TENSIONING MECHANISMS FOR ARTICULATING SURGICAL INSTRUMENTS SUCH AS FOR USE IN ROBOTIC SURGICAL SYSTEMS

An articulation assembly for a robotic surgical instrument includes a plurality of rotatable but longitudinally fixed lead screws extending between first and second base plates, a collar threaded about each lead screws and configured to translate therealong in response to rotation of the corresponding lead screw, an articulation cable coupled to each collar and defining or having a threaded shaft, and a threaded nipple threaded about each of the threaded shafts. Each threaded nipple is engaged with one of the collars to thereby engage each of the articulation cables with a corresponding one of the collars such that longitudinal translation of the corresponding collar pushes or pulls the corresponding articulation cable. Each threaded nipple is configured for further threading or unthreading about the corresponding threaded shaft to vary a pre-tension on the corresponding articulation cable.