Abstract:
A hub adapter used to modify a bicycle wheel hub to provide for the mounting of a disc brake rotor and/or for the repositioning of the wheel spoke mount flange to accommodate the additional components of a disc brake system. The hub adapter may be fixed to the host non-disc wheel hub by fastening bolts passing through the original spoke mounting holes or by other fastening means. The hub adapter may provide standard mounting holes for a disc brake rotor to be fixed to the hub adapter with fastening bolts. The hub adapter provides alternate spoke mounting holes on an alternate spoke flange, positioned in such a way so as to provide adequate clearance for disc brake components such as the disc brake caliper assembly, or in such a way as to change the length of the spokes and to modify the wheel stiffness. The hub adapter effectively becomes integral to the host wheel hub and critical to the primary function of the wheel hub, that is transferring load from the frame to the wheel.

Description:
RELATED APPLICATIONS 
   This application claims the benefit of Provisional Patent Application No. 60/346,276, filed Jan. 9, 2002, by Eric Goss and Daryl Musselman, entitled HUB ADAPTER FOR BICYCLE DISC BRAKE. 

   FIELD OF THE INVENTION 
   This invention relates, in general, to wheel hubs and to the mounting of disc brake systems on wheel hubs that were not specifically designed to receive disc brake system components. 
   BACKGROUND OF THE INVENTION 
   Bicycles delivered prior to 1996, especially mountain bikes, were most often equipped with V-brakes or rim-brakes where a cable actuated cantilever system effectively pinched the wheel rim between two rubber brake pads. Bicycles equipped with such brakes were also equipped with non-disc wheel hubs. Alternatively, bicycle disc-brake systems utilize a frame mounted caliper assembly that squeezes brake pads on a dedicated brake rotor, similar to systems used on modern motorcycles and automobiles. By 2002, the majority of high-end mountain bikes were sold with disc brake systems as standard equipment. Bicycles equipped with such disc-brake systems are equipped with disc-ready wheel hubs, designed specifically to accept the mounting of a dedicated brake rotor. Moving into the future, both rim-brake systems and disc-brake systems will continue to share the market and wheel hub manufacturers will continue to satisfy the needs of both competing systems. 
   The primary function of a wheel hub is to transfer the load of the vehicle and operator, the stationary part, to the rotating wheel, the moving part, through a wheel bearing assembly. In the case of bicycles, this load transfer is generally accomplished by a single piece wheel hub to which wheel spokes are attached, and within which wheel bearings are housed. Currently manufacturers generally supply two different types of wheels and/or hubs, one being non-disc wheels or hubs (i.e. wheels/hubs not designed to mount a disc brake rotor) and the other being disc wheels or hubs (i.e. wheels/hubs designed to mount a disc brake rotor). Accordingly there is a need for a means for adapting non-disc wheels and hubs to disc wheels and hubs. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a hub adapter for adapting a non-disc specific wheel hub to securely mount a disc brake rotor, to modify the spoke mounting position so as to provide clearance for other disc brake system components, such as the disc brake caliper assembly, and to modify the performance of the wheel assembly. The hub adapter has a hub mounting face for fastening said hub adapter to said hub, an adapter spoke flange for fastening spokes of said wheel, and a rotor mounting face for fastening said rotor to said hub adapter. 
   The rotor mounting face is located to allow for the proper positioning and function of the disc brake rotor within the disc brake caliper assembly. Furthermore, the rotor mounting face provides fastening points that are used to secure the disc brake rotor. 
   The new spoke mounting flange is located so as to position the wheel spokes in such a way as to eliminate any potential interference between the wheel spokes and a disc brake caliper assembly. Furthermore, this flange may be located in such a way as to modify the performance of the wheel by affecting its stiffness and/or lateral stability. 
