Patent ID: 8278912

Claim:
A twist-grip control device ( 1 ), for motor vehicles, comprising a stator portion ( 2 ) which is stationary in operation, a rotor portion ( 3 ) which is configured to be gripped and which is mounted such as to be manually rotatable about an axis (A-A) with respect to the stator portion ( 2 ), against the action of resilient opposing means ( 13 ) tending to recall the rotor portion ( 3 ) into a relative angular rest position, first and second permanent magnet means ( 11 a , 11 b ) connected to the rotor portion ( 3 ) in respective separate angular fields about said axis (A-A) and configured to generate respective predetermined angular distributions of magnetic field intensity about said axis (A-A), first and second magnetic field sensors ( 14 a , 14 b ) connected to the stator portion ( 2 ) in respective separate angular positions about said axis (A-A), and associated with the first and second permanent magnet means ( 11 a , 11 b ) respectively in order to provide, when the rotor portion ( 3 ) is rotated by a certain angle with respect to the stator portion ( 2 ), a respective first and second electrical signal indicating the relative angular position of the rotor portion ( 3 ), the first and second signals being correlated with one another in a predetermined relationship such that one of the signals is used as a control signal indicative of the extent of an associated controlled physical magnitude required by the user, and the other signal is used as a control signal to enable detection of the occurrence of operating malfunctions or failures when these signals are no longer correlated with one another in the predetermined relationship; and further comprising at least one further sensor means associated with the magnets ( 14 a , 14 b ) to provide a further signal in respect of the angular position field of the rotor portion ( 3 ) corresponding to a range of operation at idling speed of the engine of the motor vehicle.