Abstract:
A dual clamp bicycle stem face plate assembly for use in combination with a bicycle steering system includes a dual clamp face plate member attachable to the outside end of the extension arm of a bicycle steering assembly and which further includes an auxiliary or second clamp for retaining and gripping a second handle bar or pair of handles.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This is a utility application based on Ser. No. 60/478,473 entitled “Dual Clamp Bicycle Stem Face Plate” filed Jun. 12, 2003 which is incorporated herewith by reference and for which priority is claimed. 

   BACKGROUND OF THE INVENTION 
   In a principal aspect, the present invention relates to an assembly used in combination with the steering system of a bicycle which enables utilization of at least two handle bars for the steering system. 
   Biking enthusiasts seek to incorporate into their bicycles the most recent technology which will enable them to enjoy their bicycle for recreational as well as sporting purposes. Among the features which biking enthusiasts may employ or desire are handle bar constructions which facilitate steering of the bicycle comfortably and efficiently. Often bicyclists find that a certain handle bar construction is beneficial with respect to certain terrain conditions whereas an alternative handle bar construction is desirable in alternative situations. Alternative weather, environmental or terrain situations may thus require alternative handle bar arrangements when using the bike in order to improve comfort, avoid fatigue or to improve streamlining in the event of sport biking. 
   Thus, there has developed a need for a means to incorporate alternative handle bar assemblies or handle bars in sporting bikes, racing bikes and the like. The present invention is directed to such an objective and further to the objective of enabling biking enthusiasts to incorporate multiple handle bar constructions on a single bicycle in a simplified and efficient manner while avoiding the addition of significant weight and avoiding other encumbrances to the use of the bicycle. Of course, the technology may apply to bicycles having two or more wheels. 
   SUMMARY OF THE INVENTION 
   Briefly, the present invention comprises a dual clamp bicycle stem face plate assembly for use in combination with a bicycle steering system. Typically, a bicycle steering system includes a generally vertical steering tube associated with the front wheel of the bicycle and mounted so as to rotate about its axis in a manner which will enable directional movement of the front wheel. The top of the steering tube typically includes a steering arm extension which may be manipulated by turning handle bars attached to the steering arm extension. The steering arm extension in combination with the handle bars thus provides a mechanical advantage which enables operation of the steering tube by rotation thereof in a highly efficient manner. 
   The invention contemplates a steering arm extension which includes a dual clamp bicycle stem face plate assembly attached thereto. The face plate assembly incorporates a bracket extension which attaches to the steering arm extension and which, in combination therewith, enables attachment of a first set of handle bars. The bracket extension further includes an outer end or a secondary clamp section which in combination with a fastening element enables the attachment of a second handle bar or handle bars. In a preferred embodiment, the first and second handle bars are arranged so that they include parallel crossbar elements retained in alignment by the face plate assembly of the invention. The separate handle bar constructions may thus include unique arrangements of the handles to enable the user of the bike to engage in alternative positions for gripping and holding and steering the bicycle. 
   Various alternative arrangements of the face plate assembly are disclosed, each one being directed to the means for attaching the first and second handle bars to the steering arm extension associated with the steering tube of the bicycle. The handle bars, of course, may be single bar constructions or two part handle bar constructions. For example, the second handle bar may comprise a right hand and a left hand handle and cross bar elements. The invention contemplates a stem face plate assembly which will accommodate such a construction. 
   Therefore, it is an object of the invention to provide an improved stem face plate assembly for use in combination with a bicycle steering system to enable incorporation of at least two sets of handle bars for use with the steering system. 
   It is a further object of the invention to provide mechanically straight forward, yet highly efficient face plate assembly that can be adopted to attach first and second handle bars to the steering mechanism of a bicycle. 
   Yet another object of the invention is to provide a face plate assembly for use in combination with a bicycle which can be utilized in combination with preexisting steering assemblies for bicycles without significant modification or altering of the steering assembly. 
   Another object of the invention is to provide a mechanically efficient, highly reliable and reasonably priced stem face plate assembly for incorporation of two handle bar units in combination with a steering assembly for a bicycle. 