   The hub adapter is securely fastened to the host wheel hub in such a way as to become integral to the host wheel hub. In the preferred embodiment, threaded holes in the hub adapter are located in alignment with holes on the spoke flange of the host wheel hub. Threaded fasteners pass through the holes on the spoke flange of the host wheel hub and are threaded into the holes provided in the hub adapter to securely fasten the hub adapter to the host wheel hub. The invention is not specific to any particular brand or model of wheel hub. In addition, the invention can be designed to fasten securely and function correctly in cooperation with many different types of bicycle wheel hubs, and to accommodate many different types of disc brake calipers and components. Furthermore, the invention applies equally to both the front and rear wheels of bicycles as well as wheels of other vehicles, such as wheelchairs, etc. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention itself both as to organization and method of operation, as well as additional objects and advantages thereof, will become readily apparent from the following detailed description when read in connection with the accompanying drawings, wherein: 
       FIG. 1  is a side view of a hub adapter mounted on a standard non-disc bicycle wheel hub; 
       FIG. 2  is an exploded isometric view of the hub adapter and various components in  FIG. 1 ; 
       FIG. 3  is a front plan view of the hub adapter and various components in  FIG. 1 ; 
       FIG. 4  is a cross section view taken through line A—A of  FIG. 3 ; 
       FIG. 5  is a front plan view of the hub adapter in  FIG. 1 ; 
       FIG. 6  is a side view of a hub adapter similar to that illustrated in  FIG. 5 ; 
       FIG. 7  is a rear plan view of a hub adapter similar to that illustrated in  FIG. 5 ; 
       FIG. 8  is a cross-section view taken through line B—B of  FIG. 5 ; 
       FIG. 9  is a side view of a hub adapter similar to that shown in  FIG. 1 , but for a front wheel hub. 
       FIG. 10  is a cross-section view taken through line C—C of FIG.  9  and illustrating the flange offset typical of a front wheel hub application. 
       FIGS. 11   a  and  11   b  are of a cross section view similar to  FIG. 10 , but with a schematic representation of the disc brake caliper assembly and wheel and spoke assemblies added. 
       FIG. 12  is a side view of an alternate embodiment, where the hub adapter is specifically designed to be integral to a convertible wheel hub. 
       FIG. 13  is a cross-section view taken through line D—D of FIG.  12  and illustrating the alternate embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Shown in  FIG. 1  is a hub adapter  10  of the present invention. The hub adapter  10  is shown fastened to a non-disc specific bicycle wheel hub  12  (i.e. the bicycle wheel hub  12  is not specifically designed to accept a disc brake rotor). The disc brake rotor  14  is shown fastened to the hub adapter  10  by threaded rotor fasteners  16 . The hub adapter  10  is shown fastened to the bicycle wheel hub  12  by threaded hub fasteners  18 . 
     FIG. 2  is an exploded isometric view of the various components shown in FIG.  1 . The bicycle wheel hub  12  is inserted into the large center hole  50  of the hub adapter  10  so as to allow the spoke flange  28  on the bicycle wheel hub  12  to sit flush against the hub mounting face (not shown) of the hub adapter  10  and to be integrally secured by threaded hub fasteners  18 . The threaded hub fasteners  18  are shown to pass through the spoke holes  20  on the bicycle wheel hub  12  and into the threaded holes  34  on the hub adapter  10 . It can be appreciated that the spoke holes  20  are not available to receive wheel spokes when the bicycle wheel hub  12  and the hub adapter  10  are fastened together. New spoke holes  22  are provided on hub spoke flange  30  of the hub adapter  10  to allow wheel spokes to be installed. 
     FIG. 2  further shows the threaded rotor fasteners  16  passing through existing holes  23  on the disc brake rotor  14  and into the threaded receiving holes  24  provided in the rotor mounting face of the rotor mounting flange  27 . The disc brake rotor  14  then sits flush against the rotor mounting face  26  of the rotor mounting flange  27 . 
     FIG. 3  is a front plan view of the various components shown in  FIGS. 1 and 2 . The disc brake rotor  14  is shown fastened to the hub adapter  10  by six threaded rotor fasteners  16  located according to a recognized international industry standard. It can be appreciated that although this international industry standard fastener position is preferred, alternative fastener positions and/or quantity could be conceived that would not depart from the invention. Also, the overall size of the brake rotor  14  may vary without affecting the principle of the invention. 
     FIG. 4  is a cross section view of the various components shown in  FIGS. 1 ,  2  and  3 , taken through line A—A of FIG.  3 . The bicycle wheel hub  12  is shown in schematic cross-section, with no internal components shown. The spoke flange  28  on the bicycle wheel hub  12  sits flush against the hub mounting face  32  of the hub adapter  10  and the bicycle wheel hub  12  and hub adapter  10  are secured by threaded hub fasteners  18 . 
