Abstract:
The present invention teaches an apparatus and method of use for a highly efficient bicycle skewer. In each of three separate embodiments an insert moves laterally with respect to a captive nut in such a way as to provide the necessary clearance required to remove a wheel or attach a wheel to a bicycle frame. The apparatus is constructed in such a way as to allow the removal and attachment without the need for adjustment of the skewer as is required by the prior art devices and is suitable for both front and rear wheels.

Description:
BRIEF DESCRIPTION 
       [0001]    The subject of this invention relates to the bicycle industry. More specifically, the disclosed invention teaches a novel bicycle axel skewer that once set, maintains the proper gap between the skewer and mounting lugs of a bicycle frame thereby improving the user&#39;s ability to maintain the bicycle. The apparatus of the disclosed invention may be used for driven and non-driven hubs. 
       BACKGROUND OF THE INVENTION 
       [0002]    Chain driven bicycle drive trains have existed for many years. Generally the chain receives power input from a peddle crank that has a motive force exerted upon it from a rider&#39;s legs. The force is transferred by the chain to the driven wheel by a geared cog, for example, which is in turn mechanically linked to a hub. The hub is attached to the drive wheel by means of spokes or solid inserts such as in the so-called disk wheels. In this way linear force from a rider&#39;s legs is transformed to rotational force applied to the wheel and then to the road surface. 
         [0003]    From time to time the wheels of a bicycle must be detached from the bicycle frame, for example, to change a flat tire or to replace a worn part. There exist many contemporary methods for attaching the a wheel to the bicycle frame. One method uses a solid axle threaded on both ends. Once the axle ends have been located correctly in the frame lugs, nuts are tightened to fix the wheel in place. A second method uses a hollow axle through which a rod, referred to in the art as a skewer, is run. One end of the skewer has a lever and the other end an adjustable nut. Once the wheel is in the correct position in the lugs of the bicycle frame the lever is operated which results in a clamping force to fix the wheel in place. 
         [0004]    While these methods are functional, they suffer from a common flaw. In both cases the rider must perform multiple steps to remove the wheel for the bicycle frame. In the first case, a wrench must be used to loosen both nuts, then the nuts run out away from the frame lugs prior to removing the wheel. In the case of the lever operated skewer, once the tension on the skewer rod has been released by operating the lever, the nut on the opposite side from the lever must be loosened in order to clear the frame lugs to allow removal of the wheel. 
         [0005]    Once the wheel is clear, maintenance can occur. But the same problems exist upon remounting of the wheel. For the case of the solid axel, the wheel must be inserted into the frame lugs, then each of the nuts run in to fix the wheel in place, then a wrench must be applied to both nuts to firmly secure the wheel in place. For the case of the lever operated skewer, the wheel must be located in the frame lugs, then the nut run in to the approximate position required to engage the lever, then the rider must operate the lever to see if the nut is in the correct position. This process must be repeated several times in order to ensure proper capture of the dhub in the bicycle frame. Both of these method require numerous steps and are very inefficient. 
         [0006]    What would be desirable is a method for mounting/dismounting a bicycle wheel that eliminated the need for the user to deal with nuts or inefficient lever mechanisms. The apparatus of the present invention provides an improved wheel mounting/dismounting method that accomplishes this as well as eliminating other problems related to the prior art methods discussed above. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention teaches an apparatus and method of use for a highly efficient bicycle skewer. In each of three separate embodiments an insert moves laterally with respect to a captive nut in such a way as to provide the necessary clearance required to remove a wheel or attach a wheel to a bicycle frame. The apparatus is constructed in such a way as to allow the removal and attachment without the need for adjustment of the skewer as is required by the prior art devices and is suitable for both front and rear wheels. 
         [0008]    Each of the three embodiments of the present invention also has the advantage of keeping all wheel mounting hardware, such as the alignment springs and captive nut, together so that when the wheel is removed no pieces are lost. All embodiments of the present invention are self limiting so that a rider knows positively that the proper lug clearance had been reached. Since the present invention requires only an initial adjustment, once the wheel is ready to be remounted, no trial-and-error need be accomplished to guarantee a precise fit and clamp force on the lugs of the bicycle. 
