The findings help explain why saber-teeth evolved so many times (at least ... Their increasing specialization may have acted as an "evolutionary ratchet," making them highly effective hunters ...

The spring is likewise kept to its required position by means of a pawl which catches into ratchet teeth on one of the flanges of the drum, and there is a similar contrivance on the other flange ...

moment for [Leo]. For a ratchet, he used a strip of bandsaw blade oriented so the teeth point upward. A complex bit of spring steel, bent to engage with the blade’s teeth, forms a pawl to keep ...