FR2779102A1 - Dual control system for driving school vehicles, does not require complicated machanical linkages - Google Patents

Abstract

The pupil uses a pedal (17) connected to a simple hydraulic cylinder (33) and the teacher uses a separate but identical pedal (18) connected to a master hydraulic cylinder (39). The teacher's master hydraulic cylinder (39) contains a floating piston (43) in addition to the normal piston (42) and the pupil cylinder connection (36) is made between these two pistons such that the teacher has supervisory control over the hydraulically operated clutch (1)

Description

The present invention relates to a device for dual control of a

  motor vehicle member, in particular a declutching or accelerating member, of the type comprising: - two pedals capable of being actuated in the direction of depressing, from a rest position, respectively by a instructor and by a student, - means of functional connection between each of the pedals and said member, so as to control the latter as a function of the position of the pedals. A dual control device of this type is generally provided in triplicate on vehicles intended for driving schools, at the rate of one specimen intended for acceleration, one specimen intended for

  is braking and a copy for declutching.

  In the current state of the art, the means of functional connection between each of the pedals ensuring the same functions, intended to be actuated respectively by the student and by the instructor, and the member to be controlled by action on these pedals comprises a articulated linkage of mechanical connection between these two pedals, and this linkage is sometimes difficult to produce and to be housed among the other components of the vehicle, especially since it must be provided in triplicate. Its conformation is necessarily linked to a specific type of vehicle, which prevents standardization. In addition, such a linkage can generate noise, 2s introduce a certain imprecision in the transmission of the instructions, and limits the possibilities of dissociation between the instructions coming

  instructor and student respectively.

  The object of the present invention is to remedy these drawbacks, in particular as regards the clutch and 3o accelerator pedals, it being understood that the present invention can also be applied to the control of the braking, for which we however, generally accommodates the aforementioned drawbacks insofar as, in particular, vehicles are generally pre-equipped for driving on the right or on the left while keeping the same location for the brake booster, actuated mechanically by the two brake pedals; it is understood, however, that the present invention could also

  apply to the brake control.

  The dual control device according to the invention, of the type indicated in the preamble, more particularly intended for the control of a declutching or accelerating member but which can thus also be suitable for controlling the braking member, characterized in that the pedals are mechanically independent of each other, so as to be able to occupy different positions, and in that the functional connection means are suitable for controlling said member as a priority as a function of the position of the monitor pedal at least when it is more

  depressed as the student's pedal.

  In such a case, the fact that the instructor or the student depresses his pedal has no effect on the other pedal, which retains its rest position, which makes it possible, in certain embodiments of the invention, and in particular when it is a question of controlling an acceleration member, of making available to the monitor wider intervention possibilities than those offered by a linkage mechanically linking the pedals, that is to say of

  give full priority to the monitor.

  The means of functional connection between each of the pedals and the member to be controlled can remain mechanical but, preferably, they are hydraulic, in particular in the case where said member is a declutching member, or electrical and electronic, in particular in the case where said member is an acceleration member, which avoids all the difficulties inherent in the design of the multiple linkages of the dual control devices of the prior art, as well as the noises and inaccuracies of control that they can generate, and facilitates furthermore the dismantling of the components specific to the dual control, that is to say of the components of the device specific to the monitor, when it is a question of equipping the vehicle, to

  resell it second-hand to an individual.

  Thus, in a hydraulic embodiment, the functional connection means may comprise: - a hydraulic control transmitter for the monitor, comprising a blind cylinder, sealed, fixed relative to the vehicle, said cylinder having a longitudinal axis, a first end transverse open and a second transverse end closed, a first transverse piston mounted for longitudinal sliding in the cylinder and o10 mechanically connected to the monitor pedal through said first transverse end so that the depressing of the monitor pedal causes a translation longitudinal of the first piston inside the cylinder towards the second transverse end thereof and vice versa, and a second transverse piston mounted for longitudinal sliding in the cylinder and arranged floating between the first piston and the second transverse end so as to delimit a first sealed chamber with the first piston and a second sealed chamber with the second transverse end of the cylinder, - a hydraulic control transmitter for the pupil, comprising a 2 o blind, sealed cylinder, fixed relative to the vehicle, said cylinder having an axis longitudinal, a first open transverse end and a second closed transverse end, a transverse piston mounted for longitudinal sliding in the cylinder and mechanically connected to the pupil's pedal through said first transverse end so that the depressing of the pedal of the pupil causes a longitudinal translation of the piston inside the cylinder towards the second transverse end of the latter and vice versa, the piston delimiting a sealed chamber with the second transverse end of the cylinder, 3 0 - a hydraulic receiver of actuation of said member, - a hydraulic connection conduit from the second chamber of the transmitter for the instructor with the hydraulic receiver, opening into the second transverse end of the cylinder of the transmitter for the instructor, - a hydraulic connection duct from the chamber of the transmitter for the student with the first chamber of the transmitter for the monitor, opening on the one hand into the second transverse end of the cylinder of the transmitter for the student and on the other hand between the first and second pistons of the transmitter for the monitor, at least in a position of the first piston corresponding to the rest position of the monitor pedal,

  - a hydraulic fluid filling said chambers and said conduits.

