Multi-Mode, Rubber Band-Powered ... Toy

Kerry Burton

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Orem, Utah
I thought I would give a little background, and some additional information on my recent Toy Swap entry.

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An 8-year-old neighbor kid recently showed me a book with about a dozen small Lego projects. The book had a kind of "blister pack" attached at the bottom, containing the Lego parts needed to make all of the projects. He proudly flipped through the book, showing me the projects he had made so far (just about ALL of them).

One page showed a sophisticated plastic version of something I recognized from my childhood ... a simple toy made from a wooden spool, a couple matchsticks, a piece of candle wax or soap, and a rubber band. Here is the version from the old World Book / Childcraft Make and Do book that we had growing up:

SpoolTractor_Childcraft_MakeAndDo_Page299_Cropped.jpg


Here's a modified version that I whipped up with my niece a couple weeks ago. We were going for speed rather than the slow-motion, hill-climbing "tractor" action that is usually mentioned in "How To" articles. Note the thin sheet of clear plastic between the bead and the spool...

A590_2329_ActualSpoolTractor_PencilSide.jpg


A590_2328_ActualSpoolTractor_ThumbtackSide.jpg



While I wasn't watching, someone (my Dad, maybe?) put a knot in the rubber band, which actually helped it run better. I'm thinking that it kept the twisted part of the band away from the edge of the hole, which reduced friction:

A590_2330_ActualSpoolTractor_KnottedBand.jpg



Here is another variation (among MANY) that I found online - from page 181 of the Nov 1959 issue of Popular Mechanics:

SpoolTankToy_PopularMechanics_Nov1959_Page181.gif



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| ANYWAY...!! |
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All of this got me thinking. An idea for a "multi-mode" version of the toy popped into my head, and I planned to work one up for the neighbor kid. Before that happened, I signed up for the 2011 Toy Swap ... so an FWW member got the first version instead. After approximately 20 shop hours (including major mistakes and at least one total restart) I came up with this:

A590_2324_DualModeRubberBandTank_PartsAndTools.jpg


I call it a "Multi-Mode, Rubber Band-Powered Roller". (It's not really a "tank" or "tractor" ... although with some redesign it probably could be.) There are currently two different ways to configure it:

"Single Mode" ...

A590_2323_DualModeRubberBandTank_ClassicMode.jpg



... and "Dual Mode".
Note the wide blue rubber bands for providing traction. They were salvaged from broccoli stalks, as purchased at the grocery store. They can/should be used in "Single Mode" too ... not sure why I took them off.
A590_2308_DualModeRubberBandTank_YokeMode.jpg



The key to the two modes is the method of anchoring the "propulsion" rubber band(s):

A590_2312_DualModeRubberBandTank_ModeEnablers.jpg



To set up either mode, you have to pop off the end caps. They're in there pretty tight, and they're pretty smooth, so I chiseled out a couple of "screwdriver insert points":

A590_2311_DualModeRubberBandTank_EndCapSlot.jpg


A590_2317_DualModeRubberBandTank_RemoveEndCap.jpg



"Single Mode" uses a metal screw on one end instead of a thumb tack or matchstick:

A590_2321_DualModeRubberBandTank_SingleModePin.jpg



I mounted the screw on the lathe and used a file to turn away the threads in the center, so it wouldn't cut the rubber band:

A590_2322_DualModeRubberBandTank_SingleModePin_2.jpg




"Dual Mode" uses a center pin to provide driving torque from both ends (at the expense of a shorter run time). You could use a single, long rubber band if you have one. I used two overlapping bands instead. Either way, the pin has to go through the "hole" in the rubber band(s).

