Torque limiter

A torque limiter is an automatic device that protects mechanical equipment, or its work, from damage by mechanical overload. A torque limiter may limit the torque by slipping (as in a friction plate slip-clutch), or uncouple the load entirely (as in a shear pin). The action of a torque limiter is especially useful to limit any damage due to crash stops and jams.

Torque limiters may be packaged as a shaft coupling or as a hub for sprocket or sheave. A torque limiting device is also known as an overload clutch.

Disconnect types

Disconnect types will uncouple the drive, with little or no residual torque making its way to the load. They may reset automatically or manually.

Shear pin

A shear pin type sacrifices a mechanical component, the pin, to disconnect the shafts.

Synchronous magnetic

A synchronous magnetic torque limiter uses permanent magnets mounted to each shaft, with an air gap between. They are very fast acting, but may have more backlash than mechanical types. Because there is no mechanical contact between the two shafts, they are also used to transmit torque through a physical barrier like a thin plastic wall. On some models, the torque limit may be adjusted by changing the gap between the magnets.