  The hydraulic connection conduit of the transmitter chamber for the student with the first transmitter chamber for the instructor can lead into this chamber in a position such that, whatever the position of the first piston, the communication with this chamber is maintained, so that the effects resulting from the depressing of the two pedals accumulate, but provision is preferably made, in the case of this embodiment of the invention, for this connection conduit to open into the first chamber in the immediate vicinity of the first piston in the position thereof corresponding to the rest position of the monitor pedal, and that this piston has a skirt extending longitudinally opposite the second transverse end of the corresponding cylinder so that a longitudinal movement of this piston towards it sealingly closes the mouth of the conduit, so that, as soon as the monitor pushes its pedal from the rest position, the student's pedal becomes inoperative and that, in the case of a declutching command, the instructor assumes sole control of this command. In an electrical and electronic embodiment, the functional connection means advantageously comprise: - a potentiometer for the monitor, linked to the pedal for the monitor and capable of emitting an electrical signal characteristic of the position thereof, - a potentiometer for the student, linked to the pedal for the student and capable of emitting an electrical signal characteristic of the position thereof, - an electronic processing unit receiving and comparing the signals from the potentiometers for the monitor and for the pupil, respectively, and emitting an actuation signal of said member as a function of said comparison, said actuation signal depending exclusively on the potentiometer signal for the monitor at least as long as said comparison reveals a depressing of the pedal for the upper monitor to that of the pedal for the pupil, and of the signal of the potentiometer for the pupil at least as long as the potenti ometer for the monitor emits a

  characteristic signal of the rest position for the monitor pedal.

  Depending on the case, provision may be made for the control signal to depend exclusively on the pupil's potentiometer signal as long as said comparison reveals that the pedal for the pupil is depressed less than that of the pedal for the instructor, which allows the latter to intervene only in a manner analogous to a further depressing of the pupil's pedal, or else to provide that the control signal depends exclusively on the signal from the monitor potentiometer as soon as the monitor pedal leaves its rest position, that is to say when the potentiometer for the monitor emits a signal revealing that the pedal has been depressed, which gives total control, for example of acceleration, to the monitor

  that the latter decides to depress his pedal.

  Other characteristics and advantages of a device according to

  the invention will emerge from the description below relating to a few

  nonlimiting examples of implementation, as well as the accompanying drawings

  which form an integral part of this description.

  Figures 1 to 3 schematically illustrate the embodiment, according to the invention, of a double clutch release device using hydraulic connection means, in three comparative states

  depressing the student pedal and the monitor pedal.

  FIG. 4 schematically illustrates the embodiment, according to the invention, of a device for dual acceleration control, using electrical and electronic connection means. FIG. 5 illustrates, in the form of a curve, the variation of the engine speed as a function of the respective depressing stroke of the pupil's and instructor's pedals according to a first example of

  operation of the device illustrated in FIG. 4.

  Figures 6 and 7 show the curves similar to that of Figure 5 in the case of a second example of operation of this device and in two hypotheses of comparative state of depressing of the two pedals. Firstly, reference is made to FIGS. 1 to 3, where a clutch 1 is illustrated diagrammatically comprising a flywheel 2 of axis 3, a pressure plate 4 coaxial with the flywheel 2 and juxtaposed with it according to the axis 3, and a clutch disc 5 coaxial with the flywheel 2 and the pressure plate 4 and interposed between the latter along the axis 3. The flywheel 2 and the pressure plate 4 are integral, rotating around 2 0 of the axis 3, of an output shaft not shown of the engine, while the clutch disc 5 is integral in rotation, around the axis 3, of an input shaft also not shown of a gearbox. In a clutch 1 rest state, elastic means such as a diaphragm 6, also of axis 3, elastically urging the pressure plate 4 along axis 3 towards the flywheel 2 hold the clutch disc 5 under axial compressive stress between the latter, which ensures mutual joining by friction with respect to a rotation about the axis 3; this state is illustrated in FIG. 1. However, from this state of rest, a disengaging lever 7 which is articulated on the motor around an axis 8 offset from the axis 3 and arranged in a perpendicular plane to it and cooperates with the diaphragm 6 by means of a clutch stop 9 allows, when a thrust is applied to it along an axis 10, parallel to the axis 3, to separate the pressure plate 4 of the flywheel 2 so as to release the clutch disc 5, that is to say to separate it from the flywheel 2 and from the pressure plate 4 with respect to a rotation about the axis 3. This declutching state is illustrated in FIGS. 2 and 3 and constitutes an unstable state, in the sense that the cessation of the application of the aforementioned thrust to lever 7 causes the clutch 1 to return automatically to its resting state, which is the engaged state of attachment of the clutch disc 5 with the flywheel

  motor 2 and the pressure plate 4 opposite a rotation about the axis 3.

