US3667577A

US3667577A - Vehicle speed responsive controls for transmission, clutch and engine

Info

Publication number: US3667577A
Application number: US26305A
Authority: US
Inventors: Charles Terres Weymann
Original assignee: S I D A R O SOC IND DE DISPOSI
Current assignee: S I D A R O SOC IND DE DISPOSI
Priority date: 1969-04-28
Filing date: 1970-04-07
Publication date: 1972-06-06
Anticipated expiration: 1989-06-06
Also published as: FR2041503A5; GB1293207A; ES371968A1; DE2014052A1

Abstract

The present invention relates to an automatic gearbox control device for automobiles which is applicable to any conventional mechanical gearbox and can be coupled to an existing vehicle without any major modification. The control device comprises : a source of pressure fluid, a double-action ratio-changing jack actuated by said pressure fluid through two electrovalves selectively, and an electrical regulating contactor propelled at a speed proportional to that of the vehicle and comprising two terminals selectively supplied with current by said regulator from the vehicle battery for supplying two connections to said electrovalves respectively, each of said connections comprising two contactors in parallel, namely a self-maintaining contactor activated by the ratio-changing member operatively connected to said jack and a maneuver contactor activated by the vehicle clutch i.e. which closes in the de-clutched position. The control device also includes means for automatically idling an associated engine or cutting off the fuel supply thereto during ratio shifting.

Description

United States Patent Weymann 1 June 6, 1972 [5 1 VEHICLE SPEED RESPONSIVE 2,662,621 12 1953 Long ..192/.092 CONTROLS FOR TRANSMISSION, 2,703,636 3/1955 Long 192/.092 CLUTCH AND ENGINE Primary Examiner-Ben amin W. Wyche [72] Inventor: Charles Terres Weymann, Paris, France Attorney-Jacobi, Lilling & Siegel [73] Assignee: S.I.D.A.R.O Societe lndustrielle de Dispositifs Automatiques Robomatic, Oise, [57] ABSTRACT France The present invention relates to an automatic gearbox control device for automobiles which is ap licable to any conven- [22] 1970 tional mechanical gearbox and can b: coupled to an existing {2}} A l, N 26,305 vehicle without any major modification. The control device comprises a source of pressure fluid, a double-action ratiochanging jack actuated by said pressure fluid through two [30] Fore'gn Apphcat'on Pnomy Dam electrovalves selectively,and an electrical regulating contac- Apr. 28, 1969 France ..6913392 impelled a Speed that vehicle and comprising two terminals selectively supplied with current by 52 us. 01 ..192/.0s, 192/092, 192/358, said regulam' mm the vehicle suPPYmg 192/084 74/873 91/189 nections to said electrovalves respectively, each of said con- 51 im. c1. ..B60k 21/00, B60k 29/00 mpmmg cmacwrs in Parallel namely a self 58 Field of Search 192/.062, .092, .08 maintaining acivaed by the atiwhanging member operatively connected to said jack and a maneuver I 56] References Cited contactor activated by the vehicle clutch i.e. which closes in the de-clutched position. The control device also includes UNITED STATES PATENTS means for automatically idling an associated engine or cutting off the fuel supply thereto during ratio shifting. 2,605,874 8/1952 Price ..192/.092 2,620,908 12/ 1952 Orr et al. 1 92/092 9 Claims, 6 Drawing Figures PATENTEDJUN 6 I972 3,661 577 SHEET 1 [IF 3 PATENTEBM 61972 3,667,577 SHEET 20F 3 I l a1 6v h H62 471 76 7c 7 FIG.3 FF

I FIG4 a 1 ,0 M E E A a FIG.5 I

PATENTEDJUH 6 I972 SHEET 3 BF 3 FIG. 6

ZZZ

VEHICLE SPEED RESPONSIVE CONTROLS FOR TRANSMISSION, CLUTCH AND ENGINE The present invention relates to an automatic gearbox control for automobiles.

Automatic controls known up to the present generally require a special gearbox, for example, with an epicyclic gearing, a hydraulic converter, a continuous variator, etcetera, and are generally adaptable only to a vehicle designed for this purpose.

On the contrary, the present invention envisages an automatic control which is applicable to any conventional mechanical gearbox; the automatic control can be coupled to an existing vehicle without any major modification.

On the otherhand, the automatic control according to the invention can be instantly disengaged if desired, simply by operating an electrical switch. The conventional manual gearchange system, which remains unaltered, is thus always available, giving total functional reliability.

Again, a range selector allows optional choice of velocity stages for which the changes in ratio occur, so that the control is adaptable to the preferred driving method of every driver.

