Abstract:
An apparatus and method for removably holding an axle includes an axle attachment which is removably attachable to an end of the axle. A threaded shaft is coupled to the axle attachment, and a latch is selectively engageable with the threads of the shaft. A crank is coupled to the shaft, and rotation of the crank results in advancement of the axle attachment towed the end of the axle, to clamp the axle between the axle attachment and a centering apparatus engageable with the opposite end of the axle. The latch is movable to a release position in which the latch is disengaged from the threads of the shaft. A spring bears against the crank so as to bias the axle attachment away from the end of the axle, and the spring functions to disengage the axle attachment from the end of the axle when the latch is moved to its release position. The centering apparatus is movable to varying positions so as to accommodate varying axle lengths and to provide proper centering of the axle.

Description:
BACKGROUND 
     The present invention relates generally to a wheel attachment, and more particularly to attaching a wheel of a bicycle to a stationary trainer. 
     For many years, bicycle enthusiasts have used bicycle trainers to convert their bicycles for stationary (often indoors) riding. Rather than ride through inclement weather, the cyclist can use the trainer to ride indoors and obtain an aerobic, cardiovascular workout. Bicycle trainers also obviate the need for purchasing a separate stationary bicycle for those persons who want to occasionally workout while, for example, reading or watching television. A bicycle trainer should be easy to use and, to the extent possible, simulate bicycle riding on the open road. 
     Typical bicycle trainers attach a rear wheel of a bicycle to a resistance unit mounted in a frame. The resistance unit couples to the bicycle&#39;s rear tire, to provide a resistance force. The rear wheel is typically attached to the frame by fitting the ends of its axles (or its “skewers”) into two opposing members (which are attached to two upward-extending frame arms and which can be shaped as open cylinders or cones). Typically, one member is relatively fixed while the other member is mounted on a shaft that can be adjusted inward. 
     To mount the bicycle in the trainer, the cyclist holds one skewer of the rear wheel in the relatively fixed member, while continuously rotating by screwing (or otherwise continuously translating, e.g., by a cam and follower) the adjustable shaft inward, until snug. The widths of various bicycle tire axles typically differ over a range of about 2 inches. Since one end of the bicycle wheel axle remains relatively fixed, a trainer of this type hence varies where the center of the bicycle tire lies with respect to the center of the frame members, when the other axle is secured in place. 
     SUMMARY 
     In general, in one aspect, the invention features an apparatus having: an axle attachment for removably holding an axle wherein the axle attachment is removably engageable with the end of the axle; a threaded shaft coupled to the axle attachment; and a latch that selectively engages the threads of the shaft. 
     Embodiments of the inventions may include the following features. The axle can be of a bicycle wheel. The latch can further include a nut portion, the nut portion selectably engages the threads of the shaft. The nut portion can include female threads which selectably engage the threads of the shaft. A housing can be placed around the shaft, coupled to the latch, and a portion of the latch can be moved towards and away from the housing. The axle attachment and shaft can be urged towards the axle, when the latch is disengaged from the shaft. A crank can be attached to the shaft to rotate the shaft around an axis of the shaft. The latch can further include a nut portion, the nut portion selectably engages the threads of the shaft such that the shaft moves relative to the latch along its axis when the crank is turned. 
     In general, in another aspect, the invention features an apparatus for removably holding an axle including an axle attachment, the axle attachment removably attachable to an end of the axle, a shaft coupled to the axle attachment, the shaft having at least one first position holder, and a housing around the shaft, the housing having at least one second position holder, the second position holder selectably mating with the first position holder. 
     Embodiments of the invention may include the following features. The axle can be of a bicycle wheel. The first position holder can be a pin, and the second position holder can be a ledge along an inside surface of the housing. Or, the first position holder can be a ledge along the outer surface of the shaft, and the second position holder can be a pin along an inside surface of the housing. A spring can couple the shaft and the housing, and the spring can releasably hold the first position holder against the second position holder. The shaft can have one first position holder and the housing can have at least two second position holders, or the shaft can have at least two first position holders and the housing can have one second position holder. The shaft can be moved relative to the housing such that the first position holder ceases mating with one of the second position holders in exchange for mating with another of the second position holders. The shaft can be moved relative to the housing such that the second position holder ceases mating with one of the first position holders in exchange for mating with another of the first position holders. 
