Abstract:
Ceiling fan blades for maximizing air flow at operational speeds of up to approximately 200 revolutions per minute(rpm). The blades have a positive twist at the tip ends of approximately 5 degrees to approximately 10 degrees parallel to the ceiling. The root end of the blades closest to the motor can have a positive twist exceeding that of the tip end and can be approximately 20 to approximately 35 degrees parallel to the ceiling. The ceiling fans can have individual blade lengths of approximately 20 inches and overall spans of up to approximately 52 inches and up to approximately 54 inches. Each embodiment can use three, four, and five blades, with the blades being made of injection molded plastic. and the like. The embodiments can include built in light kit domes.

Description:
This invention relates to ceiling fans, and in particular to ceiling fan blades with twisted bodies for providing increased airflow at low rotational speeds with low energy consumption, and claims the benefit of Provisional Application No. 60/265,241 filed Jan. 31, 2001 and is a continuation-in-part of U.S. Ser. No. 09/711,599 filed Nov. 13, 2000, which is a divisional application of U.S. Ser. No. 09/415,883 filed Oct. 8, 1999 now U.S. Pat. No. 6,189,799, which is a divisional application of U.S. Ser. No. 09/067,236 filed Apr. 27, 1998 now U.S. Pat. No. 5,996,898 which is incorporated by reference, which is a continuation-in-part of U.S. Ser. No. 09/056,428 filed Apr. 7, 1998 now U.S. Pat. No. 6,039,541 which is incorporated by reference. 
    