Finally, as there is no modification to the vehicles transmission, and in particular there is no free-wheel in the control system, the advantage of engine braking is always present, as in a conventional car.

The automatic control is just as suitable for threeor fourratio touring vehicles as for utility vehicles, lorries or buses which incorporate a larger number of ratios.

A device according to the invention for automatic control device for the mechanical gearbox of a motor vehicle, comprising: a source of fluid at a pressure different from atmospheric pressure; a double-action ratio-changing jack, activable by said fluid, and whose piston rod is connected to a ratio-changing member of the said gearbox; a first and second electro-valves interposed between said source and, respectively, both ends of the cylinder of said jack; and electrical regulating contactor, propelled at a speed proportional to that of the vehicle, and comprising at least one first and one second output terminals, selectively supplied with current by said regulator, from the vehicles battery, for a first and a second range of velocities; a first and second electrical connection, respectively interposed between the first output terminal and the first electrovalve, and between the second output terminal and the second electrovalve, each of the said connections comprising two contactors in parallel, of which one is a selfmaintaining contactor activated by the said ratio-changing member, and of which the other is a maneuver contactor, activated by the vehicle's clutch, and which closes in the declutched position.

Embodiments of the invention will be described with reference to the accompanying drawings, which are given by way of example only.

The drawings show in:

FIG. 1: a diagrammatic view of the device for controlling a two-ratio gearbox;

FIGS. 2,3: the positions for the first and second gear ratios of the de-clutch and self-maintaining switches;

FIG. 4: a diagrammatic view of the connection, by hydraulic connecting-rod, between a gear-change jack and a gearchange lever;

FIG. 5: a supplementary jack used in a device for controlling a four-speed box;

FIG. 6: members which must be added to the device shown in FIG. 1 to ensure control of a four-speed box.

With reference to FIG. 1, there will firstly be described an embodiment of a device which is applied to the control of a gearbox with two speeds only. Generally, of course, automobiles have three or four gear ratios, or even more in the case of lorries, but description is simplified if it is illustrated in the case of a two-speed box. With reference to the following F 168., a description will then be given of the invention applied to gearboxes with more than two ratios.

The device comprises: a gear change control servomechanism 1, a fuel-throttling servomechanism 3, and a clutch servomechanism 5.

Each of these servomechanisms comprises at least one jack or hydraulic piston and cylinder device activated by a fluid at a pressure different from atmospheric pressure. In the embodiment in FIG. 1, all these jacks are pneumatic jacks activated by air, at a pressure below atmospheric pressure, which is stored in a tank 7 connected to a low-pressure tube from the engine.

servomechanism 1 comprises a double-acting jack 9, or ratio-changing jack which, via a piston rod 11, or through a liquid connecting-rod transmission (not shown) controls a member of the gearbox, for example, the lever 13 of the gearbox. Two electrovalves 15,17 allow source 7 to be connected selectively to one or the other end of jack 9. When electrovalve 15 is activated, the piston of the jack and the rod 11 move to the left, and bring lever 13 into a first ratio, indicated by ratio A. When electrovalve 17 is activated, lever 13 comes into the other ratio B. When neither of these electro-valves is activated, a return system (not shown) brings the piston of jack 9 to the center, in the position shown in the Figure.

Ratios A and B are two ratios on the same longitudinal axis and, for example, for the most prevalent velocity ranges, these are the first-second, or else third-fourth gears.

servomechanism 3 likewise comprises a low-pressure jack 19, or fuel-control jack, whose piston rod is connected to the engine's fuel control 21. An electrovalve 23, when it is activated, controls the throttling of the fuel, and therefore the engines deceleration.

In the same way, servomechanism 5 comprises a low-pressure jack 25, or clutch jack, whose piston rod 27 controls a member of the vehicles clutch system, for example, the clutch pedal 29. An electro-valve 31, when it is activated, controls the de-clutching movement (in the direction of arrow D) of the vehicles transmission. servomechanism 5 can advantageously form part of an automatic clutch control system.

The device further comprises a centrifugal regulating system 33, which will be indicated in the following by the term govemor." One input terminal 35 of the governor 33 can be connected by a range switch 37 to one of the poles of the battery. The governor 33 which rotates at a speed proportional to the vehicles road speed, closes an electrical contact between the input 35 and a first output 39 for a first velocity range (e.g. 0-30 km/h), corresponding to ratio AfFor a second velocity range, e.g. above 30 km/h, the centrifugal regulator 33 opens the first contact and completes a second circuit, connecting input 35 to a second output 41.

As will be shown in the following, the governor 33 comprises as many outputs as there are ratios to be controlled on the gearbox. On the other hand, as will likewise be shown, switch 37 may serve as a range selector in order to modify the extent of the different velocity ranges chosen.

