Issue with pattern within an assembly

[nige106]

Hi, I'm trying to create a chain along a path. I'm part way there but now totally stuck. For some reason the links don't seem to follow the curve precisely, but once past the curve evrything is back as it should be. I think it's an issue with what I'm constraining the first link to.... maybe.

In the attached file ignore the fact the links aren't at 90deg to each other.

Thanks.

[yannicknielsen]

I can give you an explanation, and possibly a fix that can make it behave like you want.

As for the explanation, it is because of the way inventor works. When you follow a pattern on a curve, your parts will start rotating like the curve.
On the first part of the line, they're vertical like the line. When it comes to the curve, instead of attaching to the next points, it follows the curve.

If you draw a line to every point, in the curve, you'll see that it has a 90 degree angle to the chain link. That is because, when you follow such a pattern, the part will rotate as much as the curve, so if it has a 20 degree angle in the next point, so will the part.

Now for the possible fix. You can do it one of two ways that I can come up with at the moment.

If you, instead of having your points where you have them now, make one in the middle of the link, it will behave a bit different on the curve.

The other thing you can do, is to manually place some of the links, and attach them to both points

[nige106]

Thanks for the reply.

Moving the point to the centre does look slightly better, but it's still quite obvious it's not right in my renders.

I didn't want to go through the manual placing option if i'm honest.

I've downloaded a couple of other people bike chain assemblies and they seem to have the same isses but as the centres are a lot closer the issue isn't as apparent. Is this impossible to achieve with Inventor?

[JDMather]

Instead of following an arc (your links don't bend) I think you need the chords along the arc.

I would do the arc as construction and try adding the chords.

Double check this as I did it real quick.  I didn't bother moving the connection to center of links.

[nige106]

Could I ask you to take the time to create a small sketch if possible. I thought I understood your explanation, yet it still didn't work as I expected.

Thank you.

[nige106]

Ignore my response, you've added more to your post.

[JDMather]

I went back and double-checked and I didn't do it exactly correct, but I think my example should get you going in the right direction.

[nige106]

I've got a solution to my problem that worked well enough.

Thanks for your time looking at it. out of interest what is it you'd change still?