Patent Abstract:
Apparatus for controlling a hydraulic circuit to be used for operating hydraulic clutches with a pump ( 8 ) connected with a relevant reservoir ( 88 ) for the fluid of the hydraulic circuit and comprising a piston ( 89 ) sliding within a relevant chamber ( 80 ) provided with one or more ports ( 83, 84 ) for connection to said reservoir ( 88 ), the said piston being so shaped as to close/open the said ports ( 83, 84 ) upon its stroke along said chamber ( 80 ), apparatus being characterized in that the idle stroke of the piston ( 89 ) within said chamber ( 80 ) is adjustable through a rotation of the same piston ( 89 ) about its longitudinal axis.

Full Description:
[0001]     The present invention relates to an apparatus for controlling a hydraulic circuit for a clutch of motor vehicles, especially of motorcycles and the like.  
       BACKGROUND OF THE INVENTION  
       [0002]     It is known that the action to be exerted on the pack of the clutch diks is made easier by means of a hydraulic circuit which comprises a pump and a piston acting on the disks&#39; pack. In the motorcycles, for example, a lever is provided for operating said pump whose activation determines the displacement of the piston.  
         [0003]     In the motorcycles provided with a traditional apparatus of this type, a drawback is due to the relative difficulty of adjusting the idle stroke of the control lever. In fact, in the existing devices, the lever is connected to a piston sliding into a respective chamber exhibited by the pump and, in order to adjust the idle stroke of the lever it is currently necessary to move axially the piston with respect to the chamber inside which it slides. This approach is however very complex structurally, and affects negatively the constructional simplicity of the device and its robustness upon use, besides raising the relevant production cost thereof.  
       SUMMARY OF INVENTION  
       [0004]     The main object of the present invention is to provide an easily adjustable apparatus for controlling hydraulic circuits.  
         [0005]     This result has been achieved, according to the invention, by adopting the idea of making an apparatus having the characteristics disclosed in the claim  1 .  
         [0006]     Further characteristics being set forth in the dependent claims.  
         [0007]     Among the advantages of the present invention there is the fact that it is possible to adjust the idle stroke for the operation of the clutch&#39;s hydraulic circuit with greatest ease; that the controlled circuit maintains its original characteristics; that no protruding parts are provided likely to be damaged or be a danger for the driver of the vehicle being equipped with the apparatus; that the apparatus has extremely limited overall dimensions and, therefore, gives the handlebar a greater compactness; that a more attractive appearance is conferred to the handlebar; that the apparatus keeps its characteristics unchanged also after a prolonged service life. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     These and other advantages and characteristics of the invention will be best understood by anyone skilled in the art from a reading of the following description in conjunction with the attached drawings given as a practical exemplification of the invention, but not to be considered in a limitative sense, wherein:  
         [0009]      FIG. 1  shows a view in longitudinal section of a possible exemplary embodiment of an apparatus for controlling hydraulic circuits according to the invention, in association with a portion of the handlebar;  
         [0010]      FIG. 2  is an enlarged detail of the embodiment of  FIG. 1 , in which some lines in the drawing have been omitted for the sake of simplicity;  
         [0011]      FIG. 3  is a perspective view from below of the apparatus of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]     With reference to the example shown in the attached figures, an apparatus  1  according to the present invention can be associated with a portion of a motorcycle or the like, such as a handlebar, for example, by means of suitable fixing means (not shown). The present apparatus comprises a body  3  (shown only partially) inside which a cavity  88  is formed defining the reservoir for the fluid of the hydraulic circuit. The said reservoir  88  results positioned between the handlebar, to which the body  3  is fixed, and a lever for operating the pump acting on the hydraulic circuit of the clutch. The clutch-operating lever (not shown) results linked with a connecting rod  86  having spherical head, as represented on the left side of the attached figures.  
         [0013]     Shown in  FIG. 1  is a conduit  7  making part of the hydraulic circuit and connecting the apparatus  1  to the piston  77  which acts upon the clutch disks, the latter being schematically represented by the block  70  in  FIG. 1 .  
