Abstract:
A modular air vent assembly kit can be used to cover duct openings that supply a flow of heated or cooled air to a room in addition to covering duct openings that receive return air from a room. The modular air vent assembly kit is comprised of a frame, a base, a damper mechanism, and two different face plates where the damper mechanism can be selectively assembled into the base depending on whether control through the air vent by operation of a damper is needed in the particular duct opening and where either of the two face plates may be selectively connected with the base where one face plate has a lattice and is used in combination with the damping mechanism and the other face plate has a series of louvers and is used when the damping mechanism is not used in the vent assembly. The frame is secured to an air duct opening and the base and attached face plate are removably attachable to the frame without the need for separate fasteners.

Description:
This is a Continuation-In-Part Patent Application of patent application Ser. No. 09/638,817, filed Aug. 14, 2000 and now U.S. Pat. No. 6,302,784. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention pertains to a modular air vent assembly kit that can be used to cover duct openings that supply a flow of heated or cooled air to a room in addition to covering duct openings that receive return air from a room. In particular, the modular air vent assembly kit of the invention is comprised of a base, a damper mechanism, and two different faceplates where the damper mechanism can be selectively assembled into the base depending on whether control through the air vent by operation of a damper is needed in the particular duct opening and where either of the two faceplates may be selectively connected with the base where one faceplate has a lattice and is used in combination with the damping mechanism and the other faceplate has a series of louvers and is used when the damping mechanism is not used in the vent assembly. In a further embodiment of the modular air vent assembly kit, the kit includes a frame that can be secured to an air duct opening using conventional fasteners. The frame is constructed to receive the base of the kit in an internal volume of the frame and attach to the base without the requirement of separate fasteners. With the kit including the frame, the frame can first be secured to an air duct opening and then the base can be assembled with or without a damper mechanism and air filter and can then be secured in the frame without the use of separate fasteners. The face plate can then be secured to the base with the border of the face plate overlying the attachment of the frame to the air duct opening obstructing the attachment from view and giving the assembled modular air vent assembly a more aesthetic appearance. 
     (2) Description of the Related Art 
     In many HVAC systems, and in particular in HVAC systems used in households, the network of air ducts that make up the system communicate with two groups of outlets or openings, one group providing an outlet for cooled or heated air and the other group providing an inlet for return air to the HVAC system. These two different groups of openings are usually covered by two different types of air vent assemblies. 
     Air vent assemblies that cover return air openings or inlets of HVAC systems are commonly constructed as rectangular panels that have a grill or a series of louvers that conceal the return air inlet opening but do not appreciably restrict the flow of return air through the inlet opening. The panels typically have two or more fastener holes in the panels that receive threaded fasteners used in attaching the panels to a wall or ceiling surface. The heads of the fasteners are visible in the panel&#39;s fastener holes and detract from the aesthetic appearance of the panels. 
     Air vent assemblies that cover air outlet openings of the HVAC system typically include some type of damper mechanism that can control the flow of air through the outlet opening. The damper mechanism is assembled into a base of the air vent assembly and can be operated to completely close the air outlet opening and to open the air outlet opening in varying degrees. The outlet air vent assembly also includes a faceplate that is attached to the base and conceals the damper mechanism and the air outlet opening from view, but does not appreciably obstruct the flow of air through the outlet opening. The faceplate includes a lattice that conceals the air outlet opening, and the lattice can be constructed as a series of louvers or can be given a more ornamental appearance. 
     The need for having two different types of faceplates to cover air outlet openings and air inlet openings of an HVAC system contributes to the overall cost of the system. Air return or air inlet vent assemblies are typically comprised of a base that connects the assembly to the air return opening of the HVAC system and also connects with an air return faceplate that is specifically adapted for the particular base. In a like manner, air outlet vent assemblies are typically comprised of a base that attaches to the outlet opening of the HVAC system and includes the damper mechanism that is attached in the base, and the air outlet faceplate that covers over the base with the base, damper mechanism and faceplate being a pre-assembled unit. 
