Adjustment device for motorcycle master cylinders

An adjustable lever assembly for a motorcycle master cylinder includes a first element pivotally connected to the master cylinder, and a manually operable second element pivotally connected to the first element. An adjuster rotatably mounted on the second element can be turned to adjust the angular rest position between the first and second elements.

FIELD OF THE INVENTION

The present invention relates to an adjustment device for a lever device for vehicle control, in particular a lever device for motorcycles wherein the lever rest position is adjustable.

BACKGROUND OF THE INVENTION

In motorcycles, brake and clutch are manually actuated by a pump (“master cylinder”) actuated by a lever device mounted on the handlebar of the motorcycle itself, from which a hydraulic pipe extends to the system to be controlled, for example a brake.

The lever of the lever device is usually arranged along the handlebar grip and the motorcyclist, in order to actuate the lever itself, grips the handlebar along with the lever and closes his/her hand tight so as to turn the lever towards the grip itself. The lever movement produces a thrust that acts on a hydraulic piston, whose stroke or position determines the fluid pressure in said hydraulic pipe to control the brake or the clutch.

Since the various handlebars of motorcycles exhibit different shapes and also the motorcyclists' hands do not all have the same size, the need of being able to adjust the lever rest position relative to the handlebar grip is felt.

Several solutions for carrying out an adjustment of the lever position have been proposed. A group of these solutions provides for an adjustment device of the lever position, such as in U.S. Pat. No. 4,840,082.

This known device is provided with a lever that can rotate about a support shaft for pushing a stem that influences a piston for putting the brake fluid under pressure during the braking action.

The stem selectively couples with at least one seat of different depth of a rotating adjustment block, for varying the operating lever position relative to the handlebar.

Moreover, the lever can be rotated about a coupling shaft against the strength of a spring (“double fulcrum”), for releasing the stem from one of the seats and thus allowing the rotation of the rotating adjustment block by a gripping portion or knob obtained at an end of the rotating block and that raises transversally from the operating lever, or by a screwdriver that acts on a screw at the end of the block itself.

The stem thus slides on guiding grooves, until it couples with the desired seat; in this way, the relative position between lever and handlebar is adjusted.

However, this known device exhibits excessive overall dimensions in the cross direction relative to the adjustment lever, that is, axial to the rotating adjustment block.

SUMMARY OF THE INVENTION

The object of the present invention therefore is to provide an adjustment device for motorcycle master cylinders having such features as to obviate the disadvantages mentioned with reference to the prior art and wherein its assembly and maintenance should be facilitated.

This an other objects are achieved by an adjustment device for motorcycle master cylinders as described below.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, and with reference to the annexed figures, reference numeral1indicates an adjustment device of lever devices for controlling a cylinder-piston unit for vehicles, in particular for adjusting a lever device for motorcycles wherein the lever rest position is adjustable, associable by tightening portions3to a handlebar35of a motorcycle. There are provided means for connecting device1to handlebar35, for example comprising tightening portions3provided with special holes4optionally threaded for seating tightening screws (FIG. 3).

According to the present invention, said device1comprises first operating means2, such as a thrust lever2, turnably associable to the cylinder-piston unit so as to impart an actuation movement to said cylinder-piston unit.

The thrust lever2is therefore associated to the cylinder-piston unit, for example in a cylindrical seat5which slidingly houses a piston.

Moreover device1comprises second operating means7, or gripping lever7, turnably connected to the thrust lever2and suitable for imparting, by a portion thereof, a thrust on said thrust lever2, which causes the transmission of the actuation movement to said cylinder-piston unit, along an angular actuation stroke A (FIG. 5).

The gripping lever7is made turnable relative to the thrust lever2by pivoting on a pin18, as illustrated hereinafter in detail.

The thrust lever2is in turn made turnable by pivoting on a pin, arranged along an axis of rotation X (FIG. 8,9).

The gripping lever7preferably comprises a gripping portion for manually operating on the lever itself (FIG. 5).

In particular, therefore, the adjustment device1is suitable for adjusting the angular position, that is, the distance between the gripping lever7, for example the brake lever and handlebar35, that is, the grip of handlebar35, at will so as to adapt to the driving conditions desired by a user.