    
     BACKGROUND AND PRIOR ART 
     Ceiling fans have been around for many years as a useful air circulator. The popular blade style over the years is a flat planar rectangular blade that can have a slight tilt, as shown for example in U.S. Pat. No. Des. 355,027 to Young and U.S. Pat. No. Des. 382,636 to Yang. These patents while moving air are not concerned with maximizing optimum downward airflow. Furthermore, many of the flat ceiling fan blades have problems such as vibrations and wobbling during use, and excessive noise that is noticeable to persons in the vicinity of the fan blades. 
     Aircraft, marine and automobile engine propeller type blades have been altered over the years to shapes other than flat rectangular. See for example, U.S. Pat. No. 1,903,823 to Lougheed; U.S. Pat. No. 1,942,688 to Davis; U.S. Pat. No. 2,283,956 to Smith; U.S. Pat. No. 2,345,047 to Houghton; U.S. Pat. No. 2,450,440 to Mills; U.S. Pat. No. 4,197,057 to Hayashi; U.S. Pat. No. 4,325,675 to Gallot et al.; U.S. Pat. No. 4,411,598 to Okada; U.S. Pat. No. 4,416,434 to Thibert; U.S. Pat. No. 4,730,985 to Rothman et al. U.S. Pat. No. 4,794,633 to Hickey; 4.844,698 to Gornstein; U.S. Pat. No. 5,114,313 to Vorus; and U.S. Pat. No. 5,253,979 to Fradenburgh et al.; Australian Patent 19,987 to Eather. However, these patents are describing devices that are generally used for high speed water, aircraft, and automobile applications where the propellers are run at high revolutions per minute(rpm) generally in excess of 500 rpm. None of these propellers are designed for optimum airflow at low speeds of less than approximately 200 rpm which is the desired speeds used in overhead ceiling fan systems. 
     Some alternative blade shapes have been proposed for other types of fans. See for example, U.S. Pat. No. 1,506,937 to Miller; U.S. Pat. No. 2,682,925 to Wosik; U.S. Pat. No. 4,892,460 to Volk; U.S. Pat. No. 5,244,349 to Wang; Great Britain Patent 676,406 to Spencer; and PCT Application No. WO 92/07192. 
     Miller &#39;937 requires that their blades have root “lips 26” FIG. 1 that overlap one another, and would not be practical nor useable for three or more fan blade operation for a ceiling fan. Wosik &#39;925 describes “fan blades . . . particularly adapted to fan blades on top of cooling towers such for example as are used in oil refineries and in other industries”, column 1, lines 1-5, and does not describe any use for ceiling fan applications. The Volk &#39;460 patent by claiming to be “aerodynamically designed” requires one curved piece to be attached at one end to a conventional planar rectangular blade. Using two pieces for each blade adds extreme costs in both the manufacturing and assembly of the ceiling itself. Furthermore, the grooved connection point in the Volk devices would appear to be susceptible to separating and causing a hazard to anyone or any property beneath the ceiling fan itself. Such an added device also has necessarily less than optimal aerodynamic properties. 
     Wang &#39;349 requires each of their blades be “drilled with a plurality of perforations . . . for reducing weight . . . (and) may be reinforced by at least one rib . . . ”, abstract. Clearly, such a blades would not be aesthetically pleasing to the user to have various holes and ribs visible on the blades, and there is no description for increasing airflow with such an arrangement. Great Britain Patent &#39;406 describes “fan impellers” that require an “a unitary structure . . . constituted by a boss and four blades” page 1, lines 38+, and does not describe any single blades that can be used without any central boss type hub arrangement nor any use for less than three or more than four blade operation that will allow versatility for mounting separate numbers of blades on a ceiling fan motor. PCT &#39;192 is for use “in an electric fan . . . to convert axially existing ambient air into a radially outward current of air”, abstract, and is shown in FIGS. 5-12 as being used for being mounted on “post(s)”, and the like, and is not directed toward a ceiling fan operation, which would direct air primarily downward. Additionally, PCT &#39;192 generally requires an elaborate arrangement of using plural blades angled both upward and downward for operation. 
     Thus, the need exists for solutions to the above described problems in the prior art. 
     SUMMARY OF THE INVENTION 
     The first objective of the subject invention is to provide ceiling fan blades that are aerodynamically optimized to move up to approximately 40% or more air than traditional flat planar ceiling fan blades. 
     The second objective of the subject invention is to provide ceiling fan blades that are quieter and provide greater comfort than traditional flat planar ceiling fan blades. 
     The third objective of the subject invention is to provide ceiling fan blades that are less prone to wobble than traditional flat planar ceiling fan blades. 
     The fourth objective of the subject invention is to provide ceiling fan blades that reduce electrical power consumption and are more energy efficient over traditional flat planar ceiling fan blades. 
     The fifth objective of the subject invention is to provide ceiling fan blades designed for superior airflow at up to approximately 200 revolutions per minute(rpm). 
     The sixth objective of the subject invention is to provide ceiling fan blades being more aesthetically appealing than traditional flat planar ceiling fan blades. 
     Three embodiments of a novel ceiling fan blade are described where each blade can include a tip end having a twist of approximately 5 degrees to approximately 10 degrees, and a root end attached to a ceiling fan motor, wherein the positive twist provides increased air flow over other ceiling fan blades. The root end can include a twist of approximately 20 to approximately 35 degrees. The blades generally include a concave raised bottom and a convex shaped upper surface. The blades are mounted to motor assemblies in a twisted configuration. The blades can be mounted to a ceiling fan motor and provide enhanced airflow at speeds of up to approximately 200 revolutions per minute(rpm). The novel ceiling fan system includes wingspans of up to approximately 52 inches and up to approximately 54 inches. 
    
