Abstract:
A fan is provided incorporating one or more fan blades adapted to move in a back-and-forth sweeping motion about a generally horizontal axis in order to generate air flow both laterally and vertically. Fan blades with large surface areas may be used to generate the desired volumes of air movement.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of and priority to U.S. Provisional Application No. 61/268,730, filed on Jun. 15, 2009, the contents of which are fully incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to electric ceiling fans, and more particularly, to a fan with a fan blade that moves in a back-and-forth sweeping motion about a generally horizontal axis. 
         [0003]    Ceiling fans typically have a motor mounted within a housing that is suspended from a ceiling. A plurality of fan blades, typically made out of a rigid material such as wood or hard plastic, extend horizontally from the main housing and are attached to the motor&#39;s drive shaft which is oriented vertically. In operation, the motor rotates the blades in a continuous 360 degree rotation around the vertically-oriented motor drive shaft, which causes air to be drawn in a generally downward direction. 
         [0004]    Although variations on the basic ceiling fan design have been developed, including blade shape designs, motor housing designs and covers, the basic design of a plurality of horizontally extending fan blades from a main housing and adapted to rotate about a substantially vertical axis has remained unchanged. Specifically, variations in fan blade design have been developed to provide greater downward airflow or greater lateral airflow than traditional designs. However, most of these designs include horizontally extending blades adapted to rotate about a substantially vertical axis. 
         [0005]    Accordingly, it is seen that a need exists for an improved fan that moves relatively large amounts of air both laterally and vertically, and which does not require fast spinning blades rotating about a substantially vertical axis. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with the present invention, a fan is provided incorporating one or more fan blades adapted to move in a back-and-forth sweeping motion about a generally horizontal axis in order to generate air flow both laterally and vertically. Fan blades with large surface areas may be used to generate the desired volumes of air movement. 
         [0007]    In one exemplary embodiment, a fan is provided having a motor, a drive wheel coupled to and rotatable by a motor drive shaft of the motor, at least one fan blade coupled to the drive wheel, wherein each fan blade is pivotable about a generally horizontal axis, and wherein the generally horizontal axis is offset from the rotational axis of the motor drive shaft. In another exemplary embodiment, the fan blade is flexible. In a further exemplary embodiment, the fan blade is flexible and contains a plurality of flexible stiffening rods. In yet another exemplary embodiment, the fan blade is flexible and trapezoidal-shaped and contains a plurality of flexible stiffening rods and a plurality of sleeves housing the plurality of flexible stiffening rods. In another exemplary embodiment, the fan blade is flexible and rectangular-shaped and contains a plurality of flexible stiffening rods and a plurality of sleeves housing the plurality of flexible stiffening rods. In another exemplary embodiment, the fan blade has a minimum surface area of approximately 4,500 square inches. In yet another exemplary embodiment, the fan blade is adapted to baffle sound. In another exemplary embodiment, one or more ceiling support members are connected to the motor. The ceiling support members may be hollow. 
         [0008]    In another exemplary embodiment, a fan is provided having a motor, a drive wheel coupled to and rotatable by a motor drive shaft of the motor, wherein the drive wheel is coupled to the motor drive shaft about a first point, at least one fan blade coupled to the drive wheel by at least one drive rod pivotally connected to at least one bell crank, wherein the drive rod is connected to the drive wheel about a second point, the drive rod is connected to the bell crank about a third point, the bell crank is pivotally connected to an axle about a fourth point, each fan blade is pivotable about a generally horizontal axis, and wherein the generally horizontal axis is offset from the rotational axis of the motor drive shaft. 
         [0009]    In a further exemplary embodiment, the radius of the drive wheel, as measured from the first point to the second point, is less than the length of the bell crank, as measured from the third point to the fourth point. In another exemplary embodiment, the fan blade is flexible. In a further exemplary embodiment, the fan blade is flexible and contains a plurality of flexible stiffening rods. In yet another exemplary embodiment, the fan blade is flexible and trapezoidal-shaped and contains a plurality of flexible stiffening rods and a plurality of sleeves housing the plurality of flexible stiffening rods. In another exemplary embodiment, the fan blade is flexible and rectangular-shaped and contains a plurality of flexible stiffening rods and a plurality of sleeves housing the plurality of flexible stiffening rods. In another exemplary embodiment, the fan blade has a minimum surface area of approximately 4,500 square inches. In yet another exemplary embodiment, the fan blade is adapted to baffle sound. In another exemplary embodiment, one or more ceiling support members are connected to the motor, wherein said ceiling support members are hollow. 
