Flex Fingers: Design of a partial hand prosthesis

Flex Fingers: Design of a partial hand prosthesis

Stoop, E.M.

Jansen, A.J. (mentor)
Albayrak, A. (mentor)
Plettenburg, D.H. (mentor)

Industrial Design Engineering

Design Engineering

Master of Science Integrated Product Design, Master specialisation Medisign

2010-03-05

This master thesis describes the development of Flex Fingers, a prosthesis for people with a partial hand defect. People with a partial hand defect miss fingers and sometimes part of their hand, they do have a functioning wrist. There are already many types of prostheses on the market, but there is no suitable prosthesis for the target group. The existing prostheses were studied to determine which development direction was preferable. It was decided to develop a wrist driven prosthesis, because of the high amount of remaining and additional tactile feedback. People with a partial hand defect are not able to grasp all objects and perform certain tasks. To gain more insight in the types of grasp the users need most and objects they would like to grasp, patients, therapists and instrument makers were interviewed. The interviews led to the following project goals: 1. Offer a prosthesis for as much patients as possible with various personal preferences and types of defects. 2. Make the appearance of the prosthesis either natural or mechanical and preferably offer both options. 3. Cover as little of the stump as possible. 4. Improve the patients grasping possibilities as much as possible. 5. Sensory feedback of both stump and prosthesis should be as high as possible. First developmental step was the ideation. The ideas were evaluated on the project goals and by the patients, therapists and instrument makers. This led to the decision to go on with the idea of developing ‘low power fingers’. The ‘low power fingers’ were optimized using a morphological chart. Further development resulted in 2 concepts with differences in appearance and working principle. Both concepts were evaluated on project goals by a Harris-profile. ‘The finger alternative’; a bar-driven, non-human appearing design was chosen. This design was optimized into a final producable product. The most important innovation in this phase was the application of Rapid Manufacturing for the production of the fingers. This is a promising technique for prosthetic production, where low batch sizes are common. A prototype was build and was tested by a person with a partial hand defect. The user-test showed the pinch force is around 40% of the pinch force of the human hand. Some adaptations can be made to improve comfort. The final design functioned properly during the test and offers added value to the lifes of people with a partial hand defect.

design
prosthesis
prosthetic
partial hand

http://resolver.tudelft.nl/uuid:a01b1a37-a9fd-457d-8527-718ea7d7cdb2

Campus only

Student theses

master thesis

(c) 2010 Stoop, E.M.