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Unread 04-01-2009, 01:08
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Tristan Lall Tristan Lall is offline
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Re: New Bumper Rule makes West Coast drive Illegal?

Quote:
Originally Posted by Kevin Sevcik View Post
If I were an inspector, I don't think I'd be passing any robot claiming at something classified as a "strip" was somehow a structural frame member.
That's exactly why it's hazy, though: let's say I use a 0.19 in thick × 1.00 in tall strip of polycarbonate as the backing material, with several screws into the bumper plywood. Will it be strong enough across a 20 in span? My gut feeling is that under most gameplay, it would not break, or even deflect appreciably. But what if the team used (brittle) acrylic instead? Or if they turned the strip 90° to buttress the plywood? I don't think it makes much sense for inspectors to be trying to make that particular determination—it will just be their best guess, and it's ripe for debate that serves no useful purpose.
Quote:
Originally Posted by Kevin Sevcik View Post
The intent here is to prevent bumpers from possibly snapping in half, etc. under repeated impacts. I submit that if the "frame member" behind the bumper isn't going to protect your robot in this event, then it probably doesn't count for this rule.
If your bumper plywood ever breaks, even with no backing (and especially with the aluminum angle depicted in Fig. 8-1), you're probably doing it wrong. And if you use high-quality hardwood marine plywood (as opposed to the regular softwood stuff), you could probably span over 30 in without any backing, and suffer no ill effects.

I just don't think it's valuable to add a specification here, given that it's one more thing for teams to worry about, one more thing that needs to be checked (consistently) at inspection, and is probably superfluous anyway, given moderately-well-constructed bumpers.