         [0010]    In another exemplary embodiment, a method for cooling a room includes providing a fan having a fan blade, displacing at least 50,000 cubic feet of air per minute, consuming a maximum of approximately 50 watts of electricity, and wherein displacing the air comprises pivoting the fan blade about a generally horizontal axis, by an electric motor. In another exemplary embodiment, the fan blade is flexible. In a further exemplary embodiment, the fan blade is flexible and contains a plurality of flexible stiffening rods. In yet another exemplary embodiment, the fan blade is flexible and trapezoidal-shaped and contains a plurality of flexible stiffening rods and a plurality of sleeves housing the plurality of flexible stiffening rods. In another exemplary embodiment, the fan blade is flexible and rectangular-shaped and contains a plurality of flexible stiffening rods and a plurality of sleeves housing the plurality of flexible stiffening rods. In another exemplary embodiment, the fan blade has a minimum surface area of approximately 4,500 square inches. In yet another exemplary embodiment, the fan blade is adapted to baffle sound. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of the fan according to a first exemplary embodiment showing a trapezoidal-shaped fan blade  21 . 
           [0012]      FIG. 2  is a perspective view of a portion of the fan according to a first exemplary embodiment. 
           [0013]      FIG. 3  is a perspective view of the fan according to a second exemplary embodiment. 
           [0014]      FIG. 4  is an exploded view of the parts employed in the first exemplary embodiment of the fan. 
           [0015]      FIG. 5  is a view of a geared motor  30 , a motor mount flange  25 , five isolation bolts  26 ,  27 ,  28 ,  29 , and  33 , and a motor drive shaft  22 . 
           [0016]      FIG. 6  is a detail view of the motor mount flange  25 , the drive shaft  22 , and a rod end bearing journals  6 ,  18 ,  19 ,  20 . 
           [0017]      FIG. 7  is a perspective view of the fan according to a third exemplary embodiment. 
           [0018]      FIG. 8  is a perspective view of the fan according to a fourth exemplary embodiment. 
           [0019]      FIG. 9  is a detail view of a trapezoidal-shaped fan blade  21 , a rod support terminal  13 , two horizontal rods  31  and  32 , and two rods  14  and  15 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    With reference to  FIGS. 1 ,  2 ,  4 ,  5 ,  6 , and  9 , a fan according to a first exemplary embodiment of the invention will first be described. In  FIGS. 1 ,  2 ,  4 , and  9 , identical reference numerals are used for representing constituent elements of the fan of the first exemplary embodiment. 
         [0021]      FIG. 1  is a perspective view showing the fan in the first exemplary embodiment.  FIG. 1  shows a trapezoidal-shaped fan blade  21  formed from a flexible material, e.g., a fabric, and supported by two horizontal rods  31  and  32 , and supported by two rods  14  and  15 , oriented obliquely relative to a rod support terminal ( 13  in  FIGS. 2 and 9 ). In other exemplary embodiments, the fan blade  21  may be formed from a rigid material, e.g., wood or metal. In the first exemplary embodiment, the two horizontal rods  31  and  32 , and the two rods  14  and  15 , are formed from a flexible material, e.g., plastic, wood, metal, or composite. The fan blade  21 , especially if formed from a flexible material, may contain sleeves used to house the two horizontal rods  31  and  32 , and the two rods,  14  and  15 . The sleeves may be formed with the same material as the fan blade  21 . The two horizontal rods  31  and  32 , connected to and extending outward from the rod support terminal ( 13  in  FIGS. 2 and 9 ) form a horizontal hanging support for the fan blade  21 . The two rods  14  and  15 , are attached to the rod support terminal ( 13  in  FIGS. 2 and 9 ) and are slipped into the sleeves in the fan blade  21 .  FIG. 9  shows a detail view of the trapezoidal-shaped fan blade  21 , the rod support terminal  13 , the two horizontal rods  31  and  32 , and the two rods  14  and  15 , according to the first exemplary embodiment. 
