our team has run into a little snag w/ our bumper design, all of the dimensions are set and the mounts are on the robot, but there is a shaft thats going to be sticking out of the robot just the slightest bit, but enough to be in the way of the bumpers, we were wondering if it was legal to cut a hole (2 1/4" diameter), becuase other wise were in trouble
The rules laid out for standard bumpers are being enforced very strictly. Cutting holes in the plywood is not allowed. One option worth considering is creating two sections of bumper that go on either side of your protrusion.
are you absolutely sure, because there is nothing in the manual saying against it, im pretty sure you know what your talking about but i want to make absolutely sure because otherwise i have alot more work ahead of me
You can check with the official FRC GDC Q&A, but to this point everybody that’s posed a similar problem has been met with the same answer: standard bumpers are standardized and standards have no exceptions. No altering the bumper design. Period. .
.
Yep, you must have 3/4 of your robot filled with a “Standard Bumper”. There can be no modifications to the bumpers or they would not be “Standard” bumpers.
Just split up the bumper into two parts on that side and you will be fine
Should be 2/3
This may be a silly question. If the shaft is just sticking out just the slightest bit, why not just cut off the end of the shaft? If it is just sticking out, it must not be doing anything where it sticks out anyway.
its not so much that the shaft is sticking out, the pillow blocks its in stick out of the frame of the robot about a quarter inch. thats whats getting in the way of the bumpers
Is it still within the size requirements with that block sticking out? If it is, you could make standoffs to set the bumper away from the robot enough so it won’t interfere with the block.
the bumpers are already 3 1/2 inches out of the robot, i wish i had some extra room. i really dont want to have to divide the bumpers (one on the two sides of the robot), because weve already welded the mounts and “prettified” the frame, so were not doing anymore welding
Well it looks like you have quite a few options here.
-
Ask the Q&A to verify the comments that have been posted here, all previous bumper questions have outlawed any modifications to the standard bumper system as described in the manual and I don’t think this would be any different, but you can definitely try.
-
Change the design of the protruding shaft/pillow block setup so it does not protrude from the frame.
-
If you still fit in the 28"x38" box with the protruding pillow block (which you must do anyway), then you can use standoffs as suggested by usbcd36 to mount the bumpers outside the protrusion. If your bumpers are more than 3.5" thick I would examine whether or not they were designed according to official specs as a 2.5" diameter pool noodle and a 1/4" sheet of plywood do not add up to near 3.5". Mounts for the bumpers that are attached to the robot do not count towards this 3.5" and must fit within the starting dimensions of 28"x38".
-
Suck it up and split the bumper.
Regardless of which option you choose to go with, hopefully your team uses this as a learning experience. All parts of the robot design must be considered from the very beginning. This goes for big things (size, weight etc.) as well as small (flag holder, bumpers, RC visibility).
We had something similar last year. We ended up with shaft collars on the outside of our pillow blocks to help with end play. We just mounted the bumpers over the collars/pillowblocks and everything worked fine. Ours did not stick as far as yours do. Our frame started out about 0.75 inches less than 28 inches so we had the room to do it. It sounds like from previous posts you may all ready be beyond the length/width requirements, I hope not. If you are not, the 3 1/2 inches would start at the end of your shaft. A couple of washers/spaces to give support bewteen the bumper and frame and you should be good to go.
And I have just posted a very similar question to the Q&A system (only to find out seconds later that it had already been answered in a different subforum), for which I apologize to the GDC. I wish I could delete that question to alleviate the GDC on answering the same things over and over… :rolleyes:
My bad! 
You’ll be fine boring material out of your wood. Try to put yourself in a position where you don’t have to make a through-hole in the wood. That will come off better to the inspectors.
Last year we had so many bolt heads sticking our of our chassis that we had to drill half-way through our plywood in order to allow the plywood to sit flush with the chassis metal.
Sam
According to the Q&A Dave just linked to, you will not be fine boring material out of your wood.
Please, please read the Q&A Dave cited! You can’t take material out of the bumpers.