Abstract:
The electric actuator, for the control of the clutch and/or sequential gearbox in motor vehicles, comprises an electric motor ( 11 ) and a mechanism ( 9, 10, 31, 32 ) for transforming rotary motion into linear motion of the actuator element ( 2, 22, 33, 52, 67 ), and has a thrust crank or at least one cam ( 9, 29, 50 ) that performs a complete rotation returning to its starting position, whether it be the control for the clutch ( 1, 48 ), the gearbox ( 27, 47 ), or both. Also, the said cam is advantageously made in the form of a template ( 9, 29, 50 ), fashioned in a plate ( 8, 21, 28, 49, 68 ) sliding in a guide ( 14, 30, 69 ), in which a crank stud ( 10 ) is positioned rotating with the action of the said electric motor ( 11, 45 ). The said template ( 9 ) for operating the clutch being advantageously shaped in accordance with the specific requirements of the application (R, D, F, I) to optimise the loads. Combined, compact embodiments of the two actuators ( 47, 48 ) for the clutch and sequential gearbox are comprised, as well as: mechanical disconnecting safety mechanisms ( 53, 60 ) for operation of the gearbox lever; sensing devices ( 71 ) for measuring the actuator forces for the clutch; finally, a locking mechanism ( 78, 79, 80 ) to keep the clutch disengaged during multiple gear changes in quick succession.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This is a continuation-in-part application which claims priority from PCT/IT01/00179, published in English, filed Apr. 10, 2001, based on Italian patent Application No. MO2000A000072, filed Apr. 11, 2000; this application also claims priority from Italian Application No. MO2000A000072, filed Apr. 11, 2000.  
         TECHNICAL FIELD  
         [0002]    The invention concerns: electric actuators for controlling the clutch and/or the sequential gearbox in motor vehicles, in which the release of the friction clutch occurs by means of the action of a device equipped with a template; similarly, the actuation of the sequential gearbox is achieved by means of a template of a different actuator, the two actuators possibly being coupled for the simultaneous control of the said clutch and sequential gearbox.  
         BACKGROUND OF THE INVENTION  
         [0003]    Prior art already comprises actuator devices for sequential gearboxs consisting of hydraulic cylinders in which the pressure acting in the said cylinders selects, in sequence, the higher or lower gear.  
           [0004]    The said actuators consist of two single acting cylinders, whose pistons are connected to each other on the same stem on the opposite side from the pressure chamber. A drain connection is positioned in the middle between the cylinders and the pistons when in their neutral position; the pressure chambers are controlled by three-way control valves which connect each chamber, alternatively to the high pressure line, for actuation, or the discharge line to end actuation on that side; the central position of the stem with two pistons is obtained by means of two cups with collars on the pressure chamber side, which when subjected to pressure in both chambers define a fixed central position, by means of the collars and appropriate stroke limiters.  
           [0005]    Prior art also comprises mechanical actuators for clutch control in motorcycles, in which the mechanical control acts on a lever, by means of a rack-and-pinion transmission, which moves the clutch plate; the return stroke is ensured by the springs of the clutch plate. A manual hydraulic control is also used consisting of a single acting hydraulic cylinder acting on the control rod of the clutch plate, fed by a small pump connected to the manual control lever operated by the user.  
           [0006]    The need for both manual and automatic operation is felt particularly when the gearbox is operated remotely. In fact, in the case of motorcycles, the dual operating mode, both of the gearbox but more importantly of the clutch is seen as significant safety feature.  
           [0007]    With remote control operation the command which carries out the sequential gearbox, to operate correctly also has to operate the clutch, that is, the said lever with pinion and rod with rack, or the manual hydraulic control, with single acting cylinder, have to be remote controlled; because of the way they are configured they do not enable indifferently automatic or manual operation, that is with remote control.  
           [0008]    Also, in the field of motor vehicles, prior art comprises an actuator to operate the clutch consisting of an electric motor which by means of a pinion coupled to a portion of crown gear turns a lever which acts by means of a rod on the clutch; the said lever is connected to a spring which compensates the opening force of the clutch. Moreover, such an actuator needing to invert the sense of rotation of the electrical motor during the operating cycle of the clutch, does not enable the sense of rotation of the said lever to be made not predetermined, as it has an obligatory direction. Furthermore, the inversion of the sense of rotation is a limiting factor for the speed of operation of the actuator.  
