Abstract: The present invention provides a rotary switch mechanism comprising a dial unit and a position sensor that rotates as the dial unit rotates, with the rotational position of the dial unit determined based upon an output signal provided by the position sensor. The present invention allows the dial unit to assume a greater rotational angle range and also allows the number of dial steps to be increased by assuring the desired level of reading resolution for the sensor. The present invention includes a plurality of position sensors 13c-1, 13c-2 and 13c-3 and detection switches 16 and 17 the output signals of which are switched in correspondence to the rotational position assumed by the dial unit. The entire angle range over which the dial unit is allowed to rotate is divided into a plurality of range blocks, a specific position sensor is designated to one of these blocks and the position sensor engaged in operation is switched based upon the output signal provided by the detection switches 16 and 17.

Abstract: A rotary switch mechanism for an operation panel is designed such that the space on a printed board is ensured, the design of electronic parts on the printed board can be readily made, and the attachability of a switch is good. Drive pieces are arranged at predetermined intervals around the end of a rotary knob behind the operation panel, and a detection switch for detecting the passage and the direction of the passage of the drive pieces is disposed in or near the extent where the drive pieces move.