Electric chuck

An electric chuck, comprising

• a base;
• a fixed disk fixed under the base for positioning a work piece on;
• there being a space between the fixed disk and the base;
• a rotating shaft being arranged under the fixed disk in a rotatable manner;
• the rotating shaft having outer threads on an outer circumferential side thereof;
• a moving disk, the moving disk being arranged between the base and the fixed disk in a movable manner;
• the moving disk having a middle through hole, through which the rotating shaft is threadedly passed;
• a plurality of clamping jaws, the clamping jaws being connected to the fixed disk as well as the moving disk in a movable manner;
• and
• an electric motor, power of the electric motor being transmitted to the rotating shaft for causing rotation of the rotating shaft;
• the clamping jaws being going to be moved to an inwardly pivoted clamping position to hold a work piece positioned on the fixed disk when the rotating shaft is rotated so as to move the moving disk to one of upper and lower positions;
• the clamping jaws being going to be moved to an outwardly pivoted releasing position to release a work piece positioned on the fixed disk when the rotating shaft is rotated so as to move the moving disk to other one of upper and lower positions.