The device also comprises a relay for controlling each ratio, in the case of FIG. 1, a relay 43 corresponding to ratio A and a relay 45 for ratio B.

The device finally comprises a first and second set of three switches each.

Switches

47,49,51 of the first set have mobile contacts, controlled by the movements of the gearbox member controlling the changes in ratio. Thus piston rod 11 of servomechanism l is shown diagrammatically as activating the mobile contacts of these switches.

Switches 53,55,57 of the second set have mobile contacts controlled by the movements of the member controlling the clutch, for example, piston rod 27 of servomechanism 5. Switch 47, with three contacts 47a, 47b, 47c, controls the clutch electrovalve 31 in association with the contacts of

relays

43 and 45, which are respectively mounted in parallel with contacts 47a, 47b and 47b, 470, as shown in dotted lines in FIG. 1.

Switch 53 controls the fuel electrovalve 23. The switch 55, or maneuver switch, in association with the switch 49, or selfmaintaining switch, controls electrovalve 15. Switch 57 (maneuver), in association with switch 51 (self-maintaining), controls electrovalve 17.

The different elements are electrically connected together according to the circuits of FIG. 1, which shows the device at dead center.

The device functions as follows: with the engine running and the vehicle stationary, and lever 13 at dead center, the driver closes a feed-switch 59 supplying governor 33 and terminal 47a of switch 47.

By means of circuit 47a,47c,53a, the current activates clutch electrovalve 31. As soon as the clutch starts to travel, piston rod 27 closes contactor 53 so that the current passing through 53a,53b, 61 activates electro-valve 23, cutting off the fuel. Under these circumstances, even if the driver leaves his foot on the accelerator, the engine will idle.

When de-clutching is complete, piston rod 27 closes both contactors 55,57, whose purpose will be described later.

When governor 33 is supplied with current and the vehicle is stationary, the current emerges from the governor by output 39, and activates the coil of relay 43 mounted between the terminals 2,3 of this relay. The contact closes between terminals 1-4 of the relay.

The current emerging from terminal 39 of the governor 33 likewise activates the gear-change electrovalve through

wires

63,63,53, and contactor 55, which is closed, as shown previously. As a result of the opening of electrovalve 15, the piston of jack 9 moves to the left and rod 11 brings lever 13 into the first ratio A, at the same time acting on

contactors

47 and 49.

The mobile contact of contactor 47 is pushed to the left, maintaining contact 47a-47b in force, but breaking contact 47b-57, for arm 47c is retained by a stop 67 in this direction (FIG. 2). The

circuit

47c,53a,53b,61 is therefore broken and deceleration electrovalve 23 is no longer excited. From this moment, therefore, the driver has the opportunity of accelerating normally. For the same reason, the exciter circuit of the clutch electrovalve 31 is likewise broken, making it possible to engage the clutch.

If the vehicle is fitted with an automatic clutch control of the type described, or with a centrifugal clutch, the driver then need only accelerate in order to engage the clutch. On return into the clutch-engaged position, the three contactors 53,55,57 controlled by the piston rod 27 open, but at first, this has no effects since it is no longer in circuit, as was seen above. Contactor 55, closed until now, ensuring that electrovalve 15 was activated, is replaced in this function by contactor 49 which is now closed (FIG. 2) and ensures the continuity of the exciter circuit of electrovalve 15 along the following path: 63 contactor 49 closed 64 65.

The vehicle is thus travelling normally in the first ratio A and, when it reaches the speed provided for the change of ratio, the governor 33 cuts off the current at output 39 and establishes the supply on output 41.

The following operations are then carried out:

current in wire 63 is cut off; relay 43 is de-activated; contact 1-4 of relay 43 is opened; electrovalve 15 is de-activated.

current is established on terminal 41 of the governor 33; relay 45 is activated; contact l-4 of relay 45 is closed.

the closure of contact 1-4 of relay 45, which is in parallel with contact 47b-47c of contactor 47 which is at this point open, activates the de-clutching eIectro-valve 31 which is followed as stated above, by the movement to the right of rod 27, by the closure of contactor 53 causing activation of electrovalve 23, which cuts off the fuel, and by the closure of contactors 55,57.

electro-valve 15 being de-activated, the left-hand part of jack 9 is exposed to the atmosphere, rod 1 1 moves to the right and brings lever 13 to dead center as it activates

contactors

47,49,51.

the whole is at dead center, clutch disengaged, fuel cut off, contactor 47 closed,

contactors

49 and 51 open (FIG. 1).

electrovalve 17 being activated, the right-hand part of jack 9 is put under low pressure, pushing piston rod 11 to the right and causing lever 13 to pass into ratio B.

piston rod 1 1, moving to the right, opens contact 47a,47b and closes contactor 51 (FIG. 3).

contact 47a,47b being open, the clutch electrovalve 31 ceases to be activated, the clutch-engaged position is again adopted, as electrovalve 23 is de-activated by the opening of contactor 53 (piston rod 27 moves to the left.) The fuel is thus no longer cut off. At the same time rod 27 opens contactor 57, but electrovalve 17 continues to be activated via closed contactor 51.

