Door handle
Encyclopedia
Door
A door is a movable structure used to open and close off an entrance, typically consisting of a panel that swings on hinges or that slides or rotates inside of a space....
. In the United States, door handle can refer to any fixed or lever-operated door latch
Latch (hardware)
A latch is a type of mechanical fastener that is used to join two objects or surfaces together while allowing for the regular or eventual separation of the objects or surfaces....
device, including on car doors. The term door knob (or simply doorknob) tends to refer to round operating mechanisms.
History
The first documented invention of the door handle appears in U.S. Patent entries for the year 1878 when a patent for improvements on a door-closing device was issued to a man named Osbourn Dorsey. However, the use of doorknobs, as documented by illustrations and shop catalogues, extends back into the 18th century.The traditional door knob has a bolt or spindle running through it that sits just above a cylinder, to which the spindle is connected. Turning the knob pulls the cylinder in the direction of the turn. The end of the cylinder is the latch bolt (more simply known as the latch), which protrudes into a space carved out of the door frame, and which prevents the door from being opened if the knob is not turned. A spring or similar mechanism causes the latch to return to its protruding state whenever the knob is not being turned. Escutcheon plates are typically placed around the knob and the place from which the latch protrudes.
Applications and usage
The location of the door handle on the door may vary between a few centimeters away from the edge of the door to the exact center of the door, depending on local culture, decorative style or owner preference. The distance from the edge of the door to the center of the handle is called the backset.In Europe door levers are more common than the door knob, while in the US, door knobs are traditionally preferred over door handles. However door knobs can be difficult for the young and elderly to operate. For this reason, door handles in most American commercial
Commerce
While business refers to the value-creating activities of an organization for profit, commerce means the whole system of an economy that constitutes an environment for business. The system includes legal, economic, political, social, cultural, and technological systems that are in operation in any...
and industrial
Industry
Industry refers to the production of an economic good or service within an economy.-Industrial sectors:There are four key industrial economic sectors: the primary sector, largely raw material extraction industries such as mining and farming; the secondary sector, involving refining, construction,...
buildings and in many households use a lever-operated handle, rather than a knob, as the lever does not require a tight grip. Levers are also beneficial on doors with narrow stile widths where the reduced backset leaves insufficient space to comfortably turn a door handle.
Most household door handles use a simple mechanism with a screw-style axle (called a spindle) that has at least one flat side, which is passed through the door jigger, leaving some length exposed on each side of the door to which the handles are attached. Some handles are attached on both sides by screwing or sliding them directly onto the spindle, and then securing one or more retaining screws (set screws) through the knob perpendicular to the flat of the spindle
Spindle
The term spindle may refer to:In textiles and manufacturing:*Spindle , a device to spin fibres into thread*Spindle , is the main rotating part of a machine tool, woodworking machine, etc...
. Handles that lose traction can frequently be repaired by replacing or adjusting the set screw, which prevents them from slipping on the spindle. Other types of handles, typically used in Europe, slide onto the spindle but are affixed only to the door itself without use of set screws.
Types of household handles:
- Entrance: These door handles are typically used on exterior doors, and include keyed cylinders.
- Privacy: Typically used on bedroomBedroomA bedroom is a private room where people usually sleep for the night or relax during the day.About one third of our lives are spent sleeping and most of the time we are asleep, we are sleeping in a bedroom. To be considered a bedroom the room needs to have bed. Bedrooms can range from really simple...
s and bathroomBathroomA bathroom is a room for bathing in containing a bathtub and/or a shower and optionally a toilet, a sink/hand basin/wash basin and possibly also a bidet....
s; while they are lockable (unlockable with a generic tool), they do not have keyed cylinders. - Passage: Also known as hall or closet, these do not lock and are used in hall or closet doors.
- Dummy: These types are used for ball catch doors or other applications where a jigger mechanism is not needed, but a similar aesthetic effect is desired.
Car door handles might protrude from the vehicle's exterior surface or be streamlined into the vehicle's contour. In some automobiles, especially luxury vehicles
Luxury vehicles
Luxury vehicle is a marketing term for a vehicle that provides luxury — pleasant or desirable features beyond strict necessity—at increased expense ....
, the door handles might be decorated with chrome and feature a key-less entry pad utilizing either a numerical code or thumb scan.
Foldable door handle
On a balcony whose door has an outside shutter, a special door handle is used on the outer side. The protruding part of such handle (usually ring-shaped) can be folded sideways, so that the shutter can be fully closed without being obstructed by the door handle.Infection control
Of concern is the fact that door handles are instrumental in the spread of many infections. However, some materials, e.g. brassBrass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
, copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
and silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, are slowly poisonous to many germ
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
s. The exact mechanism is not known, but is commonly thought to be via the oligodynamic effect
Oligodynamic effect
The oligodynamic effect was discovered in 1893 by the Swiss Karl Wilhelm von Nägeli as a toxic effect of metal ions on living cells, algae, molds, spores, fungi, viruses, prokaryotic and eukaryotic microorganisms, even in relatively low concentrations...
, perhaps by some other electrostatic effect. Brass and copper, for example, disinfect themselves of many germs within eight hours. Other materials such as glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
, porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...
, stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
and aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
do not have this effect. Self-disinfecting door handles are particularly important in hospital
Hospital
A hospital is a health care institution providing patient treatment by specialized staff and equipment. Hospitals often, but not always, provide for inpatient care or longer-term patient stays....
s, but useful in any building
Building
In architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...
.