Bumper Rules

[TJP123]

Originally Posted by coachm

I am concerned about our bumper plan... what do you guys think? Will this pass muster?

If I'm reading the drawing correctly, and it's entirely possible that I'm not, I see three problems:
1) The right-most portion appears to be below 4"
2) The part that's 5" high isn't close to 8" wide
3) The part that's 8" wide isn't close to 5" high

The bumper has to be in the bumper zone, 5" high, and 8" long, all at the same time; not satisfying each criteria all in separate places.

But I'm not an LRI, nor did I sleep at a Holiday Inn Express last night.

[GaryVoshol]

How are you going to fill in the corner joint per R24? See the "NOT OK" vs. "OK" in Figure 4-8.

[BethMo]

I may be misunderstanding the picture. If you're planning to have no bumper along the part of the frame above the red triangle labeled "remove", then you're not legal. The bumpers need to cover 8 inches from each corner.

[coachm]

OK. Here's one version that may be more clear. We mocked up cardboard as the actual bumpers. Our mentors are reading the rules like R24 and Figure 4-8 as being top views specifically and that leaves wiggle room for what you see from the sides. Example, the top area that is decidedly less that 8" is ok, because from the top view the bumper does extend 8". This is an area that we are arguing about. We also have a mockup version where that area is filled in, but our bumpers will be frickin' enormous! LOL. The red outlined bit of aluminum plate will be removed, and the metal edge will be behind the wheels from the front view, behind bumpers from the side.

[GaryVoshol]

While that piece of cardboard with the red tape may be 8" long, it certainly doesn't look like an 8 x 5 inch piece of plywood. I don't think it's going to fly unless you can explain how it meets R21.

[coachm]

There's a plan for a piece of aluminum framing that will back the 8"x5" (currently flappy) bumper piece. It's not installed yet as there are problems with the lift that will attach to it. So there will be a piece of metal frame, then a 5x8" plywood backing with that portion, so I don't see how that part is not compliant with R21. It's entirely possible I'm missing something, though.

[BethMo]

a) The blue section, on front of robot, seems very standard -- 8 inches long, normal bumper construction, within bumper zone. I'm assuming there's a matching section (not shown) on the other half of the front.

b) Green section: If the cardboard piece is meant to represent the shape of the bumper, then it doesn't meet the cross-section requirements shown in Figure 4-7 in the rules.

[rich2202]

Bumpers are 5 inches high. The 8 inch rule has no requirement of one continuous piece. So one high piece, and a second low piece, that are abutted and total at least 8 inches, may work.

[TJP123]

Originally Posted by coachm

OK. Here's one version that may be more clear. We mocked up cardboard as the actual bumpers. Our mentors are reading the rules like R24 and Figure 4-8 as being top views specifically and that leaves wiggle room for what you see from the sides. Example, the top area that is decidedly less that 8" is ok, because from the top view the bumper does extend 8". This is an area that we are arguing about. We also have a mockup version where that area is filled in, but our bumpers will be frickin' enormous! LOL. The red outlined bit of aluminum plate will be removed, and the metal edge will be behind the wheels from the front view, behind bumpers from the side.

Read strictly as a top view, that might fly, but the rule also is very strict about the cross-section. The most generous interpretation I could give, paying attention to the cross-section, would be a high section that meets the criteria (but by itself is less than 8"), abutted to a low section does meet the criteria. I don't interpret that high-low bumper to meet the rules, but I'm not the one you have to convince.

Where you're clearly out of compliance is that low section which still looks way below the bumper zone. It's approximately even with the side of the frame, which is definitely lower than the midpoint of the wheel. Unless those are 10" wheels, I don't see 4" of clearance.