     SUMMARY OF THE INVENTION 
     The modular air vent assembly of the present invention is specifically designed to reduce the cost of HVAC systems by providing a kit of component parts that are used in both securing an air inlet faceplate over an air return duct opening of an HVAC system and in securing an air outlet faceplate and damper mechanism over an air outlet duct opening of an HVAC system. The air vent assembly kit of the invention is comprised of a frame, a base, a damper mechanism, and a pair of faceplates with one faceplate being intended for use in covering an air return inlet opening and the other faceplate being intended for use in covering an air outlet opening. The frame is designed to be inserted and secured in both an air outlet opening and an air inlet opening. The base is designed to be received and securely held in the frame without requiring separate fasteners and to have either of the faceplates selectively connected to the base. The base is also designed to have the damper mechanism selectively connected to or assembled in the base where desired. Thus, the base can be assembled into a frame that has been attached to an air return opening without a damper mechanism in the base, or the base can be assembled into a frame that has been attached to an air outlet opening with the damper mechanism assembled in the base. With the base assembled in an air return opening, the desired faceplate of the two faceplates of the kit can be selectively connected to the base by connectors of the faceplate that are inserted into the base and connect the faceplate to the base without separate fasteners. In a like manner, with the base containing a damper mechanism assembled into an air outlet opening of an HVAC system, the desired faceplate of the two faceplates can be selectively connected to the base by inserting connectors of the faceplate into the base and thereby connecting the faceplate to the base without separate fasteners. In both situations a border of the face plate overlies the fasteners that secure the frame to the air duct opening and thereby give the installed air vent assembly a more aesthetic appearance with the fasteners hidden from view. 
     By providing a frame and base that can be used in air return openings and air outlet openings and by providing a set of faceplates that can be selectively connected to the same base whether they cover an air return opening or an air outlet opening, the modular air vent assembly kit of the present invention simplifies the assembly of the HVAC system and reduces the number of parts needed in assembling the HVAC system and thereby reduces the costs of its assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features of the invention are revealed in the following detailed description of the preferred embodiment of the invention and in the drawing figures wherein: 
     FIG. 1 is a perspective, exploded view of the air vent assembly kit of the invention; 
     FIG. 2 is a side elevation view of an end wall of the base of the invention prior to forming; 
     FIG. 3 is an end view of the base end wall of FIG. 2 following its forming; 
     FIG. 4 is an elevation view of the second base end wall prior to its forming; 
     FIG. 5 is an end view of the end wall of FIG. 4 following its forming; 
     FIG. 6 is an elevation view of either of the side walls of the base prior to its forming; 
     FIG. 7 is a top plan view of the side wall of FIG. 6 following its forming; 
     FIG. 8 is an end elevation view of the side wall of FIG. 6 following is forming; 
     FIG. 9 is a plan view of a louver prior to its forming; 
     FIG. 10 is a plan view of the louver of FIG. 9 following its forming; 
     FIG. 11 is an end elevation view of the louver of FIG. 9 following its forming; 
     FIG. 12 is an elevation view of the louver actuator; 
     FIG. 13 is an end view of the louver actuator of FIG. 12; 
     FIG. 14 is a plan view of the lattice face plate of the kit; 
     FIG. 15 is a plan view of the louvered face plate of the kit; 
     FIG. 16 is a plan view of the assembled air vent assembly kit with the lattice face plate; 
     FIG. 17 is a side section view of the assembled air vent assembly kit of FIG. 16; 
     FIG. 18 is an end section view in section of the assembled air vent assembly kit of FIG. 17 along the line  18 — 18 ; 
     FIG. 19 is a partial section view of the louvered face plate of FIG. 15 from along the line  19 — 19 ; 
     FIG. 20 is a top plan view of the frame of the invention; 
     FIG. 21 is a side, sectioned view of the frame of FIG. 20; 
     FIG. 22 is a top plan view of an alternate embodiment of the base; 
