Where did the zipper come from, and how does it work?

No single person invented the zipper in one step. Elias Howe patented an early fastener in 1851, Whitcomb Judson patented a clasp locker in 1893, and the Swedish-American engineer Gideon Sundback made it reliable in the early 1910s. It works through two rows of teeth that a Y-shaped slider presses together or pulls apart. The teeth are shaped so that ordinary forces on a garment cannot unlock them. [1] [2]

In 1851 Elias Howe, who also invented a sewing machine, received a patent for an "Improvement in Fastenings for Garments". Wikipedia describes his device as more like an elaborate drawstring than a true slide fastener, and says he did not seriously try to market it. [1] [2]

In 1893 Whitcomb Judson patented a clasp locker, a system of hooks and eyes closed by a slide, and showed it at the Chicago World's Fair. With Colonel Lewis Walker he founded the Universal Fastener Company. Encyclopedia.com says it failed commercially because it jammed easily, came undone accidentally, and rusted when wet. Judson is sometimes called the zipper's inventor, but his device was not used in clothing. [1] [2] [3]

Gideon Sundback, an electrical engineer, was hired by the company in 1906 to improve Judson's fastener. He raised the number of fastening elements from about four to ten or eleven per inch, set two facing rows of teeth, and used a slider to draw them into one closure. The Dyson Foundation adds that he gave each tooth a dimple on its underside and a nib on top, so the teeth lock into each other. Sources differ slightly on timing: Encyclopedia.com says he had invented the modern zipper by the end of 1913, while Britannica Kids says it went on sale in 1914 and received a US patent three years later. [1] [4] [5] [2] [3]

Because Sundback worked for a company in Canada-linked circles, some people wrongly think he was Canadian or that the zipper began there. Wikipedia calls this a misperception. The name came later: in 1923 B. F. Goodrich bought the invention for rubber boots and called them Zipper Boots, after the sound of the slider. The US government had already bought the fasteners during World War I for items such as uniform trousers and aviator clothing. [1] [2]

A zipper has teeth, also called elements, attached to fabric strips called tape, plus a slider and stops at the ends that keep the slider from coming off. The teeth may be separate pieces or shaped from a continuous coil, in metal or plastic. [1] [6]

Moving the slider one way, its Y-shaped channel guides the teeth one by one into a locked position. Moving it the other way separates them. The locking relies on a small, reversible elastic deformation, in a lock-and-key arrangement. The teeth's shape, size and angle mean forces from wearing a garment cannot pull them apart, and the slider's inclined inner edges bring each pair together at the correct angle. This is why the closure holds when pulled sideways but cannot be done properly by hand. [1] [6]