Abstract:
Disclosed herein are embodiments of a hub comprising a hub shell provided with a first flange and a second flange, a composite axle that is provided with a plurality of stops, a first end, and a second end, a first end cap and a second end cap, wherein the first end cap is secured to the first end of the composite axle, and the second end cap is secured to the second end of the composite axle.

Description:
FIELD 
       [0001]    Embodiments disclosed herein relate to drives and hubs used in human powered vehicles. 
       BACKGROUND 
       [0002]    A sprocket driven by a metal chain used with a hub employing an over-running clutch are known. In such applications, the hub houses the over-running clutch and hence is fabricated from a metal, often aluminum. However, the over-running clutch and the metal materials associated therewith suffer from a number of drawbacks. For one thing, the over-running clutch creates drag and is a complicated assembly of pawls which are noisy (and hence unsuitable for sensitive military applications). Furthermore, the metal materials used in the chain and the hubs are relatively heavy, thereby requiring more energy to put wheels in motion. Additionally, metal materials are prone to weaken when exposed to the corrosive effects of water and salts, both of which are often encountered on roads and other areas where axles are used. 
         [0003]    Consequently, there exists a long felt, but unmet, need to make wheels and wheel components lighter. There also exists a long-felt, but unmet, need to make wheel components last longer by withstanding the corrosive effects of road conditions. The present invention addresses this need by using a belt fabricated from an elastomeric material (such as a polyurethane) and the hub from a plastic material. Elastomeric and plastic materials are lighter than the metal materials currently used. Furthermore, these materials withstand the corrosive effects found where axles are used better than metals do. 
         [0004]    Accordingly, the present invention is directed to overcoming these and other problems inherent in prior art drives, hubs, and wheels. 
       SUMMARY 
       [0005]    The scope of the present invention is defined solely by the appended claims, and is not affected to any degree by the statements within this summary. Disclosed herein are embodiments of an belt with asymmetrical teeth, a plurality of pulleys, and at least one treadle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is cross-sectional view of a belt constituting a presently preferred embodiment of the present invention; 
           [0007]      FIG. 2  is cross-sectional view of the belt shown in  FIG. 1 , with fibers depicted as circles representing reinforcing material; 
           [0008]      FIG. 3  is a cross-sectional view of the belt illustrated in  FIG. 1 ; 
           [0009]      FIG. 4  is a side view of a pulley representing a preferred embodiment of the present invention; 
           [0010]      FIG. 5  is a perspective view of a pulley representing a preferred embodiment of the present invention; 
           [0011]      FIG. 6  is cross-sectional view of the belt of  FIG. 1  and the pulley of  FIGS. 4 and 5 ; 
           [0012]      FIG. 7  is a cross-sectional view of the pulley of  FIGS. 4 and 5 ; 
           [0013]      FIG. 8  is a perspective view of a driven pulley representing a preferred embodiment of the present invention; 
           [0014]      FIG. 9  is a cross-sectional view of the pulley shown in  FIG. 8 ; 
           [0015]      FIG. 10  is a cross-sectional view of the pulley of  FIG. 8  and the belt of  FIG. 1 ; 
           [0016]      FIG. 11  is a cross-sectional view of the pulley of  FIG. 8 ; 
           [0017]      FIG. 12  is a side view of a vehicle representing a preferred embodiment of the present invention; 
           [0018]      FIG. 13  is a side view of the belt of  FIG. 1 ; 
           [0019]      FIG. 14  is a close-up side view of the belt of  FIG. 13 ; 
           [0020]      FIG. 15  is a perspective view of the pulley of  FIG. 8  with a spoke ring; 
           [0021]      FIG. 16  is a cross-sectional view of the compound fit between the spoke ring (designated “ 900 ”) and the driven pulley (designated “ 300 ”); 
           [0022]      FIG. 17  is a perspective view of the spoke ring shown in  FIGS. 15 and 16 ; 
           [0023]      FIG. 18  is a cross-sectional view of a portion of the spoke ring shown in  FIG. 17 ; 
           [0024]      FIG. 19  is a cross-sectional view of the driven pulley and driven hub; 
           [0025]      FIG. 20  is a cross-sectional view of a treadle constituting a presenting preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    A human-powered vehicle  100  is depicted in  FIG. 12 . As shown therein, the human-powered vehicle  100  (hereinafter referred to simply as the “vehicle  100 ”) is provided with a plurality of pulleys  200 ,  300 , referred to as a “first” pulley  200  and a “second” pulley  300  to distinguish one from the other. The vehicle  100  is also provided with a belt  400  that is positioned, at least in part, about the pulleys  200 ,  300  through use of a plurality of rollers (which are collectively designated “ 800 ”). The vehicle includes a retractor  500  that includes a retractor cord  510  and a power cord  520 . 