         [0009]    The three embodiments of the present invention work on the same principle and differ only in the implementation of that principle. Each of the embodiments uses a concentric insert that travels along a thread internal to a captive nut. The initial adjustment involves setting the proper lug clearance, then fixing the relative position of the insert with respect to the captive nut. Once accomplished, the lateral movement needed to provide the proper lug clearance gap is done through operation of a lever and cam mechanism common in the art. 
         [0010]    The first embodiment of the present invention uses a simple shear force differential. The shear force between the external threads of the insert and the internal threads of the captive nut is greater than the shear force between the threads of the skewer rod and the internal threads of the insert. Thus when the skewer rod is rotated the skewer rod/insert combination moves laterally with respect to the captive nut creating a gap sufficient for wheel removal and/or remounting. 
         [0011]    The second embodiment of the present invention uses a set screw method. The shear force between the external threads of the insert and the internal threads of the captive nut are generally the same as the shear force between the threads of the skewer rod and the internal threads of the insert, however, a set screw is used to fix the skewer rod/insert combination once the proper gap has been determined. Thus when the skewer rod is rotated the skewer rod/insert combination moves laterally with respect to the captive nut creating a gap sufficient for wheel removal and/or remounting. 
         [0012]    The third embodiment of the present invention again uses a simple shear force differential. The shear force between the external threads of the insert and the internal threads of the captive nut is greater than the shear force between the threads of the skewer rod and the internal threads of the insert in the same way as in the first embodiment, however in the third embodiment the shear force differential is accomplished through the use of a jam nut on the internal threads of the insert. Thus when the skewer rod is rotated the skewer rod/insert combination moves laterally with respect to the captive nut creating a gap sufficient for wheel removal and/or remounting. As discussed below in conjunction with drawings provided, all three embodiments of the present invention provide a superior solution for riders. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1 : is an exploded/sectioned view of the apparatus of the present invention. 
           [0014]      FIG. 2 : provides details of the apparatus and operation of a first embodiment of the present invention. 
           [0015]      FIG. 3 : provides details of the apparatus and operation of a second embodiment of the present invention. 
           [0016]      FIG. 4 : provides details of the apparatus and operation of a third preferred embodiment of the present invention. 
           [0017]      FIG. 5 : provides the details of the installation and method of use of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0018]    As described briefly above, the apparatus and method of the present invention provides a highly efficient bicycle wheel mounting skewer.  FIG. 1  shows an exploded view of the apparatus of the present invention  100 . A cam housing  10  contains an internal cam (not shown) which is operated by lever  15 . The cam is attached to skewer rod  20  such that when lever  15  is operated the cam causes the skewer rod  20  to move approximately 0.2 inch laterally. Note that since the lever  15 , housing  10  and cam are of the conventional type and well understood in the art, no detailed drawing or description is provided for clarity. 
         [0019]    Spring  30 A and spring  30 B are of the conventional type, but both utilize a unique shouldered capturing means such that when the bicycle wheel is removed from the bicycle frame the springs  30 A and  30 B remain in place. This is an advantage over conventional methods since in these methods the springs are free to move along the skewer rod  20  making it difficult to insert the wheel into the lugs when remounting. Moreover, in conventional methods if the nut is inadvertently removed from the solid axel or the skewer rod the springs are easily lost. In the present invention for both springs, as discussed below in conjunction with  FIGS. 2 ,  3  and  4 , a lip is provided to capture the spring. 
         [0020]    Looking now at captive nut assembly  200  comprised of captive nut  60 , insert  50 , stop ring  40  and spring  30 B, the novelty of the present invention is shown in detail. As discussed below, these three parts combine to provide an elegant and efficient method for setting a precise fixed gap between the frame lugs of a bicycle and the skewer such that each time the lever  15  is operated, the cam housing  10  and the captive nut  60  separate by the exact distance needed to remove the wheel from the frame. Upon remounting, since the gap is fixed and therefore remains unchanged, the wheel will slip into place without the need to adjust the skewer mechanism. 
         [0021]    Turning now to  FIG. 2 , several views of the details of a first embodiment of the present invention are shown. Note that while  FIG. 2 , as well as  FIGS. 3 ,  4 , and  5 , discuss the details of the present invention with respect to a driven, or rear wheel, the apparatus is suitable for both driven and non-driven wheels, thus may be used for both front and rear wheel applications. 
