MXPA97007358A - Inductive universal lever and signal processing circuit for the mi - Google Patents

Abstract

An inductive universal lever comprises a movable actuator (16) carrying an element (18) of electrically conductive material of low magnetic permeability (eg copper, or aluminum), so that the movement of the actuator differentially affects the coupling between a primary coil 810) and a pair of secondary coils (12, 14) that are encircled by the primary coil. The installation provides a desirable output characteristic, in which the minimum output of each secondary coil is preferably greater than the maximum difference between the outputs of the two secondary coils, useful for detecting the faults of the components. The secondary coils are preferably connected in a processing circuit that rectifies the outputs of the two coils before combining them to form an output resulting from the "difference".

Description

INDUCTIVE UNIVERSAL LEVER AND SIGNAL PROCESSING CIRCUIT FOR THE SAME Field of the Invention This invention relates to an inductive universal lever and a signal processing circuit for such an inductive lever. BACKGROUND OF THE INVENTION Inductive levers are known to control the apparatus in many different applications. One of such universal levers is shown in Figure 1 of the drawings and comprises an operating lever 16 having a primary induction coil 10 fixed to its lower end. A pair of fixed secondary coils 12, 14 are provided for each axis of the universal lever, the coils of each such pair being connected so that their outputs are in anti-phase. The primary coil 10 is provided with a variable input voltage sinusoidally through bending wires 11, which connect the supply (not shown) located in the fixed portion of the universal lever to the primary coil 10. In use, the lever 16 is pivoted around a pivot point 9 such that the primary coil 10 is displaced relative to the secondary coils 12, 14. When the operating lever 16 is in the center position, the magnetic coupling between the primary coil 10 and the secondary coils 12, 14 cause equal output voltages to be induced in the two secondary coils. Since these output voltages are connected in anti-phase, they are canceled and there is no output resulting from each pair of secondary coils. However, if the operating lever 16 is moved, whereby the primary coil 10 is displaced relative to the secondary coils 12, 14, the magnetic coupling between them is altered, and the output voltages of the two secondary coils already They are not the same. Therefore, there will be an output resulting from the pair of secondary coils on the axes along which the operating lever moves. This resulting output, which is dependent on the distance by which the primary coil 10 has moved from its central position in relation to the secondary coils 12, 14, is applied to a control system, which can therefore determine the relative position of the operating lever, for the appropriate control of the apparatus for which the universal lever is provided. A problem associated with the installation described above is that the bending wires 11 are subjected to the fatigue action in operation. In this way, over a period of time, the wires can weaken and break, causing faults in the universal lever.

Another known universal lever, which overcomes the above problem, is shown in Figure 2 and again comprises an operating lever 16, pivoted at 9, and a pair of fixed secondary coils 12, 14 for each axis of the universal lever, being connected the coils of each such so that their outputs are in anti-phase. However, in this case, the primary induction coil 10 is fixed in the center of the secondary coils, and all the coils are wound in a ferromagnetic core 13. A ferromagnetic disk 15 is fixed to the lower end of the operating lever 16 When the lever 16 is in its central position above the coil installation, the coupling between the primary coil 10 and the respective secondary coils 12, 14 causes equal output voltages to be induced in the secondary coils and the resultant output of each axis is zero, according to the above. However, the displacement of the operating lever 16 and therefore of the ferromagnetic disk 15 causes a change in the magnetic coupling between the primary coil 10 and the secondary coils 12, 14 of the axes in which the lever moves. This in turn causes the output voltages induced in those secondary coils to be unequal and therefore there is a resultant output from the secondary coils in those axes. This resulting output is applied again to a control system, by means of which the position of the lever 16 is determined and the apparatus for which the universal lever is provided is appropriately controlled. In the installation shown in Figure 2, the need for bending wires is eliminated since the primary coil is located in the fixed portion of the universal lever and can be connected directly to the input voltage. However, the resulting output voltage against the deflection characteristic of the operating lever is not linear. Therefore, it is difficult to obtain exact control of the apparatus. Another disadvantage of the installation described above is that the ferromagnetic material is expensive and the need for a large ferromagnetic core common to all the coils results in a relatively expensive installation. We have now invented a