slot mechanism gets stuck in corner

[AlexK]

Hello community

I'm working on a mechanism where a tray gets held in position by a slot connection.

When the pin reaches the turning point in the curve, the parts get stuck:

Is there any way to avoid this problem?

Thanks for your help!

Best wishes

Alex

[MartinHanak · Accepted solution]

Hi,

I don't know much about mechanisms, but try the following...

• select curve you use as slot constraint reference (I guess it contains two straight lines and single arc)
• CTRL+C
• CTRL+V
• set Approximate option and finish Copy feature
• redefine slot constraint ... use the curve created via Copy feature
• test Drag operation

[MartinHanak]

see video showing my test assembly.

[AlexK]

Hi Martin

Thanks! This solution made it work, and I can move it now without crashing.

Best wishes

Alex

[kdirth]

In my experience whether you are dragging the "shelf" or the "link", the connection does not know which way to go at the apex of the curve.  You have to switch to dragging the other part to get the connection to continue.

[kdirth]

Here is a video of moving the attached simple model (7.0)

[AlexK]

Thanks! you are right, it has to be moved in two steps. the problem was, that the mechanism had an error and wouldn't move any more. Martins solution fixed that.

[pausob]

Hmm, I am thinking that this mechanism goes through a so-called "singularity" somewhere along that rounded corner in the slot path.

One of the effects could be that the mechanism motion is impossible for the driving link to maintain - so further progression along the slot path is possible only by switching to dragging the other link.  Anyway, that's kind of how this will work in real life, no?  I envision a 2-handed operation is needed to "put away" this shelf...