- the car is then travelling normally in ratio B.

If the cars speed drops below the velocity provided for ratio B, and identical procedure takes place, that is, output 41 of the governor 33 ceases to be fed with current, and is replaced by output 39 which activates relay 43, whose contact 1-4, in parallel in open contact 47a,47b, closes and controls the clutch disengagement, while electrovalve 17 ceases to be activated as a result of the lack of current on governor terminal 41.

The range selector 37, connected optionally by the driver, on the first contact 35 of governor 33 or on a second contact 70, allows choice of the vehicle speed at which changes of ratio will occur. For example, in the case of a four-speed box, the changes will occur at 20-40-60 km/h for the first change and at 30-50-80 km/h for the second change.

In order to simplify the description it has been supposed'up to now that the gear-change lever 13, or any other member of the gearbox, was controlled directly from the pneumatic jack 9. According to a preferred embodiment, a hydraulic transmission by fluid connecting rod between jack 9 and lever 13 is used, as is shown in FIG. 4.

Pneumatic jack 9 is fed with low-pressure air by one or other of the electrovalves 15 or 17, as seen above, and its rod 72 activates the piston 74 of an oil master cylinder both of whose ends are connected by

tubes

78,80 to an oil receiver jack 82 whose piston rod 11 activates lever 13.

A tube 84, which incorporates a valve 86, connects both ends of the receiver jack. If valve 86 is opened, the transmission by fluid connecting-rod is eliminated and lever 13 can be operated manually. It will thus be seen that if the automatic control fails, the gear-change can still be used manually. Valve 86 is preferably an electrovalve which closes when the supply contactor 59 of the automatic control (FIG. 1) is closed. Thus one manual operation is enough to activate or de-activate the automatic gear-change control.

Preferably also, the clutch disengagement electrovalve is excited through a relay 87 shown in dotted lines in FIG. 1.

If one considers a range of velocities of four gears, such as that in FIG. 5, in which the gear-change lever 13 is returned to dead center on axis III-IV by a spring, the device shown in FIG. 1 will be suitable without modification for carrying out the maneuvers III-IV and lV-III.

In order to adapt the device according to the invention to a four-speed box, it is sufficient to add an extra jack, or selector jack, 88, which is, for example, a low-pressure pneumatic jack. In this case governor 33 comprises four outputs (FIG. 6), that is outputs 39 and 40 already described (controlling ratios A and B, that is ratios III and IV for the four-speed box), and two extra outputs 90-92 (respectively controlling the first and second ratios I and II).

FIG. 6 does not show the entire device as in FIG. 1, the latter remaining unchanged, only the connector-points H and K on the circuit already described (FIG. 1) being shown, and the extra members controlling the change of gears into first and into second. This may be more fully understood by viewing the governor 33 of FIG. 1 as possessing two

additional output terminals

90 and 92. In fact, applicant has used the same reference numeral to indicate a similar device, thus one need only imagine the

similar input terminals

35 and 39 to the governor 33, thus the governor 33 would be connected, as in FIG. 1, to the control switch 47 (source 59).

In order to control a four speed box, all that is necessary is to connect switch 49 of FIG. 1, to point H of FIG. 6 and to connect switch 51 of FIG. 1 to point K of FIG. 6, switch 53 of FIG. 1 remaining connected to point L.

The gear-shift lever 13 of FIG. 1 is movable from neutral position longitudinally in one or the other of two opposite directions into one or the other of two speed-engaging positions; the gear-shift lever 13 in FIG. 6 is also movable in a transverse direction to a second neutral position from which it may be moved longitudinally in one or the other of two op posite directions into one or the other oftwo additional speedengaging positions. All of this may be done by the same system and in the same manner as described with reference to FIG. 1.