    
     Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated schematically in the accompanying drawings. 
     BRIEF DESCRIPTION OF THE FIGURES 
     FIG. 1 is a perspective view of a first embodiment of the novel blades with motor assembly. 
     FIG. 2 is a side view of the first embodiment of FIG.  1 . 
     FIG. 3 is a top view of the first embodiment of FIG. 2 along arrow A 1 . 
     FIG. 4A is a perspective view of a single fan blade of the first embodiment of FIGS. 1-3. 
     FIG. 4B is an end view of the single fan blade of FIG. 4A representing degrees of twist between from the root end to the tip end. 
     FIG. 4C is a cross-sectional view of the tip end of the first embodiment of FIGS. 4A-4B. 
     FIG. 4D is a cross-sectional view of the root end of the first embodiment of FIGS. 4A-4B. 
     FIG. 5 is a top view of a ceiling fan blade of the first embodiment of FIGS. 1-4D. 
     FIG. 6 is a side view of the ceiling fan blade of FIG. 5 along arrow A 2 . 
     FIG. 7 is an end view of the ceiling fan blade of FIG. 6 along arrow A 3 . 
     FIG. 8 is a perspective view of a second embodiment of the novel blades with motor assembly. 
     FIG. 9 is a side view of the second embodiment of FIG.  8 . 
     FIG. 10 is a top view of the second embodiment of FIG. 9 along arrow B 1 . 
     FIG. 11A is a perspective view of a single fan blade of the second embodiment of FIGS. 8-10. 
     FIG. 11B is an end view of the single fan blade of FIG. 11A representing degrees of twist between from the root end to the tip end. 
     FIG. 11C is cross-sectional view of the tip end of the second embodiment of FIGS. 11A-11B. 
     FIG. 11D is a cross-sectional view of the root end of the second embodiment of FIGS. 11A-11B. 
     FIG. 12 is a top view of a ceiling fan blade of the second embodiment of FIGS. 11A-11D. 
     FIG. 13 is a side view of the ceiling fan blade of FIG. 12 along arrow B 2 . 
     FIG. 14 is an end view of the ceiling fan blade of FIG. 13 along arrow B 3 . 
     FIG. 15A is a perspective view of a single fan blade of a third embodiment of invention. 
     FIG. 15B is an end view of the single fan blade of FIG. 15A representing degrees of twist between from the root end to the tip end. 
     FIG. 15C is cross-sectional view of the tip end of the third embodiment of FIGS. 15A-15B. 
     FIG. 15D is a cross-sectional view of the root end of the third embodiment of FIGS. 15A-15B. 
     FIG. 16 is a top view of a ceiling fan blade of the third embodiment of FIGS. 15A-15D. 
     FIG. 17 is a side view of the ceiling fan blade of FIG. 16 along arrow C 1 . 
     FIG. 18 is an end view of the ceiling fan blade of FIG. 17 along arrow C 2 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before explaining the disclosed embodiments of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation. 
     Testing of novel ceiling fan blades in the parent patent application to the subject invention, namely U.S. Pat. Ser. No. 09/056,428 filed Apr. 7, 1998, now U.S. Pat. No. 6,039,541, and incorporated by reference, were tested between May and June, 1997 at the Florida Solar Energy Center® in Cocoa, Florida, and included three parameters of measurement data: airflow(meters per second(m/s), power(in watts) and speed(revolutions per minute(rpm)). Those novel ceiling fan blades far surpassed the operating parameters of various conventional ceiling fans in operation, and the subject fan blades have similar attributes. 
     FIRST EMBODIMENT 
     FIG. 1 is a perspective view of a first embodiment  100  of a first embodiment of the novel twisted blades  110 . twisted mounting arm  130  conventionally mounted to motor assembly  120 , light kit dome  125 , such as a incandescent bulb, and the like, and ceiling mount  128 . FIG. 2 is a side view of the first embodiment  100  of FIG.  1 . FIG. 3 is a top view of the first embodiment  100  of FIG. 2 along arrow A 1 . 
