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Unread 03-02-2010, 19:23
sanddrag sanddrag is offline
On to my 16th year in FRC
FRC #0696 (Circuit Breakers)
Team Role: Teacher
 
Join Date: Jul 2002
Rookie Year: 2002
Location: Glendale, CA
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Re: Fasteners extending outside the FRAME PERIMETER

Paul, I think what Dave was trying to say, is that even by the original rule, if your frame perimeter consisted of a piece of metal, with a row of rivets heads on it, this would not meet the requirement to fully support the bumper along its length, since it is supported at only at the rivet heads. So, in this type of a design, a shim/spacer would have been needed all along anyhow, before any updates. Although, I suppose if small indentations were made in the bumper backing to clear the rivets, the bumper would have been supported by the metal which is inside the (as previously defined) frame perimeter, not at the frame perimeter itself.

And let's think about the following too. In theory, any member defining the frame perimeter that is not perfectly planar does not fully support the bumper. There exists no such surface.

So the question becomes, what is the maximum allowable space between the bumper backing, and the frame perimeter, for which the bumpers shall still be considered "fully supported." I would argue up to a 1/4 inch should be deemed acceptable. Materials and manufacturing methods have a tolerance...

Silly, I know...

Something needs to be done to make this all simpler for everyone. Maybe I'm looking at this wrong, but I have been in FIRST for 9 years now, and I still can't figure out how I would explain this rule to anyone. Let's also remember that many inspectors have never even seen a FIRST robot before. This will never work.
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Teacher/Engineer/Machinist - Team 696 Circuit Breakers, 2011 - Present
Mentor/Engineer/Machinist, Team 968 RAWC, 2007-2010
Technical Mentor, Team 696 Circuit Breakers, 2005-2007
Student Mechanical Leader and Driver, Team 696 Circuit Breakers, 2002-2004

Last edited by sanddrag : 03-02-2010 at 19:30.