         [0022]      FIG. 2  is a perspective view showing a portion of the fan in the first exemplary embodiment. Shown in  FIG. 2 , a fan having a motor housing  3  is suspended from a ceiling by two ceiling support members  16  and  17 . In other exemplary embodiments, one or more ceiling support members may be used. In the first exemplary embodiment, two fan hanger mounting flanges ( 34  and  35  in  FIG. 4 ) are welded to the motor housing  3  and are adapted to receive and are connected to the two ceiling support members  16  and  17 . 
         [0023]    With continued reference to  FIG. 2 , in this exemplary embodiment, a 12-volt or 24-volt DC planetary geared motor ( 30  in  FIG. 5 ), or other low voltage motor, is mounted within the motor housing  3  and connected to a power source by wires that extend through the fan hanger mounting flanges ( 34  and  35  in  FIG. 4 ) and the two ceiling support members  16  and  17 . A motor drive shaft ( 22  in  FIGS. 2 and 5 ) attached to the geared motor ( 30  in  FIG. 5 ) rotatably drives a drive wheel  2  in a 360-degree rotation cycle. In this exemplary embodiment, the motor mounting flange ( 25  in  FIG. 5 ) is attached to a main support arm  1  with five (5) isolation bolts ( 26 ,  27 ,  28 ,  29 , and  33  in  FIGS. 5 and 6 ). Opposite sides of the motor housing  3  are connected to the main support arm  1  and a back plate ( 4  in  FIG. 4 ), respectively. 
         [0024]    As the drive wheel  2  rotates through the 360-degree rotation cycle it pushes and pulls a drive rod  7  which is pivotally connected to the drive wheel  2 . The drive rod  7  is coupled to a second drive rod  8  by a bell crank  5  which is pivotally attached to the main support arm  1  by means of an axle  38  rotatably supported by a flanged ball bearing ( 39  in  FIGS. 2 and 4 ) attached to the main support arm  1 . As the first drive rod  7  is pushed and pulled by the rotating drive wheel  2 , the first drive rod  7  pivotally drives the bell crank  5  which pushes and pulls the second drive rod  8  synchronously with the first drive rod  7 . The first drive rod  7  and the second drive rod  8  are attached to opposite end portions of the bell crank  5 . Opposite ends of the first drive rod  7  are connected to the bell crank  5  and the drive wheel  2  by two rod end bearing journals,  6  and  18 , respectively. Opposite ends of the second drive rod  8  are connected to the bell crank  5  and the drive lever  12  by two rod end bearing journals,  19  and  20 , respectively. In this exemplary embodiment, the radius of the drive wheel  2 , as measured from the drive shaft  22  attachment point on the drive wheel  2  to the rod end bearing journal  18  attachment point on the drive wheel  2 , is shorter than the length of the bell crank  5 , as measured from the rod end bearing journal  6  attachment point on the bell crank  5  to the axle  38  attachment point on the bell crank  5 , so as to cause the drive rod  7  to pivotally drive the bell crank  5  in a back-and-forth motion. 
         [0025]    As the second drive rod  8  is pushed and pulled, the second drive rod  8  pivotally drives an axle drive lever  12  back-and-forth about a generally horizontal axis ( 40 ). The axle drive lever  12  is fixed to an axle  9  which is pivotable about the generally horizontal axis ( 40 ) and is supported by two flanged ball bearings,  23  and  37 , which are attached to the back plate  4  and the main support arm  1 , respectively. The axle  9  is connected to two axle arms,  10  and  11 , and the two axle arms,  10  and  11 , are connected to the rod support terminal  13 . The axle  9 , the two axle arms  10  and  11 , and the rod support terminal  13  pivot back-and-forth about the generally horizontal axis ( 40 ) synchronously with the axle drive lever  12 . The two axle arms,  10  and  11 , fixed to the axle  9  and fixed to the rod support terminal  13  pivotally drive the fan blade  21  in a back-and-forth sweeping motion about the generally horizontal axis ( 40 ). The fan blade  21  is supported by the two horizontal rods,  31  and  32 , extending outward from and connected to opposite ends of the rod support terminal  13  and is supported by the two rods,  14  and  15 , oriented obliquely relative to the rod support terminal ( 13  in  FIGS. 2 and 9 ). 
