Fan,especially a ceiling fan with a balanced single blande

Abstract

The invention provides a fan ( 10 ) with a blade ( 12 ), suitable for use as a ceiling fan. Blade ( 12 ) may be regarded as a single blade, although shaft ( 18 ) is not attached to blade ( 12 ) at one end thereof; rather, shaft ( 18 ) is attached to blade ( 12 ) at a point between first end ( 14 ) and second end ( 16 ). Blade ( 12 ) is balanced by counterweight means ( 22 ) located in blade ( 12 ). In on embodiment, blade ( 12 ) is connected to shaft ( 18 ) by means which permit angular movement, such as a teeter hinge.

1 . A blade for a fan comprising: 
 a first portion having a first end;    a second portion having a second end, the second end opposed to the first end; and    at least one counterweight coupled to one of the first portion and the second portion, both the first and the second portions are adapted to provide aerodynamic lift.    
   
   
       2 . The blade of  claim 1 , wherein the first portion has a first leading edge and a first trailing edge; the second portion has a second leading edge and a second trailing edge; and the aerodynamic lift provided by the second portion at least partially balances the aerodynamic lift provided by the first portion.  
   
   
       3 . The blade of  claim 1 , further comprising a connection point located between the first end and the second end, the connection point for coupling to a shaft.  
   
   
       4 . The blade of  claim 3 , wherein the connection point is located at a junction between the first and the second portions.  
   
   
       5 . The blade of  claim 3 , wherein the center of mass approximately aligns with the connection point.  
   
   
       6 . The blade of  claim 3 , wherein the connection point is closer to the second end than the first end and at least one counterweight is located in the second portion.  
   
   
       7 . The blade of  claim 3 , wherein an angle of approximately 170 degrees between the first end and the second end, and the angle being proximate the connection point.  
   
   
       8 . The blade of  claim 3 , further comprising a variable pitch connector coupled to the connection point, the variable pitch connector permits angular movement relative to a shaft when coupled thereto.  
   
   
       9 . The blade of  claim 8 , wherein the variable pitch connector includes a teeter hinge.  
   
   
       10 . The blade of  claim 8 , wherein the variable pitch connector is located proximate to the center of mass of the blade.  
   
   
       11 . The blade of  claim 8 , further comprising a shaft coupled to the variable pitch connector, and a fan motor coupled to the shaft for rotationally driving the shaft, wherein at any given speed of rotation, the first end will rise until a position is found at which the aerodynamic, gravitational and centripetal forces acting on the blade are balanced to minimize or eliminate any bending moment on the shaft.  
   
   
       12 . The blade of  claim 11 , wherein a point on the first leading edge is constrained to rotate about the variable pitch connector in a plane in which the aerodynamic lift force of the blade on the first leading edge is acting to maintain the correct angle of attack of the blade.  
   
   
       13 . The blade of  claim 11  wherein, when viewed in plan, the axis of the variable pitch connector is perpendicular to a line drawn from the axis of rotation of the blade when balanced to the center of lift of the first portion.  
   
   
       14 . The blade of  claim 1 , wherein all of the at least one counterweights is located in the first and second portions.  
   
   
       15 . The blade of  claim 11 , wherein part of the at least one counterweight is located on the shaft.  
   
   
       16 . The blade of  claim 2 , wherein some or all of the at least one counterweight is located along the first leading edge of the blade.  
   
   
       17 . The blade of  claim 2 , wherein some of the at least one counterweight is located along the first leading edge of the first portion and some of the at least one counter weight is located along the first trailing edge of the first portion.  
   
   
       18 . The blade of  claim 11 , further comprising a mounting plate coupled to the fan motor for selectively attaching to a ceiling.  
   
   
       19 . (canceled)  
   
   
       20 . (canceled)  
   
   
       21 . A fan assembly comprising: 
 a blade comprising: 
 a first portion having a first end;  
 a second portion having a second end, the second end opposed to the first end, the blade adapted to provide aerodynamic lift when rotationally driven; and  
 a connection point located between the first end and the second end;  
   a shaft;    a variable pitch connector coupled to the connection point of the blade and to the shaft, the variable pitch connector permits angular movement relative between the shaft and the blade;    at least one counterweight coupled to either of the blade and the shaft; and    a fan motor coupled to the shaft for rotationally driving the shaft.    
   
   
       22 . The fan of  claim 21 , wherein at any given speed of rotation when driven by the motor, the first end of the first portion of the blade will rise until a position is found at which the aerodynamic, gravitational and centripetal forces acting on the blade are balanced to minimize or eliminate any bending moment on the shaft.