A loosening detection device according to the present embodiment includes multiple washers having holes that allow bolts to pass therethrough, and including metals insulated from each other, a transmission line that electrically connects between the metals and between the metals of the washers, and a transmission line that includes a terminal pair at one end thereof, and that has the other end electrically connected to the metals of the washer. A resonance frequency is measured from the terminal pair to detect loosening of the bolts on the basis of a change in the resonance frequency.

A locking confirmation device of multiple electrode contacts includes an electrode, a terminal bolt, a sensing unit and a positioning bolt. The electrode includes an electrode thread and a positioning thread. The terminal bolt is used for locking a conductor and the electrode thread. The terminal bolt includes a positioning recess. The sensing unit includes an insulated cover, a first contact, a second contact, an elastic member and an voltage signal input connector. When the elastic member is extruded, a circuit is formed for returning a voltage signal of a node of the electrode. The positioning bolt is used for fixing a detection sensor assembly on the positioning thread. When a head portion of the positioning bolt is received within the positioning recess, the terminal bolt is led to a locking state by the head portion of the positioning bolt. Therefore, a fault of an electricity system is prevented.

There is provided a bolt sensor which detects a fastened state of a bolt. The bolt sensor includes a sensor body including a through hole into which a shaft of the bolt is to be inserted, a light guide extending along an outer periphery of the sensor body, and a light source configured to emit light to the light guide based on output of the sensor body.

A fastening device may include a first member configured for forceful engagement with a second member. The first member may include a sensor configured to emit at least a first photo-luminescent signal to a detector when at least a predetermined first torque level is applied to the first member when the first and second members are engaged.

This invention installs multiple miniature strain gauges inside a regular dimensioned bolt washer to accurately measure bolt preload. To enhance the strain gauge sensitivity, an alloy with low elastic modulus and high yield strength is selected to fabricate the metal washer. In addition, multiple gauges are connected in series to multiply the effective gauge length and enhance measurement sensitivity. Further, the stain gauges are encapsulated in the middle of the washer as opposed to on the external surface which offers much improved sensitivity and physical protection of the strain gauges.

A fastening device may include a first member configured for forceful engagement with a second member. The first member may include a sensor configured to emit at least a first photo-luminescent signal to a detector when at least a predetermined first torque level is applied to the first member when the first and second members are engaged.

A unitary tension and torque calibration apparatus consists of a unitary device which has a hollow rotary torque transducer for calibrating the torque of a rotating torque tightening tool. At the same time the torque of the tool is being calibrated, a reaction arm attached to the transducer reacts against rotation to induce stress on the metal component being calibrated. The axial forces generated within the metal component by rotation, opposed by the reaction arm, results in tension which is calibrated by a piston driven load cell secured directly to the transducer. Display devices attached to the transducer and load cell simultaneously and contemporaneously show the calibrated results.

The present subject matter discloses a method of measuring a peak load, including the steps of placing an indenter between a first surface and a second surface, exerting a load on at least one of the first and second surfaces, measuring at least one of a width, depth, radial chord length, and cross-sectional area of an indentation formed by the indenter in at least one of the first and second surfaces; and converting the measured parameter into a load value. Certain methods further include the steps of converting the measured parameter into a load per length value and obtaining a load value by integrating along a circumferential length of the indentation. In still other methods, the exerted load is a compressive load.

A three-dimensional rib for a crash test dummy includes at least two layers of a band material and a layer of damping material sandwiched in between the at least two layers of the band material.

There is provided a bolt sensor which detects a fastened state of a bolt. The bolt sensor includes a sensor body including a through hole into which a shaft of the bolt is to be inserted, a light guide extending along an outer periphery of the sensor body, and a light source configured to emit light to the light guide based on output of the sensor body.