A fitting assembly configured to visibly indicate nut tightness when coupling a first component to a second component is disclosed. The fitting assembly comprises a nut comprising a threaded portion and a chamber portion, wherein the chamber portion comprises one or more through-holes. The fitting assembly also comprises an indicator slidably disposed within the chamber portion, a retainer assembly disposed within the chamber portion and configured to interlock with an inner surface of the nut, and a spring disposed within the chamber portion between, and engaging, the indicator and the retainer assembly. The retainer assembly is configured to interface with the spring to retain the spring within the chamber portion. The fitting assembly is configured to receive the first component and the second component such that, when the nut is rotated, a visibility of the indicator through the one or more through-holes changes.

A fitting assembly configured to visibly indicate nut tightness when coupling a first component to a second component is disclosed. The fitting assembly comprises a nut comprising a threaded portion and a chamber portion, wherein the chamber portion comprises one or more through-holes. The fitting assembly also comprises an indicator slidably disposed within the chamber portion, a retainer assembly disposed within the chamber portion and configured to interlock with an inner surface of the nut, and a spring disposed within the chamber portion between, and engaging, the indicator and the retainer assembly. The retainer assembly is configured to interface with the spring to retain the spring within the chamber portion. The fitting assembly is configured to receive the first component and the second component such that, when the nut is rotated, a visibility of the indicator through the one or more through-holes changes.

A signal acquiring method is provided using a plurality of fasteners with sensing elements configured to generate electrical signals as a function of the operating conditions of a plurality of readers, and an acquiring system. The method involves generating one or more electrical signals by means of the sensing elements, mechanically connecting the readers to the fasteners, and transferring the signals to the acquiring system by means of the readers.

A signal acquiring method is provided using a plurality of fasteners with sensing elements configured to generate electrical signals as a function of the operating conditions of a plurality of readers, and an acquiring system. The method involves generating one or more electrical signals by means of the sensing elements, mechanically connecting the readers to the fasteners, and transferring the signals to the acquiring system by means of the readers.

A rotation indication device for a rock bolt including a central rod with a threaded trailing portion. The rotation indication device includes a blind nut having a threaded central recess for engaging the threaded trailing portion and a visual indication means provided at a bottom portion of the central recess and configured such that upon movement of the threaded trailing portion of the central rod into the bottom portion of the central recess, the central rod forces at least a portion of the visual indication means to move through a passage in the blind nut between the bottom portion of the central recess and the outside of the blind nut.

A rotation indication device for a rock bolt including a central rod with a threaded trailing portion. The rotation indication device includes a blind nut having a threaded central recess for engaging the threaded trailing portion and a visual indication means provided at a bottom portion of the central recess and configured such that upon movement of the threaded trailing portion of the central rod into the bottom portion of the central recess, the central rod forces at least a portion of the visual indication means to move through a passage in the blind nut between the bottom portion of the central recess and the outside of the blind nut.

A rotary fastening device includes a rotating axial member and an inertia member. The rotating axial member includes a base body, an input end, an output end and an engaging portion. The input end is disposed at one end of the base body and selectively connected to a wrench. The output end is disposed at the other end of the base body. The engaging portion is disposed on the base body. The inertia member is detachably connected to the rotating axial member, and includes a gravity portion and an engaging hole. The gravity portion is extended toward the output end of the rotating axial member so as to form an annular space. The engaging hole is communicated to the annular space.

Disclosed is a fastener assembly comprising: a bolt member, comprising a bolt head and a shank, at least a part of which is screw threaded; a nut member for threaded engagement with the shank; a first drive element allocated to the bolt member and a second drive element allocated to the nut member, each drive element comprising a body and adapted for engagement by a corresponding tool. The body of the first drive element is joined to the bolt member by a first interposed interlayer structure. The body of the second drive element is joined to the nut member by a second interposed interlayer structure. The first interlayer structure is adapted to fracture in response to relative rotational and/or tensile force applied to the first drive element. The second interlayer structure is adapted to fracture in response to relative rotational and/or tensile force applied to the second drive element.

A fittable and releasable fastener includes a head which has a fitted and released portion and a fastening portion; and a fitting and releasing piece which has a fitting and releasing portion. Accordingly, when the fitting and releasing portion fits to the fitted and released portion, an external turning force is applied to the fitting and releasing piece or the head to make the fastening portion combine with at least one object. After the fastening portion is combined with the object, the fitting and releasing portion would release the fitted and released portion to limit the force or the force interval applied on the fastening portion for preventing excessively locking if the force is continuously applied.

A fittable and releasable fastener includes a head which has a fitted and released portion and a fastening portion; and a fitting and releasing piece which has a fitting and releasing portion. Accordingly, when the fitting and releasing portion fits to the fitted and released portion, an external turning force is applied to the fitting and releasing piece or the head to make the fastening portion combine with at least one object. After the fastening portion is combined with the object, the fitting and releasing portion would release the fitted and released portion to limit the force or the force interval applied on the fastening portion for preventing excessively locking if the force is continuously applied.