Preferably, the thrust lever2comprises a transmission portion8, carrying an eyebolt19, which imparts the actuation movement, by a push rod arranged between the thrust lever2and the piston, to the cylinder-piston unit, for actuating the cylinder-piston unit itself (FIGS. 3 and 5).

The transmission portion8and eyebolt19preferably protrude from the thrust lever2and are arranged on the same plane as the thrust lever2(FIGS. 1,2and3).

According to a preferred embodiment, in fact, eyebolt19is a seat or “glass” shaped recess and exhibits a bottom14which, in the standard use, abuts against the push rod, for actuating the piston.

Thus, when the gripping lever7is placed in rotation along the angular actuation stroke A, it imposes the rotation in the same direction to the thrust lever2too, and consequently the transmission portion8pushes with bottom14of eyebolt19against push rod; in this way, movement is imparted from the gripping lever7, along the angular actuation stroke A, to the thrust lever2and hence to the cylinder-piston unit, in particular to the piston.

In accordance with the present invention, device1comprises adjustment means9arranged between said thrust lever2and said gripping lever7, for adjusting the relative position between said thrust lever2and gripping lever7, that is, for adjusting the distance between said gripping lever7and the grip of handlebar35of the motorcycle.

The adjustment means9are arranged between the gripping lever7and the thrust lever2and are turnably connected to an end of the gripping lever7by a first pin10, as explained in detail hereinafter.

In accordance with the present invention, the adjustment means9carry coupling means13or coupling seats13and operating portions26.

Moreover, according to the present invention, each coupling means13is arranged between or comprised between, two corresponding operating portions26.

In fact, the coupling means13substantially are grooves, or depressions, or coupling seats defined by the operating portions26.

The operating portions26comprise thrust surfaces accessible by an operator and/or a user of the motorcycle, for allowing a rotation of the adjustment means9about the first pin10.

In fact, in accordance with the present invention, the adjustment means9are provided with a rotation hole11, suitable for housing the first pin10.

Moreover, said thrust lever2comprises coupling counter-means29, suitable for coupling with said coupling means13, for cooperating with the coupling means13themselves, and allowing the desired adjusted position to be kept.

In fact, the coupling means13selectively couple with the coupling counter-means29, for defining at least one angular rest position R of said gripping lever7relative to handlebar35, that is, between the thrust lever2and the gripping lever7(FIG. 5).

By rest position R it is meant a position of the gripping lever7wherein the coupling counter-means29couple with said coupling means13, but the transmission portion8does not substantially impart a pressure on the brake fluid through the piston.

In other words, the gripping lever7can be operated along the angular actuation stroke A, which extends from the angular rest position R of the gripping lever in a first direction of rotation.

In fact, along the angular actuation stroke A, the thrust lever2and the gripping lever7are integrally coupled, that is, along the angular actuation stroke A they cover in their movement the same angular width, thanks to the fact that the coupling counter-means29are constantly in abutment in a desired coupling seat13of the adjustment means9.

Moreover, the gripping lever7can also be turned along an angular adjustment stroke C which extends from said angular rest position R in a second direction of rotation, opposed to the first direction of rotation (FIG. 5); during the angular adjustment stroke C, the adjustment means9are uncoupled from the coupling counter-means29and an “open” adjustment position P of the gripping lever7is reached, opposed to the rest position R, along the angular adjustment stroke C.

When the adjustment means9are uncoupled from the coupling counter-means29, that is, for example, in the adjustment position P of the gripping lever7, it is possible to rotate the adjustment means9themselves for adjusting the position of the gripping lever7, as illustrated hereinafter in the description.

Thus, in other words, the rest position R is an “interface” position, that is, an intermediate or neutral position, between the angular actuation stroke A and the angular adjustment stroke C, wherein the gripping lever7is held in abutment by special elastic means20,120on the thrust lever2and at the same time, the coupling means13are coupled with the coupling counter-means29.

In yet other words, in the rest position R no thrust is imparted on the cylinder of the associated hydraulic system, and therefore the fluid contained therein is not put under pressure, that is, for example, no braking action is exerted and at the same time, the coupling means13are coupled with the coupling counter-means29.

