[1] Mercier fled France for the United States during the Nazi invasion, eventually settling in New York City.
In 1943, Jean Mercier recognized an opportunity for his bladder type accumulators in Hamilton Standard's hydromatic propellers.
There was a single insurmountable problem—weight, which was a problem since World War II aircraft were quite small.
Greer and Mercier formed a patent company (Greer-Olaer) and Greer Hydraulics became the sole licensee, with the rights to continue development and to license other companies outside the U.S. From the early 1950s, bladder-type accumulators became the unit that was specified and used in almost every application where hydraulics was employed - machine tools, plastic machinery, circuit breakers, rock crushers, oil drilling, farm and road machinery, to name a few.
[2] He was also decorated Chevalier de la Legion d'honneur by the French Republic.