Bumper easy attachment?
 

Hey all,

I remember some user talking about some kind of clips that make attaching and taking off bumpers a complete BREEZE.

As my team and many others have gone frustrated bolting and unbolting bumpers through holes that barely line up, I wanted to bring up this topic to ask how your team (if it has) has coped with this challenge and made bumpers easy to take off and attach.

Re: Bumper easy attachment?
 

In the past our bumpers have had brackets attached to them that slide over a frame rail then we use these quick release pins to hold them in place. Just make sure the usable length is the thickness of your rail and brackets.

Edit: We use the shoulder style pins, don't know why it won't let me change the url to that page specifically.

Re: Bumper easy attachment?
 

My team prototype some bumper attachments this off-season. We use 1/4 x 1 1/2" quick release pins. We got them from our local Homedepot.

Re: Bumper easy attachment?
 

Last year we made reversible covers for the bumpers - no removal and 10-15 seconds to switch colors!

Re: Bumper easy attachment?
 

How did you weigh/size the robot?

Re: Bumper easy attachment?
 

254 and 971 used these draw latches this year. Very easy and quick to get out. Maybe someone from 254 or 971 can link the actual part number for the draw latches they used.

Re: Bumper easy attachment?
 

You only do that once per competition but you switch colors many times. The bumpers can be attached using more rigorous (but longer to install) methods.

Re: Bumper easy attachment?
 

For the past two years 1610 has used the nylon slides that are used with
20x20 and 30x30 extruded aluminium. In 2011 we made end bolted on bumpers
as normal, but for the sides we mounted four slides on the back of the bumpers
so they could just be slid to the side
off the frame. When the end bumpers were in place they kept the side bumpers
from sliding out. We had to counter sink the slides for the screws and slightly
route out the plywood so the bumper was flush with the frame.

This past season (2012) we modified that design. In stead of sliding them
horizontally we modified our frame for 30x30 vertical uprights with
horizontal 30x30 between them (this was mounted on one horizontal 30x30 piece
on the bottom.)so they could be slid vertically. We mounted
a nylon slide on each end and one in the center. It takes a little trial and
error to get them placed right so the bumper comes out the height you want.
We tapped the top end of the vertical 30x30s of the frame to accept a 5/16x 1" bolt.
We'd slide the bumper on,place
a washer on the 30x30 and bolt them down. We could change a complete set
off and on in two mins. Using this design made it a little harder to make the frame
but it saved a ton of time changing the bumpers.

Re: Bumper easy attachment?
 

To you folks, since the connection isn't necessarily rigid/bolted, what's preventing "play" in the bumpers? I'd image that if you have have a 1/4" pin into a 1/4" + some set of holes, you're going to get some play?

- Sunny G.

Re: Bumper easy attachment?
 

Sorry for not explaining well enough. Yes we did drill a 1/4 hole for a secure connection. We did a quick release pin every eight inches for all sides. It was also tested against other robots at a off-season event as well as at home against other robots. It held up with the problems and had no play what so ever. It went though a 1x1" square tubing and c-base channel on the chassis.

Re: Bumper easy attachment?
 

Our team makes one set of bumpers. We staple one colour of fabric on the bumpers and atttach to bot. We then take the other colour and sew bumper covers that we can attach using velcro. This makes changing the bumper colour super easy.

Re: Bumper easy attachment?
 

Is this the thread you remember?

http://www.chiefdelphi.com/forums/sh...ory+5+bumpe r

If this is it, feel free to PM me for details.

Re: Bumper easy attachment?
 

If I can't dig up a picture I'll do a quick drawing and post it tomorrow.

Re: Bumper easy attachment?
 

There are a few options that I would like to point you to:

1. Reversible Bumpers (http://www.chiefdelphi.com/media/papers/2437?)

-This is the method that our team used this year, and it turned out to be a huge success. My only word of advice is to make sure that your velcro mounts are secured firmly on (we ended up stapling the velcro to the fabric.

2. Quick Release Pins

-This has also worked very well for some teams, and something that our team is going to prototype within the next few weeks.

