Abstract:
A bicycle trailer hitch assembly including first and second complementary hitch bracket members adapted and arranged for attachment to opposites sides of the bicycle frame rear wheel drop out. Each bracket member includes a main body portion con figured on one side for abutting relation with the bicycle rear wheel drop out and on the other side for receiving the trailer tongue tube to provide center pulling of the trailer. The bicycle quick release skewer which holds the rear wheel clamped to the drop out member likewise secures both brackets to the drop out member. Each of the brackets has a fastener arrangement for enabling securing the bracket to the trailer drawbar.

Description:
CLAIM FOR BENEFIT OF EARLIER FILING DATE 
   The present utility application claims the benefit of U.S. Provisional Application No. 60/494,460 filed on 13 Aug. 2003 and entitled “Trailer Hitch Assembly for a Bicycle”. The present utility application has the same inventor, subject matter and title as the aforesaid Provisional Application. 
   BACKGROUND 
   The background of the invention will be discussed in two parts. 
   FIELD OF THE INVENTION 
   This invention relates to accessories for bicycles, and more particularly to a trailer hitch assembly for use with a bicycle trailer for center pull towing of the trailer. 
   DESCRIPTION OF THE RELATED ART 
   Bicycling has become a standard method of physical exercise, as well as a method of transportation. As part of the use of bicycles for families, there has been a trend toward the use of trailers for bicycles, the trailers having such uses as transportation of small children and transportation of cargo. Trailer hitches have been designed for bicycles for towing such trailers. Many of such trailer hitches are configured for attachment to the frame of the bicycle at one side of the bicycle adjacent the axle of the rear wheel. 
   A typical problem associated with bicycle trailer towing involves the variety in bicycle frames. They are not configured alike and they are usually of a different size. Widths at the rear wheel, along with the angle (crotch angle) formed adjacent the rear wheel between the seat stay and the chain stay, may vary. Further, tube dimensions and cross-sectional shapes for the chain and seat stays may vary from one manufacturer to another. Bicycle hitches are normally attached at or adjacent the crotch angle, and thus, due to these variances in widths and angles, a given hitch may fit only a limited number of bicycle frames. 
   One type of trailer hitch is shown and described in U.S. Pat. No. 4,721,320, entitled “Bicycle Trailer Hitch”, issued to Creps et al. on 26 Jan. 1988. The Creps trailer hitch is configured for attachment to one side of the bicycle frame at the crotch portion of the rear part of the frame, that is, at the junction of the seat stay and chain stay members of the frame. As shown in the drawings of the Creps patent, the trailer hitch is attached on the left side of the bicycle frame, and as a consequence right hand turns of the bicycle are impeded with the bicycle trailer attached. Likewise, if the trailer hitch of Creps is designed to be in like fashion attached on the right side of a bicycle frame, left hand turns of the bicycle would be impeded with the trailer so attached. 
   Another type of trailer hitch is shown and described in U.S. Pat. No. 6,050,581 entitled “Bicycle Trailer Hitch Assembly”, issued to Everett on 18 Apr. 2000. This hitch includes two hitch members configured as mirror images of one another, the hitch members being adapted for attachment to opposing sides of the rear of a bicycle frame. The hitch has the disadvantage of being unduly complex and not sufficiently suitable for a variety of bicycle frame configurations. 
   Such hitches as disclosed in Creps and Everett are illustrative of the varied designs whereby attempts have been made to improve and simplify bicycle hitches for pulling trailers. It is thus an aspect of the present invention to provide a new and improved bicycle hitch for pulling a bicycle trailer that is simple, provides needed performance and safety, and is designed for enabling center pulling of a towed trailer. It is another aspect of the invention to provide a bicycle hitch for center pulling of a bicycle trailer that is attached at the bicycle wheel drop out channels and designed to work with a variety of bicycle frame configurations. 
   SUMMARY 
   In accordance with the present invention there is provided a bicycle trailer hitch assembly including first and second hitch members adapted and arranged for attachment to opposite sides of the bicycle frame at the respective rear wheel drop out channels. The hitch members are complementary to each other but are not necessarily mirror images of one another. Each hitch member includes a main body portion configured on one side for abutting relation with the bicycle frame at the rear wheel drop out channel, and on the other side configured for securely connecting to a trailer tongue. The trailer tongue is configured with a generally U-shaped upper portion for respective bracket connection thereby to provide for center pulling of the bicycle trailer. 

