Power windows or electric windows (American English) as well as electric or power window lifts (British English)[1] are automobile windows which can be raised and lowered by depressing a button or switch, as opposed to using a hand-turned crank handle.
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Packard introduced the first power windows (along with automotive air-conditioning systems) in the 1940 Packard 180 series.[2] This was a hydro-electric system. In 1941, the Ford Motor Company followed quickly with power windows on the Lincoln Custom (only the limousine and seven-passenger sedans).[3] Cadillac had a straight-electric divider window (but not side windows) on their series 75 limousines immediately prior to World War II.
Power assists originated in the need and desire to move convertible body-style tops up and down by some means other than human effort. The earliest power assists were vacuum-operated and were offered on Chrysler Corporation vehicles, particularly the low-cost Plymouth convertibles in the late 1930s.
Shortly before World War II, General Motors developed a central hydraulic pump for working convertible tops[4]. This system was introduced on 1942 convertibles built by GM. Previously, GM had used a vacuum system which did not have the power to handle increasingly larger and complex (four side-windows vs. only two) convertible top mechanisms.
The June and July 2010 issues of "The Self-Starter", the official magazine of the International Cadillac-LaSalle Club, contain references to the use of various types of power window mechanisms in pre-WWII specially modified Cadillac sedans. These Cadillac-built (as opposed to private coachbuilder) models used three types of power mechanisms - straight electric, straight vacuum (much as the power antenna mechanisms used on Cadillacs through 1955) and the soon-to-be-standard electro-hydraulic system. The July 2010 edition also references a 1941 specially modified Cadillac Model 6219 four-door sedan built for the Chairman of the GM Board, Alfred P. Sloan, that had power window mechanisms, although the type is not specified. [5]
Chief Engineer of the Buick Division, Charles A. Chayne, "...had introduced an electrically controlled hydraulic system into the 1946 Buick convertibles that provided fingertip operation of the top, door windows, and front seat adjustment".[6] Apparently Chayne was a pioneer in these types of systems. These systems were based on major hydraulic advances made in military weapons (tanks, aircraft) in preparation for World War II.
The "Hydro-Lectric" system (windows, front seat adjustment and convertible top) was standard on 1947 model year [7]. It was probably standard on some 1946 convertible models. Despite the fact that no specific documentation has been found in sales literature (on internet searches), the January 2011 issue of "The Self-Starter", the official magazine of the Cadillac-La Salle Club, lists a 1946 model 6267D Convertible for sale with "hydraulic windows". However, a 1946 Buick Convertible advertised on eBay had roll-up windows, indicating a production change after introduction. This appears to confirm that the accessory (including the electro-hydraulic front bench seat and convertible top) were available on post-war Cadillac models or at least shortly after introduction of the 1946 models..
The seat and window assist system was nor available on GM closed cars (standard on some Cadillac Series 75 models). The full system was standard only on the high-end GM convertibles made by Oldsmobile, Buick, and Cadillac. It was only available as a package; that is, power assisted windows, front seat and convertible top (where applicable). This feature can be identified in 1948 and later General Motors model numbers with an "X" at the end, such as the 1951 Cadillac Sixty Special sedan, model 6019X [8].
Ford also had a similar electro-hydraulic system on higher-end convertibles Mercury and Ford Sportsman convertibles (with wood trim) were equipped with power windows on four windows from 1946 through 1948. (Mercury and Lincoln) by 1951[9]. These systems were used by other luxury car models (Imperial and Packard) until Chrysler introduced the all-electric operation on the 1951 Imperial. General Motors also followed with full electric operation in 1954. This included four-way and then six-way seats, which were introduced in 1956. Chevrolet introduced the oddity of power front windows (only) in the 1954 model. Ford also introduced full four-door power windows in sedans in 1954.
Electrically-operated vent windows were available as early as 1956 on the Continental Mark II. The 1960s Cadillac Fleetwood came standard with power front and rear vent windows, in addition to standard power side windows, for a total of eight power window controls on the driver's door panel.
Modern heavy-duty highway tractors frequently have an option for power window controls; however, these are generally what is referred to as "straight air". That is, the compressed air system used for air brakes is also used for the windows. These types of trucks have long used compressed air cylinders for seat height adjustment. In a similar fashion to the electro-hydraulic system, the compressed air is merely released to lower the window and/or seat. The compressed air is then admitted to the respective cylinder to raise the window or seat.
In a typical auto/light truck installation, there is an individual switch at each window and a set of switches in the driver's door or a-frame pillar, so the driver can operate all the windows. These switches took on many different appearances, from heavy chrome plate to inexpensive plastic.
However, some models like Saab and Holden have used switches located in the center console, where they are accessible to all the occupants. In this case, the door-mounted switches can be omitted.
Power windows are usually inoperable when the car is not running as the electrical system is not "live" once the ignition has been turned off. The Hydro-Lectric system; however, could lower the windows at rest, since pressure from the hydraulic system was merely released to lower the window. Raising the windows required the pump to operate (at a fairly high noise level) and introduce pressure at each cylinder. These hydraulic systems also required pressure lines to each cylinder (door, seat and top) and tended to leak.
Many modern cars have a time delay feature, first introduced by Cadillac in the 1980s, called retained accessory power. This allows operation of the windows and some other accessories for ten minutes or so after the engine is stopped. Another feature is the express-down window, which allows the window to be fully lowered with one tap on the switch, as opposed to holding the switch down until the window retracts. Many luxury vehicles during the 1990s expanded on this feature, to include express-up on the driver's window, and recently, some manufacturers have added the feature on all window switches for all passengers convenience. This is done by activating the switch until a "click" response is felt.
Power windows have become so common that by 2008, some automakers eliminated hand cranks from all models. So many vehicles have power windows that some people no longer understand the (formerly) common sign from another driver of using their hand to simulate moving a window crank to indicate that they wish to speak with someone (stopped at a light or in a parking lot).
Power windows have come under some scrutiny after several fatal accidents in which children's necks have become trapped, leading to suffocation. Some designs place the switch in a location on a hand rest where it can be accidentally triggered by a child climbing to place his or her head out of the window. To prevent this, many vehicles feature a driver-controlled lockout switch, preventing rear-seat passengers (usually smaller children) from accidentally triggering the switches. This also prevents children from using them as toys and pets riding with their heads out windows from activating the power window switch.
Starting with the 2008 model year, U.S. government regulations required automakers to install power window controls that are less likely to be accidentally activated by children.[10] However, the rules do not prevent all potential injuries to a hand, finger, or even a child's head, if someone deliberately holds the switch when the window is closing. In 2009, the U.S. auto safety administration tentatively decided against requiring all cars to have automatic reversing power windows if they sense an obstruction while closing.[11] Proposed requirements concern "one-touch" up window systems, but most vehicles with this feature already have automatic-reversing.[12] The federal government made a written contract that all automakers should make the lever switches (as opposed to the rocker and toggle switches) standard on all new vehicles by 1 October 2010.[13]
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