Patent Abstract:
A rack for carrying a bicycle on a vehicle. The rack includes forward and rear crossbars extending across a top surface of the vehicle and a pair of tower bodies associated with each crossbar to secure the crossbars to the vehicle. A wheel mount is attached to a first one of the crossbars. The wheel mount is adapted to support a wheel of the bicycle with a lowest point on the wheel positioned over a range of positions relative to the crossbar including with the lowest point positioned off the wheel mount.

Full Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a continuation of U.S. patent application Ser. No. 10/196,330 filed Jul. 15, 2002 now U.S. Pat. No. 6,601,712 which application is a divisional application of U.S. patent application Ser. No. 09/910,649 filed Jul. 20, 2001 now U.S. Pat. No. 6,460,708 titled “Bicycle Carrier” which application is a divisional application of U.S. patent application Ser. No. 09/447,908 filed Nov. 23, 1999 now U.S. Pat. No. 6,283,310 titled “Bicycle Carrier” and are hereby incorporated by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to bicycle carriers and more particularly to a fork block and wheel tray used to secure a bicycle on a roof rack. 
   BACKGROUND OF THE INVENTION 
   With the growing popularity of bicycling as a recreational activity, vehicles are often equipped with racks to transport bicycles. Such racks come in many different styles and configurations. One common configuration is a roof rack in which one or more bicycles are mounted to a pair of crossbars that extend across the top of the vehicle. 
   Various systems have been developed to secure and stabilize bicycles on vehicle-mounted cross arms. One such system utilizes a fork block mounted to one of the bars with a skewer extending therethrough to receive and grip the front forks of a bicycle. Typically, a wheel tray extends from the fork block to the other crossbar to receive the rear tire of the bicycle. In a slight variation, a short wheel tray is attached to only one crossbar to receive the rear wheel. One limitation of this variation is that the rear wheel must be substantially centered over the crossbar to avoid creating excess torque on the short wheel tray and/or crossbar. This limitation can be a problem where the crossbars cannot be positioned on the vehicle to accommodate the wheel base of a particular bicycle, or where it is desirable to carry bicycles with different wheel bases. 
   In addition to meeting the basic physical requirements of mounting a bicycle on a vehicle, it is also important for a rack to permit the bicycle to be locked on to prevent unauthorized removal. In systems utilizing fork blocks, this is usually accomplished by providing a lock associated with the skewer to prevent the skewer from being opened. Existing lock designs are either unnecessarily complex or not sufficiently secure. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  is a perspective view of a bicycle roof rack according to the present invention. 
       FIG. 2  is an exploded perspective view of a fork block according to the present invention. 
       FIG. 3  is a sectional view through the fork block of FIG.  2 . 
       FIG. 4  is a perspective view of a lower surface of a cap forming part of the fork block of FIG.  2 . 
       FIG. 5  is a sectional view through the fork block of FIG.  2 . 
       FIG. 6  is a cam follower forming part of the fork block of FIG.  2 . 
       FIG. 7  is a view of a lock portion of the fork block of FIG.  2 . 
       FIG. 8  is a graph of displacement as a function of rotation for various cam profiles. 
       FIG. 9  is an exploded perspective view of a wheel mount according to the present invention. 
       FIG. 10  is a sectional view of the wheel mount of FIG.  9 . 
       FIG. 11  is a perspective view of a clip according to the present invention. 
       FIGS. 12 and 13  illustrate various mounting positions for the wheel mount of  FIG. 9  on a round crossbar. 
       FIGS. 14 and 15  illustrate various mounting positions for the wheel mount of  FIG. 9  on a rectangular crossbar. 
       FIG. 16  is a perspective view of an alternative wheel mount according to the present invention. 
