Abstract:
An adjustable axle assembly for use with a wheel comprises a first hub defining a first aperture in an off-centered position so geometric centers of the first aperture and the first hub are eccentrically located, the first aperture adapted to receive an axle; a second hub defining a second aperture in an off-centered position so the geometric centers of the second aperture and the second hub are eccentrically located, the second aperture adapted to rotationally receive the first hub; and a locking assembly coupling and controlling the rotational movement of the first hub and the second hub. The second aperture of the second hub includes a plurality of indents formed on the inner surface of the second hub separated by a predetermined angle for releasably engaging the locking assembly, wherein the plurality of indents represents an angle of eccentric rotation of the wheel. At least one of the plurality of indents positions the first hub with respect to the second hub to place the axle in a geometric center of the second hub to provide a concentric rotation of the wheel.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an axle structure for a riding apparatus, such as a bicycle, and more particularly, an axle assembly adapted to be adjustable to offset the position of the axle from the geometric center of the wheel. 
     2. Discussion of the Related Art 
     Although the primary mode of ground transportation is the automobile, the bicycle continues to be a popular mode of transportation, particularly for recreational purposes. A typical bicycle enables a rider to obtain relatively high speeds, which is advantageous while traversing flat terrain or going downhill. With the advent of mountain bicycles, riders can enjoy such bicycles in a rugged mountain terrain with bumps and pot holes. 
     A bicycle axle is a major driving part to a bicycle since it transfers the force received from two cranks to a driving wheel which then drives the bicycle. A conventional bicycle has a concentric wheel with an axle in the center thereof to drive the bicycle. The position of the axle cannot be adjusted. 
     Known bicycle axle structure includes U.S. Pat. No. 5,553,878 to Davignon et al. The device disclosed in the Davignon patent is directed to an adjustable riding toy in both bicycle and tricycle forms. The bicycle is equipped with at least one wave ride wheel allowing a rider to change between a smooth ride and an up-and-down ride. This is accomplished by providing a wheel having a plurality of axle apertures therein. By placing the axle in one of the axle apertures, the wheel of the bicycle can be of a concentric shape or an eccentric shape. 
     While the above device fulfills its particular objectives and requirements, one disadvantage is that the axle and wheel assembly has to be physically disassembled from the bicycle frame. In particular, the axle has to be removed from one axle aperture of the wheel and then replaced into another axle aperture prior to re-fitting with the bicycle frame. This disassembling and re-assembling requires mechanical tools and effort and is therefore very cumbersome and discouraging. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to an axle structure or assembly of a wheel that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
     An object of the present invention is to provide an adjustable axle assembly for adjustably shifting the position of the axle with respect to a wheel to provide eccentric rotation of the wheel. 
     Another object of the present invention is to provide a simple and easy way to adjust the axle position without using any tools. 
     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an adjustable axle assembly for use with a wheel comprises a first hub defining a first aperture in an off-centered position so geometric centers of the first aperture and the first hub are eccentrically located, the first aperture adapted to receive an axle; a second hub defining a second aperture in an off-centered position so the geometric centers of the second aperture and the second hub are eccentrically located, the second aperture adapted to rotationally receive the first hub; and a locking assembly coupling and controlling the rotational movement of the first hub and the second hub. Preferably, a roller bearing is disposed in the second aperture of the second hub between the first hub and second hub to assist rotation of the first hub. 
     According to one aspect of the preferred embodiment, the locking assembly is disposed in the first hub and includes a lock protruding from the first hub to releasably engage the second hub. The locking assembly includes a platform secured to an inner surface of the first hub; at least one alignment rod extending from the platform to align or guide the movement of the lock; and a spring disposed in surrounding relation to the alignment rod, wherein the spring biases the lock to a locking position to prevent the first hub from rotating with respect to the second hub. 
     According to another aspect of the preferred embodiment, the first hub includes a slit, wherein a wing of the lock protrudes therethrough and is coupled to a lever to releasably control the rotation of the first hub with respect to the second hub. Moreover, the first hub includes right and left plates, each plate defining an aperture adapted to receive the axle, the right and left plates being fastened together from opposite sides of the second aperture of the second hub. 
     According to another aspect of the present invention, the second aperture of the second hub includes a plurality of indents formed on the inner surface of the second hub separated by a predetermined angle for releasably engaging the locking assembly, wherein the plurality of indents represents an angle of eccentric rotation of the wheel. At least one of the plurality of indents positions the first hub with respect to the second hub to place the axle in a geometric center of the second hub to provide a concentric rotation of the wheel. 
