Abstract:
The Gear Reduction Tricycle Wheel invention provides two methods of operation of a tricycle with the use of a simple locking pin. When the pin is inserted into the wheel, it operates as a standard wheel would. Without the pin in place, the wheel requires about four times less effort to move with a similar reduction in speed. This gives the option to move with superior control up, down, and over difficult terrain and within limited space (indoor, home, daycare). One can get the sensation of a good ride without the required distance. This new design in the wheel includes gears within the wheel where spokes usually are. In the absence of spokes, side disc plates support the tire rim and the gear axles.

Description:
RELATED APPLICATIONS 
       [0001]    There are no current pending applications. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to a three-wheeled vehicle where a front wheel assembly has a selectable gear reduction assembly. 
       BACKGROUND FOR THE INVENTION 
       [0003]    Many of us remember the tricycle as the first self-powered vehicle we ever rode. Its wide base makes for a very stable platform that is almost impossible to tip over. However, the direct drive wheel/pedal system makes it difficult for many children to pedal. It is especially a problem when on rough grade, or when trying to pedal uphill. Additionally, the large central tire has a tendency to slip on wet or smooth surfaces. Many children often require a push from a parent or care provider just to get going, which must be repeated each time the child stops moving. Some of these same issues are also apparent when using a wheelchair; another direct drive device. Accordingly, there exists a need for a means by which a direct driven wheel, such as on a tricycle, can be pedaled in an easier manner. The use of the present invention provides tricycle riders the ability to pedal their tricycles with reduced physical effort in a manner which is quick, easy, and effective. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0004]    The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which: 
           [0005]      FIG. 1  is an isometric view of a gear reduction drive wheel  10  in accordance with the preferred embodiment of the present invention; 
           [0006]      FIG. 2  is a section view along line A-A as shown on  FIG. 1  of the gear reduction drive wheel  10  in accordance with the preferred embodiment of the present invention; 
           [0007]      FIG. 3  is a schematic view of the gear reduction drive wheel  10  in a direct drive configuration in accordance with the preferred embodiment of the present invention; and, 
           [0008]      FIG. 4  is a schematic view of the gear reduction drive wheel  10  engaged in a gear reduction mode in accordance with the preferred embodiment of the present invention. 
       
    
    
     DESCRIPTION KEY 
       [0009]      
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                 10 
                 gear reduction drive wheel 
               
               
                 20 
                 hub 
               
               
                 25 
                 sun gear 
               
               
                 30 
                 sun gear tooth 
               
               
                 35 
                 gear lock aperture 
               
               
                 40 
                 lock pin 
               
               
                 45 
                 first crank 
               
               
                 50 
                 second crank 
               
               
                 55 
                 carrier bearing journal 
               
               
                 60 
                 frame bearing journal 
               
               
                 65 
                 first pedal 
               
               
                 70 
                 second pedal 
               
               
                 90 
                 fork 
               
               
                 95 
                 cap 
               
               
                 100 
                 threaded fastener 
               
               
                 105 
                 frame bearing 
               
               
                 110 
                 carrier plate 
               
               
                 115 
                 first lock aperture 
               
               
                 120 
                 carrier plate inner bearing 
               
               
                 125 
                 carrier plate outer bearing 
               
               
                 130 
                 idler plate 
               
               
                 135 
                 second lock aperture 
               
               
                 140 
                 idler plate inner bearing 
               
               
                 145 
                 idler plate outer bearing 
               
               
                 150 
                 gear cavity 
               
               
                 155 
                 reverse planet gear 
               
               
                 160 
                 reverse gear tooth 
               
               
                 165 
                 reverse gear bearing 
               
               
                 170 
                 reverse gear shaft 
               
               
                 175 
                 flange 
               
               
                 180 
                 flange fastener 
               
               
                 185 
                 outer planet gear 
               
               
                 190 
                 outer planet gear tooth 
               
               
                 195 
                 outer planet gear bearing 
               
               
                 200 
                 outer planet gear shaft 
               
               
                 205 
                 ring gear 
               
               
                 210 
                 ring gear tooth 
               
               
                 215 
                 rim 
               
               
                 220 
                 tire 
               
               
                 240 
                 tricycle 
               
               
                 245 
                 tricycle frame 
               
               
                 250 
                 drive wheel 
               
               
                   
               
             
          
         
       
     