     FIG. 23 is a side, sectioned view of the base shown in FIG. 22; 
     FIG. 24 is an end elevation view of one end of the base of FIG. 22; 
     FIG. 25 is an end elevation view of the second end of the base of FIG. 22; 
     FIG. 26 is an exploded assembly view of the face plate of FIG. 14, the base of FIG.  22  and the frame of FIG. 20; 
     FIG. 27 is a sectioned, side view of the face plate, base and frame of  26  in their relative assembled positions; 
     FIG. 28 is a partial perspective view of a portion of the base of FIG. 22; 
     FIG. 29 is an end elevation view of the base of FIG. 1 that has been modified for use with the frame of FIG. 20 together with an insert used with the modified base; 
     FIG. 30 is a top plan view of the insert employed with the modified base of FIG. 29; 
     FIG. 31 is an end elevation view of the modified base of FIG. 29 with the insert received on the base; and 
     FIGS. 32 and 33 show a fastener assembly that may be used with either of the face plates of FIGS. 14 and 15 in securing the face plate to a surface while maintaining the aesthetic appearance of the face plate and eliminating the need for the frame shown in FIG.  20 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The air vent assembly kit of the invention can be assembled in two different configurations, one of those two configurations being shown in FIG.  1 . The air vent assembly configuration assembled from the kit shown in FIG. 1 includes a face plate  12 , a base  14 , and a damper mechanism  16 . The other assembled configuration of the air vent assembly from the air vent assembly kit of the invention includes the same base  14  shown in FIG. 1 assembled to a different, second face plate  18  shown in FIG.  15 . The second configuration of the air vent assembly assembled from the air vent assembly kit of the invention does not include the damper mechanism  16 . In the preferred embodiment of the kit of the invention, both the first face plate  12  and second face plate  18 , as well as the component parts that make up the base  14  and the damper mechanism  16  are all stamped from sheet metal making the air vent assembly kit of the invention inexpensive to manufacture. However, other materials such as plastics may be employed in constructing the component parts of the kit of the invention. 
     The base  14  of the kit is constructed from a first base end wall  22  shown in FIGS. 2 and 3, a second base end wall  24  shown in FIG. 4 and 5 and a pair of identical base side walls  26  shown in FIGS. 6 and 7. 
     The two base end walls  22 ,  24  are not identical as the first base end wall  22  is slightly smaller than the second base end wall  24 . FIG. 2 shows the first base end wall  22  as a flat, stamped piece of sheet metal. The end wall is formed with a top edge  34  and a parallel bottom edge  36 , and opposite side edges with upper side edges  38  being spaced slightly farther apart than lower side edges  42 . The first end wall is formed with a pair of oblong openings  44  adjacent is top edge  34  and with four smaller circular openings  46  that extend across the end wall adjacent its transition between the upper side edges  38  and the lower side edges  42 . Just above the circular openings  46  the first end wall has two fold or bend lines  48 . In the final construction of the first end wall  32  it is folded along the two bend lines  48  to the configuration shown in FIG.  3 . 
     The second end wall  24  shown in FIG. 4, like the first end wall described above is a flat stamped piece of metal with a top edge  52  and an opposite bottom edge  54 . However, the distance between the top edge  52  and bottom edge  54  of the second end wall is slightly larger than that of the first end wall. The second end wall is also formed with opposite side edges which include upper side edges  56  that are spaced farther apart than the bottom side edges  58 . The second end wall also has oblong openings  62  adjacent its top edge  52  and four smaller circular openings  64  that extend across the end wall adjacent the transition between the upper side edges  56  and the lower side edges  58 . The second end wall is also provided with a pair of fold or bend lines  66  that extend across the end wall. In addition, the bottom edge  54  of the second end wall has a notch  68  with a fold line  72  that extends across the bottom of the end wall from the notch. The notch  68  and the second fold lines  72  define a pair of flanges  74  that project outwardly from the second end wall  24  when the second end wall is bent along the bend lines  66 ,  72  to the configuration shown in FIG.  5 . 