         [0022]    Beginning with  FIG. 2A , an exploded/sectioned view of the captive nut assembly  200  is shown including captive nut  60 , insert  50 , stop ring  40  and spring  30 B. The outer threads of insert  50  mate with the internal threads of captive nut  60  such that the fit is not tight. As explained further below, this is so that when the rider turns the skewer rod  20 , the insert  50  turns with respect to the captive nut  60  while remaining stationary to the insert  50 . Stop ring  40  is of the c-ring type and snaps into slots  64  such that when the skewer rod/insert combination is turned, no lateral movement beyond stop ring  40  is permitted. Alternatively, stop ring  40  can be of the split ring type. Spring  30 B snaps into place over shoulder  62  such that when lateral movement of the skewer rod  20  occurs, the spring  30 B travels with captive nut assembly  200 . In this way, when the wheel is removed from the chain stay lugs the spring remains with the captive nut assembly  200 . 
         [0023]      FIG. 2B  shows the first embodiment of the present invention in the mounted condition. That is, when the wheel is mounted to the frame of the bicycle, insert  50  has traveled as far as possible along the internal threads of captive nut  60 . Spring  30 B has been compressed by the lug of the bicycle chain stay and has thus receded into the cavity of captive nut  60 . While not shown for clarity, it will be understood by those skilled in the art that skewer rod  20  is connected to lever  15  and housing  10  of  FIG. 1  in such a way as to cause the lateral movement of insert  50 . Note that the threads of skewer rod  20  mate with the internal threads of insert  50  with an interference fit. This is done in order to assure that when skewer rod  20  is rotated by lever  15  of  FIG. 1 , the insert will move with respect to captive nut  60  while remaining stationary with respect to insert  50 . 
         [0024]      FIG. 2C  shows the first embodiment of the present invention in the open, or dismounted condition. Here skewer rod  20  has been manipulated via lever  15  and housing  10  of  FIG. 1  in such a way as to cause the insert  50  to move laterally toward stop ring  40 . Once the stop ring  40  has been reached the movement of skewer rod  20  is inhibited and the rider knows that the proper separation gap has been attained and may now remove the wheel from the lugs of the bicycle frame. Spring  30 B has expanded but remains with the captive nut  60  as described above. 
         [0025]    Referring now to  FIG. 3 , several views of the details of a second embodiment of the present invention are shown. Beginning with  FIG. 3A , an exploded/sectioned view of the captive nut  60 , set screw  70 , insert  50 , stop ring  40  and spring  30 B is shown. The outer threads of insert  50  mate with the internal threads of captive nut  60  such that the fit is not tight. As explained further below, this is so that when the rider turns the skewer rod  20 , the insert  50  turns with respect to the captive nut  60  while remaining stationary to the insert  50 . Stop ring  40  snaps into slots  64  such that when the skewer rod/insert combination is turned, no lateral movement beyond stop ring  40  is permitted. 
         [0026]    Spring  30 B snaps into place over lip  62  such that when lateral movement of the skewer rod  20  occurs, the spring  30 B travels with captive nut  60 . In this way, when the wheel is removed from the chain stay lugs the spring remains with the captive nut  60 . 
         [0027]    Hole  66  is provided in the end of captive nut  60  to allow access to set screw  70 . The purpose of set screw  70  is to exert a captive force on the end of skewer rod  20 . This is required since the fit between the threads of skewer rod  20  and the internal threads of insert  50  is no different than the fit between the external threads of insert  50  and the internal threads of captive nut  60 . If no captive force were provided it would not be clear which element of the apparatus would move when the skewer rod  20  is rotated. With the application of the captive force the skewer rod/insert combination remains fixed allowing the insert  50  to move with respect to captive nut  60 . 
