Abstract:
The PTV cabinetry of the present invention utilizes an integrally weighted base that enables the cabinet to satisfy load bearing and tip over standards without requiring the addition of separate weights. The base preferably includes a raised region and at least one lower region. Fill material is poured into the base, and substantially within the lower region, and allowed to set and harden. The fill material used is any suitable material having a density sufficient to act as a weight, such as, e.g., a concrete and fiber mixture or a metallic material. The raised region of the base may include a plurality of openings that allows heat to dissipate from within the interior space of the cabinet. The integrally weighted base of the present invention replaces a typical flat bottom panel of a typical PTV cabinet and further eliminates the need for attaching separate weights onto a bottom panel of a typical PTV cabinet.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to projection television sets, and more particularly to an integrally weighted base that prevents the tip over of a projection television enclosure.  
         BACKGROUND  
         [0002]    Projection televisions (PTVs) or “big screen” TVs are a popular alternative to traditional picture tube televisions because they provide comparably larger viewable screens that cannot be efficiently produced using conventional picture tubes. PTV cabinets are presently designed to hold electrical and optical components, as required, to decipher and project a television picture on a screen generally on the front of the cabinet. The most common PTV on the market today projects pictures created via appropriate electrical and optical components onto a mirror within a box containing the entire apparatus so that the picture reflected to a screen is as large as possible for the volume occupied by the cabinet enclosing it. Currently, PTV screens typically range in size from about 45 to about 73 inches along their diagonal, while the cabinets typically range in size from about 48 inches to over 65 inches in height, from about 38 inches to over 65 inches in width, and from about 22 inches to over 29 inches in depth. The cabinets are assembled in an aesthetically appealing manner as required to hold the electrical components, light generator(s), and lenses, mirror and screen in the relationship required to obtain the desired televised picture.  
           [0003]    Most PTVs marketed today include a cabinet constructed from multiple pieces of particleboard cut and glued together. Some cabinets also have plastic components held to the basic cabinet structure with screws or other fasteners. The number of plastic components and particleboard pieces needed to form such cabinets typically range in excess of fifty (50) pieces. Because of the size of PTVs, and the particleboard from which the cabinets are typically constructed, PTVs tend to be quite heavy and difficult to maneuver.  
           [0004]    Alternative methods of manufacture are available that may reduce the overall weight of these cabinets, the number of components necessary to construct such cabinets, and the overall depth of the cabinet. For instance, injection molding could be used to form such cabinets out of plastic. Another alternative would be to vacuum form the cabinetry out of plastic. The use of lighter weight materials to manufacture PTV cabinets leads to an additional problem in that the lighter weight cabinets are easier to tip over relative to the traditional particle board cabinets. For example, the manufacture of a cabinet that is smaller in depth relative to a traditional cabinet results in a cabinet with a smaller footprint to support a cabinet that is substantially the same height as a traditional PTV cabinet with a larger footprint. This results in variety of safety issues since, e.g., a PTV cabinet must meet load bearing, or tip over, standards. Current standards, such as, e.g., Underwriter&#39;s Laboratories load standards, require that a PTV cabinet must be able to withstand 25 lbs of force without tipping over. Without the addition of some weight to the base of a lighter, thinner PTV cabinet, the thinner PTV cabinet would be more likely to fail the UL tip over test than a traditional particle board cabinet. To address this problem, those skilled in the art currently add counterweights to the bottom of the lighter weight cabinets, which have generally flat bases formed from wood or particle board, in order to enable these cabinets to withstand at least 25 lbs of force without tipping over. Typically, the amount of weight added to the bottom of a PTV cabinet is determined using the following formula: Added Weight=(25 lbs)(Height of the Cabinet/Depth of the Cabinet).  
           [0005]    Turning to FIG. 1, a conventional cabinet  10  of a PTV  50  is illustrated. The conventional cabinet  10  includes top  12 , bottom  14 , front  16 , and rear  18  panels. Side panels connecting the front  16  and rear  18  panels are also included, but not illustrated. The conventional cabinet  10  is typically divided by an internal wall  24  into two compartments, i.e., an upper  20  and a lower  22  compartment. Cathode ray tubes (CRTs)  26  and printed wiring boards (PWBs)  30  are typically mounted in the lower compartment  22 , while a mirror M and a screen S are mounted in the upper compartment  20 . At least one projection lens  28  typically extends from the lower compartment  22  into the upper compartment  20  through the internal wall  24 . The upper compartment  20  is typically tightly sealed from the lower compartment  22  to protect the inside of the upper compartment  20  from dust and other foreign materials. The lower compartment  22  typically includes one or more sets of ventilation holes to exhaust heat radiating from the CRTs  26  and the PWBs  30 . As shown, the lower compartment  22  includes a first set of holes  32  positioned adjacent the top of the lower compartment  22  and a second set of holes  34  positioned adjacent the bottom of the lower compartment  22 . When the cabinet  10  is constructed using lighter weight materials and methods, such as those previously discussed, weights  36  must be positioned in the lower compartment  22 , and normally on top of the bottom panel  14 , in order to balance the cabinet  10 . Currently, weights  36 , which may be metal bricks, additional particle board base pieces, or any other suitable counterweights, are tied or otherwise physically attached to the bottom panel  14  of the cabinet  10 . The number of weights  36  used in the cabinet  10 , to enable the cabinet  10  to pass the UL tip over test, is determined with the aforementioned formula.  
