The disclosure provides a bolt including a main body, a head portion and a thread portion. The main body has a central axis. The head portion connects the main body. The thread portion is connected to the main body and runs around the central axis. The thread portion has a bearing surface facing toward the head portion. The bearing surface is a continuous curved surface or has an inflection point. The bearing surface includes a concave curved surface, a convex curved surface and a flank surface. The concave curved surface connects the main body. The convex curved surface is located further away from the main body than the concave curved surface. One side of the convex curved surface connects the concave curved surface, and another side of the convex curved surface connects the flank surface.

A coupling bolt or pin, in particular a ball pin, with a coupling head, such as a ball head, and a thread shaft. The thread shaft comprises a thread in a longitudinal portion of the thread shaft, which extends parallel to a central longitudinal axis of the thread shaft. Within the longitudinal portion of the thread a thread inhibition is provided by means of which a frictional connection between the thread and a counter thread engaging therein and being present at a radial inner wall of a thread opening is increasable. A disc-shaped support structure is provided between the coupling pin and the thread, a radial extension of which is adaptable to a diameter of the thread opening so that the coupling pin is supportable against a lateral load with respect to the axis of the coupling pin within the thread opening.

A bolt includes a threaded shaft and a bolt head. The threaded shaft has a first end, a second opposing end, and an external thread. The first end includes a flared protrusion and the external thread is wrapped about the shaft and extends from the second opposing end to the flared protrusion. The bolt head includes an interior threaded bore for threadingly engaging the external thread of the threaded shaft, a front surface, and an opposing back surface having a recess configured to receive at least a portion of the flared protrusion of the threaded shaft therein.

A multi-piece locking fastener having an intermediate component exhibiting a plurality of interior threads arrayed in a first direction. A first fastener has a first enlarged head and a first stem exteriorly threaded in the first direction. A hollowed interior is formed in an end of the stem and exhibits a further plurality of interior threads extending in a second direction opposite the first direction. A second fastener has a second enlarged head and a second stem, upon which is configured a second exterior thread pattern extending in the second direction. The first fastener is installed through the intermediate component from a first direction, with the second fastener rotationally inter-engaging the exposed interior threads of the first fastener in the second direction until the second enlarged heads contact the intermediate component, with loosening of either of the first and second fasteners being prevented.

A multi-piece locking fastener having an intermediate component exhibiting a plurality of interior threads arrayed in a first direction. A first fastener has a first enlarged head and a first stem exteriorly threaded in the first direction. A hollowed interior is formed in an end of the stem and exhibits a further plurality of interior threads extending in a second direction opposite the first direction. A second fastener has a second enlarged head and a second stem, upon which is configured a second exterior thread pattern extending in the second direction. The first fastener is installed through the intermediate component from a first direction, with the second fastener rotationally inter-engaging the exposed interior threads of the first fastener in the second direction until the second enlarged heads contact the intermediate component, with loosening of either of the first and second fasteners being prevented.

The present disclosure provides an anti-loosening screw pair and an anti-loosening screw component. The screw pair includes a first screw component provided with a first screw thread and a second screw component whose outer wall surface is provided with a second screw thread. The first and second screw components are in threaded connection. In a direction of the first screw component being screwed into the second screw component, sides of the first and second screw threads pressing against each other are formed into force-bearing fitting faces respectively, and opposite sides thereof are formed into non-force-bearing fitting regions respectively. At least one of the force-bearing fitting faces and the non-force-bearing fitting regions of the first and the second screw components is provided with a stopper so as to prevent radial displacement between the first and the second screw components.

The present disclosure provides an anti-loosening screw pair and an anti-loosening screw component. The screw pair includes a first screw component provided with a first screw thread and a second screw component whose outer wall surface is provided with a second screw thread. The first and second screw components are in threaded connection. In a direction of the first screw component being screwed into the second screw component, sides of the first and second screw threads pressing against each other are formed into force-bearing fitting faces respectively, and opposite sides thereof are formed into non-force-bearing fitting regions respectively. At least one of the force-bearing fitting faces and the non-force-bearing fitting regions of the first and the second screw components is provided with a stopper so as to prevent radial displacement between the first and the second screw components.

A multi-piece locking fastener having an intermediate component exhibiting a plurality of interior threads arrayed in a first direction. A first fastener has a first enlarged head and a first stem exteriorly threaded in the first direction. A hollowed interior is formed in an end of the stem and exhibits a further plurality of interior threads extending in a second direction opposite the first direction. A second fastener has a second enlarged head and a second stem, upon which is configured a second exterior thread pattern extending in the second direction. The first fastener is installed through the intermediate component from a first direction, with the second fastener rotationally inter-engaging the exposed interior threads of the first fastener in the second direction until the second enlarged heads contact the intermediate component, with loosening of either of the first and second fasteners being prevented.

A multi-piece locking fastener having an intermediate component exhibiting a plurality of interior threads arrayed in a first direction. A first fastener has a first enlarged head and a first stem exteriorly threaded in the first direction. A hollowed interior is formed in an end of the stem and exhibits a further plurality of interior threads extending in a second direction opposite the first direction. A second fastener has a second enlarged head and a second stem, upon which is configured a second exterior thread pattern extending in the second direction. The first fastener is installed through the intermediate component from a first direction, with the second fastener rotationally inter-engaging the exposed interior threads of the first fastener in the second direction until the second enlarged heads contact the intermediate component, with loosening of either of the first and second fasteners being prevented.

Tie bolt and process for making such tie bolt having a shank and a nut, in particular a dead nut; wherein the nut is tightened and locked around a respective end of the shank, so as to form an indivisible body.