setting motion limits on ball joints

[2ms1]

The ball joint connection type does not have joint settings. This means that, unless you additionally have something else like a cam follower or something, any thing attached to a ball joint can just rotate the full sphere as if there was nothing in the way.


A tutorial I was looking at suggested using a cam follower. So I that, but then it contraints the motion to always being on thecam path. So, for example, the "stick" shown below can't even stand straight up -- it always has to be leaning on the cam curve.


How do you get a ball joint to work as a proper ball joint with outside limits on its motion, but freedom within those limits?


View attachment 4338
Edited by: 2ms1

 

[Kaz Z06]

2ms1,


I can help here - first, I would highly recommend that these types of posts be placed in the "Analysis" portion of the Pro/Engineer Forum, this will help to get the attention of those of us focusing on the CAEaspect of the tool set in Pro/E. The reason you cannot set limits to the DOFs is ball joints do not have any sense of "direction". A ball joint is the most simple form of 3 rotation DOF and 0 DOF translation joint. PTC never associated, or oriented, a ball joint with a coordinate system, so you cannot apply rotation limits or obtain any result measure along a specified direction. But,there is hope! If you use a 6DOF joint in place of the ball, you can lock the 3 translational directions and arrive at the same constraint set as a ball joint AND possess the ability to set limits and obtain result info along the coord directions. This should solve your problem.


Cheers,


Kaz Z06

 

[krahmk]

Another way of handling this issue is to use two perpindicular pin joints and set limits on their motion. This is easy and works great. However you may need a dummy part with only datum planes and an axis in the assy to give you the independent motion.


HTH


Karl

 

[shankar_me]

Hi 2ms1,


In the camconnectionthat you gave, in the definition dialog box, go to properties tab and select "Enable Liftoff". This allows you to move the handle freely in the way you want.


shankar