Airbus Operations (s.a.s.)

Airbus Operations Gmbh

Simon Dols

Patricia Morgue

Manuel Paredes

Clément Chirol

Sophie Gourdon

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.

Method and device for monitoring the clamping of an assembly by a threaded fastener

A method of monitoring the clamping of an assembly by a threaded fastener. One element of the threaded fastener is rotated by a driver while the other is held stationary by a holding tool. The screwing torque and reaction torque of the holding tool are measured. Analyzing their evolution as a function of a third parameter makes it possible to determine accurately the pre-tension in the assembly. The disclosure herein further relates to a clamping method employing a real-time monitoring method of this kind. The disclosure herein also relates to a corresponding device for implementing a method of this kind.

A process for checking when tightening a threaded fastener that it has been tightened on the complete threads of the fastener. In order to do this the process comprises detecting different gradients in a tightening graph representing torque as a function of another parameter and comparing each gradient with predetermined values. According to the portions of graph detected and their gradient values it is possible to determine whether tightening is correct and has taken place on the complete threads of the fastener, or if not it is possible to identify a cause of failure.

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Toulouse, France

Simon Dols