between the component parts do not leak moisture or debris from the environment into the interior of the cabinet. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a primary object of the present invention to provide a weather resistant cabinet having component parts which are simple in design and relatively less expensive to manufacture. 
     Another object of the present invention is to provide a weather resistant cabinet having component parts which may be easily assembled to form the cabinet. 
     Yet another object of the present invention is to provide a weather resistant cabinet having component parts which do not leak moisture or debris from the environment into the interior of the cabinet. 
     These and other objects of the present invention are fulfilled by providing a cabinet for housing electrical equipment comprising: tubular housing and said first cover; and at least one fastener interconnecting said first cover and said tubular housing while compressing said first gasket wherein said first cover includes a frame having a third opening and a panel, in the form of a ribbed heatsink, attached to said frame by dip-brazing so as to close said third opening in said frame. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is a perspective view of a tubular housing having two open ends; 
     FIG. 2 is a perspective view of a cover having heat sinks; 
     FIG. 3 is an exploded view of a weather resistant cabinet, in accordance with the present invention; 
     FIG. 4 is a close-up cross sectional view illustrating a connection between the cover and the tubular housing, in accordance with a first embodiment; 
     FIG. 5 is a close-up cross sectional view illustrating a connection between the cover and the tubular housing, in accordance with a second embodiment; 
     FIG. 6 is cross section view of a first gasket taken at line VI—VI of FIG. 3 
     FIG. 7 is an exploded view of a weather resistant cabinet having a modified tubular housing, in accordance with the present invention; and 
     FIG. 8 is an exploded view, similar to FIG. 7, illustrating fasteners holding the housing together. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring in detail to the drawings and with particular reference to FIG. 1, a tubular housing  1  in accordance with the present invention is illustrated. The tubular housing  1  is formed as a one-piece, unitary body. The tubular housing  1  has a first open end  2  and a second open end  3 . The second open end  3  is rectangular and is defined by a lip  4 . Four threaded through holes  5  are provided in the lip  4 , adjacent to the corners of the rectangular second open end  3 . 
     The tubular housing  1  also includes four threaded studs  6  mounted within blocks  7 . The blocks  7  are attached to inner surfaces of the tubular housing  1 . The studs  6  extend outwardly of the first open end  2 . 
     To form the tubular housing  1 , a sheet of aluminum is placed over a die and a deep-drawn process is used to shape the aluminum. Later, the threaded through holes  5  are formed in the lip  4  by a tap, and the blocks  7  are welded to the inner surfaces of the tubular housing  1 . Deep-drawn manufacturing processes using aluminum have enjoyed wide spread usage and success in the automotive manufacturing and luggage manufacturing industries. Therefore, the particulars of the processes will not be described in detail herein. Of course, other known manufacturing techniques could be used to form the tubular housing  1 . 
     FIG. 2 illustrates a first cover  8 . The first cover  8  is generally shaped as a flat, rectangular plate. Four smooth through holes  9  are bored through the first cover  8  adjacent to the corners thereof. One face of the first cover  8  includes a plurality of heat sinks  10 . The other face of the first cover  8  has a recessed shelf  11  formed along the perimeter edges (See FIGS.  3 - 5 ). 
     To form the first cover  8 , aluminum is extruded through a mold. After extrusion, portions of the aluminum material may be removed or polished to shape the upper and lower features of the first cover  8 , and the through holes  9  are drilled through the recessed shelf  11 . Of course, other known manufacturing techniques could be used to form the first cover  8 . 
     FIG. 3 illustrates the component parts of a weather resistant cabinet, in accordance with the present invention. The component parts include the first cover  8 , a doorframe  12 , a first gasket  13 , the tubular housing  1 , and a second cover  14 . The second cover  14  is identical in structure to the first cover  8 . 
     Reference will be made to FIG. 4 to illustrate the manner of attachment between the second cover  14  and the tubular housing  1 . As illustrated, the recessed shelf  11  is sized to overlap the lip  4 . A second gasket  15  is provided between the overlapped portions. The smooth through holes  9  of the second cover  14  will align with the threaded through holes  5  in the lip  4 . Then, a threaded fastener  16 , such as a screw, will be used to attach the second cover  14  to the tubular housing  1 . 
     FIG. 5 illustrates an alternative manner of interconnecting the second cover  14  to the tubular housing  1 . In FIG. 5, the recessed shelf  11  is again overlapped with the lip  4 , however in this embodiment, there are no threaded through holes  5 , smooth through holes  9 , or threaded fasteners  16 . In this embodiment, a dip-brazing technique, similar to soldering, is used. In dip-brazing, a special compound  17  is applied between the overlapped recessed shelf  11  and the lip  4 . The assembly is heated and the compound adheres the recessed shelf  11  to the lip  4 , while deforming to fill in any irregular contours therebetween. 
     Now, referring back to FIG. 3, the assembly of the front of the weather resistant cabinet will be described. The doorframe  12  is a generally flat planar sheet having a central opening  18  and four smooth through holes  24  formed in the corners thereof. The first cover  8  is attached to the doorframe  12  with its recessed shelf  11  overlapping the perimeter of the opening  18 . The attachment between the first cover  8  and the doorframe  12  is preferably accomplished by the dip-brazing technique described above. 
     The first gasket  13  is sandwiched between the outer perimeter of the tubular housing  1  and the doorframe  12 . When the doorframe  12  is properly aligned with the tubular housing  1 , the threaded studs  6  will pass through the smooth though holes  24  of the doorframe  12  and the smooth though holes  9  of the front cover  8 . Lastly, threaded fasteners, such as nuts, are applied to the threaded studs  6  to secure the doorframe to the tubular housing  1  while compressing the first gasket  13 . FIG. 6 is a cross section view illustrating the first gasket  13 . Preferably, the first gasket  13  includes a first portion  19  and a second portion  20 . The first portion  19  has a protruding V-shape, and the second portion  20  has a mating recessed V-shape. The first portion  19  would be affixed to the outer perimeter of the tubular housing  1  prior to assembly, and the second portion  20  would be affixed to the outer perimeter of the doorframe  12  prior to assembly. Of course, the first portion  19  could be affixed to the doorframe  12  and the second portion  20  could be affixed to the tubular housing  1 . 
     FIG. 7 illustrates an alternative embodiment of the present invention. The alternative embodiment includes a modified tubular housing  21 , modified doorframe  22 , and modified gasket  23 . Essentially, the outer contours of the modified component parts have been reshaped to approximate a rectangle, so as to better accommodate a particular size and spacing of the electrical equipment inside the cabinet. The interconnections between the component parts are accomplished in a manner as described above. FIG. 7 illiustrates the second cover  14  being attached to the tubular housing  1  by a dip-brazing technique, in accordance with FIG.  5 . Of course, the second cover  14  could alternatively be attached to the tubular housing  14  using other manners, such as the threaded fasteners  16  of FIG.  4 . 
     FIG. 8 illustrates another alternative embodiment of the present invention, similar to FIG.  7 . In FIG. 8, a second modified gasket  23 ′ is disposed between the second cover  14  and the tubular housing  21 . A second plurality of holes  9 ′ are formed in the second cover  14 . A plurality of fasteners, in the form of threaded shafts  30  are provided. Each threaded shaft  30  passes through one of the first plurality of holes  9  in the first cover  8  and through one the second plurality of holes  9 ′ in the second cover  14 . Threaded fasteners, such as nuts  31 , are applied to the threaded shafts  30  to interconnect the first cover  8 , the tubular housing  21 , and the second cover  14  while compressing the first and second gaskets  23 ,  23 ′. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.