Patent | Locking SwingArm

This patent covers a self-engaging swingArm. The swingArm bridges a large tolerance gap between gear drives of two major assemblies by using a freely pivoting idler. This is an extremely low cost solution for a high-precision gear train, using the gear reaction forces themselves to retain the drive without the need for extraneous parts.

Although a basic swingarm is nothing new, the innovation in this patent is the configuration of the gears and retaining features to make it self-engaging in both drive directions. The predecessor design had an issue of the swingArm being ejected under high loads and reversals.

I plotted several different gear geometries and their reaction vectors and determined a configuration that would pull the linkage into engagement in the high-load direction. For the low-load direction I utilized a track to guide a hook upward such that the gear reactions were over-center and could not be forced out. Only manually extracting the assembly would the swingArm disengage for servicing.

Other design details in this mechanism included ease of assembly using custom snap rings, minimizing friction by using grease grooves and debris ejection, and preventing warpage by optimizing ribs and materials.