I've seen this linear actuator end effector on a few industrial SCARA 'bots but I am having trouble visualizing how it works internally:
It looks like a type of lead screw, but the nut must spin instead of the rod to cause motion. If this is the case would the end part of the effector not also spin with the rod? Does this end effector design have a specific name ? If you can explain how the mechanics of this joint works It would be very helpful.
All help appreciated.
Edit: Sorry for the low res picture, more detail about the type of joint im looking at can be found at:
Models that have this type of joint include the Epson T3