Advantages:
High torque capabilities
Different material choices for the spider allow the user to choose torsional stiffness
Somewhat “fail-safe”, in the sense that the driving hub will continue to turn the driven hub after failure of the spider
Easy installation in blind or difficult installations – all jaw couplings have through bores
Dampens variations or spikes in torque, usually caused by the driving element, protecting the support bearings and the driven component, and reducing vibration
Wear element can be reversed before being replaced, doubling life
Rugged, can function well in harsh environments
Replaceable, inexpensive wear element
Disavantages:
Relatively high reactive forces exerted on support bearings, proportional to misalignment
Even preloaded, so-called “zero backlash” jaw couplings have considerable wind-up, which is essentially the same as backlash, and disqualifies jaw couplings from servo applications
Accommodates relatively small misalignments, considering large size of couplings
Typical Applications:
Pumps, particularly gear, lobe, vane, and reciprocating pumps; also applications involving piston motors, or any system with high torque and vibration, where relative angular location of the two shafts need not remain constant. High-temp spider option good for down-hole directional drilling applications.