Abstract:
A surrogate top tube for use in attaching bicycle without top tubes to vehicle-mounted carriers. The top tube includes yokes at each end for selective attachment to the seat tube and a vertical portion of the handlebars. The top tube may includes structure to prevent the yokes from rotating relative to each other about an axis extending therebetween. The yokes may also include a safety retainer to prevent the yoke from accidentally opening.

Description:
FIELD OF THE INVENTION 
     The present invention relates to bicycle carriers and more particularly to a surrogate top tube used to facilitate mounting of bicycles to a vehicle-mounted carrier. 
     BACKGROUND OF THE INVENTION 
     Bicycles are often transported between locations on mounts that attach to vehicles. In many cases, these mounts incorporate an arm or cradle that the top tube of a bicycle rests on or in to support the bicycle. However, women&#39;s bicycles and many newer, non-traditional frames do not have a top tube. As a result, these types of bicycles cannot be directly mounted on many carriers. 
     In order to overcome the above difficulty, several different surrogate top tube designs have been developed. These devices have a yoke structure at each end of a telescoping tube. The yokes typically attach to the seat tube and the vertical tube of the handlebars. Unfortunately, existing designs suffer from a number of drawbacks. Some systems are relatively difficult to secure and include separate pieces that may easily be misplaced. Other systems, while easy to attach, do not provide a robust connection to the bicycle. Some designs are configured in a way that allow a user to incorrectly install them on a bicycle, such as between a seat tube and the horizontal members on the handlebars, rather than to the vertical member. As a result of mis-installation, this latter device may fail during use, allowing the bicycle to fall from the rack. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a surrogate top tube according to the present invention attached to a bicycle carrier. 
     FIG. 2 is an exploded isometric view of the surrogate top tube of FIG.  1 . 
     FIG. 3 is an exploded isometric view of an anti-rotation structure. 
    
    
     DETAILED DESCRIPTION 
     A surrogate top tube according to the present invention is shown generally at  10  in FIG.  1 . Tube  10  is shown mounted in a carrier  12  adapted to mount to a hitch  14 . The carrier includes arms  16  that support cradles  18 . The top tube is secured in cradles  18  by straps  20 , just as the top tube of a bicycle would normally be gripped. A bicycle  22  is shown in dashed lines held by tube  10 . Tube  10  includes bicycle-gripping mechanisms  24 ,  26  disposed at each end. The gripping mechanisms are described in more detail below and are adapted to selectively receive and secure a vertical tube member of the bicycle, such as seat tube  28  and handlebar tube  30 . 
     As shown in FIG. 2, tube  10  includes an elongate support structure  40  formed by sections  42 ,  44  of metal tubing. Section  42  is sized to fit telescopically into section  44  to allow the length of the support structure to be adjusted to accommodate different size bicycles. An anti-rotation structure  46  that prevents the sections from rotating relative to each other is shown in FIG.  3 . The anti-rotation structure basically consists of a groove  48  formed in the otherwise circular wall of section  42  that interfits with a corresponding depression  50  formed at the end of section  44 . 
     A plastic plug  52  with a serrated flange  54  and a recess  56  is press fit into the end of section  42 . The outer surfaces of the serrated flange are slightly larger than the outside diameter of section  42  and form a contact portion to ride against the internal surface of section  44 . The recess accommodates the groove formed along the length of section  42 . Once the sections are assembled together, a plastic collar  58  is slipped over section  42  and press fit onto the end of section  44 . Collar  58  includes a shallow lip  60  that projects slightly inside the inside diameter of section  44  and engages the serrations on plug  52  to prevent the sections from separating after assembly. 
     By insuring that the gripping mechanisms or yokes remain in the same plane, the anti-rotation structure prevents the user from installing one end of the tube on a vertically oriented seat tube and the other end on a horizontally oriented portion of the handlebar. This latter configuration creates a substantial lateral load on the yokes for which they were not designed and may lead to failure. 
     The yokes disposed at each end of the elongate support structure are very similar in construction, with the exception that mechanism  26  is slightly narrower to accommodate the seat tube as opposed to the handlebar shaft. Therefore, the following discussion will be made with reference to mechanism or yoke  24 . Yoke  24  includes a hook member  70  and a gate member  72 . The hook member is fixed relative to section  44  and the gate is pivotally mounted thereto. The end of section  44  includes two cross-holes  74 ,  76 . A bolt  78  fits through hole  74  and through corresponding holes formed in the end of the hook and the gate. 
     The hook member is riveted to one side of hole  76  to prevent it from pivoting on bolt  78 . The gate is free to pivot on bolt  78 , but is selectively secured in the closed position by a spring-biased button  80 . The spring-biased button is mounted in an end plug  82  that is slipped into the end of section  44 . The button projects out of hole  76  on the gate side and fits into a corresponding hole  84  formed in the gate. The button prevents the gate from pivoting unless the button is depressed. 
     The free end of the gate is stabilized against bending outward by a safety retainer  90  formed on the adjacent free end of the hook. The retainer prevents the outer end of the gate from being bent outward by shifting and rocking of the bicycle or incorrect installation of the top tube. The structural portions of the hook and the gate are formed by a band of metal that is bent into the desired shaped. Plastic or other resilient material is overmolded or coated onto the bands to protect the surface of the bicycle. The overmolding on the hooks is shaped with a depression  94  to help center the secured portion of the bicycle in the hook. By centering the load in the hook, the torque creating a tendency to rotate the tube under load is minimized or eliminated. This reduces the chance that the tube will rotate so that the yokes are vertically oriented, placing a lateral rather than downward load on them. 
     It is believed that the disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions 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. The subject matter of the inventions includes 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 every one of the disclosed inventions. Similarly, where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. 
     It is believed that the following claims particularly point out certain combinations and subcombinations that are directed to some of the disclosed inventions and are novel and non-obvious. Inventions embodied in 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 amended or new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure.