The most intricate and fussy part of any garage door is the garage door opener and its associated nuts, bolts, and hardware. You have to deal with the drive mechanism, the long tracks, the tightly-wound and dangerous springs, the brackets, and more. These all combine to make the garage door open nice and smooth time and time again, no matter how much you use it.
And then you must remember, not all garage door opener parts are created equal- in fact, each brand name and each model has different sizes, shapes, and parts, and some even use completely different mechanisms to operate.
In fact, there are three main category of garage door opener, including chain drive (the most basic, and noisiest), screw drive (slightly quieter but still fairly loud), and rubber belt-drive (the quietest.) These all use similar physics but different specifics to wrench open your door every day.
The most important part of an opener (for generating lift, that is) is the spring. The springs are under a lot of pressure, and they're very powerful once they're in high-tension position. This is what gives them the ability to heave open the massive door, which, if you think about it, is very heavy. If you look inside your garage, you will see your extension springs on each side.
Some use extension springs, and some use torsion springs, depending on whether it's a single or double car sized garage. Torsion springs are attached to a header on the top of the door, and these too can be highly dangerous if tampered with, and can let loose with crippling power. Torsion spring wind, instead of simply expanding and contracting like a slinky. The winding is what creates the tension, and what makes torsion springs so much more dangerous than even the already-dangerous extension springs. Any garage door installation person or garage door service company can attest to the danger in springs. In fact, statistically speaking, sky diving is a safer activity than installing garage door springs.
There are other complicated, moving parts involved in opening such a large door, as well, not the least of which are the cable drums, the vertical and horizontal tracks, the brackets, the track hangers, and too many screws, hinges, and plates to even contemplate counting. All of these little metal and plastic bits are what keeps your garage door running smoothly. So don't forget to WD-40 them every once in a while- they deserve your love!
For more information on installing a new garage door opener or new garage doors, ask the experts at http://www.mesagaragedoors.com