Pin-Slot Joint Troubles

[Anonymous]

I'm trying to build an assembly around the relative motion of two objects. So I want to get the relative motion working between the two objects using joints and then design the rest of the assembly around that motion but I can't seem to get joints to do what I want.

• The joint origin of the lower object should move along the upper axis
• The x-axis of the joint origin should remain parallel to the lower axis
• The lower object should be able to rotate around its z-axis

I've tried all sorts of pin and slot joints with different joint origins but I can't seem to make it work. I've attached the .f3d as a starting point, any help would be appreciated.

[davebYYPCU]

So far, your picture doesn’t accord with the Instructions.

you have 2 axis, and 2 blocks.

Both axis Intersect with the back block at its centre point.  

I take it the front block is sliding towards the back block along the lower axis, while the top axis is guiding the rotation.

Right?

Use Cylindrical Joint, and a Motion Link, to tie the sliding distance to the rotation.

Same as a course pitch nut on a bolt. In your case a finger is added to the nut.

Not reviewed the file yet.

If I am wrong I don’t mind more info.

Might help....

[Anonymous]

@davebYYPCU sorry if my descriptions were a bit confusing.

I got the kind of motion I want but I haven't figured out how to align it.
In this screencast the block's rotation and facing is ideal but it needs to travel on the other axis:
https://knowledge.autodesk.com/community/screencast/b392b4ce-8aa5-4e94-9cbd-58ec4cbdf1d3

I've tried selecting either axis for the "sliding axis" in the pin-slot joint I used but the motion is the same for both axis. Try it for yourself in this assembly:

[davebYYPCU]

I have watched the video.  Let’s say you hide the other block.

They were not at all involved in the video.

What has to happen as it relates to the second axis.  If the 2 axis converge to a crossing point, what part of the moving block going to attach to that second axis.

Will check the file for more clues.

[Anonymous]

@davebYYPCU I think I see where you're going with this, are you encouraging me to reposition the other block?

It would solve any facing issues, but my main problem remains: the axis of travel is still perpendicular to the axis of rotation. This is not the motion I'm trying to achieve. In this example, the axis of rotation should be 25 degrees away from perpendicular to the axis of travel.

Thanks for helping me clarify.

[davebYYPCU]

So far, I am thinking you want the spinning plate, to align to the red line as well?

Thinking.....

[Anonymous]

@davebYYPCU no.

The rotation and facing of the block is correct it should just move along the other axis, like this:

[davebYYPCU · Accepted solution]

I think I have it as you wish, 

some changes to get there,  I don't use Joint origins if I can get away without them, 

I have a new Centre line in the second component block sketch.  

Made a new Pin Slot, (editing the old one was not working for me)

and selected the end of the centre line, with Z up.  I selected the end of the correct construction line, with Z up.  The dialogue box allows for the (-50) rotate, and the Custom Slider direction is the Axis 1.

Looks weird, but is doing what I think you are looking for.

I would put it down to the Joint Origin not able to orientate to the angle you wanted.

Might help....

[Anonymous]

Awesome. Thank you so much, it worked!