When transmitting torque from a drive shaft to a driven shaft, flexible couplings:
• absorb and dampen irregularities in the torque,
• distribute peak loads,
• allow misalignments and offsets between the shafts,
• permit some distortions in the mounting beds,
• avoid the unwelcome constraints that may occur if a rigid coupling were fitted in the same condition.
• allow a lighter construction, with wider tolerances, and lower cost.
In particular, a flexible coupling is absolutely essential if the machines that are coupled are on
flexible mountings.
Moreover, there is no play in a flexible coupling, and it therefore runs silently, without friction
and does not need to be greased.