         [0026]    Applicant has apprehended that this exemplary embodiment of the fan cools a room by providing an electric motor which consumes a maximum of approximately 50 watts of electricity while rotating a fan blade with a minimum surface area of approximately 4,500 square inches about a generally horizontal axis and displacing more than 50,000 cubic feet of air per minute, e.g., 55,000 cubic feet per minute. The applicant has also apprehended the large surface area of the fan blade in this exemplary embodiment acts as a sound baffle to mitigate echoes in large rooms. 
         [0027]      FIG. 3  is a perspective view showing the fan in a second exemplary embodiment.  FIG. 3  shows a fan which is essentially the same as the first exemplary embodiment described in reference to  FIG. 2  except for the shape of the fan blade  36 .  FIG. 3  shows a rectangular-shaped fan blade  36  formed from a flexible material, e.g. a fabric, and supported by a horizontal rod (H) and seven ( 7 ) support rods (A), (B), (C), (D), (E), (F), and (G), oriented at approximately 90 degrees relative to the horizontal rod (H). In other exemplary embodiments, the fan blade  36  may be formed from a rigid material, e.g., wood or metal. In the second exemplary embodiment, the horizontal rod (H) and the seven support rods (A), (B), (C), (D), (E), (F), and (G), may be formed from a flexible material, e.g., plastic, wood, metal, or composite. The fan blade  36 , especially if formed from a flexible material, may contain sleeves used to house the horizontal rod (H) and the seven support rods (A), (B), (C), (D), (E), (F), and (G). The sleeves may be formed with the same material as the fan blade  36 . 
         [0028]    With reference to  FIGS. 4 ,  5 , and  7 , a third exemplary embodiment will be described.  FIG. 7  is a perspective view showing the fan in the third exemplary embodiment. A fan having a motor housing  103  is suspended from a ceiling by two ceiling support members,  116  and  117 . In other exemplary embodiments, one or more ceiling support members may be used. In the third exemplary embodiment, two fan hanger mounting flanges ( 34  and  35  in  FIG. 4 ) are welded to the motor housing  103  and are adapted to receive and are attached to the two ceiling support members,  116  and  117 . 
         [0029]    A 12-volt or 24-volt DC planetary geared motor ( 30  in  FIG. 5 ), or other low voltage motor, is mounted within the motor housing  103  and connected to a power source in the ceiling by wires that extend through the fan hanger mounting flanges ( 34  and  35  in  FIG. 4 ) and the two ceiling support members,  116  and  117 . A motor drive shaft  122  which is attached to the geared motor ( 30  in  FIG. 5 ) rotatably drives a drive wheel  102  in a 360-degree rotation cycle. In this exemplary embodiment, a motor mounting flange ( 25  in  FIG. 5 ) is attached to a first main support arm  101  with five (5) isolation bolts, ( 26 ,  27 ,  28 ,  29 , and  33  in  FIG. 5 ). Opposite sides of the motor housing  103  are connected to a first main support arm  101  and a second main support arm  114 , respectively. As the drive wheel  102  rotates through the 360-degree rotation cycle it pushes and pulls a drive rod  107  pivotally connected to the drive wheel  102 . Opposite ends of the drive rod  107  are pivotally connected to a bell crank  105  and the drive wheel  102  by rod end bearing journals,  106  and  118 , respectively. As the drive rod  107  is pushed and pulled by the rotating drive wheel  102 , the drive rod  107  pivotally drives the bell crank  105  in a back-and-forth motion about a generally horizontal axis ( 138 ). The bell crank  105  is fixed to an axle  109  which is pivotable about the generally horizontal axis ( 138 ) and is supported by two flanged ball bearings,  137  and  123 , which are attached to the first main support arm  101  and the second main support arm  114 , respectively. In this exemplary embodiment, the radius of the drive wheel  102 , as measured from the drive shaft  122  attachment point on the drive wheel  102  to the rod end bearing journal  118  attachment point on the drive wheel  102 , is shorter than the length of the bell crank  105 , as measured from the rod end bearing journal  106  attachment point on the bell crank  105  to the axle  109  attachment point on the bell crank  105 , so as to cause the drive rod  107  to pivotally drive the bell crank  105  in a back-and-forth motion about the generally horizontal axis ( 138 ). 
