Folding pedal for bicycle
Folding pedal for bicycle
3D
Published 2017-10-26T09:37:52+00:00
Back in 2016, I broke the pedal on my folding bike. Yep, it was a folding pedal, and I could not find another one online to buy a replacement. So design one.
Well, the metal shaft was still OK, so it was only the plastic stuff that had disintegrated and I lost the spring in it.
Easy enough: just copy the other pedal, well, sort of.
The pedal needs a spring (about 9-10mm OD by about 50mm long), to keep it locked in position when pedalling. I did create a plastic spring, but it really did not have the strength to be 100% reliable and was really hard to print using a filament machine. It might well be much better in another material, like the plastic used in Sinterit Lisa.
The original design has 2 of 30mm long by 3mm diameter bolts, to lock in the bearing block into the frame. Slide the bearing block into the frame before putting in the bolts.
Now, if I was designing just for the Sinterit Lisa, I'd remove the bolts (and the holes), add two locking blocks to the bearing block where the bolts go, and print the frame and the bearing block in position (similar to what is in bike-pedal-all.stl). If anyone wants this design, add a comment, and I'll put in the effort to create it. However, I see little demand for this rather unique object, and most people are likely to only have access to filament printers anyway, so I'll put off doing anything more until requested.
The bike-pedal-all.stl has both major parts and it will just fit into the competition specifications for Sinterit Lisa laying down.
I am not sure of the clearances needed to ensure movement on Sinterit Lisa, but putting in the pedal-spring-cylnder is probably workable too. Because the spring needs to be under compression, it cannot be printed inside the housing! I suspect (but am unable to test) that printing a spring on Sinterit Lisa is quite practical: it does not need to be super strong, just strong enough to keep the pedal locked in place when being used.
This object was originally designed, and printed, on a filament printer. I chose ABS, but it could have been just as good in PLA. I did choose a good thick shell thickness of 1.6, but it could still be quite OK with less. I did also choose a higher than normal internal support at 40%, but that was because I could err on the high side without serious penalty (and I did not want it to break again in use). I chose the direction of printing to ensure that there were no overhangs requiring support (on its outer end).
| Date published | 26/10/2017 |
| Technology | FDM |
| Complexity | Easy |