           [0009]    Also for the gearbox there are electric motors, possibly with speed reducing mechanisms, that control the gear shift drum directly or actuate the gear lever in sequential gear boxes.  
           [0010]    Also, the high powers of modern motorcycle engines require a considerable force to be exerted by the rider to operate the clutch.  
           [0011]    Such prior art may be subject to considerable improvement with a view to the possibility of making actuators for clutches and sequential gearbox with a low cost and simple operation.  
           [0012]    From the foregoing emerges the need to resolve the technical problem of inventing a configuration of the actuator controlling the clutch and/or the sequential gearbox which is simple to construct and which is reliable, the two actuators possibly being coupled in construction and operation.  
         SUMMARY OF THE INVENTION  
         [0013]    The invention resolves the said technical problem by adopting: an electric actuator for controlling the clutch and/or the sequential gearbox in motor vehicles, comprising an electric motor and a mechanism for transforming the rotary motion into linear motion of the actuator element, characterised in that, it comprises a crank mechanism or at least one cam, made to perform a complete rotation returning to the starting position, be it the clutch control, the gear change control, or both.  
           [0014]    Adopting, in a preferred embodiment: constituting the said cam, as the mechanism for transforming the rotary motion into linear motion, a template, fashioned in a plate sliding on a corresponding guide, in which is positioned a crank stud made to rotate by the said electric motor.  
           [0015]    Adopting in a second preferred embodiment: the said template being shaped in accordance with the application to optimise the forces.  
           [0016]    Adopting, in a further preferred embodiment, in the case of the clutch actuator: the plate with the template having a spring to compensate the forces generated by the internal springs of the clutch.  
           [0017]    Adopting, in a further preferred embodiment: the actuator element consisting of a hydraulic pump connected to the plate containing the said template.  
           [0018]    Adopting, in a further preferred embodiment of the clutch actuator: the actuator element consisting of a metallic cable connected to the said plate containing the said template.  
           [0019]    Adopting, in a further preferred embodiment of the sequential gearbox actuator: the template consisting of two profiles which are each parallel and tangential to the circumference traced by the stud, and of two profiles which are coaxial and tangential to the said circumference in a direction parallel to that of the guide and perpendicular to the said parallel profiles.  
           [0020]    Adopting also, in a further preferred embodiment of the gearbox actuator: the actuator element connected to the plate containing the template in an elastic manner so as to allow over-run of the control stroke.  
           [0021]    Adopting also, in a further preferred embodiment of the gearbox actuator: a mechanical disconnecting mechanism, with pre-loaded elastic element, positioned between the said electric actuator and the control pin of the sequential gearbox; the said disconnecting mechanism having an operating direction which may be either axial or rotational.  
           [0022]    Further adopting, in another form of embodiment for the gearbox actuator: the gearbox rod centred mechanically on the guide of the actuator by means of counter-acting springs.  
           [0023]    Adopting, in a further form of embodiment of the gearbox actuator: a sensor for detecting the neutral position of the template of the actuator.  
           [0024]    Further adopting, in another form of embodiment: a position sensor on the rotating element of the mechanism for transforming the rotary motion into linear motion.  
           [0025]    Also adopting, in a further embodiment: the crank having a sphere engaging in a notch to determine the neutral position.  
           [0026]    Adopting, furthermore, in another form of embodiment of the clutch actuator: a sensor to measure the closing force of the said clutch; the said sensor possibly consisting of a load cell rigidly connected to the actuator rod of the clutch or of a sensor that measures the pressure of the hydraulic fluid when the clutch is actuated hydraulically. Adopting, finally, in a further preferred embodiment of the clutch actuator: a rigid unidirectional connection between,the sliding plate with the template and the rigid actuator rod of the clutch; furthermore it has a tooth to block the said rod or extremity, to position it against the shoulder or in the groove made in it: the said tooth is actuated in insertion by means of an electromagnet with neutral position normally disengaged.  
