Abstract:
A wind turbine  20  has a turbine wheel  22  with a perimeter rim  24  and/or an intermediate rim  117  that are concentric with the axis of rotation of the turbine wheel. Electrical generators  46  and  48  are placed in engagement with the rims, with the generators formed in pairs that engage opposite surfaces of the rims. The electrical generators are mounted so that they may move laterally in response to the axial “wobble” likely to occur in the rims of the turbine wheel.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part of U.S. patent application Ser. No. 12/426,494, filed on Apr. 20, 2009, now U.S. Pat. No. 8,109,727 and of Ser. No. 12/432,837, filed Apr. 30, 2009, now U.S. Pat. No. 7,825,532 and of Ser. No. 12/481,817, filed on Jun. 10, 2009. 
    
    
     FIELD OF THE INVENTION 
     This invention concerns a wind turbine assembly for generating electricity in response to the movement of atmospheric wind. 
     BACKGROUND OF THE INVENTION 
     Windmills have been used for many generations for the purpose of pumping water from the ground and for generating electricity. A basic advantage of the windmill is that it uses the power of atmospheric wind to rotate a wheel having radially extending blades. This rotary movement may be converted into various useful purposes. For example, wind turbines in the form of propellers mounted on towers have been placed in areas where steady winds are prevalent and the wind turbines are used to generate electricity. An electrical generator usually is positioned near the axis of rotation of the propellers, adding the weight of the generator to the upper portion of the mast of the assembly The blades of the conventional large wind turbines are large and made of expensive rigid material and are constructed to have the blades extend radially from a central hub, with no extra support at the outer tips of the blades. The conventional wind turbine blades rotate at a high rate of revolutions and must withstand both the centrifugal forces generated by the fast revolution of the blades and the cantilever bending forces applied to the blades by the wind. Since the outer portions of the blades usually move at a very high velocity and are engaged by strong winds, the larger the blades the stronger they must be and the more expensive they become. Thus, there is a practical limit as to the length and width of the blades. 
     Another wind turbine type has rigid propellers that appear to be rigidly mounted to circular perimeter rims that support the outer ends of the propellers, as shown in U.S. Pat. Nos. 1,233,232 and 6,064,123. Rubber tires or other rotary objects are placed in positions to engage the outer rim so as to rotate the rubber tires, with the driven tires rotating the rotor of a generator. Thus, the rotation of the wind turbine is used to generate electricity. 
     The perimeter rim of a large wind turbine is likely to rotate in an irregular circular path so that at one position about the path of the rim the rim appears to wobble in an axial direction, parallel to the axis of rotation of the turbine wheel. This irregular rotation may be caused by several conditions, such as by wind turbulence, a change in wind velocity, equipment vibration, changes in wind direction, and imprecise formation and/or warping of the perimeter rim and its supporting structure. The larger the diameter of the wind turbine, the more likelihood of rotation of the rim in an irregular path and the more likelihood of greater amplitude of the axial displacement of the irregular movement of the perimeter rim. 
     One of the advantages of a turbine wheel with a perimeter rim is that the electrical generator(s) may be positioned at the rim at the lower arc of rotation of the rim where the generators are closer to the ground or other low supporting surface to remove the weight of the generator from the upper portion of the mast. Also, the position of the generator at a rim of the turbine wheel gives more access for installation, maintenance, repair and replacement of the generator. However, if the perimeter rim of the wind turbine wobbles during operation, it may be difficult to maintain the generator in proper alignment with the rim and it appears likely that stress between the generator and the turbine wheel will occur. Also, if multiple ones of the generators are placed in operative locations about an arc of the rim of the turbine, the potential problems caused by the wobbling rim appear likely to be more prevalent. 
     While is desirable to make a wind turbine that does not wobble during rotation, from a practical viewpoint it is likely that even the more perfect wind turbines will wobble to some extent when rotating. Accordingly, it would be desirable to have a connection between the rim of a wind turbine and one or more electrical generators that accommodates the rotation of the rim when the rim tends to wobble in an axial direction. 
     SUMMARY OF THE DISCLOSURE 
     Briefly described, this disclosure concerns a wind turbine assembly for generating electricity that includes a turbine wheel mounted on a support and rotatable about a laterally extending central axis, the turbine wheel including a circular rim concentric with and rotatable about the central axis, and an electrical generator in driven relationship with the circular rim. 
     The wind turbine may also include sail wings formed of fiberglass or other relatively flexible material, with shape control means carried by the turbine wheel for rotating at least one of the ends of the sail wings about the longitudinal axis of the sail wings to form a pitch or twist in the sail wings. 
