Abstract:
A wheel with high strength flexible spokes of the present invention, including a rim and hub, and spokes between the rim and hub made of fibrous material that causes the spokes to be both lighter in weight and stronger than comparable steel spokes. The spokes are also flexible and resilient such that they can bend while retaining their integrity and strength. The wheel includes a nipple within the rim that receives the high strength spoke and allows for flexibility in adapting the spoke to wheels having differing shapes and sizes.

Description:
RELATED APPLICATION 
     This application claims the benefit of priority and is a continuation-in-part application to co-pending U.S. Utility application Ser. No. 13/487,253 filed 06/04/2012 entitled “Wheel With Flexible Wide-Body Spokes”. 
    
    
     FIELD OF INVENTION 
     The present invention is directed to vehicular wheels having high-strength and light-weight spokes, particularly bicycle, motorcycle, and wheelchair wheels. 
     BACKGROUND OF INVENTION 
     The most common construction for bicycle wheels includes spokes made of stainless steel or other metal. While stainless steel is strong, it is also heavy. Therefore, the spokes must be made as thin as possible to make them as light as possible. However, the thinner the spoke, the less strength it has. The thicker the spoke, the stronger it is. Therefore, in making spokes of steel, there is a tradeoff between making the spokes strong and making them lightweight. Thus, there is a need for a wheel with spokes that can be both lightweight and strong without having to deal with this tradeoff between the two. Another problem with steel spokes is that, if they are bent, they weaken and ultimately fail such that they must be replaced if bent. 
     One solution to this problem was presented in U.S. Pat. No. 5,110,190 which issued to Harold Johnson on May 5, 1992, for an invention entitled “High Modulus Multifilament Spokes And Method” (hereinafter the “&#39;190 patent”). The &#39;190 patent is fully incorporated herein by this reference. The &#39;190 patent discloses a high modulus multifilament non-rigid and rigid wheel spoke that includes a fiber mid-portion between a first and second end having attachment members affixed thereto. The &#39;190 patent also discloses methods of supporting a hub within a wheel rim by means of a plurality of spokes or by means of continuous lengths of spokes. 
     While the device presented in the &#39;190 patent clearly made advancements over the state of the art at that time, the device nevertheless has its shortcomings. For instance, the small diameter of the filament spokes requires that the spokes be maintained in a substantially axial arrangement with its connectors. This, unfortunately, makes the manufacturing of wheels incorporating the &#39;190 technology more difficult due to the of off-axis tension. Specifically, even though the spokes of the &#39;190 patent are orders of magnitude stronger than their metallic counterparts, the strength of the &#39;190 spokes is slightly decreased from its maximum strength due to the bend in the spokes as they leave the wheel rim when installed in a wheel. 
     U.S. Pat. No. 6,036,281 which issued on Mar. 14, 2000, to Richard Campbell and entitled “Low Rotational Mass Bicycle Wheel System” (hereinafter the &#39;281 patent), disclosed a bicycle wheel system having spokes extending radially from hub to spoke. The spokes are provided with fittings at its rim end which are constructed with minimal mass and fittings at the hub end which allow adjustment of the tension of the spoke. The spokes are constructed of a bundle of liquid crystal fibers having no significant creep surrounded by an extruded plastic jacket. 
     While the spoke presented in the &#39;281 patent certainly represents a milestone in bicycle wheel technology and light-weight wheel manufacturing, it nevertheless has its challenges with implementation. First of all, there are manufacturing challenges in keeping the spokes aligned with their connectors. In narrow-width wheel applications, the device disclosed in the &#39;281 are difficult to install as the alignment is important. This alignment results in increased assembly costs and overall product costs. 
     The present invention resolves these problems by providing spokes that are both lighter in weight than steel and significantly stronger than steel, and that are flexible such that they can bend without suffering damage. Moreover, due to their significant strength and durability, fewer numbers of spokes are required on wheels while still providing a lightweight wheel with superior strength. 
     SUMMARY OF THE INVENTION 
     The wheel with flexible wide-body spokes of the present invention provides the aforementioned advantages by providing a wheel including a rim and hub, and spokes between the rim and hub made of fibrous material that causes the spokes to be both lighter in weight and stronger than comparable steel spokes. The spokes are also flexible and resilient such that they can bend while retaining their integrity and strength. 