         [0027]    The power cord  520  is connected to the first pulley  200  and a treadle (shown in Figure. During a power stroke, the power cord  520  is placed in tension which is released by rotating the first pulley  200  and placing the retractor cord  510  in tension. During a recovery stroke, the tension on the retractor cord  510  is released by rotating the first pulley in an opposing direction, which rewinds the power cord  520  about the first pulley  200  for the next power stroke. 
         [0028]    As  FIG. 12  illustrates, the pulleys  200 ,  300 , the belt  400 , and the retractor  500  are located within a housing  600 . As  FIG. 12  also illustrates, the vehicle  100  is provided with a wheel  700 . In the presently preferred embodiment, the vehicle  100  is provided with a plurality of wheels  710 ,  720 ,  730  (a front wheel  710  and a rear wheel  720 ). Nonetheless, one of skill in the art will understand that a vehicle  100  with three wheels (such as a tri-cycle) and a vehicle with four wheels are within the scope of the present invention. 
         [0029]      FIG. 13  depicts the belt  400  in an unbent and unflexed state and is hence shown as generally circular with an axis  440  and a circumference  441 . The belt  400  is fabricated by being spin cast in a barrel. A reinforcing material, preferably a thread, is helically wound around a mandrel inside the barrel. Because the belt  400  is molded in a predetermined shape, preferably circular, material memory is imparted to the belt  400 . Hence, the belt  400  returns to its molded shape, which, in the preferred embodiment, is circular. 
         [0030]    As the foregoing indicates, by changing the thickness of the belt  400  or by changing the elastomer to a harder polyurethane, by way of example and not limitation, the material memory of the belt  400  is changed. Thus, the degree to which the belt  400  is biased to disengage a pulley is either increased or decreased. A thicker belt fabricated with a harder polyurethane as an elastomeric material has stronger material memory to return to its molded shape (preferably circular) and hence is provided with a stronger bias to disengagement. Conversely, a thinner belt with a softer polyurethane has weaker material memory for its circular molded shape and hence a weaker bias to disengagement. 
         [0031]    An elastomer is added to the barrel as the barrel is spun. In the presently preferred embodiment, the elastomer is a thermoset plastic; however, in alternative embodiments, a rubber is used. The barrel is spun about its axis to provide the belt  400  with a circular shape with a circumference. Because the belt  400  is fabricated through spin casting, the belt  400  is endless; however, in an alternative embodiment, the belt  400  is extruded in a length, cut, and spliced to form a circular shape. Because the reinforcing material is threaded about the axis of the barrel, the reinforcing material extends about the axis and is generally co-planar with respect to the circumference of the belt  400 ; in  FIG. 2 , the reinforcing material is shown as circular fibers extending from the page. Preferably, an aramid fiber is used as the reinforcing material; however, in alternative embodiments, a glass fiber, a carbon fiber, or a polyester fiber are used. Additionally, the foregoing reinforcing fibers may be used together in combination. After spin casting, the elastomer is cured, preferably through the application of heat. After the elastomer is cured, the belt  400  is removed from the mold. The cured elastomer and the reinforcing material provide the belt  400  with a material memory such that, after the belt  400  is deformed from its circular shape, the belt  400  springs back to its original circular shape. 
