Some cone CVT styles use two rollers.[23][24] In 1903, William Evans and Paul Knauf used to get a patent on a consistently variable transmission working with two parallel conical rollers pointing in opposite Instructions and related by belts that would be slid alongside the cones to vary the transmission ratio. https://archerghecy.bloggazzo.com/31871493/the-greatest-guide-to-gearbox-cvt