Christian von Mechel’s Reconstructive Drawings of the Second “Iron Hand” of Franconian Knight Gottfried (Götz) von Berlichingen (1480–1562)

In our recent review [...]

In our recent review [1], we outlined the 3-dimensional (3D) computer-aided design (CAD) reconstructions of the first "Iron Hand" of German knight Götz von Berlichingen (1480-1562), a historical hand prosthesis of the Renaissance replacing the knight's right hand, which he, at the age of 24, had lost during the Landshut War of Succession due to a cannon ball splinter injury in 1504 [2,3].
In this piece, we focus on the second "Iron Hand". The hand prosthesis was built around 1530 by an unknown armorer, probably from the Franconian region, and still can be viewed in a glass showcase in the Castle Museum of Jagsthausen, Germany.
In 1815, the Basel-born engraver Christian von Mechel (1737-1817) illustrated and described the second "Iron Hand" and its elaborate mechanics in a short book of 10 pages that includes two detailed copper etchings (Figures 1 and 2) of the hand prosthesis at a scale of 1:1 (they are called Tabula I and Tabula II in the book) [4]. Mechel was given permission by the von Berlichingen family to dismantle the hand for this purpose.
In illustration 5 (with extended finger) and illustration 6 (with flexed finger) of Tabula II (see the two drawings on the lower left in Figure 2), the mechanism of the fingers is shown: after actuation of a locking lever in the chassis, a chain reaction is triggered in which an oblique hook jumps out of its opening by shooting up the proximal phalanx, thus releasing the locking of the medial phalanx; the medial phalanx then also jumps up and, by ejecting its oblique hook, in turn releases the locking of the distal phalanx ( Figure 3).
In 1982, Günter Quasigroch was the second to inspect the original second "Iron Hand" [5], but this time he was not allowed to disassemble it. He noted that the overall mechanics were slightly coarser than those seen in Mechels' drawings. Quasigroch tested the functionality of this prosthesis in various everyday situations. The prosthesis did not seem very robust for heavy loads-the grip of the prosthesis was quite weak and loose, which probably did not allow the knight to wield a sword or a lance with this hand, since the mechanically very weak locking mechanism of the wrist did not allow this. In contrast, playing cards could be held effortlessly, and an attempt to write with a quill pen made from a swan feather was successful at first attempt.
Many designs and mechanisms of artificial hand prostheses still resemble those of the second "Iron Hand" of Götz von Berlichingen. Without the meticulous reconstruction of the copper engraver Christian von Mechel, this would probably not have been possible.    Götz von Berlichingen´s second "Iron Hand", external hand and forend: two-piece, round, slightly conical bracer (forend) for attaching the prosthesis to the forearm. Hinged flap closed with two leather straps and buckles. Four individual fingers movable in three joints, thumb movable in only one joint (the base joint of the thumb is firmly connected to the body of the hand). Two buttons were used to return the thumb or the four remaining fingers to the normal position (open hand) by spring force.