     Alternative embodiments of the wheel with high strength flexible spokes of the present invention include nipples for use within the wheel rims that provide flexibility in the angle which the spoke extends from the rim towards the wheel hub. A shortened nipple which sits fully within the rim such that the collar rests firmly against the inside of the rim and is accessible through the access hole formed in the rim is secured using a blade key received within a keyway for installation. An alternative includes a nipple formed to have a shoulder that is rounded and can pivot slightly within the rim to accommodate a slight departure angle for the spoke, and is held in place using a key corresponding to a keyway. A rounded nipple is sized to be received fully within the rim of a wheel and is formed with a rounded surface to mate closely with the internal surface of a wheel rim such that the rounded nipple can be secured in place with the spoke extending from the wheel at an angle, while maintaining the straightness of the spoke. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The aforementioned and other advantages of the wheel with flexible spokes of the present invention will become more apparent to those skilled in the art upon making a thorough review and study of the following detailed description of the invention when reviewed in conjunction with the drawings in which like references numerals refer to like parts, and wherein: 
         FIG. 1  is a side view of a first preferred embodiment of the wheel with flexible spokes of the present invention, showing the rim, hub, spokes between rim and hub, tubes attaching each spoke to the rim, and anchors attaching each spoke to the hub; 
         FIG. 2  is a rear detail view of the first preferred embodiment of the wheel with flexible spokes of the present invention, showing the hub, the angle between spokes on the left side of the wheel and spokes on the right side of the wheel, and the angle of the hub surface at the point of attachment of each spoke to the hub; 
         FIG. 3  is a cross-sectional view of the first preferred embodiment of the wheel with flexible spokes of the present invention, taken across line  3 - 3  of  FIG. 1 , showing cross-sectional portions of the rim and hub, and showing how each tube attaches each spoke to the rim via a nipple in the rim, and how each anchor attaches each spoke to the hub; 
         FIG. 4  is a cross-sectional view of the first preferred embodiment of the wheel with flexible spokes of the present invention, taken across line  4 - 4  of  FIG. 1 , showing a cross-sectional view of the fibers and jacket of one of the spokes; 
         FIG. 5  is a cross-sectional view of the first preferred embodiment of the wheel with flexible spokes of the present invention showing cross-sectional portions of the rim and hub, and showing how each tube, once attached to the rim, would extend away at an angle from the nipple in the rim; 
         FIG. 6  is a cross-sectional view of an alternative embodiment of the wheel with high strength flexible spokes of the present invention showing cross-sectional portions of the rim and hub, and showing a shortened nipple sized to be fully received within the rim and formed with a keyway to receive a key when secured during assembly of the wheel, and with the spoke extending away at an angle from the nipple in the rim; 
         FIG. 7  is a cross-sectional view of an alternative embodiment of the wheel with high strength flexible spokes of the present invention showing portions of the rim and hub, and showing a shouldered nipple sized to be fully received within the rim and formed with a keyway to receive a key when secured during assembly of the wheel, and with the shouldered nipple pivoting slightly within the rim to adjust for slight angular adjustments within the rim, and the spoke extending away at an angle from the nipple in the rim; 
         FIGS. 8 and 9  are a cross-sectional view of an alternative embodiment of wheel with high strength flexible spokes of the present invention showing cross-sectional portions of the rim and hub, and showing a spherical nipple sized to be fully received within the rim and formed with a keyway to receive a key when secured during assembly of the wheel, and with the spherical nipple rotating within the rim to accommodate the angular positioning of a spoke extending away from the rim with little or no angular change with the tube head and spoke; and 
         FIG. 10  is an exemplary embodiment of a key for tightening the high strength flexible spokes of the present invention, and includes a handle having a shaft leading to a head formed with a number of keys sized and positioned to cooperatively engage the keyways on nipples of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a side view of a first preferred embodiment of the wheel with flexible spokes of the present invention is shown and generally designated  100 . In  FIG. 1 , the side of wheel  100  facing the viewer can be referred to as the right side of the wheel  100 . The side of wheel  100  opposite the right side can be referred to as the left side of the wheel  100 . The wheel  100  has a wheel axis  104 , and a rim  110  which has an inner perimeter  112  and an outer perimeter  114 . 