In order to move lever 13 into the second neutral position thereof, the invention provides a piston having a piston rod 98 connected to lever 13. The piston is responsive to fluid pressure controlled by the

additional output terminals

90 and 92 so as to move the lever 13 against the action of the resilient means (not shown) in the transverse direction to the second neutral position thereof, from which the lever will be moved (by piston rod FIG. 11 of FIG. 1) into one or the other of the two speed-engaging positions corresponding to said

additional output terminals

90 and 92. This will be clearly apparent with reference to the discussions found above. Thus, one may imagine that the line from switch 59 to contact 47 A in FIG. 1 is thereby repeated in FIG. 6, thus it is clear FIG. 1 and FIG. 6 can be combined for the shifting of a four-speed transmission.

These extra members in FIG. 6 comprise a relay 94, or firstgear relay, whose coil is activated by the current coming from output 90 of governor 33, and a contactor 96 whose mobile contact is activated by the rod 98 connecting the piston of selector jack 88 to lever 13.

The supply to low-pressure jack 88 is controlled by an electrovalve 100 incorporated in a pipeline 102 linked to the lowpressure air source 7.

A relay 104, identical to relay 94, has its coil symmetrically connected to output 92 (second gear output) of the governor, and is connected to a contactor 106 likewise activated by piston rod 98.

The start of the operation is identical to that described above, that is the engine is de-clutched and the fuel mixture cut back, from circuit 47a,47c,53a, activating the de-clutching electrovalve 31, then electrovalve 23.

At the same time, the vehicle being stationary, output 90 of the governor is under current, and supplies it to the coil of relay 94, whose terminals 3,4 are thus connected to terminal 1.

By means of the circuit output 90 contacts closed (1-4) of relay 94 cable 108, the electrovalve 100 is excited and jack 88 brings lever 31 into alignment 1-" of the range. At the same time, rod 98 closes contact 96, which, by circuit 90 closed contacts l-3 of relay 94 closed contacts 96a-96b-cable 110, puts point H under current.

Referring to FIG. 1, and to the associated description, it will be seen that when point H is put under current, jack 1 is fed through electrovalve l5 and leads lever 13 to position A, that is, towards first for the four-speed range.

When the ratio-change speed provided for the passage from first to second is reached, output 90 ceases to be supplied, that is, point H is no longer under current, bringing about the results described with reference to FIG. 1: de-clutching, cutofi" of fuel, return of lever 13 to dead center.

From this fixed speed, governor output 90 is supplied and, via the symmetrical circuit of relay 104, and of contactor 106, the selector jack electrovalve 100 is again excited in order to keep lever 13 in the alignment III of the range. At the same time point K is put under current by the circuit 92-closed contacts 1-3 of relay l04-closed contact 106.

With reference to FIG. 6 still, it will be seen that when point K is under current, lever 13 is brought into position B, i.e. into the ratio of second on the four-speed range.

For the ratio changes third and fourth, the function is exactly the same as that described with reference to FIG. 1,

respectively, for passing into ratios A and B, it being selfevident that for these two ratios electrovalve 100 of the selector jack 88 is never activated, since it can only be activated through

outputs

90 and 92 of the governor. When jack 88 is not supplied, a return spring normally returns the gear lever 13 into alignment III-IV.

Naturally, the same combination would permit control of a six or eight speed box, the basic elements remaining identical.

I claim:

1. In a motor vehicle having a change speed gear provided with a gear-shift member, a friction clutch, a gas throttle member, and a source of electric current, an automatic gearchanging system comprising: a vehicle speed responsive governor connected to said source and having at least two output terminals corresponding each to one of different speed ratios, respectively; first electromagnetically controlled means operative, when the electromagnet of said first means is energized, to move said clutch from the engaged position into disengaged position; second electromagnetically controlled means operative, when the electromagnet of said second means is energized, to move said throttle member into idling position; third electromagnetically controlled means operative, when the electromagnet of said third means is energized, to move said gear-shift member from its neutral position into one speed-engaging position corresponding to one-of said different speed ratios; fourth electromagnetically controlled means operative, when the electromagnet of said fourth means is energized, to move said gear shift member from its neutral position into another speed-engaging position corresponding to another one of said different speed ratios; first circuit means comprising a first control switch for connecting the electromagnet of said first controlled means to said source; second circuit means comprising a second control switch for connecting the electromagnet of said second controlled means to a point of said first circuit means located between said first control switch and the electromagnet of said first controlled means; third circuit means comprising a control switch and a first holding switch for connecting the electromagnet of said third controlled means to one of said governor output terminals; fourth circuit means comprising a fourth control switch and a second holding switch for connecting the electromagnet of said fourth controlled means to another one of said governor output terminals; first switch-actuating means movable in unison with the axial movements of said clutch, said first switch-actuating means being connected to said second, said third, and said fourth control switches so as to close the same when said clutch reaches said disengaged position thereof; and second switch-actuating means movable in unison with said gear-shift member and connected to said first control switch, and to said first and second holding switches so as to open said first control switch and to close said first and said second holding switches when said gear-shift member reaches any of said speed-engaging positions thereof.

