ISOLATING DECOUPLER

An isolating decoupler comprising a shaft, a pulley having an inner surface, a pulley rotationally engaged about the shaft, a torsion spring having a first section having a major diameter and a second section having a minor diameter, the major diameter is greater than the minor diameter, the torsion spring engaged with the shaft, a wrap spring having an outer diameter greater than an inner surface diameter, the wrap spring frictionally engaging the inner surface, the wrap spring loaded in an unwinding direction, the torsion spring having an end fixedly connected to the wrap spring, the torsion spring loaded in an unwinding direction whereby the diameter of each coil of the torsion spring decreases in a progressive sequence as a load increases, the first section is disposed radially inboard of the wrap spring such that the first section moves radially outward to clamp the wrap spring during a load condition.