[dtengineering]

I'm going to be inspecting in Seattle and Calgary over the next two weeks, and have been following the bumper discussions with interest. While final decisions, of course, will rest with the lead inspector, the idea of intentionally building heavier mounts to add weight/shift CoG, is an interesting one.

When I think of the bumper mounts that we built for our robots, we would often use 1/8"x1" steel band iron bolted to the noodle side of the plywood. We'd drill and tap the band iron and run bolts through the plywood and into the band iron, essentially using the tapped band iron as a fixed nut.

Well, would be have been wrong to use 1/4" x 1 1/2" steel? Would we have been wrong to use longer pieces of steel? Would we have been wrong to use 1/2" bolts instead of 1/4" bolts? Would we have been wrong to use four mount bolts at each mount point instead of two? Would we have been wrong to have four mounting points on our bumper instead of three? We probably would have been wrong to use depleted Uranium instead of steel, and using Gold would have put us over the $400 per part... but we could have used Brass to increase the density of the mount.

So we could have easily increased the weight of our mounts by a factor of 8 and still clearly been within the rules, so long as the overall weight was less than 20 pounds.

At some point the mounts might become so large as to reduce the protective nature of the bumpers... for instance if they begin to infringe upon the cross section of the pool noodles... or so long as to effectively violate the diagram (4-4, I believe) showing the cross-section of the bumpers. I think it would be reasonable for an inspector to insist that at some point along the length of the bumper (perhaps even along the majority of the length) the cross-section of the bumpers should match the diagram.

But bumpers that meet the rules meet the rules... even if they intentionally have heavier mounts than are structurally needed.. are legal.

Jason