Preferably, the coupling counter means29are shaped as a parallelepiped portion with at least partly curvilinear section.

The coupling counter-means29are preferably integrally formed on the thrust lever2and hence protruding towards the gripping lever7, shaped as a protuberance or operating pin, suitable for coupling into one of the coupling means13.

In this way, by the coupling counter-means29coupled to the coupling means13of the adjustment means9, the gripping lever7and the thrust lever2are made integral during the angular actuation stroke A.

In fact, the adjustment means9, as said, are turnably associated to the gripping lever7; to this end there are provided side surfaces25or walls, protruding from a first end30of the gripping lever7, which house and axially delimit the adjustment means9(FIG. 4).

The side surfaces25, in fact, delimit a seat22obtained along the direction of development of the gripping lever7, that is, recessed between the two side surfaces25.

According to the present invention, seat22houses the adjustment means9.

According to the present invention, moreover, the side surfaces25are arranged substantially parallel to one another and define two tines17which further protrude towards the thrust lever2.

Preferably, tines17are obtained by comprising a rectilinear portion and a rounded or curvilinear end, for better rotation of the gripping lever7when it is connected to the thrust lever2.

Tines17turnably house a second rotation pin18, for obtaining the coupling with the thrust lever2, as illustrated hereinafter.

Favourably, the second pin18is arranged transversally relative to the gripping lever7and to the thrust lever2and is parallel to the first pin10.

Moreover, seat22is laterally open towards the thrust lever2, so that the adjustment means9exhibit, or face, the coupling means13thereof towards the thrust lever2and the coupling counter-means29.

According to the present invention, the adjustment means9are housed into seat22, in a turnable manner by the first pin10, so as to adjust the position thereof and thus adjust the distance between the gripping lever7and handlebar35.

Thus, the first pin10turnably supports the adjustment means9into seat22.

According to the present invention, moreover, the adjustment means9are fully housed into seat22transversally to the gripping lever7, that is, between the side surfaces25.

In fact, the adjustment means9, even though they are fully housed between the side surfaces25, protrude along the radial direction thereof outside of the gripping lever7, as can be seen inFIGS. 1,3and7.

In fact, the adjustment means9substantially are a cylindrical structure, centrally hollow for housing the first pin10, and having an outer side surface12, or skirt12, wherein there are obtained radially recessed regions, that is, seats, which define the coupling means13, and operating tips, as illustrated in detail hereinafter.

In accordance with the present invention, the rotation of the adjustment means9is suitable for selecting the coupling between one of the selectable coupling means13and the coupling counter-means29, that is, for allowing the coupling between the coupling counter-means29and a desired one of the coupling means13.

The possibility of providing for different possible coupling configurations between the adjustment means9and the coupling counter-means29allows adjusting the position of the gripping lever7relative to the thrust lever2and thus relative to handlebar35.

Thus, along the axial direction of the cylinder of the adjustment means9, the adjustment means9themselves are fully comprised within the seat22defined by walls substantially parallel to each other, that is, they are comprised between the planes defined by the side surfaces25themselves, whereas along the axial direction, the same adjustment means9externally protrude at least partly from the gripping lever7.

In accordance with the present invention, as said, the adjustment means9exhibit the side skirt12, which in turn comprises the coupling means13and the operating portions26.

In fact, according to a preferred embodiment of the present invention, the adjustment means9are shaped as a rotating cam9.

On the side surface thereof, the rotating cam9is provided with the coupling means13, shaped as grooves or coupling seats13.

The rotating cam9is provided with at least one coupling seat13, which allows the gripping lever7to be arranged in at least one rest position R.

Preferably, according to the number of coupling seats13, it is possible to position the gripping lever at will in a corresponding rest position R; in other words, it is possible to choose from a plurality of available rest positions.

Preferably, the rotating cam9exhibits a plurality of coupling seats13, for allowing selectively arranging the gripping lever7in a desired one of the different rest positions, that is, different relative angular positions between the gripping lever7and the thrust lever2and thus handlebar35.

