For some time now I have been a member of the e-Nable France association.
e-Nable is a community of volunteers that develops assistive technologies such as 3D printed hands. These hands are offered free of charge to children with agenesis (born without fingers).
I am currently working on a prosthesis project that would allow children with agenesis to ski.
To ensure that the ski pole is attached to the prosthesis, I modelled a wheel clamping system.
This is the system I am presenting to you. I didn't invent anything but after searching in vain for a solution on sites offering printable 3D files, I didn't find anything adaptable according to my requirements.
The principle is simple, you turn the knob clockwise and the coil inside winds the cord. The pawls hold the coil and prevent it from rotating in the opposite direction.
To loosen the cord, simply pull the knob and the coil will be released.
You can adapt this device to your own needs. It is only a first draft that is being improved but is working very well.
I used PLA and a 4mm nozzle.
This system consists of a mechanical system with low tolerances. I therefore recommend printing all parts with a layer height of 0.1mm.
For the ratchet part I added a stl file with a support offset by 0.3mm to facilitate printing (to be printed without additional support).
The two parts to be glued are the circular spring inside the knob and the pattern on the top of the knob that you can print in the color of your choice.
The pawl is inserted into the circular spring by means of the three tabs.
The spacer must be inserted between the ratchet disc and the circular spring.
The corp_2 part for fixing with M3 screws.
The piece corp_3 for sewing fixation.
Use a 20mm M3 screw and an M3 hexagonal nut to close it all.
For the cord follow the attached pictures.
Before final assembly, check that the spacer on the spring and ratchet disc is sliding correctly.
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