Track ball base structure

A track ball base structure comprising a single-piece body having:

• a housing to receive a ball and an encoder wheel therein being composed of a plurality of standing plates in the top of said body with extruding portions in the upper end of which to get secure connection to a cover;
• a central circular recess with an opening bottom to hold said ball therein;
• a plurality of ball bearing holes evenly distributed around the upper rim of the circular panel in said housing with an inner rectangular plate inside the uppermost of each said hole for admitting ball bearings therein and at the same time holding them in place;
• two strip slots and the corresponding pairs of locking means working together in order to hold said encoder wheel wherein the holding condition can be enhanced due to a lateral gravity force from said ball if sitting in said central circular recess;
• two locking holes in platforms outer to said housing through which said single-piece body can be screwed up onto an integrated circuit plate by a bolt;
• a bracket-shaped fixture in the bottom of said single-piece body being provided to substantially engage with a block on which a photoemitter and a photodetector are located in pair.