Marble Machine One
After the Christmas 1996 holidays, much of which my brother Markus and I spent working on better marble machines out of Lego, I thought it was a shame that the machine we built was only made out of Lego. So I started experimenting with building a more permanent marble machine out of wood. This became what I now call Marble Machine 1.
I started by tinkering around with building a marble pump embodying the same principles as the pump in the Lego marble machine, but out of wood. Although the principle was the same, the arrangement of some of the parts was different. The resulting marble pump, with the rest of the marble machine removed, is shown below.
This view shows the pump with the intake and exit attachment removed. Visible is the slider, with the hole in which the piston sits, plus a marble for reference. On the right is a 115 volt AC induction motor. The chain drive provides another bit of reduction. The white sprocket on the left is not directly coupled to the crankshaft, but has a form of slip clutch instead. This slip clutch prevents damage when the machine jams, and also, by being very jerky, can cause jams to become undone on their own. The block with the hole in it is the slider, while the hole is where the piston sits. The crankshaft is made from bent coat hanger wire, and goes through the piston in the slider. Various escapements are cut out of the inside to give the crankshaft room to turn.
Under normal operation, the marble pump is just this rumbling piece of machinery underneath the table on which all the action happens. Marbles magically disappear in a hole in the table, and are pumped up the central column to descend again.
Marble flipflop mechanism
Every time a marble falls on the flipflop, the top of the rocker directs the marble in one or the other direction. When the marble then rolls in that direction, it flips the rocker on its way down, causing the next marble to be sent in the opposite direction.
Marble machine top view
The overall marble distribution system can be seen better in this photo. There are four descent paths, each making a different noise, and taking a different time for the marbles to descend.
The one on the top left is a simple zig-zag zag for the marbles to descend in, and it takes the marble about 5 seconds to go down that one. On the top right is a spiraling descent path. This one also takes about 5 seconds for the marbles to descend, as the marble loses all of its forward momentum when it goes around a square corner. At the bottom of this spiral (partially obstructed) is a divide by two mechanism. On the bottom left is the divide by six mechanism. The box at an angle at the far bottom left is designed to make a loud clack as the carry marble hits it. On the bottom right is the xylophone descent path. This plays a series of notes as the marble bounces between the various blocks of wood.
Marble divide by six
This mechanism is also the most unreliable part of the marble machine. Sometimes a marble falls down the left before the column is full, causing premature release. Worse yet, on rare occasions the marbles line up in such a way that the marble to release everything jams (normal the marbles are not all the same size, and aren't perfectly round either). Other times, when the marbles get released and roll off the J, they bounce off other parts of the marble machine in such a way that they fall out of the marble machine. You know that a machine is darned sophisticated if it can actually lose its marbles!
Marble machine side view
The sound of the marble machine (72k mp3)
I have brought this machine to work to show off a couple of times. Whenever I turn it on, an instant crowd forms. Everybody always says 'this would be great for kids'. This is far from the truth. Stuff for kids has to be indestructible and simple. This machine is anything but, and small kids would render it non functional in no time flat. Everybody also always makes all kinds of suggestions for how the marble machine could be improved. Catch is, how do you 'improve' a machine that is fundamentally designed to be utterly useless? Like all neat projects I have undertaken, I have contemplated plans for a bigger and better marble machine, but as always, there are too many other interesting things to do for me to spend the time to build a better marble machine.
Note: I wrote the above paragraph before I built Marble Machine 2
I guess one potential use for such a machine would be for things like trade shows or anything else where you set up a booth and try to get people's attention. Whenever one is short of people, turning on the machine for half a minute is sure to draw a crowd! Then one could say "Now that I have your attention, let me tell you about our products, which although totally boring, are much more useful and reliable than this machine!"
I hope this page serves as an inspiration for you to build your own marble machine or similarly fun, entertaining, and utterly useless piece of machinery.