       DESCRIPTION OF THE INVENTION 
       [0010]    The best mode for carrying out the invention is preserved in terms of its preferred embodiment, herein depicted within  FIGS. 1 through 4 . However, the invention is not limited to the described embodiments and a person skilled in the art will appreciate that many other embodiments of the invention are possible without deviating from the basic concept of the invention and that any such work around will also fall under scope of this invention. It is envisioned that other styles and configurations of the present invention can be easily incorporated into the teachings of the present invention, and only one particular configuration shall be shown and described for purposes of clarity and disclosure and not by way of limitation of scope. 
         [0011]    The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. 
       DETAILED DESCRIPTION OF THE FIGURES 
       [0012]    The present invention describes a gear reduction drive wheel (herein referred to as the “system”)  10 , which provides a means to include a gear reduction in the drive wheel  250  of a mode of transportation so as to be able to selectively increase the torque output capability of that mode of transportation. While this invention was originally conceived to function relative to a tricycle  240 , it is understood that such a system  10 , with the stated capabilities, can find broader applications without limiting the scope of this invention. 
         [0013]    Referring now to  FIG. 1 , an isometric view, and  FIG. 2 , a section view along line A-A as shown in  FIG. 1 , of the system  10 , according to the preferred embodiment of the present invention, are disclosed. The system  10  includes a sun gear  25  attached to a hub  20 , two (2) planet gears  155 ,  185  rotationally supported on gear shafts  170 ,  200 , and a ring gear  205  to which a rim  215  for a tire  220  is attached. The sun gear  25  is preferably configured to be a spur gear having an involute profile on a plurality of sun gear teeth  30 . The sun gear  25  may be attached to the cylindrical hub  20  in a variety of ways such as, but not limited to, splines, any of a variety of keys, or by other use of specific geometry. The hub  20  is provided with carrier bearing journals  55  and frame bearing journals  60  on each end. The carrier bearing journals  55  are portions of the hub  20  in proximity to either side of the sun gear  25  preferably having a consistent diameter. The carrier bearing journals  55  provide a landing onto which the inner races of an idler plate inner bearing  140 , on a first side, and a carrier plate inner bearing  120 , on a second side, are seated and secured by means of a press fit. The idler plate inner bearing  140  and the carrier plate inner bearing  120  are preferably commercially available ball bearings having some type of seal to exclude contaminants. It is understood that other types of bearings, such as needle or roller bearings, may be utilized without limiting the scope of the system  10 . Additional provisions, such as snap rings, fitted into snap ring grooves, may be included for the retention of the inner bearings  120 ,  145  without limiting the scope of the system  10 . The frame bearing journals  60  are configured to be outboard of the carrier bearing journals  55 . The frame bearing journals  60  are preferably slightly smaller in diameter than the carrier bearing journals  55  so as to minimize the distance through which the inner bearings  120 ,  145  must be pressed onto the hub  20 . Additional provisions, such as a hearing nut with a locking ring may be included for the retention of the frame bearings  110  on the hub  20 . 
         [0014]    Attached to, or formed with, the hub  20  are a first crank  45  located on a first end, and a second crank  50  located on a second end. The first crank  45  and the second crank  50  are configured to be oppositely oriented, radially projecting moment arms for the application of coupling about the axis of the hub  20  in order to introduce a rotary motion into the system  10 . A first pedal  65  is attached at a distal end of the first crank  45 , while a second pedal  70  is attached at a distal end of the second crank  50  so as to enable a user to exert the moment applied to the hub  20  utilizing their feet. 
         [0015]    The hub  20  is attached to a fork  90  which is in turn incorporated into the tricycle frame  245 . The fork  90  is configured to be a piece having any appropriate cross-sectional shape with two (2) vertical support tubes joined at an upper horizontal member. The fork  90  is provided with bearing seats capable of accommodating the outer races of the frame bearing  105  and partially encircling that frame bearing  105 . Each vertical support of the fork  90  is provided with a cap  95  at a lower end configured to be attached to the fork  90  by means of at least one (1) threaded fastener  100  and capable of retaining the frame bearing  105  within a bearing seat. 
         [0016]    An idler plate  130  is mourned on the idler plate inner bearing  140 . The idler plate  130  is preferably a circular metal plate which forms an outer cover for a gear cavity  150  on a first side and combines with the carrier plate  110  to support the tricycle frame  245  on the rim  215  and tire  220 . An idler plate outer bearing  145  is mounted on an outer diameter of the idler plate  130  and supports the rim  215  on a first side. A carrier plate  110  is mounted on the carrier plate inner bearing  120 . The carrier plate  110  is preferably a circular metal plate having provisions to accommodate the serviceable attachment of a reverse planet gear  155  and an outer planet gear  185  as well as forming an outer cover for the gear cavity  150  on a second side. A carrier plate outer bearing  125  is mounted on an outer diameter of the carrier plate  110  and supports the rim  215  on a second side. The idler plate outer bearing  145  and the carrier plate outer bearing  125  are preferably commercially available ball bearings having some type of seal to exclude contaminants. 