     In another embodiment of the present invention, a mobile apparatus comprises at least one wheel having a rim with a geometric center; a first hub defining a first aperture in an off-centered position so geometric centers of the first aperture and the first hub are eccentrically located, the first aperture adapted to receive an axle; a second hub defining a second aperture in an off-centered position so the geometric centers of the second aperture and the second hub are eccentrically located, the second aperture adapted to rotationally receive the first hub, wherein the second hub has the same geometric center as the rim; and a locking assembly coupling and controlling the rotational movement of the first hub and the second hub. Preferably, a roller bearing is disposed in the second aperture of the second hub between the first hub and second hub to assist rotation of the first hub. 
     According to one aspect of the preferred embodiment, the locking assembly is disposed in the first hub and includes a lock protruding from the first hub to releasably engage the second hub. The locking assembly includes a platform secured to an inner surface of the first hub; at least one alignment rod extending from the platform to align the movement of the lock; and a spring disposed in surrounding relation to the alignment rod, wherein the spring biases the lock to a locking position to prevent the first hub from rotating with respect to the second hub. 
     According to another aspect of the preferred embodiment, the first hub includes a slit, wherein a wing of the lock protrudes therethrough and is coupled to a lever to releasably control the rotation of the first hub with respect to the second hub. Moreover, the first hub includes right and left plates, each plate defining an aperture adapted to receive the axle, the right and left plates being fastened together from opposite sides of the second aperture of the second hub. 
     According to another aspect of the present invention, the second aperture of the second hub includes a plurality of indents formed on the inner surface of the second hub separated by a predetermined angle for releasably engaging the locking assembly, wherein the plurality of indents represents an angle of eccentric rotation of the wheel. At least one of the plurality of indents positions the first hub with respect to the second hub to place the axle in a geometric center of the second hub to provide a concentric rotation of the wheel. 
     The second hub is preferably connected to the rim through a plurality of spokes. Alternatively, the rim of the wheel can be an outer circumferential surface of the second hub. 
     According to another embodiment of the present invention, a method of manufacturing an adjustable axle assembly for use with a wheel is provided. The method comprises the steps of providing a first hub defining a first aperture in an off-centered position so geometric centers of the first aperture and the first hub are eccentrically located, the first aperture adapted to receive an axle; providing a second hub defining a second aperture in an off-centered position so the geometric centers of the second aperture and the second hub are eccentrically located, the second aperture adapted to rotationally receive the first hub; and providing a locking assembly in the first hub for releasably coupling and controlling the rotational movement of the first hub and the second hub. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide a further explanation of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     FIG. 1 illustrates a schematic view of a bicycle using an adjustable axle assembly according to a preferred embodiment of the present invention; 
     FIG. 2 illustrates a schematic view of a fixed exercise bicycle using the adjustable axle assembly according to the preferred embodiment of the present invention; 
     FIG. 3 illustrates an elevation view of a bicycle wheel using the adjustable axle assembly; 
     FIG. 4 illustrates a disassembled view of the adjustable axle assembly according to the present invention; 
     FIG. 5 illustrates a cross-sectional view with respect to line  5 — 5  of FIG. 3; 
     FIG. 6 illustrates a cross-sectional view with respect to line  6 — 6  of FIG. 4; 
     FIG. 7A illustrates a cross-sectional view with respect to line  7 — 7  of FIG. 4 with an axle in a concentric position; and 
     FIG. 7B illustrates a cross-sectional view with respect to line  7 — 7  of FIG. 4 with an axle in an eccentric position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings, and in particular to FIGS. 1-7B thereof, an adjustable axle assembly embodying the principles and concepts of the present invention will be described. 
     FIG. 1 illustrates a schematic view of a bicycle using an adjustable axle assembly  10  according to a preferred embodiment of the present invention. Referring to FIG. 1, the bicycle  200  embodiment of the present invention will be used to illustrate one preferred embodiment. However, many aspects of the invention may be adapted for use on riding or other vehicles with wheels. For example, the adjustable axle assembly  10  according to the preferred embodiment of the present invention may be used on a tricycle or any vehicles requiring wheels, including toy cars, carts and bicycles. When used in a bicycle  200 , the axle assembly  10  may be used for a front wheel  202  and/or a rear wheel  204 . 