     FIG. 5  is a front plan view of the hub adapter  10 . The disc brake rotor mounting face  26  of the rotor mounting flange  27  and the threaded receiving holes  24  for fastening the disc brake rotor are visible. Behind the rotor mounting flange  27  are the spoke holes  22  and threaded holes  34  for receiving the spokes and threaded hub fasteners, respectively (spokes and threaded hub fasteners not shown). 
     FIG. 6  is a side view of the hub adapter  10 , similar to that shown in FIG.  5 .  FIG. 6  shows that the disc brake rotor mounting face  26  is flat to allow for proper installation of the disc brake rotor, (not shown) whereas the surface of adapter spoke flange  30  may be tapered to allow wheel spokes passing through the spoke holes  22  to be mounted in the correct position and with minimal strain. 
     FIG. 7  is a rear plan view of the hub adapter  10 .  FIG. 7  shows the hub mounting face  32  on the hub adapter  10  to which the spoke flange  28  ( FIG. 4 ) mounts. Threaded holes  34  are shown to which the threaded hub fasteners  18  (see  FIG. 1 ) are secured. The spacing and pitch circle diameter of the threaded holes  34  match the location of the spoke holes  20  of the bicycle wheel hub  12  (see FIGS.  1  and  2 ). While eight threaded holes  34  are shown, any number of holes to a maximum equal to the number of spoke holes  20  ( FIG. 2 ) may be conceived.  FIG. 7  further shows that the new spoke holes  22  provided on the hub adapter  10  are located at the same angular spacing, but on a larger pitch circle diameter than the spoke holes  20  on the bicycle wheel hub  12 , (see  FIGS. 1 and 2 ) which coincide with the positions of the threaded receiving holes  34 . 
     FIG. 8  is a cross-section view of the hub adapter  10 , taken through line B—B of FIG.  5 . The hub mounting face  32  on the hub adapter  10  is shown to be tapered in this instance, to match the shape of the mating surface of spoke flange  28  on the host bicycle wheel hub  12  (see  FIGS. 1 and 4 ) so that the hub adapter  10  may be securely fastened by threaded hub fasteners  18  (see  FIGS. 1 and 2 ) to the host bicycle wheel hub  12  (see FIGS.  1  and  2 ). 
     FIG. 9  is a side plan view of an alternate embodiment of the present invention, shown as intended for use on a front wheel of a bicycle. In this version the hub adapter  10 ′ is shown attached to a front bicycle wheel hub  12 ′. In a similar manner to that illustrated in  FIG. 1 , a disc brake rotor  14  is shown fastened to the hub adapter  10 ′ by threaded rotor fasteners  16 . 
     FIG. 10  is a cross-section view taken through line C—C of FIG.  9 . In this embodiment the hub adapter  10 ′ is shown to be similarly fastened to the host bicycle wheel hub  12 ′ by threaded hub fasteners  18 ′ passing through the spoke holes on the existing spoke flange  28 ′. A significant offset is shown between the existing spoke flange  28 ′ of the host bicycle wheel hub  12 ′ and the new spoke flange  30 ′ on the hub adapter  10 ′. This offset is required to reposition the wheel spokes to allow for the clear mounting and operation of additional disc brake system components such as the disc brake caliper. Unlike the embodiments of  FIGS. 1-8 , the embodiment of  FIGS. 9 and 10  does not have a rotor mounting flange. 
     FIGS. 11   a  and  11   b  are of a cross-section view similar to  FIG. 10 , but with a schematic representation of a disc brake caliper assembly and a wheel and spoke assembly added.  FIG. 11   a  shows how the wheel spokes  36  would typically be mounted to a host non-disc bicycle wheel hub  12 ′, (i.e. a hub which is not specifically designed to accept a disc brake rotor).  FIG. 11   b  shows the same host bicycle wheel hub  12 ′ with a hub adapter  10 ′ installed along with other key components of a disc brake system such as the disc brake rotor  14  and the disc brake caliper assembly  38 . The new wheel spokes  40  fastened to the spoke flange  28 ′ of hub adapter  10 ′ are shown to provide adequate clearance for the mounting and operation of the disc brake caliper assembly  38 . The original wheel spokes  36  (shown as ghost lines in  FIG. 11   b ) are shown to interfere with the mounting position of the disc brake caliper assembly  38 . It can also be seen in  FIG. 11   b  that the location of the disc brake rotor mounting face  26  (see  FIGS. 2 ,  5 ,  6  and  8 ) determines the positioning of the disc brake rotor  14  within the disc brake caliper assembly  38 . The location and orientation of the rotor mounting face  26  and fastening points for the disc brake rotor  14  and the relocation of the wheel spoke flange  28 ′ for brake caliper assembly  38  clearance are key elements of the present invention. 