     The two base side walls  26  are the same and only one is shown in FIG.  6  and FIG.  7 . In FIG. 6 the side wall is shown as a flat blank stamped from sheet metal including a top edge  82  and an opposite bottom edge  84  and opposite side edges that include upper side edges  86  and lower side edges  88 . A fold or bend line  92  extends across the side wall adjacent the bottom edge  84  and defines a flange  94  that extends across the bottom of the side wall for almost its entire length. Pairs of two rectangular cut outs  96 ,  98  are made in the side wall adjacent but spaced from the bottom edge  84 . An arcuate strip  102  of side wall material is left between the two rectangular cut outs  96 ,  98 . Two more fold lines  104 ,  106  are formed in the side wall just above the pairs of rectangular cut outs  96 ,  98 . Two circular indentations are made in the side wall that form circular projections  108  on the interior surface of the side wall. A pair of curved cut out lines are made in the side wall adjacent the pair of circular projections  108  that form tabs or projections  112  having a general L-shape. The upper side edges  86  of the side walls are spaced slightly farther apart than the lower side edges  88 , and the upper side edges  86  are formed with flaps  114  that project from fold lines defined by the upper side edges  86 . 
     In forming the side walls  26  of the base into their final configuration shown in FIG. 7, each of the bottom flanges  94 , the arcuate strips  102 , the L-shape tabs  112  and the side edge flaps  114  are bent in the same direction from the side wall as shown in FIG.  7 . The side walls are also bent along the two intermediate fold lines  104 ,  106  in the manner shown in FIG. 7 to complete the construction of each side wall. 
     The first end wall  22  and the second end wall  24  are assembled to the pair of side walls  26  by spot welding or otherwise securing the pair of flaps  114  of each side wall  26  to the first  22  and second  24  end walls in the orientations shown in FIG.  1 . With the assembled relative positions of the base end walls  22 ,  24  and the base side walls  26  shown in FIG. 1, the bottom flanges  94 , the arcuate strips  102  and the L-shaped tabs  112  of each side wall project into the interior  116  of the base and the bottom flanges  74  of the second end wall  24  also project into the interior  116  of the base. The interior  116  of the base is accessible through a top opening  118  of the base as well as through a bottom opening  122  of the base. The dimensions. of the first end wall  22  leave an opening slot  124  adjacent its bottom edge  36  that enables the insertion of a filter element in a rectangular frame (not shown) through the slot  124  between the bottom flanges  94  and the arcuate strips  102  of the side walls as well as on to the bottom flanges  74  of the second end wall  24  which securely hold the filter frame in place. 
     FIGS. 9 through 11 show the construction of a louver  126  of the damper mechanism  16  of the invention. FIG. 9 shows the louver  126  as a flat blank formed from sheet metal or plastic. The louver  126  has opposite, straight side edges  128  and opposite end edges  132 . Each end edge  132  is formed with a projecting rectangular tab  134  with opposite side foldable margins  136  and a generally arcuate projecting tab  138 . One of the end edges  132 , the left side end edge as shown in FIG. 9, is also provided with a projecting flange  142  having a hole  144  passing therethrough. The louver is also provided with a pair of fold lines  146 ,  148  that extend across its length and separate the rectangular projecting tabs from their side edge margins  136 . In forming the louver  126  into its final configuration shown in FIGS. 10 and 11, the louver is folded along the pair of fold lines  146 ,  148  in the manner shown in FIG.  11  and the side edge margins  136  of the pair of rectangular projecting tabs  134  are folded over on the tabs also as shown in FIG.  11 . The opposite pair of arcuate projecting tabs  138  are bent at a right angle relative to the louver on one side of the louver and the louver flange  142  is bent at a right angle relative to the louver projecting from the opposite side of the louver relative to the arcuate tabs, as shown in FIG.  11 . In the preferred embodiment of the invention, four damper mechanism louvers are formed in the same manner as the louver described above and as shown in FIGS. 9 through 11. 
