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

Jaw couplings are flexible connectors that use an elastomeric insert to transmit torque while accommodating minor shaft misalignment. To support these functions, they are typically built with a modular structure that enables fail-safe performance and dampens mechanical vibration. In this blog, we will explore how jaw couplings are constructed, where they are commonly applied, and how they should be handled during installation and maintenance.

What Are Key Design Features of Jaw Couplings?

Jaw couplings feature a modular structure composed of two metal hubs and a flexible elastomer insert. Several distinct design elements contribute to their ability to transmit torque effectively while compensating for limited angular, axial, or parallel misalignment.

• Hub Geometry: Each coupling consists of two hubs with curved jaws that are engineered to interlock with a central elastomer insert to establish a secure, continuous torque path.
• Elastomer Spider Element: Typically made of materials like NBR, urethane, or Hytrel, a flexible elastomer spider is positioned between the jaws to absorb shock, buffer vibration, and maintain torque transmission.
• Interference Fit Tolerances: In zero-backlash configurations, an elastomer fits snugly between the jaws to remove mechanical play and support repeatable motion transfer under load.
• Fail-Safe Structure: Certain jaw coupling models are designed with a fail-safe geometry, allowing the interlocking metal jaws to continue transmitting torque temporarily if the spider degrades or fails.

What Are Common Applications for Jaw Couplings?

Jaw couplings are widely used in industrial equipment where compact component design, misalignment tolerance, and minimal maintenance are critical performance factors. These combined traits make them a consistent choice in motion systems like:

• Pumps and Compressors: Jaw couplings are frequently used to connect electric motors to pumps or compressors, where they help accommodate angular or parallel shaft misalignment and suppress vibration in continuous-duty operating cycles.
• Conveyors and Material Handling: Conveyor drive systems often incorporate jaw couplings to smooth out torque transmission during start-stop operation and to absorb shock loads associated with shifting payload conditions.
• HVAC Systems: In heating, ventilation, and air conditioning (HVAC) equipment, jaw couplings are used in fan and blower assemblies to promote quieter operation in various residential and commercial environments.
• Food and Packaging Equipment: Jaw couplings are preferred in many food processing and packaging lines due to their lubricant-free operation, which supports sanitation compliance and reduces the risk of product contamination.
• CNC and Automation Equipment: CNC machinery and automated production systems commonly utilize specialized jaw couplings to transmit precise rotary motion between motor and shaft components while still allowing for small alignment deviations.

What Are Optimal Practices for Installing and Maintaining Jaw Couplings?

Jaw couplings are known for their simple construction, but achieving long-term reliability still depends on adhering to proper installation techniques and routine maintenance practices. To help reduce premature wear and avoid unplanned system downtime, technicians typically follow a defined set of best practices that include:

• Shaft Alignment Checks: While jaw couplings are engineered to tolerate limited angular and parallel misalignment, excessive deviation from proper alignment can accelerate elastomer wear, making periodic shaft alignment verification essential during servicing.
• Tightening Sequence and Hub Fit: Coupling hubs should be mounted using uniform torque across all set screws or clamping bolts to preserve concentricity and prevent shaft slippage or vibration under load.
• Diagnostic Indicators of Imbalance: Technicians should monitor jaw couplings for signs like excessive noise or abnormal vibration, which may indicate coupling misalignment or rotor imbalance.
• Replacement and Reassembly Protocols: When replacing a worn spider insert, both coupling hubs should be fully removed, cleaned, and inspected for damage or uneven wear before installing the new elastomer to ensure correct fit and functional alignment.

Browse Our Inventory of Jaw Couplings at Your Leisure

Owned and operated by ASAP Semiconductor, Stacked NSN is a purchasing hub where you can secure competitive options on reliable jaw couplings that are sourced from a network of renowned manufacturers and suppliers. Whether you require parts that are new, used, obsolete, or hard-to-find, you can rest assured that our team members will always strive to provide high-quality items, all while aiming to address any time constraints that you may have. Keeping our commitments in mind, see why a plethora of professionals steadily choose to shop on our platform when you kick off procurement with us today.

1. andrew brown
2. Posted on December 1, 2022
aviation

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