816 Roller Claw Test Video.

Historically, acquiring and effectively manipulating gamepieces has been 816’s biggest weakness. This year with some help from Chris Picone and one of our new Sponsors “The Inventor’s Shop” we’ve built a halfway decent claw.


The Orange Belting is 1/8" Polycord, and the black rubber material is similar to the wrap found on tennis rackets. Some of the struggling you see in the video was because of the awkward holding angle of the Drill Roller Claw combo. For the competition version we’re planning on running a RS540/550 series motor through a Banebots 36mm planetary.

(P.S. the reason the camera guy tells someone they’re not allowed to be in the video is because 816’s High School does not allow students to be in any youtube videos. I believe the penalty for breaking this rule is relatively severe.)

Looks good, my team is doing something very similar.
Is the claw going on an arm or elevator?

I heard that Chris Picone guy is pretty sweet, and that people should express appreciation by giving Team 2791 a hearty donation.

Awesome claw. You beat us to building it, so it’s good to know our numbers on compression and width appear to be rock solid.

looks good, i see that it is hard to get the square it will be easier if you try to grab it from an angle, what are your planning to use a arm or an elevator?

I think we changed your width numbers just a bit to allow for a little bit more play from left to right but your compression number seems to be spot on. From the little bit I played with knocking tubes out (not shown in the vid) they’re held really well.

The claw is designed to be used when horizontal with the ground and approximately .5-.75" off of the ground. The issues you see me having with pickup were because I was struggling to hold both the drill and the claw in the correct orientation so the bottom roller would hit the ground and kick the claw back.

How has this been working out for you? Have you had any problems with the polycord jumping?

At all or just while on school property?

The Rubber Wrap Seems to grab the tubes extremely well. We originally tested wedge-top conveyor belting, but noticed that it had the tendency to lock up the claw if it touched the carpet.

As far as the poly cord goes, it hasn’t jumped yet, and I don’t believe it will under normal operation. The rollers have a 1/8" Deep Groove machined into them to hold the poly cord so it takes a substantial amount of effort to get the belts to jump. I did notice some issues with the belts we used for reversing the top and bottom rollers though. It seems that when the tubes contact the cross in the belt it can bind up the mechanism. It should be relatively easy to fix that though, we’ll probably add a piece of aluminum round bar or something similar as a Mechanical stop and also add a limit switch to prevent the operator from over driving the claw, as well as giving much needed feedback during both autonomous and teleoperated modes.

While on school property, and while attending school events that are off of school property. The rule was originally put in place because a large number of videos were posted of questionable activities being done while on school ground.

I’m not to certain of the specific wording of this rule since it’s been two years since I’ve been a student, but I figure “better be safe than sorry”.