Abstract:
An apparatus and assembly method including a sprocket hub and a locking collar for go kart vehicles and other land vehicles with drive axles is provided. The present invention eliminates the need for two locking collars on either side of the sprocket hub. The invention further provides a lightweight sprocket hub with a hub neck portion adapted to receive a single locking collar. The sprocket hub fits loosely on the drive axle. The fin-like sprocket hub arms and sprocket hub extensions each have sprocket connection holes used to connect the sprocket hub to a drive sprocket. The locking collar engages the sprocket hub neck portion by means of two flanges located on the sprocket hub. As assembled, the sprocket hub and locking collar float and oscillate on the drive axle to compensate for chassis flex and chain bind such that acceleration of said kart vehicle is enhanced.

Description:
PRIORITY 
   This application hereby claims priority to provisional application No. 60/584,177, filed on Jun. 30, 2004. 

   BACKGROUND 
   The present invention relates generally to a collar and sprocket hub apparatus and particularly relates to a single locking collar and sprocket hub apparatus and method for use on the driving axles of land vehicles. The invention can be used on a variety of vehicles, but is designed specifically for use on go kart vehicles or the like. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a sprocket hub and locking collar which is lighter than the prior art sprocket hubs and collar assemblies. 
   Another object of the present invention is to provide a sprocket hub and locking collar that is more durable and stronger than conventional sprocket hubs with locking collars. 
   Yet another object of the present invention is to provide a sprocket hub and locking collar having a float and oscillating design to compensate for chassis flex and chain bind. 
   Yet another object of the present invention is to provide for the need of only one locking collar to further reduce the rotating weight as compared to the prior art two-collar systems. 
   Yet another object of the present invention is to provide a sprocket hub that has an increased life through the float and oscillating design. 
   Yet another object of the present invention is to provide a sprocket hub that increases the wear of the drive chain and the gear sprocket through the float and oscillating design. 
   Yet another object of the present invention is to provide a lightweight sprocket hub that can attach to a gear sprocket. 
   Accordingly, what is provided is a sprocket hub having a hub front face, a hub rear face and a plurality of fin-like hub arms. The fin-like hub arms are attached to the outer perimeter of a neck portion which extends in a direction perpendicular to a longitudinal axis of an inner perimeter of the neck portion, wherein the fin-like hub arms have recesses defined therein. A hub arm extension is attached to each of the fin-like hub arms, wherein each of the hub arm extensions has a small recess defined therein. A circular neck portion extends outwardly from the hub front face. The circular hub neck portion includes a neck top flange and a neck bottom flange both located on the end of the neck portion distal to the hub front face. These two flanges are used for attachment to the locking collar. The locking collar has an outer, middle and inner perimeter, and houses a compression screw hole  36  and compression screw  36   a  for fastening the collar to a bar adapted to situate in a groove on the driving axle, thus locking the collar onto the axle and sprocket hub. Particularly, a flange groove is defined between the middle perimeter lips and the intermediate surface of the locking collar. This flange groove is spaced such that the neck top flange and the neck bottom flange can fit within the flange groove during attachment of the locking collar to the sprocket hub. 
   Also provided is a method of situating a sprocket on a drive axle comprising the steps of sliding a sprocket hub having a bar slot over a drive axle and sliding a locking collar over the drive axle. The locking collar is attached to the drive axle. Next, the sprocket hub is loosely secured to the drive axle and a gear sprocket is attached to the sprocket hub. The next step involves attaching a drive chain to the gear sprocket and allowing the sprocket hub and the locking collar to float and oscillate on the drive axle to compensate for chassis flex and chain bind. The acceleration of the go kart vehicle is enhanced as a result of this configuration. The configuration also increases the life of the sprocket hub, gear sprocket and drive chain. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a front view of the sprocket hub showing the hub neck portion and hub arms of the present invention. 
       FIG. 2  illustrates a rear view of the sprocket hub of the present invention. 
       FIG. 3  illustrates a side view of the sprocket hub of the present invention. 
