Snap-on Technologies, Inc.

Thomas B Petruzzi

Bert Krivec

John A Braun

A miniature, adjustable torque limiting screwdriver includes an elongated hollow handle internally threaded at one end. A torque-limiting mechanism is disposed within the handle and includes a rigid shaft having a hex inner end and a plurality of flexible resilient fingers engageable with the hex. An adjusting collar encircles and engages the fingers and is threadedly engaged with the handle for axial movement to adjust the force with which the fingers grip the hex end of the shaft. The outer end of the shaft sockets a driver shank. When the handle is rotated it rotates the shank up to a predetermined torque, at which point the flexible and resilient torque members slip with respect to the drive surface portions of the shaft to prevent further torque application. The outer end of the shaft carries a gear member engaged by a spring-biased pin socketed in the handle, the gear teeth being arranged to accommodate a ratcheting rotation in one direction to permit relative rotation of the handle with respect to the shaft in one direction but to prevent relative rotation in the opposite direction.

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Rockaway, NJ, United States of America

Thomas B Petruzzi