This is a wind up mechanism that I designed to be fully 3d printed with no additional materials required and to be compatible with Lego. This opens up loads of possibilities for new exciting builds (Hopefully by people who are much better at Lego than me!)

This instructable will walk through the printing of and putting together of the winding Mechanism only

Supplies

PLA (Tested) Alternatively PETG or ABS, however I have not tested this with those.

3D Printer (I use an Ender 3, but pretty much any should do)

Lego, Lots of Lego

Step 1: Print the Mechanism

First off, head over to the download page on Thingiverse and download the files

Wind up Mechanism for Lego by Erykgecko

The download will include 3 parts, The Gear, The Ratchet and the Coil Spring. All 3 can be printed as is without the need for any supports. Depending on the direction you want the gear to spin on, you may want to mirror the gear and ratchet to make it easier to wind up, however, in testing, I actually found it doesn't matter which way the gear is printed, the ratchet will still work even if its facing backwards.

Tested Print Settings:

Material: PLA
Resolution: 0.2
Supports: None Required
Infill: 5%

I printed mine using rafts, but that shouldn't be necessary. Once printed, peel the parts off and you are ready to assemble

Step 2: Start With the Gear

Grab the gear. This is what will be providing the output for whatever you build. Its the same size as a standard 40 tooth gear. Add an axel through the hole, this will partly insert into the ratchet also.

Step 3: Add the Ratchet

The ratchet should sit nicely inside the gear and be able to rotate on the axel that we added in the previous step. Ensure that the ratchet sits flush inside the gear. The spiral direction is important, if you want an anticlockwise output, then the spiral should be Clockwise.

The ratchet is designed to allow you to hold the gear and wind up the spring in multiple turns, without it releasing, as you wind the spring, you should get a nice clicking sound, this is the teeth of the ratchet sliding over the inner teeth of the gear and then locking.

Step 4: Add the Coil Spring

Finally, you need to add the coil spring. This simply fits over the square peg of the ratchet. It is important to ensure that this faces the right way. The spiral of the spring, should match the direction of the spiral of the ratchet. Finally, add another axel into the top of the ratchet, and a standard Lego pin into the other hole on the coil spring which will hold the spring in place.

The mechanism is now assembled and ready to be used in a Lego build

Step 5: Build Some Lego

You're now ready to build some Lego. I'll leave this part to you. However, you will want to ensure you Gear up your build in some way as otherwise you'll get a quick and powerful burst of energy rather than a slow release.

I use a rounded gear as a winding Key as it fits easily on the axel

I hope this has inspired some of you. Please let me know if you come up with any brilliant wind up lego builds