Sound familiar? It’s hard to imagine life without zippers. We’ll see how engineers made it an open and shut case, today on Engineering Works.
Back in the o-o-o-ld days, getting dressed meant fastening buttons or hooks one by one on your jacket and shoes; took forever. Imagine how late you’d be. An early zipper – called the clasp locker – was displayed at the Chicago World’s Fair in 1893. It used a sliding pull-tab that pulled together rows of hooks and eyes, kind of like a zipper. But not quite. They were awkward and tended to come apart at the worst times. Fine for mailbags and shoes, but not quite ready for your jeans.
A better version, designed around World War I, had tiny metal bars, or teeth, instead of hooks and eyes. It showed up in Navy life vests and Army gear. By the 1930s, people were buying clothing with zippers. Today, zippers are made of plastic, nylon and other materials besides metal. But they still work much like the ones American soldiers wore almost 90 years ago.
Zippers use two simple tools, the wedge and the hook, to form a chain of interlocking teeth. When you pull the tab to close a zipper, tiny wedges inside force the two rows of teeth together. Each tooth is hooked so it meshes with the shape of the opposite tooth. The teeth stay locked together until you pull the tab and the wedges push the teeth apart.
Zippers got their name in 1925 when the BF Goodrich company used the invention on a new rubber boot and coined the term from the sound they made.
Well, time to go.