2. A motor vehicle as recited in claim 1, in which said vehicle speed-responsive governor has four output terminals two of which correspond to said one and said other speed ratios and two other of which correspond to two additional different speed ratios, and in which said automatic gear-changing system further comprises fifth electromagnetically controlled means operative, when said electromagnet of said fifth means is energized, to move said gear-shift member from said neutral position thereof to a second neutral position from which said gear-shift member is movable into a speed-engaging position corresponding to one of said two additional speed ratios or into another speed-engaging position corresponding to the other of said two additional speed ratios; fifth circuit means comprising a fifth control switch for connecting said third circuit means comprising said third control switch and said first holding switch to said fifth circuit means; a first relay connected to a first one of said two additional governor output terminals and adapted, when energized through said first output terminal, to connect said fifth circuit means and the electromagnet of said fifth controlled means to said first output terminal, sixth circuit means including a sixth control switch for connecting said fourth circuit means comprising said fourth control switch and said second holding switch to said sixth circuit means; a second relay connected to a second one of said two additional governor output terminals and adapted, when energized through said second output terminal, to connect said fifth circuit means and the electromagnet of said fifth controlled means to said second output terminal, and third switch-actuating means movable in unison with said gear-shift member between said neutral positions thereof and connected to said fifth and said sixth control switches soas to close the same when said gearshift member reaches said second neutral position thereof.

3. An automatic control device for the mechanical gearbox of a motor vehicle, the gearbox comprises a ratio-changing member, the motor vehicle comprises a battery, clutch having a control member, and an engine idler member, said automatic control device comprises;

a source of fluid at a pressure different from atmospheric pressure;

a double acting ratio-changing jack activated by said fluid; said ratio-changing jack piston rod is connected to said ratio-changing member;

first and second electrovalves interposed between said source and, respectively, both ends of said ratio-changing jack cylinder;

an electrical regulating contactor, propelled at a speed proportionate to that of the vehicle and comprising at least first and second output terminals selectively supplied with current by said regulating contactor from said battery, for a first and second range of velocity; I

a first and second electrical connection respectively interposed between said first output terminal and first electrovalve, and between said second output terminal and said electrovalve; each of said connectors comprises two contactors in parallel, one of said contactors is a selfmaintaining contactor activated by said ratio-changing member, said second contactor is maneuver contactor activated by the clutch, said maneuver contactor closes in the declutch position;

a de-clutching single-action jack, activated by said fluid;

said de-clutching jack piston rod is connected to said control member of said clutch;

an electrovalve interposed between said source and said declutching jack;

a relay;

an electrical connection between said battery and said electrovalve, said connection comprising two de-clutching contactors in series activated by said ratio-changing member; said ratio-changing member opens one or the other of said contactors when one or the other of said gear ratios is interlocked, each of said contactors being mounted parallel respectively with the contactor of said relay, said relay including a coil energized by said output terminals of said electrical regulating contactor;

a single-action fuel-controlling jack activated by said fluid; said fuel-controlling jack piston rod is connected to said engine idler members;

an electrovalve interposed between said source and said fuel-controlling jack;

an electrical connection between said battery and said electrovalve, said connection comprises an idler contactor means for activation at the start of the de-clutching procedure by said member integral with said clutch control member.

4. A device as recited in claim 3, wherein said de-clutching contactors are combined into a single three-terminal declutching switch.

5. An automatic control device for a four-ratio mechanical gearbox of a motor vehicle, the gearbox comprises a ratiochanging member, the motor vehicle comprises a battery, a clutch having a control member, and an engine idler member,

said automatic control device comprises;

a source of fluid at a pressure difi'erent from atmospheric pressure;

a double-acting ratio-changing jack, activable by said fluid; said ratio-changing jack piston rod is connected to said ratio-changing member of said gearbox;

an electrical regulating contactor, propelled at a speed proportional to that of said vehicle, and comprising at least one first and one second output terminals, selectively supplied with current by said regulating contactor from said battery for a first and second range of velocity;

a first and second electrical connection, respectively interposed between said first output terminal and said first electrovalve and between said second output terminal and said second electrovalve, each ofsaid connections comprising two contactors in parallel, of which a first of said contactors is a self-maintaining contactor activated by said ratio-changing member, and of which a second of said contactors is a maneuver contactor, activated by said clutch; and said second contactor closes in the de-clutch position and further comprises a second ratio-changing jack, said second ratio-changing jack piston rod is connected to said ratio-changing member of said gearbox, said second jack activating said ratio-changing member in transverse direction if said firstmentioned ratio-changing jack activates said ratio-changing member in the longitudinal direction;

