Nippon Telegraph and Telephone Corporation

Tatsuya Hirahara

Hiroshi Kawano

To provide a screw fastening device that, when performing a screw tightening operation, can substantially reduce the running torque directly applied by external force to a screw driving device. A characteristic constitution is adopted that equips a screw driving device &#x3b1;with a device bodythat stacks a plurality of piezoelectric elementsandthat generate predetermined ultrasonic oscillations with the application of a predetermined AC voltage and excites mechanical oscillations in a predetermined direction on an oscillating end surfacebased on the ultrasonic oscillations; and a male distal end portionthat is correspondingly formed to be capable of fitting in a female recessformed in a screw &#x3b2;and integrally fixed to the device bodyon the oscillating end surfaceof the device bodyto impart running torque, which is directly applied to the screw driving device &#x3b1;by external force, and transmit the mechanical oscillations in the predetermined direction that the device bodyexcites to the screw &#x3b2;, with which contact is made by fitting in the female recess

Screw driving device and screw

To provide a screw fastening device that, when performing a screw tightening operation, can substantially reduce the running torque directly applied by external forceto a screw driving device. A characteristic constitution is adopted that is equips a screw driving device &#x3b1;with a device bodythat stacks a plurality of piezoelectric elementsandthat generate predetermined ultrasonic oscillations with the application of a predetermined AC voltage and excites mechanical oscillations in a predetermined direction on an oscillating end surfacebased on the ultrasonic oscillations; and a male distal end portionthat is correspondingly formed to be capable of fitting in a female recessformed in a screw &#x3b2;and integrally fixed to the device bodyon the oscillating end surfaceof the device bodyto impart running torque, which is directly applied to the screw driving device &#x3b1;by external force, and transmit the mechanical oscillations in the predetermined direction that the device bodyexcites to the screw &#x3b2;, with which contact is made by fitting in the female recess

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Kyoto, Japan

Tatsuya Hirahara