     FIG. 4A is a perspective view of a single fan blade  110  of the first embodiment  100  of FIGS. 1-3, showing the single fan blade  110  having an overall length D 1 , between tip end  100 TE and root end  100 RE being approximately 19.50 inches, and various reference cross-sections( 100 TE,  100 RS( 4 ),  100 RE) being approximately 3.90 inches from one another along the airfoil center line  100 ACL, and blade  110  having leading edge  100 LE and trailing edge  100 TEDGE oriented along the blade rotational plane RP. FIG. 4B is an end view of the single fan blade  110  of FIG. 4A representing degrees of twist between from the root end  100 RE to the tip end  100 TE, when the blade  110  is positioned in a selected position shown in FIGS.  1 - 3 (Note the twisted mounting arm  130  of FIG. 1 is used to hold the twist position shown in FIG.  4 B). The tip end  100 TE has an angle of approximately 6.22 degrees from a horizontal plane that is parallel to a ceiling. In other words, the angle would be approximately 6.22 degrees from the motor axis(MA)(being the rotational axis of the blades. The root end  100 RE would have an angle of twist of approximately 25.63 degrees(19.41+6.22). The mid cross-sectional areas noted as  100 RS have varying angles of twist between the tip end  100 TE and the root end  200 RE. 
     FIG. 4C is a cross-sectional view of the tip end  100  TE of the first embodiment  100  of FIGS. 4A-4B. Referring to FIG. 4C, tip end  100 TE has a width span of approximately 4.223 inches. The rounded leading edge  100 TELE has a diameter of approximately 0.080 degrees being approximately 0.298 inches thick and approximately 0.5 inches from rounded leading edge  100 TELE. The middle of tip end  100  TE has a thickness of approximately 0.227 inches (0.374−0.147), with a generally concave shaped elongated bottom section raised approximately 0.147 inches and upper surface being generally convex shaped. Rounded tip end trailing edge  100 TETE has a diameter of approximately 0.085 degrees with a thickness of approximately 0.238 inches approximately 0.5 inches from the rounded trailing edge  100 TETE. 
     FIG. 4D is a cross-sectional view of the root end  100  RE of the first embodiment  100  of FIGS. 4A-4B. Referring to FIG. 4D, root end  100 RE has a width span of approximately 6.122 inches. The rounded leading edge  100 RELE has a diameter of approximately 0.110 degrees being approximately 0.430 inches thick approximately 0.5 inches from rounded leading edge  100 RELE. The middle of root end  100  RE has a thickness of approximately 0.317(0.544−0.227) inches, with a generally concave shaped elongated bottom section raised midway approximately 0.227 inches and upper surface being generally convex shaped. Rounded tip end trailing edge  100 RETE has a diameter of approximately 0.118 degrees with a thickness of approximately 0.331 inches approximately 0.5 inches from the rounded trailing edge  100 RETE. 
     FIG. 5 is a top view of a ceiling fan blade  110  of the first embodiment  100  of FIGS. 1-4D, where the length, L 1  can be approximately 19.5 inches to approximately 20.228 inches from tip end  100 TE to root end  200  RE. FIG. 6 is a side view of the ceiling fan blade  110  of FIG. 5 along arrow A 2 . FIG. 7 is an end view of the ceiling fan blade  110  of FIG. 6 along arrow A 3 . 
     SECOND EMBODIMENT 
     FIG. 8 is a perspective view of a second embodiment  200  of the novel blades  210  attached to a mounting ring  230  which rotates relative to conventional motor assembly  220 . A dome shaped light  225  can also be used. 
