That table top fan you have next to you is more interesting than you think! I took mine apart so I could show you how it works. The "four speed mechanism" releases any other button that was previously pressed down. Once a button is pressed a signal (voltage) is sent to the motor at the top of the fan. The oscillation motion is produced through the 4 bar mechanism. The last part of the video covers the gears that turn the 4 bar mechanism. The pin is part of the gears - when it is lifted the gears don't connect and the fan will no longer oscillate back and forth.