a de-clutching, single-action jack, activated by said fluid;

said de-clutching ratio-changing jack piston rod is connected to said control member of said clutch;

an electrovalve interposed between said source and said declutching jack; an electrical connection between said battery and said electrovalve, said connection comprising two de-clutching contactors in series, activated by said ratio-changing member; said de-clutching contactors open one or other of said contactors when one or other of said gear ratios is interlocked; a relay;

each of said contactors is mounted in parallel respectively with the contactor of said relay; said relay including a coil energized by one of said output terminals of said regulating contactor; a single-action fuel-controlling jack, activated by said fluid; said fuel-controlling jack piston rod is connected to said engine idler member;

an electrovalve interposed between said source and said fuel-controlling jack;

a member integral with said clutch member;

an electrical connection between said battery and said electrovalve, said connection comprises an idler contactor activated at the start of the de-clutching procedure by said member integral with said clutch control member.

6. A device as recited in claim 5, wherein said de-clutching contactors are combined into a single three-terminal de- -clutching switch.

7. A device as recited in claim 6, comprises a low-pressure tube; said source of fluid at a pressure different from atmospheric pressure is an air tank at a pressure lower than atmospheric pressure, connected to said low-pressure tube.

8. A device as claimed in claim 7, comprises a fluid connector rod, said ratio-changing jack comprises a pneumatic jack connected to said ratio-changing member by said fluid connecting rod and further comprises a master cylinder and a hydraulic receiver jack.

9. A device as recited in claim 8, comprising a hydraulic duct; a valve; both ends of said hydraulic receiver jack are interconnected by said hydraulic duct fitted with said valve.

Claims

1. In a motor vehicle having a change speed gear provided with a gear-shift member, a friction clutch, a gas throttle member, and a source of electric current, an automatic gear-changing system comprising: a vehicle speed responsive governor connected to said source and having at least two output terminals corresponding each to one of different speed ratios, respectively; first electromagnetically controlled means operative, when the electromagnet of said first means is energized, to move said clutch from the engaged position into disengaged position; second electromagnetically controlled means operative, when the electromagnet of said second means is energized, to move said throttle member into idling position; third electromagnetically controlled means operative, when the electromagnet of said third means is energized, to move said gear-shift member from its neutral position into one sPeed-engaging position corresponding to one of said different speed ratios; fourth electromagnetically controlled means operative, when the electromagnet of said fourth means is energized, to move said gear shift member from its neutral position into another speed-engaging position corresponding to another one of said different speed ratios; first circuit means comprising a first control switch for connecting the electromagnet of said first controlled means to said source; second circuit means comprising a second control switch for connecting the electromagnet of said second controlled means to a point of said first circuit means located between said first control switch and the electromagnet of said first controlled means; third circuit means comprising a control switch and a first holding switch for connecting the electromagnet of said third controlled means to one of said governor output terminals; fourth circuit means comprising a fourth control switch and a second holding switch for connecting the electromagnet of said fourth controlled means to another one of said governor output terminals; first switch-actuating means movable in unison with the axial movements of said clutch, said first switch-actuating means being connected to said second, said third, and said fourth control switches so as to close the same when said clutch reaches said disengaged position thereof; and second switch-actuating means movable in unison with said gearshift member and connected to said first control switch, and to said first and second holding switches so as to open said first control switch and to close said first and said second holding switches when said gear-shift member reaches any of said speedengaging positions thereof.

2. A motor vehicle as recited in claim 1, in which said vehicle speed-responsive governor has four output terminals two of which correspond to said one and said other speed ratios and two other of which correspond to two additional different speed ratios, and in which said automatic gear-changing system further comprises fifth electromagnetically controlled means operative, when said electromagnet of said fifth means is energized, to move said gear-shift member from said neutral position thereof to a second neutral position from which said gear-shift member is movable into a speed-engaging position corresponding to one of said two additional speed ratios or into another speed-engaging position corresponding to the other of said two additional speed ratios; fifth circuit means comprising a fifth control switch for connecting said third circuit means comprising said third control switch and said first holding switch to said fifth circuit means; a first relay connected to a first one of said two additional governor output terminals and adapted, when energized through said first output terminal, to connect said fifth circuit means and the electromagnet of said fifth controlled means to said first output terminal, sixth circuit means including a sixth control switch for connecting said fourth circuit means comprising said fourth control switch and said second holding switch to said sixth circuit means; a second relay connected to a second one of said two additional governor output terminals and adapted, when energized through said second output terminal, to connect said fifth circuit means and the electromagnet of said fifth controlled means to said second output terminal, and third switch-actuating means movable in unison with said gear-shift member between said neutral positions thereof and connected to said fifth and said sixth control switches so as to close the same when said gear-shift member reaches said second neutral position thereof.

