I’m thinking about how I want to go about mounting the bumpers to are robot, last year we used bolts and worked but was slow. I was thinking about using aluminum rivets and then just drilling them out (would be fast since there aluminum) has any one ever done this or thought about it?
Wing-nuts would be definitely faster, and would prevent swiss-cheese from repetitive drilling
Would you recommend the bumper mounts included in the KOP
1895 recently switched to using bumper latches, almost identical to the ones that 2363 uses (but adjusted to fit our standard chassis). I would recommend trying these out, since it makes switching out bumpers super fast and efficient. They have also proven rather durable, and we haven’t noticed any issues with them after our first competition.
Same goes for 3244. We saw this video and ordered them right away. it was a unanimous vote from the whole team. Last year we had used wing bolts and it took a 45ish seconds to swap bumpers. switching to these is now around 15 seconds.
Would they work on this years frame
We use t-handles like these: https://www.amazon.com/gp/product/B00GAZ5BDK/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
Pretty simple, you just make a U bracket that goes around the frame, stick it on the frame and drill straight through the whole thing with a .257" bit (“F”). They work even if you need to slop the holes a bit to get everything to fit. Never had one come out during play, and 1 person can swap all 4 bumpers in about a minute.
We use a bracket system we developed for Steamworks because the team members were getting their hands chewed up trying to put in and out the thumb screws we were using to mount bumpers through the frame. The system uses ABS sockets that we mill out using a table saw, cut down 5" angle iron brackets, and 1/4" hitch pins. The bumpers are C-shaped, with two smaller brackets on the inside of the C and one pin bracket on each leg of the C. The plastic sockets are installed on the top of the frame so that the side brackets slide straight into the C-shaped side sockets and the two pin brackets slide sideways into the L-shaped sockets, which have matching holes for the hitch pins. The result is a system that we can install and remove in 10-20 seconds without tools, but is extremely solid when the pins are in.
Here are pictures of the system as it was installed on our Steamworks bot:
I would avoid any method that requires drilling out rivets for the following reasons:
- its slow
- the holes will end up oversize and the rivets sloppy
- you are producing electronic killing conductive shavings that you have to deal with
There are many retains pin type systems (R clips, T pins, Hitch pins etc) that allow for fast fastener free changes. I would strongly suggest considering one of them if you want to get away from nut/bolt systems. Even Wing nuts and captive studs speeds up the process.
we are using the mounts that come with the KOP so a stud wouldn’t work
Determine the size and depth of your hole through the bumper bracket and frame. Perhaps a correctly sized lynch pin would suffice.
What holds the Linchpin in place
Linchpins typically go through the shaft they are securing and then the ring folds over to retain the pin. Could also go with some kind of detent pin. Simple ones are retained by a spring loaded ball, fancier ones use an internal spring/piston setup to manage the ball (similar to the system used on many socket ratchets).
Given that R27 requires easy install/removal (2 people 5 mins) and R31.G requires an attachment system designed to withstand vigorous game play. As an RI, It would take a lot to convince me that a mounting aluminum rivets could meet both of those rules.
Not that I am in any way advocating for riveting your bumpers on, but if they are in contact with the frame, there is very little load on the actual mount in most impacts, as all robots have the same type bumpers at the same heights. The loads are almost all in compression, and transfer to the frame via the bumper/frame contact patch rather than through the mounting system.This is especially true if you have wrap around bumpers that don’t have exposed edges to get caught, which would apply shear loads.
Having done the racing pitstop type repairs on damaged robots, back when we used a lot of rivets, you certainly could do it with 2 people in less than 5 minutes. The question is why would you subject yourself to that match after match when there are so many better solutions.
Our current solution is mounting posts and R clips. Even if we go robust and put in all five pins per bumper (U shaped bumpers with pins front, back and 3 on the side), it is under 2 minutes for 1 person, if they are not rushing. Often we only put in 3 clips/bumper. If we are in a hurry it is done with 2 people. Zero tools, easy to do in the queuing line, clips don’t roll away when you drop then, can’t vibrate loose.
I was thinking you could use the pin instead of the bolt.
After looking around I think that @Jon_Stratis has the best quick solution for this…
Not sure of how long of a grip length you need on the KOP drivebase, Our last KOP frame was in 2011 and they were very very different.
Here is perhaps a better size to sneak in. You need to verify the grip length.
The base has changed, but back in 2013 we used these ones with the AM14U3:
3.75", went all the way through the frame, and through the bumper support material on top and bottom (1" angle brackets that year, I believe)
DEFINITELY Yes, it makes life a ton easier and also if your bumpers go through rough beatings or crashes they aren’t likely to break
We had reversible bumpers last year and used aluminum rivets it was terrible. Slow to remove during inspections. When they had to be removed over the season the holes expanded from all the removing as the students over drilled or accidentally picked up a 1/4 inch bit instead of a 3/16th. We moved to bolts with wingnuts this year and it’s a breeze.
We ended up mounting L Stock on the bumpers with a hole on each end so when we drop the bumpers on the frame a bolt will go thru them and we thread a nut on