universal lever that overcomes the problems outlined above, which are associated with known universal levers. SUMMARY OF THE INVENTION According to the present invention, an inductive universal lever is provided, comprising a movable actuator, which is provided with an element of electrically conductive material of low magnetic permeability, a pair of secondary coils for the respective axes of deflection of said actuator, and a primary induction coil for inducing signals in said secondary coils, said primary induction coil being located to surround said secondary coils and installing said actuator so that its electrically conductive element is located within the magnetic field of the primary induction coil and deviate in relation to said secondary coils in motion of said actuator. When the electrically conductive element of the universal lever actuator is located within the magnetic field of the primary coil, electric currents (Eddy currents) are induced in that element. These currents in turn establish a magnetic field around the conductive element. When the actuator is placed in such a way that its conductive element is in a central position between the secondary coils, the magnetic field in the center of the conductive element is opposed to the magnetic field of the primary coil, and the magnetic field in the outer region of the conductive element reinforces the magnetic field of the primary coil. In this way, the magnetic coupling between the primary coil and the secondary coils induces equal voltages in each of the secondary coils. Secondary coils for the or each axis of the universal lever are preferably connected to means for forming a resultant signal according to the difference between the outputs of those coils. This resulting signal is indicative of the position of the actuator of the universal lever in relation to the two secondary coils. The outputs for each axis are preferably applied to a control system, which may be integral with, or external to, the universal lever. Therefore, when the actuator is in a central position, the output voltages from the secondary coils in each pair are canceled and there is no resultant output. However, if the actuator moves along an axis in such a way that its electrically conductive element is diverted to one of the secondary coils of a pair, the induced field resistance in that coil is reduced and its output voltage is reduced. therefore, it is also reduced. The field resistance induced in the other secondary coil of the pair increases according to the above, thus increasing its output voltage. In this case, therefore, a resultant signal is formed from the outputs of that pair of secondary coils, which is representative of the distance by which the operating lever has been diverted from its central position. When this resulting signal is applied to the control system, the latter can determine the position of the actuator, for proper control of the apparatus being controlled. A particular advantage of the universal lever defined above, due in particular to the use of the conductive element and the location of the primary coil to surround the secondary coils, is that a desirable response characttic can be achieved. In this way, the characttic can be achieved when, in operation of the universal lever, the minimum output of each secondary coil is significantly greater than the difference between the outputs of the respective pair of secondary coils. This allows certain failure modes of the universal lever to be detected, as will be described below. The electrically conductive element, which is preferably a disc and is preferably made of copper, aluminum or aluminum alloy, provides a reasonably greater change in the output voltage for a given deflection of the actuator, and the linearity characttic is provided of the resulting output signal / deflection of the actuator. In this way, the position of the actuator in relation to the secondary coils can be detected more accurately using the universal lever of the present invention: in addition, this universal lever costs significantly less than one that requires the coil to be wound on the ferromagnetic cores . Another advantage of the universal lever is that it does not require bending wires. In Figure 9 of the drawings, a known signal processing circuit for known universal levers is shown. The installation generally comprises a primary circuit 100 and two secondary circuits 102, 104. The primary circuit 100 comprises a primary induction coil 101, which is connected to a a.c. (alternating current) connected through an input voltage Vs. Each of the secondary circuits 102, 104 comprises two coils for example 106, 108 wound in anti-phase and connected in ss. The coils 106, 108 are connected to an analog switch 112. The output of each switch 112 is applied to the reversing input of an operational amplifier 122, connected respectively between the input voltage rail Vs and the ground (Ov). . A capacitor 124 and a resistor 126 are connected in parallel with each other between the inverting input of the operational amplifier 122 and its output. The non-inverting input of the amplifier 122 is held at a reference voltage Vs / 2 of half the input voltage Vs. A second capacitor 128 is provided through the two inputs of the amplifier 122 for EMI protection. (Electromagnetic interference).

