Ratchet Hand

  • The Ratchet Hand is a DIY prosthetic. Based on the open source RoboHand, we used that structure and reinvented our own hand. The Ratchet Hand uses the ratchet mechanism so that the wheel can offer multiple utensil holders. The hand offers an amputee to use a pencil, paintbrush, sharpie, fork/spoon, and knife. This allows one to use multiple utensils for various purposes from eating to drawing.

  • To preface what we did I would like to start by saying that Catherine and I are both musicians. I am a classically trained violinist , and she is a concert pianist; and thus we could not imagine our lives without the use of our hands which in turn provide us with creative outlets but furthermore provides us with motivation to equipt others who do not have our privelages with a means of self expression. 

    In this studio, our goal was to expound upon the functionality of the Robohand( the original 3d printed hand) by making it more utilitarian, friendly, and durable. The results were the dawn of the "Ratchet Hand,". An important aspect we wanted to focus on was aesthetics. For children especially, we found that art is crucial means of self expression. We thought that certainly everyone should have the ability of self expression, and having no hands should not be a limiting factor. 

    The main structure of our Ratchet Hand is based off of the RoboHand. The RoboHand is inexpensive and available in .stl form worldwide. In our project, we focused on reinventing the fingers and knuckle board. To begin the design process, we started off creating a bridge that would hold artistic utensils of specific circumferences. We found out this was really inconvenient and bulky. So, we changed it into a spherical shape. This allowed for more flexibility and created more of a curved and smooth surface. After our first 3-D prototype, we found that the sphere was very bulky; as a way to keep a smooth shape, we went to a cylinder shape with lofted edges. This way, it wouldn't be as bulky but still maintain a nice surface. One major component of our hand is the ratchet mechanism. The ratchet allows the cylinder to move and give multiple positions for the person to use the utensils from. It also holds the position in place.

    We changed the design from strictly art "instruments" but to general utensils. To fit the utensils, we were going to use a threaded screw concept so that way any circumference pencil, pen, or marker could fit. Unfortunately, we were unable to complete this idea. In the end, we had specific circumferences for different utensils. Our final Ratchet Hand can hold a pencil, sharpie, paintbrush, fork, and knife. It is multifunctional and universal for many to use.

    We are developing a couple new interchangeable ratchets, that are more germain to the task in which they will be used: a ratchet cylinder for eating utensils (solely), a ratchet hand for writing(different circumferences). Also one that has a pencil sharpener and maybe even a lazer!

    Thank you to team ratchet, and everyone at nuvu for inspiring us to do what could not be done.