   These and other objects, advantages and features of the invention will be set forth in the detailed description which follows. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     In the detailed description which follows, reference will be made to the drawings comprised of the following figures: 
       FIG. 1  is an exploded isometric view of a first embodiment of the invention; 
       FIG. 2  is a top plan view of the embodiment of  FIG. 1 ; 
       FIG. 3  is a side view of an element of the assembly associated with the embodiment of  FIG. 2 ; 
       FIG. 4  is a top plan view of the element depicted in  FIG. 3 ; 
       FIG. 5  is a top plan view of the element depicted in  FIG. 3 ; 
       FIG. 6  illustrates an alternative construction of the invention; 
       FIG. 7  is a side elevation of another alternative embodiment of the invention 
       FIG. 8  is an isometric view of an additional or other alternative embodiment of the invention; and 
       FIG. 9  is a side view of a traditional prior art bicycle stem assembly. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the figures and in particular  FIGS. 1–5 , there is illustrated a first embodiment of the invention. The invention is incorporated in a bicycle wherein the front wheel of the bicycle  10  may be turned in response to a rotation of a journaled steering tube  12  about its axis of rotation  14 . Rotation of the steering tube  12  in an appropriate bearing housing or housing (not shown) may be effected by manipulating an arm extension or stem extension  16 . The stem extension  16  includes an outside or distal end  18  to which a primary or first handle bar  20  may be affixed. As depicted in prior art  FIG. 9 , extension  16  may have attached thereto a handle bar  20  by means of a primary clamp  21  attached by fasteners  23  to the outer end  18  of the extension  16  having a first arcuate recess  19  in  FIG. 1 . The handle bar  20  may then be pivoted or rotated about an axis  25  and retained in a desired rotational position by tightening of the fasteners  23  so as to engage the clamp  21  tightly against the handle bar  20 . 
   The present invention contemplates removal of the plate or primary clamp  21  of  FIG. 9  and replacement thereof with a specially constructed clamp face plate member  26 . In the embodiment of  FIGS. 1–5  the clamp face plate member  26  includes an arcuate recess  28  for fitting against a first handle bar  20 . Oppositely projecting arms or tabs  30  and  32  are designed to cooperate with fasteners  34  and  36  so as to enable attachment of the claim face plate member  26  to the outside end  18  of the stem extension or arm extension  16 , to thereby retain, between the arcuate face  28  and an arcuate face  19  of the arm extension  16  a first handle bar  20 . It is to be noted that the first handle bar  20  includes a center element or cross bar element  38  which is generally transverse to the stem extension or arm extension  16 . The cross bar element  38  defines an axis of rotation  25  when assembled. 
   In the embodiment of  FIGS. 1–5  the clamp face plate member  26  further includes first and second spaced and generally parallel bracket extension arms  40  and  42  comprising a secondary clamp section which are spaced from one another and connected together by a primary clamp section or plate member  44 . Each of the bracket extension arms  40  and  42  define a generally circular aperture or opening  46  adapted to receive a secondary or second handle bar  50  such as depicted in  FIG. 2  and a third handle bar  52 , respectively, again as depicted in  FIG. 2 . The clamp face plate members  40  and  42  include a fastening element which in the embodiment of  FIGS. 1–5  comprises a bolt fastener  60  and  62 , respectively, which tighten the opposite opposed jaws  64  and  66  of the clamp face plate members  40 ,  42  so as to retain the second or third handle bars  50  and  52 . Note that each of the second and third handle bars  50  and  52  include a cross bar element  51  and  53 , respectively, which define an axis  61  and  63 , respectively. The axes  61  and  63  are coincident axes and are generally parallel to the axis  25  associated with the first cross bar element  38 ; namely, axis  25 . The clamp face plate members  40  and  42  may be constructed so as to provide for offset of the axes  61  and  63 . The axes  61 ,  62  may be offset vertically, horizontally angled with respect to each other, or some combination thereof. Additionally, the utilization of independent clamp face plate members  40  and  42  enables independent adjustment of the second and third handle bars  50  and  52 . Thus, the handle bars  50  and  52  may be rotated independently about their respective axes  61  and  63 . 
   The entire assembly may be attached to the arm extension  16  so that, as depicted in  FIG. 1 , the bicycle steering mechanism will include first, second and third handle bars  20 ,  50 ,  52 . The construction of  FIGS. 1–5  exemplifies the invention in as much as first, second and third handle bars  20 ,  50 ,  52  are attached to a single arm extension  16  with the handle bars  20 ,  50 ,  52  being independently adjustable and one set of handle bars  50 ,  52  being set in front of the other handle bar  20  and not attached one to the other. Various alternative constructions are illustrated by the additional figures. For example, in  FIG. 6  there is illustrated an arm extension  16  with a clamp face plate member  70  attached to the end  18  of the arm extension  16  by means of fasteners  71  and  73 . The clamp face plate member  70  includes or defines a secondary clamp which enables attachment of a second handle bar to the extension  70 . A single fastener  75  is used to compress a closed arm  76  and  77  of the bracket extension. 
     FIG. 7  illustrates another alternative embodiment wherein a bracket extension  80  cooperates with a separate or separable secondary face plate or fastening element  82  attached by means of fasteners  84  and  85  to engage and hold a second handle bar. 
     FIG. 8  illustrates yet another embodiment wherein the clamp face plate member  90  is attached to an arm extension  92 . The clamp face plate member  90  includes spaced or bifurcated sets of arms  94  and  96  which independently grip separate second handle bars  98  and  100 , respectively. 
   While there have been set forth preferred embodiments of the invention, it is to be understood that the invention is limited only by the following claims and equivalents thereof.