Patent ID: 9664534
Date: 2017-05-30
CPC Classifications: G01D,G01R,G04C

Claim:
1. An electromechanical apparatus comprising a wheel set and an analogue indicator member which are integral in rotation, a stepping motor, an electronic control circuit arranged to control the stepping motor, a drive train connecting the stepping motor to the wheel set and to the analogue indicator member, and a capacitive detection device, the drive train having a ratio such that the stepping motor causes the wheel set to make exactly one complete revolution in a determined integer number of motor steps, so that the motor steps subdivide one complete revolution of the wheel set into said integer number of mutually equidistant angular positions, and the capacitive detection device comprising a rotor integral in rotation with the wheel set, a stator and an electronic measuring circuit, the stator comprising a first pair of electrodes having a first capacitance, the rotor being adapted such that the value of the first capacitance depends on the angular position of said rotor, and the electronic measuring circuit being arranged to generate and to provide to the electronic control circuit a signal dependent on the value of the first capacitance; wherein the stator includes a second pair of electrodes having a second capacitance, the value of the second capacitance depending on the angular position of said rotor, wherein the pairs of electrodes and the electronic measuring circuit are configured such that the signal is representative of a difference between the respective values of the first and of the second capacitance, and wherein the electronic control means contain a stored correspondence table which contains reference values for the signal as a function of the angular position of the rotor for said mutually equidistant angular positions of the wheel set.