  To cause the lever 7 to apply said thrust along the axis 10, causing disengagement, there is provided a hydraulic receiver 11 comprising a blind cylinder 12 of axis 10, presenting towards the lever 7 an open end 13, and at the opposite an end 14 into which opens

  a sealed conduit 15 for hydraulic connection.

  1] 5 Inside the cylinder 12 is mounted to slide along the axis a piston 16 which defines a sealed chamber 67 with the end 14, inside the cylinder 12, and bears integrally, opposite to this end 14, along the axis 10, a rod 68 disposed along this axis, leaving the cylinder 12 through the end 13 and pressing against the lever 7, along the axis 10, under conditions such as translation of the piston 16 along the axis 10 towards the end 13, under the effect of an introduction of hydraulic fluid inside the chamber 67, results in the application to the lever 7 of the thrust causing the disengagement, against an elastic stress applied to the lever 7 for example by the diaphragm 6, which tends to bring the piston 16 from the end 13 towards the end 14 of the cylinder 12, with reduction of the volume of the chamber 67, by the effect of a thrust applied by the lever

  7 to rod 68 in the appropriate direction.

  These arrangements are known in themselves to a person skilled in the art, and are not characteristic of this embodiment of the present invention, except for the hydraulic nature of the receiver 11, including the supply to the chamber. 17 in pressurized hydraulic fluid causes disengagement while the cessation of this supply and the possibility for the hydraulic fluid to leave the chamber 17 are accompanied

automatically from a clutch.

  To allow a student or an instructor to trigger the clutch, each of them is provided with a respective pedal 17, 18, carried by a respective lever 19, 20 mounted to pivot, relative to the body not referenced vehicle, around an axis

  respective 21, 22, generally horizontal.

  Between the respective pedal 17, 18 and the respective articulation axis 21, 22, each lever 19, 20 has a respective articulation axis 23, 24, by means of a respective linkage 25, 26 simply shown diagrammatically under the shape of a yoke, on a rod 26, 27 for actuating a transmitter

respective hydraulics 28, 29.

  The levers 19 and 20 are identical in their dimensioning S15 in particular as regards the relative positions of the pedals 17, 18, of the axes 21, 22 and of the axes 23, 24, as well as the linkages 25, 26, so that '' identical depressing of the pedals 17 and 18 from a rest position, resulting in an identical pivoting around the respective axis 21, 22 relative to the vehicle body, results in an identical displacement of the rods 26 and 27, relative to the vehicle body, in translation in the same longitudinal direction shown diagrammatically by an axis 30 of the rod 26 and an axis 31 of the rod 27. The axes and 31 are approximately horizontal and symmetrically arranged one of the other with respect to an average vertical plane 32 of the body of the

  vehicle, with respect to which these two axes 30 and 31 are fixed.

  The transmitter 28, thus associated with the pedal 17 for the pupil, comprises a blind cylinder 33, longitudinal, cylindrical of revolution around the axis, fixed integrally to the vehicle body. This cylinder 33 has on the side of the rod 26 an open transverse end 34 allowing the passage of this rod 26 and on the opposite side a transverse wall into which opens a hydraulic connection conduit 36. Inside the cylinder 33, the rod 26 integrally carries a transverse piston 37 which delimits with the wall 35, inside the cylinder 33, a sealed chamber 38 sealingly connected to the conduit 36. In a position of rest of the pedal 17, illustrated in FIG. 1, the piston 37 occupies its position furthest longitudinally from the wall 35, corresponding to a maximum volume of the chamber 38, and a thrust applied forwards to the pedal 17, with reference to a direction of forward movement of the vehicle, results in a translation of the piston 37 along the axis 30, inside the cylinder 33, in a direction going from the end 34 towards the wall 35, this is ie o10 in a direction of reduction of the volume 38 and flushing of the hydraulic fluid

  contained in this chamber towards conduit 36.

