Invented by Willis JOhnson, the egg beater was patented in 1884. Originally he inented the device as a mixing machine not intended to whisk the eggs only. The rotary beater transfers the action of whisking into gears, which saves a lot of effort. It converts slow rotation into a much faster rotation that works through two bevels in opposite directions. It works by hand cranking the large double-sided drive wheel which transmits the motion of the handle to the two bevel pinions that spin the beaters. The rotary egg whisk comes in handy to save a lot of effort and time. It's been manufactured in a variety of styles by a large number of manufacturers and was designed into many different forms. It also brought out the later electric mixer invention.