The coils 106, 108 of each of the circuits 102, 104 are placed at 45 ° of the X and Y axes respectively of the universal lever. When the input voltage Vs is turned on, the resulting alternating current in the primary induction coil 101 induces anti-phase voltages in the secondary coils 106, 108, which combine to obtain voltages A and B. The voltages A and B they are synchronously rectified individually and then added, the ce (direct current) is averaged and amplified to obtain an output axis X, or they are differentiated, the ce (direct current) is averaged, and amplified to obtain an output of axis Y. In particular: output of the axis Y = K (A + B) output of the axis X = K (AB) where K is the circuit gain, A is the output voltage of the first secondary circuit 102, and B is the output voltage of the second secondary circuit 104. Under normal operating conditions, a deflection of the universal lever along the Y axes causes the output Y to change and the output X to remain constant. However, in the case of a failure of any of the secondary circuits, a deflection along the Y axis causes a change in both the output of the Y axis and the X axis: failure of the secondary circuit 102: X = K (0 -B) = -KB secondary circuit fault 104: X = K (A-0) = KA Similarly, a deflection along the X axis under fault conditions causes a change in the output of the Y axis. , since both outputs are within the operating range of the circuit, the failure continues without being recognized. Referring to Figure 10, in an alternative installation of the prior art, the secondary coils are placed on the X axis and the Y axis of the universal lever. In some applications, the Y axis is used to control the forward / reverse speed of a vehicle, while the X axis is used to control the position of the steering. A failure in the X-axis circuit 102 could not affect the Y-axis circuit 104, so the user could select any desired forward / reverse speed at the usual maximum speed, without steering facilities. This is clearly a dangerous situation. We have now invented an electronic circuit that overcomes the problems outlined above, which are associated with known signal processing circuits for universal levers. Thus, in accordance with the present invention, an electronic circuit is provided for a universal inductive lever, comprising a primary induction coil and at least one secondary circuit, the or each of said secondary circuits comprises the first and second coils , the outlets of which are connected through respective rectifying means to combination means to provide a resultant signal according to the difference between the outputs of said first and second coils and representing the deflection of a universal lever actuator . Because the two secondary coil outputs are rectified before they combine to form their signal resulting from the "difference", then in case of failure of any of the components in the, or in each secondary circuit, a resultant output is produced that exceeds normal operating limits. Through the output a separate safety mechanism can be operated and the actuator can be alerted. This contrasts with the installations of the prior art, in which the coil outputs are combined before the rectification, since in these installations faults can occur without the resultant exceeding its normal range. The rectification means may comprise synchronous or homodyne devices such as analogous switches. However, preferably, in order to minimize the number of components and thus improve the reliability and reduce the cost of the circuit, the rectifying means comprise a rectifier diode installation. Preferably, each secondary circuit comprises a pair of diodes, one for each of the first and second coils, formed on the same semiconductor substrate. Diode rectifiers are inherently non-linear at low input signal amplitudes, mainly due to their forward voltage values. An additional advantage of the rectification of the outputs of the secondary coil, prior to the combination of these outputs to form the resulting signal, is that the input signals for the rectifier diodes are large compared to their forward voltage drops: otherwise, if the resulting signal were formed prior to rectification, the resulting signal would be relatively small and its characteristic would therefore be more affected by the forward voltage supply of the diode. The coils of each secondary circuit can be placed respectively on the X and Y axes of the universal lever. They can be placed alternatively at 45 ° of them. The circuit is preferably installed so that the output under fault conditions is at least 1.2 times the normal maximum, and more preferably at least 1.5 times the normal maximum.

BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the present invention will now be described only by way of examples and with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of an inductive universal lever of the prior art; Figure 2 is a schematic side view of another inductive universal lever of the prior art; Figure 3 is a schematic side view of an inductive universal lever according to the present invention; Figure 4 is a schematic plan view of the universal lever of Figure 3; Figure 5 is a view of the universal lever of Figure 3 when the operating lever is deflected in one direction; Figure 6 is a graphic representation of the output of the secondary coil when the operating lever is in the position shown in Figure 5. Figure 7 is a view of the universal lever of Figure 3 when the operating lever is it deviates in the opposite direction. Fig. 8 is a graphic representation of the output of the secondary coil when the operation lever is in the position shown in Fig. 7; Figure 9 is a diagram of an electronic signal processing circuit of the prior art for an inductive universal lever. Figure 10 is a diagram of an alternative signal processing circuit of the prior art for an inductive universal lever. Figure 11 is a diagram of a first embodiment of the electronic circuit according to the present invention; Figure 12 is a diagram of a second embodiment of the electronic circuit according to the present invention; Figure 13 is a diagram of a third embodiment of the electronic circuit according to the present invention; Fig. 14 is a diagram of a fourth embodiment of the electronic circuit according to the present invention; Figure 15 is a diagram of one of the secondary circuits of Figure 11 having an alternative construction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figure 3 of the drawings, an inductive universal lever according to the present invention comprises a generally annular, outer primary induction coil 10, and a pair of secondary coils 12, 14 for each axis of the universal lever, the secondary coils being surrounded by the primary coil 10. In the case where the universal lever is for controlling an apparatus through two axes, an X axis and a Y axis, two pairs of secondary coils 12 are necessary, 14, as shown in Figure 4. The secondary coils 12, 14 for each axis, are connected in such a way that their outputs are in anti-phase. All coils 10, 12, 14 are fixed and the primary induction coil is connected to an input voltage (not shown), which can be placed in any convenient position. Referring again to Figure 3, the universal lever further comprises an operation lever 16, having a disc 18 of electrically conductive material of low magnetic permeability, for example, copper, fixed at its lower end. The lever 16 is mounted pivotally at a point 9 generally in a central position above the secondary coils 12, 14. When the voltage input to the primary induction coil is turned on, then, if the electrically conductive disk 18 were absent, the magnetic coupling between the primary coil 10 and the secondary coils 12, 14 would cause equal voltages to be induced in those secondary coils. With the conductive disk 18 inserted into the magnetic field of the primary coil 10, the electric currents are induced within the disk. These currents establish a magnetic field around the conductive disk 18. The magnetic field in the center of the disk opposes the magnetic field of the primary coil, while the magnetic field in the outer region of the disk reinforces the magnetic field of the primary coil. In this way, when the operating lever 16 is in its central position, respectively the magnetic field in and around the electrically conductive disc 18, has an opposite effect on the magnetic field of the primary coil, the voltages induced in the secondary coils are equal and , since the secondary coils 12, 14 of each pair are connected in such a way that their outputs are in anti-phase, cancel each other in such a way that there is no resultant output signal. Referring to Figure 5 of the drawings, in use, if the operating lever 16 is moved by means of an operator to deflect the electrically conductive disk 18 towards one of the secondary coils 12 of a pair, the field resistance induced in that coil 12 is reduced due to the opposing effect of the magnetic field at the center of the electrically conductive disk 18, and the voltage induced in the coil 12 is reduced according to the above. Similarly, the field resistance and consequently the voltage induced in the opposite coil 14 is increased, due to the strengthening effect of the magnetic field in the outer region of the electrically conductive disk 18. The outputs of the coils 12, 14 are shown in graphical form in figure 6. Curve 22 represents the output voltage of each coil when the operating lever is in central position, and curves 24 and 26 respectively represent the output voltages of coils 12 and 14 when the operating lever are in the position shown in figure 5. As the outputs of the coils are no longer equal, there is a resulting output signal, which is representative of the distance by which the lever 16 has been diverted as far as possible. length of the respective axis. Referring to Figure 7 of the drawings, if the operating lever 16 is biased towards the secondary coil 14, the field resistance and consequently the induced voltage in that secondary coil is reduced, while the field strength and consequently the induced voltage in the opposite secondary coil 12 is increased. This can be seen more clearly in Figure 8, in which the curve 22 again represents the output voltages of each coil 12, 14 when the operating lever 16 is in the central position, and the curves 24 and 26 respectively represent the output voltages of the coils 12 and 14 when the operating lever 16 is in the position shown in figure 7. The installation described above provides the characteristic that the minimum output (A) of the coil 12 in deflection The maximum operating lever 16, as shown in figures 5 or 7, is greater than the maximum difference (B) between the outputs of the two coils: this ensures that certain failure modes of the universal lever can be detected. It has been found convenient to design the installation in such a way that A >; 1.5B. The resulting output signal is applied to a control system, which determines the position of the operating lever and in accordance with the above controls the apparatus for which the universal lever is provided. Referring to Figure 11 of the drawings, there is shown an electronic signal processing circuit, which can be used with the universal lever described above with reference to Figures 3 to 8, and which comprises a primary circuit 30 and two identical secondary circuits. , 34. The primary circuit 30 comprises a primary induction coil 10, which is driven by means