I was checking up on bumper rules, and I had a question about R19 and figure 4-3. Specifically, over Robot Frame Perimeter C, pic attached below.
I was wondering why specifically the bottom right hand side is not legal. There are two “not ok” arrows in that corner, one pointed towards the bottom of the robot and one pointed towards the right side of the robot. It seems to me, based on my interpretation of the bumper rules, that the bumper on the right side should be fine, since the side is fully covered, satisfying the “If a side is shorter than 8 in., the entire side must be protected by BUMPER” rule.
The side there is much greater than 8" there. The side extends from the bottom right corner to the top right corner, even if there is no frame there. The backing from the robot’s frame there does not extend out 8", but the side for the purposes of frame perimeter does. Therefore, that bumper is not legal because it doesn’t extend out 8" past the corner.
And this single rule–or the misunderstanding of it–is going to cause a LOT of pain this year. This guy understands it. Many teams haven’t experienced the bumper rules and definition of a side of the Frame Perimeter.
Translation: You aren’t the only one who was wondering that…
I caught up with a local team on Monday and looked at their bagged robot. Their front bumper mount was only 2", and the back perimeter was completely open except for the wheels, which stuck out an inch past the frame. Their bumpers were also only 4" tall, so they’ve got a busy Thursday coming up when they go to competition. Sigh. Lose a year of bumper making and everyone’s a rookie again.
I saw this suggested in another bumper thread somewhere, but I think it’s worth repeating: an easy way to clarify this would be to rename “FRAME PERIMETER” to something more descriptive of what it actually is, like “CONVEX PERIMETER.” That would help alleviate a lot of confusion regarding what constitutes a side of that perimeter.
Thank you guys so much for this thread. We’ve always had normal, rectangular framed robots, so this is the first year we’ve ever needed to really understand the bumper rules. Aaaaand because of how we will have to change the bumpers, we’re gonna have to redesign our intake and take the new one in to Competition. Oh well, least we’re figuring this out now and not Thursday of the Regional.
R:19 ROBOTS are required to use BUMPERS to protect all outside corners of the FRAME PERIMETER.
For adequate protection, at least 8 in. of BUMPER must be placed on each side of each outside corner (see Figure 4-3). If a side is shorter than 8 in., the entire side must be protected by BUMPER
R:19 answers the question in this thread, Why is this picture wrong. It also explains away the misconception “bumpers always have to be at least 8 inches.”
The pictures is wrong because the corner isn’t covered on BOTH SIDES. Plain and simple. The other bumper is flagged because it covers an interior corner, not an exterior corner and is “Not a bumper”
Do your bumpers extend at least 8 inches from each outside corner? Do they fully cover any side less than 8 inches? If the answers to these questions is yes, you don’t have to worry about R19
As long as teams understand what constitutes a “side”. R19 is defined in terms of outside corners but teams seem to struggle with this and focus on the “if a side is shorter than 8 inches…” part of the rule.
The biggest issue seems to be that a through the frame perimeter intake system on a robot does not create two short sides. It creates a design problem, in that you still have one long side (with a gap in it) and need to have 8" of bumper, extending inward from the outside corners, with the result that your side had better be 16" plus the width of your intake. Which is why over the bumper intakes are popular.
I do think that the pictures in Figure 4-3 do a good job of capturing this.