         [0030]    With continued reference to  FIG. 7 , the axle  109  is connected to two axle arms,  110  and  111 , and the two axle arms,  110  and  111 , are connected to a rod support terminal  113 . The axle  109 , the two axle arms,  110  and  111 , and the rod support terminal  113  all pivot back-and-forth about the generally horizontal axis ( 138 ) synchronously with the bell crank  105 . The axle  109  is pivotally supported by two flanged ball bearings,  137  and  123 , which are connected to the first main support arm  101  and the second main support arm  114 , respectively. The axle  109 , connected to the two axle arms,  110  and  111 , and connected to the rod support terminal  113 , pivotally drive a fan blade  121  formed from a flexible material, e.g., a fabric, in a back-and-forth sweeping motion about the generally horizontal axis ( 138 ). In other exemplary embodiments, the fan blade  121  may be formed from a rigid material, e.g., wood or metal. In the third exemplary embodiment, a set of two horizontal rods,  131  and  132 , extending outward from and connected to opposite ends of the rod support terminal  113  form a horizontal hanging support for the fan blade  121 . The two horizontal rods,  131  and  132 , are formed from a flexible material, e.g., plastic, wood, metal, or composite. In other exemplary embodiments, one or more rods may be connected to the fan blade  121  and used to support the fan blade  121 . 
         [0031]      FIG. 8  is a perspective view showing the fan in a fourth exemplary embodiment. Here, the fan in the fourth exemplary embodiment is similar to the third exemplary embodiment described in reference to  FIG. 7  except that the fan includes a second fan blade  247  opposite a first fan blade  221  and includes the support structure necessary to pivotally drive the second fan blade  247  in a back-and-forth sweeping motion. In the fourth exemplary embodiment, both the first fan blade  221  and the second fan blade  247  are formed from a flexible material, e.g., a fabric. In other exemplary embodiments, the first fan blade  221  and the second fan blade  247  may be formed from a rigid material, e.g., wood or metal. According to the fourth exemplary embodiment,  FIG. 8  shows the support structure necessary to pivotally drive the second fan blade  247 , which includes a third main support arm  240 , a fourth main support arm  241 , a second drive rod  208 , a second bell crank  242 , a second axle  243 , a second rod support terminal  246 , and a second set of two axle arms,  244  and  245 . The support structure necessary to pivotally drive the second fan blade  247  in the fourth exemplary embodiment is oriented and connected in a manner similar to that described in the third exemplary embodiment. The assemblage of the structure necessary to rotatably drive the second fan blade  247  in the fourth exemplary embodiment is a mirror image of the structure shown in  FIG. 7  in reference to the third exemplary embodiment. 
         [0032]    With continued reference to  FIG. 8 , a fan having a motor housing  203  is suspended from a ceiling by two ceiling support members,  216  and  217 . In other exemplary embodiments, one or more ceiling support members may be used. In the fourth exemplary embodiment, two fan hanger mounting flanges ( 34  and  35  in  FIG. 4 ) are welded to the motor housing  203  and are adapted to receive and are attached to the two ceiling support members,  216  and  217 . Opposite sides of the motor housing  203  are connected to a first and the third main support arm,  201  and  240 , and a second and the fourth main support arm,  214  and  241 , respectively. 