     FIG. 9 is a side view of the second embodiment  200  of FIG.  8 . FIG. 10 is a top view of the second embodiment  200  of FIG. 9 along arrow B 1 . 
     FIG. 11A is a perspective view of a single fan blade  210  of the second embodiment  200  of FIGS. 8-10 showing the single fan blade  210  having an overall length D 2  between tip end  200 TE and root end  200 RE being approximately 20 inches, and various reference cross-sections( 200 TE,  200 RS( 4 ),  200 RE) being approximately 4 inches from one another along air foil center line  200 ACL, and blade  210  having leading edge  200 LE and trailing edge  200 TEDGE oriented along the blade rotational plane RP. FIG. 11B is an end view of the single fan blade  210  of FIG. 11A representing degrees of twist between from the root end  200 RE to the tip end  200 TE when the blade  210  is positioned in a selected position shown in FIGS. 8-10. The tip end  200  TE has an angle of approximately 6.30 degrees from a horizontal plane that is parallel to the ceiling. In other words, the angle would be approximately 6.3 degrees from a motor axis(MA). The root end  200 RE would have an angle of twist of approximately 27.17 degrees(6.3+20.87). The mid cross-sectional areas noted as  200 RS have varying angles of twist between the tip end  200 TE and the root end  200 RE. 
     FIG. 11C is cross-sectional view of the tip end  200 TE of the second embodiment  200  of FIGS. 11A-11B. Referring to FIG. 11C, tip end  200 TE has a width span of approximately 3.524 inches. The rounded leading edge  200 TELE has a diameter of approximately 0.062 degrees being approximately 0.257 inches thick approximately 0.5 inches from leading edge  200 TELE. The middle of tip end  200 TE has a thickness of approximately 0.181 inches(0.314−0.133), with a generally concave shaped elongated bottom section raised approximately 0.133 inches and an upper surface being generally convex shaped. Rounded tip end trailing edge  200 TETE has a diameter of approximately 0.070 inches with a thickness of approximately 0.190 inches approximately 0.5 inches from the rounded trailing edge  200 TETE. 
     FIG. 11D is a cross-sectional view of the root end  200 RE of the second embodiment  200  of FIGS. 11A-11B. Referring to FIG. 11D, root end  200 RE has a width span of approximately 5.151 inches. The rounded leading edge  200 RELE has a diameter of approximately 0.090 degrees being approximately 0.365 inches thick approximately 0.5 inches from rounded leading edge  200 RELE. The middle of root end  200 RE has a thickness of approximately 0.265 inches(0.455−0.190), with a generally concave shaped elongated bottom section raised midway approximately 0.190 inches and an upper surface being generally convex shaped. Rounded tip end trailing edge  200 RETE has a diameter of approximately 0.103 degrees with a thickness of approximately 0.279 inches approximately 0.5 inches from rounded trailing edge  200 RETE. 
     FIG. 12 is a top view of a ceiling fan blade  210  of the second embodiment  200  of FIGS. 11A-11D, where the length L 2  can be approximately 20 inches to approximately 20.819 inches long from tip end  200 TE to root end  200 RE. FIG. 13 is a side view of the ceiling fan blade  210  of FIG. 12 along arrow B 2 . FIG. 14 is an end view of the ceiling fan blade  210  of FIG. 13 along arrow B 3 . 
     Subject invention second embodiment had an overall wing span of approximately  52 ″, and used fan blades each being made of injection molded plastic. 
     Table 1 shows running the second embodiment of the subject invention at low speed operations, with the Power Drawer is the instantaneous electric power requirement in Watts. The parameters include power(in watts) and speed(revolutions per minute(rpm)). 
     
