Patent Publication Number: US-2007122286-A1

Title: Novel fan blade of a ceiling fan

Description:
FIELD OF THE UTILITY MODEL  
      The present invention relates to a ceiling fan, in particular to a novel fan blade of the ceiling fan.  
     BACKGROUND OF UTILITY MODEL  
      A conventional ceiling fan, especially decorative ceiling fan, has 4-6 fan blades, each blade structure comprises a fan blade and a mounting bracket to which one end of the fan blade is locked to a motor; if necessary, the fan blade may be directly mounted to the motor, without use of the mounted bracket. In general, each of the fan blades may be made from wood plates, plywood or fiberboard by means of the woodworking machines. The perimeter of thus processed fan blade is substantially perpendicular to two sides surfaces of the fan blade except for being chamfered in ordinary processing. Such a processing method is still used up to now.  
      To save energy, the inventor analyzed and studied the traditional fan blades. The results showed that the resistance of such a traditional fan blade relative to the relative wind is higher and is increased with increasing of the power of the ceiling fan and the thickness of the fan blade. To achieve the aim of saving the energy, some novel blades must be designed to decrease the air resistance of the fan blades.  
     SUMMARY OF THE UTILITY MODEL  
      It is an object of the present invention to provide a novel fan blade of a ceiling fan. Such a blade not only can decrease the air resistance but also save the energy significantly. Furthermore, the appearance of the blades is embellished. In addition, the production technique of the traditional fan blades can be kept unchanged.  
      The novel fan blade according to the present invention which comprises (1) A fan blade; and (2) A mounting bracket to which one end of the fan blade is mounted and by which the fan blade is locked to a motor; if necessary, the fan blade may be directly mounted to the motor, characterized in that whole or partial perimeter of the fan blade is made in an outwardly projecting shape. For example, as seen from the cross section of the fan blade, perimeter of the fan blade can be presented in a shape of circular arc, oval, taper with circular arc, obliquity with circular arc, truncated taper, truncated oblique or taper with circular arc in which two sides of the projecting base have a raised bench.  
      As whole or partial perimeter of the fan blade according the present invention is designed to project outwardly, firstly, its weight is reduced compared to the traditional fan blades. Secondly, the air resistance is decreased. Thirdly, the appearance of the fan blade is embellished. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention will be better understood from the following detailed description of the preferred embodiments, when taken in connection the accompanying drawings, in which:  
       FIG. 1  shows a side view of a commercially available decorative ceiling fan;  
       FIG. 2  shows a top view of a fan blade of commercially available decorative ceiling fan;  
       FIG. 3  shows a perspective view of a mounting bracket by which the fan blade is locked to a motor of a ceiling fan;  
       FIG. 4  shows a transverse sectional view of the fan blade taken on line A 1 -A 1  of  FIG.2 ;  
       FIG. 5  shows a transverse sectional view of the outwardly projecting perimeter of the fan blade in the circular arc shape according to the present invention;  
       FIG. 6  shows a transverse sectional view of the outwardly projecting perimeter of the fan blade in the shape of taper with arc according to the present invention;  
       FIG. 7  shows a transverse sectional view of the outwardly projecting perimeter of the fan blade in the shape of obliquity with circular arc according to the present invention;  
       FIG. 8  shows a transverse sectional view of the outwardly projecting perimeter of the fan blade in the truncated taper shape according to the present invention;  
       FIG. 9  shows a transverse sectional view of the outwardly projecting perimeter of the fan blade in the truncated oblique shape according to the present invention; and  
       FIG. 10  shows a transverse sectional view of the outwardly projecting perimeter of the fan blade in the shape of taper with circular arc in which two sides of projecting base have a raised bench according to the present invention. 
    
