"wiper tag"

[larrybadger]

"Wiper Tag"
Lead article brings back memories of when I was pushing snow for a living here in western Michigan. We get a goodly share of the white stuff, both from normal systems coming through and lake-effect off Lake Michigan. I am reminded of a morning when I was traveling on U.S.131, a north-south highway notorious for icing over. Here I am driving it from one job to another when I decide to play "wiper tag" between the elements, my wipers, and me. Well, as the article states is how I started this round, arm out window grabbing wiper blade assembly as it nears hand...etc. Well, was going well, until on one grab the entire blade assembly came off in my hand. So here I am driving in a nasty snowy/ice condition, with the wiper arm creating a nice scratch into my windshield, while at the same time playing a not-so-gentle scratchy melody. I have to leave them on so I can have some visibility of the side of the road, and am reaching out trying to use my ice scraper to clear enough of a patch so I can see enough to pull over; which in itself is not a pleasant thought to have to do on a major highway, in a snow/ice storm. Needless to say, I now take the time whenever safely possible to pull off and clean everything instead of playing the game of "wiper tag". And while we're on the topic of wipers, can anyone explain to me why it is that when wipers start wearing down they always seem to do so right in the direct path of vision, instead of at the ends or somewhere else? So you have this perfectly clean windshield, with a 2-3 inch wide arcing path of blur right in front of your eyes.

Larry Badger
Plainwell, Michigan

 

[DocRushing]

RE:

Larry:
I love to answer questions.
I'm a former professor, and I have a strong background in physics and engineering, so I love to answer questions.
A wiper arm is spring-loaded -- so that it holds the blade against the glass.
The arm is attached to the blade holder at or near the center of the holder.
The spring (through the arm) exerts its maximum force in the region of the center of the blade, thus holding the blade against the glass most firmly near the center of the blade.
But the blade and its holder are slightly flexible, so the blade "hugs" the glass along its length, but it does so most firmly near the center and less firmly near its ends.
Thus the blade wears most rapidly near its center and less rapidly near its ends -- because the spring holds the blade most tightly near the center of the blade and less tightly at its ends.
Therefore, when the blade begins to wear out, you get a smeared stripe in your line of vision even though you get clearer stripes at the ends of the blade.
(To visualize this, recall the times when you have sanded a piece of wood. The harder you pressed on the sandpaper, the more rapidly you ground down both the wood and the sandpaper. The more lightly you pressed on the sandpaper, the less rapidly you ground down both the wood and the sandpaper.)
If I gave you more of an answer than you wanted, please forgive me.
Merry Christmas!
Doc.

 

[plumcrazy8]

RE: wiper design

Hey DocRushing, I need someone to answer this one. I've wondered for years why the blade companies continue to use the EPDM formulation for blades when there are so many more durable compounds out there. I come from a chemistry background in the field of industrial polymers and it amazes me why we haven't seen more urethane and silicone formulations. a FEW on the market now sport these "new" technologies but EPDM is tire tubber (as far as I know), subject to uv and stress degradation. Any ideas? Please don't tell me it's just cost.

 

[RichM]

RE: wiper design

Many years ago my Ex Wife's Uncle received a patent on windshield wipers made out of teflon.He sold the patent to Ansco who makes wipers,they were supposed to manufacture them and he would receive royalties. Unfortunately for him they sat on it and to the best of my knowledge never manufactured them. He also had them with different colors to match a vehicles paint.

 

[DocRushing]

RE: wiper design

Plum:
I too share your curiosity about that.
My father drove 37 years for Greyhound Lines.
(That's how this driving stuff got into my blood.)
He and his fellow drivers had their favorite gripes about problems with the equipment.
Several of their big and constant gripes dealt with the wipers.
While I was a kid, I heard their gripes in the 1940s and -50s.
Now I still hear and see (and feel myself) some of the same old gripes -- justifiably.
Yes, a number of improvments have taken place -- especially with heavy-duty electric motors (instead of Trico air motors), multiple speeds, and intermittent-wipe features with controllable delay.
Yet, as you said, little or no progress has taken place on the chemical side of the blades.
Why?
I wish I knew.
Maybe an insider can tell us more about that.
I do now use a nifty product in cold weather -- blades called arctic or winter blades -- a blade with a soft, flexible, light-gauge rubber boot which encloses the blade-holder assembly.
While the wipers operate, as the wipers sweep to and fro (expecially when they reverse directions), the motions of the blade holders flex the boots -- in such a way as to agitate the freezing water -- enough to slow down the accumulation of ice on the blade and the holder.
Most of the time under most conditions those blades really do work -- they remarkably slow down the accumulation of ice -- and therefore the need to play wiper tag.
Those blades are available, I think, from both Anco and Trico -- and they're available even at WalMart in the northern states.
At Wally the price is only slightly higher than for a standard blade.
Happy New Year to all!
Doc.

 

[plumcrazy8]

RE: wiper design

Hey Doc. Yup have used the winter blades for quite a few years myself and the mechanical aspects of the design are great. Now to get to the bottom of that nagging rubber formulation..........

 

[silverdollar]

RE: wiper design

Did you ever think that companys need blades to wear out so that they can sell more.

 

[DocRushing]

RE: wiper design

If there were a monopoly in that market (with only one seller), or if there were an oligopoly (with only a few sellers), that consideration (forcing frequent replacement) might well be a part of the strategy of the seller(s).
But entry into the selling side of that market is relatively easy, and there is much competition among the sellers, so even the top few large sellers do not have the power to dictate and enforce a replacement policy on their own terms.
So we still wonder why nobody has yet placed a better line of blades (made of better material) on the market.
Maybe someday a true entrepreneur will introduce a better blade (even if not a better mousetrap).
Happy New Year!
Doc.

 

[theoldprof]

RE: wiper design

On the subject of wiper blades, I very frequently notice SUVs and the like have their rear wiper blades wrapped in clear plastic wrap of some sort. Any body have any info on that practice? :+ :+

 

[copdsux]

RE: wiper design

I believe that means that they have recently been through a car wash and a protective cover is placed over the rear wiper to keep it from being ripped off the vehichle by the "washing machine".

 

[twodogsdaddy]

RE: wiper design

As a current car wash manager I can definately say that you are quite correct about those little bags on the back rear wipers. In the summer we'll just put a little strip of tape over the wiper assembly but in the winter the tape usually won't stick hence the plastic bag. One of the driers is supposed to take them off because we use them over and over. At the new car wash we don't use them..we're using a lighter pressure on the wraps ...sorry probably more info. than is warranted....Hopefully sometime in March or early April I'll have it all behind me and will be back out on the road...hopefully in expediting...It's been a little over three years since I've driven...checking into a couple of schools for a refresher just to be on the safe side. I did like the article on the company out of Michigan (?) that is selling the heated winshield wipers. Looks promising