     The bicycle  200  comprises a body  210 , a front wheel  202  and a rear wheel  204 . The construction of the body is preferably from a suitable molded metal material and is generally known in the industry. However, the bicycle  200  may be constructed from any other suitable materials, such as various plastic composites. The front and rear wheels  202  and  204  are rotatably connected to the body  210 , to allow the bicycle  200  to roll. 
     FIG. 2 illustrates a schematic view of a fixed exercise bicycle  300  using the adjustable axle assembly  10  according to the preferred embodiment of the present invention. Since the front end of the exercise bicycle  300  is fixedly attached to a platform  302 , only the rear wheel  304  is equipped with the axle assembly  10 . The rear wheel  304  is placed on a roller assembly  306  for support and stationery ride during exercise. 
     By simply rotating a first hub  110  with respect to a second hub  120  using a lever  110  extending from the first hub  110 , the position of the axle with respect to the rim  205  of a wheel is adjusted, giving a rider an eccentrical movement of the wheel. In other words, because the axle is not located at a geometric center of the wheel  204 , the bicycle  200  or the exercise bicycle  300  is provided with an up-and-down and/or undulating motion caused by an eccentric rotation of the wheel. The position of the first hub  110  with respect to the second hub  120  determines the angle of eccentric rotation of the wheel. When both wheels  202  and  204  in the bicycle  200  have the axle assembly  10 , then the eccentric movement of each wheel can be independently controlled as the rider desires. 
     The adjustable axle assembly  10  is shown generally in FIGS. 3-7B. FIG. 3 illustrates an elevation view of a bicycle wheel  204  using the adjustable axle assembly. For purposes of brevity, only the rear wheel  204  with the axle assembly  10  will be used to illustrate the present invention. 
     The wheel  204  includes a rim  205  connected to the axle assembly  10  through a plurality of spokes  206 . In particular, the spokes  205  connect the second hub  120  of the axle assembly  10  with the rim  205 . Alternative to the spokes  206  which are made with rods or bars, the wheel  204  may be equipped with a solid and plane spoke which completely fills the region between the rim  205  and the second hub  120 . A detailed explanation of the axle assembly  10  is provided below. 
     FIG. 4 illustrates a disassembled view of the adjustable axle assembly  10  according to the present invention. The first hub  110  and the second hub  120  of the axle assembly  10  according to the preferred embodiment are rotatably disposed with each other. The first hub  110  is disposed in a geometrically off-centered position with respect to the second hub  120 . The first hub  110  is adapted to receive an axle  112  which is mounted on a fork  240  shown in FIG.  1 . The position of the axle  112  is also geometrically offset from the center of the first hub  110 . The first hub  10  includes two matching sets of cylindrical right and left plates  142  and  144 . The right plate  142  and the left plate  144  are joined with each other using any suitable process. In the preferred embodiment, a set of screws  222  are used to fasten the plates  142  and  144  together. 
     The left plate  144  of the first hub  110  is constructed to include a step-like structure having an inner cylindrical member having different diameters. Preferably, the left plate  144  has a first inner cylinder  145  and a second inner cylinder  146 , both of which are integrally attached to a left cover  147 . Preferably, the left cover  147 , first inner cylinder  145  and second inner cylinder  146  are made of metal or other suitable material, such as plastic, known to one of ordinary skill in the art and are formed as a single piece. The first inner cylinder  145  is adapted to fit in the first aperture  122  defined by the second hub  120 . The second inner cylinder  146  is adapted to fit in the second aperture  123  defined by the second hub  120 . The first and second apertures  122  and  123  are concentric and their centers are offset from the center of the second hub  120 . The description of the right plate  142  of the first hub  110  is identical to the left plate  144  above and will not be repeated. 
     The right and left plates  142  and  144  each has an axle aperture  150  adapted to receive an axle  112 . Surrounding the axle aperture  150  is a plurality of holes  151  for aligning and fastening with the holes  113  formed in a collar member of the axle  112 . Preferably, the axle  112  is disposed between the right and left plates  142  and  144  and is fastened with screws through the holes  151  in the right and left plates  142  and  144  and the holes  113  in the collar member of the axle  112 . 