     Still referring to  FIG. 1 , with reference to  FIG. 3 , distributed symmetrically along inner perimeter  112  are spoke holes  120 . Each spoke hole  120  has a spoke hole width  122 . Along the outer perimeter  114  are nipple access holes  124  (not visible in  FIG. 1 ), one nipple access hole  124  adjacent each spoke hole  120 . Wheel  100  further includes a hub  130  having a right flange  132  and a left flange  134  (not visible, behind right flange  132 ). Each flange  132  and  134  has an inner surface  136  and an outer surface  138 . In each flange  132  and  134  are flange holes  140 , each flange hole  140  corresponding to a unique spoke hole  120 . Each flange hole  140  has an inner opening  142  in the corresponding inner surface  136 , and an outer opening  144  in the corresponding outer surface  138 . Hub  130  also has a barrel  148  which receives an axle of a bicycle. 
     Wheel  100  further includes non-rigid spoke members, or spokes  150 . Each spoke  150  has non-rigid fibers  152  (not visible this Figure) covered by a jacket  154  having an inner diameter  156  (not visible) and an outer diameter  158  which is also the width  158  of spoke  150 . Each spoke  150  has a length  160 . Fibers  152  are substantially continuous along the length  160  of spoke  150 . Alternatively, one or more of fibers  152  may be less than continuous along the length of spoke  150 . 
     Each spoke  150  has an inner end  162  adjacent rim  110  hub  130 , and an outer end  164  adjacent rim  110 . Each spoke  150  has a tube  170  about its outer end  164 , and each tube  170  is formed with a tapered bore  171  opening away from the midpoint of the spoke. Each tube  170  is affixed to its corresponding outer end  164  by inserting the fibers  152  into the tube, and filling the tube with epoxy  175 . Once hardened, the epoxy  175  and fibers  152  form a wedge within the tapered bore  171  such that any tension on the spoke draws the hardened wedge against the taper thereby securing the fiber within the tube. Alternatively, tube  170  may be affixed to outer end  164  by any other material of similar strength. 
     Tube  170  may be equipped with a hexagonal, reinforced head  165  which provides for added strength at the hub-end of the tube  170 . This is helpful in preventing breakage for a non-axial tension on spoke  150 , and facilitates the tightening of spoke  150 . 
     Each tube  170  has a tube axis  172  and external spoke threads  174 . Each spoke  150  also has an anchor (or eyelet or ferrule)  180  about its inner end  162 . Each anchor  180  is formed with a tapered bore  181  opening away from the midpoint of the spoke. Each anchor  180  is affixed to its corresponding inner end  162  by inserting the fibers into the anchor, and filling the tapered bore  181  with epoxy  163 . Once hardened, the epoxy and fibers form a wedge within the tapered bore  181  formed in the anchor  180  such that any tension on the spoke draws the hardened wedge against the taper thereby securing the fiber  150  within the anchor  180 . Alternatively, anchor  180  may be affixed to inner end  162  by any other material of similar strength. 
     Each flange hole  140  is wider than spoke  150  but narrower than anchor  180 , such that tube  170  about outer end  164  can be passed into inner opening  142  and out of outer opening  144 , and such that the rest of spoke  150  can then be passed through flange hole  140  until anchor  180  comes into contact with inner surface  136  around inner opening  142 , which causes inner end  162  to be retained in flange hole  140  by anchor  180 . 
     Wheel  100  also includes nipples  190 . One nipple  190  is shown in  FIG. 1  in broken line, inside rim  110 . There is a nipple  190  between each spoke hole  120  and its corresponding nipple access hole  124 . Each nipple  190  has a nipple opening  192 , nipple threads  194  inside nipple opening  192 , a collar  196 , and a nipple head  198 . Once each spoke  150  is passed through flange hole  140  until anchor  180  comes into contact with inner surface  136  around inner opening  142 , tube  170  is positioned and threaded into the corresponding nipple  190  via inter-engagement of spoke threads  174  with nipple threads  194 . This causes tube  170  to be retained in nipple  190  such that tube axis  172  is perpendicular to wheel axis  104  (shown in  FIG. 1 ). The retention of tube  170  in nipple  190 , and of inner end  162  in flange hole  140  by anchor  180 , causes spoke  150  to be held taut between rim  110  and hub  130 . 