           [0006]    The current methods for balancing a thinner, lighter PTV cabinet result in several disadvantages. For example, the use of additional particle board bases to increase the weight and stability of these cabinets often requires the additional use of forest products, thereby contributing to long term environmental deleterious effects. Also, the additional step of adding a separate weight to a cabinet increases the complexity and cost of producing the lighter weight PTV cabinets. There is also a danger that the weights may not be properly secured to the cabinet during construction, thereby resulting in safety issues should the weights become dislodged during transport of the cabinet, or during the lifetime of the cabinet. For example, the weights may become dislodged and repositioned in an area that causes the cabinet to become unbalanced and more likely to tip over.  
           [0007]    Those skilled in the art have failed to provide for a light weight PTV cabinet capable of passing standard load tests without the addition of costly counterweights. Thus, it would be desirable to provide for a PTV cabinet that is easy and less costly to manufacture, mitigates environmental damage due to a decreased reliance on wood for a counterweight, is less vulnerable to manufacturing irregularities, and reliably meets load/tip over standards for PTV cabinets.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention is directed to an improved enclosure or cabinet for PTVs. The PTV cabinet of the present invention includes an integrally weighted base formed with fill material that acts to stabilize the cabinet and enables the cabinet to satisfy load and tip over standards. The PTV cabinet of the present invention is particularly useful when implemented as part of a lighter weight PTV cabinet, but is also capable of being used with traditional, wood-based PTV cabinets.  
           [0009]    In one particularly innovative aspect of the present invention, a cabinet for a PTV includes a top portion housing a mirror, a plurality of CRTs, and a projection lens. The top portion preferably includes a top panel, a front panel, a rear panel, and side panels extending between the front and rear panels. Attached to the top portion, and opposite the top panel of the cabinet, is a base having at least one raised area, each raised area having a top surface, at least one lower region adjacent to each raised area, and a fill material deposited into each lower region. The base provides stability to the cabinet and enables the cabinet to satisfy standard load bearing requirements. The top surface of the raised region may include a plurality of vent openings allowing heat built up within the cabinet to dissipate therethrough. In another embodiment, additional elevated regions are present on the base that allow for components to be securably attached to the base. The fill material is preferably a material having a density greater than wood or of the panels of the cabinet. Exemplary fill materials include a concrete/fibrous material mixture and a metallic material.  
           [0010]    In another aspect of the present invention, a method of manufacturing a television cabinet having an integrally weighted base includes manufacturing a base having at least one raised region, at least one lower region adjacent each raised region, and a plurality of openings on a top surface of each raised region. A fill material, which may be any of the aforementioned materials, such as, e.g., a concrete/fibrous material mixture or a metallic substance, is poured into the base and allowed to set or harden. The fill material is typically poured substantially within the lower regions of the base, although some fill material may accumulate atop the raised region. After the fill material has set, the fill material is ground down such that the fill material is substantially level with the top surface of the raised region.  
           [0011]    Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with accompanying drawings. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a side view of a projection television set of the prior art.  
         [0013]    [0013]FIG. 2 is a side view of one embodiment of a PTV cabinet, having an integrally weighted base, of the present invention.  
         [0014]    [0014]FIG. 3 is a side view of the base of the PTV cabinet of the present invention illustrated in FIG. 2.  
         [0015]    [0015]FIG. 4 is a side view of another embodiment of the base of a PTV cabinet of the present invention.  
         [0016]    [0016]FIG. 5A is a top view of an embodiment of the base of a PTV cabinet of the present invention having parallel, length-wise openings.  
         [0017]    [0017]FIG. 5B is a top view of an embodiment of the base of a PTV cabinet of the present invention having parallel, width-wise openings.  
         [0018]    [0018]FIG. 5C is a top view of an embodiment of the base of a PTV cabinet of the present invention having a plurality of circular openings.  
         [0019]    [0019]FIG. 5D is a top view of an embodiment of the base of a PTV cabinet of the present invention having diagonally parallel openings.  
         [0020]    [0020]FIG. 6 is a side view of an embodiment of the base of a PTV cabinet of the present invention having a plurality of raised regions. 