         [0028]      FIG. 3B  shows the second embodiment of the present invention in the mounted condition. That is, when the wheel is mounted to the frame of the bicycle, insert  50  has traveled as far as possible along the internal threads of captive nut  60 . Spring  30 B has been compressed by the lug of the bicycle chain stay and has thus receded into the cavity of captive nut  60 . While not shown for clarity, it will be understood by those skilled in the art that skewer rod  20  is connected to lever  15  and housing  10  of  FIG. 1  in such a way as to cause the lateral movement of insert  50 . Note that the threads of skewer rod  20  mate with the internal threads of insert  50  and are held in place by the captive force generated by set screw  70 . This is done in order to assure that when skewer rod  20  is rotated by lever  15  of  FIG. 1 , the insert will move with respect to captive nut  60  while remaining stationary with respect to insert  50 . 
         [0029]      FIG. 3C  shows the second embodiment of the present invention in the open, or dismounted condition. Here skewer rod  20  has been manipulated via lever  15  and housing  10  of  FIG. 1  in such a way as to cause the insert  50  to move laterally toward stop ring  40 . Once the stop ring  40  has been reached the movement of skewer rod  20  is inhibited and the rider knows that the proper separation gap has been attained and may now remove the wheel from the lugs of the bicycle frame. Spring  30 B has expanded but remains with the captive nut  60  as described above. 
         [0030]    Looking now to  FIG. 4 , several views of the details of a third, preferred embodiment of the present invention are shown. Beginning with  FIG. 4A , an exploded/sectioned view of the captive nut  60 , insert  50 , stop ring  40  and spring  30 B is shown. In this third embodiment, the insert  50  is further comprised of outer sleeve  54  and inner barrel  52 . Outer sleeve  54  is made of the same material as captive nut  60 , typically aluminum. Inner barrel  52  is made of a material such as neoprene. Inner barrel  52  is force fit into outer sleeve  54 , together forming insert  50 . 
         [0031]    The outer threads of insert  50  mate with the internal threads of captive nut  60  such that the fit is not tight. As explained further below, this is so that when the rider turns the skewer rod  20 , the insert  50  turns with respect to the captive nut  60  while remaining stationary to the insert  50 . Stop ring  40  snaps into slots  64  such that when the skewer rod/insert combination is turned, no lateral movement beyond stop ring  40  is permitted. Spring  30 B snaps into place over lip  62  such that when lateral movement of the skewer rod  20  occurs, the spring  30 B travels with captive nut  60 . In this way, when the wheel is removed from the chain stay lugs the spring remains with the captive nut  60 . 
         [0032]      FIG. 4B  shows the third, preferred embodiment of the present invention in the mounted condition. That is, when the wheel is mounted to the frame of the bicycle, insert  50  has traveled as far as possible along the internal threads of captive nut  60 . Spring  30 B has been compressed by the lug of the bicycle chain stay and has thus receded into the cavity of captive nut  60 . While not shown for clarity, it will be understood by those skilled in the art that skewer rod  20  is connected to lever  15  and housing  10  of  FIG. 1  in such a way as to cause the lateral movement of insert  50 . Note that the threads of skewer rod  20  mate with the internal threads of insert  50  with an interference fit. Recall from above that the inner barrel  52  is a soft material such as neoprene while the threads of the skewer rod  20  are formed from a hard material, for example, steel. The combination of the inner barrel  52  and outer sleeve  54  form a jam nut. This is done in order to assure that when skewer rod  20  is rotated by lever  15  of  FIG. 1 , the insert will move with respect to captive nut  60  while remaining stationary with respect to insert  50 . 
         [0033]      FIG. 4C  shows the third, preferred embodiment of the present invention in the open, or dismounted condition. Here skewer rod  20  has been manipulated via lever  15  and housing  10  of  FIG. 1  in such a way as to cause the insert  50  to move laterally toward stop ring  40 . Once the stop ring  40  has been reached the movement of skewer rod  20  is inhibited and the rider knows that the proper separation gap has been attained and may now remove the wheel from the lugs of the bicycle frame. Spring  30 B has expanded but remains with the captive nut  60  as described above. 
         [0034]    Operation of the apparatus of the present invention is shown in  FIG. 5 . Beginning with  FIG. 5A , the apparatus is shown in the closed, or wheel mounted condition. Note that while not part of the invention, the chain stay lugs  82 A and  82 B as well as a typical hub assembly  80  are shown for reference. Initial adjustment of the apparatus of the present invention is accomplished in one of two ways. For the first and third embodiments, the wheel is placed in the lugs  82 A and  82 B of the bicycle frame with lever  15  in the up, or closed position. Recall that lever  15  operates a cam internal to housing  10  in a way that moves skewer rod  20  laterally. 