  The transmitter 29 comprises a blind cylinder 39 oriented longitudinally, having a generally cylindrical shape of revolution around the axis 31, and carried integrally by the vehicle body like the cylinder 33. The cylinder 39 has a transverse end 40 open to allow the passage of the rod 27 and, opposite, a transverse end closed by a transverse wall 41 which is further from the transverse end 40 than the wall 35 is from the end 34, and into which the duct 15 opens. Internally, the cylinders 33 and 39

  2 0 have the same cross section.

  Inside the cylinder 39, the rod 27 integrally carries a transverse piston 42 mounted for longitudinal sliding inside the cylinder 39, the rods 26 and 27 having the same longitudinal dimension and the pistons 37 and 42 having the same cross section so that the same thrust applied either to the pedal 17 or to the pedal 18 from the respective rest position, illustrated in FIG. 1 also with regard to the pedal 18, results in a displacement identical longitudinal of the pistons 37 and 42 inside the corresponding cylinder respectively 33, 39 and, for reasons which will appear later, upon the expulsion of an identical quantity of hydraulic fluid respectively from the cylinder 33, and more precisely from the chamber 38 thereof, and from the cylinder 39, under conditions which will also appear below. Between the transverse piston 42 and the transverse wall 41, another transverse piston 43 is arranged, meanwhile mounted floating and defining inside the cylinder 39 on the one hand a sealed chamber 44 for receiving hydraulic fluid, with the piston 42 , and on the other hand

  sealed chamber 45 for receiving such a fluid, with the wall 41.

  Thus, the conduit 15 opens via the wall 41 in the chamber 45 and hydraulically connects the latter to the chamber 17 of the hydraulic receiver 11. The conduit 36 opens meanwhile in the cylinder 39 inside the chamber 44, between the two pistons 42, 43, when the piston 42 occupies its position corresponding to the rest position

pedal 18.

  More precisely, the conduit 36 opens flush with the piston 42 is when the latter occupies this position, and the piston 42 bears integrally, longitudinally towards the open end 40, an annular skirt 46 of revolution around the axis 31 and closing the mouth 47 of the conduit 36 inside the chamber 44 as soon as the piston 42 leaves, by moving towards the wall 41, its position corresponding to the rest position of the pedal 18,

2 o as shown in Figure 3.

  The respective volumes of the chambers 38 and 45 are defined by the longitudinal spacing between the piston 37 and the wall 35 and by the longitudinal spacing between the piston 43 and the wall 41, respectively, taking into account the identity of the cross sections of the cylinders 33 and 39, and are at least equal, each, in the state of the clutch device illustrated in FIG. 1, that is to say when the pedals 17 and 18 occupy their rest position and the clutch 1 is in the engaged state, with the difference between the volumes that the chamber 67 presents respectively when the clutch 1 is in the engaged state and when it is in the disengaged state. The volume of the chamber 44 in the rest state of the pedals 17 and 18 is indifferent, since the spacing between the two pistons 42 and 43 is sufficient for

  the mouth 47 is actually located longitudinally between them.

  Chambers 38, 44, 45, 67 as well as conduits 15, 36

  are permanently filled with hydraulic fluid.

  Under these conditions, if the student applies a push to the pedal 17 from the rest state and if the pedal 18 of the monitor remains in the rest state, as shown in FIG. 2, the piston 37 moves towards the wall 35 inside the cylinder 33, which results in a reduction in the volume of the chamber 38, from which the hydraulic fluid is expelled towards the chamber 44 of the cylinder 39. As far as inside the latter, the piston 42 remains stationary, the volume of the chamber 44 increases in relation to the reduction in volume of the chamber 38, by longitudinal displacement of the piston 43 towards the wall 41, which causes a reduction in the volume of the chamber 45, from which a volume of hydraulic fluid identical to that which is expelled from the chamber 38 is expelled via the conduit 15 towards the chamber 67, which causes by increasing the volume of the latter a distancing of the piston 16 relative to the end 14 of the cylinder 12 and consequently quent the application by the rod 68 of a thrust to the lever 7 in conditions suitable for causing disengagement, as illustrated in FIG. 2. If, subsequently, the pupil releases the thrust which he applied to the pedal 17, the aforementioned elastic return means, acting on the lever 7, bring the rod 68 and the piston 16 into a state corresponding to the minimum volume of the chamber 17, which expels from the latter the hydraulic fluid which was thus introduced into the latter, which returns to the chamber 45 by means of an increase in the volume thereof by displacement of the piston 43 in the direction of a distance from the wall 41. Insofar as the piston 42 remains stationary, it follows from a reduction in the volume of the chamber 44 from which the hydraulic fluid is expelled through the conduit 36 towards the chamber 38, by means of a translation of the piston 37 in the direction of a distance from the wall 35 and the return of the flow pedal striping 17 in the rest position illustrated in FIG. 1. It can be seen that the variations in volume of the chambers 17, 45, 44 and 38 are directly related to

  given the substantially incompressible nature of the hydraulic fluid.

