A decoupler for transferring a drive torque from a rotary drive to a rotary output, comprising: - a drive part arranged in the drive torque flow on the rotary drive side, - an output part arranged in the drive torque flow on the rotary output side, - a series connection which consists of a helical torsion spring and a one-way clutch, arranged in the drive torque flow between the drive part and the output part, which permits an overrunning of the output part with respect to the drive part in the drive direction of rotation, - a first spring seat, arranged in the drive torque flow on the drive part side, for the first end of the helical torsion spring - and a second spring seat, arranged in the drive torque flow on the output part side, for the second end of the helical torsion spring, wherein the spring seats (14, 15) increase axially in the manner of ramps and wherein the helical torsion spring ends (12, 13) bearing there against radially expand the helical torsion spring while transferring the drive torque, characterised in that the helical torsion spring ends (12, 13) and the spring seats (14, 15) have reciprocal rotary stops (19, 20), which each, in the drive direction of rotation, prevent a relative torsion of the second spring seat relative to the second helical torsion spring end and of the first helical torsion spring end relative to the first spring seat such that, when the one-way clutch is open, a torque entraining the helical torsion spring is transferred on the output side from the rotary stop of the second spring seat to the rotary stop of the second helical torsion spring end and is transferred on the drive side from the rotary stop of the first helical torsion spring end to the rotary stop of the first spring seat. - a drive part arranged in the drive torque flow on the rotary drive side, - an output part arranged in the drive torque flow on the rotary output side, - a series connection which consists of a helical torsion spring and a one-way clutch, arranged in the drive torque flow between the drive part and the output part, which permits an overrunning of the output part with respect to the drive part in the drive direction of rotation, - a first spring seat, arranged in the drive torque flow on the drive part side, for the first end of the helical torsion spring - and a second spring seat, arranged in the drive torque flow on the output part side, for the second end of the helical torsion spring, wherein the spring seats (14, 15) increase axially in the manner of ramps and wherein the helical torsion spring ends (12, 13) bearing there against radially expand the helical torsion spring while transferring the drive torque, characterised in that the helical torsion spring ends (12, 13) and the spring seats (14, 15) have reciprocal rotary stops (19, 20), which each, in the drive direction of rotation, prevent a relative torsion of the second spring seat relative to the second helical torsion spring end and of the first helical torsion spring end relative to the first spring seat such that, when the one-way clutch is open, a torque entraining the helical torsion spring is transferred on the output side from the rotary stop of the second spring seat to the rotary stop of the second helical torsion spring end and is transferred on the drive side from the rotary stop of the first helical torsion spring end to the rotary stop of the first spring seat.