A bumper design question.

[Garrett.d.w]

Hi,
I have been looking to mount the rear bumpers on the bot. However, we have a series of bolts (two) that extend 3/4 of an in beyond the frame. As of now, I was considering drilling corresponding holes in the bumper backer, allowing the bumper to sit flush against the frame (with the bolt ends inside the bumper).

Would this be legal? I searched through Q/A as well as the rules and couldn't find anything relating to the topic. I do feel, however, that I might not get a response from Q/A (design review rather than a rule clarification).

I can answer clarifying questions, provide pics, etc.

Thanks

[bgg]

Drill the clearance holes in the plywood so it sits flush against the frame. If questioned just tell the inspector I said it was ok. I can't quote exact ruling but we've used the method on teams for years. Just be sure the holes don't compromise rigidity or other rules.

[Gregor]

Originally Posted by bgg

Drill the clearance holes in the plywood so it sits flush against the frame. If questioned just tell the inspector I said it was ok. I can't quote exact ruling but we've used the method on teams for years. Just be sure the holes don't compromise rigidity or other rules.

That isn't how it works.

Me: But Mr. inspector sir, some person on Chief Delphi said it was ok, pass me!
Inspector: Incorrect

[Alan Anderson]

"Pocketing" the bumper backing to accommodate minor protrusions beyond the frame perimeter is okay. However, <R02> says such protrusions cannot be more than 1/4 inch. Your bolt heads go beyond that, so they'll end up defining the perimeter.

If you can't move the bolts, I think a good option at this point is to add a 1/2"-thick "shim" to the side of the frame where those bolt heads are. It'll add an inch to your perimeter measurement, though.

[Garrett.d.w]

Originally Posted by Alan Anderson

"Pocketing" the bumper backing to accommodate minor protrusions beyond the frame perimeter is okay. However, <R02> says such protrusions cannot be more than 1/4 inch. Your bolt heads go beyond that, so they'll end up defining the perimeter.

If you can't move the bolts, I think a good option at this point is to add a 1/2"-thick "shim" to the side of the frame where those bolt heads are. It'll add an inch to your perimeter measurement, though.

Yeah, I figured that would be the case. I designed the robot to fit within 112 in frame perimeter rule with those bolts, so its not a problem to add the shim.

Thanks.