According to the present invention, an axial force of a screw which is generated by screw driving is estimated. A control part applies a predetermined torque generated by a rotation axis servomotor to a screw in a rotation direction where a screw is driven, and thereafter releases the torque. The control part then estimates an axial force of the driven screw based on fluctuation of a rotation position of the rotation axis servomotor which occurs due to the release of the torque.

A method and apparatus for tightening a screw connection having a motor-operated screwdriver unit, wherein the angle of rotation and the torque are determined during the tightening to be able to stop the tightening process on reaching a desired tightening tension. An increase in the torque over the angle of rotation is determined by a determination device in a first tightening region and a change in the increase in the torque over the angle of rotation is determined in a second, following tightening region, with the screwdriver unit being stopped by a control device on reaching or exceeding of a maximum permitted change in the increase and/or of a change speed that is determined with reference to the increase that occurred in the first tightening region.

An automatic screw tightening method includes measuring a datum on time-varying screw tightening torque from a motor and a datum on time-varying motor rotational speed between a screw tightening start time point for a male thread with respect to a female threaded hole and a screw tightening completion time point; extracting a plurality of features from measurement-based data on the time-varying screw tightening torque and the time-varying motor rotational speed; and determining, with use of the features, whether a tightened state of the male thread is fit or unfit. In the determination, determining a unified numerical index from the features is included, and the numerical index is compared with a predetermined threshold in the determination of whether the tightened state is fit or unfit. The numerical index is a Taguchi (T) method-based overall evaluation measure from the features.

A method and a device are provided for simplifying a flow-hole screw process, in which the difference between a process parameter and its smoothed value is employed as a criterion for changing said process parameter or another process parameter in order in particular to be able to determine the changeover point between hole forming and thread forming.

A setting torque tool to tighten a screw or a similar fastener to a target torque is disclosed. The torque tool comprises a main body with a housing and a drive shaft, which is firmly attached to the housing to transfer a torque. The drive shaft has a connection area, to which a drive can be connected. An adapter for an operating tool rotates together with the housing and the drive shaft to transfer the torque, Sensor measure and evaluate the torque transferred. A release mechanism, which is arranged in the housing, releases the torque tool upon reaching a target torque.

A device for monitoring clamping of an assembly including at least one part to be clamped, an internally threaded element and an externally threaded element engaged in an internal thread of the internally threaded element. The device includes a driver to rotate one of the elements including the internally threaded element and the externally threaded element to clamp the assembly and a first sensor to measure a screwing torque of the driver, a tool for holding fixed against rotation the other of the elements including the internally threaded element and the externally threaded element, a second sensor to measure a reaction torque of the holding tool, a mechanism for determining a third parameter chosen from a time elapsed from a given time and a screwing angle from a reference position, and a calculation system to determine pre-tension in the externally threaded element.

A device for lifting and tightening screws includes a transporting unit to move the device to a screw suction position or a screw locking position, a suction nozzle unit, a vacuum generator, and an electronic screwdriver unit. When the device is moved to a position to attract and apply suction to a screw, the suction nozzle unit captures a screw. When the device is moved to the screw locking position, the electronic screwdriver unit tightens the screw. The device prevents the suction nozzle from contacting the workpiece, guides a suction position of the screw, and can function in relation to screw holes surrounded by steps and barriers.

A fastening system for fastening a fastener to a workpiece, includes a movable carriage on which the workpiece is placed, a coordinate detection unit configured to detect a position of the fastener temporarily tightened onto the workpiece as coordinates in a coordinate system of the movable carriage, a storage device configured to store the coordinates detected by the coordinate detection unit, and a retightening device configured to determine a position of the fastener based on the coordinates stored in the storage device and retighten the fastener that is at the determined position.

The present invention relates to an operation parameter regulation unit (50) for use with a bolting system having a plurality of networked electrically powered torque tools (10, 11) and/or drive portions of torque tools (10, 11) for simultaneous tightening of industrial threaded fasteners (40), the operation parameter regulation unit (50) including: a processing unit (53); an output unit (51) connected and/or integrated with the processing unit (53); an input unit (52) connected and/or integrated with the processing unit (53); an activation unit (55) connected and/or integrated with the processing unit (53) for activating operation units of the plurality of networked electrically powered torque tools (10, 11) and/or drive portions of torque tools (10, 11); and a control unit (54) for controlling operation parameters (41) of each of the plurality of networked electrically powered torque tools (10, 11) and/or drive portions of torque tools (10, 11) to maintain a difference between the operation parameters (41) within a predetermined value.

A fastening device for fastening a bolt to a fastening target object, wherein the bolt has a bolt head female screw section in an inner circumferential surface of a recess provided in an upper surface of a bolt head section. The fastening device includes a tension rod having a rod male screw section engaging the bolt head female screw section; a drive socket circumferentially surrounding the tension rod and having a lower end section with a grasper for laterally grasping the bolt head section; a supporter circumferentially surrounding the drive socket and having a lower end section protruding downward beyond a lower end section of the drive socket; a sensor for sensing compression force acting on the supporter in the upward/downward direction; a first motor for rotating the tension rod around an axis extending in the upward/downward direction; and a second motor for rotating the drive socket around the axis.