         [0017]    The reverse planet gear  155  is preferably a spur gear having an involute profile on a plurality of reverse planet gear teeth  160 . The reverse planet gear teeth  160  are meshed with the sun gear teeth  30  so that as the sun gear  25  rotates, the reverse planet gear  155  rotates in an opposite direction. In a preferred embodiment, the number of reverse gear teeth  160  on the reverse planet gear  155  is equal to the number of sun gear teeth  30  on the sun gear  25  and therefore the rotational speed of both gears  25 ,  155  is equal. It can be seen that the drive ratio of sun gear  25  to reverse planet gear  155  is equal to the ratio of the sun gear teeth  30  to the reverse gear teeth  160  and that in alternate embodiments this may be advantageously exploited. The reverse planet year  155  is mounted on a preferably cylindrical reverse gear shaft  170 . The reverse gear shaft  170  is provided with a preferably circular flange at a first end which is connected to the carrier plate  110  by means of a plurality of threaded flange fasteners  180  secured into complimentary threaded apertures (not shown) in the carrier plate  110 . A reverse gear bearing  165  is fitted into a central aperture (reverse gear bore) of the reverse planet gear  155  and allows a free rotation of the reverse planet gear  155  relative to the reverse gear shaft  170 . The reverse gear bearing  165  may be any type of bearing, such as needle, roller, or sleeve, appropriate to serve the intended function without limiting the scope of the system  10 . Additional provisions, such as a snap ring, fitted into a snap ring groove, may be included for the retention of the reverse planet gear  155  and the reverse rear bearing  165  on the reverse gear shaft  170 . 
         [0018]    An outer planet gear  185  is mounted onto an outer planet gear shaft  200  in a similar manner to the reverse planet gear  155 . The outer planet gear teeth  190  are meshed with the reverse gear teeth  160  such that as the reverse planet gear  155  rotates, the outer planet gear  185  rotates in an opposite direction. This counter revolution between the sun gear  25 , the reverse planet gear  155 , and the outer planet gear  185  results in the rotation of the outer planet gear  185  in the same direction as the sun gear  25 . An outer planet gear bearing  195  is fitted into a central aperture (outer planet gear bore) of the outer planet gear  185  to permit the free rotation of the outer planet gear  185  relative to the outer planet gear shaft  200 . In an alternate embodiment, the outer planet gear  185  may be fixed to the outer planet gear shaft  200  with provisions for allowing the outer planet gear shaft  200  to freely rotate relative to the carrier plate  110 . 
         [0019]    The ring gear  205  is preferably an internal gear having an involute profile on a plurality of ring gear teeth  210 . The ring gear  205  is affixed to the rim  215  and encircles the other gears  25 ,  155 ,  185  with the outer planet gear teeth  190  meshing with the ring gear teeth  210 . Since the ring gear  205  is an internal gear, i.e. the involute ring gear teeth  210  facing radially inward, the direction of revolution corresponds to the outer planet gear  185  and the sun gear  25 . Because the diameter of the ring gear  205  is much larger in comparison to the outer diameter of the outer planet gear  185  the rotational speed of the ring gear  205  will be proportionally reduced by the ratio of the number of outer planet gear teeth  190  to the number of ring gear teeth  210  (ω=n t185 /n t210 ). This will result in a multiplication of the transmitted torque to the ring gear  210  approximately equal to the inverse of the tooth ratio (τ=n t210 /n t185 ). The tire  220  is mounted onto the rim  215  and rotates in concert with the rim  215 . The tire  220  is configured to he a torus of a rubber material, or other similar polymer material. 
         [0020]    Referring now to  FIG. 3  a schematic view of the system  10  in a direct drive configuration, and  FIG. 4 , a schematic view of the system  10  engaged in a gear reduction mode, according to the preferred embodiment of the present indention, are disclosed. Disposed in the carrier plate  110  is a first lock aperture  115  configured to be a circular aperture for the sliding insertion of a cylindrical lock pin  40 . The sun gear  25  is provided with a similar gear lock aperture  35 . Disposed in the idler plate  130  is a corresponding second lock aperture  135 . When the gear lock aperture  35  in the sun gear  25  is in alignment with the first lock aperture  115  and the second lock aperture  135 , the lock pin  40  may be slidingly inserted, as depicted in  FIG. 3 , to result in the system  10  rotating as a single unit without any relative internal motion between any of the components in accord with any force applied to the first crank  45  via the first pedal  65  or to the second crank  50  via the second pedal  70 . When the lock pin  40  is not inserted through the apertures  35 ,  115 ,  135 , as illustrated in  FIG. 4 , the sun gear  25  is permitted to rotate relative to the reverse planet gear  155 , thus driving the outer planet gear  185  and the ring gear  205  in turn. 
         [0021]    It is envisioned that in an alternate embodiment the system  10  may be adapted to be utilized on the drive wheels of a wheelchair in order to permit a similar gear ratio change to facilitate mobility under certain conditions. 
       Operation of the Preferred Embodiment  
       [0022]    In accordance with the invention, the illustrated embodiment can be utilized by an enabled individual in a simple and straightforward manner with little or no training. After initial purchase or acquisition of the system  10 , it would be installed as indicated in  FIG. 1 . The method of installing and utilizing the system  10  may be achieved by performing the following steps: acquiring a model of the system  10  having a desired style to suit the taste of a user; positioning oneself upon a seat in the normal fashion; pedaling the tricycle  240  by means of the first pedal  65  and the second pedal  70  and utilizing the handlebars to steer the tricycle  240  in the desired path of travel. When the effort to pedal the tricycle  240  has increased due to an uphill grade or an increased rolling resistance of the tire  220  the user may remove the lock pin  40  from the drive wheel  250  to experience a decreased rotational speed of the drive wheel  250  with a corresponding decrease in the effort to pedal the tricycle  240 . 
         [0023]    The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.