The coupling seats13have such profile as to allow a geometrical coupling complementary with the coupling counter-means29, for example a profile with a curvilinear pattern complementary to the curvilinear pattern of the coupling counter-means29themselves, so as to prevent undesired or accidental uncoupling of the adjustment means9.

According to the present invention, therefore, the operating portions26of the adjustment means9are teeth or operating tips26that extend substantially radially; the operating tips26are laterally sided to the coupling seats13and are arranged alternating relative to the coupling seats13themselves.

According to the present invention, the operating portions26, two by two, define each of said coupling means13.

In other words, the side skirt12is a continuous surface comprising the operating tips26, spaced with the coupling seats13.

In other words, the adjustment means9comprise the coupling seats13and the operating tips26, each of said coupling seats13being comprised between two respective operating tips26.

According to the present invention, the coupling seats13are obtained at different depths relative to the axis of rotation of said rotating cam9, that is, at a different radial distance from pin10, for allowing the angular positioning variable at the user's will between the gripping lever7and the thrust lever2.

Seen in section, therefore, the rotating cam9exhibits a shape, that is, an outer perimeter, substantially as an irregular dial, wherein the coupling seats13extend towards the centre of the cam at different depths, that is, each coupling seat13, relative to the adjacent seats, is arranged at a different distance from the axis of rotation of the rotating cam9itself.

In other words, the rotation hole11is arranged in the rotating cam9so that the circular profiles defined by the radial distances of the coupling seats13from hole11form a series of circumferences having the same centre in hole11, but having a different radius.

According to the present invention, each coupling seat13geometrically and selectively couples with the coupling counter-means29, or operating pin of the thrust lever2, for changing the distance between the gripping lever7and handlebar35at will.

In fact, according to the depth of the coupling seat13, the coupling counter-means29penetrate in the coupling seat13of the rotating cam9selected by the operator, more or less deeply, thus allowing a more or less wide apart position of the gripping lever7relative to handlebar35, that is, relative to the thrust lever2.

Moreover, the operating portions26or operating tips26, by their structure, define and delimit the coupling seats13, thus contributing to the geometrical coupling, that is, forming the side abutment surfaces of the coupling seats13themselves, which interfere with the coupling counter-means29and prevent accidental uncoupling.

At the same time, the operating portions26are surfaces suitable for receiving a twisting torque, from example from the motorcyclist's fingers, which puts the rotating cam9in rotation about the first pin10, for selecting the desired coupling seat13and selectively defining the distance between the gripping lever7and handlebar35.

According to the present invention, therefore, each operating portion26, which receives the twisting torque for adjusting the position of the gripping lever7, is integrally comprised between the coupling seats13and structurally defines the coupling seats13themselves, that is, it is at the same time a surface suitable for receiving an operating action of the operator and a surface which produces the geometrical coupling with the coupling counter-means29and thus also produces the coupling and the abutment of the coupling counter-means29in the selected coupling seat13of the rotating cam9itself.

In this way, since the rotating cam9is integral with the gripping lever7, when the gripping lever7is in rest position R and the coupling counter-means29are in abutment in one of the coupling seats13of the rotating cam9, the gripping lever7itself is in a corresponding angular position predetermined by the depth of the coupling seat13itself; in fact, the deeper the seat, the deeper the insertion of the coupling counter-means29into the seat itself, and vice versa, this allowing the gripping lever7to be more or less “closed” towards handlebar35.

According to the present invention, the first end30of the gripping lever7is provided with a first hole21, suitable for housing the first pin10and for cooperating therewith for turnably holding the rotating cam9into seat22.

In fact, the rotating cam9is inserted into seat22so that the rotation hole11and the first hole21are axially aligned and after that, the rotating cam9is locked into seat22itself by the first pin10inserted in the first hole21and in hole11of the cam itself.

Moreover, the thrust lever2and the gripping lever are assembled and turnably coupled by the second rotation pin18.

In other words, as said, the second pin18allows the turnable coupling between the thrust lever2and the gripping lever7.

According to the present invention, moreover, each of tines17exhibits second coupling holes23that cooperate with the second pin18for connecting the two levers.

