Bumper Mount

[xxvg]

I was wondering if someone can explain the difference between being "supported" and being "backed" by the frame perimeter.

Also, if someone can specify the bumper ends being "supported at least 1/2" of the frame perimeter"
does the bumper wood end have to be attached and touching the frame perimeter or is being a 1/4 or less inch away from it okay?

[Al Skierkiewicz]

xx,
The wording speaks to similar items. The bumpers need robot frame to function. To be attached to the frame, the bumpers need to be supported by the frame. To be effective, the bumpers need to be backed by robot frame with little to no gaps between the bumper and the frame or from one point of structure to another. The 1/2" dimension is to insure that the ends of the bumper have some robot frame to absorb some of the shock that occurs with robot collisions. The object of all the bumper rules is to prevent failure of the robot system and to protect the robot from irreversible damage that might occur in a collision.

[Thad House]

We have a similar situation. We have are frame perimeter, and its solid. But we have some bolt heads sticking out. When we place the bumpers on the robot touching the bolt heads, the end of the bumper is not actually touching any metal. there is about .2 of a gap between the wood and the frame, and this is because of the bolts. In R26, it says the bumper must be backed by the frame perimeter at the ends. How do bolts outside the frame perimeter affect this? If we space the bumpers out, does the ends having a 1/4 inch gap between the wood and the frame affect the rule? Because if so, it seems like most kit bots would fail too, because I know there are bolts sticking out on the kitbot.

[xxvg]

Have you guys competed yet? Was it legal? Did it pass inspection?

[MetalJacket]

Originally Posted by sst.thad

We have a similar situation. We have are frame perimeter, and its solid. But we have some bolt heads sticking out. When we place the bumpers on the robot touching the bolt heads, the end of the bumper is not actually touching any metal. there is about .2 of a gap between the wood and the frame, and this is because of the bolts. In R26, it says the bumper must be backed by the frame perimeter at the ends. How do bolts outside the frame perimeter affect this? If we space the bumpers out, does the ends having a 1/4 inch gap between the wood and the frame affect the rule? Because if so, it seems like most kit bots would fail too, because I know there are bolts sticking out on the kitbot.

If you guys have access to a router or even a drill depending on how your bumpers mount, you can make small pockets in the bumper to allow the wood to sit flat on your frame. See R21.A
[quote]
A. be backed by ¾ in. (nominal) thick by 5 in. (± ½ in) tall plywood or solid, robust wood. Small clearance pockets and/or access holes in the plywood backing are permitted, as long as they do not significantly affect the structural integrity of the BUMPER.
[quote]

[xxvg]

Thanks Al,
so if there is no mount connecting the bumper ends to the frame, but there is a little gap, will it be legal? The mount of the bumper to the robot is connected more towards the middle.

xx

[Al Skierkiewicz]

It is possible and legal to mount the bumpers over boltheads that do not exceed 0.250". The bumpers do not need to be fastened at the ends, but there does need to be robot structure at the ends. The KOP frame when correctly assembled, has a 5/8" flange that is folded over at the top of the side plates. This is sufficient structure to satisfy the 1/2" backing rule. Please see the pictures for a detailed view of this part.

[Thad House]

Originally Posted by Al Skierkiewicz

It is possible and legal to mount the bumpers over boltheads that do not exceed 0.250". The bumpers do not need to be fastened at the ends, but there does need to be robot structure at the ends. The KOP frame when correctly assembled, has a 5/8" flange that is folded over at the top of the side plates. This is sufficient structure to satisfy the 1/2" backing rule. Please see the pictures for a detailed view of this part.

I get that. I'm talking about on the sides, and not the front or back. We have a 1/4" gap between the frame and bumper, thats caused by the bolts spacing out the bumper from the frame. The question is does that structure at the end have to be touching the bumper, or can there be a small gap caused by the bolts outside the frame perimeter.

[xxvg]

Originally Posted by Al Skierkiewicz

It is possible and legal to mount the bumpers over boltheads that do not exceed 0.250". The bumpers do not need to be fastened at the ends, but there does need to be robot structure at the ends. The KOP frame when correctly assembled, has a 5/8" flange that is folded over at the top of the side plates. This is sufficient structure to satisfy the 1/2" backing rule. Please see the pictures for a detailed view of this part.

So having a 1/4" gap between the bumper ends and the frame is legal? pertaining to
"Bumper Ends must be supported by at least ½” of robot Frame Perimeter"
and there is no mount connecting the bumper to frame at the ends, it is just less that 1/4" because it is mounted more towards the middle.

[xxvg]

Thank you alot for all of your replies and comments! Helps alot. xxx

[FrankJ]

This years game is very rough on bumpers. Irregardless of what the rules say (not to say don't follow the rules as well) your bumpers need to be sturdily attached to your robot. You should be able to pick up & pull your robot around by the bumpers. You are allowed to make pocket holes for bolt heads. Rather or not you should do that depends on how well the bolt heads support the bumpers. It is a judgment call.

[Thad House]

Originally Posted by FrankJ

This years game is very rough on bumpers. Irregardless of what the rules say (not to say don't follow the rules as well) your bumpers need to be sturdily attached to your robot. You should be able to pick up & pull your robot around by the bumpers. You are allowed to make pocket holes for bolt heads. Rather or not you should do that depends on how well the bolt heads support the bumpers. It is a judgment call.

Yeah its gonna be rough out there. We have a whole 2x1 structure mounted to the bumpers above the chassis all the way around the robot, with lots of bolts. We solved the strength issue in other ways because I saw that it was going to be a hard hitting game, and ive seen alot of bumpers bend before.

[trcsmith]

Originally Posted by FrankJ

This years game is very rough on bumpers. Irregardless of what the rules say (not to say don't follow the rules as well) your bumpers need to be sturdily attached to your robot. You should be able to pick up & pull your robot around by the bumpers. You are allowed to make pocket holes for bolt heads. Rather or not you should do that depends on how well the bolt heads support the bumpers. It is a judgment call.

G20 ROBOTS must be in compliance with Section 4.6: BUMPER Rules throughout the MATCH.
Violation: DISABLED

Does this apply to fabric touching the carpet while in game play??

[Mr V]

Originally Posted by trcsmith

G20 ROBOTS must be in compliance with Section 4.6: BUMPER Rules throughout the MATCH.
Violation: DISABLED

Does this apply to fabric touching the carpet while in game play??

Yes a robot that has any part of their bumper outside of the bumper zone should be disabled.

[Al Skierkiewicz]

Thad,
The 1/4" gap rule applies to the bumper in the corners as well. We understand that KOP frame has hardware that stick out. Please be sure to assemble the frame so that the bearings are facing the correct way. As always, (this year more than most) bumpers require secure fastening to the robot frame. Two screws on each segment may not be sufficient. Ask your inspector for assistance if you cannot find a suitable attachment method.