Abstract:
A connecting element, particularly for connecting rear forks, also known as monostays, made of carbon to bicycle frames. The connecting element is constituted by a first insert and a second insert which are mutually detachably associable at a first end by way of mechanical connection element. The first and second inserts are respectively associated, at a second end, advantageously by way of adhesives, with the stem of a carbon monostay, and are associable with, or rigidly coupled to, a tubular extension of the frame.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a connecting element, particularly for connecting carbon monostays to bicycle frames. 
     Carbon front forks and rear monostays are currently increasingly used, in particular for competitive racing bicycles. This choice is due to the need to have bicycle frames which combine high rigidity with great lightness, and this need is effectively met by carbon-based materials. 
     When manufacturing frames, for example made of metallic alloys of steel or aluminum, it is necessary to deal with the problem of interconnecting a carbon element, the rear fork, and a metal element, i.e., the frame or a part thereof. 
     The prior art related to the use of carbon rear forks or monostays provides, as a solution to the described problem, for the use of adhesives betweeen the two parts, which are shaped appropriately so as to be mutually interlocked. 
     The disadvantage of this system is the fact that the connection, once provided, is permanent and the monostay or rear fork can no longer be removed from the frame. 
     In this manner, when necessary, for example for the replacement of one of the two components due to breakage or technical choice, it is not possible to separate the monostay and the frame. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to solve the above problems, eliminating the drawbacks of the cited prior art, by providing an element which allows to use a non-permanent connection system thereby allowing the carbon monostay to be detachably connected to the frame. Within this aim, an important object of the present invention is to provide an element which allows to obtain a connection which adequately withstands the stresses applied during sports practice. 
     Another object is to provide an element which maintains the rigidity and low-weight characteristics of the carbon rear fork or monostay. 
     Another object is to provide an element which is structurally simple and has low manufacturing costs. 
     This aim and these and other objects which will become better apparent hereinafter are achieved by a connecting element, particularly for connecting rear forks, also known as monostays, made of carbon to bicycle frames, characterized in that it comprises a first insert and a second insert which are mutually detachably associable at a first end by way of a mechanical connection means, said first and second inserts being respectively associated, at a second end, advantageously by way of adhesives, with the stem of said carbon monostay, and being associable with, or rigidly coupled to, a tubular extension of said frame. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the invention will become better apparent from the following detailed description of a particular embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a detail of a bicycle frame with a monostay connected by means of the connecting element according to the present invention; 
     FIG. 2 is a first transverse sectional view of the first insert; 
     FIG. 3 is a front view of a first insert; 
     FIG. 4 is a second transverse sectional view of the first insert; 
     FIG. 5 is a side view of the first insert; 
     FIG. 6 is a side view of a second insert; 
     FIG. 7 is a first transverse sectional view of the second insert; 
     FIG. 8 is a second transverse sectional view of the second insert; 
     FIG. 9 is a lateral sectional view of the invention; 
     FIG. 10 is an exploded view of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the figures, the reference numeral  1  designates a bicycle frame, advantageously made of metallic materials, particularly alloys of steel or aluminum. 
     Said frame has, beneath and behind the saddle, toward the hub of a rear wheel, a tubular extension  2  which is internally hollow and is advantageously circular, oval or teardrop-shaped. 
     A monostay, designated by the reference numeral  3  and made of carbon, is to be applied to said frame  1  and has, in an upward region, a stem  4  for connection to a pair of lateral wings for connection to the hub of the wheel. For the removable connection between said stem  4  and said tubular extension  2 , a connecting element, designated by the reference numeral  5  is used, which is constituted by a first insert  6  and a second insert  7  which are advantageously made of metal and have, in a transverse cross-section, a perimetric shape which is similar to the perimetric shape of said tubular extension  2  or another appropriate shape according to requirements. 
     The first insert  6  and second insert  7  are detachably associable with each other at a first end, designated by the reference numerals  8   a  and  8   b  respectively. 
