It’s to a small degree exhausting to check, that is why we've got that video, however the most purpose is that, by proscribing sure degrees of freedom, and leaving others, you'll translate unidirectional rotation into translation of wiper arms.
As for the various styles: well, you’ve got your typical pivot-style mechanism shown on top of, that is reasonable and straightforward, the' to a small degree massive and significant, and you have got to use a special system supported whether or not the automotive is sold-out in right or hand drive markets (you need to flip the direction).
Then there’s the opposed vogue window wiper blade system, whose wiper arms pivot concerning shafts placed within the lower corners of the screen. These systems are nice, as a result of they clean plenty of the window (including the corners) and therefore the solely half left un-wiped is behind the rear view mirror—a a part of the windshield that you just don’t really want to appear through anyhow.
Plus, they'll be utilized in hand or hand drive markets. But, they’re rather ungainly, complicated (seriously, explore this video of it moving in-vehicle) and pricey compared to pivot wipers.
My favorite vogue comes from Mercedes, whose mono-arm window wiper blade transmission is nice as a result of it’s atiny low package, cleans quite an little bit of the glass (since the window wiper blade really extends towards the corners because it moves), and it are often utilized in variety of various markets. However it’s dear and sophisticated compared to different systems.
So really, like all engineering choices, it’s a trade-off between packaging house, complexness and value. however notwithstanding what automakers select, these wiper transmissions that move wiper arms back and forth to wash our windshields are plenty a lot of fascinating than I ever would have guessed.