Models

Below are three different models of the Kassel Hand that vary in design proximity to the historical artifact. The “Lookalike” most closely resembles the artifact’s appearance internally and the “Work-Alike” is modified to allow its plastic material to function more like the wrought iron of the original artifact. Finally, the “Work-Alike-Handle,” which adds a handle to the top shell of Work-Alike, is what our team used for key personnel and study participants without limb loss to interact with the model.

As every model has some modification from the historical artifact, these are not exact replicas. For starters, the original artifact was made of iron, not plastic! In thinking about the models’ relationship to the artifact, there are two things to keep in mind. First, as the artifact’s thumb mechanism is broken and some of its parts hidden from view, the model incorporates historically-grounded hypotheses about their shapes and interface. Second, our team made minor modifications to what we can see and know about the artifact to enable inexpensive, printed PLA material to move and perform closer to the durable metal of the original Kassel Hand. If you look through our digital 3D models of Lookalike and Work-Alike, we’ve noted items such as thickened shell walls, ribs, and even fillets that spread out loading and stiffen components to make operable plastic versions of the artifact’s iron mechanisms possible. The models bring to life the mechanisms of the Kassel Hand in a historically-grounded design that lets anyone with access to a 3D printer investigate how this prosthesis worked.