US Patent 7286114 Track ball structure

A track ball structure for controlling movements of a cursor comprises a body, a capacity in the body, a track ball housed in the capacity having a portion exposed outside the capacity for controlling the movements of the cursor, and a plurality of sensors located in the capacity surrounding the track ball for detecting pressure directions. When the track ball is rollable continuously in a selected direction to compress the sensors so that the cursor is moved continuously in the selected direction. Thus, the track ball structure uses less part of a hand to control the track ball simply, conforms to human engineering, and moves the cursor to an objective position in a short time.