Alrighty folks, it’s time for my second most favorite season of the year: FALL. I said last time that I would be writing about bicycle gears this time around. I lied. After much thought and greatly appreciated input from Her Excellency Royal Highness Editor-in-Chief Isabella Ziv over some subpar Mexican cuisine in Pierce, I landed on zippers because of jackets and autumnal weather or something like that. With the epic backstory of this piece out of the way, let’s talk about the epic backstory of zippers. Firstly, the technical name for a zipper is a separable fastener. Patented by Gideon Sundback in 1917, not much has changed with the design today, but that does not mean there has been a lack of protection of intellectual property for the sake of corporate gree — pardon, innovation since then. Speaking of, the diagram I yoinked for this article because I was too lazy to model a zipper this week comes from a patent filed yesterday at the time of me writing this article, so probably a week from when you’re reading this.
Nowadays, there is one company that is responsible for 50% of the world’s zippers and for saving us all from the tyranny of the button fly. In fact, I have coined a term for them. You know when you’re in the know? IYKYK? Well if you see a zipper just about anywhere chances are IYKK, i.e. It’s Yoshida Kōgyō Kabushikigaisha. Translating to Yoshida Manufacturing Corporation in English, YKK is a Japanese company based in Tokyo with manufacturing plants all over the world. As I mentioned earlier, although I was too lazy to model a zipper myself, it was not easy finding a technical drawing of a zipper that I liked either. I wanted to show a section view for easy understanding of the underlying principles. I first turned to my favorite things to search through: academic papers. Shockingly, I did find a great free-body diagram, but it was way too grainy, even by the impeccable resolution standards that we here at The Stute abide by.
I was then forced to search through my second favorite type of media for mindless perusing: U.S. patents. Let me tell ya, YKK has more patents related to fasteners than I thought was humanly possible, but the lovely diagram accompanying this article was made possible because of them, so another point on the board for The Man I suppose. I also found a patent for a cane that has an end shaped like a foot for “ergonomic purposes.” Quite the hilarious read if you are interested. The patent numbers for the original zipper patent, the patent that supplied this article’s diagram, and the foot cane are as follows: US-1219881-A, US-20240315402-A1, and US-12096830-B2. Just look up U.S. patent search and you are ready to go.
Back to the actual topic at hand! As a purely mechanical mechanism, zippers are also made out of simple machines. In fact, the zipper is just a bunch of wedges. Each of the tiny bits that get zipped together are called elements. The elements are just small wedges that get wedged together by the flanges on either side of the slider. The slider houses two key elements, the flanges and the diamond. As stated, as the slider is pulled up, the flanges wedge the elements together. When the slider is pulled down, the diamond wedges itself between the elements, wedging them apart. I don’t know if I have ever typed out “wedge” so many times in my life, and I am now in the mood for Doritos. Well, there you have it, a relatively simple, but exceedingly versatile compound machine, found everywhere from my jorts to the aerospace industry. Happy Autumn everybody, and make sure your fly isn’t down when you stunt out in your flyest of Fall fits.
