| 摘要 |
Parallel plates (15,16), mounted in the cooker hob or casing, support the motor (4) and house the gear-train (6,7,8,9), giving typically 100:1 reduction, whose input wheel (6) is fixed on the motor drive-shaft, the output wheel (9) being fixed on the spindle (5) of the gas tap (1). The spindle is aligned with and fixed to the operating shaft (11) of a potentiometer (10), also supported by the gear-train frame, whose output accurately represents the angular position of the tap. This output and a setting for the tap opening imposed by the user through a manually operated device (13), e.g. a knob or a capacitance effect touch control, are input to a comparator (12). The error signal (E) is processed by an electronic control unit (14) which operates so as to reduce the signal to zero, to this end driving the motor via a power interface based e.g. on an amplifier and transistor or thyristor. The reversible, typically DC, motor requires only a 20 g.cm torque rating. Using electronic type user controls, digital circuitry can be employed. Automatic gas shut-off, initiated by a flame-out detector on the burner, can be incorporated as a safety measure. |
