Introduction: Flapping Bicycle Mascot, Fully 3d Printed
Runner Up in the
3D Printing Contest 2016
Ever felt inferior to all the Rolls-Royce owners in your neighbourhood, when getting on your rusty old bicycle for the way to the office? Work colleagues honking and jeering at you when passing you with their Bentleys or even a petty Mercedes Benz?
Well, there's an end to your suffering!
Pimp up your old bike with a stately mascot. Even better, a wind-wheel, concealed behind a classic chrome grille, drives the mascot, so when riding your bike it will start flapping its wings, turning the faces of all those luxury limo owners green with envy!
The Bicycle Mascot works just like a good old toy almost everybody had as a child: the "jumping jack" (or "Hampelmann" in german). A pullstring is used to lift the wings that will drop back due to their weight once the pullstring is released. To automate this process while riding your bike, I decided to use a wind wheel with a slightly off-center pin to which the pullstring is loosely connected. The relative wind drives the wind wheel (an idea I used before in my bicycle bubble machine) which will make the off-center pin periodically pull the string by approximately 1cm.
LEGAL NOTE: For the design files to this instructable, I've used the following open and free to use third party works: I generated the woman figure using the character creation tool “ManuelbastioniLAB” created by Manuel Bastioni (www.manuelbastioni.com); all output of this software is licensed under creative commons attribution license. For the wing version (instead of the arms seen in the video) I also used the design "Wings" by Matthew Krebs, licensed under creative commons attribution share alike license. My own work is also licensed under creative commons attribution share alike -- meaning you are not only free to use, but also to modify this, as long as you mention my work and make it share alike as well (see details here).
Step 1: Preparations and Printing
What you'll need
I think (and hope) this instructable qualifies as fully 3d printed, as you only have to add a screw, a hex nut and a pullstring.
So, you'll need:
- a 3D printer, obviously, or someone to print this for you
- an M3 cylinder head screw, 30mm, with nut
- some pullstring: like some twisted yarn or twine
Optional, but maybe a good idea:
- 2x M3 cylinder head screw, about 16mm, with nuts
- an M3 washer -- might make this run more smoothly if you encounter friction problems
As always, when making 3d printed mechanical stuff, you should be equipped with things like a sharp knife and files. Also, you'll need an allen key.
Check your bicycle first
My bike's handlebar has a diameter of 25mm on the middle part, where this machine connects. Please measure your handlebar first to see if this thing fits without modifications. If your diameter is a little smaller and you don't feel up to the task of modifying my design, you might want to just use some leather or cloth strips to get enough grip to the handlebar.
Now, print all the pieces. I tried to give all pieces enough clearance for this to run smoothly, but it will make your life easier if you have a well calibrated, good printer with a sufficient build volume (the grille/hood measures roughly 150x166x159mm -- I have ideas for a simple mount without a grille and with much less footprint, but that's for the future). Also, it's good to use a reliable printer -- thanks for helping finish this project go to my brother and his machine, as my DIY Kossel is so quirky and delicate I wouldn't ever let it run overnight ...
You'll need to print the following parts that you will find here.
- 1x hood.stl
- 1x windwheel.stl
- 1x mascotbody.stl
- 1x mascotarms.stl (work better right now than mascotwings.stl, into which I have to put more work ...)
- 2x mascotclip.stl
- 2x mountclip.stl (optional, needs two more screws and nuts)
Settings: In general, I like to use three shells at least, but very little infill (10%). However, for the mascot and the grille I used 40%: the mascot rests on a very small area and its head has only a small connection to the body; the grille has the mounting clips which have to take some strain.
For the wind wheel and the arms, you will have to use support. Be careful during removal, as parts may easily snap. The mascot body may print well on good printers without support, but I'd use it (it's much easier to remove than the support for wind wheel and arms). The rest of the parts don't need support.
Especially for the mascot body and the wings, printing with a raft is a good idea. The rest printed well without for me.
I decided to spray my printed parts silver, mainly because I didn't have any silver filament at hand.
Step 2: Assemble the Printed Parts
Assembly of the printed parts should be straight forward.