       FIG. 4  illustrates a top view of the sprocket hub of the present invention. 
       FIG. 5  illustrates a top view of the locking collar of the present invention. 
       FIG. 6  illustrates a rear view of the locking collar of the present invention. 
       FIG. 7  illustrates a front view of the locking collar of the present invention. 
       FIG. 8  illustrates a perspective view of the driving axle and axle groove bar on which the sprocket hub and locking collar are positioned. 
       FIG. 9  illustrates a cut away view of the sprocket hub and locking collar situated on the driving axle in an engaged position. 
       FIG. 10  illustrates a perspective view of the sprocket hub and locking collar, situated on the driving axle in a spaced apart position. 
       FIG. 11  illustrates another perspective view of the sprocket hub and locking collar, situated on the driving axle in a spaced apart position. 
       FIG. 12  illustrates another perspective view of the sprocket hub and locking collar, situated in an engaged position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The invention will now be described in detail in relation to a preferred embodiment and implementation thereof which is exemplary in nature and descriptively specific as disclosed. As is customary, it will be understood that no limitation of the scope of the invention is thereby intended. The invention encompasses such alterations and further modifications in the illustrated apparatus and method, and such further applications of the principles of the invention illustrated herein, as would normally occur to persons skilled in the art to which the invention relates. 
   The present invention can be described generally as a sprocket hub  10  and a locking collar  30  each with an axle opening ( 21  and  53  respectively) for accepting the driving axle  90  of a go kart vehicle or other land vehicle. The sprocket hub  10  further has a bar slot  25  defined on the outer perimeter of the axle opening  21 . The driving axle  90  includes an axle groove  91  defined therein (see  FIGS. 8-12 ). Within the axle groove  91 , an axle groove bar  92  is capable of being placed, such that the bar  92  fits into the bar slot  25  causing the sprocket hub  10  to rotate in unison with the driving axle  90 . The bar  92  fits loosely into the bar slot  25  to enable the float and oscillating device of the present invention. The bar slot  25  can be seen in  FIGS. 1 ,  2 ,  10  and  11 . 
   As illustrated then with reference to  FIGS. 1-12 ,  FIG. 1  shows a front view of the sprocket hub  10  of the present invention. The sprocket hub  10  has three large fin-like hub arms  14  and three smaller, generally triangular hub arm extensions  14 . The hub arm extensions  14  are attached to the fin-like hub arms  14 . The fin-like hub arms  14  have recesses defined therein to reduce the overall weight of the sprocket hub  10 . Also, the hub arm extensions  14  have small recesses defined therein to reduce the overall weight of the sprocket hub  10 . A recess within the scope of this invention is defined herein as a hole or completely hollowed-out portion and not merely an indentation. 
   Each of these fin-like hub arms  14  and hub arm extensions  14  include sprocket connection holes  12  defined therethrough located proximate to the end of the fin-like hub arms  14  and hub arm extensions  14  opposite from the axle opening  21 . The gear sprocket connection holes  12  are used to attach a gear sprocket to the sprocket hub  10  using a bolt, stud or the like. The sprocket is then connected to a drive chain. 
   The hub arms  14  can be of any geometry as long as the sprocket connection holes  12  generally form the perimeter,of a circle, wherein each is a uniform distance away from the outer perimeter of the axle opening  21 . The hub arms  14  optionally can be replaced with a circular disk or other geometrical figure as long as the sprocket hub  10  includes sprocket connection holes  12  defined therethrough, which form generally a perimeter of a circle-like shape and each is a uniform distance away from the outer perimeter of the axle opening  21 . 
   An optional screw hole  22  is defined through the sprocket hub  10  and is positioned proximate to the bar slot  25  in a direction opposite from the axle opening  21 . The screw hole  22  provides a means whereby a stabilizing screw can be inserted through the hub rear face  23 , travel through the width of the sprocket hub  10 , and connect to the collar bore  34  of the locking collar  30 . This optional stabilizing screw provides greater stability to the sprocket hub  10 , the locking collar  30  and the assembly as a whole. If the optional stabilizing screw is included the invention will not provide as much float and oscillation to compensate for chassis flex and chain bind. 
