Abstract:
A vented non-metallic cap for equipment pedestals having high heat generating components is disclosed. The cap is constructed of a plastic base and a plastic top cover with a stainless steel insect screen between these elements. The base includes a central opening to allow the interior of a covered pedestal to vent heated air generated by newer equipment, and yet the appearance of the vented cap is similar to existing metal pedestal top covers, but has far superior thermal performance.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a pedestal cap and more particularly to a vented non-metallic cap for a pedestal containing high heat generating components.  
           [0003]    2. Description of the Related Art  
           [0004]    Equipment pedestals such as those used for telecommunications, cable television and the like are well known. See, for example, U.S. Pat. No. ______(co-pending application Ser. No. 09/366,982) and U.S. Pat. No. 4,631,353. The data transmission equipment enclosed in such pedestals generate heat, however, usually this does not create any undue problem because the pedestal is able to radiate and/or conduct the heat to the ambient environment thereby preventing damage to the electronic equipment within the pedestal. However, with new high speed data, video electronics and optical devices, the amount of heat generated has grown and has become a problem. Such equipment may generate heat upwards of 23 watts. It is required that ambient air temperature around optical devices not exceed 65° C. while those devices are operating. Furthermore, this critical temperature is to be achieved using only passive thermal management techniques; actively powered cooling devices may not be specified.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    The difficulties arising due to increased heat generation have been overcome by the present invention. What is described here is a vented cap for an outdoor equipment pedestal having an appearance and size similar to existing pedestal top covers and comprising a base having an open center portion and a peripheral vent, a screen mounted to and supported by the base, an impact cover mounted to the base above the screen, and a fastener for connecting the base and the cover.  
           [0006]    There are a number of advantages, features and objects achieved with the present invention which are believed not to be available in any earlier related device. For example, one advantage is that the present invention provides a vented pedestal cap having superior thermal performance characteristics compared to existing pedestal top covers. Another object of the present invention is to provide a vented pedestal cap which allows good passive interior ventilation. A further advantage of the present invention is to provide a vented cap that fits existing pedestals from a size standpoint and also has a similar appearance so as not to detract from the pedestal&#39;s aesthetics. Still another aspect of the present invention is to provide a vented pedestal cap having good impact resistant qualities. Yet another advantage of the present invention is to provide a vented pedestal cap which is made of several parts that are easily, quickly and inexpensively made and assembled. A further object of the present invention is to provide a vented pedestal cap which is strong, chemical resistant, flame retardant and highly weatherable. An additional aim of the present invention is to provide an insect screen as part of the cap so as to shield the interior of the pedestal from environmental contaminants.  
           [0007]    A more complete understanding of the present invention and other objects, advantages, features, aspects and aims thereof will be gained from a consideration of the following description of the preferred embodiment read in conjunction with the accompanying drawing provided herein. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0008]    [0008]FIG. 1 is a generalized elevation view of an equipment pedestal partially buried underground having the vented cap of the present invention.  
         [0009]    [0009]FIG. 2 is an enlarged exploded downward looking isometric view of the three parts of the vented cap of the present invention.  
         [0010]    [0010]FIG. 3 is an upward looking isometric view of the cover of the vented cap shown in FIGS. 1 and 2.  
         [0011]    [0011]FIG. 4 is a sectional elevation view taken along line  4 - 4  of the FIG. 2.  
         [0012]    [0012]FIG. 5 is a sectional elevation view taken along line  5 - 5  of FIG. 2.  
         [0013]    [0013]FIG. 6 is an upward looking isometric view of the base of the vented cap shown in FIGS. 1 and 2.  
         [0014]    [0014]FIG. 7 is a sectional elevation view taken along line  7 - 7  of FIG. 2.  
         [0015]    [0015]FIG. 8 is a sectional elevation view taken along line  8 - 8  of FIG. 2. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    While the present invention is open to various modifications and alternative constructions, the preferred embodiment shown in the drawing will be described herein in detail. It is understood, however, that there is no intention to limit the invention to the particular form disclosed. On the contrary, the intention is to cover all modifications, equivalent structures and methods, and alternative constructions falling within the spirit and scope of the invention.  
         [0017]    The new cap disclosed herein has much better thermal performance characteristics when compared to existing caps. Even though the cap resembles prior art top covers, the new cap provides for enhanced ventilation while having superior impact resistance, chemical resistance, flame retardation and weather capabilities. Referring now to FIG. 1, there is illustrated a pedestal  10  having a pedestal housing  12  and an interior chamber  13 , part of which is located below ground level. Ground level is represented by a wavy line  14 . Within the pedestal is a mounting plate  15  for supporting terminal blocks that receive and pass on electronic signals from a cable  16  to a line  17 . At the top of the pedestal is the vented cap  18  of the present invention. As mentioned above, new high speed data, video electronics and optical devices need to dissipate considerably more heat than earlier electronics. It is estimated that the new heat range is approximately twenty three watts. To allow existing pedestals to continue to be used to house the new electronics, the new cap of the present invention has been developed.  