           [0027]    The advantages obtained with this invention are: operating the control of the friction clutch by means of the template is economical and correct operation is ensured, and it is versatile in terms of where it is positioned in the vehicle; the crank stud is offloaded of the residual tension or thrust generated by operating the clutch due to the presence of the compensating springs; furthermore, the force generated by the electric motor is reduced and optimised by the geometry of displacement of the template; importantly, also, both the hydraulic actuator and that operated by the metal cable are extremely economical.  
           [0028]    Furthermore, the sequential gearbox actuator is of very simple construction and does not have any of the complications of the prior art hydraulic actuators; the said actuator may be easily and economically manufactured and proper operation is assured. Furthermore, the template actuator for operating the sequential gearbox is highly versatile, as it may be indifferently power assisted or manually operated and it may be coupled to clutch operating actuator, to operate the clutch in a suitably synchronised manner, thereby ensuring proper operation of both controls. Furthermore, when the gearbox actuator is coupled to the clutch actuator, and which rotates with it, it is still possible to control the clutch, to allow the degree of slippage necessary for the dynamic requirements of the vehicle, even with the automatic control, that is, managed by the vehicle control logic, as well as, naturally, with the manual intervention of the driver, without having to operate the gear lever. Also, both the actuator for just the clutch and the two actuators for clutch and gearbox may be fitted to the vehicle after it is manufactured, thereby implementing an advantageous improvement to the said vehicle; finally the assembly may be carried out by the user because the said actuator or actuators are easy and economical to install.  
           [0029]    Finally, with the use of the locking tooth with electromagnetic control of the lever in the clutch actuator, it is possible to keep the clutch of the vehicle disengaged even in situations where multiple gear changes are required, generally when changing down, in a short space of time and without the need to engage the clutch with each change of gear. In this case a further advantage is the possibility of stopping the vehicle with a gear selected and to select any gear without the vehicle moving with engine on. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]    Some embodiments of the invention are illustrated, purely by way of example, in the twelve tables of drawings attached in which:  
         [0031]    [0031]FIG. 1 is the longitudinal section of the hydraulically operated clutch control actuator with template, as described in the present invention;  
         [0032]    [0032]FIG. 2 is a perspective view, with the cover missing from the template, of the actuator of FIG. 1;  
         [0033]    FIGS.  3  to  8  are schematic representations of the template and of the crank stud of a clutch actuator in the various positions during the operating cycle, starting from disengagement to reengagement;  
         [0034]    [0034]FIG. 9 is a diagram showing the forces that act on the template and its movement during a stroke;  
         [0035]    [0035]FIG. 10 is the longitudinal section of a sequential gearbox control actuator with template operated by metal wire;  
         [0036]    [0036]FIG. 11 is the longitudinal section of a sequential gearbox control actuator with template, according to the invention;  
         [0037]    [0037]FIG. 12 is the prospective view, with the cover missing from the template, of the actuator in FIG. 11;  
         [0038]    [0038]FIG. 13 is the prospective view of the lever mechanism coupling the control of the sequential gearbox of a motorcycle with the actuator with template, according to the present invention;  
         [0039]    [0039]FIG. 14 is the prospective view of the sequential gearbox and clutch control actuator for a motorcycle, both coupled to the same drive motor;  
         [0040]    [0040]FIG. 15 is the lateral view of a further embodiment of the group of actuators for clutch/gearbox, viewed from the side of the gearbox actuator, without lateral cover and partially sectioned;  
         [0041]    [0041]FIG. 16 is the prospective view of the mechanical axial disconnecting mechanism for the gearbox lever;  
         [0042]    [0042]FIG. 17 is section XVII-XVII of FIG. 15 limited to the sectioned plane;  
         [0043]    [0043]FIG. 18 is a longitudinal prospective view of the group of actuators with a further embodiment of the mechanical disconnecting mechanism showed sectioned, in this case rotational and positioned directly on the pin of the sequential gearbox lever;  