Correspondingly, the thrust lever2exhibits coupling holes24, for allowing the turnable coupling between the thrust lever2itself and the gripping lever7by the second pin18inserted in the second holes23and in the coupling holes24.

Holes24are suitable for being axially aligned within said second holes23and allowing the insertion of the second pin18.

Tines17thus are inserted into a provided recessed region36or recessing portion of the thrust lever2, shaped conforming, that is, complementary to tines17, that is, with a curvilinear portion, for allowing the rotation thereof without hindrances.

The second pin18exhibits at a first end a holding head34, of radial dimensions suitable for allowing the abutment of the holding head against the outer surface of one of tines17, and preventing the release of the second pin18.

Device1further comprises stopping means27arranged opposite the holding head34; the stopping means27are suitable for axially constraining the second pin18when it is inserted into the second holes23and in holes24, that is, when the gripping lever7and the thrust lever2are turnably associated.

Preferably, the stopping means27comprise a snap ring suitable for cooperating with an annular grove28obtained at a second end of the second pin18.

Thus, the holding head34and the stopping means27lock the second pin18into holes23and into holes24, actually preventing the disconnection of the gripping lever7from the thrust lever2.

As said, according to the present invention the gripping lever7is actuable along an angular adjustment stroke C, opposite said angular actuation stroke A.

The angular stroke C is obtained by a rotation about the second pin18, for obtaining a release of the selected coupling means13from the coupling counter-means29.

By turning the gripping lever along the adjustment stroke C, the rotating cam9disengages from the coupling counter-means29.

At this point, it is possible to rotate the rotating cam9itself about the first pin10so as to select the desired coupling seat13, and thus the desired depth of the coupling seat13itself.

In accordance with a preferred embodiment, the rotating cam9exhibits an operating tip126protruding from the body of the rotating cam9by such extension as to produce a mechanical stop action on the rotation of the rotating cam9itself (FIG. 8b).

The operating tip126is suitably arranged between the minimum depth coupling seat13and the maximum depth coupling seat13.

In fact, the operating tip126has such length as to interfere with the coupling counter-means29; in this way it is possible to avoid the case where, by rotating the rotating cam9, a maximum depth coupling seat13(corresponding to a minimum adjustment of the angular actuation stroke A) changes into an adjacent minimum depth coupling seat13(corresponding to a maximum adjustment of the angular actuation stroke A), or vice versa.

Thus, by providing the operating tip126, it is possible to avoid sudden changes from a minimum adjustment extreme to a maximum adjustment extreme.

For example, therefore, when the maximum depth coupling seat13is selected, a further rotation in counterclockwise direction (seeFIG. 8b) is prevented; in this case, to select the desired minimum depth coupling seat13, it will be necessary to rotate the rotating cam9in clockwise direction until the position of the minimum depth coupling seat13coincides with the position of the coupling counter-means29.

The selection of the desired coupling seat13precedes the step where the gripping lever7itself is returned along the angular adjustment stroke C, that is, towards handlebar35, in rest position R and thus carries out the coupling of the coupling seat13itself to the coupling counter-means29.

The return of the gripping lever7is obtained by special elastic means20,120, as illustrated in detail hereinafter.

Once such coupling has been carried out, the new rest position R of the gripping lever7selected by the user is obtained.

Thus, at least one portion of the rotating cam9is directly accessible and can be influenced from the outside for adjustment, for example by the motorcyclist's fingers.

In other words, at least one portion of the rotating cam9is visible from the outside, thus allowing quick access for adjusting the position of the lever relative to handlebar35.

The cam portion directly accessible by the user, for the rotation thereof and the lever adjustment, as said above, protrudes laterally rather than transversally from the gripping lever7, relative to the development direction of the gripping lever7itself.

Moreover, the protruding cam portion also exhibits surfaces comprising the coupling means13, that is, the seats, and the operating portions26.

In other words, when a coupling seat13of the cam engages in the coupling counter-means29, that is, when the gripping lever7is in rest position R or actuated along the angular actuation stroke A, at least one of the remaining coupling seats13of the rotating cam9laterally protrudes from the gripping lever7, that is, outside substantially towards handlebar35, along for example with the two operating tips26that laterally define and delimit it.