         [0014]     The conduit  7  is connected downstream of a pump  8  in correspondence of an outlet port  87  through which the fluid of the hydraulic circuit is pushed when acting on the clutch&#39;s control. The pump  8  is defined by a chamber  80  included in the body  3  and inside which a piston  89  slides. The piston  89  is connected to the control lever via the connecting rod  86  which is disposed, relative to the piston, on the side opposite to the position of port  87  in the chamber  80 . The actuation of the control lever is cause for the displacement of the piston  89  (from left to right when referring to arrow F of  FIG. 1 ) towards the port  87 . The return of piston  89  to its rest position is determined by a spring  82  whose reaction is in a direction opposite to that indicated by arrow F in  FIG. 1 .  
         [0015]     As best shown in  FIG. 2 , keeping the piston  89  within the chamber  80  is ensured by the presence of a bush  10  provided with a relevant gasket  11 .  
         [0016]     The bush  10  is solid to the piston  89  and, for this reason, the piston  89  can rotate together with the bush  10  relative to chamber  80 . Solid to the bush  10 , that is, made as one body therewith, is a knob  16  disposed radially with respect to the longitudinal development of the chamber  80 , that is, substantially orthogonal to the longitudinal axis X-X of the chamber  80 . The rotation of the knob  16  determines a corresponding rotation of the piston  89  within the chamber  80 .  
         [0017]     The chamber  80  is connected with a reservoir  88  via two ports  83  and  84  which are disposed in a region acted upon by the piston&#39;s slide. In a manner known per se, the fluid is made to pass bidirectionally through the ports  83  and  84  between the reservoir and the chamber  80  during the axial displacement of the piston  89 , that is, during the actuation of the pump  8 .  
         [0018]     Fitted on the piston  89  is a gasket  9  having circumferential development. The gasket  9 , along its circumferential profile, exhibits a different extension in axial direction. In practice, the gasket  9  has a longitudinal development with a height varying therealong. Indicated by D 9  in  FIG. 2  is the difference between the height of the overlying edge  99  and the corresponding extent of the underlying edge  98 . In other words, the plane of said edges  98 ,  99  forms an acute angle, that is, an angle lower than 90°, with the said axis X-X.  
         [0019]     This particular shape of gasket  9  is cause for a different interaction of the piston  89  with respect to the ports  83  and  84  of reservoir  88 . In other words, the interaction front of the gasket  9  with the ports  83  and  84  is displaced in the axial direction; in practice, by rotating in one direction or the other the piston  89  (which can be obtained by means of knob  16 ), the gasket  9  closes in advance or with delay the port  83 , that is, before or after the intervention on the clutch. There is thus obtained an adjustment of the idle stroke of the relevant lever through an extremely simple and effective solution.  
         [0020]     Advantageously, moreover, the reservoir  88  is defined by a corresponding cavity formed in the body  3  of the apparatus  1 . In particular, reference being made to  FIG. 3 , the body  3  of the apparatus  1  has a concave, substantially semicylindrical surface  30  and is so shaped as to be complementary with the profile of a tubular element of the handlebar. The reservoir  88  is closed on top by a lid  38 . The lid is provided with screws  5  going therethrough to fix the apparatus  1  to the handlebar  2 . Moreover, the lid  38  is of concave shape so that it can fit complementarily with the profile of the handlebar tube  2 . This characteristic allows the reservoir  88  to be seated stably in a region protected against bumps and tampering with.  
         [0021]     On the body  3 , on either side of said surface  30 , there are provided seats  39  for receiving corresponding screws  5  allowing the attachment of the apparatus  1  to the handlebar. The apparatus  1  also comprises a semicollar  4  having a concavity  40  of substantially semicylindrical shape so as to fit complementarily with the handlebar. Provided on the semicollar  4  are through holes to receive the said screws  5 .  
         [0022]     This undoubtly provides a further advantage in terms of safety inasmuch as no protruding parts are present that could be damaged or cause a danger for the driver of the vehicle. Besides, the apparatus has extremely reduced overall dimensions, thereby confering a greater to the handlebar compactness and a more attractive appearance.  
         [0023]     The construction details may vary in any equivalent way as far as the shape, dimensions, elements disposition, nature of the used materials are concerned, without nevertheless departing from the scope of the adopted solution idea and, thereby, remaining within the limits of the protection granted to the present patent.

Technology Classification (CPC): 5