         [0018]    Referring now to FIG. 2, the vented cap  18  is shown in an exploded view to better appreciate its simplicity. The vented cap includes a top cover  20 , an insect screen  22  and a vented base  24 . As will be explained below, fasteners, such as the screw  26 , pass upwardly through the base  24  to attach to the top cover  20 . This forms a compact but aesthetically pleasing vented cap that is quick and easy to make, assemble and install. The cap is also rugged enough to achieve superior impact resistance.  
         [0019]    Referring now to FIGS.  2 - 5 , the top cover includes a shallow pyramid shaped top wall  30  fashioned to closely resemble the unvented caps now in prominent use. Under the top wall and at the four corners of the cover, there are screw receiving sleeves,  32 ,  34 ,  36 ,  38 . A downward projecting skirt wall  40  is attached to the top wall and a series of support tabs, such as the tab  42 , are spaced around the interior of the top cover by the intersection of the skirt wall and the top wall. Each of the support tabs has a bottom edge, such as the edge  44  of the tab  46 , for abutting a peripheral edge surface  48 , FIG. 2, of the base  24 .  
         [0020]    The top cover  20  may be made of any suitable material, such as PVC, with an wall thickness of about 0.200 inches. The top cover may be made by injection molding of the entire item so that the top surface, the skirt, the support tabs and the screw receptacles are all integral. The base  24  may also be molded in one piece of PVC resin where the wall thickness is approximately 0.125 inches.  
         [0021]    Referring now to FIGS. 2, 6,  7  and  8 , the base  24  has a lower periphery portion  50  and an upper peripheral portion  52 . Connecting the lower and upper peripheral portions and spaced around the base periphery are a series of support ribs, such as the rib  54 . The lower peripheral portion  50  includes an outer wall  56 , a slanted floor  58  and an inner wall  60 . The inner wall  60  defines a central opening  62 . At the upper portion of the inner wall  60  is a support edge  64 . The support edge  64  and the tops of each of the support ribs, such as the rib top edge  66 , all lie in a common horizontal plane and they act to support the insect screen  22 . At the interior junction of the outer wall  56  and the floor  58  are a series of support tabs, such as the tabs  68 ,  70 . The support tabs of the base each include a slot, such as the slot  72  of the tab  74 . These slots receive a top edge  76  of the pedestal housing  12  to support the vented cap. Lateral screw holes, such as the holes  78 ,  80 , are provided to receive screws (not shown) to fasten the vented cap to the walls of the pedestal.  
         [0022]    The upper peripheral portion  52  of the base includes a peripheral vertical wall  82  and a border floor  84 . The support ribs, such as the rib  54 , are connected to the border floor  84  and the inner wall  60 . The vertical wall  82  is connected to four comer screw sleeves  85 ,  86 ,  87 ,  88 . The vertical wall  82  also surrounds and protects the screen  22  and has the upper peripheral edge surface  48  for supporting the top cover  20 .  
         [0023]    It can now be seen that a ventilation path is formed from the pedestal chamber through the opening  62 , over the edge  64 , through the screen  22 , above the floor  58  and between the support ribs. This is shown by the curved arrow  90 , FIGS. 2 and 7.  
         [0024]    The screen  22  is sixteen mesh,  304  stainless steel whose openings are squares of about 0.053 inches per side and with an open area of about seventy-two percent.  
         [0025]    To assemble the vented cap, the screen  22  is placed over the support edge  64  of the inner wall  60  and over the top surfaces  66  of the support ribs where it is heat-staked to energy directors. Thereafter, the cover  20  is placed over the peripheral edge  48  of the base. Hi-Lo screws are then received by the comer screw sleeves of the base and the receiving sleeves of the top cover. When the screws are tightened, the vented cap  18  is completely assembled. The ventilation flow path passes through the screen so that venting from the interior of the pedestal is allowed but insects and debris from outside the pedestal are restricted from entering. Further, when the cap is fastened to the pedestal, the Hi-Lo screws are hidden from view and from tampering.  
         [0026]    The geometry of the base and the cover enhance impact resistance of the cap and also provides a tight seal over the pedestal. The top cover and base may each be easily molded as integral pieces and assembled easily so as to eliminate any additional insulation. The cap also has an appearance and size of existing pedestal top covers so as to facilitate replacement.  
         [0027]    The specification describes in detail one embodiment of the present invention. Other modifications and variations will under the doctrine of equivalents come within the scope of the attached claims. For example, slight dimensional or geometry changes are considered equivalent structures as are different materials. Still other alternatives will also be equivalent as will many new technologies. There is no desire or intention here to limit the application of the doctrine of equivalents.