A loosening detection structure used to detect loosening of a bolt includes a material that is disposed between a fixing subject steel plate and a head portion of a metal bolt for fixing the steel plate and either attached to a seating surface of the head portion of the bolt or attached to a washer disposed between the steel plate and the head portion of the bolt, and that has electrical characteristics that vary in response to variation in a force for fastening the bolt to the steel plate.

A torque detection device includes a base, a load sensing member, a push member, a transmission module, and a drive module. The push member has a first extension wall and a second extension wall. The transmission module includes two adjustable transmission sets each including a torque transmission part. The torque transmission part respectively rests on the first extension wall and the second extension wall of the push member. The torque transmission part of the transmission module applies a force to push and press the push member reciprocatingly. The push member transmits the force of the torque transmission part to the load sensing member which cooperates with an electronic device to measure the maximum static friction torque of a detected workpiece.

A torque detection device includes a base, a load sensing member, a push member, a transmission module, and a drive module. The push member has a first extension wall and a second extension wall. The transmission module includes two adjustable transmission sets each including a torque transmission part. The torque transmission part respectively rests on the first extension wall and the second extension wall of the push member. The torque transmission part of the transmission module applies a force to push and press the push member reciprocatingly. The push member transmits the force of the torque transmission part to the load sensing member which cooperates with an electronic device to measure the maximum static friction torque of a detected workpiece.

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.

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.

A tool is equipped with a torque sensor, suited for a tightening task of a fastening component of a device such as a fluid control system that requires a large number of fastening components for assembly and has a narrow space for access to the fastening components, and capable of automatically detecting a tightening torque. The tool includes a torque sensor capable of detecting a tightening torque for tightening a fastening component acting on a bit. The torque sensor initiates measurement of the tightening torque when the tightening torque detected exceeds a set threshold value, completes measurement when the tightening torque detected falls below the set threshold value and a set time elapses, and outputs torque-related data formed on the basis of measurement data from measurement initiation to measurement completion and including a measurement time. The torque-related data includes a peak value of the measurement data.

A tool is equipped with a torque sensor, suited for a tightening task of a fastening component of a device such as a fluid control system that requires a large number of fastening components for assembly and has a narrow space for access to the fastening components, and capable of automatically detecting a tightening torque. The tool includes a torque sensor capable of detecting a tightening torque for tightening a fastening component acting on a bit. The torque sensor initiates measurement of the tightening torque when the tightening torque detected exceeds a set threshold value, completes measurement when the tightening torque detected falls below the set threshold value and a set time elapses, and outputs torque-related data formed on the basis of measurement data from measurement initiation to measurement completion and including a measurement time. The torque-related data includes a peak value of the measurement data.

An optical sensor includes a tube-shaped base formed from a metal, an optical fiber member received inside the base, and a sensor head formed from monocrystalline alumina and bonded to the base to be optically connected with the optical fiber member. The sensor head is provided with a first cavity including a first reflection surface configured to reflect a part of light introduced through the optical fiber member and a second reflection surface provided facing the first reflection surface and configured to reflect a part of the light reflected by the first reflection surface. A first interference light produced by an interference between the light reflected by the first reflection surface and the light reflected by the second reflection surface is output from the first cavity.

A looseness detection sensor for detecting looseness of a bolt for fixing a component, including: a resonance unit arranged adjacent to a head portion of the bolt and made of an insulating material confining a high-frequency signal input externally; and a conductive member in conduction with the component across the resonance unit, wherein the conductive member is a cap put on the head portion of the bolt and includes a protrusion contacting a surface of the component.

A fastener and a system, apparatus, and method for monitoring a fastener are described. The fastener includes a head portion, a shank portion, a transponder, and a compression spring, wherein the head portion includes a mounting portion, and wherein the transponder is disposed in the mounting portion of the head portion. The transponder is arranged to monitor the shank portion, and includes an ultrasonic sensor and a signal processing circuit. The ultrasonic sensor is affixed to a transducer hosting surface, and is urged against the transducer hosting surface by placement of the printed circuit board in the head portion with the compression spring intervening therebetween. The ultrasonic sensor communicates with the signal processing circuit via the compression spring. The signal processing circuit captures a signal from the ultrasonic sensor and transforms the signal into a parameter corresponding to a tensile force being exerted by the fastener.