         [0032]    Referring now to  FIG. 1 , a cross-sectional view of the belt  400  is illustrated therein. The belt  400  is provided with a plurality of teeth (designated collectively as “ 410 ”) and is configured to move relative to the pulleys  200 ,  300  in two directions of relative rotation, a first direction  431  and a second direction  432  (the terms “first” and “second” are used to distinguish one direction from the other). Those of skill in the art will appreciate that the two directions  431 ,  432  of movement oppose one another. 
         [0033]    During a power stroke, the first pulley  200  moves the belt  400  in the first direction  431 . The reinforcing material of the belt  400  effectively “pushes” the teeth  410  into engagement with the second pulley  300 . During a recover stroke, the first pulley  200  moves the belt  400  in the second direction  432 , during which, the material memory of the belt  400  causes the belt  400  to spring back to its original circular shape and thereby wholly disengage the second pulley  300 . 
         [0034]    Though  FIG. 1  illustrates four teeth (which have each been individually designated “ 411 ,” “ 412 ,” “ 413 ,” “ 414 ”), it should be understood that the belt  400  is provided with a multitude of teeth  410  with each tooth substantially the same as the others. As  FIG. 2  shows, each of the teeth  410  is provided with a tooth profile that is asymmetrical. In cross-section, each of the teeth includes a plurality of sides  421 ,  422  (referred to herein as a “first tooth side  421 ” and a “second tooth side  422 .” The second tooth side  422  is oriented and shaped to transmit torque while the first tooth side  421  is oriented and shaped to slip. As is shown, the first tooth side  421  is longer than the second tooth side  422 . In the preferred embodiment, the first tooth side  421  and the second tooth side  422  form a belt tooth angle  423  that measures between and degrees. 
         [0035]    Turning now to  FIG. 6 , a number of cross-sectional views of the first pulley  200  are included therein. As shown, the first pulley  200  is provided with a first pulley axis  211  and a first pulley circumference  212 . The first pulley  200  is also provided with a groove  220  that extends about the axis  211  and along the circumference  212  of the pulley  200 . Included within the groove  220  are a plurality of surfaces. As shown in  FIG. 6 , the groove  220  is provided with a first tapered surface  221  and a second tapered surface  222 , a first grooved side  223  and a second grooved side  224 , and a base surface  225 . 
         [0036]    The base surface  225  is oriented to be parallel to the circumference  212  of the pulley  200 . The grooved sides  223 ,  224  extend from the base surface  225  parallel to one another and are oriented to be generally orthogonal relative to the base surface  225  (and hence the circumference  212  of the pulley  200  as well). The grooved sides  223 ,  224  and the base surface  225  of the groove  220  are dimensioned to accept a band  230  of elastomeric material. As  FIG. 6  illustrates, the band  230  fits within the groove  220 . 
         [0037]    The tapered surfaces  221 ,  222  extend from the grooved sides  223 ,  224  at an angle  226  (referred to as a “groove angle  226 ” in order to distinguish this angle from other angles recited herein). The groove angle  226  measures between (and including) 7.5 and 10 degrees, with the preferred angle  226  measuring between (and including) 9 and 10 degrees. The tapered surfaces  221 ,  222  cooperate with the belt  400 . When the belt  400  and the first pulley  200  are in contact, the tension of the belt  400  and the tapered surfaces  221 ,  222  cause the belt  400  to crown and thereby contact the band  230  of elastomeric material. Thus, the degree to which the belt  400  and the pulley  200  are engaged is controlled. By providing the tapered surfaces  221 ,  222  with an angle  226  that is steeper, the belt  400  crowns more thereby putting the teeth  410  into greater contact with the band  230  of elastomeric material. Conversely, by providing the tapered surfaces  221 ,  222  with an angle  226  that is shallower, the belt  400  crowns less, and hence, the teeth  410  of the belt  400  are less in contact with the band  230 . With less contact, the belt  400  tends to slip, rather than engage, the first pulley  200 . Because contact between the teeth  410  of the belt  400  and the band  230  of elastomeric material is controlled, the degree of engagement between the belt  400  and the first pulley  200  is also controlled. Consequently, the first pulley  200  is configured to achieve a controlled slip. 