       FIG. 1  shows eight (8) spokes  150  attached to right flange  132 , and eight (8) spokes  150  attached to left flange  134  (not visible, behind right flange  132 ), for a total of sixteen (16) spokes  150 . Wheel  100  may alternatively have more or fewer than sixteen (16) spokes  150 . For example, wheel  100  may have twelve (12) spokes  150 , six (6) spokes  150  attached to each of flanges  132  and  134 . While it is also possible to have different numbers of spokes  150  attached to each of flanges  132  and  134 , having the same number of spokes attached to each of flanges  132  and  134  balances the load on the flanges  132  and  134 . 
       FIG. 2  is a rear view of hub  130 .  FIG. 2  shows the angle that one of the spokes  150  is attached to right flange  132 , and the angle that one of the spokes  150  is attached to left flange  134 . In  FIG. 2 , the right side of wheel  100  is on the right side of  FIG. 2 , and the left side of wheel  100  is on the left side of  FIG. 2 . Broken line  230  in  FIG. 2  represents a plane  230  that bisects wheel  100  between the right side and left side of wheel  100 . Plane  230  is perpendicular to wheel axis  104 . Each outer surface  138  has the shape of a conical section that has an angle  240  to wheel axis  104 . Each spoke  150  extends perpendicularly from the corresponding outer surface  138 . Therefore, each spoke  150  extends from outer surface  138  at an angle  250  to plane  230 . This means that the magnitude of angle  260  between spoke  150  attached to right flange  132  and spoke  150  attached to left flange  134 , is twice the magnitude of angle  250 . 
       FIG. 3  shows a partial cross-sectional detail view of a spoke  150  with its inner end  162  retained in flange hole  140  by anchor  180 , and tube  170  about to be received in nipple  190  in rim  110 .  FIG. 3  shows how nipple  190  is retained in spoke hole  120 . Spoke hole width  122  allows the portion of nipple  190  around nipple opening  192  to pass through spoke hole  120 , but does not allow collar  196  to pass through spoke hole  120 , such that nipple is retained in spoke hole  120  by the tension of spoke  150  on nipple  190  once tube  170  is threaded into nipple  190 .  FIG. 3  also shows spoke threads  174  which inter-engage with nipple threads  194  to thread tube  170  into nipple  190 . With tube  170  retained in nipple  190 , tube axis  172  is perpendicular to wheel axis  104  (not shown) and intersects the corresponding spoke hole  120 . Spoke holes  120  lie in plane  230 . While spoke holes  120  may alternatively be adjacent plane  230 , spoke holes  120  being in plane  230  causes the forces of spokes  150  to be placed on rim  110  where plane  230  intersects rim  110 , which is the middle of the inner perimeter  112  of rim  110 . With spoke holes  120  in plane  230 , and each tube  170  received in the corresponding nipple  190 , tube axis  172  also lies in plane  230 . 
     In  FIG. 3 , tube axis  172  coincides with the broken line representing plane  230 . However, because each spoke  150  extends at angle  250  to plane  230 , each spoke  150  extends from its tube  170  at angle  250  to tube axis  172 . This means that there is a bend in spoke  150  at an angle  250  at the point  320  where spoke  150  protrudes from tube  170 . With steel spokes, such a bend would weaken the spoke and ultimately cause the spoke to fail. However, with spokes  150 , such a bend does not damage spokes  150 , because fibers  152  are flexible and resilient yet strong such that spokes  150  retain their integrity and strength even when bent under tension in the manner described. Therefore, spokes  150  can bend without weakening or failing. Furthermore, each of spokes  150  is three times as strong, and weighs half as much, as a steel spoke that would otherwise be used in its place. This allows the width  158  of each of spokes  150  to be greater than that of a steel spoke that would be used in its place. In the alternative, the width  158  of each spoke  150  may be less than or equal to the width of a steel spoke that would be used in its place; the strength of each of spokes  150  may be greater or less than three times that of a steel spoke that would be used in its place; and the weight of each of spokes  150  may be greater or less than half that of a steel spoke that would be used in its place. 
