Centralized Electric Control Device in Particular for Automobile Vehicle Latches

The present invention relates to a centralized electric control device for a group of reversible motor-driven actuating devices, in particular for automobile vehicle latches.

A reversible motor-driven actuating device is a device of the type which may be driven, either by its motor supplied with current from a dc supply, or mechanically, and which, when it is made to move mechanically, is the centre of an electromotive force the sign of which is a characteristic of the direction of movement of the actuating device. Such devices may consequently be employed for actuating mechanically or electrically latch locking levers of in particular automobile vehicles.

An object of the present invention is to provide an electric control device controlling a group of actuating devices of the aforementioned type which, in response to the movement of one thereof in one direction or the other, commands all of the actuating devices to effect a movement in the same direction as the device which had been moved mechanically.

Consequently, the invention provides an electric control device controlling a group of at least two actuating devices of the aforementioned type, which comprises a circuit for detecting the presence and the polarity of an electromotive force at the terminals of at least one of said motors, a first power circuit which, in response to the detection by the detection circuit of an electromotive force of a given polarity at the terminals of said motor, connects all of the motors to said supply source in accordance with said given polarity, and a second power circuit which, in response to the detection by the detection circuit of an electromotive force of opposite polarity at the terminals of said motor, connects all of said motors to the supply source in accordance with the opposite polarity.

According to a feature of the invention, said circuit comprises first and second delay circuits which are triggered in response to the detection of an electromotive force of said given polarity and of the opposite polarity respectively and respectively actuating said first and second power circuits during a period at least equal to that required by said actuating devices to pass from one to the other of their positions.

According to another feature of the invention, the device comprises a third delay circuit which is triggered in response to the detection of an electromotive force of one or other polarity for inhibiting the detection circuit during a period of time at least equal to that required for ensuring that the current in said motors is eliminated after the cutting off of their supply by one of said power circuits.

According to yet another feature of the invention, said detection circuit comprises a first and a second amplifier which are responsive to the signs of the voltage applied to their control electrode and are connected to the respective terminals of said motor, and a multivibrator circuit whose inputs are connected to the outputs of said amplifiers and of the third delay circuit.

Further features and advantages of the invention will be apparent from the ensuing description of one embodiment thereof illustrated by the accompanying drawings, in which:

FIG. 1 is a longitudinal diagrammatic sectional view of a reversible motor-driven actuating device associated with a latch mechanism;

FIG. 2 is a block diagram of an electric control device according to the invention;

FIG. 3 is an electric circuit diagram of a specific embodiment of the control device according to the invention, and,

FIGS. 4a to 4h constitute a chronogram showing the shape of the voltage at different points of the circuit of FIG. 3.

Reference will be made first of all to FIG. 1 which shows an embodiment of a reversible motor-driven actuating device which may be employed with the control device according to the invention. This actuating device comprises a case 1 in which is disposed a dc electric motor 2 whose shaft 3 carries a gear wheel 4 which engages a gear wheel 5 connected to rotate with a reversible screw 6 which is rotatively mounted in the case 1. The screw 6 carries a carriage 7 having a part 8 forming a nut screwthreadedly engaged with the screw 6 and two arms 9 which extend out of the case through slots formed in the latter. The carriage 7 is connected by suitable mechanical connecting means to a latch mechanism 10 having a bolt 11 and a manual actuating member 12, shown in the form of a ring in the drawing but which may be formed by any suitable means such as a key or window frame pull-member etc . . . . The dc motor 2 is a reversible motor so that it can rotate in one direction or the other, depending on whether a voltage of a given polarity or of the opposite polarity is applied thereto. Depending on the direction of rotation imparted thereto by the motor 2, the screw 6 drives the carriage 7 in translation in one direction or the other so as to lock or unlock the latch 10. Likewise, the mechanical locking and unlocking operations of the latch 10 effected by the member 12 cause the carriage 7 to move in opposite directions. When it is thus driven by this mechanical operation of the latch 10, the nut 7 rotates the screw 6 and consequently the rotor of the motor 2. The latter is then the centre of an electromotive force whose polarity is a characteristic of the direction of displacement of the carriage 7.

It must of course by understood that the reversible motor-driven actuating device described hereinbefore is given merely by way of an illustrative example and it may be constructed in many other ways. In particular, the screw-nut system may be replaced by a rack and pinion system. Further, it will be observed that such a device may be employed for actuating any means which is movable between two positions, even if a preferred application of the invention resides in the control of automobile vehicle latches.

