Zipper

A zipper, zip, fly, or zip fastener, formerly known as a clasp locker, is a commonly used device for binding together two edges of fabric or other flexible material. Used in clothing (e.g. jackets and jeans), luggage and other bags, camping gear (e.g. tents and sleeping bags), and many other items, zippers come in a wide range of sizes, shapes, and colors. In 1892, Whitcomb L. Judson, an American inventor from Chicago, patented the original design from which the modern device evolved. The zipper gets its name from a brand of rubber boots (or galoshes) it was used on in 1923. The galoshes could be fastened with a single zip of the hand, and soon the hookless fasteners came to be called "Zippers". A zipper consists of a slider mounted on two rows of metal or plastic teeth that are designed to interlock and thereby join the material to which the rows are attached. The slider, usually operated by hand, contains a Y-shaped channel that, by moving along the rows of teeth, meshes or separates them, depending on the direction of the slider's movement. The teeth may be individually discrete or shaped from a continuous coil, and are also referred to as elements. The word zipper is onomatopoetic, because it was named for the sound the device makes when used, a high-pitched zip. In many jackets and similar garments, the opening is closed completely when the slider is at the top end. Some jackets have double-separating zippers with two sliders on the tape. When the sliders are on opposite ends of the tape, the jacket is closed. If the lower slider is raised then the bottom part of the jacket may be opened to allow more comfortable sitting or bicycling. When both sliders are lowered then the zipper may be totally separated. Bags, suitcases and other pieces of luggage also often feature two sliders on the tape: the part of the zipper between them is unfastened. When the two sliders are located next to each other, which can be at any point along the tape, the zipper is fully closed.