   The sprocket hub  10  includes a hub neck portion  16  which extends outwardly from the hub front face  24  in a direction opposite from the hub rear face  23 . The hub neck portion  16  is generally radial and has an outer perimeter and an inner perimeter as shown in  FIGS. 1 ,  10  and  11 . The bar slot  25  extends the length of the hub neck  16  and therefore interrupts the radial shape of the hub neck portion  16 . The hub neck portion&#39;s inner perimeter defines an axial opening  21 . The diameter of this axial opening  21  is slightly larger than the diameter of the drive axle  90  to allow the sprocket hub  10  to float and oscillate on the drive axle and to compensate for chassis flex and chain bind. 
   The floating and oscillation of the present invention is generally accomplished by the sprocket hub  10  and bar notch  25  having a loose fit with the drive axle  90  and bar  92 . Floating in particular is caused by a loose fit between the sprocket hub  10 , bar notch  25  and locking collar  30  with respect to the drive axle  90  and bar  92 . Oscillation in particular is the horizontal pivotal movement of the sprocket hub  10  about the drive axle  90 . This oscillation is caused by the sprocket hub  10  and bar notch  25  having a loose fit with the drive axle  90  and bar  92 . 
   The hub neck portion  16  further comprises a neck top flange  18  and a neck bottom flange  19  both located on the end of the hub neck portion  16  opposite from the hub front face  24 . Both the neck top flange  18  and the neck bottom flange  19  have an arc distance d 1  in length, where d 1  is equal to approximately 1.00 inches in this example. The outer perimeter  20  of the hub neck portion  16  defines the outer extent of the hub neck portion  16  in a direction parallel to the longitudinal axis of the axle opening  21 . 
   The locking collar  30  is generally a circular member with an outer perimeter  40 , a middle perimeter  33  and an inner perimeter  32 . Extending outwardly from the outer perimeter  40  in a direction perpendicular to the longitudinal axis of the axle opening  53  is a raised portion  41 , which houses the collar bore  34 , the compression screw hole  36  and compression screw  36   a.    
   The collar bore  34  is a threaded hole cut in the locking collar rear face  50  penetrating towards but not through the locking collar front face  51 . To give the sprocket hub  10  a more rigid structure, an optional stabilizing screw can be inserted into the screw hole  22  on the hub rear face  23 , and pass through the width of the sprocket hub  10 , travel along the hub neck portion  16  and thread into the collar bore  34  of the locking collar  30  when assembled. The stabilizing screw and collar bore  34  are both optional. 
   The compression screw hole  36  accepts the compression screw  36   a.  Compression screw  36   a  is used to fasten the locking collar  30  to the bar  92  in order to lock the locking collar  30  to the sprocket hub  10 . 
   The locking collar front face  51  has a bar notch  52  defined on the inner perimeter  32  and extending towards the outer perimeter  40 . The bar notch  52  loosely accepts the axle groove bar  92  during locking collar  30  attachment to the sprocket hub  10 . The middle perimeter  33  cannot be seen when viewing the locking collar  30  from the locking collar front face  51 . 
   As shown in  FIG. 6 , the locking collar rear face  50  exposes the outer perimeter  40 , the middle perimeter  33  and the inner perimeter  32 . The middle perimeter  33  is located between the outer perimeter  40  and the inner perimeter  32  but is proximate to the horizontal plane of the locking collar rear face  50 . 
   The middle perimeter  33  has two curved, elongated middle perimeter lips  39  extending from the middle perimeter  33  inwardly towards the axle opening  53 . The middle perimeter lips  39  extend parallel with the plane of the locking collar rear face  50 . The middle perimeter lips  39  define two female portions  37  around the middle perimeter  33 , each of which have a length of d 2 , which, in this example, d 2  is equal to approximately 1.01 inches. 