         [0038]    Band  230  is made of a harder material, the teeth  410  of the belt  400  are less able to bite into the band  230 , and hence, less normal pressure is exerted on the tapered surfaces  221 ,  222 . Thus, slip of the belt  400  on the surfaces  221 ,  222  is controlled and optimized for the anticipated maximum torque applied to the pulley  200   
         [0039]    By controlling slip of the belt  400 , different sets of teeth  410  engage the pulleys  200 ,  300 . Wear of the belt  400  is distributed. So too, wear of the pulleys  200 ,  300  is also distributed. 
         [0040]    Referring now to  FIG. 5 , the pulley  300  is shown. In the preferred embodiment, the pulley  300  is fabricated from powdered metal; however, in alternative embodiments, the pulley  300  is fabricated from a phenolic. In yet another alternative embodiment, the pulley  300  is fabricated from an epoxy resin that includes fiber reinforcement. 
         [0041]    The pulley  300  is generally cylindrical in shape and hence includes an axis  301  and circumference  302 . A plurality of pulley teeth  310  radiate from the circumference  302  of the pulley  300 . The pulley teeth  310  are shaped to cooperate with the teeth  410  of the belt  400 . As  FIG. 5  illustrates, each of the pulley teeth  310  is provided with a first tooth side  311  and a second tooth side  312  (referred to as a “first pulley tooth side” and a “second pulley tooth side” in order to distinguish sides of the pulley teeth  310  from the sides  421 ,  422  of the teeth  410  on belt  400 .) The sides  311 ,  312  of the pulley teeth  310  form an angle  313  (which shall hereinafter be referred to as a “pulley angle  313 ” in order to distinguish the angle  313  of the pulley teeth  310  from the angle  423  of the belt teeth  410 ). 
         [0042]    The pulley angle  313  according to the diameter of the pulley, with the pulley angle  313  of the preferred embodiment measuring 90. One of the sides  311 ,  312  of the pulley teeth  310  is oriented and shaped to engage the teeth  410  of the belt  400  (and thereby transmit torque to the rear wheel  720 ) while another side of the pulley teeth  310  is oriented and shaped so that the teeth  410  of the belt  400  slip over the pulley  300  (and thereby transmit no torque to the rear wheel  720 ). As  FIG. 5  illustrates, the first pulley tooth side  311  is longer than the second pulley tooth side  312 . 
         [0043]    As shown in  FIG. 2 , each of the pulley teeth  310  is provided with a first side  311  and a second side  312 . The second side  312  is oriented and shaped to transmit torque while the first pulley tooth side  311  is oriented and shaped to slip. Thus, when the teeth  410  of the belt  400  are moved over the teeth  310  of the pulley  300 , the belt  400  slips in one direction but engages and transmits torque in the other direction. 
         [0044]    During a power stroke, the first pulley  200  moves the belt  400  in the first direction  431  and the reinforcing material of the belt  400  “pushes” the teeth  410  of the belt  400  into contact with the teeth  310  of the second pulley  300 . Though the teeth  410  of the belt  400  are moved in the first direction  431 , the teeth  310  of the second pulley  300  may be rotating faster than the teeth  410  of the belt  400  (e.g. while traveling down a steep incline). In such a case, a first tooth side  421  on the belt  400  contacts a first tooth side  311  on the second pulley  300  (rather than the second tooth side  422  on the belt  400  contacting the second tooth side  312  on the pulley). Because the first tooth side  311  of the second pulley  300  and the first tooth side  421  of the belt  400  are both oriented and shaped to slip, the teeth of belt  400  slip over the second pulley  300 . 
         [0045]    A controlled slip is also created between the belt  400  and the first pulley  200 . The band  230  within the first pulley  200  is fabricated to control the engagement between the belt  400  and the first pulley  200 . Like the belt  400 , the band  230  is fabricated through spin casting. By adding softer elastomeric material during the spin casting the band  230  is rendered less prone to slipping. Because the band  230  is made of a softer elastomeric material, the teeth  410  of the belt  400  are more able to bite into the band  230 , and hence, greater control is achieved between the belt  400  and the band  230  (and by extension, the pulley  200  itself). Conversely, by adding harder elastomeric material during the spin casting of the band  230 , the band  230  is rendered more prone to slipping. Thus, the band  230  of the presently preferred embodiment creates a controlled slip of the belt  400  relative to the pulleys  200 ,  300 . 
