percussor
/pərˈsʌsər/Definitions
1. noun
An agent or instrument that brings about a change in or removal of something, especially by striking or knocking.
“The percussor in the rock drill was designed to break through the hardest granite.”
2. noun
A device or instrument, especially in a machine, that strikes or knocks, as to remove or break something.
“The percussor in the mechanical press was used to knock loose the metal parts.”