Patent ID: 6178829
Filing Date: 2001-01-30
Classification: B64C,F16C,G01L,Y02T

Abstract:
A fail-safe redundant linkage and sensor assembly comprising:a first elongated metal tube having a predetermined inner and outer diameter;a second shorter elongated metal tube having an inner diameter which is slightly greater than the outer diameter of said first tube, and said first tube extending into said second tube;a hollow cylindrical spring having two ends and having relatively low deflection per unit of applied force, one end of said second tube being mechanically secured to one end of said spring, and the other end of said spring being mechanically secured to an intermediate location along the length of said first tube, with said first tube extending through said cylindrical spring and into said second tube to a point near the end of said second larger tube, whereby, as force is applied to said linkage, the relative longitudinal position of said first and second tubes at said point will shift;a position sensor assembly connected between said two tubes near said point to provide an output which varies in accordance with the relative displacement of said tubes and in accordance with the force applied to said linkage, said sensor assembly being redundantly mechanically secured to said first tube, both by welding and by a transverse fastener;a stop assembly mounted in the end of the second tube away from said spring and near said point, said stop assembly having an inwardly extending web;said sensor assembly including positive and negative stop surfaces on opposite sides of said web, and spaced from said web by a relatively small distance corresponding to a normal range of said sensor; andwhereby under normal conditions forces applied to said linkage shift the relative position of said first and second tubes and provide a variable output from said sensor, and in the event of excessive load application the spring is protected from overstressing, and in the event of the mechanical failure of any one mechanical interconnection, the linkage will still be operative.