Bumper rules clarification

[charles.miller]

We have waited until the last two days to create our bumpers... in years past, there has been a rules stating that the connections between the bumpers and the robot frame must be, at most, eight inches apart. This year, however, we could not find such a rule. We are wondering if anyone has an answer to our problem. Thanks!!!!!

[SenorZ]

As long as there is no more than a 1/4" gap between the frame and the bumper backing, you may have more than 8" of "unsupported" bumper.
...unless I've totally misread the following rule and associated Figure.

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 PERIMETER. Additionally, any gap between the backing material and the frame:
A. must not be greater than ¼” deep, or
B. not more than 8 in. wide

[serenagh]

Clarifying question on "backed by" - must all (5") of bumper plywood be touching metal structural elements? Would a 1" rim be enough? In the diagrams, it doesn't seem like there are continuous metal pieces on the frame, and the frame perimeter is also defined by an upward projection).

[GeeTwo]

Originally Posted by serenagh

Would a 1" rim be enough?

Per the rules, I don't see any reason it wouldn't. However, given the intended function of the bumpers, (provide protection in collisions) I would recommend significantly more backing. For example our bumpers this year only have about 1" of overlap with the KoP chassis, but we added some 4" steel angle brackets on the front and rear and some aluminum side plates that reach above the bumpers on the left and right.

[ToddF]

Originally Posted by serenagh

Clarifying question on "backed by" - must all (5") of bumper plywood be touching metal structural elements? Would a 1" rim be enough? In the diagrams, it doesn't seem like there are continuous metal pieces on the frame, and the frame perimeter is also defined by an upward projection).

Based on our "passed inspection" robot the answers to your questions are NO and YES. Don't skimp on your bumper fabrication. In this game they take a beating.



More pics.

[FrankJ]

Originally Posted by serenagh

Clarifying question on "backed by" - must all (5") of bumper plywood be touching metal structural elements? Would a 1" rim be enough? In the diagrams, it doesn't seem like there are continuous metal pieces on the frame, and the frame perimeter is also defined by an upward projection).

There is no specified minimum. So theoretically it could be a knife edge. But it needs to be "robust" which is a judgment call. We routinely use 1" box channel for our frame perimeter. That has never been questioned.

There is also a 1/2" minimum on the corners. Once again that is linear and an area.

As others have said: It to your advantage to make sure your bumpers are roboust.

[rich2202]

There is no rule this year that mandates attachment points. The rule is what is behind the bumper.

In theory, you could have pillars every 8 inches to "back" the bumper, and have only one attachment point. It wouldn't be very robust, but that is the team's choice.

[jvriezen]

Originally Posted by rich2202

There is no rule this year that mandates attachment points. The rule is what is behind the bumper.

In theory, you could have pillars every 8 inches to "back" the bumper, and have only one attachment point. It wouldn't be very robust, but that is the team's choice.

I think that theory would break the rules:

R21g: 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,
tape, or tie-wraps). The attachment system must be designed to withstand vigorous game
play. ...

So not really a choice.