         [0035]    Captive nut  60  is rotated until it is snug against the driven side frame lug  82 B. Doing this accomplishes two actions: first, insert  50  travels until it abuts the inside of captive nut  60 , and second, continuing to turn captive nut  60  causes insert  50  to reach its final position on rod  20 . Since the skewer rod/insert combination in both the first and third embodiments depends on a shear force differential, when the skewer rod  20  is turned, only the insert will move with respect to the captive nut. 
         [0036]    At this point the lever  15  is moved to the open position as indicated by arrow A. The rider then turns the captive nut approximately one quarter of a turn further. This quarter turn provides the correct clamping force against the lugs. Moving the lever  15  to closed position now applies the clamping force. At this time the skewer of the present invention is properly set and no further adjustment will be needed. 
         [0037]    For the second embodiment of the present invention initial adjustment is accomplished in slightly different manner. This is because the set screw ( 70  of  FIG. 3A ) is used to provide the captive force needed to maintain the proper fixed relationship between the skewer rod  20  and the insert  50 . As with the first and third embodiments, captive nut  60  is rotated until it is snug against the driven side frame lug  82 B. Doing this accomplishes two actions: first, insert  50  travels until it abuts the inside of captive nut  60 , and second, continuing to turn captive nut  60  causes insert  50  to reach its final position on skewer rod  20 . 
         [0038]    At this point the lever  15  is moved to the open position as indicated by arrow A. The rider then turns the captive nut approximately one quarter of a turn further. This quarter turn provides the correct clamping force against the lugs. The set screw  70  of  FIG. 3A , accessed through hole  66  of  FIG. 3A , is tightened against the end of skewer rod  20  to apply the captive force needed to ensure that the relative position of skewer rod  20  and insert  50  remains constant. Moving the lever  15  to closed position now applies the clamping force. At this time the skewer of the present invention is properly set and no further adjustment will be needed. 
         [0039]    Turning now to  FIG. 5B , to remove the wheel from the bicycle the rider moves the lever  15  to the open position, approximately  180  degrees as indicated by arrow B. This action removes the clamping force and allows the rider to turn lever  15  counterclockwise until insert  50  hits stop ring  40  of  FIG. 2C . When the insert  50  has reached stop ring  40  of  FIG. 2C  the gaps X 1  and X 2  are formed. These gaps are approximately even due to the action of springs  30 A and  30 B, each being approximately 0.1 inch. Gap X 1  between housing  10  and chain stay lug  82 A in combination with gap X 2  between captive nut  60  and chain stay lug  82 B provide the approximately 0.2 inch required to clear the safety tabs on the end of the majority of modern bicycles. 
         [0040]    With lever  15  in the open position the rider is able to remove the wheel from the bicycle frame. Once the rider has accomplished the maintenance of the wheel, for example, changing a flat tire, the wheel may be replaced. Since the relative position of the insert  50  and captive nut  60  has not changed, the gaps X 1  and X 2  remain adequate for mounting the wheel without any adjustment to the skewer. Once the wheel is in place on the chain stay lugs  82 A and  82 B the lever  15  is turned clockwise until the insert  50  stops against the captive nut  60 . Again, since the relative position of the insert  50  and captive nut  60  has not changed, the rider simply moves the lever  15  into the closed position which applies the proper clamping force without the need for any trial-and-error adjustment of the skewer. In this way the present invention significantly improves the efficiency of the skewer. 
         [0041]    One advantage of the present invention is a significant improvement in the operation of the skewer. Once properly adjusted, the rider need only operate the skewer lever to remove or remount a bicycle wheel. 
         [0042]    A second advantage of the present invention is the elimination of the need for a trial-and-error method to obtain proper clamping force on the chain stay lugs. Since the relative position of the various components of the present invention remain constant, no further adjustment is required. 
         [0043]    A third advantage of the present invention is that it may be used for both front and rear wheels. The clearance provided by the operation of the apparatus provides the required gaps to allow either type of wheel to clear the safety tabs that are present on most modern bicycles.