3. Latches
-This seems like a very innovative idea. I was talking to a mentor of Team 254, however, and he said that this tended to get annoying for the team to use. However, this is a great idea nonetheless to get your ideas flowing. You can find a picture of it here:
http://2013.team254.com/wp-content/u...fire-small.jpg
Also, check out their team's website for other ideas.

Re: Bumper easy attachment?
 

We too used 1/4in pins with our reversible bumpers. 10 secs to flip colors and another 30 seconds to remove the bumpers with two people.

We also had reusable zip ties to hold the pins into our frame so we would lose them and kept a tighter fit. While their was a little play they never came off and after two very strict bumper inspections they never said their movement was unacceptable.

Re: Bumper easy attachment?
 

links 3 and 4 fail, Adam. Ellipses in URLs leave out essential info.

Re: Bumper easy attachment?
 

Aahh, thank you very much. I actually just copied that from a previous post of mine, and I forgot to redo the links. It should all be fixed now. Thanks!

Re: Bumper easy attachment?
 

I did a quick sketch of what our brackets have looked like in the past. Angle stock attaches to the bumper itself while the square stock is mounted on the robot, we use this stock to build most of our frame. A drop pin then goes through all three pieces holding it in place. Usually a long section of bumper has two to three of these while a shorter bumper has two.

Since I can't get the image to upload here is the dropbox public link:

https://dl.dropbox.com/u/32389675/bumper%20bracket.png

Re: Bumper easy attachment?
 

A second set of bumper covers seems really simple and much quicker than removing and attaching a red and blue set.
Is there a problem with R28 - BUMPERS (the entire BUMPER, not just the cover) must be designed for quick and easy installation and removal?

Re: Bumper easy attachment?
 

All they are saying is it shouldn't take you a ton of time to get the bumpers off, cover or no cover.

Re: Bumper easy attachment?
 

The C shape of the bracket and tight fit on the frame rail keeps it from twisting. The vertical pin should have a tightish fit in the hole combine to create basically a box around/through the rail and keep it from pulling away. It rattles a little, but doesn't move unless you've got too much tolerance in either the bracket or pin hole. Here's some ascii art:

Re: Bumper easy attachment?
 

We take some 2"x2" aluminum angle and rip 1" off one side and drill some 1/4" holes to mount to our frame and on the other side we cut what amounts to an "L" shaped slot. Each piece is about 3" long and we usually have 3 for each side bumber and 2 for each front and back.

The bumpers have a small plate mounted to the plywood behind each bolt hole under the pool noodle. A 1/4" bolt is threaded into a tapped hole in each of these plates.

To mount the bumpers the bolts drop into the "L slots" and then we push them so the bolts are seated in the L and then tighten them down with Gearwrenches.

Re: Bumper easy attachment?
 

We use a C piece of aluminum that hugs the frame and there is a quick release pin on it. Makes bumper swaps very easy

Re: Bumper easy attachment?
 

Last year we made it so the corner pieces of the extruded aluminum frame were vertical with stops on the bottom. We attached those lovely teflon sliders to the back of the bumpers and threaded some 1/2" bolds on top to keep them. We could change a full set of bumpers with one drill in under a minute.

Re: Bumper easy attachment?
 

Hey guys, we are a first year team, and we dont really have that much money to spend on velcros and other stuff to only need to attach the colored cloth.

Just to double check, we only need to remove the color covering in less than 5 minutes, right, so if we have the bumper assembly separate from the covers, they could be separate right? if so, what would you suggest we do, should we make two different bumpers and have to take them out, or should we try and have a way to remove only the cloth.

If you have any ideas on this, please share, because we have alredy spend an entire day discussing this, and we are still undecided Thx

Re: Bumper easy attachment?
 

We've used these before. Cut a slot in the mounts rather than drill a 1/4" hole, and they slide right on and tighten right up.

http://www.rockler.com/product.cfm?p...2&site=ROCKLER

Re: Bumper easy attachment?
 

If you use a welded aluminum/steel chaise you can use C-Chanel that is attached to to the bumpers then drill holes in the chaise and use quick release pins.