The rotating shaft is the joint that lets a midline joystick swing out of the way and come back to exactly the same driving position. It locks at set points, so your client finds the controller where they expect it every time.
That repeatability matters for driving accuracy, and so does stiffness: movement at the end of a long arm costs the client precision, and this shaft is compact and high strength to keep it out of the system. Hidden flip-stops switch between independent release, where the client moves the arm themselves, and assisted release, where a carer does it.
The set positions cover driving, transfers and table access, so getting to a table or out of the chair does not mean taking the mount off.
