A handle is a part of, or attachment to, an object that allows it to be
grasp
A grasp is an act of taking, holding or seizing firmly with (or as if with) the hand. An example of a grasp is the handshake, wherein two people grasp one of each other's like hands.
In zoology particularly, prehensility is the quality of an ap ...
ed and
manipulate
Manipulation may refer to:
* Manipulation (psychology) - the action of manipulating someone in a clever or unscrupulous way
*Crowd manipulation - use of crowd psychology to direct the behavior of a crowd toward a specific action
::* Internet mani ...
d by
hand
A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "h ...
. The design of each type of handle involves substantial
ergonomic
Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Four primary goals of human factors learnin ...
issues, even where these are dealt with intuitively or by following tradition. Handles for
tools
A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many animals use simple tools, only human beings, whose use of stone tools dates ba ...
are an important part of their function, enabling the user to exploit the tools to maximum effect.
Package handle
Package handles, or carriers, are used to help people use packaging. They are designed to simplify and to improve the ergonomics of lifting and carrying packages. Handles on consumer packages add convenience and help facilitate use and pouring. ...
s allow for convenient carrying of packages.
General design criteria
The three nearly universal requirements of are:
# Sufficient strength to support the object, or to otherwise transmit the force involved in the task the handle serves.
# Sufficient length to permit the hand or hands gripping it to reliably exert that force.
# Sufficiently small
circumference
In geometry, the circumference (from Latin ''circumferens'', meaning "carrying around") is the perimeter of a circle or ellipse. That is, the circumference would be the arc length of the circle, as if it were opened up and straightened out to ...
to permit the hand or hands to surround it far enough to grip it as solidly as needed to exert that force.
Specific needs
Other requirements may apply to specific handles:
* A sheath or coating on the handle that provides
friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:
*Dry friction is a force that opposes the relative lateral motion of t ...
against the hand, reducing the gripping force needed to achieve a reliable grip.
* Designs such as recessed car-door handles, reducing the chance of accidental operation, or simply the inconvenience of "snagging" the handle.
* Sufficient circumference to distribute the force comfortably and safely over the hand. An example where this requirement is almost the sole purpose for a handle's existence is the handle that consists of two pieces: a hollow wooden cylinder about the diameter of a finger and a bit longer than one hand-width, and a stiff wire that passes through the center of the cylinder, has two right angles, and is shaped into a hook at each end. This handle permits comfortable carrying, with otherwise bare hands, of a heavy package, suspended on a tight string that passes around the top and bottom of it: the string is strong enough to support it, but the pressure the string would exert on fingers that grasped it directly would often be unacceptable.
* Design to thwart unwanted access, for example, by children or thieves. In these cases many of the other requirements may have reduced importance. For example, a child-proof doorknob can be difficult for even an adult to use.
Pull handles
One major category of handles are ''pull'' handles, where one or more hands grip the handle or handles, and exert force to shorten the distance between the hands and their corresponding shoulders. The three criteria stated above are universal for pull handles.
Many pull handles are for lifting, mostly on objects to be carried.
Horizontal pull handles are widespread, including
drawer pull
A drawer pull (wire pull or simply pull) is a handle to pull a drawer out of a chest of drawers, cabinet or other furniture piece.
A drawer pull often includes a plate to which the handle is fastened. The handle may swing from one or two mou ...
s, handles on latchless doors and the outside of car doors. The inside controls for opening car doors from inside are usually pull handles, although their function of permitting the door to be ''pushed'' open is accomplished by an internal unlatching linkage.
Pull handles are also a frequent host of common
door handle bacteria
Because door handles are commonplace and are interacted with by large numbers of people on a daily basis, they present opportunities for growth of bacterial colonies.
Many factors determine the habitability of a door handle for a population of bac ...
such as
e-coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...
, fungal or other viral infections.
Door Handles Can Spread Germs
retrieved November 2016
Two kinds of pull handles may involve motion in addition to the hand-focused motions described:
* Pulling the starting cord on a small internal-combustion engine may, besides moving the hand toward the shoulder, also exploit simultaneously pushing a wheeled vehicle away with the other hand, stepping away from the engine, and/or standing from a squat.