     
    
     DETAILED DESCRIPTION  
       [0021]    The present invention is applicable to cabinets for a variety of devices or display devices that are subject to a standardized load bearing test. The following discussion, however, focuses on cabinets for PTV sets for exemplary purposes only. In one preferred embodiment, a base having a frame and fill material disposed within the frame is provided. The base is configured to conform to the shape of a cabinet to which it is to be attached, forming the bottom portion of the cabinet. Alternatively, the base may be formed with the fill material in the absence of a frame.  
         [0022]    Illustrated in FIG. 2 is one embodiment of a cabinet  110  of a PTV  100  using the present invention. The cabinet  110  includes a top panel  112 , a front panel  116 , a rear panel  118 , and side panels (not shown) extending between the front  116  and rear  118  panels and in further connection with the top panel  112 . Furthermore, a cabinet suitable for use with the present invention is not limited to one having a front, rear, and two side panels. Rather, the present invention is capable of use with a cabinet that has any plurality of side panels, such as, e.g., a cabinet shaped like an octagon. Additionally, a cabinet suitable for use with the present invention is not limited to a square or rectangle shaped cabinet but may be any suitable shape, such as, e.g., a trapezoidal shaped cabinet. The present invention is molded to conform with the specific shape of the cabinet that incorporates the invention.  
         [0023]    Turning back to FIG. 2, the cabinet  110  is preferably divided by an internal wall  124  into an upper  120  compartment and a lower  122  compartment. CRTs  126  and PWBs  130  are preferably mounted in the lower compartment  122 , and a mirror M and a screen S are preferably mounted in the upper compartment  120 . At least one projection lens  128  preferably extends from the lower compartment  122  into the upper compartment  120  through the internal wall  124 . The upper compartment  120  is preferably tightly sealed from the lower compartment  122  in order to protect the inside of the upper compartment  120  from dust and other foreign materials that might otherwise be introduced from the lower compartment  122 . The cabinet  110  is preferably constructed using light weight materials and methods, such as, e.g., molded plastic foam components formed from expanded polystyrene or phenolic that is sandwiched between coatings of an appropriate structural material such as plastic. Appropriate materials and methods to construct a cabinet using light weight materials are further described in copending U.S. patent application Ser. No. 09/643,892 to Lowe entitled “Foam Cabinetry for Electronic Devices,” which is fully incorporated herein. Alternatively, the top panel  112 , front panel  116 , rear panel  118 , and side panels (not shown) of the cabinet  110  may be constructed of particle board, or another wood-based material.  
         [0024]    Rather than a flat bottom panel typical of the prior art, such as, e.g., bottom panel  14  of cabinet  10  illustrated in FIG. 1, the cabinet  110  using the present invention includes a base  150 . The base  150  provides a footprint upon which the cabinet  110  is balanced. The base  150  preferably includes at least one raised region or area  152  and at least one lower region  154  adjacent each raised region  152 . The base  150  is preferably molded from a plastic compound or from a metallic compound. If the base  150  is formed from a metallic compound, the base  150  further acts as a radiation shield, i.e., a metallic base  150  provides an additional function of being able to reduce the emission of electromagnetic radiation through the lower compartment  116  of the cabinet  110 . In one embodiment, the base  150  is formed by placing the compound that will comprise the frame  151  of the base  150 , such as metal or plastic, into a master mold. The compound placed into the master mold is preferably initially in a substantially liquid state. After the compound hardens or sets, the compound is removed from the mold. The hardened compound forms the frame  151  of the base  150 .  
         [0025]    Turning to FIG. 3, a close-up, side view of one embodiment of the base  150  is shown. The embodiment of the base  150  illustrated in FIG. 3 includes the frame  151  and fill material  158  set within the frame  151  of the base  150 . The base  150  further includes a plurality of openings  156  on a top surface of the raised region  152  of the frame  151 . When present, the openings  156  allow for heat radiating from the components of the PTV, such as, e.g., the CRTs  126  and the PWBs  130 , to dissipate from the lower compartment  116 . To further increase heat dissipation from the lower compartment  116 , a set of holes  132  positioned on the rear panel  118  is optionally provided. One skilled in the art would understand that the location of the set of holes  132  may vary depending on the desired heat dissipation effect.  
         [0026]    A fill material  158  is poured into the frame  151  of the base  150 . Preferably, the fill material  158  is poured substantially within the lower region  154  of the frame  151 , although it is to be expected that some fill material  158  may also contact the raised region  152  during this process. In one embodiment, the fill material  158  is a concrete mixture. When concrete is used as the fill material, a fibrous material may be added to the concrete to provide structure within the concrete and to increase the tensile properties of the fill material. In another embodiment, the fill material  158  is a metallic material. In still other embodiments, the fill material  158  may be any other material that possesses a density greater than the material used to construct the panels of the cabinet  110 , and therefore a density and resultant weight sufficient to balance the cabinet  110 . For example, when the panels of the cabinet  110  are constructed of wood or particle board, the fill material  158  must exhibit a density greater than the density of the material used for the panels.  
