A recent addition to the line of 3D printed wheelchairs, the Hand Drive, has just been launched by two ingenious students. Kate Reed and Nathaniel Tong have joined forces to invent the Hand Drive, after they were challenged to improve wheelchair structure and make chairs more easy to use. Through extensive research, they discovered that the best forward motion for the wheelchair is achieved by a level-powered propulsion approach, which usually costs between around $2,000-$10,000 to make. However, Reed and Tong have managed to solve this expensive problem through 3D printing, by designing and manufacturing a level-powered attachment to go on the wheelchair.
This attachment only costs $40 to produce and and it allows any wheelchair to achieve forward motion through a level-powered rowing movement. This is a means of locomotion which has been proved to be much better for the back of the wheelchair-user. The difference in price is huge-- in fact only 1% of the cost, and which should make a big difference to the often under-served and disadvantaged disabled community. The newly-designed attachment is not only affordable, but the two students have also created the Hand Drive as an open source project, which means that anyone who has access to a 3D printer can both obtain and modify it.
So far, Reed and Tong have developed five major prototypes, and although they have achieved high levels of functionality with these, they are still working on improving their design. One of the first designs featured a dual-ratchet mechanism as an experiment, which works by springing the chair forward or backward, depending on which ratchet the user engages. Following the addition of three double-sided ratchets onto one of the prototypes, the designers then decided to add a planetary gear system. The gears are first milled and then are set with 3D printed planetary ratchets onto one functional unit, which propels the wheelchair forward when the clutch is engaged (this winds back the set of gears and ratchets, creating rapid forward motion). The gears are not yet 3D printed, but this is something the student designers are working on. They state in their project log that one of their goals is to have a design where the planetary gears can be 3D printed instead of milled, as they currently are, so that the Hand Drive can be made affordable and accessible to all.
The innovative project is being improved upon by the day and even as it stands it represents an opportunity for wheelchair users to have a low-cost and accessible modification which is open to all, which should be very beneficial to their mobility and overall well-being. This design can really set a precedent in terms of affordability for disabled people. What was once out of reach financially for so many, can now be printed in their own homes for a fraction of the cost.
Picture courtesy of www.3Dprintingindustry.com