     FIGS. 12 and 13 show the louver actuator that is assembled to the louvers  126  of the damper mechanism  16 . The louver actuator is stamped from a flat sheet of metal in the configuration shown in FIG. 12 with an elongate bar  154  having a plurality of spaced openings  156  passing through the bar, and an actuator handle  158  projecting from the bar. 
     The louvers  126  and the louver actuator  152  of the damper mechanism  116  are assembled together and assembled into the interior  116  of the base in the manner shown in FIG.  1 . Because the base end walls  22 ,  24  and each of the louvers  126  are constructed from flat sheets of metal, they are resiliently bendable. This enables each of the louvers  126  to be bent slightly to insert the projecting tabs  134  at the opposite ends of each louver into one of the circular openings  46 ,  64  of the first end wall  22  and the second end wall  24  of the base. Each of the louvers is assembled into the base in this manner with its flange  142  projecting toward the top opening of the base. The holes  156  of the louver actuator  152  are aligned with the louver flange holes  144  and the louver actuator is pivotally connected to each of the louver flanges  142  by a pin or other similar type of mechanical fastener inserted through the aligned holes. With the damper mechanism  16  thus assembled into the base  12 , the actuator handle  158  can be moved between the opposite base side wall  26  to pivot the louvers between opened and closed positions in the base interior  116 . 
     The first face plate  12  of the air vent assembly kit is shown in FIG.  14 . Like the other component parts of the invention, the first face plate  12  is preferably stamped from a flat sheet of steel or made from wood or plastic with a rectangular border  162  and a decorative lattice  164  in the interior of the border. In the stamping of the first face plate  12 , preferably the interior of the rectangular face plate surrounding the lattice  164  is flat and portions of the face plate around the border  162  angle slightly downward from the top surface of the face plate. The lattice  164  is defined by a plurality of openings  166  stamped in the face plate. The face plate border  162  is also formed with four rectangular projecting tabs  168  that extend inwardly from the border  162  into four of the lattice openings  166 . The projections or tabs  168  are connected to the face plate border  162  by fold lines  172 . Each of the tabs has an oblong opening  174  passing through the tab. In the final construction of the first face plate  12 , each of the tabs or projections  168  is bent downwardly across its fold line  172  so that the tabs project perpendicularly below the face plate  12 . 
     The first face plate  12  with its decorative lattice  164  is designed to be used in the air vent assembly of the invention when the base  14  is assembled with the damper mechanism  16  and is to be used in an air outlet opening of an HVAC system. Moving the damper mechanism  16  between its opened and closed positions controls the flow of air through the air outlet opening of the HVAC system into which the air vent assembly has been inserted. The first face plate  12  is assembled to the base  14  by first positioning it over the top opening  118  of the base with each of the four face plate tabs or projections  168  positioned over one of the L-shaped tabs or projections  112  of the base. Pressing the first face plate  12  downward on top of the base  14  will result in the face plate tabs or projections  168  resiliently flexing inwardly toward each other as they pass over the L-shaped tabs or projections  112  of the base. The first face plate  12  is pressed downwardly until the L-shape projections or tabs  112  of the base pass into the openings  174  of the face plate tabs  168 . The first face plate  12  is then moved to the right as viewed in FIG. 1 until the circular projections  108  on the interior of the base side walls  26  are positioned at the sides of each of the face plate tabs  168  and securely hold the tabs against movement on the L-shaped projections  112  of the base. In this manner the first face plate  12  is attached to the base  14  without separate fasteners. The first face plate  12  can be easily removed from the base  14  by reversing the steps described above. 
