Patent ID: 7299702

Claim:
A device for monitoring the operation of an airplane control surface, the control surface being mounted on at least two arms each hinged about an axis on a portion of an airfoil, at least one of the two arms being mounted on the associated airfoil by a hinge that comprises at least one pivot, at least one U-bolt having at least two limbs with orifices in alignment on said axis for passing the pivot, and a captive member having an orifice for passing the pivot and having a limited range of displacement between the limbs of the U-bolt along the axis, the pivot possessing a cylindrical body, a head of cross-section that is not circularly symmetrical so as to enable it to co-operate with a driver tool for turning it, and a threaded end opposite from the head, the device being characterized in that: the pivot is constituted by a dynamometric pin comprising a body ( 10 ) of circularly cylindrical shape, a head ( 12 ) of cross-section that is not circularly symmetrical so as to enable it to co-operate with a driver tool for turning it, and a threaded end ( 14 ) opposite from the head ( 12 ), the body ( 10 ) of the pin having at least one peripheral set-back groove ( 16 ); the body ( 10 ) of the pin has a cavity that opens out at one end of the body, that reaches at least the level of the set-back groove ( 16 ), and that contains at least one force-sensing element ( 18 ) disposed against the wall of the cavity level with the set-back groove ( 16 ), the opening of the cavity which opens out at one end of the body being closed in weatherproof manner while allowing wires connected at least to the force-sensing element ( 18 ) to pass through; the head ( 12 ) and a nut screwed onto the threaded end are in direct or indirect contact with the limbs of the U-bolt, such that the groove ( 16 ) in the body of the pin overlies the interface between one of the limbs of the U-bolt and the adjacent portion of the captive member; the size of the displacement range of the captive member between the limbs of the U-bolt, and the width of the groove ( 16 ), presenting a relationship such that one edge of the groove ( 16 ) is located within the limb and the other edge is located within the captive member; the head ( 12 ) has an angular position such that at least the sensing element is sensitive to forces acting across the length of the pin; and the device further includes a signal processor circuit using at least one signal from at least one sensing element ( 18 ) of the pin to determine at least whether the control surface is present.