     The wind turbine may also include a moveable support configured for supporting an electrical generator and for moving the electrical generator in response to the change in axial position of the circular rim of the turbine wheel at the position of the electrical generator. The moveable support may include a pair of wheels straddling the circular rim and in driving relationship with the electrical generator. 
     The wind turbine assembly may further include a guide wheel in engagement with the circular rim for moving the electrical generator in response to the change in axial position of the circular rim at the position of the electrical generator. 
     The wind turbine may include a biasing means for urging the guide wheel into contact with the circular rim. The biasing means may include air bellows, coil springs or other means by which the wobbling of the circular rim is accommodated. 
     A positioning wheel may be carried by a movable support, with the positioning wheel making contact with the circular rim for moving the movable support in response to the change of position of the circular rim at the movable support. In addition to the positioning wheel, at least one driving wheel carried by the movable support may be placed in contact with the circular rim and connected to the electrical generator for driving the electrical generator in response to the rotation of the wind turbine wheel. The positioning wheel keeps the driving wheel in contact with the rim of the turbine wheel. 
     Other features and advantages of the structure and process disclosed herein may be understood by reading the following specification in view with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevational view of a wind turbine, according to this description. 
         FIG. 2  is a side cross sectional view of the wind turbine of  FIG. 1 . 
         FIG. 3  is a detailed illustration of electrical generators and a portion of the perimeter of a turbine wheel, showing how the electrical generators may be driven by the circular perimeter rim of the wind turbine. 
         FIG. 4  is a detailed illustration, similar to  FIG. 3 , but showing the second arrangement of the electrical generators being driven by the perimeter circular rim of the turbine wheel. 
         FIG. 5  is a plan view of the driven wheels and their respective generators of  FIG. 4 , taken along lines  5 - 5  of  FIG. 4 . 
         FIG. 6  is a side cross sectional view, similar to  FIG. 4 , showing a portion of the perimeter rim of a turbine wheel and another arrangement of the electrical generators that may be driven by the perimeter rim. 
         FIG. 7  is a side elevational view of another wind turbine, with the wind turbine having a circular perimeter rim and an intermediate circular rim, both concentric with the axis of rotation of the turbine wheel. 
         FIG. 8  is a partial front view of the wind turbine of  FIG. 7 , showing a portion of the turbine wheel that includes the intermediate circular rim and the electrical generators and their movable support in engagement with the intermediate rim. 
         FIG. 9  is a closer front view to the electrical generators of  FIG. 8 . 
         FIG. 10  is a side elevational view of a portion of an intermediate rim of a wind turbine and the associated electrical generators of  FIG. 8 , showing an alternate arrangement of the driven wheels, guide wheel, and electrical generators as mounted to the perimeter rim of the turbine wheel. 
         FIG. 11  is a close front view of the electrical generators, similar to  FIG. 9 , but showing the electrical generators engaging an offset perimeter rim. 
         FIG. 12  is a side view of the turbine wheel of  FIG. 11 , showing the offset perimeter rim and the sailets extending radially from the perimeter framework. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the drawings in which like numerals indicate like parts throughout the several views,  FIG. 1  discloses a wind turbine  20  that includes a turbine wheel  22  and has a perimeter rim  24  and a perimeter framework  26  that supports the perimeter rim. The perimeter framework is a network of angle braces  26  which supports the outer circular perimeter rim  24 . The outer circular perimeter rim may be formed of arcuate segments. 
     The axle structure  28  at the center of the perimeter rim defines a central axis of rotation and a plurality of sail wing assemblies  30  extend between the axle structure  28  and the perimeter framework  26 , with the sail wings extending radially from the axle structure. A plurality of cables  32  extend from the axle structure radially outwardly to the perimeter framework  26  and hold the perimeter framework in place. 
     As shown in  FIG. 2 , the plurality of cables  32  converge inwardly as they extend from the axle structure  28  toward the perimeter framework  26 , providing both radial and axial support for the perimeter framework  26  and the perimeter rim  24 . The axle structure is mounted on an upright mast  34 , with the mast mounted on a ground support  36 . The mast may be rotated at the junction  38  between the mast  34  and ground support  36 , so as to face the turbine wheel into the oncoming wind. 
     Each of the sail wing assemblies  30  are rotatable about their longitudinal axis by pivotal mounting of the outer sail end supports  40  and inner sail end supports  42 . The sail end supports  40  and  42  are each mounted intermediate their ends to bearings that are supported by the perimeter framework  26  so that the sail end supports  40  and  42  rotate the sail wing assemblies about their respective longitudinal axes to adjust the pitch and twist of the sail wing assemblies so as to form the most desirable configuration of the sail wing assemblies for catching the atmospheric wind. 
