Screw that ROTATEs-while block SLIDEs

[JayWBeck]

I am having a difficult time of getting the joint definitions correct to make the screw turn and the shelf slide up and down on the back wall.

I believe I need a SLIDE and ROTATE joint + a MOTION-LINK to then tie the 2 joints together.

I can define both independently but then I can’t get the Motion Link to accept the joints, it keeps saying there are joint conflicts but of course, no details.

I have tried different schemes using different locations to define each of the joints and their alignment.

I have tried using the CYLINDRICAL joint BUT it seems to force the assumption that the 1st component picked is the one that will rotate as well as going up and down the 2nd component picked.

What I want is the 1st component to only side up and down and the 2nd component to only rotate.  That is what keeps leading me back to separate SLIDE and ROTATE joint definitions.

I’d appreciate guidance on an approach to this problem.

[jhackney1972 · Accepted solution]

You had an extra Slider joint and needed to have a rotational joint located the screw to the assembly.  I did this with a point sketch and then a Revolve joint to it.  I am not sure I have the ratio right on the motion link, it look right.  Take a look at the Screencast.  Model is attached.

[laughingcreek · Accepted solution]

1-having those ground and un-grounds in your timeline isn't doing you any favors.  instead of un-grounding, just delete the original from the time line.  in the attached I delete all and then grounded the block

2-you built everything in place, so you can use "as build" joints, which are generally easier to deal with.  the shelf has a as built to the block as a slider, and the screw has an as built joint to the block as a revolute.  no need to add anything else.

3-I delete the hole command and added a seperate extrude and thread command for the shelf.  for some reason threads from the hole command didn't line up with threads on the drive screw, which was buggin me.

[JayWBeck]

Thanks again for the help.

I was able to get it working with my version and with your hints.

The hardest for me was figuring out what you meant by creating a point in a sketch and applying a rotation constraint.

It took me a while to figure out I needed to create a sketch for a point associated with the back wall by first making the back wall component the only one 'active', then drawing the location of the point.  Since my version of where the screw was located was also offset vertically from the back wall, I needed a point 2 mm higher and 2.5mm from the front wall's edge center location.  Also since the wall sets 2mm below my origin, I simply needed to add a point 2.5" from the origin. I applied the "Lock" constraint to the point.  (I assume this is what you meant by a 'rotation' restraint.  Anyway, it all worked fine.

As you can tell, I'm recreating your demo of using motion links.  I'm enjoying using the motion links and learning about meshing the gears (found the add-on tool), and the offset screw and block --, and we'll see what-else as I work to finish the lesson.

[JayWBeck]

Thanks so much for the suggestions - I've been able to get mine to work.