Shaft Coupling

 Shafts are usually available up to 7 metres length due to inconvenience in transport. In order to have a greater length, it becomes necessary to join two or more pieces of the shaft by means of a coupling.

 Shaft couplings are used in machinery for several purposes, the most common of which are the following : 

ü  To provide for the connection of shafts of units that are manufactured separately such as a motor and generator and to provide for disconnection for repairs or alternations.

ü  To provide for misalignment of the shafts or to introduce mechanical flexibility.

ü  To reduce the transmission of shock loads from one shaft to another.

ü  To introduce protection against overloads.

ü  It should have no projecting parts.

 Shaft couplings are divided into two main groups as follows:

1. Rigid coupling.

 It is used to connect two shafts which are perfectly aligned. Following types of rigid coupling are important from the subject point of view: 

·         Sleeve or muff coupling.

·         Clamp or split-muff or compression coupling, and

·         Flange coupling.

2. Flexible coupling. 

It is used to connect two shafts having both lateral and angular misalignment. Following types of flexible coupling are important from the subject point of view : 

·         Bushed pin type coupling,

·         Universal coupling, and

·         Oldham coupling.