In the present disclosure, embodiments including a system, device and methods are disclosed for accurately measuring the strain or extension of a fastener that occurs as the nut on the fastener is tightened and the fastener is put under load. The measurement technique is based on measurement of the time for an ultrasonic wave generated on one end of the fastener to travel a round trip through the fastener. As the fastener is tightened, the applied stress causes an associated increase in length. This length can be determined from a measurement of the increase in transit time. In various embodiments, the disclosed device and method uses laser ultrasonic testing (LUT), in which a pulsed laser generates the ultrasonic wave and a type of laser vibrometer detects the wave when it returns to the position of generation following a combination of longitudinal wave reflections and a mode conversion to a shear wave.

A method for checking the tightening tension of at least one fastening bolt for fastening at least two aeronautical parts, wherein it includes the steps consisting in mounting a centring device on a head of a screw of the bolt, the centring device including an aperture aligned with an axis of the screw; engaging one end of a sensor in the aperture of the device until this end is in contact with the head of the screw; checking at least one physical parameter of the bolt by the sensor, this parameter being representative of the tightening tension of the bolt; then removing the centring device.

A test bench for screwdrivers comprises a hydraulic brake unit (11) provided with a coupling (12) for a screwdriver to be tested and angle and torque measurement transducers (15). The brake unit (11) comprises a disk (40) axially connected to the coupling (12) so as to be rotated by a screwdriver to be tested, and braking plates (42, 43) pushed in a controllable manner with their braking surfaces (44, 45) against the disk (40) by means of a plurality of pistons (46, 47) supplied with fluid by an electrovalve (16). The pistons (46, 47) of the plurality can be selectively activated under the control of the control unit (26) so as to select a maximum braking torque of the brake. The control may be performed by means a PID controller (19) which receives an electrovalve control signal (22) from a control unit (26) so as to follow braking curves depending on the angle of rotation and/or torque measured and has parameters which can be set using different sets of parameters. A method for controlling the bench is also described.

A test bench for screwdrivers comprises a hydraulic brake unit (11) provided with a coupling (12) for a screwdriver to be tested and angle and torque measurement transducers (15). The brake unit (11) comprises a disk (40) axially connected to the coupling (12) so as to be rotated by a screwdriver to be tested, and braking plates (42, 43) pushed in a controllable manner with their braking surfaces (44, 45) against the disk (40) by means of a plurality of pistons (46, 47) supplied with fluid by an electrovalve (16). The pistons (46, 47) of the plurality can be selectively activated under the control of the control unit (26) so as to select a maximum braking torque of the brake. The control may be performed by means a PID controller (19) which receives an electrovalve control signal (22) from a control unit (26) so as to follow braking curves depending on the angle of rotation and/or torque measured and has parameters which can be set using different sets of parameters. A method for controlling the bench is also described.

An electrode joining apparatus for joining a free electrode to a fixed electrode, the fixed electrode having a top end. The apparatus can include an electrode holder configured to selectively hold the fixed electrode. A torque device can be positioned above the electrode holder, the torque device configured to grip and spin the free electrode to join the free electrode to the fixed electrode. A blowout jet can be oriented to selectively force a stream of gas toward the top end of the fixed electrode when the fixed electrode is held by the electrode holder. As such, the blowout jet can help remove dust, debris, or graphite residue on the top end of the fixed electrode before joining of the free electrode to the fixed electrode. The fixed electrode can include a threaded socket, the blow jet oriented to force the stream of gas toward the threaded socket.

A transmission (3) for an electric miniature drive or microdrive, having a transmission housing (9), an attachment flange (13) for attaching the transmission (3) to an application or load, a driven shaft (7), supported in at least one driven bearing (8), for driving the application. The driven shaft (7) is connectable via the transmission mechanism to the miniature drive or microdrive, and a torque measuring member (15) for the registration of the torque generated on the driven shaft (7) using a flexible element during operation of the miniature drive or microdrive. A magnetic encoder system (19) is disposed on the flexible element (17), which has a magnetic field measuring element (25) for measuring a rotatory displacement of the flexible element (17). The flexible element (17) is disposed axially between the transmission mechanism and the attachment flange (13).

A transmission (3) for an electric miniature drive or microdrive, having a transmission housing (9), an attachment flange (13) for attaching the transmission (3) to an application or load, a driven shaft (7), supported in at least one driven bearing (8), for driving the application. The driven shaft (7) is connectable via the transmission mechanism to the miniature drive or microdrive, and a torque measuring member (15) for the registration of the torque generated on the driven shaft (7) using a flexible element during operation of the miniature drive or microdrive. A magnetic encoder system (19) is disposed on the flexible element (17), which has a magnetic field measuring element (25) for measuring a rotatory displacement of the flexible element (17). The flexible element (17) is disposed axially between the transmission mechanism and the attachment flange (13).

A wheel nut engagement checking system for a vehicle delivered by a conveyor includes: a moving member disposed at one side of the conveyor; a wheel lifting apparatus disposed on the moving member, and lifting a wheel of the vehicle from the conveyor to a predetermined height; a wheel nut torque checking apparatus provided on an arm of a robot disposed on the moving member, engaging a nut runner to a wheel nut of the wheel, and checking an engage torque of the wheel nut by rotating the nut runner; and a controller controlling a speed of the moving member, lifting the wheel to the predetermined height using the wheel lifting apparatus, moving the wheel nut torque checking apparatus using the robot so as to engage the nut runner to the wheel nut, and detecting an engage torque of the wheel nut by rotating the nut runner.

A wheel nut engagement checking system for a vehicle delivered by a conveyor includes: a moving member disposed at one side of the conveyor; a wheel lifting apparatus disposed on the moving member, and lifting a wheel of the vehicle from the conveyor to a predetermined height; a wheel nut torque checking apparatus provided on an arm of a robot disposed on the moving member, engaging a nut runner to a wheel nut of the wheel, and checking an engage torque of the wheel nut by rotating the nut runner; and a controller controlling a speed of the moving member, lifting the wheel to the predetermined height using the wheel lifting apparatus, moving the wheel nut torque checking apparatus using the robot so as to engage the nut runner to the wheel nut, and detecting an engage torque of the wheel nut by rotating the nut runner.

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.