topic Joint Advice in Fusion Design, Validate & Document Forum

Joint Advice

Anonymous — Sun, 08 Jan 2017 15:24:31 GMT

Hello

I am trying to assemble a type of scissor jack and I am having trouble constraining the rotation of the components that do not need to spin.

When I turn the input hex to expand the jack....the entire model spins with the screw. How do I hold the links flat so the screw will turn, the cyl mates will engage and the jack will open?

I need to constrain the links parallel with a plane to limit rotation. Similar to if you modeled a bolt and nut. You want to be able to spin the bolt head and have the nut travel on the threaded portion at the specified pitch.

After you assign the revolute mate to bolt (and origin) and cyl mate to nut and bolt.....if you spin the bolt the nut rotates too. How to constrain the bolt so it does not rotate BUT will travel along the long axis at the specified pitch per rev.

Thanks

Re: Joint Advice

TheCADWhisperer — Sun, 08 Jan 2017 15:26:06 GMT

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

Re: Joint Advice

Anonymous — Sun, 08 Jan 2017 15:55:54 GMT

Yes. Thank you kindly.

Re: Joint Advice

jeff_strater — Mon, 09 Jan 2017 02:44:25 GMT

Thanks for your patience, @Anonymous,

I was able to get this joint system to work. The biggest problem, I think, was applying the joints after the thread features. The geometry in a threaded cylinder is very complex, and it can give the joint solver fits. So, I moved the threads to the very end of the design, and inserted the joints before those threads. Here is a long-ish screencast showing how I was able to do this:

I've attached the fixed model, in the meantime.

Hope this helps,

Jeff

Re: Joint Advice

Beyondforce — Mon, 09 Jan 2017 03:24:50 GMT

Hi @Anonymous,

Here you go. Please next time, create the components In-place. I have attached the file as well.

Cheers / Ben
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Re: Joint Advice

Anonymous — Mon, 09 Jan 2017 23:40:17 GMT

Hi @Beyondforce

Thank you... that is exactly what I was looking for.

What do you mean by "next time create the components in place?"

Are you a pilot? (looking at your picture)

Re: Joint Advice

Beyondforce — Tue, 10 Jan 2017 03:21:40 GMT

When creating a component in an assembly, you create it where it's suppose to be. If you create a bolt and a nut, then you create the nut around the bolt in the right position. Correct me if I'm wrong, but it seems like, you have imported some of the parts and you broke the link right after (which is the right way).

No, I don't work as a Pilot, but I do hold a Commercial Pilot license 🙂

If you have a question about the joints and the file I sent you, please let me know.

Ben.

Re: Joint Advice

Anonymous — Tue, 10 Jan 2017 04:09:26 GMT

Awesome. No I didn't import anything....I did copy and paste the redundant components.

I'm a pilot too. Not professionally but I too have my commercial license. I mostly fly a Saratoga TC.

Thanks again for the help.

I noticed you created a dummy component to use for the slider joint.
I took your idea and instead of creating a dummy component to use for the slider and then hide....I created a joint origin at the origin and that worked for the slider joint.

Re: Joint Advice

Beyondforce — Tue, 10 Jan 2017 14:30:00 GMT

A Saratoga TC, that's a nice one. Are you trying to make me jealous? 😉

The a joint origin sounds like a better idea. I'm glad you figure it out.

Ben.