     The second face plate  18  of the air vent assembly is shown in FIG.  15 . The second face plate  18  is also stamped from a flat sheet of metal with a rectangular border  182  that is substantially the same size of the border as the first face plate  12 . In addition, the second face plate border  182  is stamped so that it angles downwardly from the top surface of the second face plate in the same manner as the border of the first face plate. The interior area  184  of the second face plate is flat and has a plurality of louvers or vanes  186  formed by cuts having widened, generally U-shapes  188  made in the face plate. Fold lines  192  extend across each of the U-shaped cuts  188  and the louvers or vanes  186  are pressed downwardly below the top surface of the second face plate  18  across the fold lines  192 . As seen in FIG. 15, each of the vanes or louvers  186  are formed in the second face plate  18  in two groups that project toward each other. An outer most pair of the vanes  186  have arcuate tabs  194  cut into the vanes. The tabs  194  are bent downwardly from their respective vanes  186  along fold lines  196 . FIG. 19 shows the relative positions of the second face plate  18 , one of the folded vanes  186  and the arcuate tab  194  folded outwardly from the vane. 
     The second face plate  18  is assembled to the base  14  in a similar manner to that of the first face plate  12  except that the damper mechanism  16  is not previously assembled into the base. The second face plate  18  is positioned over the base top opening  118  with the arcuate tab projections  194  positioned above the oblong openings  44 ,  62  in the respective first  22  and second  24  base end walls. The second base plate  18  is then pressed downwardly on the base top opening  118  causing the projecting arcuate tabs  194  to pass into the base interior  116  and engage in the oblong openings  44 ,  62  in the respective opposite base end walls  22 ,  24 . In this manner, the second face plate  18  is attached to the base without separate fasteners. Because the second face plate  18  does not have the larger lattice openings  166  of the first face plate  12  that provide access to the louver actuator handle  158 , the damper mechanism  16  is not used when the second face plate  18  is used in combination with the base  14 . The second face plate  18  is intended to be used when the air vent assembly kit comprising the second face plate  18  and the base  14  are employed in covering an air return or air inlet opening of an HVAC system. 
     FIGS. 20 and 21 show a frame  200  that is part of a further embodiment of the air vent assembly of the invention. FIGS. 22-25 show a modified base  202  that is similar to the base of the previously described embodiment and is employed with the frame  200  of the further embodiment of the invention. FIGS. 26 and 27 illustrate the manner in which the frame  200  and base  202  are assembled with a face plate of the first described embodiment of the invention. The additional embodiment of the invention to be described can be used with either of the face plates  12 ,  18  of the previously described embodiment and can also be used with the damper mechanism  16  of the previously described embodiment. Therefore, the constructions of the face plates and damper mechanism will not be described again. Although the first face plate  12  is shown in FIGS. 26 and 27 being assembled with the frame  200  and base  202  of the additional embodiment of the invention, it should be understood that both face plates  12 ,  18  are equally well suited for use with the additional embodiment. It is preferred that each of the component parts of the additional embodiment of the air vent assembly be constructed of plastic for its light weight which reduces shipping costs and its resiliency which enables the component parts to be assembled together without the use of separate fasteners as will be explained. However, the component parts of the additional embodiment of the invention may be constructed of other materials. 
     The frame  200  is constructed in a rectangular configuration defined by two opposite end walls  204 ,  208  and two opposite side walls  206 ,  210  of the frame. Each of the end walls and side walls is positioned parallel to each other and are interconnected giving the frame its rectangular box shape shown in FIG.  20 . The end walls and side walls surround a hollow interior volume  212  of the frame. A pair of protrusions or abutments  214  project from one of the end walls  204  into the interior volume  212  of the frame and a single protrusion or abutment  216  protrudes from the opposite end wall  28  into the interior volume  212  of the frame. The protrusions are employed in releasably attaching the base  202  to the frame  200  in the frame interior  212  without separate fasteners as will be explained. The frame also includes a flange  218  that extends around the periphery of the frame end walls and side walls and projects outwardly from the end walls and side walls as seen in FIGS. 20 and 21. A pair of fastener holes  220  pass through portions of the flange  218  at opposite ends of the frame. 
