The torque limiter consists of two co-axially mounted members locked together by a cluster of spring loaded balls acting as slideable links between the two halves of the unit. Overload forces the balls out of their seats which continue a ratchetting motion until relative rotation between the two halves disappears.
One of the ball pockets contains a spring loaded pin slightly protruding from the face of the torque limiter. When slip occurs, the pin acquires a reciprocating motion of 2-3 mm stroke and may be used to operate a switch or any warning device. In addition, slip is accompanied by a whirring noise which acts as an audible warning.
The outside diameter of the drive ring is ground to size and its face contains threaded drive holes and a location spigot. Thus, either a sprocket or a pulley may be bolted to the drive ring, ensuring that the resulting side load is carried well inside the bearing.
