topic Re: Moving/aligning objects which have linked revolute joints in Fusion Design, Validate & Document Forum

Moving/aligning objects which have linked revolute joints

Anonymous — Sat, 25 Feb 2017 06:55:32 GMT

Hi,

I have a problem in which I have two linked revolute joints. It's kind of hard to explain in words, so I have attached an example file.

I have two "blocks" in this file, one bigger and one smaller, each attached to a cylinder coming out of one side. The revolute joints are configured with a motion link in such that the two cylinders are basically rolling around each other, keeping faces of both blocks parallel no matter what angle the joint is driven at.

I'm trying to make clearance distance between the two blocks exactly 30mm in the positive Z direction, without deleting the revolute joints or the link. This would require driving the revolute joints to an arbitrary angle. I know how to do this in inventor (easily!), but I cannot for the life of me work out how to do it in fusion 360.

My latest idea was to use the align tool to align the two inner large faces of the blocks, and then use the move tool to translate it up by Z=30mm. Then I could use an as-built joint. However, using the align tool doesn't actually do anything when I select the two faces. (I've never actually used the align tool, so I am not sure how this is supposed to work).

I have considered two unacceptable solutions:

- calculating the angle by hand; I don't want to hardcode the angle.

- creating a large spacer of thickness 30mm; I don't want to have a spacer in my design which is not a real part, and it will certainly confuse people who look at it later.

Can anyone please help me with this?

Thanks,

Jeremy

Re: Moving/aligning objects which have linked revolute joints

TrippyLighting — Sat, 25 Feb 2017 11:45:41 GMT

Perhaps you can make a screencast and explain that better.

The way you currently have designed this the top surface of the Component1 block and the bottom surface of your Component2 are already 30mm apart in positive Z (up) direction, but only wen the joint angle is exactly 90 degrees. I am not sure why you would need to drive the joint to an arbitrary angle to do this.

Re: Moving/aligning objects which have linked revolute joints

Anonymous — Sat, 25 Feb 2017 13:23:16 GMT

Whoops, that's what you get for writing while you are tired! I meant that the spacing should be 25mm, not 30mm.

But still, the problem I am interested in solving is: how do I tell fusion 360 to move the faces apart by a linear distance, and have it automatically compute the angle for the joints? In inventor, you would just create a flush/mate constraint between the two faces and set the offset to 25mm (or 30mm, or 24.36346mm, etc) and it would do it for you.

I will try to do a screencast tomorrow if I get a chance.

Thanks,

Jeremy

Re: Moving/aligning objects which have linked revolute joints

TrippyLighting — Sat, 25 Feb 2017 13:29:22 GMT

Aha, so if you constrain these faces to be apart a static 25mm ad the joints are 30mm apart you'd get a resultant angle.

I am wondering why you cannot do that with a simple parametric sketch ?

Re: Moving/aligning objects which have linked revolute joints

Anonymous — Sat, 25 Feb 2017 13:33:16 GMT

Is it possible to constrain separate components using a sketch? I was not aware of this. I will try to have a look.

Re: Moving/aligning objects which have linked revolute joints

Noah_Katz — Mon, 27 Feb 2017 02:35:12 GMT

> I am wondering why you cannot do that with a simple parametric sketch ?

Do you mean go back and recreate the components using such a sketch, or is there a way to constrain components to a sketch created after they were?

I'm just starting to work on juggling created and imported components within an assembly and was wondering if I could use sketches to maintain minimum clearances, as joints seem more suited to parts that fit together.