Zippers

The bulk of a zipper consists of two strips of fabric tape, each affixed to one of the two pieces to be joined, carrying tens or hundreds of specially shaped metal or plastic teeth. These teeth can be either individual or shaped from a continuous coil, and are also referred to as elements. The slider, operated by hand, moves along the rows of teeth. Inside the slider is a Y-shaped channel that meshes together or separates the opposing rows of teeth, depending on the direction of its movement. The friction and vibration of the slider against the teeth causes a characteristic buzzing noise, which is probably the origin of the name zipper. The name also may have originated in the greater speed and ease with which the two sides of a zipper can be joined, compared to the time needed for fastening laces or buttons.

Zippers may increase the size of an opening to allow the passage of objects, as in the fly of trousers or in a pocket join or separate two ends or sides of a single garment, as in the front of a jacket, dress or skirt. In attach or detach a separable part of the garment to or from another, as in the conversion between trousers and shorts or the connection / disconnection of a hood and a coat. It decorate an item.

An early device superficially similar to the zipper, "an Automatic, Continuous Clothing Closure", was patented in the United States by Elias Howe in 1851. Unlike the zipper, Howe's invention had no slider; instead a series of clasps slid freely along both edges to be joined, with each clasp holding the two sides together at whichever pair of points along them it was located. The clasps were joined together by a string, which, when pulled taut, caused the clasps to be evenly spaced along the closure, thus holding the two edges together. Pulling in the other direction caused the clasps to become bunched up at one end, by which means the device was opened.

Metallic zippers are the classic zipper type, found mostly in jeans today. The teeth are not a coil, but are individual pieces of metal moulded into shape and set on the zipper tape at regular intervals. Metal zippers are made in brass, aluminium and nickel, according to the metal used for teeth making. All these zippers are basically made from flat wire. A special type of metal zipper is made from pre-formed wire, usually brass but sometimes other metals too. Only a few companies in the world have the technology. These type of pre-formed metal zippers are mainly used in high grade jeanswear, workwear, etc., where high strength is required and zippers need to withstand tough washing.