  If, now, the monitor applies to the pedal 18 a push forward, from the rest position illustrated in Figure 1, the piston 42 moves inside the cylinder 49 towards the wall 41 of that -this, by closing by the skirt 46 the mouth 47 of the conduit 36 as shown in FIG. 3. From this moment, the student can no longer apply pressure to the pedal 17, which thus remains coercively in the position rest, insofar as the hydraulic fluid cannot escape from the chamber 38 and from the conduit 36. The chamber 44 then has a fixed volume since the hydraulic fluid cannot escape from it either, and the piston 43 moves in unison with the piston 42, in the same direction and with the same longitudinal stroke, driving out of the chamber 45 a volume of hydraulic fluid directly linked to this common stroke. The hydraulic fluid expelled from the chamber 45 is transmitted through the conduit 15 to the chamber 67, with an effect of

  declutching identical to that which has been described with reference to FIG. 2.

  When the thrust applied to the pedal 18 ceases, the hydraulic fluid is again expelled from the chamber 67 under conditions identical to those which have been described with reference to FIG. 2, and returns to the chamber 45 o, by l intermediary of the piston 43 and of the chamber 44 still closed in leaktight manner, it causes the piston 42 to return to its position corresponding to the rest state of the pedal 18, that is to say the return of this pedal 18 in this state of rest. When the piston 42 reaches the corresponding position, the mouth 47 of the conduit 36 inside the chamber 44 is again open, and the entire device returns to the state described in

reference to figure 1.

  Thus, the instructor permanently retains control of the declutching, whether or not the pupil has already applied to the pedal 17 a thrust in the direction of declutching; indeed, the closure of the mouth 47 of the conduit 36 in the chamber 44 occurs as soon as the monitor applies a push to the pedal 18 from the rest position thereof, whether or not the student has started to apply a push to the pedal 17. Therefore: - if the pedal 17 is still in the rest state while the monitor begins to apply a push to the pedal 18 from the rest position, the device operates as described with reference to Figure 3, the chamber 44 retaining the same volume during the entire operation of the device; - If the student has started to apply a push to the pedal 17, pushing it away from its rest position before the instructor applies a push in the same direction to the pedal 18, the hydraulic fluid expelled from the chamber 38 relation to the stroke of the pedal 17 from its rest position has reached the interior of the chamber 44 before the thrust applied to the pedal 18 causes, by displacement of the piston 42, the sealed closure of the mouthpiece 47 but as soon as the thrust applied to the pedal 18 begins, this mouthpiece 47 is closed and the chamber 44 maintains a constant volume; in such a case, the action of the monitor on the pedal 18 is reflected, at the level of the clutch 1, by a complement brought to the initial action of the student on the pedal 17 and the monitor can thus intervene freely by example to cause a complete disengagement if the student has not pressed enough on his pedal 17 to cause disengagement at the time of a gear change, just as he can intervene to disengage for example when the student, confusing the accelerator pedal with the brake pedal accelerates in circumstances in which it should brake, or when the student completely forgets to disengage to change speed. The hydraulic embodiment of the invention has just been described is more particularly suitable for controlling the declutching, but it is understood that it can also be produced in hydraulic form

  a brake command or an acceleration command.

  The electrical and electronic embodiment of the invention which is illustrated in FIGS. 4 to 7 and will now be described is more particularly suitable for controlling the acceleration, but it could also be adopted in the case of the brake control or in the case of declutch control. FIG. 4, to which reference will now be made, illustrates at 48 and 49 respectively an accelerator pedal intended for the student and an acceleration pedal intended for the instructor. Each of these pedals is carried by a lever 50, 51 articulated on the vehicle body around a respective horizontal axis 52, 53, the geometry of the levers 50 and 51 being

  identical between the respective pedal 48, 49 and the respective axis 52, 53.

  According to the respective articulation axis, each lever 50, 51 is placed in functional connection with a respective potentiometer 54, 55, the two potentiometers 54 and 55 being identical so that, for the same position of the respective pedal 48, 49, the two potentiometers 54, 55

  emit an identical electrical signal, characteristic of this position.

  This applies equally to the rest condition of the pedals 48 and 49, that is to say the position they occupy in the absence of thrust applied forward by the student and by the instructor , that at a position in which the pedals 48, 49 are depressed forward, with reference to the direction

  vehicle forwards, from this rest position.

