hard stop vs point in time

hard stop

noun
  • A definite time when someone must end a task in order to meet another time commitment. 

  • A mechanical device that limits the travel of a mechanism. 

  • A tactic used by armed police to stop a vehicle believed to contain dangerous criminals. 

  • Synonym of full stop 

point in time

noun
  • A moment (of time). 

How often have the words hard stop and point in time occurred in a corpus of books? (source: Google Ngram Viewer )