Whats the Best way to do Bumpers?

[BJC]

During our Monday meeting my team got to talking about last years bumpers. We concluded that although our bumpers worked quite well, there were better ways to do them. I was charged with finding a past thread on the subject if one existed, and starting a new thread in the event that it didn't. I didn't see one so here goes...

I'm basically wondering:

1: How did your team do your bumper mounting or otherwise? (I know there is that very cool flip method.)

2: What was the best bumper mounting you saw during the season, I'm talking about either functionality or looks. (on the killer bees we're all about looking good.)


To get the discussion rolling: my team made pretty standard bumpers which attached to the frame via 1" aluminum L bracket and some... I'll call them easy bolts for lack of a better term as they could be screwed and unscrewed quickly be hand. However, we had 8 different bumper parts which were kind of cumbersome. (4 red 4 blue)


Thanks in advance, this will be a great help.

[Radical Pi]

We used 2 L-brackets per attachment point (2 or 3 points on each bumper). There were holes drilled through the outward part of the L-brackets as well as through our robot's frame. To attach the bumpers, they were placed on the frame and then pins (basically these) were placed through the holes so that the pin went in the top bracket, through the frame, and out the bottom bracket.

For color of bumpers, we attached snap buttons to the bumper and to our blue fabric, which allowed us to go from blue to red almost instantly with one person per bumper (red to blue was obviously harder).

This system allowed us to switch from red to blue in < 3 minutes with a 4 person crew. Took one person to remove each bumper (we had 4), then each person could attach the blue fabric, then it would take 2 people to put each bumper back on (one pushing it in, the other placing the pins).

[Jeff Pahl]

If you are using the kit frame material, I highly recommend the bumper brackets that are sold by AndyMark. They slide right over the frame rails and you drop a hitch pin or bolt through the holes. About 30 seconds to remove or replace a bumper. They are not cheap, especially if you are making 2 sets of bumpers, but are worth the investment.

The same technique can be used for non-kit frame rail materials, if you have access to a metal brake or a sponsor that can bend you some. One of my teams did that a couple years ago with great results. Or find some channel the right size and use that. That can also be done with the kit frame.

I'm not a big fan of permanently attached bumpers, I strongly recomend a solid, well thought out method that allows them to be removed and replaced easily. Keep in mind that the rules recommend that one person should be able to do the task in under 10 minutes. Also keep in mind that the bumpers have to be off the robot for weighing and sizing. You would not believe the number of robots that it takes an hour to try and put the bumpers back on.

When I give seminars, I emphasize that the bumpers need to be part of the design from the beginning, not something that is hacked on to the robot on ship day or at the regional. It's very obvious when inspecting a robot if this was the case or not. If you pay attention to what you are doing, that 3/4" slab of plywood can provide a lot of structural integrity to a lighter weight frame.

Also, if you are only going to have one set of bumpers, and looking good is important to you , making slip covers for each bumper that attach with snaps or velcro and fit snugly is strongly recommended. The elastic covers that were available last year came loose or got pulled off due to robot-to-robot interaction. Saw some penalties due to the bumper cover hanging down below the bumper zone. Duct tape and/or cable ties are not an acceptable method of trying to hold the cover back on. I know it's a pain to have to store them in the pit, but I recommend having two sets so you don't have to worry about covers coming off.

[AustinSchuh]

Originally Posted by Radical Pi

To attach the bumpers, they were placed on the frame and then pins (basically these) were placed through the holes so that the pin went in the top bracket, through the frame, and out the bottom bracket.

We had two sets of bumpers, with a very similar attachment method to this. We used the same pins, but used 1" ID C stock and put that around 1" x 2" tube stock. We then drilled a hole through both pieces of metal, through all 4 walls. We then dropped the pin through the hole. We could take a bumper off in 5 seconds, and put another one on in 15 seconds. If we have bumpers again next year, that's how we are going to do it again.

[Rosiebotboss]

All these methods work well. BUT, the VERY BEST way to construct and mount bumpers is in strict accordance with the 2011 FRC Manual.

[BrendanB]

Originally Posted by Rosiebotboss

All these methods work well. BUT, the VERY BEST way to construct and mount bumpers is in strict accordance with the 2011 FRC Manual.

Best or easiest? I'd go with easiest for bumpers any day.

Our team attached our four bumpers together with angle brackets to make one large bumper and then had corner plates that laid horizontal to the top of the robot frame and attached to the robot with wing nuts. Took 2-4 students around 20-30 seconds to install.

[kgzak]

Originally Posted by Rosiebotboss

All these methods work well. BUT, the VERY BEST way to construct and mount bumpers is in strict accordance with the 2011 FRC Manual.

You want to get me a copy of this rule book?

[EricH]

Originally Posted by kgzak

You want to get me a copy of this rule book?

Can do, but due to circumstances beyond our control, it will not get to you before January. It will have the bumper instructions, though.

[joeweber]

We countersunk 2 "U" chanels into the plywood for the bumpers than wraped the fabric around it. The "U" chanels slipped over the frame we than slipped eye bolts through drilled holes and install wing nuts. This allowed us to remove and install with out tools.

I wonder if we can use the same bumpers for next year? That would save some money and work.

[davidthefat]

Was the bumper necessary every year? or was it just last year? Was the bumper as limited as last year was?

[EricH]

Bumpers are required and have been since 2008. They were optional in 2006 and 2007. You must use the pattern given in the rules, and yes, they are that limited, though openings are typically allowed.

[Siri]

We were a wing-nut bumper team this year as well. It started out very fast and got progressively more difficult as our additional functionality started blocking hand access. Still a clean and simple system and much better than some of our previous methods.

My favorite technique? Probably these guys. Then again, it's hard to beat the Thunder Chickens and their rivets.

[rahilm]

As far as construction, we just took the wood, glued on pool noodles, put the fabric around it, and stapled on the back end.

For mounting, we used 254's slick idea of codder pins. Took us about 10 seconds to replace a single bumper (total of 4 bumpers). After one competition, we made it a requirement that each drive team member carry an extra codder pin on them at all times

[EricH]

Originally Posted by joeweber

I wonder if we can use the same bumpers for next year? That would save some money and work.

Chances are, you won't be allowed to. They'd be fabricated items used on a previous robot, thus not allowed under the 2010 rule <R35>. Assuming that the 2011 rulebook has the same rule, which is in fact a pretty safe bet (it's been in the rules for as long as I can remember), then no use of this year's bumpers would be allowed.

Also note that robot design plays a factor; your robot design next year may not call for bumpers all around the perimeter.

Standard disclaimer: I am not on the GDC, and therefore have no knowledge of the game, and this is an unofficial forum, so this is not to be construed as an official statement in any way, shape or form.

[GaryVoshol]

Even if the rules would allow reuse of the bumpers, you'd be wise to look at making a new set. They get pretty beat up over the course of a year, especially if you go to several events and off-season events. The pool noodles begin to compress, and the wood starts to splinter and even crack. Besides, don't you want a fresh look for your new robot each year?