         [0044]    [0044]FIG. 19 is the prospective view of the group of actuators and lever mechanism of the gearbox operation in the previous Figure;  
         [0045]    [0045]FIG. 20 is the side view of the group of actuators for clutch/gearbox viewed from the clutch actuator side, without the lateral cover and partially sectioned;  
         [0046]    [0046]FIG. 21 is the enlarged view of the template and the crank stud of the clutch actuator of the previous FIG., slightly rotated from the neutral position with clutch engaged;  
         [0047]    [0047]FIG. 22 is a view analogous to the previous one of the clutch actuator, but with locking tooth, with electromagnetic control, that keeps the clutch disengaged, pressed against the rigid control lever. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0048]    The figures show:  
         [0049]    [0049] 1 , FIG. 1, the hydraulic control mechanism of the clutch, having pump  2 , with piston  3  of cylinder  4  and reservoir  5 , connected to the pump by means of inlet tubes  6 ;  
         [0050]    [0050] 7 , the connection of the supply tube for the hydraulic fluid to the clutch, here not shown;  
         [0051]    [0051] 8 , the plate in which the template  9  is fashioned coupled to the crank stud  10  made to rotate on command by gear reducer  11 ;  
         [0052]    [0052] 12 , the lever connected, by means of pin  13 , to the said plate and in maintained contact with the said piston  3 ;  
         [0053]    [0053] 14 , the guide of the said plate  8 ;  
         [0054]    [0054] 15 , the reaction cup for the return stroke of the said piston  3 , against the reaction of the compensating spring  16 , adjustable so as to reduce the loads on the mechanism during operation of the clutch;  
         [0055]    [0055] 17 , a sphere pushed by spring  18  to sit indent  19 , so as to define fixed position of the said crank;  
         [0056]    [0056] 20 , FIG. 2, the position sensor of the clutch lever;  
         [0057]    CD, FIG. 4, the initial displacement in the disengagement movement of the clutch and CI, FIG. 8 the final stroke of the engagement movement;  
         [0058]    R, FIG. 9, the point on the diagram indicating the neutral position of the mechanism illustrated in FIG. 3;  
         [0059]    D, the point in the diagram indicating the initial stage of disengagement, illustrated in FIG. 5;  
         [0060]    F, the point in the diagram indicating the complete disengagement, illustrated in FIG. 6;  
         [0061]    I, the point in the diagram indicating the completed engagement, illustrated in FIG. 7;  
         [0062]    G, the loading vector of the compensating spring from I to R, illustrated in FIG. 8, or the unloading vector from R to D, illustrated in FIG. 4;  
         [0063]    [0063] 21 , FIG. 10, a plate with template  9 , analogous to the preceding one but shorter for operation with the metal cable  22  of the clutch control, not shown;  
         [0064]    [0064] 23 , the connecting stem between the said plate  21  and the clamp  24 , holding said cable  22 ;  
         [0065]    [0065] 25 , the spring compensating the forces on the mechanism;  26 , the sheath of the said metal cable.  
         [0066]    The figures also show:  
         [0067]    [0067] 27 , FIG. 11, the control actuator of a sequential gearbox, in which the plate  28 , with template  29 , is made to slide in guide  30 ;  
         [0068]    the said template consists of two guiding profiles  31 , each with axis tangential to the circumference followed by the said crank stud  10  and parallel to each other, as well as of other profiles  32 , coaxial and tangential to the said circumference, in a perpendicular direction to profiles  31  and parallel to the guide  30 ;  
         [0069]    [0069] 33  the rod connecting control lever of the gearbox; the said rod is positioned by counter-acting springs  34 ,  35  in both directions, whereas it is elastically connected with pin  13  to the said plate  28  by means of the over-run compensation springs  36 ;  
         [0070]    S, the positioning hole for the sensor which detects the neutral position of the actuator  27 , to detect manual interventions and to prevent the automatic intervention of the actuator;  
         [0071]    [0071] 37  the fulcrum of rear suspension of the actuator;  
         [0072]    [0072] 38 , FIG. 12, the sensor to detect the position of the control;  
         [0073]    [0073] 39 , FIG. 13, the extension of the said rod  33 ;  
         [0074]    [0074] 40 , the pedal control, on axis C, determining the rotation of the sequential gearbox selector, not shown;  
         [0075]    [0075] 42 , a rod connecting the said pedal control  40  the rod  39 ;  
         [0076]    [0076] 43 , an oscillation arm of the said rods.  
