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This latest installment of MC² shines the spotlight on couplings.

A coupling is used to connect together two rotating shafts in order to transmit motion, or in more general terms, to transmit power. 

Couplings are characterized in different ways, but one common way divides them into rigid and flexible. Rigid couplings are preferred in cases that call for precise shaft alignment while flexible couplings are used mainly for transmission of torque and where some misalignment is acceptable. The type of application will usually dictate the right kind of coupling to use.

Here you’ll find resources on the basics of couplings and how to select the right one that will satisfy the particular application requirements. From technical overviews to selection tips, information is included on the many different kinds of couplings including bellows couplings, gear couplings, beam couplings, and servo couplings, among others.

Miles Budimir

Senior Editor, Design World


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Power Transmission • Servo • Systems

Couplings for PT and motion designs: Technical Summary

Couplings are devices that connect two shafts for transmission of torque from one to another.

What are couplings for power-transmission drive shafts?

All couplings serve to transmit drive torque and angular velocity.

9 considerations when picking servo couplings for servo applications

Couplings for servo applications usually connect precision drives to sensitive loads, so they cannot induce any error. 

Six factors to remember about couplings in a motion system

Physical values such as torque, torsional rigidity, spring stiffness, and moment of inertia, play a major role in coupling design.

One form of flexible coupling with very low and near zero-backlash is the bellows coupling.

What are Bellows Couplings? Technical Summary

Flexible-coupling considerations for motion-control designs in OEM and plant setups

Couplings connect rotating shafts in equipment powered by electric motors and other drives. All transmit torque and angular velocity. Flexible variations compensate for misalignment. Many of the latter even address vibration and improve system dynamics.


Technical Focus • Tips • Sizing

How to Size and Select Bellows Couplings for Motion Applications

Electrodeposited bellows couplings are commonly used in motion control applications.

Reaction forces from couplings: How to prevent or mitigate?

All flexible couplings compensating for misalignment cause reaction forces, and their effect is significant if misalignment is excessive.

What do you know about Gear Couplings?

Though one may not think of gears as being flexible, gear couplings are very much considered to be a flexible coupling.

Couplings see technological and economic growth

Two industry trends could spur change in the application of couplings over the next few years.

Ruland Manufacturing Co., Inc. is a privately owned company founded in 1937. They have carefully and responsibly manufactured high performing shaft collars, rigid couplings, and motion control couplings for the past 40 years and begun distributing machine components from carefully selected suppliers.

For coupling tips all the time go to couplingtips.com