Abstract: The nut is usually fixed by the axial force generated with the bolt fastening. However, the loosening force, which is larger than the axial stress, acts on the nut by the repetitive vibration or shock, whereby the loosening phenomenon of the nut generates. So it is necessary to prevent the loosening, the present invention threads an outer screw as the direction of an inner screw of the nut on an outer periphery of the flange or the shank of nut and screws together an lock nut with the flange or the shank. In doing so, it is possible to constantly prevent the loosening of the nut.

Abstract: A low torque nut is capable of easily generating a large axial force by a small torque to fasten and has stable anti-loosening qualities. The low torque nut includes a nut member having a screwed runner, an engagement portion, and plural screwed runners drilled from an outer periphery plane toward an inner diameter direction. The low torque nut also includes a ring-shaped saucer member rotatably mounted in a lower portion of the nut member, plural rolling elements that lie within a contact portion in an axial direction between the nut member and the saucer member, and a locking member that has an engagement groove being engaged with a spline groove and an inserting hole of a screw threadedly connecting to the screwed runner of the nut member.