CARGO HOOK WITH WEIGHING SCALE

摘要

A cargo hook having fore and aft trunnions mounted in fore and aft bearings supported on frame members of a helicopter or the like, is provided with strain gauges secured in a bore in the aft trunnion for measuring shear strain on the trunnion by a load supported by the cargo hook. Additional strain gauges are secured in the aft trunnion bore for measuring axial and Poisson forces on the trunnion as the axis through the fore and aft trunnions varies from horizontal. The strain gauges are included in an electric circuit of a Wheatstone bridge and an indicator which converts the electric signals from the strain gauges to a readout of units of load weight. The strain gauges which measure axial and Poisson forces are connected in the electric circuit to compensate for the deviation from horizontal of the axis through the fore and aft trunnions, to provide an accurate readout of load weight applied to the cargo hook. A low RF impedence ring is mounted in the trunnion bore to protect against electromagnetic inteference, and a passageway in the trunnion for leading electrical conductors from the strain gauges outwardly of the trunnion, is filled with a sealant for protecting the strain gauges against environmental contaminants such as dust and moisture.