One of our great founders here at the Autopian has made it his life’s work to call out the inadequacies of most of the current self-driving systems in cars. However, there is a bigger issue that seems to be getting worse in automobiles as many designs change to rear windows that are painfully short in height.
What’s with these tiny wipers?
source: CarsDirect
I mean, look at the area these things actually clean…it’s a joke. Sure, some people will say that rear view cameras, giant screens, and beepers make a rear window of any kind superfluous today. To that I say shut up the fuck up, Elon. I think MOST people want to look out through the backlight, and through more than just some dinky little arc when it’s raining/salt spray covered.
One option is to add more little wipers like on the windshield of an old MG or a Toyota FJ Cruiser:
Sources: ebay and The MG Experience
Or for a rear window, the Toyota Cressida wagon went all-in with twin wipers:
source: Japanese Nostalgia Car
Still, these are kind of clunky solutions. I want a big wiper that covers most of the window. Imagine never having to squeegee the backlight at a gas stop ever again.
So I looked at the mechanisms that are used INSIDE rear windows, for window shades and cargo covers.
You’re familiar with the scissor-type things that lift the rear window shades on fancy ass cars.
source: ebay
So the wiper would work the same way. I’m thinking two wiper arms that would sweep inwards like a Renault Alpine, but the arms would attach to the wiper “beam” in tracks so the beam would stay parallel to the window. Pretty simple mechanism, and it pushes down so heavy snow would have gravity on its side, and the ‘beam’ would park in the upper lip/duck bill most cars have above the window.
The unit could utilize standard wiper blades in standard sizes…just whatever two or three across standard sizes would fill the space (maybe overlap to eliminate any lines). It MIGHT need internal springs or something to center the wiper – remember the sunshade will self-center because it is a roll.
But see below how it cleans all visible opening on the window:
Another idea for this would be a cable system like that one used on power cargo covers. These things work with an overlapping parallel cable thing that lowers and raises the cover with a motor mounted below that tailgate threshold.
source: 5series.net
Pretty clean and slick BUT I know how it works ONLY because an identical vehicle is in my garage now and it has broken…twice. Now, if Toyota did this instead of Munich, it might be better. Still, for outdoor use, with tracks that could fill with ice… I think the arm system might be better.
So, could either kind of mechanism create a full width rear window wiper? I’m a nerd but not an enginerd so I need your help! Tell me in the comments here if this is viable and deeply important or just madness!
What limits rear visibility isn’t the wiper arc, it’s the rear-seat headrests. Those need to retract or fold down to seatback height for the 90% of the time you’re running solo.
Many econoboxes with only nominal back seats have this. My buddy’s Yaris has headrests that push down really far. Our Elantra GT which has a real back seat has normal headrests, but I don’t really notice them blocking my view anyway. The middle headrest is short though.
Yes! Folding headrests are not nearly as prevalent as they should be in the age of mail slot rear windows. They’re standard on recent Prius models and Volvos and it’s yet another reason I’m loathe to give up my Prius in this day and age.
Reclining second rows are an acceptable substitute, however, and give me hope, but they’re still all too rare and limited in their functionality. The Prius doesn’t make me sacrifice cargo space for rear visibility.
I think David needs to write a follow-up. The design concept is there, but there are variable to account for. Any any good former engineer would be compelled to do the math.
The idea of the “roll” up shade is interesting but it’s the opposing motion with opposing forces. There forces exerted in the shade are always the same, there known and fixed. With a wiper it could be rain snow or ice. There is almost an infinite number of variables depending on what the weather is dictating on the rear screen.
This idea seems theoretically could work, but there is a calculated rate of failure that you would have to be willing to deal with. The cost of a current arc style broken wiper blade is reasonable. It would seem failure on the push down would not be the blade but the mechanism. And most of us have probably been unfortunate to find out the cost of replacing a window mechanism.
Eager for DTs input. Or even a car designer on how it just mess with the fung shui of his design is completely thrown off by logic.
Finally, my useless knowledge of cameras is, uh, useful!