       FIG. 17  is a side-sectional view of the wheel mount of FIG.  16 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A bicycle mounting system according to the present invention is shown generally at  10  in FIG.  1 . System  10  includes a roof-mounted rack  12  that attaches to factory installed tracks  14  on a roof  16  of a vehicle  18 . Rack  12  includes towers  20  that interconnect the tracks to crossbars  22 . A bicycle  24  is secured to the crossbars by a fork block  26  and a wheel mount  28 . 
   The construction of fork block  26  is shown in  FIGS. 2-7 . As shown in  FIG. 2 , fork block  26  includes a molded plastic body  30  with an upper section  32  and a lower section  34 . The facing perimeters of each section are formed with stepped edges  36  that interlock with each other. The two sections are secured together by three bolts  38  that engage three corresponding nuts  40 . The bolts pass through holes  42  molded in each section. A socket  44  is formed at the bottom of each hole on the lower section to receive a nut. See FIG.  3 . The inside end of the socket is hexagonally shaped in cross-section to prevent the nut from rotating once placed in the socket. 
   Each section includes a channel  48  adapted to fit over a crossbar. The channel is shaped, as shown in  FIG. 3 , to allow installation on either round or rectangular bars, which are the two most common shapes. The channels are sized so that as the sections just come together, the channels grip the bar with sufficient pressure to prevent slippage along the length of the bar. A plurality of reinforcing ribs  50  run across the channels and are provided with teeth  52 . The teeth bite into a pliable coating that is typically applied to the surface of round crossbars to stabilize the fork block against rotation about the bars. The teeth are generally unnecessary in the case of rectangular crossbars where the non-symmetric cross-section prevents rotation. 
   The upper section includes wheel tray receiver in the form of a protrusion  58  configured to receive the front end of an elongate wheel tray  60 . A corresponding recess  62  is formed in the lower section. The wheel tray is secured to the protrusion by a screw that fits down through a hole  64  in the protrusion, through a hole  66  in the tray and into a flat nut  68  which rides in a track  70  formed in the bottom of the wheel tray. As will be described below, and as depicted in  FIG. 1 , the fork block can also be used with a short wheel tray rather than tray  60 . 
   A ridge  74  runs across the top of the upper section with a bore  76  formed therethrough to receive a skewer  78 . The ridge is formed with a gap  80  at the center and extensions  82  at each end. Metal bearing sleeves  84  are pressed over the extensions to provide a hard surface for the forks to press against. A security cover or cap  86  fits into a recess  88  formed in the top of the upper section. The cap includes a retainer  90  that fits into the gap in the ridge around the skewer to hold the cap on the upper section. See FIG.  4 . 
   It should be noted that the cap blocks access to the heads of the bolts that secure the upper and lower sections together. As a result, the sections cannot be removed from the crossbar without removing the cap. Since the cap cannot be removed without removing the skewer, as long as the skewer cannot be removed, the fork block and bicycle carried thereon cannot be removed from the vehicle. 
   The skewer is part of a skewer assembly  94 , shown in  FIGS. 2 and 5 , that also includes a cam lever  96 , a cam follower  98  and an adjustment nut  100 . The skewer includes a flattened section  102  with a hole  104  near the end to receive a pivot pin  106  which pivotally connects the cam lever to the skewer. The cam lever includes a slot  108  that fits over the flattened section and allows the cam lever to rotate thereon. The pin is preferably press fit through a hole  110  formed in the sides of the cam lever on either side of the slot and through the skewer. 
   The cam lever includes a handle portion  112  to allow a user to pivot the lever. As the lever pivots, a cam surface  114  that rides against the cam follower. The cam surface is shaped so that as the cam lever is pivoted, it pushes the cam follower toward the fork block. More particularly, the cam surface is shaped so that, as the lever is rotated from the open position to the closed, the cam follower is moved rapidly over the first two-thirds of rotation and then slower and with greater leverage as the closed position is approached. The shape of this profile is depicted at  115  in FIG.  8 . The adjustment nut is positioned on the skewer to adjust as necessary for different fork thickness. 
