Worm Gear Assembly Not Interacting

twharvey

I think I've missed something fundamental. I've built a model of wooden worm gear assembly. The worm has an attached motor and the worm gear has a hinge. Both of them turn on the correct axes and the worm works with the motor correctly. However, when I run the simulation, the worm passes through the gear teeth as if they weren't there. The two joints are connected gear-to-gear.

I'd appreciate any help I can get.
Tom

mptak

Nice design. I think the screw needs to be assembled by a bunch of small incremental inits made up of convexhulls and then bound to the base crank cylinder.

twharvey

Thanks, MPTAK,

I'll give that a try this afternoon. I've already done this with the gear after reading this: http://support.ponoko.com/entries/21249896-Gears-and-Joints-with-SketchUp-Sketchy-Physics.

I can't take credit for the design, I'm afraid. I saw this photo on Wikipedia:
http://en.wikipedia.org/wiki/File:CNAM-IMG_0602.jpg

Tom

twharvey

WoodGear1c.skpOK, I've made both the worm and gear into collections of individual components each of which is configured as "convexhull". When I run the simulation, they now seem to interact but not as gears. The worm shaft turns as expected, but the gear just nudges down a fraction and doesn't turn on its axis.

By the way, here's a picture of the original and the model:

And here's the model as it stands now:WoodGear1c.skp

twharvey

I finally got it working properly. If anybody is interested, I can provide details.

WoodGear1d.skp

mptak

Cool beans! I'm glad to see that others are struggling with all this and sticking with Sketchy Physics.

I'm by far not an expert but have picked up a thing or two. Your model looks great but I fear that the base cylinder around which your screw is attached may not be being read as a cylinder. It tends to cease a bit on me and I would guess that the large wheel is correctly modeled. Once I get it spinning I'll try to do some of the movie capture I have been playing with and share it back to you. Mr. K provides a great script to enable good capture.

twharvey

@mptak said:

Cool beans! I'm glad to see that others are struggling with all this and sticking with Sketchy Physics.

I'm by far not an expert but have picked up a thing or two. Your model looks great but I fear that the base cylinder around which your screw is attached may not be being read as a cylinder. It tends to cease a bit on me and I would guess that the large wheel is correctly modeled. Once I get it spinning I'll try to do some of the movie capture I have been playing with and share it back to you. Mr. K provides a great script to enable good capture.

I'll look forward to it!!