Patent Publication Number: US-7914260-B2

Title: Fan blade mounting system

Description:
REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part of U.S. patent application Ser. No. 11/655,393 filed Jan. 18, 2007, now U.S. Pat. No. 7,665,970. 
    
    
     TECHNICAL FIELD 
     This invention relates to a fan system for mounting blade irons, and specifically to systems for automatically balancing the blade irons and blades of a fan. 
     BACKGROUND OF THE INVENTION 
     Many different types of fans exist today, such as ceiling fans, table fans, pedestal fans, and fans used in conjunction with mechanical equipment. Most of these fans include a blade and a blade mount or blade iron which couples the blade to the motor. 
     Electrically powered ceiling fans typically have a motor mounted within a stationary housing that is suspended from a ceiling. In operation, the motor rotates an annular array of individual extensions in the form of blade mounts or blade irons. Each blade iron is associated with a blade mounted thereto. 
     The blades of ceiling fans are usually coupled to the blade irons by passing mounting screws through holes in the blade and into threaded holes in the blade iron. The blade irons are then mounted to the motor. 
     Fan blade imbalance and the associated ceiling fan wobble may result from a variety of off-balanced or imbalanced discrepancies associated with the ceiling fan blades, including variations in blade pitch angle, dihedral angle, uneven circumferential spacing between adjacent blade pairs, blade warpage and uneven radial spacing of the blades from the vertical axis of rotation. Ceiling fan wobble, and the associated vibration, creates undesirable noise, is visually distracting, and may adversely affect the service life of the ceiling fan. 
     Accordingly, it is seen that a need remains for a ceiling fan system that can be quickly and easily balance the rotating blades. It is to the provision of such therefore that the present invention is primarily directed. 
     SUMMARY OF THE INVENTION 
     In a preferred form of the invention a fan comprises an electric motor, a balancing member, and an annular array of blade irons coupled to the motor for radial movement relative to the motor. Each blade iron also has an end pivotally mounted to the flexible balancing member. The fan also includes a ceiling fan blade associated with each said blade iron of said annular array of blade irons. With this construction, an off balanced movement of a blade iron causes the radial movement of the flexible balancing member, which in turn causes the radial movement of the other blade irons towards an equilibrium position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a bottom view of a ceiling fan embodying principles of the invention in a preferred form. 
         FIG. 2  is a perspective view of a portion of the ceiling fan of  FIG. 1 . 
         FIG. 3  is a bottom view of a ceiling fan of  FIG. 1 . 
         FIG. 4  is a bottom view of a ceiling fan of  FIG. 1 . 
         FIG. 5  is a bottom, perspective view of a portion of a ceiling fan embodying principles of the invention in another preferred form. 
         FIG. 6  is an exploded view of the portion of the ceiling fan of  FIG. 5 . 
         FIG. 7  is a bottom, perspective view of a portion of the ceiling fan of  FIG. 5 , shown with portions of the blade iron arms. 
         FIG. 8  is a perspective view of a link of a ring of the ceiling fan of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference next to the drawings, there is shown a ceiling fan  10  having a motor housing  11  which encases an electric motor  13  connected to a source of electric power by unshown wires. The motor  13  includes a bottom mounting plate  14  that rotates and thereby drives an annular array of blade irons  16 , each having a blade  17  mounted thereto in conventional fashion. The motor bottom mounting plate  14  has an annular array of threaded mounting holes  19  and a centrally positioned, raised, annular stop  20 . 
     Each blade iron  16  has a motor mounting flange  21  configured to be coupled with the bottom mounting plate  14  of the electric motor  13 . The mounting flange  21  has an elongated slot  23  therethrough which is aligned with the threaded mounting hole  19  of the bottom mounting plate  14 . A retaining member in the form of a mounting bolt or screw  24  extends through the elongated slot  23  and is threadably received in the mounting hole  19 . The mounting screw  24  however allows radial and pivotal movement of the blade iron  16  relative to the bottom mounting plate  14  of the motor. The motor mounting flange  21  also includes a keyhole shaped hole  25 . 
     The ceiling fan  10  also includes an annular balancing member in the form of a balancing ring  28  positioned concentrically about the annular stop  20 . The concentric positioning of the balancing ring allows for limited movement relative to the bottom mounting plate  14 . The central hole  29  within the balancing ring is defined by inner walls  30  which contacts the annular stop  20  to limit the radial movement of the balancing ring  28 . The balancing ring  28  includes an annular array of rivets  32  which are received withing the keyhole shaped hole  25  of the blade irons  16 . 