     Referring to FIGS. 4,  5  and  6 , the first hub  110  also includes a locking assembly  170  used for locking the position of the first hub  110  with respect to the second hub  120 . The locking assembly  170  includes a lock  172 , a platform  174 , a spring  176  for biasing the lock with respect to the platform  174  and a plurality of alignment rods  178  for aligning the lock  172 . In the preferred embodiment, the platform  174  is fixedly attached to approximately the center of the inner surface of the left plate  144 . Alternatively, the platform  174  may be fixed to the inner surface of the right plate  142  of the first hub  110 . Vertically extending from the platform  174  are three alignment rods  178 , which are better illustrated in FIGS. 5 and 6. The alignment rods  178  may be screwed into the platform  174 , or alternatively, may be molded with the platform  174  as a single piece component. 
     The lock  172  is a Greek letter “π” shaped part which is inserted into a slit  154  defined in both right and left plates  142  and  144 . The lower portion of the lock  172  has receptacles  173  for receiving three alignment rods  178 . Preferably, the lock  172  has a spaced middle portion for accommodating the spring or coil  176 . The spring  176  is used for biasing the lock  172  away from the platform  174 . The lock  172  is arranged such that its vertical movement is limited by the longitudinal length of the slit  154  and the location of the platform  174 . To assist the sliding of the lock  172  in the slit  154 , a lever  102  is attached to one end of the wing  179 , as shown in FIG.  5 . The components of the locking assembly  170  are preferably made of suitable metal or metal composites or other materials, such as plastic, known to one of ordinary skill in the art. 
     In an alternative embodiment, the lock  172  may have a shape which has only one wing  179  extending through a slit  154  formed only on the left plate  144  of the first hub  110  since the lever  102  is connected only to that wing  179  as shown in FIG.  4 . When such lock  172  is used, a slit  154  formed in the right plate  142  of the first hub  142  is obviously not necessary and can be eliminated. 
     The locking assembly  170  can be configured to be placed in the second hub  120  in lieu of the first hub  110 . In such an embodiment, the indents are formed in the circumference of the first hub  110 , while the lock is movably extending from the second hub  120  to control the rotational position or the angle of eccentric rotation of the first hub  110  with respect to the second hub  120 . 
     Referring to FIG. 4, the second hub  120  has a first aperture  122  sized to receive the first inner cylinder  145  of the first hub  110 . The second hub  120  also has a second aperture  123  sized to receive the second inner cylinder  146 . In the preferred embodiment, the first aperture  122  is slightly larger in diameter to allow the first hub  110  to rotate therein. In particular, the first aperture  122  is sufficiently large to receive a roller bearing  160  which is placed in surrounding relation to the first inner cylinder  145  of the first hub  110 . The presence of the roller bearing  160  reduces friction between the first and second hubs  110  and  120 . Alternative to the roller bearing  160 , other suitable bearing assembly may be used. In addition, a lubricating material, such as lubricating oil or power, may replace the roller bearing  160 . 
     The second hub  120  is also equipped with a plurality of indents  124  for adjusting the rotating position or the angle of eccentric rotation of the first hub  110 . The indents  124  are used to offset the position of the first hub  110  with respect to the second hub  120  which, in effect, causes the position of the axle  112  to shift with respect to the geometrical center of the second hub  120 . The angle between the first indent and the fourth indent is about 70-100 degrees, preferably 85 degrees, to provide a varying degree of eccentric ride. In the preferred embodiment, there are four indents  124  for offsetting an axle position. 
     Referring to FIGS. 5 and 6, the lever  102  for controlling the movement of the lock  172  is slidably attached to a bracket  185  which is securely mounted on the outer surface of the first hub  110 , preferably immediately above the hole  150  receiving an axle  112 . The bracket  185  has two holes for receiving rods that form the lever  102 . Because the lever  102  is pivotally connected to the wing  179  of the lock  172 , it does not need to be secured to the first hub  110 . 
     FIGS. 7A and 7B illustrate a cross-sectional view with respect to line  7 — 7  of FIG.  4 . FIG. 7A illustrates an axle in a concentric position with respect to the second hub  120 , and FIG. 7B illustrates an axle in an eccentric position. When the lock  172  is used to position the first hub  110  to an indent designated as “0” in the second hub  120 , the axle  112  is placed in a geometric center of the second hub  120 . However, when the lock  172  is used to position the first hub  110  to an indent designated anything other than “0”, as shown in FIG. 7B, in the second hub  120 , the position of the axle  112  is offset from the geometric center of the second hub  120 . The indent designated with a higher number, such as “3,” signifies a larger offset from the geometric center of the second hub  120  and provides a greater eccentric rotation of the wheel. 
