CAM mechanism appropriate?

[JDBlanck]

The orange piece is free to rotate in the dark green base.


The blue cylinder is free to rotate along its axis.


The gray piece is permanently fixed to the blue cylnder


The light green cylinder is permanently fixed to the green base.


My goal it to raise the orange piece so that the blue cylinder is perpendicular to the green base, thus causing the gray piece to strike the light green cylinder which in turn will cause the blue cylinder to rotate.


I have tried (and failed) to create the desired movement by creating a cam connection between the light green and grey pieces with liftoff enabled.


Any sugestions would be appreciated.


View attachment 5552

 

[msummers]

Nice little problem. I will be interested to hear the proposed solutions...

 

[Kaz Z06]

John,


Cams will not work for this application since your mechanism operates in 3D. Cams only work in one plane, requiring the contacting curvature of theirbodies to be extruded in the same direction. You will need to use "3D Contact" to solve this problem. 3D contact was introduced in WF5.


Good Luck,


Chris

 

[SRINIVASANIYER1]

Cams will not work for this application since your mechanism operates in 3D. Cams only work in one plane, requiring the contacting curvature of theirbodies to be extruded in the same direction.

Not quite true. e.g a Barrel cam.


As for the problem...


Attached is the Zip file for the Mechanism components. Since the base is part of the FIXED LINK, it has not been modelled.


2012-03-02_015629_CAM_MOTION.zip


The avi file and the Analysis file included in the below link (Size larger than 2 MB and hence cannot post) depicts the mechanism analysis with 3D contact and an audible bell for Clash Detection.

 

[Kaz Z06]

Srini,<?:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" />


Please read the help topic on cams - they are only for useby 2D cam-follower applications. You must use 3D Contact to get the problem described by Johnto work, you cannot use cam-paired connections. You did not apply the connections properly for the model you posted in your comment - you cannot apply a cam-pair connection AND a 3D Contact pair together and say the cam connection works! The 3D contact is the only connection that makes your model work. Remove the 3D Contact definition and you will find that the cam connection by itself will not work for this model. As I've stated before, cams will not provide the desired motion for this type of contact - 3D Contact must be used for 3D situations.


Chris