In fact, device1exhibits the gripping lever7, the thrust lever2and the rotating cam arranged between the two levers, laterally protruding from the gripping lever towards handlebar35rather than transversally from the gripping lever7, in a region, or recess, of the system comprised of the gripping lever7, the thrust lever2and the cylinder-piston unit, which is particularly protected.

In other words, the adjustment means9, that is, the cam, are arranged between the gripping lever7and the coupling counter-means29of the thrust lever2as if they were arranged between “anvil and hammer”, where “anvil” means the thrust lever2and in particular, the coupling counter-means29whereas “hammer” means the gripping lever7.

According to the present invention, moreover, device1comprises elastic contrast means20,120housed into seat22(FIGS. 8,9) suitable for elastically and constantly influencing the second operating means7for allowing a return, that is, for carrying out the return of the gripping lever7to the angular rest position R.

The elastic means20,120are preferably axially associated to the rotating cam9by coupling to the first pin10(FIGS. 10,11).

In other words, the rotating cam9and the elastic means20,120are associated to one another in seat22and afterwards fixed to the gripping lever7by the first pin10and to the thrust lever2as described hereinafter.

When the gripping lever7is actuated along the angular adjustment stroke C, the elastic means20,120are suitable for constantly stressing the gripping lever7to return to the rest position R.

Thus, by the elastic means20,120it is allowed the return, that is, the recall to the selected angular rest position R, after the gripping lever7has been rotated for releasing the rotating cam9from the coupling counter-means29.

In other words, the elastic means20,120are suitable for allowing the return to the selected angular hole position R when the gripping lever7is actuated along the angular adjustment stroke C, for releasing the rotating cam9and adjusting the position of the gripping lever7.

Preferably, the elastic means20,120exhibit a portion31, at least partly annular, wherein the first pin10inserts, that is, suitable for axially engaging with the first pin10.

Portion31for example is circular or hook-shaped, or curved.

Moreover, the elastic means20,120exhibit a first end32,132suitable for interfering with the thrust lever2.

According to a preferred embodiment, the elastic means20comprise a traction spring20which exhibits a substantially cylindrical spring body42and comprising the first end32, for coupling with the thrust lever2(FIGS. 8 and 10).

Preferably, the thrust lever2exhibits a special cylindrical housing43, suitable for housing the spring body42of the traction spring20therein.

Preferably, housing43is a through hole obtained in the thrust lever2, for allowing the assembly of the elastic means20.

Housing43of the thrust lever2is provided with a suitable hooking portion, for coupling the first end32to the thrust lever2itself.

The traction spring20therefore couples with the first pin10by portion31and with the thrust lever2by the first end32; in this way, when the gripping lever7is rotated along the angular adjustment stroke C, the traction spring20tends to extend, elastically deforming and thus to recover its non-deformed shape and therefore return the gripping lever7itself to the rest position R.

According to a further alternative embodiment, the elastic means120comprise, as said, the first end132(FIGS. 9,11).

Preferably, the first end132is inserted in a holding seat39and interferes with the walls of said holding seat39during the angular adjustment stroke C, for example moving in abutment on one of the side surfaces thereof (FIGS. 9 and 11).

Moreover, the elastic means120exhibit a second end133suitable for engaging into the corresponding holding recess38obtained into seat22and which interferes with the walls of said holding recess38, during the angular adjustment stroke C.

The second end133is associated to the thrust lever7, whereas the first end132is pre-loaded so as to allow the return to the angular rest position R when the second operating means7impart the adjustment movement along the angular adjustment stroke C, that is, so as to carry out the function of returning the gripping lever7to the rest position R.

According to the present invention, the elastic means120preferably comprise a helical spring, that is, a torsion spring, having the first end133that engages in a portion of seat22and the second end132that engages in a portion of the thrust lever2, jointed by the annular central portion31suitable for being inserted into said first pin10.

In accordance with a further embodiment of the present invention, the thrust lever2exhibits a portion15, that is, a travel end, suitable for abutting against a corresponding portion of the gripping lever7.

