How do you calculate the gear tooth ratio of a virtual for bar?

De modo simples e direto como calcular a relação de dentes das engrenagens de um virtual for bar?

Are you trying to keep the ends parallel? If so, then you use the same number of teeth on each side.

But, if you want one end to turn relative to parallel, then you need to know (a) the angle at which the arm will sweep through, and (b) the angle at which you want the far end to sweep through.

Let’s say that (a) is 45 degrees and (b) is 90 degrees. In other words, at the bottom of the swing, the other end should be vertical, but it should be horizontal at the top.

And, let’s say that you have a 100 tooth sprocket at (a). When you draw that through 45 degrees (1/8th of a circle), it will pull through 1/8th of those 100 teeth, or 12.5 teeth. You need a gear at the other end which will go through 90 degrees (1/4 of a circle) using those same 12.5 teeth. 12.5 * 4 = 50. So, you’d need a 50 tooth sprocket.

The ratio then is (a)/(b), where (a) is the angle at which the arm will move relative to piece mounted at one end, and (b) is the angle at which the arm will move relative to the piece mounted at the other end.