     The base  202  has a similar rectangular configuration as the base  14  of the first described embodiment that is defined by the opposite end walls  222 ,  224  and side walls  226 ,  228  of the base. Like the first described embodiment of the base, the base  202  is provided with oblong holes  230  in one of its end walls, a shoulder surface  232  around its interior periphery for stacking or nesting purposes, and a bottom flange  234  with a slot  236  for receiving a filter assembly that is supported on the bottom flange  234  in the same manner as the first described embodiment. Opposing pairs of pawls  238  project inwardly from opposite side walls of the base for releasably attaching one of the face plates to the base. The base  202  differs from the base  14  of the first described embodiment in that it is provided with the pair of oblong holes  230  in only one of its end walls  222  with there being no corresponding oblong holes in the end wall  224  of the slot  236 , and that it does not include damper mechanism holes. The base  202  shown in FIGS. 22-25 is designed for use without a damper mechanism. However, the base end walls  222 ,  224  could easily be modified with damper holes such as those  64  of the first described embodiment in order to adapt the base  202  for use with a damper mechanism. In addition, the end wall  222  above the slot  236  is provided with a resilient tab  240  that is formed by a pair of slots  242  that extend downwardly through the end wall  242  from its top edge. The resiliency of the material of the base gives the tab  240  its resiliency. The tab has a knurled surface  244  at its top to facilitate manual deflection of the tab, and an abutment formed by an opening  246  through the tab. 
     The assembly and use of this further embodiment of the air vent assembly is shown in FIGS. 26 and 27. In assembling the air vent assembly to an air duct opening, the frame  200  is first positioned with its end walls and side walls  204 ,  206 ,  208 ,  210  extending into a rectangular air duct opening and its flange  218  resting on a surface adjacent the periphery of the air duct opening. The frame  200  is then secured to the surface surrounding the air duct opening by inserting threaded fasteners, for example wood screws, through the flange fastener holes  220  and securing the fasteners down to securely hold the frame to the air duct opening. 
     The base  202  with an inserted filter (not shown) is next inserted into the interior volume  212  of the frame. The base  202  can be empty if a damper mechanism for the air duct opening is not required, or can be previously assembled with a damper mechanism in a similar manner to that of the first described embodiment. The base  202  is inserted into the frame interior volume  212  by first inserting the base end wall  222  with the pair of oblong holes  230  into the interior volume so that the pair of protrusions or abutments  214  of the one frame end wall  204  will engage in the oblong holes  240 . The opposite base end wall  224  with the resilient tab  240  is then inserted into the frame interior volume  212  while manually deflecting the resilient tab inwardly by pushing on the knurled surface  244  of the tab. When the resilient tab abutment opening  246  is aligned with the single protrusion  216  of the frame the tab is released causing the protrusion  216  to engage in the abutment opening  246  of the tab and thereby securing the base to the interior  212  of the frame without the need for separate fasteners. 
     Next, one of the face plates  12 ,  14  is releasably secured to the base by pressing the face plate downwardly onto the base  208  so that the face plate projections or tabs  168  pass over the pawls  238  on the interior surface of the base. The face plate is pressed downwardly until the base pawls  238  engage in the openings  174  of the face plate tabs, thereby releasably securing the face plate to the base  202  and in turn to the frame  200 . This also allows for easy, no tools required removal of the faceplate, damper and filter housing from the wall for easy cleaning or replacement of the filter. 
     In the manner described above, the additional embodiment of the air vent assembly is secured to an air duct opening without the need for separate fasteners. 
