wedge as part of bumpers

[BotDesigner]

Would mounting a wedge underneath the bumpers as a hard bumper part be legal? We found our robot couldn't cross the rock wall with the new dimensions late in the build season, and we need some extra clearance on the front of the robot to make it over.

R21
...
G.
must attach to the FRAME PERIMETER of the ROBOT with a rigid fastening system to form a tight, robust connection to the main structure/frame (e.g. not attached with hook-and-loop, tape, or tie-wraps). The attachment system must be designed to withstand vigorous game play. All removable fasteners (e.g. bolts, locking pins, pip-pins, etc.) will be considered part of the BUMPERS.

So, if the wedge doubled as a bumper support this would appear to be legal. Of course the wedge would have to be in the bumper zone and extend no more than 1in from the frame perimeter.
The picture is here:http://www.chiefdelphi.com/media/photos/43107

[Jon Stratis]

The only place to get a usable answer is the official Q&A. Personally, I think this pushes things a little too far. That ramp part doesn't really seem to serve any purposes for attaching the bumper to the robot, it's just there to help with game play - that is not the intent of the bumpers or the bumper rules.

[alicen]

Future reference, you could have combined this thread with your other one

Based on what I saw with your picture, I don't believe this would be legal.

The wedge you describe as a bumper support isn't actually supporting your bumper at all, and is not legal with the very clear way that FIRST has called for bumpers to be designed.

The "wedge" as you have it is also becoming your new frame perimeter, so that makes the placement of your bumpers illegal.

[jvriezen]

Originally Posted by Jon Stratis

The only place to get a usable answer is the official Q&A. Personally, I think this pushes things a little too far. That ramp part doesn't really seem to serve any purposes for attaching the bumper to the robot, it's just there to help with game play - that is not the intent of the bumpers or the bumper rules.

I'm just a lowly RI, and Jon is my state's head LRI, but I'd interpret the rules differently-- in your favor. The wedge (assuming it resides above 4") can also be viewed as strengthening the bumper mount assembly, since it helps prevents bending of that piece and the attached bumper.

We are allowed to choose bumper fabric to assist in game play (slippery to avoid defense, friction to help play defense) and bumper height, horizontal bumper coverage to allow support or clearance for manipulators etc. Why can't I design a bumper mount system that also optimizes game play?

In 2012, we specifically used 1/8th steel sheet bumper mounts that ran the length of the bumper backing board and sized the height of the steel specifically to approach the 20lb max bumper weight (to help lower CG) it was very much overkill for a robust mounting system-- however they also strengthened the overall bot frame (which was made of birch plywood). Any bumper that has extra fasteners to the frame will help make the frame/bumper system more robust, as does this one.

As Jon says, use Q & A, but I suspect you'll get a non-answer, and they will defer to your inspector/LRI.

Hence, you may want to consider a 'safer' solution that is not so open to interpretation.

P.S. It's refreshing to see a Bumper post that doesn't have "8 inches" in it somewhere.

[Jon Stratis]

Originally Posted by alicen

The "wedge" as you have it is also becoming your new frame perimeter, so that makes the placement of your bumpers illegal.

that depends what the wedge is attached to - if it is a permanent part of the ROBOT, then yes. If it's . Part of the bumper, then no. This is the same way that brackets or the optional aluminum angle on top/bottom of the bumper (as illustrated in figure 4-7) does not count towards your frame perimeter.

This really is just a question as to what constitutes a legal fastening system, and are features that do not impact how "rigidly attached" the bumper is legal?

[engunneer]

R21A also has something to add to this. I think if your hard parts were 5.5" tall and had a chamfer at the bottom edge, and you managed to get your fabric attached to it, it could potentially be legal. As drawn, not so much.

[rich2202]

Short answer is: No.

Long answer: If it is part of the Bumper: No. The Bumper is the Bumper and must follow the Bumper rules. A wedge is not a valid Bumper design.

If it is within your frame perimeter and attached to the Robot, then it is ok.

[Eric Scheuing]

At Waterbury, we discovered our bumpers had a 1/4" gap between the front of the bot and the frame. We called the lead inspector over to discuss legality, and he said that we would need to put a piece of material in there for it to be considered fully supported. What's more, he said that if it mounted to our bumper, it would not count against our frame perimeter.

Long story short, do what everyone else is saying and mount it to your bumper. It shouldn't count against your frame perimeter.

Ninja Edit: Make sure it's easily removable in case the inspector has an issue with it though.

[Ryan_Todd]

Originally Posted by jvriezen

...The wedge (assuming it resides above 4") can also be viewed as strengthening the bumper mount assembly, since it helps prevents bending of that piece and the attached bumper.
[snip...]
As Jon says, use Q & A, but I suspect you'll get a non-answer, and they will defer to your inspector/LRI.

Hence, you may want to consider a 'safer' solution that is not so open to interpretation...

Agreed on all counts!

In particular, that gap between the top of the wedge and the bottom of the wood is the biggest reason why one would question the legality of this design. All you need is to slide the remainder of the bumper assembly down until it bumps into the top of the wedge, and the wedge becomes an indisputably integral (if somewhat unconventional) reinforcing member of the bumper assembly.

in other words:
________
|| . . .\
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|| . . . |
|| . . . |
|| . . . |
||______/
|
| <---- questionable gap
|__
| /
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becomes

________
|| . . .\
|| . . . |
|| . . . |
|| . . . |
|| . . . |
|| . . . |
||______/
| / <---- definitely part of the bumper
|/