On November 10, 1964, U.S. Patent No. 3,156,177 on Food Preheating, Cooking and Warming Device issued to Harlan Sanders:

A few years later, the Colonel received a second patent, U.S. Patent No. 3,245,800 on a Process of Producing Fried Chicken Under Pressure:

Interestingly, in the Process of Producing Fried Chicken Under Pressure it is the chicken that is under pressure, not the poor cook behind the counter.