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Top Tech Tip: 5 reasons to consider using jaw couplings

Ruland zero-backlash jaw couplings are available in bore sizes from 1/8 in. to 1-3/4 in. or 3 mm to 45 mm, and with spiders in three hardness levels. [Credit: All images courtesy of Ruland]

 

 

Jaw couplings are components commonly used in servo-driven systems, where precise motion control is required. Chris Gumas, Director of Customer Experience with Ruland Manufacturing, gives five reasons when you should consider using jaw couplings in your design.

1. Balanced, zero-backlash design
Jaw couplings are a three-piece assembly comprised of two jaw coupling hubs that press fit onto a jaw coupling spider. The press fit concentrates forces to the center of the spider's limbs and allows the coupling to operate with zero backlash. Jaw couplings are commonly used in servo-driven systems with high acceleration and deceleration curves where precise motion control is required and a low-inertia, balanced design is desired.

2. Elastomer spiders
Spiders are available in three durometers, allowing the user to find the right balance of stiffness and compliance in their application. The advanced polyurethane material allows the spider to absorb shock loads without damage to the motor or other sensitive system components. They serve as the wear element in jaw couplings and make for an inexpensive, simple replacement compared to other styles of coupling that require complete replacement at the end of their usable life.

Three-piece assembly: Ruland curved jaw coupling with flexible spider insert.

 

 

3. High customizability
Hubs with the same outer diameter can be mixed and matched and are manufactured in clamp or set-screw styles, and they can have inch, metric, keyed, or keyless bores. A selection of three elastomer spiders triples the potential combinations, giving designers a variety of ways to optimize their system. An additional benefit of the three-piece design allows for blind assembly in systems with limited shaft access.

4. Hub separation
Ruland jaw couplings are designed to accommodate all forms of misalignment with proper spacing between both hubs. Stand-offs on the spider limbs maintain proper spacing between the two hubs during installation, ensuring full misalignment capabilities. As the connecting element, the elastomer spider also interrupts electrical currents, making jaw couplings electrically isolating.

Ruland curved jaw coupling on shaft.

 

 

5. Fail-safe design
If the spider fails or is otherwise compromised, the jaws of the hubs interlock for direct power transmission, allowing the machine to be shut down safely. When this type of failure occurs, the spider can be replaced, allowing full coupling performance to be restored. Systems that would otherwise suffer damage from sudden coupling failure benefit greatly from this continued functionality, and the sound of the hubs interlocking will alert any nearby maintenance personnel.

Learn more about Ruland jaw couplings at ruland.com/servo-couplings/jaw-couplings.html. Contact Ruland at 508 485-1000 or contact customer support at ruland.com/contact-us/customer-support.

About Ruland
Ruland Manufacturing Co., Inc. has carefully and responsibly manufactured high-performing shaft collars, rigid couplings, and motion control couplings for the past 40 years. Ruland's product line was recently expanded to include a variety of machine components from select manufacturers that align with Ruland's performance and quality standards. Ruland is a privately owned family company founded in 1937.

Source: Ruland

Published January 2026

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