Need help with bumpers

[EricH]

What sort of problems? Nuts falling out, bolts not long enough, accesibility?

[synth3tk]

Try a strip of metal, covered with 1/2 inch foam, and wrapped in duct tape. Bolted it onto the frame, voila. Took all of 5 minutes during the final build day. I don't recommend it, but we waited too late.

[EricH]

Originally Posted by blakcheez

Try a strip of metal, covered with 1/2 inch foam, and wrapped in duct tape. Bolted it onto the frame, voila. Took all of 5 minutes during the final build day. I don't recommend it, but we waited too late.

Not a spec bumper, unless the 1/2 inch foam was pool noodles. I think he's asking about spec bumpers.

[synth3tk]

Originally Posted by EricH

Not a spec bumper, unless the 1/2 inch foam was pool noodles. I think he's asking about spec bumpers.

Ah, ok. Anyway, do you have any good generic designs? I'm trying to make sure we have a much better bot than last season. Craig, I like that design a lot.

[EricH]

Originally Posted by blakcheez

Ah, ok. Anyway, do you have any good generic designs? I'm trying to make sure we have a much better bot than last season.

Bolt and blindnut (or ordinary nut, depending which way you want to go) through a hole in the frame. Use on spec bumpers.

Accessibility has always been an issue for us. This season, we're going to have a new setup. Imagine the meshing section of a hinge, but all square. Put several of these along the bumper, so bolts can drop in from the top. If this isn't that clear, I'll throw a CAD up in a few minutes...

Edit: Image 1 shows the two separate.The bottom section of the plate is threaded. When put together (image 2) the bolt can be dropped into the hole, and threaded in. This should allow us to change out from red to blue bumpers quite easily based on which alliance we're on.

[AndyB]

Originally Posted by 114ManualLabor

Accessibility has always been an issue for us. This season, we're going to have a new setup. Imagine the meshing section of a hinge, but all square. Put several of these along the bumper, so bolts can drop in from the top. If this isn't that clear, I'll throw a CAD up in a few minutes...

Edit: Image 1 shows the two separate.The bottom section of the plate is threaded. When put together (image 2) the bolt can be dropped into the hole, and threaded in. This should allow us to change out from red to blue bumpers quite easily based on which alliance we're on.

Would that be considered spec? Or do bumper fasteners count towards weight.

Originally Posted by AndyB

Would that be considered spec? Or do bumper fasteners count towards weight.

The bumper mounts on the frame side would be counted in the robot weight. But the piece on the bumper side, as long as it's under 15 pounds for the whole setup, is fine.

[AndyB]

Originally Posted by 114ManualLabor

The bumper mounts on the frame side would be counted in the robot weight. But the piece on the bumper side, as long as it's under 15 pounds for the whole setup, is fine.

Gotchya. Thanks.

[IndySam]

Originally Posted by 114ManualLabor

The bumper mounts on the frame side would be counted in the robot weight. But the piece on the bumper side, as long as it's under 15 pounds for the whole setup, is fine.

We had a similar setup on our 2006 bot. Pull 4 pins and they popped right off. It worked very well. We did have to remove the brackets from the bumpers and weigh them with the robot, also the pins.

Last year the bumpers were all hinged together. We had brackets along the back that simply went over the frame. The brackets in front were held on by pins. Remove two pins and the whole thing came off. Just like 2006 we also had to remove the brackets and weigh them with the robot.

[=Martin=Taylor=]

We had tiny flanges on our bumpers last year that locked into our 80/20 frame rails. Each bumper was attached with only ONE bolt. Never had a problem taking them on or off.

A crude picture is attached. You can see the three flanges on the left bumper.

[Gdeaver]

One thought on bumpers and thier mounting. The plywood and aluminum frame can be a stuctural part of the robot. The mounting can be very critical if a team wants to integrat the bumps into the frame as a structural member.

[Jeff K.]

We used blocks of abs that were mounted to the back of the plywood with some machine screws. They fit into 2x1 aluminum tubing we welded onto the side of the chassis and then we drilled a hole vertically through it all and held it in with a clevis pin and a hairpin cotter pin. For the front and back, we drilled 2 holes that the pins went through, so the pin took the place of the bolt. Looked cleaner and was easier to remove for doing maintenance and inspection. Didn't have any problems and it held it nice and snug.

[Mike Martus]

Caution!

Bumpers have specific materials, specifications and mounting rules.
It is very important to read the section of the manual that covers this.
Violations will not pass inspection.

Hey... there may be changes for 2008, who knows?

[EricH]

Originally Posted by Mike Martus

Caution!

Bumpers have specific materials, specifications and mounting rules.
It is very important to read the section of the manual that covers this.
Violations will not pass inspection.

Hey... there may be changes for 2008, who knows?

Unless you make custom bumpers, in which case you need to have them fit in the box and 120 pounds (or whatever it is) weight limit and you may as well make them an integral part of the robot. You still need to make sure to have them qualify as bumpers, though.