In a management system for an attachment state of an attachment object, a sensor capable of detecting a value equivalent to stress of stress loaded, or a predetermined value from which the value equivalent to stress can be calculated, a washer storage unit storing identification information of a sensing washer, and a washer control unit transmitting the value equivalent to stress and the identification information of the sensing washer via a communication unit, are provided in the sensing washer between a bolt and a nut that attach an attachment object to a structural object. A management processing device acquires the value equivalent to stress and identification information of the sensing washer transmitted from the sensing washer, and presents the value equivalent to stress of the sensing washer of the identification information, or a corresponding stress value, as relational information with respect to a reference value stored in a storage unit.

The present invention relates to a screw nut equipped with sensors (2, 3) on its lateral surfaces.

An instrumented, load-sensing washer that can be used on a bolted joint to facilitate determining an axial clamping load of the bolted joint. The washer includes an annular washer body having first and second oppositely disposed axial ends and an outer circumferential sidewall. At least one strain gauge is provided on the circumferential sidewall and is configured to sense a deformation of the washer body do to clamping forces of the bolted joint. The washer further includes a communication assembly operatively coupled with the at least one strain gauge. The communication assembly may include an integrated circuit adapted to receive electrical signals from the at least one strain gauge related to the axial load borne by the washer.

A fitting assembly includes an indicator assembly that provides a visual indication of torque value to verify when the desired operational torque value is achieved. The fitting assembly includes a nut, and a visual indicator assembly positioned on the nut which has a plurality of visual indicators that provide a visual indication of a torque level being applied. A sleeve is attached to the nut and includes a window through which a portion of the visual indicators is visible based on the torque level being applied. A resilient member couples the sleeve to the nut. As the nut is rotated to apply torque to the nut, the resilient member biases the sleeve in a fixed position and the nut rotates relative to the sleeve, whereby the visual indicator assembly rotates relative to the sleeve to alter which portion of the visual indicator assembly is visible through the window to provide a visual indication of when the operational torque level is being applied. The fitting assembly includes a positive locking feature that interacts with a serrated portion of a nipple fluid connection to positively lock a position of the nut to prevent nut loosening.

A looseness detection structure configured to detect looseness between a bolt and a nut that fix two components including a conductive film configured to be attached on a surface of the component, the surface of the component including a hole into which the bolt is inserted, the conductive film being attached such that the conductive film is not directly conductive to the component, a part of the conductive film having a dimension relating to a half wavelength of a high-frequency signal propagating inside the components, and a non-conductive film between a surface of the component and the conductive film in a case where surfaces of the components are conductors, and a second conductive film on a surface of the component in a case where the surfaces of the components are insulators, the second conductive film being opposite to the conductive film.

A threaded fastener capable of torque detection includes: a head and a shank connected together, wherein the shank has a threaded peripheral surface; a neck formed at the junction between one end of the shank and the head; and at least one sensing element and a sealing element, both provided on the neck, wherein the sensing element is configured to detect deformation of the neck, and the sealing element seals the sensing element. The threaded fastener may further include a covering element that covers the sealing element. The threaded fastener can be deformed consistently, allowing the sensing element to obtain relatively accurate detection values.

A threaded joint arrangement with visual and tactile indication of correct tightening force, includes a threaded fastener having a fastener shaft and a fastener head, a biasing member, a first object provided with a cavity in a reference surface with a bottom surface provided with a through hole, and a second object with a threaded hole. The through hole is aligned with the threaded hole and the fastener shaft extends through the through hole and is in threaded engagement with the threaded hole. The biasing member is arranged in the cavity between the fastener head and the bottom surface and is compressed between the fastener head and the bottom surface in response to rotation of the threaded fastener. An alignment surface is movable by rotation of the threaded fastener between a first position outside the cavity, a second position flush with the reference surface and a third position inside cavity.

Deformable spacers and spacer assemblies absorb energy when flange bolts are subjected to compressive axial loads by plastically deforming, failing in shear, rupturing or in a combination of failure modes so the flange bolts and the flanges connected thereby are not damaged. One deformable spacer may have a hollow cylindrical body with a plurality of elongated slots there through. Another deformable spacer may have an annular stiffener extending inwardly from an inner surface of a hollow cylindrical body. A spacer assembly may include an inner cylindrical body, and outer cylindrical body, and an annular shoulder extending from one of the bodies and engaged by the other body shears when a shear failure load is applied to the flange bolt. Another spacer assembly may include an annular belt around a cylindrical body so that the belt will rupture before the cylindrical body plastically deforms.

Improved systems and methods facilitate precise adjustment of wheel-end tapered roller bearing preload force on an axle spindle with a diameter, a longitudinal groove or flat, and a thread pattern to receive a hexagonal adjustment nut with six outer edges. A basic system includes a flat round inner washer having an inner diameter corresponding to the diameter of the axle, an outer diameter, an inner surface, and outer surface and an outer edge. The inner washer includes a tab or D-shape to cooperate with a groove or flat, respectively on the axle to ensure that the washer does not rotate following installation. A plurality of markings are provided on the outer surface or the outer edge of the inner washer, each marking indicating the amount of rotation needed to cause a 0.001″ lateral movement of the adjustment nut as a function of the diameter and thread pattern of the axle.

A tension indication device for a rock bolt includes a support washer, a cover member having a central hole for receiving a trailing portion of the rock bolt, and an indicator substance provided in a first space in the cover member or in a recess in the support washer for facing the nut. Upon rotation of the nut, indicator substance is forced out of the first space such that the indicator substance is visible at inspection of the rock bolt, thereby indicating that the rock bolt has been tensioned.