What type of bumper mounts do different teams use?

Was trying to find new ways to mount bumpers, as ours is slow and sometimes a handful. We use 1/8" brackets that attach to bolts on the chassis and the bumpers are secured to the robot with wingnuts.

254 bumper mounting and west-coast-drive frame design was discussed here:

2 Likes

While I haven’t used them personally, I’ve heard awesome things about this style of latch. We’ll very likely be giving them a try either this off-season or during the 2023 season.

We have used these before and I would not recommend. Bumper changes are super quick, but there are some drawbacks. If you do not pay attention and have all the latches open when putting bumpers in you can bend pieces on the sliding part is the latches. Also hard hits can cause the latches to pop out of the groove and a loose bumper on that portion of your bot.

We never fully lost a bumper in a match with these, but had a few uncomfortable moments.

We moved back to a simple captured nut and l bracket mount. Takes a bit longer to swap, but can still be done in less than a min with two students.

3 Likes

Here’s a link to an old post with lots of explanatory pictures from 2019 on 4829’s bumper mount system. We developed this during the Steamworks season and have used it ever since. It basically uses angle plates screwed to the backs of the bumpers that fit into machined HDPE or ABS mounts on the frame, with the ends secured by hitch pins through the mounts and angles and into the frame. It’s extremely secure when installed but can be changed in less than 30 seconds by just pulling the pins and pulling the bumpers away from the frame, then reversing that with the other bumper set. We used to cut the plastic mounts on a table saw (literally kerfing out the recesses for the angles) but now we cut them on our CNC router and do the whole batch at one time. It can be adapted for almost any frame style (the pictures are of our Steamworks bot, which had a kit frame) and the angles are usually just 4" angle irons from Lowes with one arm cut down (the hitch pins come from Lowes too.) We’ve seen many other systems since, but this one works so well for us we’ve stuck with it.

1 Like

At FIM states this year, using these mounts, we were hit so hard it broke a piece of our chassis, (with the bumper) but the mounts held firm. I would not have counted on that, but that’s the best test we could have given them. They’re super easy to take off and on. And they’re cheap too. (Knurled nut & R clip)

1 Like

When that hit happened I thought the bumper fell off but upon inspection it sheared all the rivets holding the framing together.

Honestly, I was going to recommend something very similar to your solution. Drop-on wrap-around or “bracket” bumpers with four wing nuts takes about one minute-person. If you insist on corner bumpers, that goes up to two minute-persons for eight wing nuts. What problem, or perceived problem, are you trying to solve?

1 Like

The problem with the stud and nut or wing nut mount is the threads always end up chewed up making the nut not spin on easily.

1 Like

Also, the mounting stud is generally recessed between the bumper and robot making it just that much harder to thread on the wing nut. We had a robots with one a inch of clearance to thread on a wing nut that was a total PITA. We no longer use wing nuts and have made bumper mount design a priority since then.

Look at jaunvie’s post they are quick easy and they retain the bumpers really good. The hardest part of it is the R pins used to come up missing since the little lanyard rope would slide off. He have rectified that problem with a little piece of heatshrink around the rope and clip. Oh and bending the R clips over to make them easier to install and pull out, little taps with a hammer in a vise works good. We also use rivnuts in the frame and a small washer under the knurled nut space it up perfectly.

We have done something similar, but we drilled out the stud and used a smaller R clip through the hole in the stud. Glad you have had good results with the method shown, but I’d be concerned with the clips popping off. We have also done something similar to what Strategic suggests above and that is what I like best so far.

1 Like

We haven’t used them yet but I saw some snazzy quick release ones by Plummer Industries in Houston at the Championships but I could not find them on their website. I was hoping someone here had used them and had some feedback.

1 Like

If anyone has pics of this setup from Plummer Industries, I’d love to see it! Wasn’t in person at Houston so couldn’t check out the vendor booths.

1745 used these southco rotary latches this year and we were really really happy with them.

Southco r4 rotary latch on the bumper. R4-05-21-505-10.
Wire Striker on the robot. R4-90-0501-10

1 Like

These look interesting, do you by any chance have any pictures of this on the robot? I’m having trouble picturing how this works.

1 Like

We normally use 8 bolts with nuts, but we make reversible bumpers so we don’t really have to worry that much about switching them. Even taking them off takes about 5 mins with 4 people.

you can see the latch attached to the bumpers here if you zoom in.
https://photos.google.com/share/AF1QipPMrLAjMv4TvxAZmA4vVqqh8SQJVp_slU0-b6saa8IP31TPuOo3ZsAHAHdKe-oxLg/photo/AF1QipM3FLyRqNj_v7-N5gegMDtVFXpJ2H9RW9w-AMhm?key=cGVoSDU2WldEaXdvQUxGQlBpdmM4UGIwNXdDbEhB

and here is the strikers on the chassis.
https://photos.google.com/share/AF1QipPMrLAjMv4TvxAZmA4vVqqh8SQJVp_slU0-b6saa8IP31TPuOo3ZsAHAHdKe-oxLg/photo/AF1QipNS3pHaIR7fDMm34l1gUPSUSHuAsQ72BKa3mNXg?key=cGVoSDU2WldEaXdvQUxGQlBpdmM4UGIwNXdDbEhB

additionally here is the CAD of the bumpers.
https://cad.onshape.com/documents/9dfac1522cee66570efd4342/w/27df8d26c6398887bc75e4b6/e/3a7553ae40abc6c5a024af40

1 Like

Very cool, thank you for sharing. So, once the bumpers are latched in, it looks like the release lever is pinned in place to prevent it from un-latching mid match? Also, how much play is there between the striker and latch once it is in place, it looks like you have the latches on the side pretty close together, did you have any issues with your bumpers rocking because of that play?