The violin bow hand prosthetic was designed for a young violin player seeking to upgrade the functionality of his current violin prosthetic device. His current device is rigid, forcing him to play mostly with his shoulder. Since the strength of his wrist was unknown, we designed a prosthetic with enough brace flexibility to enable the user to control the bow motion with his own wrist. We also added an axis of rotation and spring mechanism to supplement this motion and provide him the equivalence of fine finger adjustments. The full design process of the prosthetic is documented in this report, including initial research, proof of concept models, calculations, two rounds of prototypes, CAD drawings, and design refinement analysis. The entire assembly cost $ 52.88, excluding freely provided 3D-printing services and tools. The final prototype is made of a brace, four 3D-Printed parts, some fasteners, and some springs. Of the 3D-Printed parts, the first connects to the brace and the second part pivots about the first via a shoulder bolt. The rotation is constrained to 30 degrees (either direction) by some internal stoppers, and controlled by Coulomb damping and four springs which seek to bring the part pack to a straight equilibrium position. The third and fourth 3D-Printed parts are caps to the slots which hold the bow. These are fastened with bolt inserts and wing nuts, and are shaped in such a way as to minimize damage to the bow when it is gripped.
Mechanical Engineering Design Project (MEMS 411)
Smith, Jonathan; Azziz, Jonathon; and Pavey, Shawn, "Violin Bow-Hand Prosthetic" (2019). Mechanical Engineering Design Project Class. 119.