Torque overload protection is often overlooked in machine design until something jams resulting in expensive damage and down time. The R+W Series SK2 safety coupling was developed specifically for this purpose. It uses a patented ball detent system that is absolutely backlash free and will disengage within 1 to 3 milliseconds when an overload is detected.
Four versions are available including a single position, multi-position, load holding, and free wheeling. These couplings are preset in the factory to a customer specified disengagement torque and can be adjusted in the field after installation.
These unique couplings are manufactured with a stainless steel bellows exhibiting very high torsional rigidity with zero backlash. The moment of inertia is also very low due to its low mass and low weight, making them ideal for servo driven systems.
The SK2 couplings are available for a torque range of 0.2 to 1800 Nm (1.8 to 15,930 in. lbs.). Both shaft hubs are custom bored for shaft sizes of 4 to 80 mm (0.25in to 3.125in.).
More details at http://www.rw-america.com/torque-limiters/index.html