Abstract:
A foundation vent comprising a front frame and resiliently-flexible clips with tabs at their ends. The foundation vent can be quickly installed within a foundation opening by flexing the clips, placing them into the opening, and pushing the front frame until it seats against the exterior of a foundation wall. At this point, the tabs of the clips will have protruded past the interior face of the foundation wall allowing the clips to return to their unflexed state and causing the tabs to secure against the interior face of the foundation wall.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
   None 
   FEDERALLY SPONSORED RESEARCH 
   No 
   BACKGROUND OF THE INVENTION 
   Enclosed crawlspaces beneath buildings usually have soil floors and are contained by a concrete or masonry wall that extends down to the footings. Moisture is a concern in crawlspaces because it can create environmental conditions that are favorable for the growth of mildew, molds, and other kinds of fungi. One source of moisture in crawlspaces is the water vapor that escapes from the soil. Leaks or drainage that infiltrate the crawlspace are another common source of moisture. At certain humidity levels, the moisture in the crawlspace atmosphere will condense within the crawlspace. Standing condensate creates a nuisance and can foster the growth of unhealthy microorganisms such as  Legionella  bacteria. Condensed moisture also absorbs into porous surfaces and fosters rot that results in the deterioration of structural components such as wooden joists. Even when the moisture does not result in structural deterioration and health problems, it can lead to the creation of undesirable musty odors. 
   To reduce the humidity levels in crawlspaces to levels that discourage the condensation of moisture, it is desirable to ventilate the crawlspace. Ventilation, in addition to reducing moisture levels, serves to vent out other gases such as radon and vapors from termite treatment. To promote ventilation, it is common to provide ventilation openings in the wall or foundation surrounding the crawlspace. For example, many building codes specify that the walls surrounding crawlspaces must have ventilation openings of not less than 1 square foot for each 150 square feet of crawlspace area. 
   It is very common to cover ventilation openings with foundation vents that have a grid or bars at the exterior face to exclude debris and vermin such as mice and insects. Most foundation vents are installed in openings that measure 8 inches high by 16 inches wide, which is the space that would be occupied by a standard masonry block. Some foundation vents feature a shutter which can be closed to seal the vent during cold weather. Foundation vents with shutters come in manually-operated and automatic versions, the shutters in the automatic versions generally being opened and closed through the action of a bi-metal coil that operates without electricity. In addition, some foundation vents incorporate an electrically-powered fan to force air to vent from the crawlspace. 
   There are various ways of installing foundation vents depending on their design, A common way of installing vents is by applying a bed of cement, caulking, or other adhesive at the bottom of the opening in the foundation, setting the vent into the opening, and then securing the vent edges with a surface coat of the cement, caulking, or other adhesive. Another means of securing foundation vents is to drill holes into the foundation wall and then secure the vent with nails, screws, or wall anchors. Some foundation vents are secured to foundation openings by tabs that are either pressed against or nailed to the circumferential face of the opening. Such means of securing vents require the installer to spend time and use tools to install a vent. Vents which require the use of adhesives or the creation of holes in the foundation wall also can result in unsightly marring of the foundation. Thus, there is a need for a foundation vent that can be quickly installed without tools, adhesives, or the need to use fasteners such as screws and nails. 
   SUMMARY OF THE INVENTION 
   The present invention comprises a foundation vent that can be quickly installed without the use of tools or adhesives. The vent assembly has a front frame that engages the exterior face of the foundation wall when the assembly is pushed into the ventilation opening; a grid that serves to screen the opening, and two rear-facing clips with tabs that extend past and flexibly engage the interior face of the foundation wall to secure the vent assembly to the foundation wall. In the preferred embodiment, the front frame has slots near the edge of the right and left sides of the front frame into which the clips can be inserted prior to installation. This allows the installer to select rear-facing members of a depth appropriate for the foundation wall into which the assembly will be installed. For example, clips of differing length can be premanufactured to enable assemblies to be installed into ventilation openings in walls of standard thicknesses such as the 8-inch foundation wall commonly encountered. In addition, manufacturing the clips separately from the front frame allows the assembly to shipped in a compact dissembled state at a lower packaging and shipping cost. 
   Installation of the present invention is a straightforward process. The installer determines the thickness of the foundation wall at the ventilation opening and selects two clips of the appropriate length. Each clip has a first end that is set at a slight angle from the central reach of the clip and a second end that forms a tab set at an approximately perpendicular angle from the central reach. The first ends of the clips are inserted into slots in the front frame. A projection inside each slot engages a recess in the end of a clip and secures the clip to the frame. The installer then flexes the clips towards each other so that they fit within the ventilation opening. The assembly is pushed into the ventilation opening until the outer flange on the frame rests against the exterior face of the foundation wall. At this point, the clips will flex away from each other causing the tabs to engage against the interior face of the foundation wall and secure the vent. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of a foundation vent embodying the invention. 
       FIG. 2  is a rear perspective view of a foundation vent embodying the invention. 
       FIG. 3  is a rear view detailing one of the slots in the front frame. 
       FIG. 4A  is a side view of a clip. 
       FIG. 4B  is a side view showing another face of a clip. 
       FIG. 5  is a side cutaway view showing the foundation vent installed in a ventilation opening. 
       FIG. 6  is a front perspective view of a foundation vent embodying manually-adjustable louvers. 
       FIG. 7  is a front perspective view of a foundation vent embodying automatic louvers. 
