A jaw coupling is a type of general purpose power transmission coupling that also can be utilized in motion control (servo) applications. It is designed to transmit torque 
(by connecting two shafts) while damping system vibrations and accommodating misalignment, which protects other elements from damage.
Jaw Couplings are one of the first and even now hottest elastomer couplings in the globe due to their inherent simplicity. Two identical hubs with 3 face lugs are linked through a superstar shaped element, sometimes known as an insert or spider. The 3 piece design makes them easy to work with and well-known on applications such as pumps, enthusiasts, blowers and compressors.
Jaw Couplings need no lubrication and offer high reliability for light to moderate duty applications with good alignment of equipment and no requirement of torsional dampening.
In regular operating conditions there is absolutely no metal to metallic contact so the life of the hubs is virtually indefinite. However, in a catastrophic failing of the component the load would be carried by the hubs offering a amount of failure protection. Jaw couplings are resistant to oil, dirt, moisture and grease.
Specific element materials are available to achieve maximum performance for the operating conditions.
The standard element material is NBR (N)-‘Synthetic Rubber’. It is highly flexible, oil resistant and the torsionally softest of the component options. It has a heat operating range ideal for most commercial applications and allows for up to 1 1 degree misalignment capability of the connected shafts. NBR is the most economically priced option.