Is this a legal bumper config?

[ksafin]

Had a quick question with our bumpers..

We're having a WCD this year and found that it was too low to the ground to mount bumpers. We could space up the bumper and attach it to the drivetrain frame but were wondering if the following was legal:

We have a mezzanine attached to the top of the drivetrain frame as a support structure to mount all of our stuff.. would it be legal to mount our bumpers to this mezzanine?

That is to say, is it OK to mount the bumpers to some upper support structure rather than the drivetrain frame? Is the "FRAME PERIMETER" the drivetrain perimeter or can it be the perimeter of the mezzanine? (which are the same)

Here's a picture to show what I mean.
You can see a side view of the WCD, with two channels at each end that are vertical and a horizontal bar (this is the mezzanine). The blue represents a bumper mounted to the mezzanine channel.

[jblay]

As long as the bumper is below 10 inches and above 2 inches you should be fine. Your bumper doesn't have to mount off of your drive base.

[ksafin]

Originally Posted by jblay

As long as the bumper is below 10 inches and above 2 inches you should be fine. Your bumper doesn't have to mount off of your drive base.

Awesome, just wanted to make sure. Thanks.

[BBray_T1296]

If the bumpers are true-to-drawing, The would be illegal as the corners in front/back are not protected. Like jblay said, as long as they are entirely within 2-10" of height, it does not matter what they are mounted to, provided that the mount is sturdy enough to take the impact of robots.

If you are planning high bumpers, I would personally advise against doing so if at all possible. This is due to the phenomenon where in a pushing match, the robot with the high bumpers tends to ride up on top of the bumpers of the low bumper robot, transferring a small but significant amount of your weight to their wheels, giving them more traction and yourself less (f=uN)

[jblay]

You have to make sure that your corners are covered yes. It can be the lower or upper bumper that covers the corner, but one of them has to.

[GaryVoshol]

Your Frame Perimeter is defined by the outermost points of your Robot, located between 2 and 10 inches off the ground. If your "mezzanine" is the outermost part of your Robot, and it's located no more than 10" off the floor, it defines your Frame Perimeter and that's where your Bumpers must be attached. If another part of your Robot is wider, then that wider part is where the Bumpers must go. You could also use properly spaced stand-offs attached to your mezzanine to define your Frame Perimeter.

[tavar321]

Adding on a very similar question: Does the bumper necessarily have to cover the frame element or could it just be attached to the frame member?

For context: the bumper zone is between 2" and 10," the base of our frame is 1.5" off the ground (up to 2.5"). We were thinking of attaching bumpers to the top of the frame, but not necessarily covering the 1" frame.

See the picture below for a picture with measurements, the plywood represents where the bumper would be.

[Jon Stratis]

There's no requirement that bumpers cover your frame... however, bumpers " must attach to the FRAME PERIMETER of the ROBOT with a rigid fastening system to form a tight, robust connection to the main structure/frame (e.g. not attached with hook-and-loop or tie-wraps). The attachment system must be designed to withstand vigorous game play." It is in your best interest to ensure there is sufficient support behind the bumpers that they will not come off - mounting them with some 1" angle where the only support behind the bumper is that 1/2" worth of frame would probably not be a robust connection - one good hit near the top of the bumper and it would bend/break off.

[Bob Steele]

Just a word of warning .... legal or not...
High bumpers can cause some real issues during gameplay.
Most robots will have low bumpers...

I am sure some other teams on CD can discuss the implications of really high bumpers during game contact....

[GaryVoshol]

And don't forget the new rule this year, if your bumpers go out of compliance (e.g. become loose and sag below 2") you get disabled. Ugg.

[DonRotolo]

Also, please bear in mind the vast difference between "frame" and "FRAME PERIMETER". The latter is very specifically defined, and that's what you MUST protect with BUMPERS, not the "frame" of your robot.

[tavar321]

@DonRotolo - Does that necessarily mean completely covered though?

Currently the bumpers are planned to mount with C-Channel attachments that are then pinned to the 16th" seen in the photo. We can also (and probably will) move the bumper down 1/2". I'm inexperienced with bumpers, so I don't know if these combined supports would be enough.

@John - We're using 2 pieces of C-Chanel connected to the 16th inch by 2 aluminum pin connectors each, would this fall into the 1" angle you meant? I would assume they could take some sheer stress, though not to large.