Preloaded Surgical Instrument Interface for Zero-Backlash Torque Transfer

The patent applies preliminary action by pre-loading the mechanical interface with springs before operation. The preload force is applied in advance to eliminate backlash between mating surfaces, ensuring that when torque is transmitted during surgical procedures, there is no play or unpredictability in the motion. This pre-compression of the mechanical interface maintains zero backlash throughout operation.

The patent employs asymmetry in the alignment elements where the drive output disk has protrusions that correspond to recesses in the intermediate disk. This asymmetric geometry provides self-alignment and precise coupling without requiring additional alignment features. The asymmetric shapes guide the disks into proper orientation automatically during assembly, achieving high alignment precision with minimal added complexity.

The patent segments the assembly process into two distinct phases: first, the disks are brought together and engaged using minimal force to establish mechanical contact; second, the preload springs are compressed to apply the elimination force that removes backlash. This segmentation allows the high force to be applied only during the preload phase, not during initial assembly, thereby reducing the overall assembly force requirement while still achieving backlash elimination.