     Advantages of the invention include the following. A cyclist can quickly and easily center a bicycle wheel within the frame of a bicycle trainer, and then quickly and easily tighten the bicycle axle within the trainer frame. The bicycle wheel can be relatively accurately centered within the frame to a selected degree of precision, by easily adjusting a shaft within a centering mechanism against a number of spaced position holders. The bicycle wheel can be grossly and then finely adjusted into a firm attachment. First, a shaft can be pushed within a rapid attach/release mechanism such that a releasable latch releases the shaft, pushing the shaft&#39;s end towards the wheel. A hand or even a leg can be used to push the shaft in this manner. Once the shaft is roughly in place, the latch can couple to threads on the shaft, allowing for fine adjustment and tightening by turning the shaft against the latch. The bicycle wheel is easily released by pulling the latch away from the shaft (after possibly loosening the shaft one or more turns). The invention allows a cyclist to train on a bicycle that is well-centered upon a stationary trainer, and allows the cyclist to easily attach and then release the bicycle wheel from the trainer. Centering of the bicycle within a trainer can be important for user balance and comfort, as well as for designing compact and sturdy resistance units that can function with many types of bicycles. 
     These and other features and advantages of the present invention will become more apparent from the following description, drawings, and claims. 
    
    
     DRAWINGS 
     FIG. 1 is a view of a bicycle trainer having centering and rapid attach/release mechanisms. 
     FIG. 2 is a rear view of the bicycle trainer with bicycle positioned for use by a rider. 
     FIG. 3 is an exploded view of a rapid attach/release mechanism for the bicycle trainer. 
     FIGS. 4 a  and  4   b  are top and cross-sectional views of the rapid attach/release mechanism. 
     FIG. 5 is a lower perspective view of a latch of the rapid attach/release mechanism. 
     FIGS. 6 a  and  6   b  are upper and cut-away perspective views of an assembled rapid attach/release mechanism. 
     FIGS. 7 a  through  7   c  are cross-sectional views displaying the operation of the rapid attach/release mechanism. 
     FIG. 8 is an exploded view of the centering mechanism. 
     FIGS. 9 a  and  9   b  are top and cross-sectional views of the centering mechanism. 
     FIGS. 10 a  and  10   b  are upper and cut-away perspective views of an assembled centering mechanism. 
     FIGS. 11 a  and  11   b  are perspective cut-away views of a centering bearing of the centering mechanism. 
     FIG. 12 shows the inside of the centering bearing, viewed along its axis. 
     FIGS. 13 a  through  13   d  are cross-sectional views displaying the operation of the centering mechanism. 
     FIGS. 14 a  through  14   d  are cut-away perspective views displaying the operation of the centering mechanism. 
     FIGS. 15 a  and  15   b  are exploded and assembled views of the rapid attach/release and centering mechanisms with bicycle trainer frame. 
     FIG. 16 is a perspective view of an alternative rapid attach/release arrangement. 
     FIG. 17 is a perspective view of an alternative rapid attach/release arrangement. 
     FIG. 18 is a perspective view of an alternative rapid attach/release arrangement. 
    
    
     DESCRIPTION 
     FIGS. 1 and 2 show a bicycle trainer  1  which includes a rapid attach/release mechanism  10  and a centering mechanism  12  coupled to a frame  14 , and a resistance unit  16 . Rear wheel  18  of bicycle  20 , having an axle with protruding skewers  19   a  and  19   b , attaches to centering mechanism  12  and rapid attach/release mechanism  10 , and removably couples to resistance unit  16 , for use by a rider to simulate outdoor rides. One example of a frame and resistance unit combination is shown in U.S. Pat. No. 5,611,759, incorporated herein by reference. 
     Referring to FIGS. 3,  4   a , and  4   b , the rapid attach/release mechanism  10  includes an axle engagement member in the form of a first notched member  22   a , screw shaft  24  and crank shaft  26 , screw housing sleeve  28 , lever-actuated latch  30 , screw housing  32 , latch pin  34 , latch holes  36   a  and  36   b , screw tube  38 , screw bearing  40 , spring  42 , crank  44 , and crank handle  46 . Screw shaft  24  and crank shaft  26  can be either distinct attached components, or fabricated as a unit. 
     First notched member  22   a , screw shaft  24  and crank shaft  26 , and crank  44  with crank handle  46  are attached together to form a member  48 . Spring  42  presses against the inside surface of crank  44  to spring-load against screw bearing  40 . 
