InUse – Intelligent Ring Washer for Measurements of Forces in Screw Connections

Abstract

Releasable connections between mechanical components inside machinery are mainly accomplished with screws. The necessary clamping forces to achieve a sufficient connection are produced by an applied torque. To calculate the applied torque according to the required forces, the friction coefficient within the screw needs to be taken into account, which can only be conditionally determined. Therefore, in critical machine components the employed screws are commonly over-dimensioned to increase safety. The herein presented device comprises a force-measuring washer with an onboard RFID tag for passive and wireless data transmission. In this way, the safety of the connection can be enhanced by accurately measuring the force and adjusting the applied torque accordingly.