Patent ID: 7220091

Claim:
A fastening nut for fastening onto a male threaded member, comprising: a base having a first insertion hole for receiving the male threaded member; a cover having a second insertion hole for receiving the male threaded member and having a circumferential wall; a plurality of nut segments defining a virtual single nut and arranged at regular intervals in a circumferential direction about a nut axis, wherein each of the nut segments is disposed between the base and the cover and is movable in a radial direction with respect to the nut axis; a plurality of control members corresponding to each nut segment, the control members disposed between each of the nut segments and the circumferential wall of the cover in order to prevent each nut segment from moving in the radially outward direction when the cover is rotated in a nut tightening direction; a plurality of relief recesses formed in the circumferential wall of the cover for each corresponding nut segment or the plurality of relief recesses formed in each nut segment, wherein the relief recesses are engageable with the corresponding control members to permit each nut segment to move in the radially outward direction when the cover has rotated in a nut loosening direction relative to the base.