Accurate looking roller chain

[pball]

I'm trying to create some accurate looking roller chain because why not. I can get one of the links patterned nicely along a closed path but the second link doesn't follow the curve like it should in real life. I believe the issue is the position relative to the start of the curve on the path, but I don't see how to fix it.

Attached file is 2020.

[e_paquette]

I wouldn't start without a base sprocket. Chains are a pain for a couple reasons. In order to get accurate movement, you need to have 1 DoF per link. That quickly builds into a very unstable and slow reacting model. I placed my sprockets where I wanted the with rotation freedom. Then built the straight section as a pattern, rotated to match the sprocket to get the under tension look. Pattern around the sprocket. Attached are a couple of screen pics of a project I'm working on. I have three total chains, one is a pattern of the other with the shorter chain acting in conjunction with the end chains to make sure everything is tight.

If you just want the chain without the sprocket, suppress the sprocket or ground the chain and delete the sprocket. Either way, align each pin in the link with the next and use the center plane to keep the links centered on each other.

[e_paquette]

Second screen shot because of course you can't upload more than one.

[pball]

Maybe I should have clarified but I am not looking for a functional assembly of chain links. I just want a single part that looks like an accurate loop of chain. If you open the part I attached you should see what I'm looking for.

[e_paquette]

I get what you are saying. I think putting in a sprocket, using that for your constraints for the circular portion, grounding links, then pattern and deleting the sprocket will be the fastest/easiest way.

[JDMather]

No sprocket is needed.

Only sketch path for curve driven pattern is needed.

[pball]

@e_paquetteI don't have an assembly so what you are describing does not help me.

Please look at the file attached in the first post if you have not.

[TheCADWhisperer]

Take a look at the Attached -  I made some changes - but I don't have correct just yet.

I have a spreadsheet to calculate the exact path length and number of Pin Links and Roller Links, 

but I need to know the number of teeth on each sprocket and is this center-to-center distance absolute 57.5, or can it be adjusted?

If it cannot be adjusted - I will need to add catenary curve (can't make a chain too short, but can have slack).

[pball]

The large end is a 22 tooth sprocket while the small end is just a Delrin guide so it could be any size really. As for the distance between them, that isn't critical either. I was planning to fix the chain length after figuring out how to pattern the links better.

Just in case any is wondering this is for transferring lightweight product at slow speeds, which is why there isn't a sprocket on the one end.

[andrewdroth · Accepted solution]

Working off of @JDMather 's part I added some user parameters and reference lines to sketch 5 in order to gather the minumum number of links for the sprocket layout. I also added some chain slack.

I used the midpoints of the chain links to start the patterns rather than the pin locations. This makes the chain 'look' more correct, but it should be noted that the pins won't line up exactly. I bet it's close enough for what you want though.

[pball]

@andrewdroth 

Thanks for sharing. This should be more than good enough to make my model look pretty. I don't believe I've played with the direction start option in patterns and that is the secret sauce in this scenario.

I like what you did with the sketch to calculate the chain length. I've done something similar but messier as I just added all the line/arc lengths together in a parameter, using a sketch like that seems much neater and easier to manage.

[andrewdroth]

@pball Thanks. I'm in the process of putting together a YouTube video describing the different ways sketches can be used as calculators. This would be a good example.

[JDMather]

I think this can be animated as well, perhaps within a single part file without any assembly component pattern, but I haven't had a chance yet to experiment beyond one link.

Would be a good exercise for your YouTube video.