     Rim  110 , hub  130 , tube  170 , anchor  180  and nipple  190 , in a preferred embodiment, are made of aluminum. Alternatively, any of rim  110 , hub  130 , tube  170 , anchor  180  or nipple  190  may be made of any other material of comparable strength. In a preferred embodiment of the present invention, fibers  152  are a bundle of thermotropic liquid crystal fibers that exhibit high strength, low creep, and weather resistance. For instance, the fibers could be a PBO fiber such as Zylon ®, a strong yet lightweight fiber, available from Toyobo. Alternatively, fibers  152  may be made of any other material having comparable weight and strength. Jacket  154  is made of Rilsan ®, a high-performance polvamide. Alternatively, jacket  154  may be made of any other material having comparable weight and strength. Each nipple access hole  124  allows access to nipple head  198  so that it can be turned to facilitate the threading of nipple  190  onto tube  170 . For instance, a hexagonal head nut-driver may be positioned over nipple  190  and rotated to tighten spoke  150  in place. 
       FIG. 4  shows a cross-sectional detail view of the inside of a spoke  150 , showing the fibers  152 , and inner diameter  156  of jacket  154 . Fibers  152  are gathered in forty-four (44) bundles  410  of nine-hundred ninety-six (996) filaments each bundle, for a total of 43,824 filaments in spoke  150 . This great number of filaments is one factor contributing to the great strength of spoke  150 , while minimizing the weight of spoke  150 . Spoke  150  has a breaking strength of 3,600 pounds. Alternatively, the number of bundles  410  may be greater or less than 44; the number of filaments in each bundle  410  may be greater or less than 996; and the breaking strength of spoke  150  may be greater or less than 3,600 pounds. 
     Referring to  FIG. 5 , a cross-sectional view of the first preferred embodiment of the wheel with flexible spokes of the present invention showing cross-sectional portions of the rim and hub is shown. As can be appreciated from  FIG. 5 , the width of rim  110  is just slightly wider than the width of nipple  190 . As a result, it is necessary that the nipple be aligned so that the tube extends radically inward from rim  110 . Because of this positioning, it is important that spoke  150  be flexible as it leaves tube  190  so as to accommodate angle  250  without any decrease in strength and durability. Due to the number of fiber strands contained within spoke  150 , there is no noticeable decrease in strength despite the off-axis tension. 
     When tension is applied to spoke  150 , collar  196  strikes the inside surface of rim  110  and maintains the nipple, and corresponding sleeve, in its perpendicular arrangement. 
     Referring now to  FIGS. 6 through 9 , a number of alternative embodiments of the wheel with high strength flexible spokes of the present invention are shown and include variations on the nipple and rim. 
     Referring initially to  FIG. 6 , the wheel with high strength flexible spokes of the present invention is shown and includes a shortened nipple generally designated  450 . Shortened nipple  450  is sized to be fully received within the rim  110 . Nipple  450  includes a nipple head  452  and a collar  460  sized to rest against the interior of the rim  110  and allow nipple opening  456  to pass through spoke hole  120 . Shortened nipple  450  is formed with a threaded bore  454  passing longitudinally along axis  172  from nipple opening  456 . Threaded bore  454  is sized to threadably receive head tube  170 . 
     Shortened nipple  450  is formed with a keyway  462  to receive a key when secured during assembly of the wheel. More specifically, nipple head  452  is formed with a pattern of keyways  462  to receive a correspondingly shaped key to maintain the rotational position of nipple  450  along axis  172  during the installation of spoke  150 . By inserting a key into keyways  462 , the nipple  450  may be held in place while head tube is rotated such that head tube threads  174  enter nipple  450 . 
     As shown in  FIG. 6 , spoke  150  may extend away from axis  172  by an angle  250  as described in conjunction with alternative embodiments. 
     Referring now to  FIG. 7 , a cross-sectional view of an alternative embodiment of the wheel with high strength flexible spokes of the present invention is equipped with a shouldered nipple generally designated  480 . Shouldered nipple  480  includes an insert  482  having a diameter  484  which is slightly less than the diameter of spoke hole  120  of rim  110 . Shoulder  484  is larger in diameter than insert diameter  484  such that the insert shoulder  484  rests on the inside surface of rim  110 . 
