Mechanism physical properties

[fredws]

I have an assembly set up with linkages, hooked to a hydraulic cylinder. I can drag the parts in Mechanism, and the linkages work fine, but the problem I am having is that the linkages can swing backwards and go through the mounting plate. How do I tell Mechanism that it can not pass through the solid beam?



TIA

 

[noppenbd]

In the Mechanism menu, under Model, select Jt Axis Settings. Then select the yellow Joint Axis for the linkage in question. Select the Limits tab and you can specify angular limits for the axis. The only trick is establishing a zero, which you can do on the Zero Refs tab.



Hope this helps.

 

[xcad]

use the mechanism drag option to align the two surfaces (the surfaces you want to set as the upper or down limit to your mechanism).

then set this position as zero

with this way you have set a limit to your mechanism



xcad

 

[fredws]

Is there any way to tell it that it can't go through another body?

Using your help, I got the limits set on the first linkage, but can't seem to get it to work on the second, because as the first linkage pivots around, the angle is different on the second.



Maybe if I explain a little better it would help. What I have is basicly a T made of two linkages(pinned) The bottom of the T is pinned to a mount on a beam, one side of the top part of the T is pinned to a hydraulic cylinder. In the real world, there are certain physical constraints, the linkage can not swing back around and go through the cylinder, or the beam, or etc. I set the angle limits on the vertical part of the T, and that part works fine, but having problems setting the cylinder, and the top part of the T.



Thanks

 

[noppenbd]

Well, first things first, make sure you have your limits set properly. The references should be such that it does not matter how the other components move. In other words, for the top part of the T, pick:

1) a datum plane or surface on the vertical link

and 2) a datum plane or surface on the top link.



Also, to set the translation limits on the cylinder, make sure you query select when you pick the joint axis. You should pick the second selection. That will be the translation.



If you have these right we can talk more specifics.