How does a zipper work?
The zipper has two edges of teeth and hollows which fit into each other very snugly when the zipper is closed.
A zipper is a slide fastener often used in place of buttons, snaps, etc., to fasten clothing, luggage and other articles. A zipper is made of two rows of plastic or metal teeth, clamped to strips of corded tape. The tenth are opened and closed by pulling a Y-shaped sliding piece.
As the slider is pulled up, it meshes the rows of teeth together. The wedge on top of each tooth locks snugly into the hollow undersided of the tooth above it.
When joined, the teeth cannot be separated except by pulling the slider down to unmesh them.
Little metal pieces called stops are clamped on to the bottom and top of the zipper so that the slider won’t slide off the zipper.
Zipper factories make zippers in one long strip, and then cut the long zippers into individual zippers.
In 1924, the B.F. Goodrich Company gave the trade name “zipper” to rubber galoshes closed by the fastener. The name is now used for the fasteners themselves. – Dick Rogers