     FIG. 12  is a side view of an alternative embodiment of the invention applicable to wheel hubs comprising two components. In  FIG. 12  the hub adapter  40  is shown fastened to one such component  42 . Although not shown in  FIG. 12 , the original wheel hub (non-disc wheel hub) comprises two hub components  42  fastened together along respective junction faces  60 . With respect to the original non-disc hub (not shown), comprising two components  42  fastened together, the bearing assembly is contained within the non-disc hub in a manner similar to prior art hubs. Similarly, in the adapted disc hub shown in  FIG. 12 , comprising hub adapter  40  fastened to component  42 , the bearing assembly (not shown) is contained within the adapted disc hub. Although in the embodiment of  FIG. 12 , junction face  60  lies at the centerline of the wheel, it is envisioned that the junction face  60  could also be displaced from the centerline. In this embodiment the hub adapter  40  replaces one hub component (not shown) and is fastened to the remaining hub component  42  by engaging the hub mounting face  62  of the adapter  40  with the junction face  60  of the component  42  using fasteners  58  or other means. Alternatively, the hub component  42  and adapter  40  could each be screw threaded such that they could be screwed together. 
   In the embodiment of  FIG. 12  the hub adapter  40  is interchangeable with one of the two hub components  42 , each of which comprises approximately one half of a wheel hub. The hub adapter  40  does not engage the spoke flange of the host wheel hub  42  as in the embodiments of  FIGS. 1 ,  2  and  4 . The principle of the invention is maintained in that the wheel hub (i.e. the host wheel hub component  42  and hub adapter  40 ) is adapted to mount a disc brake rotor  14 , and/or the position of the spokes may be modified to accommodate the brake caliper assembly. 
   As in the previous embodiments discussed herein, the rotor  14  is fastened to the rotor mounting face  26  of the hub adapter  40  by threaded fasteners  16 . 
     FIG. 13  is a cross-section view taken through line D—D of FIG.  12 . The inside details of the host wheel hub  42  and the hub adapter  40  are shown schematically only. The resulting adapted wheel hub is made up of two separate pieces ( 40  and  42  in the configuration shown) fastened together. 
   The advantage of the embodiment of  FIGS. 12 and 13  is that host wheel hub may be manufactured in two identical parts, (each part being identical to host wheel hub component  42 ) either one of which is interchangeable with the hub adapter  40 . In the embodiments described in  FIGS. 1-11 , the hub adapter  10 ,  10 ′ is fastened to an existing standard wheel hub  12 ,  12 ′ whereas in the embodiment of  FIGS. 12 and 13  one wheel hub component  42  is replaced with the hub adapter  40 . It can be foreseen that the embodiment shown in  FIGS. 12 and 13  could be supplied to retailers and consumers as either a non-disc specific wheel hub, (i.e. a wheel hub comprising a first wheel hub component  42  and a mirror of component  42 ), or as a disc specific wheel hub comprising a wheel hub component  42  and a hub adapter  40 , with potential manufacturing cost savings to the manufacturer. 
   Although the in the embodiments of  FIGS. 12 and 13  the host non-disc wheel hub comprises two substantially identical parts, (each part being substantially similar to host wheel hub component  42 ) it would be readily apparent to those skilled in the art that the host non-disc wheel hub could be made of two hub components that differ in size and/or shape. 
   A further embodiment of the present invention is envisioned adaptation of wheels having an integral hub (i.e. the hub, spokes and rim form one piece). In such integral hub wheels, the position of the spokes obviously cannot be altered to accommodate a disc brake assembly and/or disc brake rotor, therefore, the hub adapter could only be used in those instances where there is sufficient clearance for the disc brake assembly and disc rotor. In addition, alternative means for fastening the hub adapter to the hub may be necessary, since such integral hub wheels do not have spoke flanges  28  or holes  20  such as those shown in FIG.  2 . For example the hub adapter may be bonded to the integral hub wheel using structural adhesive, or the hub adapter may comprise two complementary halves that may be fastened together about the hub of the integral hub wheel. 
   Although various embodiments of the present invention have been described in the context of their application to bicycle wheels, this invention is obviously applicable to wheels of other vehicles (e.g. wheelchairs). 
   Accordingly, while this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.