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

Let's see if I can describe it adequately.

The jaws slide radially in slots in the chuck body, that part is obvious. :)

Each jaw has an extension that protrudes back into the interior of the chuck and this extension has a tee shape with the head of the tee at an angle of about 30 degrees to the centerline of the chuck.

Inside the chuck, and able to slide axially, is a disc with three tee shaped slots that the jaw extensions fit into, naturally these slots are also at an angle to the centerline.

When the disc is moved axially by the drawbar it slides along the jaw extension and because the sliding parts are at an angle to the axial motion the jaws move radially.

I have a dismantled chucking on my office floor and will try to remember to take a picture.

thanks geof

a pic would be great

Thanks Mike

I have a picture but my computer is not cooperating and will not upload the file. I will try with a different one some time.

EDIT: Picture loaded