     FIG. 5 illustrates a cross-sectional view with respect to line  5 — 5  of FIG.  3 . In particular, FIG. 5 generally illustrates an internal layout and components of the adjustable axle assembly  10  according to the present invention. As shown, the first hub  110  is placed in a geometrically eccentric position with respect to the second hub  120 . The axle  112  is securely attached to the first hub  110  using fasteners, such as screws. However, by adjusting the position of the first hub  110  with respect to the second hub  120  using the lock  172 , the position of the axle  112  is geometrically offset with respect to the second hub  120 . 
     The materials for the first hub  110  and the second hub  120  can be made with a light weight, rigid material, such as aluminum, plastic, or other suitable materials known to one of ordinary skill in the art. The second hub  120  may be formed as an integral piece of the rim  205 , as shown in FIG. 3, when both the rim  205  and the second hub  120  are made with the same material. In certain instances, the second hub  120  may be constructed to serve as a rim of a wheel. 
     Assembly of the adjustable axle assembly  10  according to the present invention is as follows and is described in reference to FIG.  4 . First, the lock assembly  170  is placed in the first hub  110  between the right and left plates  142  and  144 . This is accomplished by mounting the platform  174  with alignment rods  178  to the left plate  144 , placing a spring  176  in surrounding relation to the middle alignment rod and then placing the lock  172  onto the alignment rods  178  so as to slidably move thereon. The wings  179  of the lock  172  are inserted into slits  154  defined by the first hub  110 . Thereafter, or prior to the placement of the lock assembly  170 , an axle assembly  112  is placed between the right and left plates  142  and  144  of the first hub  110  and secured thereto. 
     The right and left plates  142  and  144  are each fitted with a roller bearing  160  and placed on opposite sides of the second hub through the aperture  122  defined by the second hub  120 . When placing the left plate  144  with the lock assembly  170 , the lock  172  is positioned in one of the indents  124  in the second hub  120 . Thereafter, the right and left plates  142  and  144  are fastened together using fasteners, such as screws, to complete the first hub  110  and to rotatably mount the first hub  110  in the second hub  120 . The lever  102  is then attached to the wing  179  using a fastener. The offset angle of the first hub  110  with respect to the second hub  120  is adjusted using the lock  170  by controlling the lever  102 . Since the second hub  120  is attached to the spokes  206  extending from the rim  205  of a wheel, the wheel is now complete and ready to be mounted in a bicycle. 
     A method of using the adjustable axle assembly  10  according to the present invention will now be discussed in reference to FIGS. 1,  2 ,  7 A and  7 B. Once the front and rear wheels  202  and  204  are installed in the body  210  of the bicycle  200 , the bicycle is now read for use. By pushing down on the lever  102 , which in effect pushes the lock  172 , the lock  172  disengages one of the indents  124  of the second hub  120 . Since there is no longer a locking mechanism to hinder the movement of the first hub  110 , the first hub  110  can now be rotated with respect to the second hub  120  to set a desired angle of eccentric rotation. When the first hub  110  is rotated to be in the indent designated as “0,” the axle  112  is right at the geometric center of the wheel and therefore a level ride occurs. The adjustable axle assembly of both the front and rear wheels  202  and  204  can be adjusted to maintain a level ride. 
     When a rider desires a more bumpy or undulating ride, the position of the first hub  110  is adjusted with respect to the second hub  120  by controlling the lever  102 . When there are four axle positions for each wheel, there are a total of sixteen different riding positions. The eccentric rotation of the wheel can be adjusted while the bicycle is stopped and the rider is seating on a bicycle seated by simple sliding the lever  102  to control the position of the lock  172 . 
     The same use is applied when the wheel, using the adjustable axle assembly  10  of the present invention, is used in an exercise bicycle shown in FIG.  2 . The adjustment of the location of the axle provides the rider with a more enjoyable and undulating ride which is not available in a regular bicycle. 
     When the adjustable axle assembly  10  according to the present invention is used in a wheel that has no spokes, the second hub  120  can be configured to serve as a rim for receiving a tire thereon. For example, when the adjustable axle assembly  10  is configured to be used in a toy pull cart or go cart, the second hub  120  becomes the rim of the wheel for receiving the tire. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.