Abstract:
The subject matter under consideration is directed to filter racks that can be assembled and installed to hold filters and filter elements in a forced air-circulating environment such as a heating and air conditioning system. The filter rack has longitudinal members that are assembled to form a rectangular frame using readily available hardware. The longitudinal members include two side members and a back member, preferably made from the same material and having the same cross sectional profile, as well as a front member and a door. The cross-sectional profile of the side members, back member, and the front member include flanges to provide a filter rack that can receive and retain a rectangular filter when assembled.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to U.S. Provisional Patent Application No. 60/498,783 filed Aug. 29, 2003. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The subject matter of the invention under consideration is directed to a filter rack that can be assembled and installed to securely and removably retain a filter and filter element in a forced air-circulating environment such as a heating and air conditioning system.  
       BACKGROUND OF THE INVENTION  
       [0003]     Filter racks are provided in commercial and residential forced air circulating systems, such as heating ventilation and air conditioning (“HVAC”) systems, to house or hold filters. Filters are used in HVAC systems to remove allergens and other pollutants to ensure good air quality. Some types of filters include flat filter assemblies made from corrugated paper and other porous materials.  
         [0004]     Installation and operation of HVAC systems requires an extensive network of positive flow air flow ducting that carries circulating air throughout the building, as well as return air flow ducting which returns air from the building to the furnace or air conditioner for heating, cooling, or other conditioning and recirculation. Such ducting is typically rectangular in cross section, and formed from sheet metal such as aluminum or galvanized steel. Filters are commonly provided at the terminus of the return air flow ducting so that air is filtered before re-entering the air intake for the furnace or air conditioner. Such filters are held by racks that are positioned between the ducting and the air intake.  
         [0005]     The design and configuration of filter racks can vary from system to system. Some filter racks are built into the housing of the air conditioner or furnace, while others are designed to be installed in, and attached, to the return air flow ducting. One drawback of many filter racks is that they are made from steel, which has poor anti-corrosion properties and is therefore not suitable for humidified air supplies. Moreover, most filter racks are crudely assembled and installed in the field. For example, overlapping long metal strips are positioned to form a comer, and then screws are driven through the overlapping strips to fasten them in place. These inferior assemblies and methods result in filter racks having non-square comers, comer gaps, excessive vibration, low corrosion resistance, and other undesirable qualities. As a result, remedial measures, such as application of duct tape or caulking material to comers and surrounding ductwork, are commonly necessary. Such remedial measures result in only marginal improvements, and require additional labor on installation, and additional maintenance or replacement costs throughout the service life of the system.  
         [0006]     Therefore, what is needed is a filter rack for insertion into ductwork of a forced air circulating system that can be easily assembled and that provides a rigid, corrosion-resistant and air tight assembly.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides a filter rack for a forced air-circulating system, the filter rack comprising a plurality of longitudinal members having flanges adapted to receive and retain a filter and having channels adapted to receive and retain a connector, each longitudinal member adapted for connection to at least one other longitudinal member to form a rectangular frame; and a plurality of connectors adapted for insertion into the channels for connecting each longitudinal member to at least one other longitudinal member.  
         [0008]     The present invention further provides a method of assembling a filter rack for a forced air-circulating system, the method comprising the steps of providing a plurality of longitudinal members, each longitudinal member having flanges adapted to receive and retain a filter and having channels adapted to receive and retain at least one connector, each longitudinal member adapted for connection to at least one other longitudinal member to form a rectangular frame, the longitudinal members comprised of a front, at least two sides, and a back; providing a plurality of connectors adapted for insertion into the channels for connecting each longitudinal member to at least one other longitudinal member; and connecting each longitudinal member to at least one other longitudinal member using the plurality of connectors so as to form a rectangular frame.  
         [0009]     One advantage of the instant invention is that it provides a filter rack that is adapted for easy and reliable assembly and installation into a forced air-circulating system using only hand tools, such as a screwdriver. Another advantage is that the filter rack components are simple and inexpensive to manufacture, such as by aluminum extrusion methods that produce lightweight, corrosion resistant components having consistent and reproducible qualities. Still another advantage is that the filter rack can be packaged and shipped unassembled in component or kit form, thereby saving shipping space and associated costs.  