         [0033]    In this exemplary embodiment, a 12-volt or 24-volt DC planetary geared motor ( 30  in  FIG. 5 ), or other low voltage motor, is mounted within the motor housing  203  and connected to a power source by wires that extend through the fan hanger mounting flanges ( 34  and  35  in  FIG. 4 ) and the two ceiling support members,  216  and  217 . A motor drive shaft  222  which is attached to the geared motor ( 30  in  FIG. 5 ) rotatably drives a drive wheel  202  in a 360-degree rotation cycle. The drive wheel  202  is connected to a first drive rod  207  and the second drive rod  208 . As the drive wheel  202  rotates through the 360-degree rotation cycle it synchronously pushes and pulls the first drive rod  207  and the second drive rod  208 . Opposite ends of the first drive rod  207  are pivotally connected to a first bell crank  205  and the drive wheel  202  by two rod end bearing journals,  206  and  218 , respectively. As the first drive rod  207  is pushed and pulled by the rotating drive wheel  202 , the first drive rod  207  pivotally drives the first bell crank  205  in a back-and-forth motion about a first generally horizontal axis ( 238 ). Opposite ends of the second drive rod  208  are pivotally connected to a second bell crank  242  and the drive wheel  202  by two rod end bearing journals,  220  and  219 , respectively. As the second drive rod  208  is pushed and pulled by the rotating drive wheel  202 , the second drive rod  208  pivotally drives the second bell crank  242  in a back-and-forth motion about a second generally horizontal axis ( 252 ). 
         [0034]    The first bell crank  205  is connected to a first axle  209  which is pivotable about the first generally horizontal axis ( 238 ) and is supported by two flanged ball bearings,  237  and  223 , which are connected to a first main support arm  201  and a second main support arm  214 , respectively. The second bell crank  242  is connected to a second axle  243 , which is rotatable about the second generally horizontal axis ( 252 ) and is supported by two flanged ball bearings,  251  and  250 , which are connected to the third main support arm  240  and the fourth main support arm  241 , respectively. In this exemplary embodiment, the radius of the drive wheel  202 , as measured from the drive shaft  222  attachment point on the drive wheel  202  to the rod end bearing journal  218  attachment point on the drive wheel  202 , is shorter than the length of the first bell crank  205 , as measured from the rod end bearing journal  206  attachment point on the first bell crank  205  to the axle  209  attachment point on the first bell crank  205 , and is shorter than the length of the second bell crank  242 , as measured from the rod end bearing journal  220  attachment point on the second bell crank  242  to the axle  243  attachment point on the second bell crank  242 , so as to cause the first drive rod  207  to pivotally drive the first bell crank  205  in a back-and-forth motion about the first generally horizontal axis  238  and so as to cause the second drive rod  208  to pivotally drive the second bell crank  242  in a back-and-forth motion about the second generally horizontal axis  252 . 
         [0035]    The first and second axle,  209  and  243 , are connected to a first set of two axle arms,  210  and  211 , and a second set of two axle arms,  244  and  245 , respectively. The first set of two axle arms,  210  and  211 , are connected to a first rod support terminal  213  and the second set of two axle arms,  244  and  245 , are connected to a second rod support terminal  246 . The first and second axle,  209  and  243 , the first set of two axle arms,  210  and  211 , the second set of two axle arms,  244  and  245 , and the first and second rod support terminal,  213  and  246 , all pivot synchronously with the rotation of the drive wheel  202 . 
         [0036]    The first set of two axle arms,  210  and  211 , fixed to the first axle  209  and fixed to the first rod support terminal  213  pivotally drive the first fan blade  221  in a back-and-forth sweeping motion about the first generally horizontal axis ( 238 ). The second set of two axle arms,  244  and  245 , fixed to the second axle  243  and fixed to the second rod support terminal  246  pivotally drive the second fan blade  247  in a back-and-forth sweeping motion about the second generally horizontal axis ( 252 ). The first and second fan blades  221  and  247  are supported by a first set of two horizontal rods,  231  and  232 , and a second set of two horizontal rods,  248  and  249 , respectively. The first set of two horizontal rods,  231  and  232 , and the second set of two horizontal rods,  248  and  249 , extend outward from and are connected to opposite ends of the first and second rod support terminals,  213  and  246 , respectively. The first set of two horizontal rods,  231  and  232 , and the second set of two horizontal rods,  248  and  248 , are formed from a flexible material, e.g., plastic, wood, metal, or composite. In other exemplary embodiments, one or more rods may be connected to the first fan blade  221  and the second fan blade  247  and used to support the first fan blade  221  and the second fan blade  247 . 
         [0037]    While this invention has been described in detail with particular references to the exemplary embodiments thereof, it will be understood by those skilled in the art that variations, additions and deletions, are contemplated within the scope of this invention. The exemplary embodiments described herein are not intended to be exhaustive or to limit the scope of the invention to the exact forms disclosed.