Abstract: In an aspect a device for a driven shaft is provided that receives an input torque that varies cyclically between a peak input torque and a low input torque at a peak input torque frequency, which includes a shaft adapter, a rotary drive member, at least one isolation member, a torsional vibration damping structure including an inertia member and a elastomeric damping member, and a supplemental damping structure. The supplemental damping structure applies a supplemental damping torque to resist relative movement between the rotary drive member and the inertia member in addition to damping provided by the elastomeric damping member. A sum of torques including the supplemental damping torque limits a maximum twist between a first end of the driven shaft and a second end of the driven shaft, to below a yield point of the driven shaft.

Abstract: In one aspect, there is provided an isolation device, which includes a hub, a pulley and at least one isolation spring arrangement including first and second springs in series. The first spring rate is higher than the second spring rate. Initially during torque transfer from the first one to a second one of the hub and the pulley, the entire first isolation spring is slid along a friction surface towards the second one of the hub and the pulley during compression of the second isolation spring thereby generating a first frictional damping torque. During torque transfer the other way, at least a portion of the first isolation spring remains stationary relative to the friction surface, such that the first frictional damping torque is greater than the second frictional damping torque.

Abstract: In an aspect a device for a driven shaft is provided that receives an input torque that varies cyclically between a peak input torque and a low input torque at a peak input torque frequency, which includes a shaft adapter, a rotary drive member, at least one isolation member, a torsional vibration damping structure including an inertia member and a elastomeric damping member, and a supplemental damping structure. The supplemental damping structure applies a supplemental damping torque to resist relative movement between the rotary drive member and the inertia member in addition to damping provided by the elastomeric damping member. A sum of torques including the supplemental damping torque limits a maximum twist between a first end of the driven shaft and a second end of the driven shaft, to below a yield point of the driven shaft.