Chuck adaptor for machining wyes - GIF

[nova_robotics]

Can anyone explain to me how those jaws are driven. Is there a drawbar that is powered?

I know of a couple, but there are probably lots of different designs. I have a machine that hydraulically pulls a collet into the chuck. It doesn't move very much, maybe 1-2 mm, but it's enough to get it to grip the workpiece. Then there are others that inject fluid into the chuck body to close the jaws. I think some might act on the jaws directly, but the (admittedly very few) that I've seen have pushed (or pulled?) on a wedge plate, and I've seen videos of ones that drive a scroll plate in the chuck. I think the video above might be a scroll plate because it has tons of jaw travel, but that's just speculation. You can get pneumatic retrofits for manual lathes an AliExpress for about half a kilobuck. They have a stationary collar and you connect air lines to the collar. It would probably be a great addition for a production machine.

Edit: Here's a video of a really cool design that I just found on Youtube. This is new to me, but it looks neat so I'm posting it.