Patent attributes
A nut main body has a slanted hole with a smaller inner end portion having a plurality of stepped portions of differing height. This gives the slanted hole a differing depth relative to a large-diameter end portion of the slanted hole at a plurality of locations about a circumference of the slanted hole. A plurality of nut segments are slidable within the slanted hole and come into contact with at least one of the stepped portions. The nut segments have screw threads at an inner wall surface. A washer is provided at a large-diameter side of the plurality of nut segments. A bias spring is attached within the nut main body so as to urge the plurality of nut segments towards the small-diameter side of the nut main body with the washer therebetween. A stopper piece holds the bias spring within the nut main body.