Some cone CVT models use two rollers.[23][24] In 1903, William Evans and Paul Knauf applied for a patent over a consistently variable transmission making use of two parallel conical rollers pointing in opposite Instructions and related by belts that may be slid alongside the cones to vary the transmission ratio. https://gearboxcvt32085.blogproducer.com/39567699/gearbox-cvt-for-dummies