   The described cam surface profile provides rapid throw with low force during the first part of closing where the forks have not been contacted and high force at the end to clamp the forks. As a result, it is not necessary to loosen the nut to allow the forks to be removed, even when the forks are equipped with knobs to prevent accidental wheel loss. This is in contrast to the standard eccentric circle cams utilized on prior skewers. An eccentric circle has a throw rate as a function of rotation that starts small, reaches a maximum rate of change at 90-degrees, and decreases again until the closed position is reached. See the curve indicated at  116  in FIG.  8 . It can be seen that curve  115  has the same slope, and therefore clamping force as a function of rotation during the final section of operation, but has a much higher slope where no pressure is required. With an offset circular cam, the overall throw cannot be increased without increasing the slope in the clamping region and thus decreasing the available clamping leverage. By way of comparison, the skewer clamp of the present invention provides more than three-eighths of an inch of throw versus the five-sixteenths or less typically found in circular cam devices. This increased throw comes without a corresponding reduction in holding force because of the shape of the cam surface. Although the size of a circular cam can be increased to achieve a desired throw, the resultant device would have less clamping force for a given torque on the cam than the system of the present invention. This reduced force may prevent adequate grip on the bicycle forks or may make the force required to close the cam unacceptably high. 
   The cam follower has an elongate hollow cylindrical body  118  that fits over the skewer. The body includes a serrated end  120  disposed toward the fork block to improve the grip on the bicycle fork. See  FIG. 6. A  spring  122  is disposed inside the cylindrical body to bias the cam follower against the cam lever. A smooth cam bearing plate  124  is formed on the opposite end of the plate for the cam surface to slide against. The bearing plate includes a lateral extension  126  with a slot  128  formed therein. The flattened end of the skewer passes through a correspondingly-shaped hole  130  in the bearing plate to prevent the follower from rotating on the skewer. 
   The cam lever further includes a lock-receiving bore  132  that is configured to receive a lock cylinder  134 . The lock cylinder snaps into the lock-receiving bore and includes a T-shaped catch  136  that projects out of the cam lever to selectively engage slot  128  in the cam follower. In particular, with the catch oriented parallel to the slot, the cam lever can be moved freely between the open and closed positions. The open position is depicted by the dashed lines in FIG.  5 . However, if the catch is rotated 90-degrees in the slot, as shown by the dashed lines in  FIG. 7 , the lever can no longer be rotated to release the skewer assembly. A key  138  is inserted into the lock cylinder to rotate the catch. 
   As depicted in FIG.  1  and described above, the rear tire can be held to the crossbar by a long wheel tray or wheel mount  28 . Wheel mount  28  is shown in detail in  FIGS. 9-10  and includes a wheel tray portion  140 . The wheel tray portion is cupped along the elongate axis to support a standard sized wheel at two circumferentially spaced points around the perimeter of the wheel. This arrangement eliminates the problem of the wheel tray “rocking” on a single tangent point on the surface of the wheel, as occurs with straight wheel trays. 
   The wheel tray portion is also cupped in the direction transverse to the elongate axis to stabilize the wheel against lateral movement. The wheel is held in the tray portion by a ratchet strap  142 . Ratchet strap  142  is molded as a single piece and includes a central bridge portion  144 , two toothed regions  146  and grip holes  148  at each end. The ends of the ratchet strap are inserted through receivers  150  formed on each side of the wheel tray portion. A spring-biased pawl  152  is associated with each receiver and includes a circular pad  154  to allow a user to pivot the pawl. Teeth  156  formed on the pawl allow the strap to be inserted, but prevent withdrawal unless the pawl is pivoted to disengage the teeth by pressing on the circular pad. When the ends of the strap are inserted and pulled tight, the bridge portion pushes down on the bicycle wheel to hold it against the wheel tray portion. 