     Shouldered nipple  480  is formed with a threaded bore  488  which passes from nipple opening  483  through to nipple head  486 , and includes threads  492  matching threads  174 . Threaded bore  488  is sized to threadably receive threads  174  on tube head  170  during the assembly of the wheel with high strength flexible spokes of the present invention. 
     From  FIG. 7  it can been seen that shoulder  484  is rounded and corresponds with a mating surface  494  on rim  110  such that the axis  172  of nipple  480  may vary slightly within rim  110 . Specifically, the mating surface  494  allows the shouldered nipple  480  to pivot slightly within the rim  110  to accommodate slight angular adjustments within the rim, such that the spoke  150  can extend away at an angle  250  from the nipple  480  and rim  110 . 
     A number of keyways  490  are formed in nipple head  486  such that a corresponding key (not shown) can be inserted into keyways  490  to maintain the rotational position of nipple  480  during the threading of tube head  170  into threaded bore  488 , and when tightening the spoke  150  using hexagonal head  165 . Also, nipple  480  is sized to be fully received within access hole  124  in rim  100 . 
     Referring now to  FIGS. 8 and 9 , cross-sectional views of an alternative embodiment of wheel with high strength flexible spokes of the present invention showing cross-sectional portions of the rim and hub, and showing a spherical, or rounded, nipple generally designated  500 . Rounded nipple  500  is formed with a spherical or near spherical body  502  having a bore  506  along axis  172  and formed with threads  504  from inlet  506  through end  510 . 
     Rim  110  is formed with nipple seat  508  that is shaped to receive rounded nipple  500  to retain nipple  500  in position along axis  172  of rim  100 .  FIG. 9  depicts the insertion of a spoke  150  into rounded nipple  500  by threadably rotating spoke  150  along axis  518  and advancing the spoke  150  in direction  514 . 
     Rounded nipple  500  is formed with a number of keyways  512  sized to receive a key, such as the key  550  shown in  FIG. 10 , having a handle  552  and a shaft  554  leading to a head  556  formed with keys  558  positioned and sized to correspond to keyways  512  on rounded nipple  500 . It is to be appreciated that the number, size, positioning of the keys  558  may vary to accommodate keyway size, shapes, and patterns of nipples described herein. Head  556  of key  550  is formed to have a diameter  560  that is less than the diameter of access hole  124 . Accordingly, key  550  can be inserted into rim  110  during the wheel assembly process to engage keys  558  into keyways  512  to maintain the rotational position of rounded nipple  500  as head tube  170  is threaded into nipple  500 . 
     Also from  FIG. 9 , the rotation of rounded nipple  500  within rim  110  is shown. Rounded nipple  500  rotates within the rim  110  to accommodate the angular positioning of a spoke  150  extending away from the rim  110  with little or no angular change with the tube head and spoke. Specifically, rounded nipple  500  rests against nipple seats  508  and can rotate about a center of rotation  522  such that the axis  518  of tube head  174  can move within range  520 . This range  520  allows the spoke  150  to maintain a relatively straight line between tube head  174  and anchor  180  of hub  130 . This straightness along axis  518  provides additional strength as all fibers  152  within spoke  150  are stressed similarly along the longitudinal axis of the spoke. 
     Referring now to  FIG. 10 , an exemplary embodiment of a key tool for tightening the high strength flexible spokes of the present invention is shown and generally designated  550 . Key tool  550  includes a handle  552  having a shaft  554  leading to a head  556  formed with a number of keys  558  sized and positioned to cooperatively engage the keyways on nipples of the present invention. The diameter  560  of head  556  is intended to be sized to be insertable through the access hole  124  in the rim  110  as disclosed herein to engage the nipples described to facilitate the high strength flexible spokes of the present invention. It is to be appreciated that the key tool  550  is shown in  FIG. 10  to have four keys  558  which, in a preferred embodiment, correspond to the inserts shown to have four keyways. It is to be appreciated further, that the number, size and positioning of keys  558  can vary to accommodate a nipple formed with different configurations of keyways. 
     While the wheel with high strength flexible spokes of the present invention as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of preferred and alternative embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.