Conveying along chain

[ollien]

I've been googling around about this for the past couple of hours, but I can't seem to wrap my head around how teams are utilizing chains for linear motion. Currently, the best item I can find to do something like this would be something like this, but my gut tells me that these would be rather fragile for anything more than a few pounds. If I wanted to move a load along a chain, how would I best accomplish this?

[hectorcastillo]

You can put bolts through the holes in the links to fasten whatever you want to move with the chain. I believe #4 bolts work for this.

[cad321]

We used home made versions of what you linked above on our bot last year to lift the totes. It worked alright but wasn't great. The issue we found with them is if we jammed our mechanism, it would cause of few of the attachment links to break off (they're a master link with a flange on either side basically). If you broke your chain properly (not using an insane amount of master-links) it might be feasible. Might need to do some load testing though.

What we found works really well on the other hand though is just passing bolts through the holes in the chain and bolting it to the mechanism we are moving. As long as you aren't needing to have the chain loop around the sprocket, this method is clean and easy to implement.

[ollien]

Originally Posted by hectorcastillo

You can put bolts through the holes in the links to fasten whatever you want to move with the chain. I believe #4 bolts work for this.

And that will hold? Is there a stronger alternative?

Originally Posted by cad321

We used home made versions of what you linked above on our bot last year to lift the totes. It worked alright but wasn't great. The issue we found with them is if we jammed our mechanism, it would cause of few of the attachment links to break off (they're a master link with a flange on either side basically). If you broke your chain properly (not using an insane amount of master-links) it might be feasible. Might need to do some load testing though.

What we found works really well on the other hand though is just passing bolts through the holes in the chain and bolting it to the mechanism we are moving. As long as you aren't needing to have the chain loop around the sprocket, this method is clean and easy to implement.

Sounds neat! I do wonder about the reliability of that but it sounds like it might work. Thanks!

[DonRotolo]

Aside from those McMaster parts, there are several ways to attach to a chain - some of which can be as strong as the chain itself.

Aside from the example above, how about a loop around a small sprocket, and pull using the center bore of the sprocket? The chain can be held on with a zip tie, since it's not under stress.

Can you think of other ways?

[hectorcastillo]

Originally Posted by ollien

And that will hold? Is there a stronger alternative?

We had three #4 bolts going through our chain on our climber and it successfully lifted over 120 pounds. That being said, we only ran it maybe four or five times in total on our practice bot, and we haven't gotten to see what the strain of an entire competition would do to it, but in short, yeah it works. You can also put more bolts in or have multiple chains to help distribute the load.

[ollien]

Originally Posted by DonRotolo

Aside from those McMaster parts, there are several ways to attach to a chain - some of which can be as strong as the chain itself.

Aside from the example above, how about a loop around a small sprocket, and pull using the center bore of the sprocket? The chain can be held on with a zip tie, since it's not under stress.

Can you think of other ways?

Huh, now that's an interesting idea. Thanks! We could use an L-Bracket or something to hold the sprocket to the plate. Thanks!

Originally Posted by hectorcastillo

We had three #4 bolts going through our chain on our climber and it successfully lifted over 120 pounds. That being said, we only ran it maybe four or five times in total on our practice bot, and we haven't gotten to see what the strain of an entire competition would do to it, but in short, yeah it works. You can also put more bolts in or have multiple chains to help distribute the load.

Neat. Thanks! Questions like this always remind me why I'm the programmer and not the project manager.

[Chak]

Originally Posted by ollien

And that will hold? Is there a stronger alternative?

Bigger chain, bigger bolts. #35 chain fits #8 bolts, I think. Not sure if the extra weight is worth the gain in strength though.

[hectorcastillo]

Originally Posted by Chak

Bigger chain, bigger bolts. #35 chain fits #8 bolts, I think. Not sure if the extra weight is worth the gain in strength though.

Thanks for bringing that up, Chak. I completely forgot about #35 chain. We used #25 to make our climber as light as possible, but #35 is definitely a great and probably more reliable option.

[Steven Smith]

VexPro sells a gusset with the intended use case. You could easily make something similar, but their drawings explain it well.

http://content.vexrobotics.com/vexpr...00-Release.PDF

[ollien]

Originally Posted by Steven Smith

VexPro sells a gusset with the intended use case. You could easily make something similar, but their drawings explain it well.

http://content.vexrobotics.com/vexpr...00-Release.PDF

Neat! Thank you!

[Monochron]

Here is an example of what we did for our elevator last year. We used T-Gussets bought from Vex and bent them 90 degrees to give us plenty of mounting room. To attach the gusset to the chain we used two #8 bolts, which fit through #35 chain (use more #4 bolts if you are using #25 chain), which seemed to provide plenty of support.

[jnicho15]

548 used those McMaster attachment links last year to mount our tote hooks to our lifting chain (which also had a guide rail). This year, we are using them to hold the end of the springs that balances our arm.

[BBray_T1296]

Link to mcmaster's selection of attachment links. Only for #35 (or larger) though.

[Dominick Ferone]

Originally Posted by ollien

I've been googling around about this for the past couple of hours, but I can't seem to wrap my head around how teams are utilizing chains for linear motion. Currently, the best item I can find to do something like this would be something like this But my gut tells me that these would be rather fragile for anything more than a few pounds. If I wanted to move a load along a chain, how would I best accomplish this?

We used these back in 2013, and we had hardened steel 6-32 bolts. They could withstand 600 pounds of force before sheering. We never had a problem with them. We actually damaged the hook and the chain and bolts were fine.