Abstract: A tachometric device is provided with a D.C. electric motor a shaft of which drives a pair of permanent magnets to rotate. A first permanent magnet controls a speed indicator unit; a second permanent magnet is rotatably mounted within a winding the terminals of which are connected to a negative feed back circuit for controlling the speed of the motor.

Abstract: A speed indicator device for vehicles is described, of the type in which the speed indication is given over a scale by an index fitted to an oscillating element drawn for example, by a permanent magnet carried into rotation by the shaft of an electric motor. The device comprises a bush on one side fixed to the magnet and on the other fixed, by a spring, to the shaft of the electric motor.

Abstract: A vehicle fuel level sensor comprising a hollow cylindrical body housing a sliding float, the position of which is determined by the fuel level in the fuel tank. The sensor also comprises a filter surrounding as portion of the side wall of the cylindrical body, close to the bottom wall of the same, so as to define, with the side wall, a first chamber; and a plate for supporting the filter and connected to the bottom wall of the hollow cylindrical body so as to define, with the bottom wall, a second chamber communicating directly with the first chamber and, via a through hole in the bottom wall, with the inside of the hollow cylindrical body.

Abstract: A tachometric generator comprises an input shaft which can be connected to a drive take-off from the vehicle, a main shaft connected to this input shaft by means of a ball joint resilient coupling torsionally coupled to an output shaft which can be connected to an external mechanical transmission. The speed of rotation of these shafts is detected by a magneto-electric sensor facing a magnetic disc fitted onto the output shaft.

Abstract: An electronic interface device is provided for use between a sensor and a display unit, including a controllable generator which delivers a signal to the display unit and is connected to an input of a comparator whose other input receives the output signal of the sensor. The output of the comparator controls the up counting or the down counting of an up-down counter of clock pulses. The sign output of the up-down counter controls the generator.

Abstract: The device is of the type comprising a magnet carried by a float and a magnetically actuable electric contact carried by a support element which also performs the function of guarding the float. The most important characteristic of the device is that of providing positioning means which maintain the float constantly centered with respect to the support element during excursions of this latter caused by the hydrostatic thrust exerted by the liquid.

Abstract: A method is provided for displaying the speed and the distance on board a motor vehicle. The shaft of an auxiliary motor drives a speed indicator and a mileage recorder and its rotation controls a train of pulses. The speed of rotation of the auxiliary motor is controlled so that the period of the train of pulses and the total number of pulses are slaved respectively to the period of another train of pulses and to their total number, this other train of pulses being controlled by the rotation of one of the wheels of the vehicle.

Abstract: A probe for measuring the level of a liquid and its method of manufacture are disclosed. A conducting circuit whose resistivity depends on temperature comprises a track applied to a substrate in which is formed a window which leaves free an appreciable length of track, so that its behavior is not disturbed by the presence of the substrate. The conducting circuit is partially immersed in the liquid and the voltage at its terminals is measured when a constant current flows therethrough. The voltage measurement is representative of the level of the liquid.

Abstract: An on board indicator for vehicles is provided, including a sensor detecting a physical magnitude to be indicated, connected to a display device through a low pass filter whose cut off frequency is increased for a given time after switch on of the vehicle, by appropriate circuitry. A threshold detector controlling an alarm device is connected to the output of the low pass filter. Such an indicator may be used for indicating the fuel level in the reservoir of a motor vehicle, for example.

Abstract: A liquid crystal display device is provided comprising a liquid crystal wafer operating by transmission which is disposed in front of a sheet of transparent material having a multitude of parallel opaque flaps substantially perpendicular to the wafer. In daytime use, light rays substantially perpendicular to the wafer pass through the sheet towards the rear of the wafer. For nightime use, the sheet reflects rearwardly of the wafer a part of the light rays coming from a lamp and the flaps stop the other part of these light rays.

Abstract: The present invention provides a probe for measuring the level of a liquid, including a conductor partially immersed in said liquid and whose degree of immersion depends on said variable level to be measured, the resistivity of which conductor depends on the temperature. The conductor is for example etched on an insulating support which is a better conductor of heat than air. The result is a very good linearity for rapid measurements, higher accuracy and a great mounting simplicity.

Abstract: A microprocessor transfers into a first so-called "fixed" zone of the memory the intermediate total distance travelled since the vehicle was put on the road and, in a second so called "journey" zone of the memory the successive partial distances travelled between each power supply cut off, the successive partial distances being transferred into the cells of the journey zone of the memory each time the power is switched off.

Abstract: In a liquid level detector of the type comprising a fixing rod bearing a winding over virtually the whole of its height, an annular float mounted around the rod and bearing at least one conducting blade constantly in contact with the winding, a warning device comprising a conducting rod sliding in a bore made in the float, the bore having its axis substantially parallel to the axis of the fixed rod, the conducting rod comprising a retaining device, and a conducting surface fixed to the lower end of the fixed rod, the arrangement being such that the conducting rod projects downwardly from the float when the level is higher than a determined warning level and comes into contact with the conducting surface when this level is reached, and electrical connections connecting the winding, the conducting surface, the or each conducting blade and the conducting rod to output terminals, the conducting rod extends at its top end in a supple loop made of conducting wire located in a plane substantially perpendicular to th

Abstract: A sensor for detecting the level of a liquid, comprising a conducting wire whose resistance has a high coefficient of temperature, the wire forming at least one pair of substantially parallel strands, adjacent connection pieces to which the ends of the wire are fixed, a tubular housing open at its upper and lower opposite ends, a spring having one end connected to the wire at the junction of its strands and its other end hooked to a lower holding piece fixedly mounted at the lower end of the tubular housing, and provided with an axial passage for a removable assembly spindle, an upper holding piece for holding the connection pieces, the upper holding piece being slidable in the tubular housing and fixedly mounted near the upper end of said housing and being provided with an axial passage with abutment for the removable assembly spindle.

Abstract: A device for measuring the level of a liquid, comprising a high temperature coefficient sensor immersed in the liquid, a detection circuit connected to the sensor for delivering a voltage indicative of the level of liquid, a memory circuit to which said voltage is applied, a saw-tooth signal generator circuit and, a comparator. The output signals of the memory circuit and of the saw-tooth signal circuit are coupled to input terminals of the comparator, and a display galvanometer is connected to the output of said comparator.

Abstract: A daily mileage recording unit, of the type comprising a plurality of drums mounted side by side on the same shaft and supported in rotation by a frame, a swinging member mounted to pivot with respect to the frame, a series of gears carried by the swinging member, each disposed between two drums to displace one drum by one graduation when the preceding drum has effected a complete revolution, a sliding member guided in translation in the frame and provided with a push button, a mechanism connecting the sliding member to the swinging member to pivot the latter when the push button is displaced, a cam rigidly locked with each drum and an actuator associated with each cam and carried by the swinging member for returning to zero the corresponding drum when the push button is actuated, a square rigidly locked with each gear and ramps carried by the frame which are engaged by respective squares during the pivoting of the gears, the contact surface of the ramp being a circular sector centered on the pivoting axis.