Sweep using guide rail on curved surface for toroidal cam

[Anonymous]

I'm trying to design a mechanical structure where I have a disk "cam" that pivots a pendulum in a specified  repeating sequence.  Think of this as an automaton wheel cam that drives  a pivoting pendulum.  For the pendulum, I have a short lever with a ball on the end, that I want to be driven by a wheel.  The pendulum will have a fixed pivot point and will rotate back and forth based on the shape of the cam slot  I want the pendulum's short lever with the ball to slide in a groove in a wheel cam.  This wheel cam should be designed so that it rotates about a central axis and drives the pendulum back and forth by ~45 degrees as the wheel rotates.

To do this, I created a toroidal surface to project the path that the end of the short lever should swing.  To cut the groove in the wheel, I'm trying to use a sweep with a guide path to create the groove, but I haven't figured out how to make it work properly.  Several of the sweeps (see attached file) have kinks in them so there isn't actually enough room for the pivot ball and rod to fit inside the path that is created.  In the image below, I am showing one version using "SOLID" sweep, this version seems to create enough room for the lever and ball to slide, but it can't get the software to sweep across the complete path, so I can't finish the full loop of the sweep.  The included Fusion 360 file has several "New bodies" created with the "SOLID" and "SURFACE" workspaces so that you can compare the different (and often strange) results.  

In general, this seems a similar challenge to "machine a slot with a ball endmill"  but I still can't get it to work properly.  I appreciate any help you can provide.  This is my first time asking a question on the forum.  I've searched but can't seem to find this exact problem resolved, but please forgive me if I overlooked the answer, and I will appreciate if you point me in the right direction for the solution.

Thanks for any help you can give to point me in the right direction.

-Kevin

 

[Pradipio]

Hi @Anonymous ,

Thanks for posting to Fusion Forum...!

I appreciated your efforts, but I have a question what is the location of the pivot ball? is it in a fixed position?

The location is important because when we are trying to create a sweep of the lollipop cutter for groove the tilting direction will be defined from the particular location. and in this case, the location is a spere center. 

Please let me know if this is correct. 

[Anonymous]

Thanks for the comment.  I updated the structure to include joints so it is more obvious about the movement of the pieces.  Also, I explicitly created the cam wheel and show how I want the groove to be cut into the cam.

To clarify your question, the pendulum pivots along one axis.  The cam wheel should rotate around an axis perpendicular to the pendulum axis.  I want to be able to create a groove in the cam wheel to drive the pendulum along an arbitrary set of angles.

Sketch 1 inclues the arbitrary spline path that I want the top of the pendulum to traverse. 

I projected the arbitrary spline path onto a toroidal surface (see Sketch 😎 since that is the surface that includes the possible positions of the top of the pendulum.

I tried several version of sweeps to generate this groove.  

1.  "I think this is it but won't finish the sweep" is what I think I want, but somehow it won't compute the sweep across my complete path from Sketch8.

2.  "Surface - not it (6)"  This sweep in the surface mode is too skinny in some areas, not leaving enough room for the pendulum arm.

3.  "Surface - not it 2 (7)" This sweep in surface toolset is also too skinny and seems to be really wild shaped.

4. "Solid - not it" Also is too skinny in some regions.

Here is a clip of the Bodies created by these test sweeps.

Here is a screen shot of the structure showing the pendulum pivot holder (turquise) and cam wheel (greenish and partly transparent) shown.  For the groove in the cam wheel that you can see, I have cut it out using the body "I think this is it but won't finish the sweep".  As you can see, the sweep did not compute across the complete path, so it is only created a portion of the cam profile, not the full profile that is desired.

Perhaps the core of my problem is "Not able to compute a complete sweep for this profile".  I appreciate any help you can provide.