     FIGS. 29-31 show a modification to the base  14  of the first described embodiment that enables it to be used with the frame  200  of the last described embodiment. In one of the base end walls  24 , a slot  250  is cut downwardly from the top edge of the end wall. A resilient tab assembly  252  constructed of plastic is inserted into the end wall slot  250 . Like the resilient tab  240  of the last described embodiment, the tab assembly  252  has a tab  254  at its center with a pair of downwardly extending slots  256  at opposite sides of the tab  254 . The slots  256  separate the tab from a pair of upwardly extending arms  258  positioned outside of the slots. The arms  258  have grooves  260  formed in their outer edges. The grooves  260  also include bottom groove portions  262  that extend below the arms  258 , the slots  256  and portions of the tab  254 . The grooves  260 ,  262  are dimensioned with widths that receive portions of the base end wall  24  in the grooves when positioning the resilient tab assembly  252  in the end wall slot  250  as shown in FIG.  31 . The insertion of the resilient tab assembly  252  into the end wall slot  250  of the first described base  14  adapts this base for use with the frame  200 . The tab  254  is provided with an abutment opening  262  and a knurled surface  266  just as the previously described tab. The modified base shown in FIGS. 29 and 31 is releasably assembled into the interior volume  212  of the frame  200  in the same manner as the last described embodiment of the invention. In addition, use of the modified base shown in FIGS. 29 and 31 enables a base containing a damper mechanism  16  to be releasably assembled into the frame  200  with one of the face plates  12 ,  14  being releasably attached to the base. 
     Should it be desired to simply attach one of the face plates  12 ,  14  over an air duct opening without the use either embodiments of the base or the frame, the fastener assembly  270  shown in FIGS. 32 and 33 may be employed to avoid the unsightly appearance of fastener heads on the exterior surface of the face plate. This also allows for easy, no tools required removal of the faceplate, damper and filter housing from the wall for easy cleaning or replacement of the filter. The face plates  12 ,  14  are modified by providing at least a pair of fastener holes at opposite ends of the face plate. The fastener assembly  270  is inserted into the fastener holes and is screwed down to attach the face plate to a surface surrounding the air duct opening. 
     The fastener assembly  270  is basically comprised of a shank portion  272  and a head portion  274 . The shank portion  272  is constructed with external wood screw threads  276  at its bottom that extend along a substantial portion of the length of the shank portion. The top of the shank portion has internal machine screw threads  278  that extend downwardly through the interior of the shank portion. The very top of the shank portion is provided with a straight screwdriver slot  280 , although a Phillips screwdriver slot could also be provided. 
     The head portion  274  of the fastener assembly has an external machine threaded shank  282  that mates with the internal machine threads of the shank portion. A screw head  284  is provided at the top of the external threaded shank  282 . The head  284  is provided with a knurled edge  288  to facilitate manual turning of the head  284  and a rounded, smooth top surface  288 . 
     In use of the fastener assembly  270  in attaching a face plate with fastener holes over an air duct opening, the face plate is first positioned over the air duct opening. One of the shank portions  272  of the fastener assembly is then screwed into the surface surrounding the air duct opening through each fastener hole of the face plate. A screwdriver is inserted into the slot  280  at the top of the shank portion  272  to assist in driving the shank portion into the material surrounding the air duct opening. When the slot  280  is substantially flush with the exterior surface of the face plate, the head portion  274  is then attached to the shank portion  272  by screw threading the external machine threaded shank  282  of each head portion into the internal machine screw threading  278  of the shank portion. The head portion  274  is tightened down on the shank portion  272  to thereby secure the face plate over the air duct opening. The smooth top surface  288  of the screw head  284  provides a more aesthetically pleasing appearance on the external surface of the face plate than would the head of a conventional wood screw. 
     Thus, the air vent assembly kit of the invention described above provides a base that can be assembled to either an air outlet opening or an air inlet opening of an HVAC system and interchangeable first and second face plates that can be attached to the base whether covering an air inlet opening or an air outlet opening of the HVAC system. The damper mechanism  16  of the kit can be selectively assembled to the base or left out of the base as desired. Furthermore, because the base end walls and side walls are constructed with lower sections that are spaced inwardly toward each other, a plurality of bases can be nested together and stacked in a compact arrangement for shipping or storage. The damper mechanism  16  and the face plates  12 ,  18  can also be packaged substantially flat for compact shipping or storing. Still further, by stamped each of the component parts from sheet metal the air vent assembly kit of the present invention is inexpensively manufactured. 
     While the present invention has been described by reference to specific embodiments, it should be understood that modifications and variations of the invention may be constructed without departing from the scope of the invention defined in the following claims.