A fastener has a head and a shank extending from the head to a tip. The shank has a threaded distal portion that includes primary threads defining a major diameter, a minor diameter, and at least one helical rib or scalloped surface at the minor diameter. The at least one rib extends between adjacent primary threads of the threaded portion and extends in a helical configuration. The configuration of the fastener with helical ribs in the minor diameter reduces contact surface area between the fastener and building material substrate, like wood, during installation of the fastener, which thereby results in less torquing force required for installation.

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.

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.

A plunger rod system for syringes is provided. The system comprises at least one plunger and an associated rod for imparting force to the plunger. The rod comprises an end with a threaded member, and the threaded member comprises threads of a certain geometry that enable ease of installation of the rod within the plunger while also providing resistance to pull-out forces such as may be imparted when pulling or extracting the rod or plunger from a barrel.

A plunger rod system for syringes is provided. The system comprises at least one plunger and an associated rod for imparting force to the plunger. The rod comprises an end with a threaded member, and the threaded member comprises threads of a certain geometry that enable ease of installation of the rod within the plunger while also providing resistance to pull-out forces such as may be imparted when pulling or extracting the rod or plunger from a barrel.

A threading indicating bolt comprises a shank and a head, said head defining a trailing end and said shank defining a leading end of said bolt, said shank comprising a threaded trailing portion having a thread pitch, and a threaded leading portion, said threaded leading portion having a thread start, wherein said threaded leading portion extends in the axial length of said leading portion from said thread start to the threaded trailing portion for a length (L) being three times the thread pitch of said threads of said trailing portion; and wherein a torque is needed to thread a matching nut onto said bolt; said leading portion of said bolt comprising a mechanical threading indicating element adapted to increase said torque needed to thread a matching nut onto said bolt, while said matching nut is in threaded engagement with the mechanical threading indicating element arranged on said leading portion of said bolt; said increase of said torque being in comparison to a required run-down torque when said matching nut has been threaded onto said bolt past said leading portion and onto said threaded trailing portion. A threading indicating system and a method for assembling a bolted joint are also disclosed.

A bolt and a method for manufacturing the bolt are provided. The bolt includes a screw cap and a bolt bar, the bolt bar includes a positioning bar, a flexible bar and a threaded portion, the positioning bar is connected to one end of the screw cap, and the flexible bar is connected to the positioning bar and the threaded portion respectively. Wherein, an anti-shearing stand is formed on the flexible bar. The threaded portion includes standard threads and transition threads, the transition threads are formed between the flexible bar and the standard threads, and a thread height of the transition threads is smaller than a thread height of the standard threads, wherein the thread height of the standard threads keeps constant. The force distribution of the threads can be optimized, and the threads can effectively cooperate with the threads of the nut.

A bolt and a method for manufacturing the bolt are provided. The bolt includes a screw cap and a bolt bar, the bolt bar includes a positioning bar, a flexible bar and a threaded portion, the positioning bar is connected to one end of the screw cap, and the flexible bar is connected to the positioning bar and the threaded portion respectively. Wherein, an anti-shearing stand is formed on the flexible bar. The threaded portion includes standard threads and transition threads, the transition threads are formed between the flexible bar and the standard threads, and a thread height of the transition threads is smaller than a thread height of the standard threads, wherein the thread height of the standard threads keeps constant. The force distribution of the threads can be optimized, and the threads can effectively cooperate with the threads of the nut.

Disclosed is a fastener that includes a thread having a groove formed therein to provide a loosening resistance due to a deformation of the thread, the deformation resulting from a threshold axial force applied to the thread by a receiving structure.

The present invention relates to an anti-loosening bolt coupled to a bolt and a spring and, more specifically, to an anti-loosening bolt which can: prevent the bolt from being unintentionally loosened by a rotating object or by continuous long-time or momentary vibration; be fixed on a wall; be combined with a nut; prevent a periodic shaking phenomenon; and be reused.