Handy, a Bicycle Assistive Device by pbeyl

Last crawled date: 3 years, 4 months ago

This is an assistive device to help a person with a hand limb difference to cycle with more confidence and stability.
Disclaimer
This is not a medical device and is provided as is with no warranty of any kind. Usage of this design is completely at own risk and the provided without any warranty. It is provided "as is" without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the device is with you.
Overview
I made this for my son to allow him to ride with more confidence while mountain biking. The majority of the device is printed however I also make use of orthoplastic for safety and comfort.
The orthoplastic is a very interesting material which can be easily molded into shape using warm water and a hair dryer. Cycling will at times require a person to remove their hand from a handlebar to avoid serious injury.
The orthoplastic enables the user to clip their limb into the mold and secure in place but will allow the limb slip out under excessive force to prevent serious injury like broken bones. This part will be unique for every person and probably requires some experimenting with what will work well for the individual.
Parts required
1 x Handle Bar Clamp (handle bar clamp.stl)
1 x Hand Support (hand support.stl)
2 x M6 x 30mm Hex Socket Cap Bolts
3 x M6 Nuts
1 x M6 square nut (insert into the hand support)
4 x M3 x 6mm Countersunk bolts
4 x M3 Nylock nuts
1 x M6 lock washer
1 x 250mm x 200mm x 1.6mm Orthoplastic Sheet
Orthoplastic can be found at suppliers of occupational therapy products. In South Africa I have been able to source Rolyan Aquaplast from www.hitechtherapyonline.co.za
Alternatively work with your occupational therapist to get the cup made.
Printing
The Handle Bar Clamp needs to be strong, I am still experimenting with plastic type, wall thickness and infill but the following seems to offer adequate strength slicing with cura and printing in PLA.
Layer Height: 0.2mm
Infill Density: 30%
Infill Pattern: Triangles
Wall Count: 3
Print with support everywhere
Once printing is complete, clean out all support material using a small pliers and sharp utility knife.
Assembly
Use boiling water to mold the orthoplastic hand cup.
Use boiling water to soften the hand support and mold to the shape of the hand.
Insert the M6 square nut into the hand support.
Mount the orthoplastic cup to the support using a M3 drill to make holes and fasten with the M3 bolts and nuts.
Insert the M6 bolt into the ball and fasten with M6 nut, ensure the nut is fitted in the space provided inside the ball.
Screw another M6 nut onto the bolt and then the M6 lock washer.
Screw the M6 bolt into the bottom of the hand support assemble to mate with the square nut and tighten with a wrench.
Add the other M6 Bolt and Nut to the clamp c section.
That completes assembly of the device, now remove the handle bar grip from the bicycle and mount the clamp onto the handlebar.
I included the fusion 360 design file should you wish to modify or make any improvements to the design. Enjoy!