Carl Prinzler

Carl Prinzler was the Manager of the Builders Hardware Department at the Vonnegut Hardware Company in 1903. Prinzler, along with his architect and engineer neighbor Henry H. DuPont, developed the first "panic bar" device for doors which can be opened from the inside despite being locked on the outside. This idea and subsequently an invention came about as a result of the Iroquois Theater Fire. Prinzler devoted himself to the invention to ensure another tragedy such as this never happened again.

The panic bar was marketed under the Von Duprin name. Von Duprin is a company which makes security related products.