Reference will now be made to the block diagram of FIG. 2 which illustrates the control device according to the invention. This control device comprises a detection circuit for detecting the presence and the polarity of an electromotive force at the terminals of a group of motors M of reversible devices of the type defined in the preamble of the present description. This detection circuit comprises amplifiers A.sub.1 and A.sub.2 whose input is responsive to the polarity of the voltage applied thereto. The outputs of the amplifiers are applied to the inputs of a multivibrator circuit B whose two outputs are connected respectively to first and second delay circuits. The first delay circuit T.sub.1 pilots a first power circuit comprising an amplifier A.sub.3 and a relay R.sub.1 whereas the second delay circuit T.sub.2 pilots a second power circuit comprising an amplifier A.sub.4 and a relay R.sub.2. The relays R.sub.1 and R.sub.2 control a supply circuit S of the group of motors M in such manner as to supply power to the latter with a polarity which is identical to that which had been detected by the detection circuit. The control circuit is completed by a third delay circuit T.sub.3 controlled by the delay circuits T.sub.1 and T.sub.2 so as to inhibit the detection circuit by means of inhibiting elements IN.sub.1 and IN.sub.2.

The circuit described hereinbefore operates in the following manner:

The electromotive force produced by one of the motors of the group M in response to the mechanical actuation of one of the corresponding actuating devices is amplified in accordance with its direction by one or the other of the amplifiers A.sub.1 and A.sub.2. Beyond a threshold, the output signal of one of these two amplifiers actuates the multivibrator circuit B which triggers one or the other of the delay circuits T.sub.1 and T.sub.2, depending on the polarity of the detected electromotive force. The triggered delay pilots the associated amplifier and relay which control the supply circuit S so as to apply to the group of motors M a voltage of the same polarity as that of the detected electromotive force. Further, in response to the detection of this electromotive force, one or the other of the delay circuits T.sub.1 and T.sub.2 controls the third delay circuit T.sub.3 which acts on the input of the multivibrator circuit B so as to inhibit the latter for a period of time which is at least equal to that required to ensure that the current in the motors M is eliminated after the cutting off of their supply by one or the other of the relays R.sub.1 and R.sub.2. This inhibition of the multivibrator circuit is necessary upon the cutting off of the supply of the motors which occurs when that one of the delay circuits T.sub.1 and T.sub.2 which had been triggered returns to rest. Indeed, there then appears a self-induction electromotive force of a sign opposite to the voltage just cut off the effect of which would be, in the absence of the inhibition of the multivibrator circuit, to trigger the other path of the multivibrator circuit.

Reference will now be made to FIG. 3 which shows a circuit which conforms to the block diagram of FIG. 2. In this embodiment, the group of motors M comprises a motor group MR.sub.1, MR.sub.2, MR.sub.3 and MR.sub.4, hereinafter termed "receiver" motors, and another group of two motors MP.sub.1 and MP.sub.2 hereinafter termed "pilot" motors. The "receiver" motors are the motors of reversible actuating devices which may be operated electrically or mechanically but which, in the latter case, must not cause the energization of the other motors of the two groups. On the other hand, the "pilot" motors are motors belonging to reversible actuating devices which, when they are operated mechanically, must cause the energization of all the other motors, whether they be "pilot" or "receiver" motors. The "pilot" motors MP.sub.1 and MP.sub.2 are connected in parallel to a conductor a by one of their terminals and to a conductor b by the other terminals. Likewise, the "receiver" motors MR.sub.1, MR.sub.2, MR.sub.3 and MR.sub.4 are connected in parallel between conductors c and d.

The conductor a is connected to the base of a transistor TR.sub.1 corresponding to the amplifier A.sub.1 through a resistor R.sub.b1. The output of the transistor TR.sub.1, taken between its collector and its load resistor R.sub.c1, is applied to one of the two inputs of a NAND gate P.sub.1 whose output is connected to one of the two inputs of another NAND gate P.sub.2 whose output is connected to an inverter P.sub.3 through a capacitor C.sub.1 and a resistor Z.sub.1 connected between ground and the connection between the capacitor C.sub.1 and the inverter P.sub.3.

Likewise, the conductor b is connected to the base of a transistor TR.sub.2 corresponding to the amplifier A.sub.2 through a resistor R.sub.b2. The transistor TR.sub.2 also has a load resistor R.sub.c2 and its emitter, as the emitter of the transistor TR.sub.1, is connected through a conductor 13 to the positive terminal of a dc supply source (not shown) whose negative terminal is connected to a conductor 14. The output of the transistor TR.sub.2 is connected to one of the two inputs of a NAND gate P.sub.4 whose output is connected to one of the two inputs of a NAND gate P.sub.5. The output of the gate P.sub.5 is connected to an inverter P.sub.6 through a capacitor C.sub.2, and a resistor Z.sub.2 is connected between C.sub.2 and P.sub.6 on one hand and ground on the other.

