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Soft bumper
Soft bumper (working like baloons on sides of a ship) to minimize parking and even crash damage | |
I saw a movie in youtube, how a man parked his car in a gap so small that there was almost no space left between it and other cars. I felt sorry looking, how he bumped several tens of times into other cars bumpers, so I came an idea-what if car makers add or owners buy soft aftermarket rubber or plastic
(either hollow like balloons or not) "cushions" on bumpers of their cars to minimize damage by bumps-while-parking or by slow speed accident? It's pretty obvious, that this invention would minimize damage to paint or even bumpers themselves. Some things like these are already used on small ships, yachts-they look like balloons and are lowered before docking the ship, avoiding scratches and damage to sides of ship. If we build some kind of push feeling switch inside these proposed "cushions", we even could create a "zero distance park-tronic" device, that would show that we had touched another car without making a dent or scratch. Of course, if these "cushions" were dirty with mud, paint of another car would still be scratched, although not as much as from plastic bumper. And if a slow speed accident happens, these "cushions" would absorb a lot of energy in a nondestructive way, thus saving bumper from damage and owner from spending money on a new bumper.
IIHS bumper tests
http://www.iihs.org...persbycategory.aspx
3-6mph tests. Yikes. [DIYMatt, Dec 09 2011]
What a bumper should look like
http://www.team-bhp...-india-dsc08010.jpg
The black strip on the front is the hard rubber. [DIYMatt, Dec 09 2011]
[link]
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Back when Mercedes were good (1985) they had steel bumpers with a 3" thick rubber strip on the outside - presumably for ramming lesser cars out of the way. |
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I strongly suspect that car manufacturers have
realized that they can make another 10-20% on the
cost of the car by selling replacement "bumpers"
from time to time. In fact, the term "bumper" is no
longer applicable, since the plastic panels are big,
brittle, non-repairable, and usually house a variety
of expensive components such as lights and parking
sensors. Perhaps the term "sacrificial body-panel" is
more appropriate. |
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Actually the motivations are much more simple: minimize cost and weight, and maximize crash energy absorbtion. |
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//maximize crash energy absorbtion.//
Bumpers haven't done that in 20 years. I remember seeing some videos of a test done several years ago. It found that most cars have such awful bumpers that they will suffer thousands of dollars of damage from crashes under 5mph. Let me look for that link. |
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[DIY] Bumpers have gone from devices to prevent damage during low energy impacts to devices intended to absorb some of the energy from high energy impacts. |
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This is far more likely to keep the passenger alive in a high speed incident, but will be much more expensive at lower speeds. |
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You're confusing bumpers with crumple zones. At high enough speeds for crumple zones to come into play, bumpers will make a negligible difference. They are basically hollow plastic. |
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No I'm not. Many bumpers contain molded in place foam, with quite a bit of energy absorption capacity. Unfortunately, it doesn't prevent the outer layer of plastic from cracking. |
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I do a tidy side business fabbing real steel bumpers to go
on modern pickups that, despite all pretenses of
machismo, are factory-equipped with flimsy plastic shells
that crack and fall off the truck when struck by a handful
of wet cookie dough. Crumple zones are one thing, but
what they're passing off as bumpers these days are
pathetic. |
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One notice regarding bumper quality-when you crash yours, you can buy a cheaper taiwanese one, that is often even more rigid than original |
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back when I was working in the car repair industry
(5-6 years ago now) it opened my eyes as to how
much technology is in the typical "bumper".
They're often plastic or GRP because the sorts of
compound curves with multiple cut outs for lights
and grilles are simply impossible or expensive with
metal. The compound curves are necessary
because a: they look cool and b: they aid massively
in aerodynamics. Crucially, keeping the weight of
the bumper down means that a smaller proportion
of the weight is outside the wheelbase, which
means the car will handle better. |
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Also, there's considerable thought that's gone into
how they perform in a crash. If you're going to
have a crash, you WANT all the non-person
components to absorb all the energy and destroy
themselves. Simply take a look at a 180mph F1 car
crash. The only thing left is the driver and the
small safety cell around him. Behind the bumpers
are often one-shot friction dampers (at least on
BMWs....) to take the next load of energy out of
the crash. Given that (at least in the UK) road
deaths have halved twice between '85 and '05, I'd
say they're doing a good job. |
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If you're looking for a bumper protector for parking situations, Google "Bumper Bully" it's baked. |
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Compound curves in metal are hardly impossible, as any
talented panel-beater will tell you. Expensive, yes. These
days, it's the sort of thing you buy for looks. I've installed
masterfully-beaten panels (made in collusion with another
craftsman; not my art) on a couple of the rugged tough-
truck bumpers I've created. |
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I've never made a steel bumper for anything but a 4x4, nor
would I; beyond sheer tastelessness, it would be dangerous
and irresposible, not to mention frustrating. I have enough
trouble fitting and balancing the sensors found inside truck
bumpers, which tend to be pretty minimalist. I wouldn't
even begin to know how to adapt them to a 'soft' bumper. |
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I think the bumpers scratch easily specifically in order to make people scared to hit something. Otherwise you'd have drivers purposely nudging other cars and ramming into them out of anger. |
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Incidentally, police cars in NYC do have rubber bumper extensions, presumably to protect their bumpers, since police often purposely ram into things (I guess). |
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Police take special classes on how to use their cars as rams
(the most common technique is called the PIT maneuver),
and a variety of aftermarket 'cop bumpers' exist to
facilitate such actions. |
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