Window Fan

Abstract

A dual window fan having a rectangular body adapted to engage a window, two fan heads pivotably engaging the body independently of each other about a vertical pivot axis from aiming directly outwardly normal to the body to aiming inwardly through a pivot angle of at least 225 angular degrees.

I claim: 
     
         1 . A window fan comprising:
 a rectangular body adapted to engage a window within an opening thereof;   a plurality of fan heads pivotably engaging the body independently of each other each adapted to cause airflow through the body either inwardly when pivoted inwardly and outwardly when pivoted outwardly.   
     
     
         2 . The window fan of  claim 1  wherein the fan heads are each pivotable relative to the body about a vertical pivot axis. 
     
     
         3 . The window fan of  claim 2  wherein the fan heads are each pivotable from aiming directly outwardly normal to the body to aiming inwardly through a pivot angle of at least 225 angular degrees. 
     
     
         4 . The window fan of  claim 3  wherein each fan head comprises a non-reversible motor coupled to a fan blade and adapted to rotate the fan blade only in a single rotational direction to cause an airflow through the associated fan head only in one axial direction relative to the associated fan head. 
     
     
         5 . The window fan of  claim 4  wherein each fan head comprises intake and exhaust openings and each fan blade comprises fan vanes shaped with a concave downwind face and convex upwind face for optimal airflow from the intake opening to the exhaust opening. 
     
     
         6 . The window fan of  claim 5  wherein each fan head comprises spirally-curved intake and exhaust vanes and cylindrical duct surrounding its associated fan blade, the intake and exhaust vanes curved in the single rotational direction, such that the rotating fan blade, duct, and vanes cooperate to cause helical collimation of the airflow. 
     
     
         7 . The window fan of  claim 6  wherein each fan blade comprises five equally-spaced fan blade vanes. 
     
     
         8 . The window fan of  claim 7  further comprising expandible side panels adapted for extension from the body to cover any portion of the opening that the body does not. 
     
     
         9 . The window fam of  FIG. 8  further comprising bug screens adapted for selective affixation to the body over the intake opening of each fan head and dome shaped to allow pivoting of the fan head. 
     
     
         10 . The window fan of  claim 1  wherein the fan heads are each pivotable from aiming directly outwardly normal to the body to aiming inwardly through a pivot angle of at least 225 angular degrees. 
     
     
         11 . The window fan of  claim 10  wherein each fan head comprises a non-reversible motor coupled to a fan blade and adapted to rotate the fan blade only in a single rotational direction to cause an airflow through the associated fan head only in one axial direction relative to the associated fan head. 
     
     
         12 . The window fan of  claim 11  wherein each fan head comprises intake and exhaust openings and each fan blade comprises fan vanes shaped with a concave downwind face and convex upwind face for optimal airflow from the intake opening to the exhaust opening. 
     
     
         13 . The window fan of  claim 12  wherein each fan head comprises spirally-curved intake and exhaust vanes and cylindrical duct surrounding its associated fan blade, the vanes curved in the single rotational direction, such that the rotating fan blade, duct, and vanes cooperate to cause helical collimation of the airflow. 
     
     
         14 . The window fan of  claim 13  wherein each fan blade comprises five equally-spaced fan blade vanes. 
     
     
         15 . The window fan of  claim 14  further comprising expandible side panels adapted for extension from the body to cover any portion of the opening that the body does not. 
     
     
         16 . The window fam of  FIG. 15  further comprising bug screens adapted for selective affixation to the body over the intake opening of each fan head and dome shaped to allow pivoting of the fan head. 
     
     
         17 . The window fan of  claim 1  wherein each fan head comprises intake and exhaust openings and each fan blade comprises fan vanes shaped with a concave downwind face and convex upwind face for optimal airflow from the intake opening to the exhaust opening. 
     
     
         18 . The window fan of  claim 17  wherein each fan head comprises spirally-curved intake and exhaust vanes and cylindrical duct surrounding its associated fan blade, the vanes curved in the single rotational direction, such that the rotating fan blade, duct, and vanes cooperate to cause helical collimation of the airflow. 
     
     
         19 . The window fan of  claim 18  wherein each fan blade comprises five equally-spaced fan blade vanes. 
     
     
         20 . The window fan of  claim 19  further comprising expandible side panels adapted for extension from the body to cover any portion of the opening that the body does not. 
     
     
         21 . The window fam of  FIG. 20  further comprising bug screens adapted for selective affixation to the body over the intake opening of each fan head and dome shaped to allow pivoting of the fan head.