       FIG. 8  is a front perspective view of a foundation vent embodying a fan. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   As shown in  FIGS. 1 and 2 , the preferred embodiment of the foundation vent of the present invention comprises a rectangular front frame  2  having a peripheral front flange  4  and a peripheral skirt  6 . The central portion of the front frame  2  is provided with a integral screen portion  12 . In the preferred embodiment, the integral screen portion  12  is connected to the rear portion of the skirt  6  so that a recessed space is created between the rear and front faces of the skirt which can receive a plugging member (not shown) to seal the front frame  2  during cold weather. Two clips  14  having a proximal end  36  and distal end  16  are attached to the rear face of the front frame  2  by inserting the proximal ends  36  into slots  22  located on the front frame as shown in  FIG. 2 . The distal ends  16  of the clips  14  art set at an angle that is substantially parallel to the front flange  4  and have an inner face  18  that extends beyond the edge of the peripheral skirt  6 . Holes  8  are provided at the corners of the peripheral front flange  4  so that the front flange  2  may be optionally secured to a foundation wall with screws, nails, or similar fasteners if desired. Front frame  2  can be made of any suitable material that is weather resistant and sufficiently rigid to support the front frame inside a ventilation opening. Examples of suitable materials include plastics such as polypropylene and nylon and metals such as aluminum and galvanized steel but the preferred embodiment is made of injection-molded plastic. 
     FIG. 3  shows a slot  22  set adjacent to the skirt  6 . In the preferred embodiment, two slots  22  are set into the opposed short sides of the front frame  2 . The purpose of slot  22  is to receive and retain the proximal end  36  of a clip  14  (not shown in  FIG. 3 ). The slot  22  has two small indentations  24  set along the portion of the slot adjacent to the screen portion  12 . A small protrusion  26  extends from the inner portion of the skirt  6  into the slot  22 . 
     FIG. 4A  shows the face of clip  14  that faces outwards from the front frame  2  when installed into a slot  22 . The clip  14  has a proximal end  36 , distal end  16 , and a central portion  32 . The proximal end  36  is designed to fit into a slot  22  (depicted in  FIGS. 2 and 3 ) and has a small recess  40  into which the protrusion  26  shown in  FIG. 3  snaps into place when the proximal end  36  is fully inserted to slot  22 . The proximal end also has a pair of ridges  20  that engage with the small indentations  24  (also depicted in  FIG. 3 ). The purpose of the small indentations  24  and the ridges  20  is to ensure that the clips  14  are installed so that their distal ends  16  face outwards. The proximal end has two protuberances  38  that act as stops to further limit the depth at which a clip  14  can be inserted into a slot  22 . The proximal end may be set at a slight angle to the central portion  32  so that the clip  14  splays outward slightly from the front frame  2  when the clips  14  are installed into the slots  22  (see  FIG. 2 ). The distal ends  16  are angled sharply from the central portion  32  such that the distal ends  16  are positioned substantially parallel to the front flange  2  when the proximal ends  32  are inserted into slots  22  (depicted in  FIG. 2 ). It is noted that the angle and lengths of the central portions  32  and distal ends  16  need only be sufficient to firmly secure the assembly to the wall and that considerable latitude should be given to the term substantial as used in this context (e.g., 90 degrees±20 degrees). 
     FIG. 4B  Clip shows the face of a clip  14  that faces inward when installed into the front frame  2 . Note that the ridges  20  extend longitudinally along the central portion  32  and the distal end  16  and serve the additional purpose of providing structural reinforcement to the clip  14 . 
   The clips  14  can be made of any suitable material that has a sufficient flexible resilience to withstand being flexed about 15 degrees inwards once installed into a slot  22  and has a sufficient yield strength to return to the unflexed state once the flexing force is relieved. Examples of suitable materials include plastics such as polyethylene and nylon and metals such as aluminum and galvanized steel. In the preferred embodiment, the clips are made of injection-molded plastic. Depending on the depth of the foundation wall into which the foundation vent will be installed, clips  14  can be selected of the appropriate length. To aid an installer in identifying an appropriate clip  14 , a length indicia  34  can be molded or incised on the central portion  32  as depicted in  FIG. 4A . Standard thicknesses commonly encountered in poured-concrete and masonry-block walls are 4, 6, 8, 10, and 12 inches. 
     FIG. 5  depicts a side view of the foundation vent installed into a foundation wall A having a ventilation opening B. To install the foundation vent, the distal ends  16  of the clips  14  are flexibly pushed in the direction towards each other so that the clips  14  bend at an angle of about 20 degrees away from the unflexed position, which moves the distal ends inwards a sufficient length to clear the edges of the ventilation opening B. The installer inserts the clips partway into said ventilation opening B and releases the clips  14  so that they flex back toward and make a light biased contact with the opposed short faces of the ventilation opening B. The installer then pushes the front frame  2  into the ventilation opening B until the skirt  6  is set within the ventilation opening B and the front flange  4  rests against the exterior face of the foundation wall A. At the moment when the front frame  2  seats against the exterior face of the foundation wall A, the distal ends  16  of the clips  14  will slide past the interior face of the foundation wall A and allow the clips  14  to return to their unflexed position causing the distal ends  16  to rest against the interior face of the foundation wall A and thus securing the foundation vent to the foundation wall A. 
   It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from its scope and spirit. For example, the front frame could be modified as shown in  FIG. 6  to encompass manually-operated shutters  41  or as shown in  FIG. 7  to encompass automatic shutters  42  such as the kind actuated by a bimetallic spring coil  43 . Similarly, the front frame could be modified as shown in  FIG. 8  to accept a fan  44  to provide forced ventilation of a crawlspace.  FIG. 8  also shows the plugging member  46  that can be inserted into the space bounded by the peripheral skirt  6  to seal the front frame during cold weather. In addition, the present invention could be constructed in any shape and used in other applications where it is desirable to have a screened vent installed to cover an opening within a wall. Thus, it is intended that the present invention cover the modifications and variations that come within the scope of the claims and their equivalents.