         [0010]     Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a three-quarter top view of an embodiment of the filter rack of the present invention.  
         [0012]      FIG. 2  is an exploded view of a corner of the filter rack of  FIG. 1 , illustrating the preferred connector apparatus and comer assembly.  
         [0013]      FIG. 3  is a cross sectional view of a side member taken along line III-III of  FIG. 1 .  
         [0014]      FIG. 4  is a cross sectional view of the front member taken along line IV-IV of  FIG. 1 .  
         [0015]      FIG. 5  is a cross sectional view of the door member taken along line V-V of  FIG. 1 .  
     
    
       [0016]     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0017]      FIG. 1  illustrates one embodiment of the filter rack  10  of the present invention. The filter rack  10  has a substantially rectangular shape, when assembled, and is formed from a plurality of longitudinal members, which include two substantially parallel side members  12 , a back member  14  substantially perpendicular to the side members  12 , and a front member  16  opposite the back member  14  and substantially perpendicular to the side members  12 . The side members  12 , back member  14 , and front member  16  are made or formed from an extruded rigid material such as plastic, composites, aluminum, or corrosion-resistant coated metal. More preferably, the rigid material used to form the side members  12 , back member  14 , and front member  16  is extruded aluminum.  FIG. 1  further illustrates that the filter rack  10  has a door  18  that can be mated with or assembled to the front member  16 , and possibly the side members  12 , to form a substantially airtight connection. The door  18  can be attached to the front  16 , and possibly also to one or both of the side members  12 , by any suitable detachable connecting system or technique, such as screws, bolts, hook and loop type fasteners, tabs, clamps, hinges and the like. Preferably the door  18  is attached using at least one bolt passing through an aperture in the front member  16  and through a corresponding aperture in the door  18 , the bolt is removably secured by at least one wing nut that can be accessed from the outer perimeter of the assembled filter rack  10 .  
         [0018]     As shown in  FIG. 1 , the front member  16  of the filter rack  10  is configured so as to provide an opening  20  for a filter (not shown) to be inserted into a receiving channel to pass into the filter rack and engage flanges  102 ,  104  in the front member  16 , side members  12  and back member  14 .  
         [0019]      FIG. 3  illustrates the cross-sectional profile of a side member  12 . In a preferred embodiment of the present invention, both side members  12  and the back member  14  have the same cross sectional profile as illustrated in  FIG. 3 . The side member  12  has a first flange member  102 , a second flange member  104  perpendicular to the first flange member  102 , and a “L” shaped member  106  connecting the first flange member  102  and the second flange member  104 . The “L” shaped member  106  has a first linear section  108  that is attached to the second flange  104  and is aligned substantially perpendicular to the second flange  104 . The “L” shaped member  106  further includes a second linear section  110  having a first end  112  end attached to the first flange  102 , and an opposite end  114  attached to the first linear section  108 . In one embodiment, the first linear section  108  and second linear section  110  are one continuous piece. The second linear section  110  is aligned substantially perpendicular to the first flange  102  and the first linear section  108 . The first linear section  108  further includes a protruding flange or ridge  120  that is disposed substantially perpendicular to the first linear section  108 . The protruding ridge  120  is disposed opposite a corresponding protruding ridge  120 A located on the end of the first flange member  102 , the protruding flanges  120 ,  120 A and the second linear section  110  form a rectangular channel  122  in the side member  12  (and back member  14 ) that can be used to receive connecting hardware. The first flange member  102  and second flange member  104  are adapted for mounting into an air handling system. Preferably, the second flange member  104  contains mounting means such as mounting holes  128  for attachment to ductwork or air handling equipment.  