   The wheel tray portion is held to a round crossbar by a clip  160 , such as shown in FIG.  11 . Clip  160  includes a recess  162  sized and shaped to closely fit over a round crossbar. A split  164  allows the ends of the clip to be spread apart to install the clip on the crossbar. The top surface  166  of the clip fits against a flat mounting surface  168  formed on the bottom of the wheel tray portion. A bolt  170  fits down through the wheel tray portion and the clip and is engaged by a T-nut  172 . As the T-nut is tightened, the split is pressed together and the crossbar is firmly gripped. 
   As shown in  FIGS. 12 and 13 , the wheel tray portion can be mounted to the crossbar with either the bolt in front or behind the bar. Furthermore, the mount can be rotated around the bar. The ability to rotate around the bar and position the mount slightly in front of or behind the crossbar allows the mount to accommodate bicycles with wide range of wheel bases. The longitudinal cupping of the wheel tray portion around the perimeter of the tire reduces the tendency of the wheel tray to rock on the perimeter of the wheel. This combination of rotational flexibility and stability on the tire transfers torque created when the center of the wheel is placed significantly in front of or behind the cross-arm to the frame of the bicycle instead of causing the mount to rotate around the crossbar. 
   The mount can also be used with a rectangular cross-section crossbar by utilizing a rectangular clip  176 , as shown in FIG.  9 . Clip  176  is constructed similarly to clip  160 , but includes a recess that is rectangular in cross-section rather than circular. Clip  176  includes a flat side  178  and a stepped side  180 . The flat side is mounted to the wheel tray portion as previously described for the round clip and can be mounted in front of or behind the crossbar to accommodate variations in wheel base. See  FIGS. 14 and 15 . However, because of the irregular cross-sectional profile, it is not possible to rotate the clip around the bar. 
   In order to provide increased range of wheel base accommodation on a rectangular bar, an angled mounting surface  182  is formed on the bottom of the wheel tray portion. The angled mounting surface inclines the wheel tray portion relative to the cross-arm. This simulates in a discrete fashion the effect of rotation in the case of a round bar. As before, the mount can be attached to the crossbar with the wheel tray facing forward or backward. 
     FIGS. 16 and 17  depict a wheel mount  186  having a monolithic construction. Mount  186  includes a wheel tray portion  188  with a construction similar to wheel tray portion  140 . The bicycle wheel is secured in the wheel tray portion by an elastic band  190  with a plurality of holes  192  that is stretched between mounting studs  194  formed on each side of the wheel tray portion. The mount is secured to the bar by a clip  196  formed integrally with the bottom of the wheel tray portion. A slot  198  is formed at one side of the clip to allow it to open up to be installed over a crossbar. A bolt  200  and T-nut  202  are used to tighten the clip on the bar. It should be noted that the cross section of the opening in the clip is sculpted to allow it to be installed on either a round bar or a rectangular bar. In addition, the sculpting allows the mount to be positioned on the rectangular bar at a number of different rotational positions. 
   The above-described arrangements for attaching the mount to the crossbar allows the mount to accommodate wheel base variations of plus or minus 9 inches on round bars and plus or minus 6 inches on square bars. Thus, a bicycle with a wheel base of 32 inches could be mounted together with a bicycle with a 50 inch wheel base on a rack with crossbars spaced at 41 inches. Alternatively, this arrangement allows the position of the crossbars to be adjusted over a wide range of positions when mounting a bicycle of a fixed wheel base. For instance, an average mountain bike has a wheel base of 40-42 inches and can be mounted on bars spaced from 32 to 50 inches. This flexibility allows the rack to be used on a wide range of vehicle styles. With prior systems, the mounting flexibility of the short wheel mount was not possible without using a long-style wheel tray. 
   While the invention has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. Applicants regard the subject matter of the invention to include all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. No single feature, function, element or property of the disclosed embodiments is essential to all embodiments of the invention. The following claims define certain combinations and subcombinations which are regarded as novel and non-obvious. Other combinations and subcombinations of features, functions, elements and/or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such claims, whether they are different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of applicants&#39; invention.

Technology Classification (CPC): 8