Rotary encoder producing two output signals

A rotary encoder for producing a first output signal and a second output signal comprising:

• a rotary wheel having an inside wall;
• a frame for supporting the rotary wheel;
• an elastic means disposed on the frame for providing elastic force to the inside wall of the rotary wheel;
• a plate mounted on and rotating with the rotary wheel, the plate being provided with a plurality of apertures arranged at a predetermined pitch circularly around an axis of rotation of the plate;
• an axial rod having a distal portion and extending perpendicularly from the plate;
• a switch disposed in proximity to the distal portion of the axial rod, wherein pressure applied to the rotary wheel will cause the elastic means to compress and shift the axis of the wheel and plate such that axial rod contacts the switch and produces the first output signal;
• a light transmitter provided on one side of the plate;
• and
• a light receiver provided on the other side of the plate;
• wherein the light transmitter and light receiver are arranged so that light from the light transmitter travels through an aperture in the plate and is received by the light receiver when rotation of the plate is such that the aperture and the light transmitter are aligned, and light from the light transmitter is blocked by the plate when rotation of the plate is such that an aperture and the light transmitter are not aligned;
• wherein the receiving or not receiving of light by the light receiver produces the second output signal.