Three-Dimensional Computer-Aided Design Reconstruction and Finite Element Method Analysis of the Complex Inner Mechanics of the Second Iron Hand of Franconian Imperial Knight Götz von Berlichingen

Background/Objectives: The subject of this work is the reconstruction of the inner mechanics of Götz von Berlichingen’s second iron hand. The complex inner mechanics were unknown until Christian von Mechel published a detailed description in 1815. In this artificial hand, each finger can be engaged individually in its three joints and the thumb in one joint. Methods: Based on this description, the individual components were reconstructed at an enlarged scale of 2:1 using computer-aided design (CAD) software and a three-dimensional (3D) printer for the mechanisms. In addition, a finite element method (FEM) analysis was carried out for the components exposed to the greatest stress in order to identify critical areas. Results: By making some adjustments to the mechanics, it was possible to reproduce the mechanisms on a scale of 2:1 on the basis of the index finger. However, when the model was rescaled to 1:1, the internal plastic components were too fragile. This problem was caused by the properties of the 3D printing materials and could be solved by manufacturing the springs from steel. Conclusions: This work aims to make a valuable contribution to the preservation and understanding of the historical artificial second iron hand of Götz von Berlichingen. It once again demonstrates the very precise and detailed craftsmanship of goldsmiths of that time.