     In use, the balancing ring  28  initially is centrally positioned so that the blade irons are equally spaced from the center point of the bottom mounting plate  14 , as shown in  FIG. 3 . The operation of the motor  13  rotates the motor bottom mounting plate  14 , thereby rotating the blade irons  16  and blades  17 , creating a centrifugal force upon each blade iron. Should a heavier combined blade iron and blade  35  cause an imbalance due to it having a weight greater (resulting in a greater centrifugal force) than the other combinations of blade irons and blades  36 , the ceiling fan automatically balances itself in a manner described in more detail hereinafter. Of course, other factors previously recited may also cause an off-balancing of a combined blade iron and blade, for ease of description described hereinafter as simply the blade iron. 
     As shown in  FIG. 4 , the ceiling fan corrects this off-balancing by establishing an equilibrium balance through the subsequent relative movements of the blade irons. Here, the heavier blade iron  35  moves in an outboard direction from the center of the bottom mounting plate  14  because of its relative weight. The outboard movement of the heavier blade iron  35  is illustrated by arrow H. The outboard movement of the heavier blade iron  35  forces the balancing ring  28  coupled therewith to move outboard in relatively the same direction, as illustrated by arrow R. 
     The outboard movement of the balancing ring  28  in direction H causes the other blade irons  36  to pivot and/or longitudinally move in an “opposite” direction to the movement of the heavier blade iron  35 , as indicated by arrows L. The term opposite is intended to denote a direction generally away from the direction of the heavier blade iron  35  eventhough such movement is not 180 degrees in the opposite direction. For example, the movement of the two oppositely disposed blade irons  36  is indicated by arrows L, which is shown to be approximately 120 degrees from the direction of arrow H. The term opposite direction may mean a direction as little as 91 degrees offset from direction H. 
     The pivotal movement of the other blade irons  36  is caused by the pulling action on the blade irons  36  by rivets  32  as the balancing ring  28  moves in direction R and the blade irons are forced to pivot about mounting screws  24 . Similarly, the longitudinal movement of the other blade irons  36  is provided through the pulling action on the blade irons by rivets  32  thereby causing the blade irons to move relative to mounting screws  24  along the elongated slots  23 . As such, each mounting screw  24  and slot  23  establishes a first pivot about which the blade iron pivotally and radially moves relative to the motor, while the rivet  32  and keyhole shaped hole  25  establish a second pivot about which the blade iron pivotally moves relative to the balancing ring  28 . 
     The movement of the other blade irons  36  in a direction opposite to the direction of the heaviest blade iron counterbalance the outboard movement of the heavier blade iron  35 , thereby establishing an equilibrium balance upon the entire system. This equilibrium balance of the rotating blade irons/blades restricts the wobbling motion of the ceiling fan due to an off balanced blade iron and/or blade. 
     It should be understood that the rivets  32  may also be in the form of posts, screws, bolts, or other movement limiting means. 
     It should be understood that the stop  20  may be in the other forms such as seats, walls, flanges, posts, screws within oversized holes, or other obstructions. These stops may also be positioned within or outside of the balancing member, so long as they allow but limit radial movement of the balancing member. 
     It should be understood that the system will work equally for more than one blade iron and blade combination being off-balanced, as the entire system will move to an equilibrium position. 
     With reference next to  FIGS. 5 through 8  of the drawings, there is shown a ceiling fan  50  having an electric motor  53  connected to a source of electric power by unshown wires. The motor  53  includes a bottom mounting plate  54  that rotates and thereby drives an annular array of blade irons  56 , each having a blade mounted thereto in conventional fashion. Here, the blade iron  56  includes two separate pieces, a blade iron mounting bracket  57  and a conventionally styled blade iron arm  58 . The motor bottom mounting plate  54  has an annular array of threaded mounting holes  59 . 
     Each blade iron arm  58  has a motor mounting flange  61  configured to be coupled with the blade iron mounting bracket  57 . The mounting iron mounting bracket  57  has an elongated slot  63  therethrough which is aligned with the threaded mounting hole  59  of the bottom mounting plate  54 . A retaining member in the form of a mounting bolt or screw  64  extends through the elongated slot  63  and is threadably received in the mounting hole  59 . The mounting screw  64  however allows radial and pivotal movement of the blade iron mounting bracket  57 , and thereby the entire blade iron  56 , relative to the bottom mounting plate  54  of the motor. The blade iron arm  58  is coupled to the blade iron mounting bracket  57  through two mounting screws  65  passing through mounting holes  66  extending through the motor mounting flange  61 . Each blade iron mounting bracket  57  also has an inboard threaded mounting hole  67  therein opposite elongated slot  63 . 