Both styles of wiper are essentially a very large, very slow, very simplified focal plane camera shutter — the wiper bar with arms is similar to the high speed shutters in virtually every current camera, and the roll mechanism more like a Speed Graphic.
Drum-style cloth shutters like the roll-up wiper are very easily knocked out of their tracks on hitting an obstruction. I can only imagine this tendency would increase as you sized up the mechanism, since the lever action exerted by an obstacle which skews the shutter blade and derails it would compound massively.
Metal or plastic blade shutters opened and closed by a pivoting arm tend not to fail by getting knocked out of their light trap guide channels — the arm keeps on powering through the obstructions and its attached blades just straight up break. So my sense is that it would be easier and more reliable to strengthen that pivoting arm mechanism and have replaceable wide blade wipers rather than make a beefy turbo drum and cable mechanism, which would also be much heavier and more internally complicated to maintain.
I also would like to see David tackle this.
You forgot the Mercedes single wiper that was on the windshield, that could be made smaller. I have a TSX wagon and it’s not big but I can see.
Mercedes Uniblade is another option
https://www.youtube.com/watch?v=HKGhKrQmK68
I think you need a drive arm interacting with an arm that both slides along a short track and pivots from the slide…
…or the industry could look at using self cleaning glass and an effective water based washer system.
Upscale the headlamp wipers from a saab 99. Job done.
I guess you’d leave them in ‘deployed’ mode at the top of the glass when off, that way the shaft could recess in the tailgate
’90s Toyota Camry wagon also had twin rear wipers. Another idea is to put the pivot at the side of the window with a parallel arm linkage to a horizontal wiper. blade Motor coaches use these linkagas to cover those huge windshields. I propose to just turn this rig on its side.
Okay 1st best bishop column so far. I loved it. I’m think in the rear of a vehicle wipers could be mounted on the top of the window solving snow and frozen issues. Also the wiring would be easier on a hatch. Now if you have a barn door rear door let’s get freaky with side mounted wipers. Up and down with an arc or just side to side like a squeegee. I think they just copied the wiper system from the front to reuse parts and no design money needed.
Dave- I believe that the Mini with the barn doors does that and it clears a pretty good chunk of all of the glass
I’ve seen that on some minivans too, either the Odyssey or the Sienna, can’t remember which.
A pantograph wiper system would work for this, you select blade length by the height of the glass.
https://www.scanwipers.com/marine/electrical-pantograph-wipers/
cal67- it’s a good system but as we commented earlier, you need more height. Unless I’m missing something, if you were to use this system on the window in the picture I posted, the pivot point for this wiper would need to be like two feet above the top of the roof.
Actually you can select different wiper sizes on your windshield from OEM sizes as long as they fit. An inch longer wiper, depending on the brand is only a half inch longer in each direction.
A mechanism like the Mercedes 124 front monowiper would be cool. What could go wrong?
hammertime- that’s already been commented on; cool system but not enough reach to cover the short, wide rear window.
Need an on-board air compressor and a thin long nozzle along the edge of the window! 😉
Speedypancake- I think that is the Elon Musk solution he wants for Cybertruck…but it must not be working since the latest ‘production’ versions show a comically big standard wiper.
Yeah I’m not confident they even have that figured out yet, there’s no way it’s coming out anytime soon.
I like the idea… But I forsee a lot of broken wiper mechanisms in the icy parts of the world.
Personally I like the multiple wiper solution, I always thought it denoted purposefulness, going back to the first time I saw them on an XKE. You solution is also good, I worry about rigidity. but something bigger that is articulated like if it pivoted in the corner of the window, and half or 2/3 of the arm could flex. As the arm rotated, part of it can keep moving even as the tip has hit the top of the window, completing the sweep, squaring the arc. dammit, super easy to draw, impossible to describe.
Black Peter- I think I understand what you are saying. Actually, if you look at some of the wiper solutions for rectangular euro lights you can see something similar, as well as other interesting ways of cleaning these odd shapes.
dogisbabob- kinda points in that direction, don’t it?
Another solution: make the fucking windows bigger!
You’re still trying to clean a square area with a arc. Look at the Cressida wagon, that’s a fine 80’s sized rear window, and it needs two.