An artificial substitute of missing finger
November 8, 2012 | Anonymous | 0 comments
This post is meant to outline the overall design and function of the prosthetic mechanisms so far developed by Richard Van As of South Africa in combination with Ivan Owen of the United States. All of the information and designcontained in this write-up is open and available to the public to be used freely.
The intended application of the mechanical designs described below is to provide increased functionality to the hands of individuals who are missing all or portions of their digits. This increased functionality is achieved via the application these core elements:
- Formed rigid or semi-rigid material in combination with flexible materials worn on the remaining potion of the hands and fingers to provide a base with which to mount the artificial digits
- Lever arms and hinges to achieve articulation of the artificial digits
- Cables, pulleys and levers to provide power and driving force to the artificial digits
- Passive tension systems (in the form of bungees or springs) to return the digits to a neutral position once the amputee is no longer providing driving force to the digit.
Some of the ideas for these devices fall under the category of prior art as they came from a prosthesis constructed in 1836 by an Australian dentist named Robert Norman. As the device in question is well over 100 years old, the methods used in its creation fall under public domain and can be used freely.
Prosthesis one:
System utilizing formed hand-mount, cables, pulleys and levers.
System utilizing formed hand-mount, cables, pulleys and levers.
Description of construction:
The hand mount (A) is made from rigid material and formed to the amputee's hand. The lever arm (D) is attached to the hand mount with an axle at position (I). The passive tension system is attached to the hand at position (F)
The artificial finger is made up of a rigid lever arm (D) to which pulleys (C), a form fitting sleeve (B), hinge (E) and Finger tip with grip pad (G) are attached. A cable runs from the finger tip (G) through the pulleys and attaches to the hand mount at position (H).
The artificial finger is made up of a rigid lever arm (D) to which pulleys (C), a form fitting sleeve (B), hinge (E) and Finger tip with grip pad (G) are attached. A cable runs from the finger tip (G) through the pulleys and attaches to the hand mount at position (H).
Description of Motion:
When force is applied by the amputee to position (B), the lever arm moves downward, rotating around axle (I) and raising the lever arm at position (D). This increases the distance between positions (D) and (H), thus pulling the cable and resulting in the hinge at position (E) bending. When the amputee releases pressure an raises their stump, the passive tension system anchored at position (F) pulls the hinge (E) back into a neutral alignment.
The same motion described above from a palm view:
To read more about, or donate to this project, please visit the project's blog: http://comingupshorthanded.com/
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