An intelligent bolt includes a head region and a threaded region. The head region includes a bolt cavity. A distance between the head region and a bottom end of the cavity changes in operation as a function of longitudinal stress applied between the threaded region and the head region, and the bolt includes a sensor arrangement for measuring changes in the distance. A distal end of the sensor arrangement is disposed adjacent to the bottom end, wherein changes in spatial position of the bottom end relative to the distal end occur as a function of changes in the stress applied to the bolt to define a gap “G” whose size varies depending upon the stress. Interrogating radiation transmission in operation via the gap “G” from a source to a corresponding radiation sensor of the arrangement generates a stress measurement signal that is processed for wireless communication.

Fixing device comprising a fixing member provided with a bearing head, a sensor provided with a detector of the mechanical force to which the fixing member is subjected, the detector being mounted in contact with the fixing member, and a connecting component which is electrically connected to the sensor, which is configured to transmit a measurement of a mechanical force provided by the sensor and which is mounted on the fixing member, the fixing member comprising a body which is mounted on the bearing head and which extends along a longitudinal axis protruding from the bearing head.

The invention relates to a solution for how to measure the strain in a washer mounted in a bolt assembly comprising a bolt, nut and washer. The invention concerns a strain measuring washer assembly comprising a plate shaped washer body, sound emitting means and sound detecting means, and a method for using such.

A tag configured to detect loosening of a fastening member fastened to a fastened part of an apparatus includes: a base sheet including a fastening member attached portion and a fastened part attached portion, the fastening member attached portion being attached to the fastening member, the fastened part attached portion being attached to the fastened part; a RFID chip mounted on the base sheet; an antenna circuit mounted on the base sheet while being connected to the RFID chip; and an electric conductor mounted on the base sheet while being connected to the RFID chip, the electric conductor being configured such that an electric property of the electric conductor changes when the fastening member is displaced relative to the fastened part attached portion.

A method for operating a monitoring system of at least one fastening device includes providing an identifier allocated to the at least one fastening device and a fastening property allocated to the at least one fastening device to a computer device of the monitoring system, and maintaining a digital twin of the at least one fastening device using the computer device by linking the identifier and the fastening property. The method further includes monitoring the at least one fastening device by evaluating the digital twin.

Screw having a head and a threaded cylindrical body, the head being provided with strain gauges arranged so as to be deformed in order to measure a stress within the screw, the gauges being connected or able to be connected to a power supply and to a determination unit for determining the value of at least one inner stress from the deformations of the gauges. The head has, on the upper face thereof, a conical hole having a revolution axis that is aligned with the revolution axis of the cylindrical body. The gauges are arranged on the wall of the conical hole so as to be deformed together with the conical hole and are oriented to measure at least one type of inner stress selected among the tension and the shearing.

A battery module containing a plurality of battery cells electrically connected to one another in series or in parallel, two contact surfaces (14a, 14b) for the purposes of tapping off a module voltage of the battery module (10) and at least one bolted joint device (22) for the purposes of fixing a component (12), in particular a current-conducting component, of the battery module (10), wherein the at least one bolted joint device (22) is provided with a sensor (26) for the purposes of determining a preload force applied to the bolted joint device (22).

A wheel nut or axle nut for vehicles, having a body, having a central threaded hole, having a peripheral wall, and having an abutment face at a lower side The nut also has a plurality of wrench faces on the peripheral wall of the nut body for tightening or releasing the nut by a tool which cooperates with the wrench faces. In the body at least one recess is provided in which a sensor element is arranged The sensor element is connected to a wireless interface which is configured to transmit a sensor signal of the sensor element wirelessly to an external reception unit.

A bolt axial force measurement method of the present invention includes: a probe insertion step of inserting a stepped protrusion of a probe into a stepped recess formed in a head of a bolt, the stepped protrusion being included in a probe to correspond to the stepped recess of the head; an elongation calculation step of calculating an elongation of the bolt during tightening, based on a bottom echo of an ultrasonic pulse emitted from the probe toward a bottom face of a shank of the bolt; and an axial force calculation step of calculating an axial force of the bolt, based on the elongation of the bolt.

A bolt includes a head portion on which a recess is formed. The recess has a bottom surface and a sidewall extending from a periphery of the bottom surface. The sidewall has a lower end defined by the bottom surface and includes an increased diameter portion and a reduced diameter portion. The increased diameter portion has an inner diameter larger than an inner diameter of the lower end of the side wall. The reduced diameter portion has an inner diameter smaller than the inner diameter of the increased diameter portion. The reduced diameter portion is located opposite to the bottom surface across the increased diameter portion.