  The two potentiometers 54, 55 are connected by a respective line 56, 57 to an electronic unit 58 whose function will be described, and which is itself connected by a line 59 to the electronic unit 60 for controlling the throttle valve 61 and injectors 62 of the vehicle. This electronic unit 60 exists on most modern vehicles and does not undergo any modification with a view to implementing the present

  invention, so that it will not be described further.

  The intermediate electronic unit 58 contains an electronic processing unit which receives by lines 56, 57 the signals emitted respectively by the potentiometers 54 and 55, compares these signals and emits towards the unit 60, by the line 59, an actuation signal which, in a predetermined manner, depends on the signal emitted respectively by one or the other of the potentiometers 54, 55, it being understood that the dependence relationship between the output signal and the input signals can be predetermined in different ways, in order to give in different ways

  priority to the instructor over the student.

  A first example of the operating mode of the device illustrated in FIG. 4 is shown diagrammatically in FIG. 5, it being understood that the production of the processing unit contained in the housing 58 for this purpose

  falls within the normal abilities of those skilled in the art.

  In FIG. 5, the acceleration which results from the position of the pupil's pedal 48 or would result from this position is expressed in terms of engine speed, on the one hand in solid lines. priority in certain circumstances, and in dotted line the acceleration which results from the action of the is monitor or would result from this if the student did not have priority in certain circumstances, which corresponds to the signals emitted respectively by the potentiometer 54 and the potentiometer 55 and reflects in a one-to-one manner that the position of the pedal 48, 49 respectively associated; the acceleration actually obtained, which corresponds to the signal sent by the electronic unit 58 to the electronic unit 60, has also been indicated in a strong line, in solid line or in dotted lines depending on whether this acceleration is that which corresponds to the signal emitted. by the student or the one who corresponds to the signal emitted by the instructor, leaving in a thin line, respectively continuous or interrupted, the accelerations corresponding respectively to the position of the pedal 48 and to the position of the pedal 49 remaining without influence on the signal sent to the electronic unit 60 due to the priority given in this respect respectively to the signal emitted by the potentiometer 55 of the monitor and to the

  signal emitted by the student's potentiometer 54.

  It can thus be seen, with reference to FIG. 5, that if the student applies a push to the pedal 48 while the pedal 49 is at rest, the signal emitted by the intermediate electronic unit 58 towards the motor control unit 60 is identical to the signal emitted by the potentiometer 54 at least as long as the pedal 49 of the monitor remains at rest and that the potentiometer 55 emits a corresponding signal; just as the signal emitted by the potentiometer 54, the signal emitted by the box 58 increases as the pedal 48 is depressed and, if the pupil stops depressing this pedal 48 while maintaining it in position, the signal emitted by the housing 58 stabilizes, it being understood that the speed of the engine itself stabilizes when this signal stabilizes. If the monitor observes this level of engine speed and considers that this speed should be increased, he presses on the pedal 49 which thus leaves the rest position but, as long as it has not reached the depressing position of the pedal 49 corresponding to the depressing position of the pedal 48, that is to say as long as the signal emitted by the potentiometer 55 is not at least equal to the signal emitted by the potentiometer 54, this action of the monitor on the pedal 49 remains ineffective; it is only when the pedal 49 begins to depress more than the pedal 48, and therefore that the signal emitted by the potentiometer 55 becomes greater than the signal emitted by the potentiometer 54, that the signal emitted by the potentiometer 55 becomes substitutes the signal emitted by the potentiometer 54 to constitute the output signal from the intermediate electronic unit 58, and cause a further increase in the engine speed after the level imposed by the student, possibly up to a new level determined by a signal of output from box 58 identical to the output signal from

potentiometer 55.

  In other words, according to this operating mode, the position of the pedal 49 has priority over the position of the pedal 48 when the engine speed requested by action on the pedal 49, by the monitor, is

  higher than the speed requested by the student, by pressing the pedal 48.

  The realization, for this purpose, of the electronic unit of the box 58 falls within the normal aptitudes of a person skilled in the art and can vary to a large extent, in particular depending on the way in which, on the envisaged vehicle, the order issued the accelerator pedal when it is single acts

on the engine speed.

  In a vehicle in which, as illustrated, the position of the throttle valve 61 is controlled by an auxiliary actuator from a set point from the accelerator pedal then processed and amplified by a computer of the electronic unit 60, the analog signals originating respectively from potentiometer 54 and potentiometer 55 and representative of the position of the respectively associated pedal 48, 49 are processed by a comparator of the electronic unit of the intermediate unit 58, which comparator changes state at output when the signal from the potentiometer is greater than the signal from the potentiometer 54 and returns to its initial state when the signal from the potentiometer 54 is less than the signal from the potentiometer 55 of a certain hysteresis, intended to attenuate a "pumping" effect of the signal output of the comparator, constituting the signal sent to the housing 60 by the line 59, during small variations in position of the pedals. In such a case, an additional device may be necessary to eliminate the risk of going from a degraded mode during a transition phase between the priority granted, to constitute the output signal of the electronic unit of the intermediate box 58, at the signal from the

  potentiometer 54 or the signal from potentiometer 55.

