K'nex "Leave Me Alone" Box





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Uploaded on Aug 14, 2010

You turn it on, it turns itself off.

It seems everybody is building one of these "leave me alone" boxes or "useless machines" or whatever they are called, so I thought I would try my hand at building my own. This box is 100% mechanical (the electric motor always turns the same direction) and, unlike some other mechanical boxes I have seen, the position of the switch directly determines the direction of the arm, rather than just having it on a reciprocating axle. The mechanism for this box took 6 hours to design, build and fine-tune. The completed box uses about 650 pieces (including 14 gears) and measures 1 foot wide, 1.5 feet long and 6 inches high.

How it Works - WARNING: TL;DR

I will try to explain this as well as I can for the 2 or 3 people who actually care. The blue lever on the far left is the "switch" which turns the machine on or off. When the switch is pulled, a series of needlessly complex linkages cause 2 things to happen. One: the transmission in the center of the device (an extremely downsized, re-designed version of the one found in my automatic transmission) is switched in to the "forward" position. Two: the "clutch" is engaged, by pulling the red gear farthest to the right into position so it meshes with the gear coming off the motor, as well as the drive gear for the rest of the machine. 14 gears later, the large L-shaped arm in the center of the device swings forward and hits the switch. Due to the design of the linkages, this only switches the transmission, but does not disengage the clutch. The transmission reversed, the arm goes back into its resting state. At the end, it engages a rod which slides the clutch gear out of position, stopping the machine in its starting point

Frequently Asked Questions:

Q. WHY???
A. I dunno, it was a fun design challenge.

Q. No, really, why?
A. I'm serious, this thing has no real purpose whatsoever.


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