Patent ID: 6386808
Filing Date: 2002-05-14
Classification: F16B

Abstract:
A structure of a nut internal thread portion for preventing looseness, wherein an exit end portion of the internal thread portion to be engaged threadedly with an external-thread member is taperingly contracted on the entire circumference thereof so as to have smaller minor diameters of internal thread than a middle portion to form a contracted internal thread portion having a conical section,wherein ridges of the contracted internal thread portion are provided in the form of circumferentially continuing corrugation to form a group projections projecting toward the center of the contracted internal thread portion and which has a group of depressions depressed away from the center of the contracted internal thread portion, wherein both the projections and the depressions are said taperingly contracted and wherein, when the nut is adapted to engage an external-thread member with the internal thread portion, the group of projections in the corrugation of the ridges of the contracted internal thread portion press roots or flanks of the external thread member and are thereby, so as to clamp the external-thread member.