         [0046]    Referring now to  FIG. 19 , a hub  350  is shown. As illustrated, the hub  350  is provided with an axle  360 , a bearing assembly  370 , and a spoke ring  380 . In the preferred embodiment, the axle  360  is a shaft that includes an aluminum and provided with a plurality of threads  363 . As  FIG. 19  shows, the axle  360  is generally cylindrical in shape and provided with a first end  361  and a second end  362 . Each of the ends  361 ,  362  of the preferred embodiment is threaded (though, in an alternative embodiment, a threaded bolt is used). A nut  364  is used to secure the hub  350  (and hence the wheel  200 ) to the frame  601  of the vehicle  100 . 
         [0047]    As noted above, the hub  350  is also provided with a bearing assembly  370 . Included therein is a bearing  371 , also referred to as an “inboard bearing,” and a bearing block  372 . As  FIG. 19  illustrates, the inboard bearing  371  includes a plurality of curved members  373 , which in the preferred embodiment are stainless steel balls In an alternative embodiment, the curved members are generally cylindrical in shape. As  FIG. 19  also illustrates, the bearing block  372  is a machined plastic with an inner diameter  374  that is dimensioned according to the outer diameter of the inboard bearing  371 . 
         [0048]    The bearing block  372  is also provided with a shoulder  375  and a flange  376 . As  FIG. 19  illustrates, the flange  376  is provided with a flange block diameter  377  which is dimensioned to be larger than the outer diameter  325  of the drive pulley  300 . The shoulder  375 , in turn, is provided with a shoulder diameter  378 . The shoulder diameter  378  is dimensioned according to the inner diameter  326  of the drive pulley  300 . Thus, the shoulder  375  of the bearing block  372  supports an end of the drive pulley  300 . Furthermore, because the flange  376  extends beyond the outer diameter  327  of the drive pulley  300 , the flange  326  acts as a guide for the belt  400 . 
         [0049]    The hub  350  is also provided with a spacer  340 . In the preferred embodiment, the spacer  340  is fabricated from a plastic that includes a wall  341 . The wall  341  of the spacer  340  is provided with a wall thickness of 1/16 of an inch. However, in an alternative embodiment, the spacer  340  (and hence the wall  341  of the spacer  340 ) is fabricated from a metal, such as a steel, and, in such an embodiment, is provided with a wall  341  with a thickness measuring 1/32 of an inch. Therefore, as the foregoing illustrates, the wall  341  of the spacer  340  is provided with a thickness that ranges between 1/32 to 1/16 of an inch. 
         [0050]    The spacer  340  abuts the spoke ring  380 . As  FIG. 19  illustrates, the spoke ring  380  is provided with a spoke flange  381 , which includes a plurality of holes for a plurality of spokes  382 . The spoke ring  380  rides on the pulley  300  via a compound fit. This compound fit is achieved at least in part through the frictional engagement of a surface on the spoke ring  380  and a surface on the pulley  300 . More specifically, the teeth  410  are provided with a step  314 . As illustrated in  FIG. 16 , the step  314  includes a generally cylindrical surface  316  and a radial surface  315  (which extends from the pulley  300  in a direction that is generally radial). 
         [0051]    As noted above and illustrated in  FIG. 12 , the vehicle  100  is provided with a plurality of rollers  800  that are positioned radially (at least in part) about the hub  350 . Though the rollers  800  are arranged about the hub  350 , the rollers  800  remain stationary relative to the hub  350  and are attached to a roller fixture  395 . As a result, the hub  350  is provided with a bearing  390  that rides on the outer surface of the pulley  300  (hereinafter the bearing  390  shall be referred to as the “outboard bearing” to distinguish it from the “inboard bearing  371 ”). Much like the inboard bearing  371 , the