A coupling is a device used for connecting two shafts collectively at their ends for the purpose of transmitting power.
Couplings do not normally allow disconnection of shafts during operation, however right now there are torque limiting couplings which can slip or disconnect when some torque limit is exceeded.
The primary purpose of couplings is to become listed on two pieces of rotating equipment while permitting some degree of misalignment or end movement or both.
By careful selection, installation and maintenance of couplings, substantial financial savings can be made in decreased maintenance costs and downtime.
3 main types of couplings:
1. Rigid coupling a rigid coupling is normally a unit of equipment used to become listed on two shafts within a engine or mechanical program. It might be used to connect two separate systems, like a electric motor and a generator, or even to restoration a connection within a single system. A rigid coupling can also be added between shafts to lessen shock and wear at the stage where the shafts meet.
When joining shafts within a machine, mechanics can choose between flexible and rigid couplings. While flexible units offer some movement and give between your shafts, rigid couplings will be the most reliable choice for exact alignment and protected hold. By specifically aligning the two shafts and keeping them firmly in place, rigid couplings help to maximize performance and increase the expected life of the machine. These rigid couplings can be found in two basic designs to fit the needs of different applications. Sleeve-style couplings are the most affordable and easiest to use. They consist of an individual tube of material with an inner size that’s equal in proportions to the shafts. The sleeve slips over the shafts so they meet in the middle of the coupling. A number of set screws could be tightened therefore they touch the very best of every shaft and keep them in place without passing completely the coupling.
Clamped or compression rigid couplings come in two parts and match together around the shafts to form a sleeve. They provide more versatility than sleeved versions, and can be utilized on shafts that are fixed in place. They generally are large enough so that screws can pass completely the coupling and in to the second half to ensure a secure hold.
Flanged rigid couplings are created for large loads or commercial equipment. They consist of short sleeves encircled by a perpendicular flange. One coupling is positioned on each shaft therefore the two flanges line up face to encounter. A series of screws or bolts can then be set up in the flanges to hold them jointly. Because of the size and durability, flanged products can be used to provide shafts into alignment before they are joined up with jointly. Rigid couplings are used when precise shaft alignment is required; shaft misalignment will have an effect on the coupling’s performance and also its life.
2. Flexible coupling flexible couplings are used to transmit torque from one shaft to some other when both shafts are slightly misaligned. Flexible couplings can accommodate varying degrees of misalignment up to 3° plus some parallel misalignment. Furthermore, they can also be used for vibration damping or sound reduction.This coupling is utilized to safeguard the driving and driven shaft members against harmful effects produce due to misalignment of the shafts, sudden shock loads, shaft expansion or vibrations etc.
3. Torque limiter coupling made to slip the torque out of the shaft to prevent damage to the engine or the application

What is the difference between rigid coupling and flexible coupling?
Couplings are split into types: Rigid and Flexible. In comparison withflexible couplings, rigid couplings have got limited application. Rigid couplings do not have the capability to compensate for shaft misalignments and so are as a result used where shafts are already positioned in precise lateral and angular alignment.
What are the benefits of flexible coupling?
Versatile couplings accomplish the objective of any kind of coupling, but their advantageover rigid couplings is they accommodate the unavoidable misalignment between shafts in some machinery. Versatile couplings also enable a degree of axial movement between the coupled shafts as may occur because of thermal expansion.
What are the types of coupling?
What is Coupling? Types of Shaft Couplings
Rigid Couplings.
Flexible or Compensating Couplings.
Clutches to certainly are a type of Coupling – We will the working on them separately.
Flanged Pin Bush Couplings.
Bibbly Coupling.
Gear Tooth Coupling.
Tyre couplings.
Elastomeric Couplings – This includes jaw type and S-flex couplings.
Couplings are products used to connect two shafts together and so are divided into two groups: Rigid and Flexible. Both are utilized for the objective of transmitting power, rigid couplings becoming more limited in applications in comparison with versatile couplings. Rigid couplings are used where shafts already are positioned in specific lateral and angular alignment. Their design will not enable any misalignment between shafts, but are generally able to transmit more power than versatile couplings. Versatile couplings are designed to accommodate misalignment between shafts and different types of load conditions. Many styles and types of couplings are available. For successful coupling selection, application circumstances should be clearly understood.