shear pin

noun

1. an easily replaceable pin inserted in a machine at a critical point and designed to shear and stop the machine if the load becomes too great

Example Sentences

But Mr. Tester, a third-generation lentil and pea farmer trying to make up for a late spring, was far more concerned with a broken shear pin that had stopped his bright red auger, which he needed to raise and store leftover seed from the 1,800 or so acres his family has been working for a century.

From New York Times

In some snow-clogged January to come � perhaps even the snow-clogged end of this dusty and confounding January � when the car won't start and the snowblower has broken a shear pin and the school bus has not ar rived to drag the kids off and leave the adults in peace, it may even look good.

From Time Magazine Archive