pic: 4087 Climber Addition



We had to finish our climber within our withholding allowance due to some hiccups fine tuning other mechanisms. A loose pile braided polyethylene rope (available at any hardware store) seems to readily grab the drum. If you don’t have a climber yet, you can do it before you compete! It’s the definition of low hanging fruit.

Big thanks to JamesCH95 for his ninja ghost tensioner! Happy to report it works well 3D printed with a nylon filament.

Let me know what you think!

Can I have a link to that tensioner model? We might need it.

Great addition! We are doing something very similar. I suggest that you add something to each end that keeps your rope in place and can serve to actuate the touchpad (if you don’t have something elsewhere). Here is a crude model of our current spool.

http://imgur.com/a/ZBSwG

http://imgur.com/a/ZBSwG

We are using 1.25" diameter 6061 aluminum tube with 0.125 wall thickness and 3 inch endcaps made of 0.25 inch thick 6061 plate.

PS

We didn’t think that our 0.5+ inch rope would get stuck in the 0.0625 gap between our spool and our frame at Arkansas; we were wrong.

Look forward to seeing you at Bayou!

Yep, we quickly realized the necessity of adding some flanges to each end during our testing. Here’s what we came up with: https://imgur.com/gallery/OSZC8

I’m excited to see you guys as well!

Looks pretty similar to our original design. I guess great minds think alike :). Also, do you have any kind of ratchet or similar mechanism to prevent backdriving? If not, I would highly advise a ratcheting wrench on one end of the shaft.

There’s space to install a ratcheting box end wrench on the far side of the assembly, but we have not installed it yet. I’m interested to see if it will be necessary considering our reduction/robot weight.

Clint, you hit the nail on the head with this one. We tested our new 2-piece flanges today, and found that the rope will find any gap it can to bind up in. The flange geometry didn’t seem to be too important, but under load, the rope finds the seams between the flanges every time. I’ve revised our flanges (previously pictured in an imgur link above) to be a single piece, which will hopefully eliminate that issue.

Additionally, we decided to not install a ratchet to this design, as brake mode on a speed controller combined with our reduction barely back drove under my body weight.