Tabletop Pull Back Tri-Mode Spring Motor Rolling Chassis is a fully 3D printed rolling chassis having 3 modes of operation, wind, power and coast.

My earlier 3D printed windup vehicles used a key or knob to wind the spring. This vehicle uses a floating pinion gear designed to wind the spring when the the vehicle is rapidly rolled backwards. This is the wind mode.

Once the spring is wound, releasing the vehicle propels it forward until the spring is depleted of its stored energy. This is the power mode.

Finally, after the spring is depleted, a second floating pinion gear disengages the spring motor from the rear axle allowing the vehicle to coast. This is the coast mode.

This vehicle does not outperform my earlier designs for distance, but it does illustrate that there's always room for improvement!

I probably forgot a file or two or something, so if you have any questions, please feel free to ask.

Designed using Autodesk Fusion 360, sliced using Cura 2.3.1, and printed in PLA on an Ultimaker 3 Extended.

Step 1: Print, Prepare and Purchase All the Parts.

You will need to purchase 12 "AS 568" size 221 (1 11/16 O.D., 1 7/16 I.D., 1/8" section) o-rings for the tires.

I printed my parts on an Ultimaker 3 Extended using .1mm vertical resolution and 100% infill for "Axle Spring.stl", "Spring.stl", "Gear Spring.stl" and "Axle Rear.stl", the remaining parts at 20% infill.

Prior to assembly, test fit and trim, file, sand, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on the colors you chose and your printer settings, more or less trimming, filing and/or sanding may be required. Carefully file all edges that contacted the build plate to make absolutely sure that all build plate "ooze" is removed and that all edges are smooth. I used a flat jewelers file and plenty of patience to perform this step.

Study "Assembly.stl", carefully noting the locations and positions of the various components as assembly proceeds.

<p>Greg, love your design work and sense of style. This one has been added to my long list of projects to try. I went looking for the o-rings on the chinese sites where I get a lot of my components and they don't sell AS 568 size 221 o-rings, everything is in metric. After a little research this is what I found, perhaps it could help others looking for the part. </p><p>From what I could tell the 221s have an inner diameter of 36mm so as long as you are somewhere around there you should be good, right? I ordered the 44mm(OD) x 36mm(ID) x 4mm(CS), I was able to get 20 of them for about $5. I suspect the 40 x 36 x 2 would also work</p><p>Also you may want to change your description of your o-rings, I think you have the ID and OD reversed.</p><p>Thank you for sharing</p>
Hi Christyl,<br><br>Thank you very much and I am glad you enjoy my tinkering!<br><br>I purchased this kit of o-rings: https://www.amazon.com/gp/product/B000OMKIDI/ref=oh_aui_detailpage_o00_s00?ie=UTF8&amp;psc=1. I've bought quite a few of these kits in both metric and standard.<br><br>I've know people who have tried size 220 through 222 and they all fit well, though the 220 did fit tight. Yours should work great.<br><br>And many thanks for the correction on the diameters (that would make for an interesting o-ring). I depend on people to keep me in line, and thanks to you I believe I've got this one correct now.<br><br>Thanks again!<br><br>Greg
<p>One more question, I printed the front and back wheels, in the picture they look about the same height but the front wheels printed significantly smaller. 50mm vs 40mm all the recommended o-rings are the same size. I'm a little confused please enlighten me.</p><p>thanks</p>
<p>Well that is indeed curious. As designed, they are all be the same diameter (40mm). The rear wheels are wider (e.g. 4 o-rings as opposed to 2) for traction. I'll check the files again when I get back to the computer.</p><p>I'm very sorry for the difficulties you've encountered with this model.</p>
<p>Great project.Thank you!</p>
Thank you so very much, I'm glad you enjoyed it!
<p>Nice design. I like that they can see how the gears work. I'd like to do the wheels differently. Have you made the fusion 360 files available somewhere?</p>
Thank you so much and I'm glad you like it!<br><br>I'm very new to both Instructables and Autodesk Fusion 360, and have yet progressed to the point where I know how to post the files. I'll read up on that and try as soon as possible to post the wheel files.<br><br>Thanks again!
<p>what a great little build. thanks. I had trouble with pango as a slicer, dealing with the hook in the spring gear. cura handled it easily and it printed easily too. printed with my Trinus3d.really clean neat project with good fits and clearances . </p><p>really clw</p>
<p>Great job, congratulations!</p><p>Thanks for posting your work!</p>
<p>loos to be a couple parts missing. the axle for the idler, and the front axle? can you clarify??</p>
<p>ive got it 1/2 printed, might have to cad up the parts myself?</p>
<p>I also cant seem to make this pretend its solid.. it prints with this tube missing on part gear spring. was there a way you overcame this? hope you can help.</p>
<p>The spring retaining hole wall in &quot;Gear Spring.stl&quot; is .8mm thick. If your printer does not print well (or at all) at that thickness, I've uploaded &quot;Gear Spring New.stl&quot; that is 1.2mm thick which hopefully will work for you. I have not tested it so let me know how it works out.</p>
<p>thanks, ill try that.. :) excited to finish this. so far a nice design! ill keep you posted!</p>
<p>I hope it works for you. You could help me a lot if you could tell me the minimum wall thickness your printer can successfully print. With that information, my future designs will utilize your input so that I can avoid mistakes such as this in the future.</p><p>Many thanks, and thanks again for your input, and I am anxious to see your print!</p>
Thankyou.i think with some adjustment , now I know why it won't print, then I should be able to do it easily.
<p>Uploaded the files.</p><p>Sorry.</p>
Oh exciting! Thankyou
<p>Thanks for pointing that out, I've uploaded two files, &quot;Axle Front.stl&quot; and &quot;Axle Gear Idler Large.stl&quot;.</p><p>Sorry again for the problem.</p>
Thanks, glad you like it!
<p>great job! </p>
Thank you very much!

About This Instructable




Bio: Formally the owner of avionics (EFIS, FMS, etc.) and video game design (Tetris, Robocop, Predator, Michael Jordan in Flight, and a number of others) firms ... More »
More by gzumwalt:Single Cylinder Air Engine Balloon Powered Rolling Chassis Dual Mode Windup Car Pencil Puzzler Revisited 
Add instructable to: