Couplings

A flexible coupling exists to transmit power (torque) from one shaft to another; to compensate for minor amounts of misalignment; and, in certain cases, to provide protective functions such as vibration dampening or acting as a “fuse” in the case of torque overloads
However, it is a flexible type of coupling and can be used for non-collinear shafts. Gear couplings accommodate angular misalignment of about 2 degrees and parallel misalignment of 0.25…0.5 mm.
Flexible couplings can accommodate some misalignment but should not be used as an excuse for poor alignment or lack of maintenance. Misalignment of flexible couplings can lead to excessive force on either the motor or the driven load. This can lead to failure of other components or large amounts of vibration.
Flexible couplings are usually used to transmit torque from one shaft to another when the two shafts are slightly misaligned. They can accommodate varying degrees of misalignment up to 1.5° and some parallel misalignment. They can also be used for vibration damping or noise reduction

A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. The primary purpose of couplings is to join two pieces of rotating equipment while permitting some degree of misalignment or end movement or both. In a more general context, a coupling can also be a mechanical device that serves to connect the ends of adjacent parts or objects.^[1] Couplings do not normally allow disconnection of shafts during operation, however there are torque-limiting couplings which can slip or disconnect when some torque limit is exceeded. Selection, installation and maintenance of couplings can lead to reduced maintenance time and maintenance cost.