Algodoo

After replacing the belts on my lawn mower i wondered how the transmission worked and this is what i discovered.

Simply put by increasing the belt tension, by pulling on the pulley in the middle, the belts are displaced inside the pulley outward or inward changing the diameter and ratio. The middle pulley has a free floating middle which makes it work.

Not 100% to scale or design of my lawn mower.

Exploded view of my lawn mower pulley system:

https://polr.partstree.com/v1/iplimage.php?ir=YTozOntzOjY6ImxpbmVJZCI7czozOiJtdGQiO3M6OToiaW1hZ2VQYXRoIjtzOjE2OiJNREE1TVRFd01Gd3dNREE0IjtzOjc6Im9wdGlvbnMiO2E6MTp7czo1OiJ3aWR0aCI7aToxMDAwO319