Pins and slots on cylinders

[tonyc]

I understand now that pins in slots move nicely when they are mated with a "transitional" mate and there are reasonable tolerances. That's good news.

 

I run into trouble now when I apply that technique to two slotted cylinders that spin in order to drive pins.

 

Any suggestions? Thanks for looking.

 

Cylinder Slots.zip

 

Post script:

The attachment is no longer STEP files. Now these are good inventor files with the end of part marker moved up. Also, the tangency mate has been replaced with a transitional.

Before making formal reply to the posted suggestions by JD Mather, I will work on creating slotted cylinders as in the example that were given.

 

P.P.S.

 

O.K. - I have got an answer!!

 

1 - Mate, transitional, the pin to the SURFACE on the cylindrical cam (the surface made in the creation of that cylinder with a wave shape slot). NOT the surface of the part.

2 - Mate a work point of the pin to a vertical work axis of the straight-slot cylinder. (rather than a tangent of the pin to a post in the center). This might be necessary to allow the pin to move more freely?

3 - Mate the Z-axis of the pin to the plane that bisects the vertical slot.

4 - Beware that the transitional mate is very finicky. Get everything into place as gently as possible, put the other mates into effect first, then suppress them, then make the transitional mate, then un-suppress the first two mates

 

The assembly file size is too large to attach here.

[JD Mather]

Why did you convert the inventor files to STEP?

If it was to reduce file size you could have done that by simply dragging the red End of Part marker to the top of the browser. The cylindrical cam must be created with very specific steps to work (on the complex path).

 

It is far easier to do now (in r2010 Design Accelerator), but you might check this tutorial to see just what is involved. http://home.pct.edu/~jmather/content/DSG322/Inventor%20Tutorials/Inventor%2011%20Tutorial%2011.pdf

 

And what is with the Tangent between pin and cam? I thought we already covered that ground - tangent is not going to work. Tip: Don't have time right now to get yours working (and without the history tree not sure your slot is correct so don't want to spend time checking) but sometimes you need to create a surface body sphere or hemisphere to get it all to work correctly).

 

Another option is to use Dynamic Simulation if you have Inventor Professional. Far easier to do the motion.