233 telescoping arms how do they work?

[George C]

Originally Posted by fr05ty27355

What did 254 and 233 do to pin the chain/belt to a stage? I'm wondering if they put bolts through the chain/belt, pinched the chain/belt against a toothed surface, or did something else. I'm guessing they might have had different methods since 254 used a belt and 233 used chain.

We did something similar for a two-stage cascading mechanism driven by a Gates belt. We were able to saw and file a piece of aluminum to match the Gates tooth profile. The block covered about 6 teeth and we avoided putting holes through the belt. Worked perfectly on the second try.

[Nuttyman54]

Originally Posted by George C

We did something similar for a two-stage cascading mechanism driven by a Gates belt. We were able to saw and file a piece of aluminum to match the Gates tooth profile. The block covered about 6 teeth and we avoided putting holes through the belt. Worked perfectly on the second try.

971 did a similar attachment method with a machined block to match the belt tooth profile for their elevator in 2011.

For #25 chain, you can fit #4 screws through the gaps between the rollers to fix it to something, although I don't know if this is how 233 does it or not. Another method is to drill a hole in the fixed structure that one end of a masterlink fits through.

[thefro526]

Originally Posted by Nuttyman54

For #25 chain, you can fit #4 screws through the gaps between the rollers to fix it to something, although I don't know if this is how 233 does it or not. Another method is to drill a hole in the fixed structure that one end of a masterlink fits through.

I've also used #4 Screws to fix #25 chain before, it works just fine when done right but can be a bit tricky considering the size of both the chain and the screws.

233, in 2011 at least, machines a part that appears to 'look' like a #25 chain link at either end and uses that to fix the chain to the stages. Here's a few pictures on their flickr.

http://www.flickr.com/photos/thepinkteam/5787028180/

http://www.flickr.com/photos/thepinkteam/5787033770/

http://www.flickr.com/photos/thepink...n/photostream/

[BurkeHalderman]

Has anyone tried using these to attach chain? Specifically the K-1 style connector.

http://www.mcmaster.com/#roller-chai...hments/=p1acmb

Seems like an easier option than machining an attachment for the chain.

[Nuttyman54]

Originally Posted by BurkeHalderman

Has anyone tried using these to attach chain? Specifically the K-1 style connector.

http://www.mcmaster.com/#roller-chai...hments/=p1acmb

Seems like an easier option than machining an attachment for the chain.

I'm sure it's been done, but #35 chain is the smallest size that you can get those style links in. Most of these style elevators have space and weight at a premium, so #25 chain is preferred.

[yash101]

Maybe fill it up with pressurized air (like a piston out) to make it longer, and have a spring retract it. Maybe that will work for light/medium loads

[Jared]

Originally Posted by yash101

Maybe fill it up with pressurized air (like a piston out) to make it longer, and have a spring retract it. Maybe that will work for light/medium loads

If you could get the thing air tight (which would be really tough) I don't think it would be legal per the 2013 rules. I know a team wanted to fill a balloon with air from the compressor, but they weren't allowed to.

[EricH]

Originally Posted by yash101

Maybe fill it up with pressurized air (like a piston out) to make it longer, and have a spring retract it. Maybe that will work for light/medium loads

Except that if you don't do that with a COTS pneumatic cylinder, you're in violation of the rules (specifically R76). I don't see the ban on non-COTS pneumatic items going away anytime within the next decade, if not century. On top of the large volume of air you'd need for any reasonable extension length, and the fun of fitting at least one cylinder that long inside the arm, which make for a very nasty engineering challenge between them...

[Brandon_L]

Am I the only one that likes the lead screw method?

Its beautiful.

If you ask, they're more then happy to share some drawings on that arm. I have them saved somewhere. To me, it seems a little more simple and solid then all these chain runs. Cons being I'm not sure how you'd have multiple stages.

[DampRobot]

Originally Posted by Brandon_L

Am I the only one that likes the lead screw method?

Its beautiful.

If you ask, they're more then happy to share some drawings on that arm. I have them saved somewhere. To me, it seems a little more simple and solid then all these chain runs. Cons being I'm not sure how you'd have multiple stages.

Very cool! I love the robot, I'm really surprised not to have heard of it before.

I suppose another disadvantage of the leadscrew would be it's expense and inefficiency. Of course, it does look like a very elegant solution in that situation.

[Jared]

Originally Posted by Brandon_L

Am I the only one that likes the lead screw method?

Its beautiful.

If you ask, they're more then happy to share some drawings on that arm. I have them saved somewhere. To me, it seems a little more simple and solid then all these chain runs. Cons being I'm not sure how you'd have multiple stages.

If you use lead screws right, they are a really solid and durable solution, but may be overkill for some applications. This year, our climber used two lead screws, and although it was heavy, we never had a single mechanical problem with the lead screws, which was the only part of any robot we've ever built that was this reliable. We fell off of the top of the pyramid, and from the second level, and our climbing device wasn't damaged at all.

[MichaelBick]

Stuff got moved around in my google drive, and the previous album link now does not work. I got a PM to repost the link so here it is: https://drive.google.com/folderview?...&usp=sha ring

I will have to try to find a more permanent solution for the future.