Favourably, portion15is comprised in the recessed region36, so that the tines17are housed in the same recessed region36and therefore that at least one of tines17meets portion15at the end of the angular adjustment stroke C.

Thus, the gripping lever7has tines17inserted in the recessed region36of the thrust lever2and is pivoted to the thrust lever2itself: the rotation of the gripping lever17is thus limited by the travel end portion15.

In fact, when the gripping lever7is rotated along the angular adjustment stroke C, at least one of its tines17moves in abutment against portion15, thus limiting the width of the adjustment stroke C itself.

Favourably, a recessed region36is obtained on each of the two opposite faces of the thrust lever2and each of them comprises a travel end portion15, so that both tines17have an angular adjustment stroke C limited by portions15themselves.

In this way, the elastic means20,120are subject to an elastic stress limited by the presence of the travel end portion15, during the adjustment stroke C, so that no yield or non-elastic deformation of the elastic means20,120themselves occurs, for example due to an excessive rotation of the gripping lever7itself, along the adjustment stroke C (seeFIGS. 1,1a,8,8a,9).

Therefore, device1in accordance with the present invention advantageously allows minimising the excessive overall dimensions of the adjustment means of the rest position R of the gripping lever, in the transversal direction relative to the gripping lever itself.

Advantageously, in fact, the cam portion that receives the twisting torque from the user is integrated with the cam portion that contributes to the coupling with the thrust lever2, thus allowing considerable reduction of the axial overall dimensions, that is, transversally relative to the main direction of development of the gripping lever7, of the system for adjusting the position of the gripping lever7relative to handlebar35.

According to a further advantageous aspect thereof, in the only surface or side skirt12there are integrated two surfaces, that is, the coupling surface, or the cam seats, and the thrust surface for the adjustment rotation, or the cam tips, thus allowing considerable and advantageous reduction of the axial overall dimensions of the adjustment device, with evident economical and aesthetic advantages.

In this way, moreover, the cam is very advantageously hidden and protected from accidental shocks, or from items raised during the drive such as stones and mud, in a recess defined by the handle or grip of the handlebar and by the thrust lever and gripping lever together, even though it is at the same time advantageously accessible in quick and effective manner by the user wishing to adjust the cam position, the cam itself in fact facing the motorcyclist, that is, the direction opposed the driving direction.

In fact, since such adjustment devices are normally arranged in the outermost and most exposed portion of the motorcycle, during a fall, one of its particularly protruding portions may abruptly collide with the ground, thus causing the breakage or deformation of the adjustment device or of its handlebar support and fixing structure.

Such damages could imply serious consequences for the motorcyclist's safety, for example preventing an effective braking action.

Advantageously, however, the device according to the present invention is carefully protected by the gripping lever, while remaining easily accessible by the user for adjustments.

Advantageously, moreover, the resistance of the brake fluid which is compressed while braking, or the counter-pressure exerted on the transmission portion8, is evenly discharged on the thrust lever2, for example partly on eyebolt19and not directly on the rotating cam9, since the coupling counter-means29are a portion of said thrust lever2which is different from said transmission portion8, that is, the directrix along which the thrust of the gripping lever7acts on the thrust lever2differs from the directrix along which the actuation of the transmission portion8acts on the cylinder-piston unit; in this way, the rotating cam9and the first pin10are prevented from harmful thrusts, which tend to tilt or in any case stress the first pin10relative to the expected operating position.

According to a further advantageous aspect thereof, moreover, the thrust lever2is integrally formed with the coupling counter-means29, thus allowing considerable advantage during the assembly of the adjustment device1.

Advantageously, moreover, the elastic means20,120or the spring that allows the gripping lever to automatically return to the rest position R after it has been stressed for adjustment, are directly associated to the cam during assembly, thus allowing considerable reduction of the difficulties connected to the assembly of this return system.

In fact, the provision of cam and thus rotation pin10not directly stressed by transmission portions of the actuation movement of the gripping lever to the cylinder-piston unit, advantageously allows the use of elastic means, such as a traction, helical or torsion spring, directly associated to the first rotation pin10.