       
         
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 FAN (LOW SPEED OPERATION) 
               
             
          
           
               
                   
                 Power 
                 Revolutions 
               
               
                   
                 Draw 
                 Per Minute 
               
               
                   
                   
               
             
          
           
               
                   
                 Invention 2 nd  Embodiment 
                 17.9 Watts 
                 81 rpm 
               
               
                   
                   
               
             
          
         
       
     
     Table 2 shows running the second embodiment of the subject invention at medium speed operations, with the Power Drawer is the instantaneous electric power requirement in Watts. 
     
       
         
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 FAN (MEDIUM SPEED OPERATION) 
               
             
          
           
               
                   
                 Power 
                 Revolutions 
               
               
                   
                 Draw 
                 Per Minute 
               
               
                   
                   
               
             
          
           
               
                   
                 Invention 2 nd  Embodiment 
                 38.6 Watts 
                 135 rpm 
               
               
                   
                   
               
             
          
         
       
     
     Table 3 shows running the second embodiment of the subject invention at high speed operations, with the Power Drawer is the instantaneous electric power requirement in Watts. 
     
       
         
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 FAN (HIGH SPEED OPERATION) 
               
             
          
           
               
                   
                 Power 
                 Revolutions 
               
               
                   
                 Draw 
                 Per Minute 
               
               
                   
                   
               
             
          
           
               
                   
                 Invention 2 nd  Embodiment 
                 62.3 Watts 
                 176 rpm 
               
               
                   
                   
               
             
          
         
       
     
     THIRD EMBODIMENT 
     FIG. 15A is a perspective view of a single fan blade  310  of a third embodiment  300  of invention showing the single fan blade  310  having an overall length D 3  between tip end  300 TE and root end  300 RE being approximately 23.5 inches, and various reference cross-sections( 300 RS( 4 ),  300 RE) being approximately 4.70 inches from one another along air foil center line  300 ACL, and blade  310  having leading edge  300 LE and trailing edge  300 TEDGE oriented along the blade rotational plane RP. FIG. 15B is an end view of the single fan blade  310  of FIG. 15A representing degrees of twist between from the root end  300 RE to the tip end  300 TE, when the blade is positioned in a selected position on a ceiling fan motor assembly like those shown in the previous embodiments. The tip end  300 TE has an angle of approximately 4.71 degrees from a horizontal plane that is parallel to the ceiling. In other words, the angle would be approximately 4.71 degrees from a motor axis(MA). The root end  200 RE would have an angle of twist of approximately 30.76 degrees(4.71+26.05). The mid cross-sectional areas noted as  300 RS have varying degrees of twist between the tip end  300 TE and the root end  300 RE. 
     FIG. 15C is cross-sectional view of the tip end  300 TE of the third embodiment  300  of FIGS. 15A-15B. Referring to FIG. 15C, tip end  300 TE has a width span of approximately 2.990 inches. The rounded leading edge  300 TELE has a diameter of approximately 0.052 degrees being approximately 0.210 inches thick approximately 0.5 inches from the leading edge  300 TELE. The middle of tip end  300 TE has a thickness of approximately 0.049 inches(0.138−0.089), with a generally concave shaped elongated bottom section raised approximately 0.089 inches and upper surface being generally convex shaped. Rounded tip end trailing edge  300 TETE has a diameter of approximately 0.049 inches approximately 0.5 inches from rounded trailing edge  300 TETE. 
     FIG. 15D is a cross-sectional view of the root end  300 RE of the third embodiment  300  of FIGS. 15A-15B. Referring to FIG. 15D, root end  300 RE has a width span of approximately 5.594 inches. The rounded leading edge  300 RELE has a diameter of approximately 0.086 degrees being approximately 0.396 inches thick approximately 0.5 inches from leading edge  300 RELE. The middle of root end  300 RE has a thickness of approximately 0.268 inches(0.438−0.170), with a generally concave shaped elongated bottom section raised midway approximately 0.170 inches, and an upper surface being generally convex shaped. Rounded tip end trailing edge  300 RETE can have a blunt, and/or rounded tip with a thickness of approximately 0.068 inches approximately 0.5 inches from the trailing edge  300 RETE. 
     FIG. 16 is a top view of a ceiling fan blade  310  of the third embodiment  300  of FIGS. 15A-15D, having a length L 3  of approximately 23.5 inches to approximately 24.5 inches between the root end  300 RE and the tip end  300 TE. FIG. 17 is a side view of the ceiling fan blade  310  of FIG. 16 along arrow C 1 . FIG. 18 is an end view of the ceiling fan blade  310  of FIG. 17 along arrow C 2 . 
     The subject invention allows for maximizing air flow for ceiling fans having wing spans of up to approximately 52 and approximately 54 inches, with the blades shaped to maximize downward air flow at RPMs of up to approximately 200RPM. 
     While the invention has been described. disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.