   
     DRAWINGS 
       FIG. 1  is an exploded view of the right side bracket of the bicycle trailer hitch assembly embodying features of the present invention. 
       FIG. 2  is a perspective view of the right side bracket of  FIG. 1  showing the bracket assembled at the right side drop out channel of a bicycle frame; 
       FIG. 3  is plan view of the assembled right side bracket illustrated in  FIG. 2 ; 
       FIG. 4  is a plan view of the back side of the right side trailer hitch bracket as assembled in  FIG. 3 ; 
       FIG. 5  is a plan view of the trailer hitch right side bracket of  FIG. 2  as seen from the rear of the bicycle; 
       FIG. 6  is a plan view of the trailer hitch right side bracket assembly of  FIG. 2  as seen from the front of the bicycle, this view of the assembly being opposite the view of the trailer hitch assembly as shown in  FIG. 5 ; 
       FIG. 7  is a top plan view of the bicycle trailer hitch assembly of  FIG. 2 ; 
       FIG. 8  is a bottom plan view of the bicycle trailer hitch assembly of  FIG. 2 ; and 
       FIG. 9  is a plan view of the of the opposing complementary bracket assembly as mounted on the opposite side of the bicycle frame drop out channel from the bracket shown in  FIG. 2 . 
   

   DESCRIPTION 
   Referring to the drawings there is shown a bicycle trailer hitch assembly embodying features of the invention for attachment to the frame of a bicycle at the rear wheel drop out channels of the frame. Neither the bicycle frame nor the bicycle trailer is shown in detail, there being depicted in broken lines only those structural members necessary to an understanding of the invention. The trailer hitch assembly of the invention includes a first, or right side, hitch member attached to the bicycle frame at the right side of the rear wheel drop out channel area and a second, or left side, complementary configured and dimensioned hitch member attached to the bicycle frame at the opposing or left side drop out channel. As attached in such opposing manner, the first and second hitch members, in conjunction with a respective two-arm trailer tongue (one part of which is shown in  FIG. 1  with the reference numeral  32 ), the trailer can then be towed in what is referred to as a “center pull” manner. 
     FIG. 1  shows the first, or right side of hitch assembly, generally, designated  10 , in exploded view and then shown assembled in  FIG. 2 .  FIGS. 3–8  show various other views of the assembly as shown in  FIG. 2 . As will be further discussed,  FIG. 9  is a plan view of the opposing hitch bracket of the trailer hitch assembly mounted on the opposite side of the bicycle frame from the bracket shown in  FIG. 2 . As illustrated in  FIG. 1 , shown in phantom is the bicycle rear wheel drop out member  30  having drop out channel or slot  30   a , the bicycle rear wheel quick release skewer  31 , and the bicycle trailer (not shown) tongue portion or drawbar  32 . The bicycle rear wheel quick release skewer  31 , which holds the rear wheel clamped to the drop out member  30 , also provides the means to clamp hitch assembly  10  to the drop out member  30 . Thus, the hitch assembly  10  is mounted to the bicycle frame in the drop out channel or slot  30   a  in the same manner as the bicycle rear wheel. Skewer  31  extends through drop out area, or slot,  30   a  and into the opposite complementary bracket (as shown in  FIG. 9 ) on the opposite side of the bicycle frame to likewise secure it to its respective drop out member. The trailer tongue portion or drawbar  32  connects the bicycle trailer to the hitch assembly  10  and provides a horizontal pivot when turning. Respective drawbars connect the bicycle to the trailer from both sides of the bicycle frame to a single center point at the front of the trailer. 
   As best seen in  FIGS. 1 and 2 , hitch assembly  10  includes a main body receiver bracket  20 , tongue bolt  21 , safety lynch pin member  22 , skewer nut  23 , flat washer  24 , inner tongue bolt nut  25 , and outer tongue bolt nut  26 . The bracket  20  on the inside thereof has a generally planar bearing surface for mounting against the right side rear wheel drop out member  30  and when so mounted is secured thereto by quick release skewer  31 . On the other side of bracket  20  there is provided attachment and locking means for the trailer tongue portion  32 . The tongue bolt  21  with threaded end fits into slot  20   c  of bracket  20  and through aperture  32   a  of tongue portion  32  and is locked in place by inner tongue bolt nut  25  and outer tongue bolt nut  26 . Tongue bolt  21  provides the connection between the tongue  32  and the bracket  20  and is held in place by safety lynch pin member  22 . Lynch pin member  22  includes a longitudinal pin for fitting through apertures  20   a  of bracket  20  to secure tongue bolt  21  in slot  20   c  of bracket  20 . Lynch pin member  22  is configured with an enlarged head through which a pull ring is inserted, the enlarged head abutting bracket  20  to provide a stop when the longitudinal pin is inserted through apertures  20   a  and the pull ring providing means for removing the longitudinal pin from apertures  20   a.    
