industry. These names include flexible coupling, flexible beam coupling, flexible shaft coupling, flexure, helical coupling, and shaft coupling. The primary benefit to using a flexible beam coupling to join two rotating shafts is to reducing vibration and reaction loads which in turn will reduce overall wear and tear on machinery and prolong equipment life. Bush pin flange Bush pin flange coupling is used for slightly imperfect alignment of the two shafts. This is modified form of the protected type flange coupling. This type of coupling has pins and it works with coupling bolts. The rubber or leather bushes are used over the pins. The coupling has two halves dissimilar in construction. The pins are rigidly fastened by nuts to one of the flange and kept loose on the other flange. This coupling is used to connect shafts which have a small parallel misalignment, angular misalignment or axial misalignment. In this coupling the rubber bushing absorbs shocks and vibration during its operations. This type of coupling is mostly used to couple electric motors and machines. Constant velocity There are various types of constant-velocity (CV) couplings: Rzeppa joint, Double cardan joint, and Thompson coupling. Clamp or split-muff In this coupling, the muff or sleeve is made into two halves parts of the cast iron and they are joined by means of mild steel studs or bolts. The advantages of this coupling is that assembling or disassembling of the coupling is possible without changing the position of the shaft. This coupling is used for heavy power transmission at moderate speed. Diaphragm Diaphragm couplings transmit torque from the outside diameter of a flexible plate to the inside diameter, across the spool or spacer piece, and then from inside to outside diameter. The deforming of a plate or series of plates from I.D. to O.D accomplishes the misalignment. Disc Disc couplings transmit torque from a driving to a driven bolt tangentially on a common bolt circle. Torque is transmitted between the bolts through a series of thin, stainless steel discs assembled in a pack. Misalignment is accomplished by deforming of the material between the bolts. Elastic An elastic coupling transmits torque or other load by means of an elastic component. One example is the coupling used to join a windsurfing rig (sail, mast, and components) to the sailboard. In windsurfing terminology it is usually called a "universal joint", but modern designs are usually based on