A pivot-mounting device has a lower nut (4) is fixing a bolt (2) to an object (A), and an upper nut (3) having a boss (32) rotatably supporting a rotatable member (B) is tightened on the bolt (2). A lower nut (4) includes an engagement recess (41) into which the boss (32) can be fitted with the outer peripheral surface of the boss (32) and the inner peripheral surface of the engagement recess (41) each being a straight cylinder shape. The boss outer peripheral surface (32) is slightly eccentric relative to a female thread hole (3a).

The present disclosure relates to a fastener and cap that are used as part of a fastener system to lock the fastener in place relative to a compatibly threaded shaft. In a preferred embodiment, the locking feature is utilized in vehicles, such as in aircraft.

There is provided an implant having a slack prevention function by an eccentric fitting structure. An engaging shaft 53, which is decentered with a screw shaft 52, is provided at the end of an abutment screw 5, and is engaged with an engaging hole 45 provided in the bottom of a screw hole 44, into which an abutment screw 5 is screwed, and thus, the screw shaft 52 is inclined to and eccentric from the screw hole 44. Thereby, the screw shaft 52 comes to be strongly pressed partially in a circumferential direction toward the screw hole 44, so that internal stress in the horizontal direction is accumulated on the screw shaft 52. The screw 5 is threaded with maintaining prevailing torque caused by the internal stress, which enables the screw 5 to be fastened to the right position.

It is made possible to give prevailing torque to an adjustment bolt in a simple manner without troublesome adjustment work. An anti-loosening adjustment bolt assembly includes: a cylindrical pipe (6) adapted to be fitted on the screw shaft (2a) of the adjustment bolt (2); and a nut (7) having a threaded hole for allowing the screw shaft (2a) to be threadably mounted thereon; the bottom of the nut (7) includes a recess (7a) adapted to allow the upper end of the cylindrical pipe (6) to be fitted therein; the inner peripheral surface of the recess (7a) is a taper surface decreasing in diameter toward the interior; and the axis of the taper surface is slightly eccentric from the axis of the threaded hole such that, when the nut (7), threadably secured to the screw shaft (2a), is screwed toward the cylindrical pipe (6), a circumferential portion of the eccentric taper surface comes into pressure-contact with the upper end of the cylindrical pipe (6) and the axis (Q) of the threaded hole of the nut (7) is eccentric and/or inclined from the axis (0) of the screw shaft (2a) to generate prevailing torque depending on the amount of tightening of the nut (7) on the adjustment bolt (2).

Provided is a nut that resists being loosened and is easy to be tightened. A nut 600 includes a nut main body 10 having a tapped hole 30 formed therein; an annular member 41 formed on the side of a top surface of the nut main body 10; and an outer frame member 45 formed on the side of an outer edge of the annular member 41. The annular member 41 includes a second end portion 42b in contact with a top surface 11 of the nut main body 10 and a first end portion 42a located opposite to the second end portion 42b. A top surface of the first end portion 42a is located above a top surface of the second end portion 42b. A first gap 40 is formed between the first end portion 42a and the top surface 11 of the nut main body 10. A second gap 49 is formed between a side surface of the annular member 41 and an inner wall 47 of the outer frame member 45. The top surface of the first end portion 42a of the annular member 41 is located above a top surface 46 of the outer frame member 45. The inner wall 47 of the outer frame member 45 is inclining while tapering in an upward direction.

A novel pivot-mounting device is provided that can accommodate various thicknesses of rotatable members and facilitate repeated attachment and detachment and that can prevent loosening due to vibration.

A lower nut (4) is used to fix a bolt (2) to an object to which a member is to be attached (A), and then an upper nut (3) having a boss (32) that rotatably supports the rotatable member (B) is tightened on the bolt (2). The lower nut (4) includes an engagement recess (41) into which the boss (32) can be fitted; the outer peripheral surface of the boss (32) and the inner peripheral surface of the engagement recess (41) are each formed into a straight cylinder shape; and the outer peripheral surface of the boss (32) is slightly eccentric relative to the female thread hole (3a) such that the boss (32) engages the engagement recess (41) to produce, in both nuts (3, 4), pressing forces in a direction perpendicular to the axis.

Provided is a nut that resists being loosened and is easy to be tightened. A nut 600 includes a nut main body 10 having a tapped hole 30 formed therein; an annular member 41 formed on the side of a top surface of the nut main body 10; and an outer frame member 45 formed on the side of an outer edge of the annular member 41. The annular member 41 includes a second end portion 42b in contact with a top surface 11 of the nut main body 10 and a first end portion 42a located opposite to the second end portion 42b. A top surface of the first end portion 42a is located above a top surface of the second end portion 42b. A first gap 40 is formed between the first end portion 42a and the top surface 11 of the nut main body 10. A second gap 49 is formed between a side surface of the annular member 41 and an inner wall 47 of the outer frame member 45. The top surface of the first end portion 42a of the annular member 41 is located above a top surface 46 of the outer frame member 45. The inner wall 47 of the outer frame member 45 is inclining while tapering in an upward direction.

An object of the present invention is to provide an anti-loosening device that exhibits its anti-loosening effect by means of an eccentric fit between a protrusion 12 of a nut 10 and a recess 22 in a nut 20, wherein the inclination of the nut 20 relative to the nut 10 when they have been tightened is minimized. The outer peripheral surface of the protrusion 12 and the inner peripheral surface of the recess 22 are constructed in such a manner that, with the nuts screwed to a threaded shaft S and an eccentric fit established between the protrusion 12 of the nut 10 and the recess 22 in the nut 20, the tapered outer peripheral surface portion 12a of the protrusion 12 interferes with the tapered inner peripheral surface portion 22a of the recess 22 along part of the circumference while a gap is formed between the distal-end outer peripheral surface portion 12b of the protrusion 12 and the closer-to-bottom inner peripheral surface portion 22b of the recess 22 along the entire circumference.

Disclosed is a ring type locknut, where a frustum-shaped internal thread concave cavity is arranged on a nut, inside which an annular member with frustum-shaped internal and external threads matching the concave cavity nut is provided, an eccentric value based on a specification thread fit clearance is set between internal threads and external threads of the annular member, so that when the annular member is screwed into a bolt together with the nut for locking, the expected objective that the nut will not loosen by only locking a single structure is achieved thanks to a comprehensive effect of the formed original nut structure, the eccentricity of the annular member and the structure of multiple properties of the tapered thread; the single-structure nut is used in a superposed mode, or the annular member is arranged on another nut, so that the overall anti-loosening effect is improved by the double-nut structure.