At the bottom are the buttons to set the fan speed, a dial to adjust the pitch of the fan, and then the pin on top to make the fan move back and forth. You know the drill by now. Your fan might be slightly different but the mechanisms I'm about to show you are probably very similar, unless it's a box fan or one of those tower fans or a bladeless fan.
Coming out the back here is three color-coded wires. Whichever button is pressed will send a signal up the wire to the top of the fan and into the motor to start the fan spinning at whatever speed we choose. At first, the fan will only be pointed in one direction. If we wanna cool off more of the room, then press the pin and the fan starts oscillating, or, in other words, moving back and forth.
All right, let's see what's inside of that gear box. There's a piece that sticks out the back that rotates along with the fan. This is called the worm. When it spins, it kind of looks like it's moving even though it's not. Right next to it is the worm gear. Down below is another gear which is directly attached to the crank.
A planetary gear set has four main parts: the sun, planet gears, ring gear, and carrier. You can see that it sometimes rotates quickly, sometimes slowly, and sometimes even in reverse. But... How does this happen? You will be able to predict the motion of this gear set completely, if you understand one simple fact! When two gears are moving as shown, they should have the same speed at the interface.
Gearbox Motor Fan Assembly
They have a few screws left, they don't know where to put them. If it is your first time, go for it, but take pictures so you know how it looked before stripping the gearbox. I'll remove the screws and of course I'll take advantage of the quick change system to remove the spring now. I won't have pressure inside the gearbox and nothing will spring out of it when I separate the shells.
This is the exact opposite to the previous case. At the inner point of the planet gear, the velocity should be zero and the outer points should have the speed of the ring gear. In this case, the planetary spin will reverse in order to satisfy the speed conditions.
Gearbox Motor Fan Assembly
Then remove the gears, mind the small shims here, keep them where they are, it'll prevent you from starting from the beginning, keep the anti-reversal latch because it is required for the pre-cocking feature don't forget any shim remove the trigger. I won't need these anymore same thing for the cut-off lever, it is useless this gun is a bit different because there is an ambidextrous fire selector, so there are extra gears here slide the selector plate forward to remove it.
This will make the planet gear spin and turn at a higher speed. Thus, the carrier will turn at a higher speed. Let's now explore this reverse mechanism of planet gears. For this, what you have to do is just arrest the motion of the carrier.