A chin guard is mainly there to keep your helmet on.
Protect
Protect
they guard each other
"Guard" in Spanish can be translated as "guardia" or "guarda".
The cast of A Chin He Loved to Touch - 1927 includes: Al Cooke Lorraine Eason Kit Guard
The cast of The Chin He Loved to Lift - 1927 includes: Al Cooke Lorraine Eason Kit Guard
A guard
guard
to protect the coastal towns
to watch over the people or to protect the people from harm
the helmet Alternative answer: the structure that cupped the chin specifically is called the Bevor. Several helmet types, such as the great bascinet and armet would protect the chin without a bevor, however.
Better known as a bollard, a post guard (or guard post) is a short vertical post meant to prevent access and protect assets.