ISOLATING DECOUPLER

An isolating decoupler comprising a shaft having an outer surface, a pulley rotationally engaged about the shaft, a torsion spring having first and second sections with major and minor diameters, the torsion spring engaging the pulley, a wrap spring having an inner diameter less than an outer surface outer diameter, the wrap spring frictionally engaging the outer surface, the torsion spring having an end fixedly connected to the wrap spring, the torsion spring loaded in a winding direction whereby the diameter of each coil of the torsion spring decreases in a progressive sequence as a load increases, the second section is disposed radially outboard of the wrap spring such that the second section moves radially inward to clamp the wrap spring during a load condition, and the pulley comprising a member disposed to progressively release the wrap spring from the shaft outer surface upon occurrence of a predetermined load condition.