         [0077]    The figures also show:  
         [0078]    [0078] 44 , FIG. 14, the group of two actuators  1  and  27 , for the simultaneous control of the clutch, here hydraulically operated, and the sequential gearbox;  
         [0079]    [0079] 45 , the single electric motor reducer that synchronously activates the pins that couple with the templates  9  and  29 , to act simultaneously and with a single control, from the power assisted control mechanism, not shown;  
         [0080]    [0080] 46 , FIG. 15, the group of two actuators in compact form  47  for the sequential gearbox and  48  for the clutch;  
         [0081]    [0081] 49  the plate in which template  50  is fashioned, analogous to template  29 , but having straight profiles  51  joining profiles  31 - 32  (and  32 - 31 ) following on from each other;  
         [0082]    [0082] 52 , the rigid rod connected rigidly with pin  13  to the said plate  49  and subjected to the centring action of the springs  34  and  35 ;  
         [0083]    [0083] 53 , the mechanical axial disconnecting device rigidly connected to the control lever  54  of the sequential gearbox control: the said disconnecting device consists of a double housing for the preloaded compression spring  55 , in which the external part  56  is rigidly connected to the rod  57 , that is an extension of rod  54 , and the internal part  58  is rigidly connected to the red  54 ;  
         [0084]    [0084] 59 , inclined portions of the said external part to contain and guide the said spring  55  preloaded to a fixed value;  
         [0085]    [0085] 60 , FIG. 18, the rotational disconnecting device, placed between the control lever  61 , to which is connected rod  42 , and the pin  62  for activating the sequential gearbox on axis C;  
         [0086]    [0086] 63 , the rotational spring, between whose end portions  64 , preloaded to a fixed value, are held pin  65 , rigidly fixed to the said arm  61 , and pin  66  rigidly fixed to the gearbox lever  40 , splined on said pin  62 : the lever is rotationally coupled to the said pin  62 .  
         [0087]    Finally, the figures also show:  
         [0088]    [0088] 67 , FIG. 20, the rigid rod rigidly connected to the sliding plate  68  in which there is template  9  for the crank stud  10 ;  
         [0089]    [0089] 69  the guide for the said sliding plate;  
         [0090]    [0090] 70 , an indent for the precise definition of the angle of rotation of the stud  10  for the neutral position;  
         [0091]    [0091] 71  a load cell, to measure axial loads, positioned between the said rod  67  and the extension  72 , to enable a fine adjustment of the moment of engagement of the clutch;  
         [0092]    [0092] 73 , FIG. 22, the extremity of the said rod  67 , in which there is a rigid unidirectional coupling with the said sliding plate  68 : the said connection consists of a rod  74  rigidly connected to the said plate  68  coupled with axial sliding in a corresponding groove  75  made in the rod  67 : during the thrust motion, the shoulder  76  of the said plate  68  and the front surface  77  of the said extremity are in contact;  
         [0093]    [0093] 78 , the locking tooth of the said rod  67 , which presses against an axial shoulder  79  made in said extremity  73 ;  
         [0094]    [0094] 80 , the electromagnet activating the said locking tooth  78 , when in neutral position being disengaged.  
         [0095]    Operation of the hydraulically operated clutch actuator is as follows. The actuator may be placed in any convenient location in the vehicle and has the hydraulic connection  7  with the tube to the actuator cylinder of the clutch, of known type, and the servo control acts with an electric signal to the motor reducer in the moment the clutch is operated. When the command is given the rotation of the crank stud  10  generated by the motor reducer is effected with a speed that rapidly enables the thrust on piston  3  to achieve a response from the clutch suitable to the operating conditions of the vehicle at that moment. The said stud rotating and pushing the template  9  towards the said piston generates the axial movement of the pump  2  that sends pressurised oil through connecting tube  7  to the clutch. In the last portion of rotation of the button  10  the return stroke of the plate is counteracted by the thrust of spring  16  acting on the plate by means of cup  15 , to counteract the forces generated by the springs in the clutch. Finally, sphere  17  entering into the groove  19  selects the neutral position of the said crank stud  10  in contact with the template  9 . In this position the plate is acted only acted on by the spring  16 , preloaded, whereas on the opposite side the forces of the clutch are balanced inside the clutch itself and by the hydraulic connection  6  between the cylinder  4  and the tank  5 .  