         [0027]    After the fill material  158  is poured into the frame  151 , and into the lower region  154  of the frame  151 , the fill material  158  is allowed to set or cure. Preferably, once the fill material  158  solidifies, the top surface of the fill material  158  is ground down such that the top surface of the fill material  158  is substantially level with the top surface of the raised region  152 . The grinding process is preferably accomplished through mechanically abrasive methods, although chemicals may also be used during this process. In embodiments of the base  150  having the plurality of openings  156 , any fill material  158  covering the openings  156  is removed from the top surface of the raised region  152  during the grinding process.  
         [0028]    The base  150  is attached to the front panel  116 , the rear panel  118  and the side panels (not shown) of the cabinet  110 , opposite the top panel  112  of the cabinet  110 , to form the bottom surface of the cabinet  110 . The base  150  is secured to the front panel  116 , rear panel  118 , and side panels (not shown) using any suitable attachment method, such as, e.g., a suitable adhesive or brackets.  
         [0029]    The base  150  allows the cabinet  110  to be weighted in a manner suitable for satisfying industry standard load tests, such as, e.g., the UL tip over test, without the need for placing additional, individual weights, see, e.g., weights  36  of cabinet  10  in FIG. 1, inside the cabinet, unlike prior art cabinets. One advantage of base  150  over the prior art is that the possibility of individual counterweights, i.e., weights  36  of cabinet  10  in FIG. 1, becoming detached during manufacture, transport, or the life of the cabinet  10  is eliminated. Consequently, the ability of a cabinet using base  150  to satisfy standardized load bearing tests is ensured.  
         [0030]    Turning now to FIG. 4, another embodiment of the base  250  of the present invention is illustrated. Base  250  has a frame  251  that further includes a plurality of elevated portions  252  disposed within the lower regions  154  of the frame  251 . Although two elevated portions  252  are illustrated, any multiple number of elevated portions  252  may be implemented in base  250 . The elevated portions  252  are configured for securably attaching thereto a component of the PTV, such as, e.g., the PWB  130 , to the base  250 . Each portion  252  includes an opening (not shown) configured for securably inserting an attachment element, such as, e.g., a screw, therein. In practice, for example, the PWB  130  is placed atop the elevated portions  252  prior to the coupling of the base  250  to the cabinet, and attachment elements are inserted through the PWB  130  and into each opening of each respective portion  252 . As a result, the PWB  130  is secured to the base  250 .  
         [0031]    [0031]FIGS. 5 a - 5   d  illustrate top views of several embodiments of the present invention, showing possible configurations for the openings  156  of the base  150 . FIG. 5 a  illustrates a base  150   a  having openings  156   a  that are oriented parallel relative to each other and also extend along the length of a raised region  152  and of the base  150   a . FIG. 5 b  illustrates a base  150   b  having openings  156   b  that are oriented parallel to each other but that extend along the width of a raised region  152  and of the base  150   b . FIG. 5 c  illustrates a base  150   c  having openings  156   c  that are circular in shape and that are dispersed throughout a raised region  152  of base  150   c . FIG. 5 d  shows a base  150   d  having diagonally oriented openings  150   d  on the raised region  152 . Other configurations and shapes of openings are also capable of being implemented on the base of the present invention. One skilled in the art would appreciate that the configurations and shapes of the openings of the raised region  152  may vary based upon the desired heat dissipation effect, for example.  
         [0032]    The present invention also provides for PTV cabinet with a base having a plurality of raised regions. Turning to FIG. 6, a base  350  is illustrated that includes frame  351  having a plurality of raised regions  352 . Although two raised regions  352  are shown, it is envisioned that many multiple numbers of raised regions  352  may be implemented in base  350 . As with the previous embodiments of the base, the frame  351  of base  350  further includes lower regions  354  adjacent to each raised region  352 . Fill material  358  is poured into the frame  351 , and substantially within the lower regions  354 , allowed to set or harden, and then ground down to be substantially level with the top surface of the raised regions  352 . The base  350  illustrated in FIG. 6 also includes a plurality of openings  356 , to allow for heat dissipation, on the top surface of the raised regions  356 . Any fill material  358  that may have accumulated over these openings  356  during the pour and set processes are ground away in order to keep the openings  356  unobstructed.  
         [0033]    The particular examples set forth herein are instructional and should not be interpreted as limitations on the applications to which those of ordinary skill are able to apply this device. Modifications and other uses are available to those skilled in the art which are encompassed within the spirit of the invention as defined by the scope of the following claims.