   Located between the locking collar rear face  50  and the locking collar front face  51  is an intermediate surface  54 . The intermediate surface  54  is parallel with the plane of the locking collar rear face  50 . There is a flange groove  38  defined between the middle perimeter lips  39  and the intermediate surface  54 . This flange groove  38  is spaced such that the neck top flange  18  and the neck bottom flange  19  can fit within the flange grove  38  during attachment of the locking collar  30  to the sprocket hub  10 , see  FIG. 10 . 
   When attaching the sprocket hub  10  and locking collar  30  to the driving axle  90 , the axle groove bar  92  is first placed into the axle groove  91  of the driving axle  90 , as shown in  FIGS. 8 and 11 . Then the sprocket hub  10  is slid over the driving axle  90  through the axle opening  21 , as shown in  FIGS. 9-12 . The sprocket hub  10  fits loosely over the drive axle  90  in order to allow the sprocket hub  10  to float and oscillate on the drive axle  90  to accommodate for chassis flex and chain bind. This floating and oscillation of the sprocket hub  10  on the drive axle  90  allows for enhanced acceleration of a go kart vehicle. The floating and oscillation of the sprocket hub  10  also helps reduce excessive wear on the hub sprocket hub  10 , the gear sprocket and the drive chain. 
   Another benefit of the float and oscillation design is the alignment compensation when “lead” or “wedge” is set into the rear axle of the go kart vehicle. Lead is when the axle is cocked to allow the rear of the go kart vehicle to travel sideways (fractionally). Wedge is when the axle is cocked to increase the force on either the right or left tire. Both wedge and lead bring the clutch and sprocket hub  10  out of alignment. The float and oscillating design of the sprocket hub  10  helps to compensate for this misalignment. 
   The sprocket hub  10  should be positioned over the axle groove bar  92  so that the bar slot  25  engages the axle groove bar  92 , see  FIG. 9 . The hub neck portion  16  can face either direction when placed upon the driving axle  90 , as long as it can engage the locking collar rear face  50 . The locking collar  30  is then slid onto the axle through axle opening  53 . The locking collar rear face  50  should be facing the sprocket hub front face  24  when both are positioned on the axle. The neck top flange  18  and the neck bottom flange  19  of the hub neck portion  16  should engage the female portions  37  of the locking collar  30  during assembly. 
   Once the locking collar  30  is generally engaged with the sprocket hub  10  via the neck flanges  18  and  19 , the locking collar  30  should be turned in either a clockwise direction or counterclockwise direction until the compression screw hole  36  is aligned above the bar  92 . This rotation is shown-with reference to  FIGS. 10 and 11 , showing the unengaged, unrotated position, and the engaged, rotated position shown in  FIG. 12 . Upon rotation of the locking collar  30 , the top and bottom flange,  18  and  19  respectively, are positioned behind the middle perimeter lips  38 , which causes the locking collar  30  to become attached to the sprocket hub  10 . 
   After this alignment is made, the user should ensure that the axle groove bar  92  is engaged with the bar notch  52 . The compression screw  36 A is then tightened to essentially “lock” the locking collar  30  into place on the sprocket hub  10 . 
   Once the locking collar  30  is fastened to the sprocket hub neck portion  16 , an optional stabilizing screw (not shown) may be inserted through the hub rear face  23  via the screw hole  22  and attached to the locking collar rear face  50  via the collar bore  34 . The step of utilizing this stabilizing screw adds strength and rigidity to the overall sprocket hub  10  and locking collar  30  assembly. This stabilizing screw is optional, however, as the current assembly can function properly without the use of the stabilizing screw. 
   Generally the present invention is used, on a go kart vehicle or other vehicle, as follows. The vehicle motor spins the clutch, the clutch spins the drive chain, and then the drive chain spins the gear sprocket. The gear sprocket is attached to the sprocket hub  10  by means of bolts, studs or the like. The sprocket hub  10  is attached to the driving axle  90  by means of the axle groove bar  92  and to the locking collar  30  via the compression screw  36 A. This attachment causes the gear sprocket and sprocket hub  10  to rotate in unison with the driving axle  90 , which in turn drives the wheels of the vehicle.