VEHICLE SEAT SENSOR HAVING SELF-MAINTAINING AIR BLADDER

摘要

A hydrostatic weight sensor element incorporates a volume restorer for restoring the volume thereof when the applied load is removed therefrom, whereupon a check valve in fluid communication therewith admits sensing fluid thereinto if the pressure of the sensing fluid within the hydrostatic weight sensor element is less than local atmospheric pressure, so as to replenish lost sensing fluid. The volume restorer may comprise either the seat cushion, operatively coupled to the load bearing surfaces of the hydrostatic weight sensor element, or an elastic medium incorporated within the hydrostatic weight sensor element, whereby the volume restorer is adapted so that the restored volume of fluid is less than the volume capacity of the hydrostatic weight sensor element. A pressure relief valve is provided for releasing sensing fluid so as to prevent damage from overload conditions.