         [0096]    Comparing the operation of the actuator described above with the load-displacement diagram the crank stud  10 , FIG. 9, once beyond the neutral position dead-point, FIG. 3, there is a first section CD in which the stud is propelled by the spring  16  without encountering resistance, due to the stroke required by connection  6  for hydraulic sealing: the motion occurs with the maximum acceleration that the inertia of the motor reducer mechanism allows, reaching close to point R; then in the section CD, still under the action of the spring which overcomes the counter forces generated in taking up the slack caused when disengaging the clutch, in the diagram the load passes along line G with a very small displacement passes from R to D. Subsequent displacement, from the position of FIG. 4 to that of FIG. 6 is represented from point D to F in the diagram with a variation in load, acting on the said stud  10 , still under action of the spring  16  for the first half of displacement, and then only subsequently does the motor reducer have to overcome the forces to achieve complete disengagement of the clutch arriving at F: the load that has to be counteracted in normal known clutches has been found to be between 0 and 30 daN. In the subsequent phase of clutch engagement, from FIG. 6 to FIG. 8, the thrust of the clutch from F towards I aids rotation of the crank stud in the first part, then as described for the disengagement, the subsequent section it is of a reduced value due to the difference in the preloading of the springs of the clutch and the compensation spring  16 ; in the last section with displacement CI of FIG. 8 the stud  10  has to overcome the entire force of the spring  16 , passing from point I to point R along load vector G: this displacement occurs at the end of the cycle without affecting it, the load generated by the electric motor reducer may be controlled by the conformation the thrust face of the template  9 . The said template, in the case of a rectilinear or straight face, with respect to the direction of displacement of the plate  8 , has a sinusoidal relationship of the reduction of the tangential load actually acting on the motor reducer, with respect to the load generated by the spring  16 , thereby assisting in reaching the initial position in FIG. 3. From the foregoing emerges the possibility of shaping the face of the template on the side of the compensating spring  16 , but also of  25  with the metal cable  22 , to minimise the torque acting on the motor reducer in the above mentioned displacement CI: the resulting profile has an inclined section with variation of the inclination close to the neutral position. Finally, with this actuator, the profile of the template  9  can be made with a geometry that define displacement relationships for clutch disengagement and engagement that allow specific responses of the clutch to be achieved; this is possible with actuator  1 , whether it rotates in one direction or whether it rotates in both directions, when coupled with the gearbox actuator  27 .  
         [0097]    In the subsequent configuration operation by metal cable  22 , FIG. 3, operation is analogous, with the difference of the pulling action, and not thrust, applied by the said cable, as shown in FIG. 1; the neutral position of the said crank stud  10  is achieved with the play introduced between the extremity of the said cable  22  and the clamp  24  holding the said cable, positioned at the end of the stem  23 : the compensation spring  25  has its maximum load in that position.  
         [0098]    In this way, the shape of the template  9 , as described earlier, may, advantageously have a non linear profile designed to achieve displacement relationships of the plate which vary in function of the positions of the crank stud  10 , which may thereby conveniently be adjusted in function of the forces acting on the mechanism.  
         [0099]    Operation of the sequential gearbox actuator, FIG. 4, is as follows. The power assisted control that acts on the clutch, as described earlier, also acts as control for the sequential gearbox actuator: as the crank stud  10  rotates it engages with one of the two profiles  31  and acting on plate  28  displaces it, the choice of profile depends on the direction of gear selection, either a higher gear or a lower one, and therefore on the sense of rotation of the stud  10 ; the pin  13 , is in turn pushed by plate  28  under the action of the compensation spring  36 , so as to act on the rod  33  connected with rods  40  and lever pedal  41 . The control stroke of the gearbox is shorter than stroke of the said plate  28 , the compensation of the springs  36  ensuring the gearbox stroke is completed, ensuring proper operation.  