of an AC generator. (alternating current) connected through an input voltage Vs. Each of the secondary circuits 32, 34 comprises two coils 12, 14, which are wound in such a way that their output voltages are in anti-phase to reduce the voltage fluctuation in the output. The coils 12, 14 are connected through the inlets of a silicon microcircuit 40, comprising two opposite diodes 42, 44 formed on the same silicon substrate. By using diodes, which are part of the same silicon microcircuit, it is possible to ensure that the forward voltage flow and the temperature coefficient are equal for the two diodes. This also ensures that both diodes are at the same temperature. The outputs of the two diodes 42, 44 are combined, through the resistors 46, 48, so as to form a summing junction 50. The output of the summation junction is applied to the inverted input of an operational amplifier 52 , connected between the voltage input rail Vs and the ground connection. A capacitor 54 (to average or filter the ce) and a resistor 56 are connected in parallel with each other between the inverting input of the operational amplifier 52 and its output. The non-inverting input of amplifier 52 is held at a reference voltage Vs / 2 of half the input voltage Vs. A second capacitor 38 is provided through two inputs of the amplifier 52 for EMI protection. The coils 12, 14 of each of the secondary circuits 32, 34 are respectively placed on the X axis and the Y axis of the universal lever. The operation of the secondary circuits 32, 34 will now be described with reference only to the first secondary circuit 32, but is equally applied to the second secondary circuit 34. When the input voltage Vs is turned on, the resulting alternate current in the coil of primary induction 10, induces an alternative voltage in each of the secondary coils 12, 14. If the coils 12, 14 are identical, the alternative voltages induced in the two coils, which are in phases opposite but centered around the half of the input voltage Vs / 2, are equal when the universal lever is in its central position along the X axis. During the positive half cycle of the output voltage of the coil 12, the first diode 42 is conducted to give a current having an average of ce of ix: during the negative half-cycles of the output voltage of coil 14, the second diode 44 is conducted to give a current having an average of ece of i2. In this way, the currents coming from each of the coils 12, 14 enter the summing junction 50 in anti-phase. With the universal lever in central position, the magnitudes of ii and i2 are equal and will therefore cancel each other at the summing junction 50. Under these circumstances, no current flows from the summing junction to the reversal output of the operational amplifier 52, and therefore there is no resultant output signal. When the universal lever is deviated along the X axis, there is an imbalance between the currents ii and i2 flowing in the secondary circuit 32 and a resulting current having an average of ce of i, flows from the sum junction. 50. For example, if you deviate the universal lever on the X axis in a positive direction, an imbalance is created between the currents ii and i2 in the secondary circuit 32 and in the current i, whose magnitude is equal to the difference between the magnitudes of ii and i2, which flows from the sum junction 50 to the input of inverter of the operational amplifier 52 of that circuit 32. In this way, the output voltage of the X axis of the secondary circuit 32 under normal operating conditions, can be expressed as: Vout ai where i = (i? - i2) A controller suitable external (not shown) detects the outputs of the operational amplifier 52 for each axis and responds according to the foregoing. The maximum value of i, in the secondary circuit 32 or 34, occurs when the universal lever is respectively at its maximum deflection along the X or Y axis. In this way, under normal operating conditions, the output of the circuits secondary 32, 34 will never exceed a maximum Vout, which is proportional to the maximum of i, that is: 0 = i = maximum of i Secondary circuits 12, 14 are installed in such a way that: ii >; maximum of i, i2 > maximum of i in each case. Accordingly, in the event that an open circuit fault, for example, coil 12, diode 42 or resistor 46, ix is zero and i = i2. The output voltage from an operational amplifier 52 is then proportional to i2, which is detected by the controller as being outside the range of normal operating conditions. In the case of a failure of a short circuit, for example, diode 42, the total waveform of ca is passed. The cd average of the ac waveform is zero and therefore ii is zero. In this way, i = i2 and the output voltage of the operational amplifier 52 is again proportional to i2, which results in a resultant output signal, which is outside the normal operating limits. The circuits 32, 34 can be designed so that: ii = 1.5 of the maximum of i, and i2 = 1.5 of the maximum of i, respectively. Referring to Figure 12 of the drawings, in a modified circuit, the diodes 42 44 are connected in parallel respectively through their associated coils 16, 18, and the capacitors 60, 62 are connected in series with each coil 12, 14 for forming a voltage duplicator and respective rectification circuits. Referring to Fig. 13 of the drawings, in another embodiment, the circuit of such marera is installed so that each of the secondary coils is at 45 ° of the X and Y axes of the inductive universal lever (similar to the circuit of the figure 9). The circuit 32 has a second summing connection 51 and both of its summing connections provide the outputs A: similarly the circuit 34 has a second summing union formed by a second set of diodes and resistors, the two summing connections provide respectively outputs B and -B. The outputs of the respective summing junctions of the two circuits 32, 34 combine to produce an output Y K (A + B) and an output X K (A-B). Referring to Figure 14 of the drawings, for example, diodes 42, 44 in secondary circuits 32, 34, of Figures 11, 12, and 13 can be replaced by any other suitable rectifying component, eg, analog switches 64, 66, operated synchronously with the drive signal for the primary coil. It will be appreciated that the positions of certain components within the electronic circuit according to the present invention can be exchanged. In this way, for example as shown in FIG. 15 only for the secondary circuit 32, the positions of the diodes 42, 44 can be exchanged, respectively, with those of the resistors 46, 48. This is advantageous in many circumstances since the board on which the circuit can be mounted, displays inherent capacitance connections, which can form RC filters with the resistors 46, 48 and thus eliminate the high frequency signals of the coil signals, before rectification.

