Our team is currently working with a local sheet metal company to get ready for the 2014 season. We have been working on various designs and are wondering how teams mount bumpers.
In the above pictures, are bumpers mounted in the indented panels? How exactly could we mount bumpers?
-Graham
Generally speaking, you could fashion a mount to attach to the top areas pretty easily. You could also bend up some mounts to go into the pockets and put bumper mount points there, similar to a WCD’s bumper mounts. Or you could reverse the panels that create the indents. Or… You could get creative and come up with something completely out of the box.
Those look familiar… 
The inverted outer C rails were used in 2009 to recess the live axle bearings, so they could not be exposed directly to the bumper frame. Small wood or plastic blocks were added to provide additional backing behind the bumper (you cannot mount bumpers into the indented portion of the frame unless that frame is removed with the bumpers).
At the time this was the easy way out, but after putting more thought into it in 2011 we were able to swap the C rail back to facing inwards. The bearing protrusion issue was solved by adding a 1/8" sheet metal shim to the inside of the center wheel and having the outer wheels inside a separate bracket inside the knocked off corners.
The bumpers we used on those frame styles generally had 1/2" aluminum posts mounted onto the frame, then sheet metal brackets added to the bumpers. They would be added and taken off vertically, with hairpin cotter pins (R-clips) used to keep them in place. The 2011 frame had segmented bumpers that were added and removed horizontally, although I believe in 2012 and 2013 they returned to bumpers that were added and removed vertically (over the top of the robot).
Thanks for the direct relation (I presume you were the CADer )
So take the 2009 frame for instance, if we did something similar with the c rail facing outwards, but created a bracket that connected the top and bottom rails and then latched to the bumpers.
Something like this? (ignore the pitifulness of the AutoCAD mockup haha)
After looking back through photos, here’s a photo of the blocks used to fill this void on the 2007 robot. http://team228.org/media/pictures/view/3000
I just came across these when researching the same problem on our prototype. Seems like the perfect solution:
On second read, I should be a bit more clear - if secure the bumpers to the top flange of the outer rails (using the panel nuts), rather than inwards to the webs, you should need any spacers (you might need to make the bumpers one or two pieces though, and have them wrap around the front and back rails.
We used those (or something very similar) last year and they were terrific. It made for probably the fastest bumper change we’ve had.
We used twist latches this year and so did 1477. They aren’t perfect but they are very quick to change. If we use them again next year we will use more than 4 and probably use the larger ones like 1477 did. We had them come off a few times.
If you don’t mind your bumpers coming off a little more slowly, you can effectively use them as a structural member.
In 2013 33 ran a single piece bumper system with the mounting hardware being a 2x1 welded box beam going all the way around the robot mounting to the underside of an outward facing flange.
This is what it looked like.
Just another option to consider.
Cheers, Bryan
Last year my team used something similar to this. We attached a right angle bracket to our bumpers, and then use the the slide latch to attach the bracket to the top flange of our frame.