AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

What Is a Jaw Coupling and What Are the Parts That Make It Up

Across a variety of industry verticals, one will typically find jaw couplings being used for power transmission in large, industrial machines. That being said, they often find homes in smaller, standard power transmission applications, and they offer the unique advantage of not requiring lubrication for mitigating movement. Made up of three components, two jaws and an elastomeric spider, jaw couplings operate in a single plane between two hubs to transmit power from a driving hub to a driven hub. For your better knowledge, this blog will take a closer look at jaw couplings, how they are used, and the advantages of different designs.

Jaw couplings are all-purpose power transmission devices that work in a wide range of applications and environments. Despite their simple composition of three elements, jaw couplings work well in a range of temperatures, angular misalignment, and chemicals, as well as have good speed and dampening capabilities. The insert is the middle component that sits between the two hubs, and it handles the transmission of power by harnessing mechanical energy between the two hubs, those of which are typically bored to a clearance fit tolerance. The insert, or spider, is an elastomeric coupling that transmits torque between the driving and driven hubs. As such, when the insert fails, the hubs will interlock and continue to carry the load without the damping capability provided by the insert.

The elastomeric insert of a jaw coupling is unique from others in that it is in compression. In other words, elastomeric couplings are classified as being either for compression or shear, and these terms refer to the means by which the elastomeric element transmits torque. For example, shear-type couplings rely on an elastomeric element that is suspended between two hubs in separate planes and must stretch. Meanwhile, the elastomeric elements, or spiders, of jaw couplings are compressed in the same plane between the two hubs and use their legs in this position to transmit and cushion the force between the two. Working on the compression principle, jaw couplings require no lubricant for smooth operations.

Since jaw couplings work well in the presence of dirt and particles, they are used in a number of applications. As such, both the jaws and the elastomeric spider may be procured in varying materials and sizes, as well as for different ideal operating environments based on one’s needs. Jaws can be manufactured from steel, aluminum, and stainless steel, as well as bronze, ductile iron, and powdered metal. Meanwhile, spiders may be made of polyurethane, natural rubber, urethane, hytrel, and in special cases, soft metals such as bronze for low speed, high torque applications. Furthermore, typical bore diameters range from 1/8 to 7 inches, and torques range from 3-1/2 to 170,000 in.-lbs.

Given their versatility, it is no surprise that jaw couplings are popular for power transmission. With only three parts, they are simple to install and easy to use. Operating when the spider fails and requiring no lubrication maintenance, jaw couplings are fail-safe solutions to your power transmission needs. Whether working with large industrial machinery like pumps and blowers or working with smaller motion control systems, procuring a reliable jaw coupling is important to your machine’s performance. As such, be sure to procure all of the part types you require from trusted distributors like Stacked NSN. Owned and operated by ASAP Semiconductor, we offer unparalleled access to an ever-expanding inventory of premium part types from suppliers we trust around the world. With rapid lead times, around-the-clock service, and competitive pricing, make us your procurement partner today by submitting a Request for Quote (RFQ) form. To learn more, call or email us at any time!


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