Claims (11)

1. NOVELTY OF THE INVENTION Having described the present invention is considered as a novelty and therefore claimed as property described in the following claims 1. An inductive universal lever, comprising a movable actuator, which is provided with an element of material electrically conductive of low magnetic permeability, a pair of secondary coils for respective deflection axes of said actuator, and a primary induction coil for inducing the signals in said secondary coils, said primary induction coil being placed to round said secondary coils and placing said actuator so that said electrically conductive element is placed within the magnetic field of the primary induction coil and deviates in relation to said coils secondary to the movement of said actuator.
2. 2. An inductive universal lever according to claim 1, characterized in that said electrically conductive element comprises copper, aluminum or aluminum alloy.
3. 3. An inductive universal lever according to claim 1 or 2, characterized in that said electrically conductive element is in the shape of a disc.
4. 4. An inductive universal lever according to any of the preceding claims, characterized in that said actuator is pivoted about a point on the axes of said primary induction coil. An inductive universal lever according to any of the preceding claims, characterized in that it comprises means connected to each of said pair of secondary coils, to form a resultant signal according to the difference between the outputs of those coils. 6. An inductive universal lever according to claim 5, characterized in that it is installed in such a way that the minimum output of each of said secondary coils is greater than the maximum difference between the outputs of the pair of secondary coils. 7. An inductive universal lever according to claim 6, characterized in that it is installed in such a way that the minimum output of each of said secondary coils is at least 1.5 times the maximum difference between the outputs of the pair of secondary coils. 8. An electronic circuit for an inductive universal lever, comprising a primary induction coil and at least one secondary circuit, the one or each of said secondary circuits comprising first and second coils, the outputs of which are connected through of respective rectifying means to combination means for providing a resultant signal according to the difference between the outputs of said first and second coils and representing the deflection of a universal lever actuator. 9. An electronic circuit according to claim 8, characterized in that the respective rectifying means are connected in series on respective circuits from the first and second coils to said combination means. 10. An electronic circuit according to claim 8, characterized in that the respective rectifying means are connected in shunt on respective circuits from the first and second coils to said combination means. 11. An electronic circuit according to any of claims 8 to 10, characterized in that the respective rectifying means comprise diodes. 12 An electronic circuit according to claim 11, characterized in that said diodes are formed on a common semiconductor substrate. An electronic circuit according to any of claims 8 to 10, characterized in that the respective rectifying means comprise analogous switches. An electronic circuit according to any of claims 8 to 10, characterized in that it comprises two of said secondary circuits, the two coils of the respective secondary circuits being placed on orthogonal axes X and Y in such a way that the outputs resulting from the respective secondary circuits represent the deflection of said actuator of the universal lever along said axes X and Y respectively. 1
5. 5. An electronic circuit according to any of claims 8 to 13, characterized in that it comprises two of said secondary circuits, the two coils of the respective secondary circuits being placed on the axes placed at 45 ° of the orthogonal axes X and Y, and means for combining the outputs resulting from the respective secondary circuits to provide signals which represent the deflection of said actuator of the universal lever along said X and Y axes respectively. 1
6. 6. An inductive universal lever according to any of claims 1 to 7, characterized in that it is provided with an electronic circuit according to any of claims 8 to 15.