Development of a Piezoelectric Screwdriver for Recessless Screws

摘要

Screw's are widely used because of their ease of use and very high joint force. Screws can be tightened very easily using plus- or minus screwdrivers. However, the cross- or minus-shaped recess on the screwhead causes a lot of problems. First, screws can be too easily loosened by screwdrivers, which means it becomes very easy to dismantle parts that should not be dismantled. Second, the recess makes a machine less aesthetically pleasing. Third, many screwdrivers of different diameter must be available. Fourth, if the recess is damaged, it becomes difficult or impossible to tighten or loosen the screw. To solve these problems, we propose a recessless screw. Recessless screw provides ultimate tamper-resistance. The proposed screwdriver uses piezoelectric cells to tighten or loosen recessless screws. Piezoelectric cells vibrate ultrasonically, generating rotation and tightening torque. The principle of the proposed screwdriver is examined by experiments whose results show the high potential of the piezoelectric screwdriver.