A self-locking nut includes a main-nut body and a deformable-nut body. The main-nut body has a recess leading into an interior threaded bore forming x turns of an internal thread therein. The deformable-nut body has an outer flange and an interior threaded nore forming y turns of an internal thread therein. The outer flange of the deformable-nut body is fixed to the main-nut body such that a relief space is formed between the deformable-nut body and the recess. A ratio of x:y is about 2:1.

A bolt includes a shank having a first end, a second end, a first external thread proximate to the first end, and a second external thread proximate to the second end. The first external thread twists in a first direction, the second external thread twists in a second direction, and the first direction is different from the second direction. The first external thread includes a minor diameter, the second external thread includes a major diameter, and the minor diameter of the first external thread is greater than the major diameter of the second external thread.

A combination nut assembly includes first and second tightening nuts, each engageable with a bolt and having an interior frustum-shaped fitting socket and a dual frustoconical locking nut engageable with the bolt and elastically deformable and consists of two exterior frustum-shaped half locking nut members identical in geometric configuration and symmetrically inverted in position integrally connected together as a single part with their larger ends jointly connected and located between the first and second tightening nuts when assembled. Each half locking nut member protrudes an axial distance “e” from a bearing surface of the tightening nut in an assembled position. Axial distance “e” is defined by p>e≥α/tan θ, where: “θ” is cone generating angle; “α” is perpendicular backlash between flanks of threads of the bolt and locking nut in an ordinarily engaged position; and “p” is locking nut pitch.

A self-locking nut includes a main-nut body and a deformable-nut body. The main-nut body has a recess leading into an interior threaded bore forming x turns of an internal thread therein. The deformable-nut body has an outer flange and an interior threaded bore forming y turns of an internal thread therein. The outer flange of the deformable-nut body is fixed to the main-nut body such that a relief space is formed between the deformable-nut body and the recess. A ratio of x:y is about 2:1.

A locking nut includes a first nut, including a nut base and a screwing portion protruding outward from a face of the nut base, where the screwing portion is provided with a plurality of longitudinal sectional grooves in a spaced manner, such that the screwing portion is formed with a plurality of screwing claw bodies, and a first inner threaded wall is provided on each of inner walls of the screwing claw bodies, and is used for threadedly connecting to a bolt; and a pressing ring, mounted and located outside the screwing portion of the first nut, where an inner wall of the pressing ring includes a pressing inner-wall for pressing outer walls of the screwing claw bodies of the screwing portion.

The present disclosure disclosures a mounting and dismounting nut structure. The mounting and dismounting nut structure comprises a first body, a second body, a plurality of threaded blocks, and a limiting member. Inner walls of the plurality of threaded blocks comprise internal threads, and outer walls of the plurality of threaded blocks comprise second inclined surfaces. When the mounting and dismounting nut structure surrounds the threaded rod and is pushed towards a countertop, the plurality of threaded blocks move toward a center axis of the plurality of threaded blocks, and the second body rotates to drive the plurality of threaded blocks to be locked with the threaded rod. When the plurality of threaded blocks is locked with the threaded rod, the limiting member supports the plurality of threaded blocks in an axial direction of the plurality of threaded blocks.

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 self-locking nut includes a main-nut body and a deformable-nut body. The main-nut body has a recess leading into an interior threaded bore forming x turns of an internal thread therein. The deformable-nut body has an outer flange and an interior threaded bore forming y turns of an internal thread therein. The outer flange of the deformable-nut body is fixed to the main-nut body such that a relief space is formed between the deformable-nut body and the recess. A ratio of x:y is about 2:1.

A fastening device, fixing an exhaust manifold (12) on a cylinder head (14) of an internal combustion engine, has a contact surface (20) supported relative to a cylinder head contact surface (22). A fastening edge area (16) has a wedge fastening flange area (24) with a fastening element support surface (26) inclined in relation to the contact surface (20) that has a wedge angle (W.sub.1). A fastening element (38) is pressed against the fastening element support surface (26) with a fastening flange support surface (40) with a fastening bolt unit (30) supported in relation to the cylinder head (14). The wedge angle (W.sub.1) and a coefficient of static friction () of the frictional interaction of the fastening element (38) in relation to the exhaust manifold (12) is defined by: 0<W.sub.1<2 tan.sup.1 (), in which W.sub.1 is the wedge angle, and if the coefficient of static friction.