Bumper Backing Question

Competition Rules/Strategy
1

R26 BUMPERS must be supported by the structure/frame of the ROBOT (see Figure 4-9). To be considered supported, a minimum of ½ in. at each end of the BUMPER must be backed by the FRAME PERMIETER.(emphasis added)

Question: What is considered “backed”?

Scenario:

  1. Chassis height is 2-4.5" off the ground.
  2. Chassis is a full Rectangle, not U shaped.
  3. At least 8" of Bumper is mounted at each corner of the Chassis with the bottom at the 4" level per rule R22 Bumper Zone (4-12"). So, the entire bottom 1/2 inch of the Bumper is backed by the Chassis.
  4. At the end of each Bumper, the Bumper is only supported by the Chassis
  5. There is no portion of the Bumper that is more than 1/4" away from the Chassis. There is no gap at each end of the Bumper.

Question: Does the proposed Bumper satisfy the rules?

Seems like it meets the literal definition of R26. R26 does not state a minimum height that the Bumper must be in contact with the Frame Perimeter in order to be considered “backed”.

Note: There are occasional pillars that further support the Bumpers to keep them from rotating if it is hit higher than the chassis line. The Chassis will keep the Bumpers from moving in the Yaw Axis, and the pillars will keep the Bumpers from moving in the Pitch Axis.

In prior years, we used the Andymark Kit Chassis, and that had 1.5" contact with the Bumper. We never thought about how little contact we needed to have in order to meet the rule. Due to placement of other items on the Chassis Frame, it would be difficult to have Pillars at each Corner, and at the 8" end for the 8" Bumper segments.

2

We have a similar situation with our bot. As far as we can tell it is legal. However what happens when someone with taller bumpers hit the top portion of your bumpers. Are they strong enough that the will not bend in?

3

There is no defined minimum amount of contact with the frame to satisfy the “backed” rule. Inspectors are really looking for something that can withstand rigorous gameplay, and this includes robots with bumpers at a different height hitting you, and hitting you hard.it’s in your best interest to make sure your bumper can withstand that interaction… if your plywood breaks, or your mounting system snaps, then you’re sidelined until you can get it fixed. And that may require a trip to the hardware store for more plywood!

For what it’s worth, the old c-channel frame usually only had 1" of material backing the bumpers.

This year my team has the bottom 1 1/2" backed, with vertical supports extending another 1 1/2" every 6" or so.

4

Rich,
The supported/backed by frame and the gap rules are simply to prevent bumper failure. Larger gaps and no support lead to bumper failure as Jon stated above. As inspectors we want you to play in as many matches as you want. If your bumper system fails, other damage to the robot is likely. We want you to play.