         [0100]    The engagement with the guiding profiles  31  of plate  28  is advantageously set after at least a quarter of a rotation of the stud  10  to enable the motor reducer to start in total absence of resistance and, furthermore, to engage with profile  31  with tangential motion so as to avoid shocks; the delay in the activation is also advantageous in its use in conjunction with the clutch actuator, allowing the clutch actuator to intervene before the gearbox actuator. Furthermore the two profiles  32  enable the operator to use the sequential gearbox manually, without the intervention of the power assisted control and the actuator: the stud can remain in its neutral position, shown in FIG. 4, while the plate  28 , moved by the external lever system, pedal  41 , lever  40 , rod  42  and rod of extension  39 , does not encounter obstructions during its stroke, thereby allowing manual operation. Moreover, the configuration of the template  50 , with its straight profiles  51 , makes it easy to operate in all conditions, enabling even a manual change by the driver while the actuator  47  is operating; a further safety feature is the mechanical disconnecting mechanism, in both its axial configuration  53  and its rotational configuration  60 , ensuring a rigid connection between the parts with limited levels of load, in the case of the axial disconnecting mechanism, or limited torque in the case of the rotational disconnecting mechanism. The effect of the disconnecting mechanisms is to allow over-run of the actuator  47  without damaging the sequential gearbox whilst at the same time ensuring that control stroke is completed.  
         [0101]    Operation of the double actuator  1 ,  27 , FIG. 7, is as in the respective single actuators for the clutch and the sequential gearbox: the coupling of the two respective studs is made conveniently with the required phase angle of one with respect to the other, whereas for the sense of rotation of the motor reducer, whilst being indifferent for the clutch control, is not indifferent for the sequential gearbox. The coupling of the two crank studs  10  and their respective plates  8  or  21 , and  28  is in any way possible and very convenient, with the two actuators performing a simultaneous and synchronised control stroke using a single driving device. Consequently a lack of synchronisation between the gearbox and the clutch is always avoided.  
         [0102]    The clutch actuator  48 , as shown in FIGS. 20 and 22, has a rigid control rod  67 , and its extension  72 , separated by load cell  71  which continuously measures the value of the load applied between the actuator  48  and the clutch, here not shown. The resulting signal is analysed by the electronic processor which controls the phase modulation of engagement of the said clutch. An analogous effect of phase modulation of the clutch engagement may also be obtained in the hydraulic control of the clutch as in FIGS. 1 and 2, having in the control tube, that is, downstream of the pump  2  and upstream of the cylinder activating the said clutch, a sensor for measuring the pressure of the hydraulic liquid, which is, as known, proportional to the load on the rod of the clutch.  
         [0103]    [0103]FIGS. 20 and 21 show the indent  70 , a variation of indent  19 , in which the crank stud  10  engages when in its neutral position with clutch engaged allowing a precise positioning of the actuator  48 , by way of the compensating action of the spring  25  on the sliding plate  68  with template  9 .  
         [0104]    Operation of the locking tooth  78 , shown in FIG. 22, is achieved by activating the controlling electromagnet  80  causing the said tooth to engage with the axial shoulder  79  of the extremity  73  of the rod  67 : the said shoulder allows the thrust stroke, but does not allow the reengagement of the clutch thereby enabling the actuator to perform a number of consecutive rotations of the stud  10  without operating the clutch; this possibility is very useful when carrying out more the one gear changes, usually when changing down, enabling the clutch engagement phase to be skipped when changing several gears simultaneously; Once the multiple gear change phase is completed the electronic control processor deactivates the electromagnet, thus enabling the final engagement stroke of the clutch to be carried out.  
         [0105]    In practice the materials, the dimensions and details of execution may be different from, but technically equivalent to, those described without departing from the juridical domain of present invention.  
         [0106]    For instance, though less advantageous, instead of the said linear templates, that is, generating a sinusoidal displacement relationship, thrust crank mechanisms may be used, which in function of the length of the piston rod used approach the said sinusoidal relationship. Furthermore, as an alternative to rod  39  in the gearbox actuator  27  the actuation may be transmitted by means of metal cables. Also, the straight profiles  51  may be in whichever way profiled or curved to join said profiles  31 - 32  (and  32 - 31 ) following on from each other. Finally the axial shoulder  79 , in the case of the locking tooth  78  for keeping the clutch actuator  48  in the open position may be obtained with an annular hole, or even an axial slot, in the said extremity  73 , with an appropriate axial extension to enable an adequate movement in the said slot to compensate the displacement of the rod  67  in the over-runs generated by the sliding plate  68 .