Bumper Attachment

How do we comply to the “blind” fastener requirement? We know we need to be able to take the bumper on and off, but we don’t know how to do that.
We’re trying to attach it to the KitBot rail but we can’t unbolt it easily.

I’m a female freshman on this team and very new to basically all this stuff, but I am trying to put all my effort with this part of the robot (I volunteered to be in charge of the bumpers) and finishing it ASAP.

Thank you for any replies.

~CHIBO: The BluePhoenix

You could try using a carriage bolt. These bolts are designed for “blind mounting”. In other words you drill a hole in the plywood and slide the bolt through before you put the pool noodles and fabric on. As you tighten the bolt from the back of the plywood it will pull the bolt in tight to the wood and there is a square shape on the shaft of the bolt close to the (rounded) head that will keep it from turning.

Alternatively you could try counterboring for a hex-head bolt and holding it in place with epoxy… but the carriage bolt is probably your best bet.


Who says you even need bumpers?

No one said it was ‘needed’.
But it is recommended, so my team decided to take the recommendation. XP

It sounds like a good idea, but our robot doesn’t have enough space in order to do that (or work in our favor. This is because that space is being occupied by the wheels.)

The suggested item is a T-nut, it looks like a T has a threaded center and some have small spikes that stick into the wood. You drill a hole in the 3/4" plywood and put them in before you cover the pool noodles. You are going to need a place on your frame to attach which if your bumper is to spec is 5" from the floor (2.5" space and half way up the 5" bumper). This method would leave you putting a bolts through the frame and into the T nuts. Hope this helps.

I was wondering, Does a “quick installation and removal” mean that we can attach a bumper by screwing a bolt into the wood, or does it have to be held in by gravity and/or a clamp? In other words, would they allow us to come up with a screwdriver and take the time to come up from the back of the chaise and unscrew some bolts to remove the bumpers?

Also, can I put a hole in the 1000 denier Cordura Plus cloth? it seems the cloth is strong enough.

If the answer to both is “Yes,” Then I have a solution. A wood block with a hole through it set inside the chaise with a T-nut would be another solution. Then, you tighten the bolt from through the cloth. That would solve the “lack of space by the wheels” problem

Just a possible solution

“Quick installation and removal” means that you can take it off and on in time to weigh in. I would think that bolts would be just fine, provided that you could access them alright.

We’re using aluminum extrusion this year - simply put a long T nut on each side of each bumper, and slide them right on! Easy, and they look great.

just one big question: what part(s) of the bumper mountings have to be part of the robot weight?

The part that doesn’t come off the robot, the part that is permanently affixed.

Note that bumper construction is pretty well defined, you can’t have a lot of extra doo-dads on it. The bumper is the plywood, noodles, cover material, fasteners to hold the whole mess together, and the bolts that go through the wood to connect it to the robot. Nothing more, nothing less.

The only thing not addressed is the nuts that will be tightened on the bolts - I presume you can count those as bumper weight. (Because they’re not a fixed part of the robot.)

we’re having trouble finding Cordura at a store, and we’re afraid it’s a little bit late to get it shipped, even overnight shipping…any ideas as to where we could get some?

no ideas on how to procure some but this is one thing my team is doing, we are taking the measurements for the bumpers now and finishing them later(aka after ship date).

We finally got ours at an upholstery shop and in another thread I pretty much vented at the lack of availability of this specific fabric and the non-disclosure of alternates.

Anyways, try an automotive upholstery shop.

Good luck!!!