Library Guide Service the Library Power Off the Library Lock the Robot Lock the Thumbscrew-type Robot Lock (older version) Lock the Thumbscrew-type Robot Lock (older version) The older lock style has a lock assembly secured with a thumbscrew. Loosen the captive thumbscrew on the lock assembly. Pull the lock straight out until the long tab comes out of the slot at right. Rotate the lock assembly counterclockwise 180 degrees, and slide the long tab into the slot at left. Verify a red locked padlock icon is visible in the small window. Secure the lock assembly by tightening the captive screw. The robot is now locked.