Locking screw mechanism that requires minimized loosening force

摘要

A locking screw mechanism includes an improved screw nut for minimizing the force required for loosening the locking screw mechanism when an object is clamped therein. A locking screw mechanism includes a screw head disposed on a screw shaft and a screw nut threaded about the screw shaft. The screw nut includes a back screw nut threaded about the screw shaft. The back screw nut has a nut holding portion and a contact ring surface. The screw nut also includes a front screw nut disposed around the nut holding portion of the back screw nut. The front screw nut is disposed toward the object that is being clamped. The screw nut further includes a holding ring disposed around the nut holding portion of the back screw nut for holding the front screw nut to the back screw nut. The contact ring surface of the back screw nut turns against the front screw nut to press the front screw nut against the object when the back screw nut is threaded toward the object. In addition, the front screw nut is stationary, and the contact ring surface of the back screw nut turns against the front screw nut when the back screw nut is dethreaded away from the object to loosen the screw nut from the clamped object. The contact ring surface has a smaller area than the portion of the front screw nut that contacts the clamped object to minimize frictional force from the contact ring surface turning against the front screw nut such that a force required for dethreading the back screw nut away from the clamped object is minimized.