How to build good bumpers

[kyle_hamblett]

I figured in light of Frank recently confirming the return of bumpers, I would see what other teams have done in the past that has worked, and maybe what has not worked regarding good bumpers. For 2014, 1073 used hinges , some c-channel, and a few pins that we could swap out fairly quickly. The only problem was that the hinges weren't all that great, and IIRC, they were constantly loose.

[SerpentEagle]

I know that either 1114 or 254 (I cant remember) uses a special low friction material to slide by opponents during pin-holds.

[EricH]

Originally Posted by SerpentEagle

I know that either 1114 or 254 (I cant remember) uses a special low friction material to slide by opponents during pin-holds.

I believe 254 uses sailcloth or something similar.


The biggest thing with bumpers is to get the fabric nice and tight. What some teams will do is to staple (or otherwise secure) one side of the fabric, then have several people stretch it over the noodles and hold it while someone staples the other side down.

[Chris is me]

Tape your noodles in place before you wrap the bumper. This helps a lot in the assembly process and especially helps prevent sagging noodles.

Staple one side, then stretch the fabric as tight as you can before stapling the other side. Any amount of sag in the bumper is bad.

Remember that your bumpers can (by 2014 and previous rules) weigh up to 20 pounds, and there's no reason you can't make your structure that you use to mount the bumpers as beefy as you would like.

[TheHolyHades1]

Originally Posted by Chris is me

Remember that your bumpers can (by 2014 and previous rules) weigh up to 20 pounds, and there's no reason you can't make your structure that you use to mount the bumpers as beefy as you would like.

For reference, our standard set of plywood bumpers mounted with wood tee nuts weigh somewhere around 12 lbs, so there is a lot of room to grow.

[dubiousSwain]

The Lunatecs have recently made reversible bumpers out of thick fabric and velcro. Basically the red and blue fabric is sewn together on one side and then again in the middle. The free ends are then stapled to the backboard. Volia, you add velcro and you have a single set of bumpers that can be used for both (or all 3) alliances.

[GeeTwo]

Another trick used to get the bumpers tight is to compress them before stapling. Some teams report using a custom device they made, but we just used our three large (10"?) c-clamps and a table top, and do one edge at a time.

Securing bumpers them with angle brackets works well, as long as you have an inch or more of bumper above the top of your frame perimeter. Mount two bolts to each side of the chassis facing up (should be easy with the KoP chassis; just use the holes already there), drop the bumpers over the robot into place, and secure with a second nut on each bolt. (Wing nuts or power nut driver recommended). Rivet nuts mounted in the frame and (captive?) bolts passing through the bumper's brackets could probably also be used for this, but we haven't tried it.

[Chris is me]

Originally Posted by GeeTwo

Another trick used to get the bumpers tight is to compress them before stapling. Some teams report using a custom device they made, but we just used our three large (10"?) c-clamps and a table top, and do one edge at a time.

Securing bumpers them with angle brackets works well, as long as you have an inch or more of bumper above the top of your frame perimeter. Mount two bolts to each side of the chassis facing up (should be easy with the KoP chassis; just use the holes already there), drop the bumpers over the robot into place, and secure with a second nut on each bolt. (Wing nuts or power nut driver recommended). Rivet nuts mounted in the frame and (captive?) bolts passing through the bumper's brackets could probably also be used for this, but we haven't tried it.

By the 2014 rules (and specifically the Q&A), pre-compressing your bumper noodles as you assemble them isn't legal. I'll find the actual rule after work, but I remember this being shown / proposed in a CD thread in 2014 and a Q&A ruling came in declaring it illegal. Sorry for the vagueness.

[Jon Stratis]

Originally Posted by Chris is me

By the 2014 rules (and specifically the Q&A), pre-compressing your bumper noodles as you assemble them isn't legal. I'll find the actual rule after work, but I remember this being shown / proposed in a CD thread in 2014 and a Q&A ruling came in declaring it illegal. Sorry for the vagueness.

From 2014:

Q302
Q.R21 C states that teams should use a pair of 2.5" pool noodles. Does that requirement refer to the pool noodle's size when on the robot, the pool noodles size when purchased, or both? Is compressing pool noodles legal?
A.1) Both. 2) No.

Please note that while previous answers like this may provide guidance on the general thinking towards a rule area, unless/until it's asked for this season, there is no official ruling that applies for this year. Which means you may or may not be flagged for it by an inspector if it's not crystal clear in the rules/q&a for this year.

[MooreteP]

Originally Posted by dubiousSwain

The Lunatecs have recently made reversible bumpers out of thick fabric and velcro. Basically the red and blue fabric is sewn together on one side and then again in the middle. The free ends are then stapled to the backboard. Volia, you add velcro and you have a single set of bumpers that can be used for both (or all 3) alliances.

This^

It's more work during the build, but it is so worth it at competitions.

You will need a heavy duty sewing machine to work with the sailcloth.

[MrBasse]

Totally agree with reversible bumpers. Why have a quick change bumper when you can just flip the color around even faster.

https://www.youtube.com/watch?v=XYTiRxLw7oA

[natejo99]

Originally Posted by dubiousSwain

The Lunatecs have recently made reversible bumpers out of thick fabric and velcro. Basically the red and blue fabric is sewn together on one side and then again in the middle. The free ends are then stapled to the backboard. Volia, you add velcro and you have a single set of bumpers that can be used for both (or all 3) alliances.

Team 74 did the same thing in 2014. It was pretty convienient at competitions.

[jwfoss]

In my mind the reversible bumpers and bumper covers teams have produced in the past never looks as "polished" as separate well made bumper sets. The key to good looking bumpers? Pick quality materials (plywood, noodles, and fabric) and take your time.

[philso]

Originally Posted by jwfoss

The key to good looking bumpers? Pick quality materials (plywood, noodles, and fabric) and take your time.

Yes. Plywood. Get the good, sanded both sides stuff, not the sheathing grade that is rough. It's only a few dollars more.

In 2014, someone decided hardwood planks (oak or maple, I think) would be suitable. They ended up splitting along the grain in several places.

[MrBasse]

Originally Posted by philso

Yes. Plywood. Get the good, sanded both sides stuff, not the sheathing grade that is rough. It's only a few dollars more.

In 2014, someone decided hardwood planks (oak or maple, I think) would be suitable. They ended up splitting along the grain in several places.

Why used sanded material when the other material works just as well and you'll be covering it up? That's like using high polished material when you plan on painting it anyway. Price difference is small ($19.18 vs $26.58) but I just don't see the point, does smooth plywood hold staples better than rough plywood?

And I think the rules have specified plywood for as long as I've been making bumpers, so hardwood shouldn't even be considered anyway. Plywood will take an impact better due to the crossing grain structure over hardwood, the results of hardwood would be exactly what you stated.