First attested in the 1590s.

What does clevis pin have at its head?

Clevis pin

Threaded clevis pins have a partially threaded shank on one end and a formed head on the other. The formed head has a lip, which acts as a stop when threading the pin into the shackle, and a flattened tab with a cross-hole.

What is clevis used for?

Shackles and clevises are U-shaped mechanical couplers closed by a pin or bolt. They are used to facilitate attaching a chain, wire rope or synthetic sling for rigging, towing and lifting.