   In configuration, bracket  20  has a generally planar inner bearing surface for mounting against the rear wheel drop out member  30  with the opposite or outer surface facing outward from the bicycle frame. As illustrated in  FIG. 1 , bracket  20  has a generally U-shaped rearward portion as defined by slot  20   c , slot  20   c  having a rearward projecting ear on each side thereof, the ears having complementary apertures for receiving downwardly inserted lynch pin  22 . As indicated in  FIGS. 1–4  the lower ear of bracket  20  is shown of decreased width from that of the upper ear to provide clearance, if needed, for the bicycle gear changing mechanism. The bracket  20 ′ of  FIG. 9  need not, and isn&#39;t shown with, this decreased width. The generally U-shaped rearward portion includes a generally planar surface portion, opposite to and generally parallel with the inner bearing surface, and a forward portion configured with a recess having an aperture  20   b  for receiving skewer  31 , washer  24  and skewer locking nut  23 . 
   Rear wheel quick release skewer  31  is standard to the bicycle and extends through the drop out channel, or slot,  30   a  of drop out member  30  serving to clamp the rear wheel of the bicycle to drop out member  30 . Used in conjunction with flat washer  24 , skewer nut  23  replaces the standard end knob of skewer  31  to thereby utilize more of the threads of skewer  31  to provide a more suitable connection. Inner tongue bolt nut  25  threads onto tongue bolt  21  and then in conjunction with outer tongue bolt  26  is tightened against the tongue  32  to provide a secure assembly. For negotiation of uneven terrain, the hitch assembly  10  works in conjunction with anti-pivot peg  70 , which is variously shown in the drawings. Anti-pivot peg  70  is mounted in drop out channel  30   a  to hold bracket  20  in position to prevent up or down rotation. 
     FIG. 3  is the right side view of the bracket  20  of the trailer hitch assembly  10  as shown in  FIG. 2 , with  FIG. 4  showing the rear or opposite side of bracket  20  from that of  FIG. 3 . Skewer  31  is shown in cross-section indicating its extension into the complementary bracket  20 ′ ( FIG. 9 ) mounted on the left or opposite side of the bicycle frame. 
     FIG. 5  is a view of the trailer hitch assembly bracket  20  of  FIG. 2  as seen from the rear of the bicycle. Shown in phantom is drop out member  30 , trailer tongue drawbar  32  and skewer  31 .  FIG. 6  is a view of the trailer hitch assembly of  FIG. 5  turned 180 degrees, that is, a view as seen looking toward the rear of the bicycle. 
     FIG. 7  is a top plan view of the bicycle trailer hitch assembly of  FIG. 2  and  FIG. 8  is a bottom plan view of the trailer hitch assembled bracket of  FIG. 2 . 
     FIG. 9  is a plan view of the opposing hitch bracket, designated  20 ′, of the trailer hitch assembly located on the opposite side of the bicycle frame from the bracket  20  shown in  FIG. 2 . In this  FIG. 9  part numerals are shown with a prime (′) to indicate the complementary bracket  20 ′, otherwise, except for bracket  20 ′ they are the same as part numerals shown in  FIG. 2  without a prime (′). Hitch bracket  20 ′ may be the mirror image of bracket  20  or may be modified as discussed above in accordance with the invention. In any event, each hitch bracket includes a main body portion having a generally planar bearing surface configured on one side for abutting relation with its respective drop out member, and on the other or opposite side configured for securely receiving its respective trailer tongue member thereby to provide for center pulling of the bicycle trailer. 
   In accordance with the invention, there has been shown and described a new and improved bicycle hitch of compact and efficient construction with provision for pulling a trailer that is simple, provides needed performance and safety, and is designed for enabling center pulling of a towed trailer. While the description has utilized directional references, such as inner, outer, up, upper, under, down, right, left, clockwise, etc., it is to be understood that these terms are utilized with reference to the orientations in the Figures and are not intended to be limiting. While there has been shown and described a trailer hitch for a bicycle embodying features of the invention, other adaptations and modifications may be made without departing from the spirit and scope of the invention.