A zipper (British English: zip or (rarely) zip fastener) is a popular device for temporarily joining two edges of fabric. It is used in clothing (e.g. jackets and jeans), luggage and other bags, sporting goods, camping gear (e.g., tents and sleeping bags), and other daily use items.

Description

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.1 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.

Some zips have two slides, allowing variation in the opening's size and position. In most jackets and similar garments, the opening is closed entirely when one slide is at each end. In most baggage, the opening is closed entirely when the two slides are next to each other at any point along the zipper.

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.
• 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.
• decorate an item.

These variations are achieved by sewing one end of the zipper together, sewing both ends together, or allowing both ends of the zipper to come completely apart.

A zipper costs relatively little, but if it fails, the garment may be unusable until the zipper is repaired or replaced -- which can be quite difficult and expensive. Problems often lie with the zipper slider; when it becomes worn it does not properly align and join the alternating teeth. If a zipper fails, it can either jam (i.e. get stuck) or partially break off.

Hook and eye model

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.