Couplings are mechanical devices used to connect together two shafts to transmit power. Coupling can have many functions, but their primary purpose is to connect shafts of units that are manufactured separately and rotating such as motor and generator. They, however, do permit some end movement or misalignment for flexibility and also provide easy disconnection of the two separate devices for repairs or modifications. They also reduce the shock that is transmitted from one shaft to another, protect against overloads and can alter the amount of vibration a rotating unit experiences.
There are many various types of couplings in the industry today. The two most common ones are the rigid and flexible couplings. A rigid coupling has all the functions of a regular coupling alongside with some additional advantages. Using rigid couplings allow for more accurate alignment and a secure hold. With this precise alignment and firm hold, rigid couplings are able to maximize the performance of a machine. Rigid couplings further have two basic types of designs; the sleeve-style and clamped or compression styles couplings. Sleeve-style couplings are basically tubes that have an inner diameter that is the same as the size of the shafts. They can be easily slipped over the shaft and screws can be tightened into it to secure the shaft inside the coupling and ensure that the shaft does not pass all the way through it. The clamped couplings come in two separate parts that can be fitted together onto a shaft. These couplings allow more flexibility as they can be fitted onto shafts that are fixed in place.
Flexible coupling also work on the basics of holding two shafts together, however they allow more flexibility of the shafts. They are used to transmit torque if the shafts happen to be misaligned. They can accommodate 3 degrees up to misalignment. They can even accommodate parallel misalignment. Both the types of couplings have their own advantages depending on their application.