topic Re: need 2 joints on same components in Fusion Design, Validate & Document Forum

need 2 joints on same components

David_Ewen — Wed, 31 Jan 2018 00:08:47 GMT

I'm coming from Solidworks where I used to be able to create this type of joint.

I have 2 tubes that are S shaped, 16" apart at the bottom, but I need them 22" apart at the top. (Think of a shopping cart) I'm making something similar. Attached is a screen shot from a model done in Solidworks.

Any ideas?

Re: need 2 joints on same components

Zero__ — Wed, 31 Jan 2018 00:15:01 GMT

I can't quite visualize it, and it looks like your pictures didn't work. Try reattaching them? Or upload them to imgur?

If they're pivoting about a point, you should be able to use a cylindrical joint. Otherwise, Rigid and appropriate offsets may get you there. I'll be able to help more once I see the pic!

Re: need 2 joints on same components

David_Ewen — Wed, 31 Jan 2018 00:17:33 GMT

I thought a little more background would be useful.

How I created these joints (align in Solidworks)

First I would align each lower long portion to the XZ plane, so they are aligned on the same plane.

Second I would tangent align each of the long lower end 8" from the YZ plane or the Z axis (either works) to get the total of 16"

Then I do the same with the short upper portion at 11" from the YZ plane or the Z axis

Re: need 2 joints on same components

David_Ewen — Wed, 31 Jan 2018 00:19:31 GMT

Here's the full pdf version from Solidworks.

Re: need 2 joints on same components

Zero__ — Wed, 31 Jan 2018 00:36:54 GMT

Interesting...

Ok, so first I would decide which part in this assembly is the Ground (is fixed, or not moving). Technically you should never need more than one joint to fix two components together, even if they are moving. But sometimes I cheat and use two. My first thought: use that lower plate, or either of the two flat cross beams, as your ground and simply fix your S-bars with two cylindrical joints. That's assuming the S-bars have holes in them that bolt to the flat plates. Or are they welded? I don't see holes in your pdf.

If your S-bars have no holes in them to easily joint to, this gets a little trickier. Fusion doesn't do much with tangent surfaces and joints. You could try creating your own Joint Origin, but off the top of my head I'm not sure how it would help you here.

I, personally, am not above a bit of cheating. Such as creating a tiny flat where you want your S-bar to mate to your flat crossbeam plate and Jointing them together there. Visually imperceptible in your mechanical drawing but gets the job done.

Re: need 2 joints on same components

David_Ewen — Wed, 31 Jan 2018 00:48:57 GMT

looks like it's going to get tricky.

These type of multiple mates in Soldworks are easy because I can use planes or the XYZ axis. I'm really struggling with Fusion. Fusion is so much easier on many other levels though.

Ok. More info.

All other mates (joints) are associated to the S-Bars. I need them to be grounded with the 2 different widths.

The reason is that all the other components need to be moved around to balance the assembly.

Everything is welded. No bolts. At least on what you see here. There will be a few more components added that get bolted.

Re: need 2 joints on same components

Zero__ — Wed, 31 Jan 2018 00:53:39 GMT

Here's an idea. Are the flat ends of your S-bars in the same plane? You could grab the center Joint Origin of the top and bottom and set a Planar Offset. Then you should be able to do the same to the top or bottom pair, depending on which you started with.

Grab the center Joint Origins of your top pair, set their planar offset to 21.75. Then repeat with the bottom pair and set to 16. That may not constrain all degrees of freedom..but if it's looking right you can them ground one of them.

If you want to upload a step file of one of the S bars I can play around with it.

Re: need 2 joints on same components

David_Ewen — Wed, 31 Jan 2018 15:55:45 GMT

Thanks for the help.

I've uploaded both a .step and .f3d file for you.

Re: need 2 joints on same components

jeff_strater — Wed, 31 Jan 2018 16:22:32 GMT

The model that you shared contains only one component and one body. You need at least two components to create a joint (true in Fusion as well as Solidworks). Are there other components in your design, or are you asking how to change segments of the pipe in this one body, which would involve editing the path sketch?

Re: need 2 joints on same components

David_Ewen — Wed, 31 Jan 2018 17:07:22 GMT

Jeff,

Here are the steps I take.

Step 1, insert the component.

Step 2, copy or insert a 2nd instance of the same component. (2 of the same are used for this step)

Step 3, in Solidworks, I mate the long portion of tube1 to the YZ plane at 8"

Step 4, in Solidworks, I mate the long portion of tube2 to the YZ plane at 8"

this gives me the 16" OC between the tubes that you see on the PDF that I uploaded.

Step 5, in Solidworks, I mate the short portion of tube1 to the YZ plane at 11"

Step 6, in Solidworks, I mate the short portion of tube2 to the YZ plane at 11"

This gives me the 22" OC between the tubes that you see on the PDF that I uploaded.

Step 7, add the flat plate and using tangent mates in Solidworks, mate the plate to the long portion of both tubes.

Step 8, continue adding components and mating them.

final steps - inspect mass weight and move the flat plate and 3/4" axles to balance all the weight between the front set and rear set of wheels.

Re: need 2 joints on same components

Zero__ — Wed, 31 Jan 2018 18:53:56 GMT

David - here's what I did which I think gives you what you want.

I opened up your component. I went to the Move command, then selected the center point of the bottom hole. In the picture, it's at the Origin (red and green lines intersecting). I rotated your part by 5.2 degrees relative to this point.

After that, I simply created an offset construction plane 8 inches away, and mirrored the component about it. Bam, done. Then you can Ground both components so they won't move.

Now I just eyeballed the angle and you'd want to do 30 second's worth of trigonometry to properly calculate it. The distance between the centers of the bottom holes is a true 16 while up top it's about 21.802 or something like that.