         [0020]      FIG. 4  shows a cross-section of a preferred embodiment of the front member  16  for use in conjunction with the side members  12  and back member  14  as illustrated in  FIG. 2 . The front member  16  contains a first flange member  102  connected to an “L”-shaped member having an abbreviated first linear section  108 A, the first linear section  108 A and first flange member  102  are connected by a second linear section  110  that is substantially perpendicular to the first linear section  108 A and first flange member  102 . The first linear section  108 A further includes a protruding flange  120  that is disposed substantially perpendicular to the first linear section  108 A. The protruding ridge  120  is disposed opposite a corresponding protruding flange  120 A located on the end of the first flange member  102 , the protruding flanges  120 ,  120 A and the second linear section  110  form a rectangular channel  122  that can be used to receive connecting hardware.  
         [0021]      FIG. 5  shows a cross-section of a preferred embodiment of the door  18  for use in conjunction with the side members  12  and back member  14  as illustrated in  FIG. 2 , and with the front member  16  as illustrated in  FIG. 4 . The door  18  has a flange member  104 A connected to one end of an abbreviated first linear section  108 B, and an “L”-shaped portion  116  connected to the opposite end of the abbreviated first linear section  108 B. The abbreviated linear section  108 B contains a protruding flange  132  that is disposed substantially perpendicular to the abbreviated linear section  108 B. The flange  132  and “L”-shaped portion  116  are arranged and configured so that the door  18  can be mated to the front member  16  to form an airtight assembly. When mated, the cross-sectional profile of the connected door  18  of  FIG. 5  and front member  16  of  FIG. 4  have a collective cross-sectional profile substantially similar to that of the side members  12  and back members  14  illustrated in  FIG. 3 .  
         [0022]     The hardware used to assemble the filter rack may include one or more connectors  124  (see  FIG. 2 ) for joining the longitudinal members to form a rectangular frame. In the preferred embodiment shown in  FIG. 2 , each longitudinal member is adapted for interconnection with other longitudinal members, such as by including ends cut at 45 degree angles, and including at least one channel  122  for securely receiving connectors  124 . Preferably, the connectors  124  are flat L-shaped connectors  124  having one or more connector plates  130 , each connector plate  130  having at least two leg portions. However, any connector  124  which can attach two longitudinal members to form a 90 degree angle can be used, such as, for example, a flat connector bent to form a 90 degree angle, or any other suitable comer hardware.  
         [0023]     In the embodiment illustrated in  FIG. 2 , fasteners  126  such as one or more screws or bolts threaded through each leg of a connector plate  130  are used to secure the connector plate  130  in the channel  122  to connect the longitudinal members. To connect two longitudinal members at right angles, one leg of each connector plate  130  is inserted into a channel  122  in one longitudinal member. The channel  122  is shaped and sized to securely receive and retain the leg and is preferably a substantially “U”-shaped channel formed by one or more protruding ridges  120 ,  120 A extending over the channel  122  to prevent the connector plate  130  from leaving the channel  122 . The remaining leg of the connector plate  130  is inserted into a corresponding channel  122  in another longitudinal member to form a corner. Each connector plate  130  leg is then secured, preferably by adjusting the fastener  126  to move and position the fastener  126  against the face of the first linear section  110 , (or a second connector plate  130 ) and forcing the connector plate  130  upwards until the rear face of the connector plate  130  contacts at least one ridge  120 ,  120 A to frictionally and securely engage each connector plate  130  leg in its respective channel  122 , thereby forming a framed corner. Alternative embodiments contemplated hereunder permit use of any available corner hardware and corresponding receiving configuration incorporated in the longitudinal members. For example, tapered connectors or connectors having high-friction surface edges can be used to frictionally engage correspondingly-sized channels in the longitudinal members so as to eliminate the need for fasteners  126  such as threaded bolts or screws in the connector  124 . In still another embodiment, the fasteners  126  can be positioned through the plate and longitudinal member to form a connection, such as by inserting a screw through corresponding holes in the connector and the member.  
         [0024]     In one embodiment, the disclosed invention is a fully assembled rectangular filter rack which can be installed in heating and air conditioning systems to securely house one or more rectangular filters. In another embodiment, the disclosed invention can be provided disassembled in a filter rack kit that includes the back  14 , side  12 , and front  16  members, the door  18 , and a plurality of connectors  24  sufficient to form a rectangular filter rack when assembled.  
         [0025]     While the invention has been described with reference to a preferred embodiment, 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 embodiment 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.