       FIGS. 1 and 2  also show at least one electrical generator supported at the bottom arc of rotation of the perimeter rim  24  of the turbine wheel  22 . For example,  FIG. 2  shows a platform  44  that supports a pair of generators  46  and  48 . Likewise,  FIG. 1  shows a similar mounting of generators and platforms  44 ,  46  and  48  disposed in the lowermost arc of rotation of the turbine wheel  22  in a clock-wise direction as indicated by arrow  50 . 
       FIG. 3  shows a generator assembly  52  that includes the platform  44  and generators  46 A and  46 B. The generators are mounted on guide support rails  54 , with an arrangement of rollers  56  engaging the rails  54 . This allows the generators to be moved axially, in the direction of the axis of rotation of the turbine wheel, which is left and right as shown by the double headed arrow  66  in  FIG. 3 . 
     Each generator is connected to a reduction gear  58 A,  58 B, respectively, and drive shafts  60 A and  60 B extend from the reduction gears to a wheel member  62 A,  62 B, respectively. The wheel members may be conventional rubber tires mounted on rims, but other rotary type wheel members may be used, as desired. 
     Perimeter rim  24  has opposite facing parallel surfaces that are engaged by the wheel members  62 . In order to assure proper engagement of the wheel members  62  with the perimeter rim  24 , a turnbuckle  64  connects the reduction gear housings of the reduction gears  58  so that when the turnbuckle  64  is tightened, the wheel members compress against opposite surfaces of the perimeter rim  24 , causing the wheel members  62  to rotate in response to circumferential movement of the perimeter rim  24 . 
     With the arrangement of the generator assembly  52  of  FIG. 3 , it can be seen that should the perimeter rim  24  experience some axial movement or wobbling as indicated by arrows  66 , the generator assembly will be able to move in the same directions and at the same amplitude of the axial movement  66  while the wheel members  62 A and  62 B retain positive engagement with the perimeter rim  24 . Since the turnbuckle  64  tends to clamp the wheel members  62 A and  62 B into engagement with the perimeter rim  24 , continuous rotary movement will be imparted from the perimeter rim  24  to the wheel members  62 A and  62 B, and the rotary motions from the wheel members will be transmitted through the drive shafts  60 A and  60 B, reduction gears  58 A and  58 B to the generators  46 A and  46 B. 
       FIG. 4  shows another form of generator assembly  72  which includes generators  76 A and  76 B that are mounted by horizontal support arms  74 A and  74 B, respectively, and the support arms are pivotally mounted to the upright support shaft  75  that is supported, in turn, by the platform  44 . 
     The reduction gears  78 A and  78 B connect the generators  76 A and  76 B through the drive shafts  80 A and  80 B to the wheel members  82 A and  82 B that engage the perimeter rim  24 . The turnbuckle  84  is connected to the reduction gears  78 A and  78 B, drawing the generators  76 A and  76 B, reduction gears  78 A and  78 B, and the wheel members  82 A and  82 B together so that the wheel members  82 A and  82 B make positive engagement with the perimeter rim  24  of the turbine wheel  22 . 
     As shown in  FIG. 5 , which is a top view taken along lines  5 - 5  of  FIG. 4 , the horizontal support arms  74 A and  74 B are pivotally connected to the upright support shaft  75  so that they are movable about the upright support shaft  75  in arcs as indicated by the double-headed arrows  86 A and  86 B. This allows the wheel members  82 A and  82 B, the reduction gears  78 A and  78 B, and the generators  96 A and  96 B to oscillate in unison in the directions indicated by the arrows  86 A and  86 B, thereby compensating for axial movement of the perimeter rim  24 . 
       FIG. 6  shows yet another embodiment of the generator assembly  92 . The generators  96 A and  96 B, their respective reduction gears  98 A and  98 B and their drive shafts  100 A and  100 B are driven by the wheel members  102 A and  102 B that are in engagement with the perimeter rim  24  of the turbine wheel  22 . The turnbuckle  104  maintains the wheel members  102 A and  102 B in constant compressive contact with respect to the opposite facing surfaces of the perimeter rim  24 . Horizontal support arms  104 A and  104 B support the drive shafts  100 A and  100 B on the upright support shaft  105 , similar to that arrangement shown in  FIG. 5 . 
     The upright support shaft  105  of  FIG. 6  is mounted on guide support rails  108  that are mounted in turn to the platform  44 . The movable connection made by the rollers  106  against the guide support rails allows the generator assembly  92  to move axially, parallel to the axis of rotation of the turbine wheel, as indicated by double-headed arrow  109 . This allows the generator assembly  92  to move in response to the axial movement or “wobbling” of the perimeter rim  24  so that the wheel members  102 A and  102 B maintain constant engagement with the perimeter rim  24 . 
