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Subject: RE: High tech shock absorber dreams
From: Fred Maxwell (rockbox_at_anti-spam.org)
Date: 2003-09-25


The shock absorbing material that I am most familiar with is Sorbothane and
it is far too soft (in the forms I've seen it) to function as a
shock-absorbing component in as thin a design as the Archos bumpers.
Sorbothane also has two other unfortunate qualities. First, it tends to get
sticky. Second, it will deform permanently when left sitting in one
location.

While the Archos bumpers are less than impressive in their shock-absorbing
qualities, the neoprene cases shipped with the AJBs are quite effective at
absorbing shocks. It's quite possible that the bumpers are only there to
prevent the case from being scratched or dented during normal use.

As to your comments about the iPod's lack of any obvious shock absorbtion,
the drive itself is far smaller (physically) and lighter than the one in the
Archos. The head mechanism is also much lighter. I would be willing to bet
that the drive is shock-mounted in the PCMCIA assembly and that, even if it
is not, that it has a much higher G-tolerance than does the conventional
laptop drive in the AJBs.

Regards,
  Fred Maxwell

> -----Original Message-----
> From: owner-rockbox_at_cool.haxx.se
> [mailto:owner-rockbox_at_cool.haxx.se] On Behalf Of LoveLearn
> Sent: Thursday, September 25, 2003 1:50 PM
> To: rockbox_at_cool.haxx.se
> Subject: High tech shock absorber dreams
>
>
> Archos products have four deformable plastic wrap-around
> corner bumpers apparently present for mechanical impact
> protection. I'm sure they increase impact measurements
> necessary to damage both spinning hard drives and
> comparatively less elastic outer cases. While their
> appearance causes a few negative aesthetic opinions, even
> Archos seems quiet about their shock protecting capabilities.
> That makes me think their design and material selection were
> never optimized.
>
> I'm sure lots of us have seen TV demonstrations showing an
> egg dropped onto a hard surface and breaking, then another
> egg dropped from the same height onto a little blob of super
> shock absorbing material lying on that same surface without
> breaking. As I understand it, this material flows very slowly
> from it's own weight, but when subjected to fast impacts, has
> a very unusual break away and recovery resistance curve that
> limits peak accelerations, converting impact energy into
> heat. When I first saw photos of an Archos product so
> obviously featuring their bumpers, my hopes rose. For some
> reason I put these two complementary bits of information
> together, hoping this high tech product was the first to use
> really high tech bumpers. The fact that Archos bumpers so
> dominate their appearance reinforced these happy suspicions.
> I hoped Archos bumpers contained this remarkable shock
> absorbing blob material inside an elastic, puncture resistant
> outer skin that would slowly restore any impacted bumper to
> it's original shape after it saved the device from
> potentially catastrophic impact acceleration. That describes
> how I think truly high tech shock absorbers should be designed.
>
> I admit that I had no reason to think Archos had done this
> other than my thought that this is the obvious way to create
> really effective high tech bumpers for devices like Archos
> products. I'm just sharing my recurrent feelings of
> disappointment that the Archos design team created ordinary
> bumpers rather than extraordinary ones. I think new personal
> electronic packages should be protected with bumpers using
> the design I just explained.
>
> Current competing product makers just ignore Archos bumpers.
> But if they had my bumper design, I think comparative drop
> tests showing I-Pods et. al breaking in their own equivelant
> ways to those eggs in the TV demo, while a high tech bumper
> protected product survived over and over from the same drop,
> bumpers could no longer be ignored as a competitive feature.
> Thoughts? John LoveLearn
>
>



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