A590_2314_DualModeRubberBandTank_DualModePin.jpg


The center pin arrangement was one of the trickier subsystems to figure out. Why didn't I just use another screw? Well, I reasoned that the "user" would need a better (more open) view when trying to situate the rubber band(s) around the center pin. Maybe the removable end caps make that unnecessary; I don't know. Anyway, I:
  • Drilled and tapped the large block while it was still square-sided
  • Turned a "bolt blank" on the lathe (basically a two-diameter dowel)
  • Used a threading die box from Beall to put threads on the smaller diameter
  • Turned away some of the bulk in the middle of the "bolt"
  • Mounted the "bolt" tightly in the block and turned the ends flush as I rounded out the block
  • Used a Dremel tool with a cutoff wheel to make a slot on one end of the "bolt", so it can be tightened/loosened with a flathead screwdriver
When I turned away too much of the "bolt" threading to work with the first block I made, I opted to start over with a second block rather than make another center pin. :eek:


I made a "band puller" from a piece of 12-gauge ground wire, but just about anything will work:

A590_2315_DualModeRubberBandTank_BandPuller.jpg



The body and the long "rolling pin" of this prototype are made of purpleheart, and the center pin is made of hickory. For the end caps and "legs" I used a new-to-me wood:
A590_2325_DualModeRubberBandTank_GranadilloWood.jpg



I ran out of time before I could put a finish on the toy, so you get to imagine the finish of your choice!

Now, to salvage the original block and make a copy for that neighbor kid.... :doh:
 
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Kerry,

Thanks for the fantastic tutorial here. I love that the center 'bolt' is made of wood. Just makes the whole thing that much cooler! :thumb: :thumb:
 
Kerry, I recognize that toy!!!!!!! :rolleyes:;):thumb::thumb:
I honestly had never seen one before in my life and had no idea what it did or was for. I can see races and pulls (little weight sleds) as a way to grade them for my students. I again greatly appreciate the toy, this tutorial and the great idea for a project for my students. :thumb::thumb:
 
I can see races and pulls (little weight sleds) as a way to grade them for my students. I again greatly appreciate the toy, this tutorial and the great idea for a project for my students. :thumb::thumb:

Sounds like fun! I look forward to seeing the variations, improvements, and ... wacky paint jobs? ... your students come up with. I can imagine some entrepreneur in the corner of the shop, selling "upgrades" like:
  • thicker rubber bands
  • heftier "single mode" screws
  • graphite lubricant for the friction points
  • glycerin for the rubber bands
  • etc
:rolleyes:



Never in my wildest dreams could I have concieved of your "Rolls-Royce" of spool vehicles.

"Rolls-Royce" eh? To quote Vizzini from The Princess Bride ... "Just wait till I get going!"

Actually, I don't see myself making a lot of these; this first one might be as fancy as they get. :dunno:
 
OK Kerry, tell the truth: This is you (a few years ago) in the illustration, right?

SpoolTankToy_PopularMechanics_Nov1959_Page181.gif


I can see the resemblance in your avatar photo.

:D :D :D :D :D
 
Naw ... I wasn't born till almost 3 years later. My oldest brother was around, but only about 8 months old when the mag came out.

I guess if you've seen one kid, you've seen 'em all? :rofl:
 
That's really cool! I remember having one of those as a kid. One of my uncles made one for me! I had alot of fun with it!!:D:thumb:
Some kids are going to have a blast with the new ones! Great job!!
 
Those look like fun... I remember either my dad or my grandfather making one of those for me to play with as a tyke...(that was about a week after they invented rubber or maybe spools )... great idea for kids to use their imagination on... something they don't get to do much any more.
 
Kerry,
I took the liberty of downloading your pictures and plans for future use... hope you don't mind. I created a PDF file in my to-do list of things to work on.... this one looks like a lot of fun... just wish I had or someday will have a grandson to share with... all my granddaughters are beyond the age of little toys like this.
 
I took the liberty of downloading your pictures and plans for future use... hope you don't mind. I created a PDF file in my to-do list of things to work on.... this one looks like a lot of fun...

Go for it! I'm actually looking forward to seeing the different variations / improvements that folks might come up with. :thumb:

This is the idea that I discussed with Richard Raffan when he stuck around to do a Saturday demo for our local woodturning club, after the Utah Woodturning Symposium this year. He reminisced about the old spool-based "tank" and hoped he would remember this project as something to work on when he got back home. He even suggested that I submit a write-up to a magazine.

So ... all I ask is that you give me "first crack" at the magazine article thing. :rolleyes:

One of my early sketches looked less like a plain cylinder and more like the little ship that Darth Vader escaped in, in the first (released) Star Wars film ... with a hump in the middle like a rear axle differential, connected to a "wheel" on the end by a narrower section. I'm sure there are all kinds of cool designs that people could whip up.

Enjoy! :wave:
 
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