     The first end  8   b  of said second insert  7  has a first axial seat, designated by the reference numeral  9 , which is shaped complementarily to said first end  8   a  of said first insert  6 , for the insertion thereof and its subsequent detachable coupling. 
     A first circular through hole  10  is provided radially with respect to the lateral surface of said first end  8   a  and is suitable for the passage of appropriate means for mechanical connection between said first insert  6  and said second insert  7 . 
     The first end  8   b  also is radially provided with a second hole, designated by the reference numeral  11 , which is coaxial to said first hole  10  but has a smaller diameter than said first hole and is not a through hole. 
     In this manner it is possible to position, inside said first hole  10 , a bolt, designated by the reference numeral  12 , which is composed of a screw  13  and a nut  14 , which interact with a registration pin  15  which is positioned beforehand inside said first end  8   a , at a suitable second seat which is designated by the reference numeral  16  and is formed at the longitudinal central axis. 
     The registration pin  15  is advantageously designed to prevent the rotation of said nut  14  with respect to said screw  13 . 
     The head of said screw  13  is wider than the diameter of said second hole  11 , so that once said first end  8   a  has been inserted in said first seat  9  of said first end  8   b , the activation of the head of said bolt  12  causes an axial movement, in opposite directions, of said screw  13  and said nut  14 . 
     The free ends of said screw  13  and said nut  14  rest and abut against facing and complementarily shaped walls  17  which are internal to said first end  8   b  of said second insert  7 ; this entails the mutual locking of the two components. 
     The first insert  6  and the second insert  7  have, in opposite positions with respect to the respective first ends  8   a  and  8   b , second ends which are respectively designated by the reference numerals  18   a  and  18   b.    
     The second end  18   a  has a larger cross-section than said first end  8   a , which is connected thereto by means of a wing, designated by the reference numeral  19 , which advantageously has the same shape and dimensions as the outer surface of the stem  4  of said monostay  3 . 
     The stem  4  has, in its end part, a third axial seat, designated by the reference numeral  20 , inside which it is possible to insert, advantageously by gluing, said second end  18   a , whose outside diameter is approximately equal to the inside diameter of said third seat. 
     If allowed by the materials, said tubular extension  2  is appropriately rigidly coupled to said second insert  7  by stable connection or by casting during the manufacture of the frame. 
     Use of the connecting element according to the present invention is therefore as follows: with reference to FIG. 1, the reference numeral  1  designates a frame which has a tubular extension  2  which is advantageously rigidly coupled, for example during casting, to a second insert  7 . 
     A first insert  6  is inserted, advantageously with the application of adhesive, in the third seat  20  formed in a monostay  3  of a frame  1 , so that the wing  19  abuts against the edge of said monostay. 
     A registration pin  15  is then placed in the appropriate second seat  16  formed inside the first end  8   a  of said first insert  6 . 
     The registration pin is designed to support a bolt  12  during the insertion thereof in a first hole  10  formed in the first end  8   a  of said first insert  6 . 
     After arranging the first insert  6  so that said first end  8   a  enters a first seat  9  formed in said second insert  7 , one acts through a second hole  11 , formed in said second insert, so as to partially unscrew the screw  13  from the nut  14  of said bolt  12 . 
     This process causes said screw  13  and said nut  14  to press on the respective inside walls  17  of the second insert  7 , with the consequent detachable mutual coupling of the two inserts and therefore of the metal frame and the carbon monostay. 
     It has thus been observed that the invention has achieved the intended aim and objects, a connecting element for detachable connection between a metal bicycle frame and a carbon monostay having been provided. 
     The invention is of course susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept. 
     The materials used, as well as the dimensions that constitute the individual components of the invention, may of course be more pertinent according to specific requirements. 
     The disclosures in Italian Patent Application No. TV99A000131 from which this application claims priority are incorporated herein by reference.