  When, not shown, the order from the accelerator pedal acts directly on the member to be controlled, such as the throttle valve 61 or a load lever, while a feedback signal is sent to the computer contained in the electronic unit 6 for the management of the various parameters of the motor, provision is made for the addition of an additional actuator controlled, independently of the mechanical connection, by an electrical signal corresponding to that of the signals originating respectively from the potentiometer 54 and the potentiometer 55 which is the highest, to act on the throttle valve 61. For this purpose, the aforementioned voltage comparator controls or not, depending on its output state, a mechanical or static relay with two contacts (NO or NO + NF) which transmits the retained signal, namely the signal emitted by the potentiometer 54 or the signal emitted by the potentiometer 55, as a set value, to the additional actuator, which controls the rotation of the throttle valve 61, the feedback signal of which is transmitted to the computer in the box 60. However, a more advanced mode of assigning priority to the signal emitted by the potentiometer 55 actuated by the pedal 49 of the monitor can be provided. the signal emitted by the potentiometer 54 associated with the student's pedal 48, and such a mode has been illustrated in FIGS. 6 and 7 where the same code has been kept as in FIG. 5 to designate the acceleration or the engine speed requested by the student by acting on the pedal 48, the acceleration or the engine speed requested by the monitor by action on the pedal 49, and the acceleration or the engine speed requested at the output of the intermediate electronic unit 58 , by transmission of an appropriate signal to the electronic unit 60 or, as the case may be, to an additional actuator of the throttle valve 61. In the example illustrated in FIGS. 6 and 7, the monitor takes priority as soon as it is placed cement of his accelerator pedal 49, that is to say effective speed control even if his request in this regard is less than that of the student, and no longer only if it is greater than that of 20 l student: Thus, we illustrated in Figure 6 the case in which the student, whose pedal 48 is initially in the rest state as well as the pedal 49 of the monitor, gradually depresses the pedal 48 then stabilizes that -this in a determined depressing state, which causes an increase in the engine speed then a stabilization of the latter at a value corresponding to the depressing of the pedal 48. If, then, the monitor begins to depress the pedal 49 hitherto kept in the idle state, by sending at the output of the potentiometer 55 a signal lower than the output signal of the potentiometer 54, the effective engine speed, determined by the signal 30 sent by the intermediate electronic unit 58 to the electron box ique 60, gradually decreases until its value reaches the value corresponding to the depressing position of the pedal 49 and, if the monitor continues to depress it until its depressing exceeds that of the pedal 48 , the signal emitted at the output of the intermediate electronic unit 58 increases again, like the output signal of the potentiometer 55, until it exceeds the output signal of the potentiometer 54 and then stabilizes at a value greater than that of the level requested by the student when the

  monitor stops depressing pedal 49 and keeps it stationary.

  If, on the other hand, and as shown in FIG. 7, the monitor stabilizes the pedal 49 in a position corresponding to a requested engine speed lower than that requested by the student, the effective engine speed, determined by the output signal from the intermediate electronic unit 58, drops until it stabilizes at the level corresponding to the output signal emitted by the potentiometer 55, that is to say at the position in which the monitor has

stabilized the pedal 49.

  The realization, for this purpose, of the electronic unit of the intermediate box 58 also falls within the normal capacities of a person skilled in the art. Such a person skilled in the art will easily understand that the embodiments of the invention which have just been described constitute only non-limiting examples, with respect to which we can provide

  many variants without departing from the scope of this invention.

Claims (8)