     First notched member  22   a  removably couples to a skewer  19  of a bicycle, allowing the bicycle wheel to freely rotate about its axle axis. Screw shaft  24  has threads  25  along a portion of its length, which are exposed, when assembled, through screw window  29  of screw housing sleeve  28 . Threads  25  can be “acme” type. Spring  42  can be placed fully within screw tube  38  and screw bearing  40 , or within another housing, to secure spring  42  from the environment and a user&#39;s fingers. 
     Lever-actuated latch  30  attaches to screw housing  32  via latch pin  34  inserted through latch holes  36   a  and  36   b . Referring also to FIG. 5, latch  30  includes hole  50  (through which latch pin  34  slides to hold latch  30  in place with latch holes  36   a  and  36   b ), and a nut region  52 , which has partial threads  54  fabricated to mate with corresponding threads  25  on screw shaft  24 . Nut region  52  descends through screw window  29  to removably couple to screw shaft  24 . Latch  30  can also include a safety catch to secure latch  30  in its engaged position against screw shaft  24 , thereby preventing unwanted slippage of the bicycle wheel from trainer  1 . Latch  30  can be located on the upper portion of the rapid attach/release mechanism  10  to allow gravity to help keep it in its engaged position. 
     FIGS. 6 a  and  6   b  further show the assembled rapid attach/release mechanism  10  in perspective and cut-away views. FIGS. 7 a  through  7   c  show the operation of rapid attach/release mechanism  10 , allowing easy attachment of a bicycle wheel  18  to frame  14 . In its initial released state of FIG. 7 a , first notched member  22   a  is completely retracted against screw housing  32 , latch  30  is snugly resting upon screw shaft  24 , and spring  42 , pressing against screw bearing  40 , forces crank  44  outward, away from screw housing  32  and screw bearing  40 . 
     As shown in FIG. 7 b , the user need only apply a sufficient force in direction  60  to push crank  44  towards screw housing  32  and screw bearing  40 , compressing spring  42 . This forces the surface of nut region  52  of latch  30  away from the threaded surface of screw shaft  24  so as to lift the end of latch  30  away from screw housing  32 . This force also pushes first notched member  22   a  away from screw housing  32  and towards a skewer of the bicycle wheel  18 . In this manner, a user can quickly achieve a gross positioning of first notched member  22   a  against the bicycle wheel skewer with a simple inward pressing motion that releases latch  30  and allows screw shaft  24  to quickly advance towards the skewer. The user can press against crank  44  either with a hand or with a leg (if the hands are occupied), making operation of rapid attach/release mechanism  10  convenient. Once force is released, latch  30  falls back into place. Then the friction of screw threads  54  on surface  52  of latch  30  against threads  25  of screw shaft  24  holds screw shaft  24  in its grossly-adjusted position. 
     Once first notched member  22   a  has been grossly adjusted in place against the skewer, more fine adjustment is possible. As shown in FIG. 7 c , rapid attach/release mechanism  10  is finely adjusted to tighten against the skewer by turning crank handle  46  around axis  62  of screw and crank shafts  24  and  26 . Latch  30  engages the threaded portion  25  of screw shaft  24 , such that turning crank handles  46  finely adjusts the position of first notched member  22   a , by turning threaded portions  25  of screw shaft  24  against threaded portions  54  of nut portion  52  of latch  30 . The compressive force of spring  42  works in concert with mated threaded portions  25  and  54  to retain first notched member  22   a  in position. 
     The user can easily and quickly release first notched member  22   a , thereby freeing an attached bicycle wheel, by lifting up on latch  30 , possibly after loosening crank  44  one or more turns. Lifting latch  30  removes the connection between threads  54  and  25 , thus allowing shaft  24  to move freely. This allows screw and crank shafts  24  and  26  to be pushed outward by compressed spring  42  to the position shown in FIG. 7 a.    
     Referring to FIGS. 8,  9   a  and  9   b ,  10   a  and  10   b , centering mechanism  12  includes second notched member  22   b , centering shaft  70  attached to inner centering shaft  72  (having protruding centering pin  74 ), centering bearing  76 , spring  78 , washer  80 , e-ring  82 , centering housing  84 , and centering end-cap  86  held in place with screws  88 . 