3. An automatic control device for the mechanical gearbox of a motor vehicle, the gearbox comprises a ratio-changing member, the motor vehicle comprises a battery, clutch having a control member, and an engine idler member, said automatic control device comprises; a source of fluid at a pressure different from atmospheRic pressure; a double acting ratio-changing jack activated by said fluid; said ratio-changing jack piston rod is connected to said ratio-changing member; first and second electrovalves interposed between said source and, respectively, both ends of said ratio-changing jack cylinder; an electrical regulating contactor, propelled at a speed proportionate to that of the vehicle and comprising at least first and second output terminals selectively supplied with current by said regulating contactor from said battery, for a first and second range of velocity; a first and second electrical connection respectively interposed between said first output terminal and first electrovalve, and between said second output terminal and said electrovalve; each of said connectors comprises two contactors in parallel, one of said contactors is a self-maintaining contactor activated by said ratio-changing member, said second contactor is maneuver contactor activated by the clutch, said maneuver contactor closes in the de-clutch position; a de-clutching single-action jack, activated by said fluid; said de-clutching jack piston rod is connected to said control member of said clutch; an electrovalve interposed between said source and said de-clutching jack; a relay; an electrical connection between said battery and said electrovalve, said connection comprising two de-clutching contactors in series activated by said ratio-changing member; said ratio-changing member opens one or the other of said contactors when one or the other of said gear ratios is interlocked, each of said contactors being mounted parallel respectively with the contactor of said relay, said relay including a coil energized by said output terminals of said electrical regulating contactor; a single-action fuel-controlling jack activated by said fluid; said fuel-controlling jack piston rod is connected to said engine idler members; an electrovalve interposed between said source and said fuel-controlling jack; an electrical connection between said battery and said electrovalve, said connection comprises an idler contactor means for activation at the start of the de-clutching procedure by said member integral with said clutch control member.

4. A device as recited in claim 3, wherein said de-clutching contactors are combined into a single three-terminal de-clutching switch.

5. An automatic control device for a four-ratio mechanical gearbox of a motor vehicle, the gearbox comprises a ratio-changing member, the motor vehicle comprises a battery, a clutch having a control member, and an engine idler member, said automatic control device comprises; a source of fluid at a pressure different from atmospheric pressure; a double-acting ratio-changing jack, activable by said fluid; said ratio-changing jack piston rod is connected to said ratio-changing member of said gearbox; first and second electrovalves interposed between said source and, respectively, both ends of said ratio-changing jack cylinder; an electrical regulating contactor, propelled at a speed proportional to that of said vehicle, and comprising at least one first and one second output terminals, selectively supplied with current by said regulating contactor from said battery for a first and second range of velocity; a first and second electrical connection, respectively interposed between said first output terminal and said first electrovalve and between said second output terminal and said second electrovalve, each of said connections comprising two contactors in parallel, of which a first of said contactors is a self-maintaining contactor activated by said ratio-changing member, and of which a second of said contactors is a maneuver contactor, activated by said clutch; and said second contactor closes in the de-clutch position and further comprises a second ratio-changing jack, said second ratio-changing jack piston rod is connected to said ratio-changing member of said gearbox, said sEcond jack activating said ratio-changing member in transverse direction if said first-mentioned ratio-changing jack activates said ratio-changing member in the longitudinal direction; a de-clutching, single-action jack, activated by said fluid; said de-clutching ratio-changing jack piston rod is connected to said control member of said clutch; an electrovalve interposed between said source and said de-clutching jack; an electrical connection between said battery and said electrovalve, said connection comprising two de-clutching contactors in series, activated by said ratio-changing member; said de-clutching contactors open one or other of said contactors when one or other of said gear ratios is interlocked; a relay; each of said contactors is mounted in parallel respectively with the contactor of said relay; said relay including a coil energized by one of said output terminals of said regulating contactor; a single-action fuel-controlling jack, activated by said fluid; said fuel-controlling jack piston rod is connected to said engine idler member; an electrovalve interposed between said source and said fuel-controlling jack; a member integral with said clutch member; an electrical connection between said battery and said electrovalve, said connection comprises an idler contactor activated at the start of the de-clutching procedure by said member integral with said clutch control member.

6. A device as recited in claim 5, wherein said de-clutching contactors are combined into a single three-terminal de-clutching switch.