A screw fastening method includes reversely rotating a shaft part of a fastening tool in a direction of loosening one of an external thread and an internal thread, which is engaged with the shaft part, while one of the external thread in a non-screwed state and the internal thread in a non-screwed state, which is engaged with the shaft part, is pressed against the other thread, detecting collisions between thread ridges of the external thread and the internal thread using a sensor while the shaft part remains rotated reversely, determining whether or not a time interval between collisions detected by the sensor matches a theoretical cycle of collisions calculated from rotation speed of the shaft part, and fastening the external thread and the internal thread to each other by normally rotating the shaft part when it is determined that the time interval matches the theoretical cycle.

A more reliable and fool-proof method and apparatus for assembling an article of assembly (e.g. with predetermined screw torque requirements) in which the article of assembly has multiple fastening locations. The method comprises holding the article of assembly fixed while providing at least two different types of targets fixed relative to the article of assembly that correspond to the individual fastening locations. Fasteners are fastened into the article of assembly at the fastening locations. When fastening is occurring at one of the fastening locations, one of the targets is being sensed. Based on the target sensed, a target output is generated that differentiates between different types of targets thereby indicating fastening location of the fastening tool. The electronic target output is used for electronic control such as for stopping a conveyor to keep the article of assembly at an assembly station until the fastening operations have been completed.

A more reliable and fool-proof method and apparatus for assembling an article of assembly (e.g. with predetermined screw torque requirements) in which the article of assembly has multiple fastening locations. The method comprises holding the article of assembly fixed while providing at least two different types of targets fixed relative to the article of assembly that correspond to the individual fastening locations. Fasteners are fastened into the article of assembly at the fastening locations. When fastening is occurring at one of the fastening locations, one of the targets is being sensed. Based on the target sensed, a target output is generated that differentiates between different types of targets thereby indicating fastening location of the fastening tool. The electronic target output is used for electronic control such as for stopping a conveyor to keep the article of assembly at an assembly station until the fastening operations have been completed.

A screw fastening method includes reversely rotating a shaft part of a fastening tool in a direction of loosening one of an external thread and an internal thread, which is engaged with the shaft part, while one of the external thread in a non-screwed state and the internal thread in a non-screwed state, which is engaged with the shaft part, is pressed against the other thread, detecting collisions between thread ridges of the external thread and the internal thread using a sensor while the shaft part remains rotated reversely, determining whether or not a time interval between collisions detected by the sensor matches a theoretical cycle of collisions calculated from rotation speed of the shaft part, and fastening the external thread and the internal thread to each other by normally rotating the shaft part when it is determined that the time interval matches the theoretical cycle.

The invention relates to a pneumatic needling device for the local surface treatment, more particularly fastening, of components, comprising a first and a second needle (2) that can move in a needle direction; a first and a second piston chamber (3) for applying pneumatic pressure to the first and second needles in the needle direction; a pressure supply (1) that can be connected to and disconnected from the piston chambers, more particularly as a result of a movement of the needles in the needling device; a pressure recording means (5) for measuring pressure fluctuations in the piston chambers; and a control means (6) designed to carry out a reaction on the basis of the measured pressure fluctuations.

Methods and apparatus for evaluating characteristics of components of a mechanically attached connection are disclosed. Characteristics that may be evaluated include, but are not limited to, the position of a conduit gripping device on a conduit, an amount of axial compression or stroke of the conduit gripping device, and an amount of clamping force applied to the conduit gripping device as the conduit gripping device is axially compressed or stroked.