GearHeads Corner

I'm a novice at gears so bear with me.  I have attached a link to a fixture I would like to make something similar.  They give some ratios but don't explain what they are referencing.

could someone enlighten me?

I assume R1 and R2 reference the radius of the orange and yellow gears respectively.  that R3 and R4 reference the radius of the blue and green arms (what are these correctly called?).


http://mechanisms.club/video/self_centering_fixture_4/

can this be modeled in Gearotic?

Hi:

Think of the arms as gears..mentally stretch them out to full circles on their racks..which
are really just chords of gears with the green being a planetary gear and the blue just an ordinary
gear.

You can make them in gearotic, in terms of getting the ratios right , but you cant really simulate them.
Soon, you'll be able to get the gear data from gearotic into the new cad program, draw the arms and trim the gears to be what you see in your example and send them back to gearotic so they look like that, but it wont simulate them even then, though that will make it easier to make such a thing.

Art