Window blind

A window blind is a specific type of window covering which is made with slats of fabric, wood, plastic or metal that adjust by rotating from an open position to a closed position by allowing slats to overlap. Metal window blinds are often used outside of the house or business to protect against theft, temperature, vision, bad weather and fire (in fire-prone areas). Often these blinds are machine-operated, rather than hand operated.
The horizontal version uses a thin woven "ladder" system to suspend the slats and enable slats to be closed via a rotating drum to which each upper end of the woven ladder is wrapped and attached. A lift cord allows the blind to be pulled up and stack tightly to top of window when desired.
The vertical version uses a generally wider slat and has the added feature of being able to pull a cord to stack the slats together either to one side or to separate in the center and stack on each end. This vertical blind allows rotation of slats by a rotating shaft in the upper head rail housing which runs through independent geared carriers that will convert twisting of tilt rail to a rotation of each individual slat in synchrony. The original vertical blinds were invented in Kansas City, Missouri, by Edward Bopp and Fredrick Bopp who held the original patent. The company name at the time was Sun Vertical. In the 1960s the patent and company was sold.
The term window blinds is also sometimes used, somewhat inaccurately, to describe window coverings generically—in this context window blinds include almost every type of window covering, i.e. shutters, roller blinds, roman blinds and of course, vertical and horizontal blinds.
In Britain awnings are also considered blinds. A blind limits observation and thus “blinds” the observer to the view. The main types are slat blinds which can be opened in two ways and solid blinds.
Solid blinds can only be raised or lowered and are sometimes called shades. There are types of blinds, such as Holland blinds and woven-wood blinds, where there are small spaces between the slats. In others such as pleated shades there are no spaces because the slats are sewn inside fabric.
Window blinds reduce the heat from sunlight. Ancient Egyptian pharaohs had blinds made of reeds. The most inexpensive blinds in the 1800s were home-made roller blinds, made of cloth.
Window blinds can be manually drawn using a cord, or automated through motorization. Controls for motorized blinds can be from a wall switch or keypad, remote control, or a personal computer, eliminating the need for cords and allowing control of otherwise inaccessible windows. A number of homes are integrating blind control with central CBUS solutions. This control provides ease of use, but is also effective to control blind operation to reduce heat loss during winter or heat effects during summer.