       FIG. 7  illustrates another embodiment of a wind turbine  110  that includes a turbine wheel  112  having a perimeter rim  114  and a perimeter framework  115  and an intermediate framework  116  and an intermediate rim  117 . As shown in  FIG. 8 , the intermediate framework  116  is structured in a manner similar to the structure of the perimeter framework  114  in that it includes a network of angled braces and is formed in a circle that is coaxial with both the perimeter rim  114  and the central axis of rotation  119 . A series of intermediate sail wings  120  are supported at their inner ends by the axle structure  118  and at their outer ends by the intermediate framework  116 . Likewise, outer sail wing assemblies  121  are supported at their ends by intermediate framework  116  and perimeter framework  115 . 
     As shown in  FIG. 7 , a series of axially extending spars  124  are supported by the intermediate framework  116 , and intermediate rim  117  is supported by the spars  124 . The intermediate rim  117  is positioned between the mast  128  and the cables  130  and  132  so that it is outside of the cables  130  and  132  that extend from the axle structure  118  out to the perimeter framework  115  and the intermediate framework  116 . 
     As shown in  FIGS. 9 and 10 , electrical generators  140 A and  140 B are supported adjacent the intermediate rim  117  in the lower arc of movement of the intermediate rim  117 . Support plate  142  is rigidly mounted to the mast  128 . The electrical generators  140 A and  140 B are mounted on movable support  144 . Movable support  144  is mounted to guide support rails  148  so that the movable support  144  moves with respect to mast  128  as indicated by the double-headed arrow  150 . The electrical generators  140 A and  140 B are operatively connected through the gear reducers  152 A and  152 B, and the gear reducers are connected in turn to the wheel members  154 A and  154 B, respectively. A turnbuckle (not shown in  FIG. 10  but similar to turnbuckle  64  of  FIG. 3 ) connects the gear reducers  152 A and  152 B together so that the wheel members are in positive engagement with the opposite surfaces of the intermediate rim  117  of the turbine wheel. 
     As shown in  FIG. 10 , guide wheel  156  is supported on the movable support  144  and engages the outward facing lateral surface of the intermediate rim  117 . 
     At the other end of the movable support  144  is a biasing means for urging the guide wheel  156  into constant contact with the outward face of the intermediate rim  117 . The biasing means may include bellows  158 A and  158 B that are backed at one end against a stationary plate  160  and which engage the adjacent edge of the movable support  144 . In the alternative, a coil spring or other biasing means may be used to continuously urge the guide wheel  156  into engagement with the intermediate rim  117 . This maintains the wheel members  154 A and  154 B in aligned contact with intermediate rim  117 . Thus, if there is any axial wobbling of the intermediate rim  117 , the guide wheel will follow the axial movement of the intermediate rim, moving the support  142 , generators  140 A and  140 B and associated structure axially as shown by barrow  150 , maintaining the wheel members  154  in constant contact with the intermediate rim  117 . This avoids interruption of the rotary movement applied by the intermediate rim  117  to the wheel members  154 A and  154 B. 
       FIGS. 11 and 12  show a turbine wheel  162 , mast  164 , and electrical generators  166 A and  166 B that are similar to those of  FIG. 9 . However, the perimeter rim  168  is offset from the perimeter framework  172 , as shown in  FIG. 12 . The plurality of spars  170  support the perimeter rim  168  from the perimeter framework  172 . The electrical generators are movably mounted with respect to the mast  164  as previously described so that the wheel members  174 A and  174 B engage opposite sides of the perimeter rim  168 , as previously described. The guide wheel  176  bears against the adjacent surface of the perimeter rim  168 , keeping the wheel members  174 A and  174 B in proper alignment with the perimeter rim  168 . 
     A plurality of short sail wings, identified as “sailets,”  180  are attached to the perimeter framework  172 , extending radially outwardly from the perimeter framework  172 . The sailets  180  are angled so as to form a pitch with respect to the oncoming atmospheric wind. The sailets typically will be rigid and relatively short in comparison to the sail wings of the turbine wheel so that they do not require additional support at their outer ends. The sailets provide additional surfaces for catching the wind and therefore increase the force of the rotary motion taken by the wind turbine from the oncoming wind. 
     It will be understood by those skilled in the art that while the foregoing description sets forth in detail preferred embodiments of the present invention, modifications, additions, and changes might be made thereto without departing from the spirit and scope of the invention, as set forth in the following claims.