Mechanical Couplings 

What is Coupling?

A coupling is a device or linkage which allows the transmission of motion, force, and torque between two components or systems.

Why Mechanical Couplings are used?

Usually mechanical coupling is used to transmit torque between the driving and driven shafts. One end of the coupling is connected to the driving shaft and the other end is connected to the driven shaft.

These mechanical couplings are used in manufacturing industries such as aerospace, automotive, textile, and many more.

Types of Mechanical Couplings

  • Muff or Sleeve Coupling
  • Split-Muff Coupling
  • Oldham Coupling
  • Flange Coupling
  • Flexible Coupling
  • Gear Coupling
  • Universal Coupling
  • Fluid Coupling

1-Muff or Sleeve Coupling:

Muff or Sleeve Coupling

It is a simple type of coupling. It consists of a simple hollow cylindrical part which is called a sleeve. It is used to join two inline shafts of the same diameter. The hole of the sleeve is the size of the shaft. A muff or Sleeve Coupling is fitted over the two shaft ends. Two threaded holes are provided where the screws are tightened to eliminate the longitudinal motion so that the shaft remains in position.

2-Split Muff Coupling:

Split Muff Coupling 

Split Muff Coupling the Cylindrical sleeve is splinted into two parts upper and lower hemi cylinders. Two, four, six, or eight wholes are available where the bolts and struts are tightened to connect the upper and lower hemi cylinders. The main advantage of the Split Muff Coupling over the Sleeve Coupling is that there is no need to change the position of the shaft while coupling.

3-Oldham Coupling:

Oldham Coupling

Oldham Coupling consists of three parts. Two are the lightweight hubs and the third is the disk between them. The tenons on the hubs are mate with the slots in the disk. Both hubs are connected to the shaft ends and the disk is placed between them which is slightly pressed by both shafts. The main advantage of the Oldham Coupling is to transmit the torque between the two misaligned shafts.

4-Flange Coupling:

Flange Coupling 

Flange Couplings are used to connect the two aligned hollow or solid shafts. It consists of two flanges that have the same number of threaded holes. Both Flanges are mounted on the ends of the shaft and blots and nuts are tightened in the holes. Usually, a gas kit is placed between the two flanges to eliminate the leakage. They are used for both medium and heavy-duty applications. A tapper key is used to ensure the no-slip condition.

5-Flexible Coupling:

Flexible Coupling 

Flexible Coupling is the same as Flange Coupling but the difference is that the rubber bushing with nuts and bolts which absorbs the shocks and vibrations between the two shafts on which the coupling is mounted. It is used for medium-duty applications.

6-Gear Coupling:

Gear Coupling

Gear Coupling is the subcategory of Flange Coupling. Typical Gear Coupling consists of two joints - fixed on each shaft and the spindle is mounted on both sleeves. 

7-Universal Coupling:

Universal Coupling 

Universal Coupling is used when shafts are at some angle. The angle between the shafts can be constant or it may change to some extent. The most important application of Universal is the automobile where the shaft is connected from the gearbox to the axle.

8-Fluid Coupling:

Fluid Coupling

Fluid Coupling is used to transmit torque where the variable speed operation and without shock loading transmitting system is required. Here the pump side of the Fluid Coupling is connected to the one shaft and the turbine side is connected to the second shaft. As time passes the speed of both shafts matches. A critical example of Fluid Coupling is the clutch system in automobiles.