Recirculating ball or roller mechanism e.g. for use in aircraft has position sensor on safety nut to detect abnormal displacement

摘要

The mechanism, comprising a screw (1) rotating in a primary nut (2) with balls or rollers between their threads, and a safety nut (10) connected to the primary nut by shearing pins to ensure a friction coupling in the event of primary nut failure, has position sensors (C1, C2) on the safety nut or safety connectors (4, 5) to detect any abormal displacement between the primary and safety components. The position sensors can be in the form of induction magnets or linear variable differential transformers located in the safety nut to monitor the play between threads, or between journals (13) on the safety nut and connectors (4, 5).