In one example, an arm assembly with an arm locking system is described that can include a base to position the arm on a support structure, an extension arm having first and second ends, the first end of the extension arm connected to the support structure or base at a first joint proximate the first end. The system can include a lift arm having third and fourth ends, the third end connected to the extension arm at a second joint proximate the third end, the fourth end being height adjustable relative to the base. The system can include a first lock engageable to selectively prevent movement about the first joint, a second lock engageable to selectively prevent movement about the second joint, and a third lock engageable to selectively prevent a height of the fourth end from being adjusted relative to the base or extension arm.