Hi,
how does a hydraulic/air auto closing chuck...??

i am not talking about a collet system i am talking about a 3 jaw auto closing chuck......

i know about a drawbar and how the collet system works but i dont know how to get the drawbar (that is pulling/pushing parallel to the spindle) to transfer the gripping power perpendicular to the spindle and still have enough power to hold the item in the chuck....

Thanks
Mike