The wind wheel is mounted inside the hood using the 30mm M3 screw and a nut. You'll find a pocket on the inside of the grille where the M3 nut fits in. Hold the hood upside down and drop an M3 nut into this pocket. Put the the 30mm M3 screw through the hole in the wind wheel, with the head to the side of the pin on the wind wheel. The wheel must run absolutely freely on the M3 screw (it did right away with my brother's printer) -- if not, take a drill to remove any printing debris in there or widen the hole. It may be a good idea to put an M3 washer on the screw, between the wheel and the grille, to reduce friction; many washers have a smooth and a rough side, put the smooth side to the wheel. Now screw all this through the pocketed nut; the wheel should still run freely, if not, try loosening the screw a little again.
Now connect the mascot to the hood. You have two little flat clips to do this. They're a tight fit because they're supposed to hold: first push them through the holes in the mascot's stand, then through the corresponding holes in the hood.
Step 3: Connect the Pullstring
Well, this is the most finnicky part of it. On the arms or wings you have a slot where later you will place them on the shoulder shafts of the mascot. And you have a hole where the pullstring should go through. When mounted, the holes in both arms will be adjacent to each other. Place the arms in front of you like on the first photo and pull the yarn through both. Now, take both ends of the yarn and get them through the channel that begins in the chest of the mascot and comes out again of its left leg; with yarn, this is hard, so I knotted the ends to a piece of wire which let me pass them through the cannel easily. Now place the arms on the shoulder shafts; they will fit when done carefully -- don't force this, so you don't snap the head off or break the joints.
Test the function of the arms: pull on the yarn ends from below. The arms should lift with minimal force and fall down again as soon as you let go of the pullstring. If they don't, take your files and knife and stuff and search the chest of the mascot as well as the joints of the wings for printing inaccuracies, rough parts, filament stringing etc. Don't continue before this motion works smoothly.
Now, pull the two ends of the yarn through the hole in the bonnet down, to connect it to the rotating pin.
The next part can also be a little tricky: basically, you want to make a knot in the yarn ends just below the pin in a position so the arms are lifted as high as is easily possible (not higher!) when the pin is lowest during the wind wheel rotation. For this, I recommend putting the hood in a slightly upright position and fix the wind wheel in its position (with the pin lowest) by sticking pencils through the grille to block the weel (see photo). Now pull the ends of the yarn until the wings reach their high position, without stretching anything, and make a double knot below the pin; it might be a good idea to make a loop in the second knot, so you can loosen it again if you didn't get the tension right -- trust me, this can take some tries!
As you can see on the photos, I made another knot slightly above the pin to stop it from getting of the pin, but still loose enough so the yarn isn't wrapped around the pin when the wheel rotates. In the end, I don't think this was necessary.
When done, test: the wind wheel should spin easily, moving the arms as much as possible. If you notice a little resistance in wheel rotation when the pin is lowest, this indicates the yarn is stretched -- this won't work later, it just won't rotate. Do it right now, loosen that knot and try again.
Step 4: Mount It on Your Bike
You're nearly done. I hope you adhered to my advice in step 1 and checked your bike first. You should be able to press the hood on the handlebar with some force; it's deliberately designed as a tight fit. Most bikes have bowden cables here that will prevent the hood from tilting forward and down, so this alone might work for you. If you want it mounted more securely or you don't get the right position right away, you can print 2 mountclip.stl parts: they fit into a recess in the hood's clips on one side, and on the other side you can push in an m3 screw from below and screw it into an M3 nut above.
Step 5: Have Fun!
And off we go, show off to the neighbourhood! It's normal for the wheel to take a few meters to get into rotating, but after that it worked at comfortable speeds for me. I hope you like it :)
The wings are beautiful but seem to need more work until the balance is right. In the future I'd love to have a small handle on the hood to temporarily turn off the flapping while riding your bike. I think this might be done easily: the lever would just lift or lower a cam that tightens or loosens the pullstring. If I manage to make such an addition, I will try to make it in a way so you don't have to print the hood again.
If you like the Bicycle Mascot and my instructable, please consider voting for me in the 3d printing contest! Thank you :)
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