The output of the gate P.sub.5 is connected to the other input of the gate P.sub.2 and the output of the gate P.sub.2 is connected to the other input of the gate P.sub.5 so that these two gates together form an RS multivibrator constituting the multivibrator circuit B of FIG. 2.

Further, the other inputs of the gates P.sub.1 and P.sub.2 are connected to the output of the delay circuit T.sub.3 so that these gates P.sub.1 and P.sub.2 constitute the elements which, depending on the state of the delay circuit T.sub.3, inhibit or enable the gates P.sub.2 and P.sub.5. The delay circuit T.sub.3 comprises a NAND gate P.sub.7 whose two inputs are respectively connected to the outputs of the inverters P.sub.3 and P.sub.6 and whose output is connected to the input of an inverter P.sub.8 through a resistor Z.sub.3 connected in parallel with a diode D.sub.1. The circuit T.sub.3 is completed by a capacitor C.sub.3 connected between ground and the connection between the resistor Z.sub.3 and the inverter P.sub.8 whose output constitutes the output of the delay circuit T.sub.3.

The output of the delay circuit or monostable T.sub.1, formed by the gate P.sub.3, the capacitor C.sub.1 and the resistor Z.sub.1, is applied to the base of a transistor TR.sub.3 constituting the amplifier A.sub.3 and whose collector is loaded by the energizing winding of the relay R.sub.1. Likewise, the output of the delay circuit or monostable T.sub.2, constituted by the gate P.sub.6, the capacitor C.sub.2 and the resistor Z.sub.2, is connected to the base of a transistor TR.sub.4 constituting the amplifier A.sub.4 and whose collector is loaded by the energizing winding of the relay R.sub.2.

The relay R.sub.1 controls four moving contacts, namely a contact r.sub.11 connected between the conductor b and the conductor 13, a moving contact r.sub.12 connected between the conductor a and the conductor 14, a moving contact r.sub.13 connected between the conductor d and the conductor 13 and a moving contact r.sub.14 connected between the conductor c and the conductor 14. In the same way, the relay R.sub.2 controls a moving contact r.sub.21 connected between the conductor a and the conductor 13, a contact r.sub.22 connected between the conductor a and the conductor 14, a moving contact r.sub.23 connected between the conductor c and the conductor 13 and a moving contact r.sub.24 connected between the conductor d and the conductor 14.

The circuit of FIG. 3 further comprises two diodes D.sub.2 and D.sub.3 of which one is connected between the conductor a and the conductor 13 and the other between the conductor b and the conductor 13. There are provided two manual control contacts CM.sub.1 and CM.sub.2, the first of which is connected between the conductor a and ground whereas the second is connected between the conductor b and ground so as to permit electrically controlling the group of motors without manual operation of one of the actuating devices having a "pilot" motor.

The operation of the circuit of FIG. 3 will be explained with reference also to FIGS. 4a to 4h. When one of the actuating devices associated with the pilot motors MP.sub.1 and MP.sub.2 is operated mechanically, the corresponding motor operates as a generator and develops an electromotive force V.sub.ab (FIG. 4a). At time t.sub.1, when this electromotive force has reached a sufficient threshold value, it renders conductive one or the other of the transistors TR.sub.1 and TR.sub.2, depending on its polarity. For reasons of simplicity, it will be assumed hereinafter that it is the transistor TR.sub.1 which has been rendered conductive, bearing in mind that the operation would be identical if it concerned transistor TR.sub.2.

At rest, before the conduction of transistor TR.sub.1, the transistors TR.sub.1 and TR.sub.2 are off and the inputs of gates P.sub.1 and P.sub.4 respectively connected to resistors Rc.sub.1 and Rc.sub.2 are at 0. The inputs of gates P.sub.1 and P.sub.4 connected to the output of inverter P.sub.8 are at 1.

The output of inverter P.sub.8 is at 1 since its input is at 0 for the following reason.

The outputs of inverters P.sub.3 and P.sub.6 are at 1 at the end of the delay introduced by the circuits T.sub.1 or T.sub.2 (FIG. 4d). The inputs of gate P.sub.7 are at 1 and its output and consequently the input of inverter P.sub.8 are at 0 after the discharge of the capacitor C.sub.3 through the resistor Z.sub.3.

The inputs of gates P.sub.1 and P.sub.4 being respectively at 0, 1, their outputs are both at 1.

Accordingly the corresponding inputs of gates P.sub.2 and P.sub.5 which form the multivibrator B are at 1.

It is assumed that before transistor TR.sub.1 is rendered at first conductive the state of multivibrator B at rest is such that the output of gate P.sub.2 is 0 and the output of gate P.sub.5 is 1. FIGS. 4d and 4c show that at time T.sub.2 the states of inverters P.sub.3 and P.sub.6 are both at 1. The input of inverter P.sub.3 is at 0 since the output of gate P.sub.2 is at 0 and capacitor C.sub.1 is discharged. The input of inverter P.sub.6 is also at 0 since capacitor C.sub.2 was previously charged through resistor Z.sub.2.

At conduction of transistor TR.sub.1, a current flows between the emitter and the base of the transistor TR.sub.1, the circuit of this transistor being closed through one of the diodes D.sub.2 and D.sub.3. A voltage appears at the terminals of the resistor R.sub.c1 (FIG. 4b) and this voltage is applied to the gate P.sub.1. When, at time t.sub.2, this voltage reaches a sufficient threshold value, the gate P.sub.1 is enabled owing to the fact that the delay circuit T.sub.3 is not triggered and the RS multivibrator circuit P.sub.2, P.sub.5 triggers the delay circuit T.sub.1 which produces at the output of the inverter P.sub.3 the rectangular pulse shown in FIG. 4d. This renders the transistor TR.sub.3 conductive and, after the voltage at the terminals of the energizing winding of the relay R.sub.1 has reached a sufficient value, at time t.sub.3, the relay R.sub.1 closes the moving contacts r.sub.11 and r.sub.12 which supplies current to the "pilot" motors MP.sub.1 and MP.sub.2 with the same polarity as that of the electromotive force which had initiated the procedure, and the moving contacts r.sub.13 and r.sub.14, which supplies current to the "receiver" motors MR.sub.1, MR.sub.2, MR.sub.3 and MR.sub.4 also with the same polarity.

At time t.sub.4, the delay circuit T.sub.1 returns to rest (FIG. 4d), which blocks the transistor TR.sub.3 so that the relay R.sub.1 is no longer energized and the supply to all the motors is cut off. There then occurs an inversion of polarity at the terminals of these motors which causes the conduction of transistor TR.sub.2 and the delivery of a control signal at one of the inputs of the gate P.sub.4 (FIG. 4c). However, the delay circuit T.sub.3, which had been triggered at time t.sub.2 by the delay circuit T.sub.1, has a time constant exceeding that of the delay circuits T.sub.1 and T.sub.2 so that the gate P.sub.4 is inhibited as long as a control voltage is applied by the transistor TR.sub.2 to the gate P.sub.4. The delay circuit T.sub.3 thereafter returns to its position of rest at time t.sub.5 (FIG. 4f) which is calculated in such manner that there is no longer any current in the "pilot" motors and the transistor TR.sub.2 is blocked. The cycle of operation of the control circuit has then terminated and the actuating devices have effected a complete travel.

If, subsequently, one of the devices associated with a "pilot" motor is actuated mechanically in the other direction, it is the other transistor TR.sub.2 which is rendered conductive and a new cycle of operation occurs as from time t.sub.6, as shown in FIGS. 4a to 4h. However, this operation will not be described in detail since it is merely the reverse of that which has just been described, the operation of the relay R.sub.2 being illustrated by FIG. 4h.

Note that without mechanical operation of the actuating devices associated with the "pilot" motors, it is possible to cause the rotation of the motors in one direction or the other by acting on one or the other of the manual contacts CM.sub.1 and CM.sub.2, the operation of the circuit being then identical to that just described.

The control device according to the invention has the advantage of requiring no detection by a position sensor in the region of the mechanicam of the actuating device, which considerably simplifies the system. Further, it limits the wiring between the control device and the actuating devices to merely the power conductors. Another advantage resides in the fact that the motors, which have a low impedance, are connected in parallel to the input of the circuit so that the latter is greatly immunized from parasites. The use of a logic system allows moreover the adoption of a CMOS technology having a low consumption of energy. The configuration of the circuit permits, by direct action on the multivibrator circuit, the use of any other control system such as the manual control contacts CM.sub.1 and CM.sub.2 or inertia switches for example.