# Cardan Gear

Invented by Girolamo Cardano in the 16th century the Cardan gear is a way of converting rotary motion into straight line motion. Watch how the red dot on the inner purple gear exactly follows the vertical dotted line. The outer gear has a diameter exactly twice as large as the inner gear. In the above example they have 40 and 20 teeth respectively. Cardano also invented a type of universal joint and investigated the mathematics of probability. Understanding the mathematics of risk helped him make a living from gambling until eventually he could find no-one to gamble with and had to move onto new pastures...

Anonymous (not verified)

some sort of answer to how it works would be nice too help me get on with school work but cool website

littlemisszombie

??????????? i do not understand your comment :/  because he  (rob) has said how it works???????

i am loving this, my little boy loves making models, and i'm so glad i've found this :D when i get paid (soon) i'm going to buy membership :D  when i was little i used to go to the village library, and constantly get out this book they had on automated toys and how to make them; it showed wooden toys, but i used to make them out of corrugated cardboard etc (hey it was the 80's :D) but this is brill!!!!!!!!! i just know that tomorrow, even if my little boy doesn't fully understand everything, he will just love the animation of it moving, and when i show him some of them with cereal box card etc he will be in his element....thanks for this site :D i can't get over it :D

robives

Thanks! I must admit I didn't understand the comment so I left it to answer later.

littlemisszombie

robives

Hi @littlemisszombie, yes the models on Flying Pig are printed models that arrive through the post.

Anonymous (not verified)

how does it work and could u put it in a toy

Anonymous (not verified)

What are the speeds in the end points of the linear motion contra the speed of the middle part?

The speed at the end points is zero, in the centre it is one, the speed varies between the extremities according to a sine curve. - RI

robives

It looks like the speeds will follow a sine wave. The end points will be speed zero with maximimum speed in the middle.

Katie Grace

hiya rob

great stuff!!!  what project would you say is a good example of this cardan gear mechanism?

thanks

Kt

The only place I've seen one in action was in a sewing machine raising and lowering te needle. - RI

umehta

Katie:

umehta

But to answer your question about what project may use this mechanism: 'Ornithopter' project uses cardan gear. Hopefully someday, Rob will design a paper ornithopter!

That would be a fun project! - RI