* Some throwing motions, as in a track-and-field
Track and field is a sport that includes athletic contests based on running, jumping, and throwing skills. The name is derived from where the sport takes place, a running track and a grass field for the throwing and some of the jumping event ...
hammer throw
The hammer throw is one of the four throwing events in regular track and field competitions, along with the discus throw, shot put and javelin.
The "hammer" used in this sport is not like any of the tools also called by that name. It consis ...
, involve pulling on a handle against centrifugal force (without bringing it closer), in the course of accelerating the thrown object by forcing it into circular motion.
Twist handles
Another category of hand-operated device requires grasping (but not pulling) and rotating the hand and either the lower arm or the whole arm, about their axis. When the grip required is a fist grip, as with a door handle
A door handle or doorknob is a handle used to open or close a door. Door handles can be found on all types of doors including exterior doors of residential and commercial buildings, internal doors, cupboard doors and vehicle doors. There are many ...
that has an arm rather than a knob to twist, the term "handle" unambiguously applies. Another clear case is a rarer device seen on mechanically complicated doors like those of airliners, where (instead of the whole hand moving down as it also rotates, on the door handles just described) the axis of rotation is between the thumb and the outermost fingers, so the thumb moves up if the outer fingers move down.
Handles for wide-range motion
The handles of bicycle grips, club-style weapons, shovel
A shovel is a tool used for digging, lifting, and moving bulk materials, such as soil, coal, gravel, snow, sand, or ore.
Most shovels are hand tools consisting of a broad blade fixed to a medium-length handle. Shovel blades are usually made of ...
s and spade
A spade is a tool primarily for digging consisting of a long handle and blade, typically with the blade narrower and flatter than the common shovel. Early spades were made of riven wood or of animal bones (often shoulder blades). After the a ...
s, axe
An axe ( sometimes ax in American English; see spelling differences) is an implement that has been used for millennia to shape, split and cut wood, to harvest timber, as a weapon, and as a ceremonial or heraldic symbol. The axe has ma ...
s, hammer
A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nails into wood, to shape metal (as w ...
s, mallet
A mallet is a tool used for imparting force on another object, often made of rubber or sometimes wood, that is smaller than a maul or beetle, and usually has a relatively large head. The term is descriptive of the overall size and proport ...
s and hatchet
A hatchet (from the Old French , a diminutive form of ''hache'', 'axe' of Germanic origin) is a single-handed striking tool with a sharp blade on one side used to cut and split wood, and a hammerhead on the other side. Hatchets may also be use ...
s, baseball bat
A baseball bat is a smooth wooden or metal club used in the sport of baseball to hit the ball after it is thrown by the pitcher. By regulation it may be no more than in diameter at the thickest part and no more than in length. Although histor ...
s, rackets, golf club
A golf club is a club used to hit a golf ball in a game of golf. Each club is composed of a shaft with a grip and a club head. Woods are mainly used for long-distance fairway or tee shots; irons, the most versatile class, are used for a variety ...
s and croquet
Croquet ( or ; french: croquet) is a sport that involves hitting wooden or plastic balls with a mallet through hoops (often called "wickets" in the United States) embedded in a grass playing court.
Its international governing body is the Wor ...
mallets involve a greater range of ergonomic
Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Four primary goals of human factors learnin ...
issues.
See also
*Hand truck :''"Hand truck" may also refer to Pallet jack.''
A hand truck, also known as a hand trolley, dolly, stack truck, trundler, box cart, sack barrow, cart, sack truck, two wheeler, or bag barrow, is an L-shaped box-moving handcart with handles at one ...
*Shopping trolley (caddy)
A shopping caddy or shopping trolley is a large bag on wheels, used for carrying a large amount of shopping home on foot. The bag is typically made from a waterproof fabric, and wicker basket designs are also sold. The trolleys commonly have two ...
References
{{Commons category, Handles
Human–machine interaction
Door furniture
Tools
Ergonomics