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Cam (?) Question

A

amoncur

New member
I'm trying to run a Mechanism analysis with a part that needs to translate and rotate at the same time; however, I don't know how to specify the correct path. I think using a cam/follower connection somehow would work, but I haven't been able to figure it out yet.



View attachment 161

This part is stationary. The other part fits inside and I want it to rotate about the follower path I have specified.





View attachment 162

This is the part which fits inside the first, and rotates and translates. The circular datum curve is what (I thought) would be used for the cam follower connection, but it isn't working.



View attachment 163

This is what the parts look like assembled together. As you can see, the green part has to rotate and translate at the same time.



Any ideas on how to do this?



Thanks,



Aaron
 
I've experimented a little more and been able to use a bearing connection using a point on one part and a straight datum curve on the other part. This lets me traverse the point-part across the datum-curve-part, which is what I want-a point on one part following a specified path on the other. However, I can't get this connection to work with a curved datum-curve, as I need to in my assembly. Do you need to travel along a straight path when using a bearing connection, or am I just messing up somewhere when trying to do it with a curved datum?



thanks,



aaron
 
Amoncur,



First of all: hold your horses! Don't get too excited over nothing! I have initiated a number of posts here that were read a lot of times but I got exactly zero answers! On some posts I got an answer within a few hours. Nothing to get mad about. Have you considered the fact that it might very well be that nobody who read your question knew the answer...?



Anyway, to your question.

I am not at my Pro/E pc right now so I am writing this out of my head.

First of all: constrain the parts in the assembly as a mechanism. I think you have done that, but I don't know if you have used the correct connection. I think you need a slider in this case: it must allow one translation and a rotation around that axis.

You can check out if this is what you need by going to 'mechanism' and try to drag the parts by hand. See if they make the correct movements (1 translation, 1 rotation).



Second:

The red part should get a datum curve in the center of the groove. Several ways to create the datum curve, but I would use a 'formed datum curve' (in Pro/E 2000i2) or in case you use WildFire, it is called a 'Wrap' feature.

So you must create a datum curve 'around' the red part. This curve is the path that the green part must follow.



Third:

In the green part you must define a datum point that must travel over the datum curve of the red part. Important: the datum point must lie exactly on the curve, so the radius to the axis must be exactly the same as the radius of the datum curve.



Fourth:

Now define a cam-follower combination. The datum curve on the red part is the cam. The datum point on the green part is the follower.



When you now drag the green part in 'mechanism', it should perform the exact movement that you want.



To make it move automatically, you need to define a driver, which is another matter...



Hope this helps ... a bit..:)



Kind regards

Eddy
 
Eddy, thanks a lot for your reply. Just so you know (and anyone else who might read this), my first reply was a joke. I was playing off LNagys previous post. Just a joke, I'm not really upset.



Eddy, thanks again for your help.
 
How do you get a slider connection to allow rotation? I specify the translation axis and it prompts me to specify two planar surfaces to prevent rotation. Is there a way to use a slider without constraining rotation? Should I be using a cylinder connection instead?



When i use a cylinder connection along with the datum curve and point you mentioned above, I get an error message when trying to specify the curve on the red piece as the first cam. It says Please select some cam geometry. ???
 
Like I said. I was typing out of my head. Yes, I think you need to use a cylinder instead of a slider.



I'll try to experiment here to see about the cam follower.
 
Aaron,

Seems like my memory was playing tricks on me..

You do NOT need the 'Model/Cams' option, but the 'Model/Slots' option.

This allows you to select a datum curve and a datum point.

The datum point travels over the datum curve.

I just put together a small example. Should you continue to run into difficulties, drop me an e-mail and I will mail you the sample files.



Kind regards

Eddy

e-mail: raimundo4u (at) yahoo (dot) com
 
It's clear that amoncur is some primadona bee-otch that needs to calm down and realize that every member in this forum is not his personal slave. You better back down before you catch a beat-down you little whining zoobie!
 
Hey mit_joel, did you actually read the thread?????



>>Eddy, thanks a lot for your reply. Just so you know (and anyone else who might read this), my first reply was a joke. I was playing off LNagys previous post. Just a joke, I'm not really upset.
 
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