Relating to a track ball device for manipulating a cursor moving on a display
screen of an electronic apparatus, a track ball device being manipulated precisely
while generating a click feel when a ball is rotated, having a small play angle
and small size is presented. Beneath the center of the ball, the ball is rotatably
supported by four rollers. The section of a contacting portion of the rollers contacting
with the ball is a circular sawtooth profile, and the directions of the sawtooth
serrations of opposite rollers are reverse to each other. Rollers 2 to 5
have switches as rotation amount detecting units. Further, X roller and Y roller
contacting with the outer circumference in the orthogonal direction as seen from
above the ball, and third roller hold the ball rotatably. Plural undulations are
formed on the outer circumference of large-diameter contacting portions of the
X roller and Y roller 3 of circular shaft shape. Rotary encoders are coupled
to individual rollers.