     When assembled, spring  78  is loaded between washer  80  (held in place by e-ring  82  within notch  73  of inner centering shaft  72 ) and surface  90  of centering bearing  76 . This forces centering assembly  96  (comprising second notched member  22   b , centering shaft  70 , and inner centering shaft  72 ) as far within centering bearing  76  as possible, in direction  94 . Centering pin  74 , forced against a first centering ledge  92   a  within centering bearing  76 , retains assembly  96  against the force exerted by spring  78 . 
     Referring to FIGS. 11 a ,  11   b , and  12 , a number of centering ledges  92   a  through  92   d  are located within, and along the longitudinal axis of, centering bearing  76 . In one embodiment, four ledges  92  are used, each separated from the other by about 0.313 inches along axis  102  of centering bearing  76 , and by about 60° around the axis. Any convenient choice of distances and angular displacements between successive centering ledges  92  can be chosen. Centering ledges  92   a  through  92   d  can be shaped as rounded depressions, into which centering pin  74  fits, and are separated by (along axis  102 ) sloped separation barriers  98   a  through  98   c . Inner centering shaft  72  fits within shaft cavity  100 , such that centering pin  74  will rest upon (or within) any one centering ledge  92  at a time. 
     Referring also to FIGS. 13 a  through  13   d  and  14   a  through  14   d , a user can, by pulling second notched member  22   b  against the force of spring  78 , and twisting assembly  96  around axis  102 , pull centering pin  74  out of one such centering ledge  92  (along axis  102 ), over a respective separation barrier  98 , and into another centering ledge  92 . Since the new centering ledge is located a given distance either forward or backward along axis  102  from the prior centering ledge (all within centering bearing  76 ), this movement results in a forward or backward displacement of assembly  96  relative to centering bearing  76 . Spring  78  retains centering pin  74  against its current centering ledge  92 , until pulled and twisted again by the user. 
     Referring to FIGS. 15 a  and  15   b , rapid attach/release mechanism  10  and centering mechanism  12  are assembled and then attached to a trainer frame  14 . By pulling and twisting assembly  96  of centering mechanism  12 , a user can adjust wheel attachment assembly  11  so that bicycle wheel  18  is located reasonably close to center  104  between end-portions  106   a  and  106   b  of frame  14 . The spacing and number of centering ledges  92  provided in centering mechanism  12  can adjust the resolution for centering bicycle wheel  18  as required (the greater the number of ledges, and the smaller their relative spacing, the greater the centering resolution). Once the user has adjusted centering mechanism  12  for his or her bicycle wheel, rapid attach/release mechanism  10  can be gross adjusted by a quick force against crank  44 , pushing first notched member  22   a  against its respective wheel skewer, and then can be fine adjusted by rotating crank handle  46 , tightening first notched member  22   a  against the skewer. When an indoor training exercise (for example) has been completed, the user can quickly release the bicycle by pulling up on latch  30  (after possibly releasing pressure by unscrewing crank  44  one or more turns), thereby using the spring loaded rapid attach/release mechanism  10  to force first notched member  22   a  away from its respective skewer. 
     Other embodiments are within the scope of the claims. The apparatus and methods can be adapted to reasonably center, hold, and then rapidly release any type of wheel, for any purpose. With respect to the centering mechanism, pin  74  can be an elongated ribbed area, as in FIG.  16 . An open channel  104 , having centering ledges for the pin, can be fabricated completely through a centering bearing  76 ′, as in FIG.  17 . Having the pin extend through channel  104  also allows placing labels directly upon centering bearing  76 ′ to relate each pin position (and thereby centering position) with categories of bicycles, to center corresponding wheel widths (e.g., “mountain”, “racing”, etc.). Further, ledges  106  (or similar channels) can be placed along (and within the surface of) centering shaft  72 , such that a centering pin  74 ″ can be attached to centering bearing  76  instead, essentially reversing their respective locations (as in FIG.  18 ). Any form or shape of ledge can be used. Various other spring arrangements and ledge directions can be used to retain the skewer-holding member at a particular location. 
     With respect to the rapid attach/release mechanism, other latch arrangements can be used, for example, a latch can completely encircle the circumference of the screw shaft, but selectably disengage the latch&#39;s inner threads from the threads of the screw shaft, to allow a quick gross adjustment of position. The latch can be arranged to disengage by pushing downward instead of lifting upward. Various other spring, latch, and thread arrangements and directions can be used to retain the skewer-holding member at a particular location.