  1. Double control device for a member (1; 60 to 62) of a motor vehicle, in particular a declutching or accelerating member, of the type comprising: s - two pedals (17, 18; 48, 49) capable of being actuated in the direction of insertion, from a rest position, respectively by a monitor and by a student, - means (11, 15, 28, 29, 36; 54 to 59) functional connection between each of the pedals (17, 18; 48, 49) and said member (1; 60 to 62), so as to control the latter as a function of the position of the pedals (17, 18; 48, 49),   characterized in that the pedals (17, 18; 48, 49) are mechanically independent of one another, so as to be able to occupy different positions, and in that the functional connection means (11, 15, 28 , 29, 36; 54 to 59) are suitable for controlling said member (1; 60 to 62) in priority as a function of the position of the pedal (18; 49) of the monitor at least when   it is more depressed than the pupil's pedal (17; 48).   2. Device according to claim 1, characterized in that the functional connection means (11, 15, 28, 29 36) are hydraulic,   2 0 especially in the case where said member (1) is a declutching member.   3. Device according to claim 2, characterized in that the functional connection means (11,15, 28, 29, 36) comprise: - a transmitter (29) for hydraulic control of the monitor, comprising a blind cylinder (39) , sealed, fixed relative to the vehicle, said cylinder (39) having a longitudinal axis (31), a first open transverse end (40) and a second closed transverse end (41), a first transverse piston (42) mounted to slide longitudinal in the cylinder (39) and mechanically connected to the pedal (18) of the monitor through said first transverse end (40) so that the depression of the pedal (18) of the monitor causes a longitudinal translation of the first piston ( 42) inside the cylinder (39) towards the second transverse end (41) thereof and vice versa, and a second transverse piston (43) mounted for longitudinal sliding in the cylinder (39) and arranged floating between the first piston (42) and the second transverse end (41) so as to delimit a first sealed chamber (44) with the first piston (42) and a second sealed chamber (45) with the second transverse end (41) of the cylinder (39), a hydraulic control transmitter (28) for the student, comprising a blind cylinder (33), sealed, fixed relative to the vehicle, said cylinder (33) having a longitudinal axis (30) 1, a first open transverse end (34) and a second closed transverse end (35), a transverse piston (37) mounted for longitudinal sliding in the cylinder (33) and mechanically connected to the pupil's pedal (17) through said first end transverse (34) so that _5 depressing the pedal (17) of the student causes a longitudinal translation of the piston (37) inside the cylinder (33) towards the second transverse end (35) of that -ci et inversem ent, the piston (37) delimiting (35) the cylinder (33), - a hydraulic receiver (11) for actuating said member (1), - a conduit (15) for hydraulic connection of the second chamber (45) of the transmitter (29) for the monitor with the hydraulic receiver (11), opening into the second transverse end (41) of the cylinder of the transmitter (29) for the monitor, - a conduit (36) for hydraulic connection of the chamber (38) of the transmitter (28) for the student with the first chamber (44) of the transmitter (29) for the monitor, opening on the one hand into the second transverse end (35) of the cylinder (33 ) of the transmitter (28) for the student and on the other hand between the first and second pistons (42, 43) of the transmitter (29) for the instructor, at least in a position of the first piston (42) corresponding to the rest position of the pedal (18) of the monitor, - a hydraulic fluid filling said chambers (38, 44, 45) and said conduits (15, 36).   4. Device according to claim 3, characterized in that the conduit (36) for hydraulic connection of the chamber (38) of the transmitter (28) for the student with the first chamber (44) of the transmitter (29 ) for the monitor opens in the immediate vicinity of the first piston (42) occupying said position, and in that the first piston (42) comprises a skirt (46) extending longitudinally opposite the second transverse end (41) of the cylinder (39) of the transmitter (29) for the monitor so that a longitudinal displacement of this first piston (42) towards this second transverse end (41) closes this conduit (36) in a sealed manner. 5. Device according to claim 1, characterized in that the functional connection means (54 to 59) are electrical and electronic, is in particular in the case where said member (60 to 62) is an acceleration member. 6. Device according to claim 5, characterized in that the functional connection means (54 to 59) comprise: - a potentiometer (55) for the monitor, linked to the pedal (49) for the monitor and capable of emitting a electrical signal characteristic of the position thereof, - a potentiometer (54) for the pupil, linked to the pedal (48) for the pupil and capable of emitting an electrical signal characteristic of the position thereof, - an electronic processing unit (58) receiving and comparing the signals from the potentiometers (55, 54) for the instructor and for the pupil, respectively, and transmitting an actuation signal of said organ (60 to 62) as a function of said comparison, said actuation signal depending exclusively on the potentiometer signal (55) for the 3rd monitor at least as long as said comparison reveals a depressing of the pedal (49) for the monitor superior to that of the pedal (48) for the pupil, and sig of the potentiometer (54) for the pupil at least as long as the potentiometer (55) for the instructor emits a signal characteristic of the   rest position for the monitor pedal (49).   7. Device according to claim 6, characterized in that the actuation signal depends exclusively on the potentiometer signal (54) for the student as long as said comparison reveals a depressing of the pedal   (48) for the pupil lower than that of the pedal (49) for the instructor.   8. Device according to claim 6, characterized in that the actuation signal depends exclusively on the signal from the potentiometer (55) for the monitor as soon as the potentiometer (55) for the monitor emits a   signal indicating depressing of the pedal (49) for the monitor.