Patent attributes
A nut having a nut body, a spring case, a washer, and a nut body urging spring. The nut body has received in it at least three or more nut segments and a nut segment urging spring, where the nut segments are, when rotated in the tightening direction after a bolt is inserted into the nut segments, screwed on to the thread of the bolt inserted. The spring case is attached at its upper end to the outer circumferential surface other than the upper part of the nut body so that the spring case is rotatable together with the nut body. The washer is rotatably attached to the lower part of the spring case. The urging spring is installed such that its one end received in the spring case is connected to the spring case or to the nut body and the other end to the washer, so that the urging spring can constantly urge the nut body in the tightening direction when the nut body is screwed on the bolt. When the nut is fitted on the bolt and rotated in the tightening direction, at least the three or more nut segments are screwed on to the thread of the bolt, causing the nut body in which the nut segments are received to be constantly urged in the tightening direction, which eliminates play of the nut segments to keep the nut and the bolt in a state where they are reliably screwed to each other.
