Slanted Bumper Ends

[cmrnpizzo14]

I have looked through the rules several times today and I can't find anything that would prohibit this.

Can we slant the ends of our bumpers around a gap in the frame? It would look like this

____________ ............. ________________
____________\ .......... /________________|

Nothing would go where the periods are

I think that it is legal, but I really am not sure because I can't remember seeing any robots that were like this in the past.

Any thoughts?

I will be doing a Q&A for this, but CD is usually quicker.

EDIT: The rough diagram is the top view.

[Siri]

This is essentially Q209.

Q: Would any variance to the cross-section be permitted in the spaces between the conforming sections? i.e. along the perimeter length where a design would require a gap in the bumper, would a partial (less than 5" tall) section be allowed instead of no bumper at all?

A: No. All BUMPERS must be constructed to the specifications of Section 4.1.6.

The entire length of each bumper must conform to the cross-section depicted in Fig 4-4. (A130: All BUMPERS must be constructed as described in Section 4.1.6. The cross-section of the BUMPERS must always look like that in Figure 4-4.)

By this, your answer would be no.

[Bob Steele]

Short answer...
As long as the outside corners of your robot have at least 8" of bumper on either side of the corner...this is certainly legal.
i am not sure what you mean by Slanted Bumper ends..
You may NOT, in my opinion, use the bumpers functionally by changing their specifications (ie make them slanted in at the dotted portion)

Bumper specifications are given and they must be finished in the way they are described. If Bumpers play another direct role... or have some other functionality, they are not bumpers but part of the robot and would have to be contained within the frame perimeter.

Of course if you can think of a way to use a bumper (as specified and constructed in the rules) they can have a function.

i hope this makes sense... I will give an example... if you had bumpers that slanted in (or out depending on your frame of reference) last year to help the balls enter a collection system that would have been illegal. You could have an opening in them but you may not change their construction..

You could have part of your robot that slanted in... and it could look like a bumper... but it would be counted as part of the robot and have to be inside the frame of the robot at the beginning of play.

[SenorZ]

R29
BUMPERS must be supported by the structure/frame of the ROBOT (see Figure 4-6). To be considered supported:

a. minimum of 1 in. at each end of the BUMPER must be backed by the FRAME PERIMETER

This rule would seem to imply that your robot frame attached to the bumper would also need to have that angled shape. You cannot have a section of bumper hanging in air.

[cmrnpizzo14]

I'm sorry for not being clear, I believe that my question is being misunderstood. We do not intend to use the bumpers as a frisbee funnel or any actively functional purpose. We want to create a gap in the frame that will straddle a pyramid corner. With the bumpers protruding straight out from the frame the actual "usable area" of that gap will be significantly reduced because the angle will be cut off by the 3" of bumpers that stick out.

We would still have 8" of bumpers from the corners and support it legally. It would also still cover all parts of our robot that need to be covered, but we just aren't sure if slanting the ends in to create something that looks like a funnel would be legal.

Thank you!

[CalTran]

Is the slant absolutely necessary? If that part of the frame is necessary, why not make the slant inside the robot and have the bumpers straight?

[cmrnpizzo14]

Originally Posted by CalTran

Is the slant absolutely necessary? If that part of the frame is necessary, why not make the slant inside the robot and have the bumpers straight?

Yes. We want to drive up to the pyramid corner and straddle it with our robot to help line up our climb. If the bumpers were straight out then they would hit the rungs on the way up (something that we would like to avoid, climbing is difficult enough as it is). with the slanted ends, our robot will "fit" to the corner of the pyramid helping us line up and climb more smoothly.

[Siri]

Is your original post a top view or a side view?

If it's a side view, I believe you are literally asking Q209--part of your bumper (however short) is not 5" tall through its full cross section. This is illegal--the lower edge is longer than the upper edge.

If it's a top view--four front face is shorter than your back face--you would still appear to be in violation of Fig 4-4 as required by A130, but you could ask anyway. People do this for corner joints--it's the lower left image in Fig 4-5, but fig 4-4 would seem to prohibit it when another bumper is not filling the bevel to maintain the cross-section.


That said, we're driving up the corner, and just raising the bumpers got them ore than out of the way. (They only needed to be at like 3" with the position of our climb latches.) If you're trying to use them to line up, you might consider just dropping down simple guides. They could be crazy lightweight on just a servo or a cylinder, depending on how you'd need to actuate them.

[Jon Stratis]

Look at R24, specifically figure 4-4, which combines all points of the rule in a cross-sectional view. My interpretation of that rule says that you need to have the entire cross section for the entire length of the bumper in order for it to be considered a bumper. Cutting the pool noodles at an angle would not meet that required cross section.

When in doubt, ask the Q&A.

[GaryVoshol]

See this Q&A: https://frc-qa.usfirst.org/Question/...ld-a-partial-l