     The ceiling fan  50  also includes an annular balancing member in the form of a segmented balancing ring  68 . The balancing ring  68  is comprised of a series of articulating, arcuate, stepped links  69 , best shown in  FIG. 8 , i.e. the ring  68  has multiple joints to allow articulated and flexible movement of the links  69  and thereby the entire ring. The number of stepped links  69  preferably equals the number of blade irons. Each link  69  has an upper portion  71  with a hole  72  therethrough and a lower portion  73  with a hole  74  therethrough. A ring mounting screw  75  passes through the upper portion hole  72 , through an adjacent link&#39;s lower portion hole  74  and into the threaded mounting hole  67  of the blade iron mounting bracket  57 . The concentric positioning of the balancing ring  68  allows for limited movement relative to the bottom mounting plate  54   
     In use, the balancing ring  68  initially is centrally positioned so that the blade irons are equally spaced from the center point of the bottom mounting plate  54 , similarly to that previously described in the first embodiment. The operation of the motor  53  rotates the motor bottom mounting plate  54 , thereby rotating the blade irons  56  and blades  57 , creating a centrifugal force upon each blade iron. Should a heavier combined blade iron and blade cause an imbalance due to it having a weight greater (resulting in a greater centrifugal force) than the other combinations of blade irons and blades, the ceiling fan automatically balances itself in a manner described in more detail hereinafter. Of course, other factors previously recited may also cause an off-balancing of a combined blade iron and blade, for ease of description described hereinafter as simply the blade iron. 
     The ceiling fan corrects this off-balancing by establishing an equilibrium balance through the subsequent relative movements of the blade irons. As previously described, a heavier blade iron moves in an outboard direction from the center of the bottom mounting plate  54  because of its relative weight. The outboard movement of the heavier blade iron, through the movement of the blade iron mounting bracket  57 , forces the balancing ring  68  coupled therewith to move outboard in relatively the same direction. The segmenting of the balancing ring also allows the ring to elongate in the direction of the heavier blade iron, thereby pulling the adjacent blade iron mounting brackets  57  on either side of the heavier blade iron greater than the remaining two blade iron mounting brackets distal the heavier blade. It is believed that this elongation of the ring provides a greater balancing effect on the blade irons and blade than compared to the solid ring of  FIGS. 1-4 . 
     The outboard movement of the balancing ring  68  causes the other blade irons to pivot and/or longitudinally move in an “opposite” direction to the movement of the heavier blade iron. The term opposite is intended to denote a direction generally away from the direction of the heavier blade iron eventhough such movement is not 180 degrees in the opposite direction. 
     The pivotal movement of the other blade irons is caused by the pulling action on the blade iron mounting brackets by mounting screws  75  as the balancing ring  68  moves and the blade iron mounting brackets  57  are forced to pivot about mounting screws  64 . Similarly, the longitudinal movement of the other blade irons is provided through the pulling action on the blade iron mounting brackets by mounting screws  75  thereby causing the blade iron mounting brackets to move relative to mounting screws  64  along the elongated slots  63 . As such, each mounting screw  64  and slot  63  establishes a first pivot about which the blade iron pivotally and radially moves relative to the motor, while the mounting screw  75  and mounting hole  67  establish a second pivot about which the blade iron pivotally moves relative to the balancing ring  68 . 
     The movement of the other blade irons in a direction opposite to the direction of the heaviest blade iron counterbalance the outboard movement of the heavier blade iron, thereby establishing an equilibrium balance upon the entire system. This equilibrium balance of the rotating blade irons/blades restricts the wobbling motion of the ceiling fan due to an off balanced blade iron and/or blade. 
     It should be understood that the system will work equally for more than one blade iron and blade combination being off-balanced, as the entire system will move to an equilibrium position. Also, the blade iron may be of unitary construction with the mounting brackets  57  formed with or fixedly mounted with the arms  58 . 
     It should be understood that the current invention is not intended to be limited to ceiling fans and may apply equally to all types of fans. 
     It thus is seen that a ceiling fan is now provided which balances itself. While this invention has been described in detail with particular references to the preferred embodiments thereof, it should be understood that many modifications, additions and deletions, in addition to those expressly recited, may be made thereto without departure from the spirit and scope of the invention as set forth in the following claims.