    
     EXAMPLES  
      Referring to  FIG. 1 , a commercially available decorative ceiling fan is shown, including the fan blade  10 , a mounting bracket  12  to which the fan blade is mounted and a motor  14 . The mounting bracket  12  is mounted to the motor  14 . As shown in  FIG. 2 , there are the through holes at one end of the fan blade  10  for connecting the mounting bracket  12  in a manner of riveting. Referring to  FIG. 3 , the mounting bracket  12  is provided with a plurality of holes in response to the through holes of the fan blade and the holes on the motor so that the fan blade  10  is mounted to the mounting bracket  12  and then to the motor  14 .  
      The commercially available decorative ceiling fan blades are simple plate structure, which has been used for long time. As shown in  FIG. 4 , outer of the fan blade perimeter basically is perpendicular to two sides of the fan blade, and the corner thereof is required to be chamfered according to technical requirements during processing. However, such chamfer is not able to attain the same effect as that produced by the fan blade according to the present invention.  
      In the traditional production technique of the fan blades, the technique includes the following steps, if they are constructed of fiberboard from 3 mm to 6 mm thickness: 
      1. Sticking a wood grain paper of over both sides of the fiberboard;     2. Making rough cutting according to the required fan blade shape;     3. Carrying out edge milling of cutting edges;     4. Drilling through holes at one end of the fan blade;     5. Base-coating, edge sealing, lacquering the milled edges; and     6. Balance Weighting, matching and packing (for 5 ceiling fan blades, the weight difference thereamong must be less than 2 g)    

      The fan blades of the present invention can be manufactured using the above technique. However, in the step 3, carrying out edge milling needs to use some special milling cutters with different shapes in response to the different outwardly projecting perimeters of the fan blades.  
      For example, the cross section of the outwardly projecting perimeter of the fan blade  101  in accordance with the present invention can be formed into the circular arc shape by means of milling cutter in the circular arc shape, as shown in  FIG. 5 , wherein the radius of the circular arc (R 1 ) is 1.0-5.0 mm. Similarly, the cross section of the outwardly projecting perimeter of the fan blade  102  can be formed into the shape of taper with circular arc or oval shape by means of milling cutter with corresponding shape, as shown in  FIG. 6 , wherein the radius of the circular arc (R 2 ) is 1-5 mm, and the taper angle (α 1 )is 10-60 degree, preferably 25 degree. The cross section of the outwardly projecting perimeter of the fan blade  103  can be formed into the shape of obliquity with circular arc by means of milling cutter with corresponding shape, as shown in  FIG. 7 , wherein the radius of the circular arc (R 3 ) is 1-5 mm, the obliquity (α 2 ) is 10-60 degree, preferably 25 degree. The cross section of the outwardly projecting perimeter of the fan blade  104  can be made into truncated taper shape by means of milling cutter with corresponding shape, as shown in  FIG. 8 , wherein the taper angle (α 3 ) is 10-60 degree, preferably 25 degree, the truncated width (W 1 ) is 1-5 mm, preferably 3 mm. The cross section of the outwardly projecting perimeter of the fan blade  105  can be made into truncated oblique shape by means of milling cutter with corresponding shape, as shown in  FIG. 9 , wherein the obliquity (α 4 ) is 10-60 degree, preferably 25 degree, the truncated width (W 2 ) is 1-5 mm, preferably 3 mm. The cross section of the outwardly projecting perimeter of the fan blade  106  can be formed into the shape of taper with circular arc by means of milling cutter with corresponding shape, as shown in  FIG. 10 , wherein the radius of the circular arc (R 4 ) is 1-5 mm, the taper angle (α 5 ) is 10-60 degree, preferably 25 degree; while two sides of the projecting base have a raised bench (d), the height of which is 0.01-2 mm, preferably 0.05 mm.  
      The fan blades, of course, can also be made of wood plates, plywood, decorative fiberboard or other complex wooden board or plastic or other resin materials. The production techniques of fan blades from wood plates, plywood, decorative fiberboard or other complex wooden board are the same as that described above, for except the plastic fan blades. The fan blades are made from the plastic or resin material by injection molding technique in the art, wherein the different shapes of the outwardly projecting perimeter of the fan blades depend on the different shapes of the corresponding moulds.  
      Lastly, a comparison test between the ceiling fans with the fan blades according to the present invention (group A) and with the traditional fan blades (group B) at the same conditions.  
      The comparison test results show that: 
      1. The ceiling fan (group A) may increase the rotational speed which is 15-24% greater than that of the traditional ceiling fan (group B); and     2. The ceiling fan (group A) may have an increased air volume which is 5-10% greater than that of the traditional ceiling fan (group B).    

      The above comparison test results is enough to prove that, to achieve rotational speed and air volume of the traditional ceiling fan, the ceiling fan employing the fan blades in accordance with the present invention may select a lower power motor so that consumption of energy and/or raw materials can be reduced.  
      Although above preferred embodiment have been described in great detail, for those skilled in the art, changes and modifications may be made without departing the general design idea and the present inventive concept. Such changes and modifications shall fall within the scope of the present invention.