Handcuffs are restraint devices designed to secure an individual's wrists close together. They comprise two halves, linked together by a chain or hinge. Each half has a rotating part which engages with a ratchet which is closed around a person's wrist. Without the key, the person cannot move their wrists more than a few inches apart, making many tasks difficult or impossible. This is usually done to prevent suspected criminals from escaping police custody.
There are two distinct subtypes of contemporary metal handcuffs: one in which the cuffs are held together by a short chain, and another, of more recent origin, which uses a hinge for this purpose. Since the hinged handcuffs are somewhat smaller when fully extended they are seen as being more easily utilized by a police officer who has relatively small hands, and are also regarded by some observers as more secure because the wrists end up being held closer together than with the chain subtype, and are also bound more rigidly. A third type, the rigid handcuff, has a metal block or bar between the cuffs. Whilst bulkier to carry it permits several variations in cuffing and, with one hand cuffed, can be used in control and restraint techniques. Various accessories are available to improve the security or increase the rigidity of handcuffs, including boxes that fit over the chain or hinge and can themselves be locked with a padlock.
Handcuffs may be manufactured from various metals, including carbon steel, stainless steel and aluminium, or from synthetic polymers.
Sometimes two pairs of handcuffs are needed to restrain a person with an exceptionally large waistline because the hands cannot be brought close enough together; in this case, one cuff on one pair of handcuffs is handcuffed to one of the cuffs on the other pair, and then the remaining open handcuff on each pair is applied to the person's wrists. Oversized handcuffs are available from a number of manufacturers, as are juvenile-sized restraints, though none of the latter in current production are approved for use by the United States National Institute of Justice.
Handcuffs with double locks have a lock-spring which when engaged, usually using the top of the key, stops the cuff from ratcheting tighter to prevent the subject from tightening them, possibly causing injury. Double locks also make picking the locks more difficult.
Plastic restraints, known as PlastiCuffs, or FlexiCuffs, flex-cuffs, tri-fold cuffs, or zip-strips, are lightweight, disposable plastic strips resembling electrical cable ties. They can be carried in large quantities by soldiers and police and are therefore well-suited for situations where many may be needed, such as during large-scale protests. In recent years, airlines began to carry plastic handcuffs as a way to restrain disruptive passengers. Disposable restraints are considered by many to be highly cost-inefficient; they cannot be loosened, and must be cut off to permit a restrained subject to be fingerprinted, or to attend to bodily functions. It is not unheard of for a single subject to receive five or more sets of disposable restraints in their first few hours in custody. Recent products have been introduced that serve to address this concern, including disposable plastic restraints that can be opened or loosened with a key; more expensive than conventional plastic restraints, they can only be used a very limited number of times, and are not as strong as conventional disposable restraints, let alone modern metal handcuffs. In addition, plastic restraints are believed by many to be more likely to inflict nerve or soft-tissue damage to the wearer than metal handcuffs.
On occasions when a suspect exhibits extremely aggressive behavior, leg irons may be used as well; sometimes the chain connecting the leg irons to one another is looped around the chain of the handcuffs, and then the leg irons are applied, resulting in the person being "hog-tied". In a few rare cases, hog-tied persons lying on their stomachs have died from positional asphyxia, making the practice highly controversial, and leading to its being severely restricted, or even completely banned, in many localities.
Most modern handcuffs in Canada, the United States and the United Kingdom can be opened with the same standard universal handcuff key. This allows for easier transport of prisoners and keeps one out of trouble if one loses one's keys. However, there are handcuff makers who use keys based on different standards. Maximum security handcuffs require special keys. Handcuff keys usually do work with thumbcuffs. Recently, a number of padlocks have been marketed which use this same standard key.
In former times, police officers typically handcuffed arrested persons with their hands in front of them, but since approximately the mid-1960s behind-the-back handcuffing has been the standard. The vast majority of police academies in the United States today also teach their recruits to apply handcuffs so that the palms of the suspect's hands face outward after the handcuffs are applied; the Jacksonville, Florida Police Department and the Los Angeles County Sheriff's Department are notable exceptions, as they favor palms-together handcuffing. In addition, suspects are handcuffed with the keyholes facing up (away from the hands) to make it difficult to open them even with a key or improvised pick.
Escaping from handcuffs is a common stunt performed by magicians, perhaps most famously Harry Houdini.
There are ways of escaping from handcuffs:
1. squeezing your hands out
2. lock picking
3. releasing the pawl with a shim
The above methods are often used in escapology.
It is also technically possible to break free from handcuffs by applying massive amounts of force from one's arms to cause the device to split open or loosen enough to squeeze one's hands through, however this takes exceptional strength (especially with handcuffs made of steel). This also puts an immense amount of pressure on the biceps and triceps muscles, and when tried by suspects (even unsuccessfully) can lead to injury, including bruising around the wrists, or tearing the muscles used (including dislocating them off of the bone itself). In reality, only exceptionally strong people, people who are highly emotionally charged or under the influence of stimulant drugs such as methamphetamine could potentially break through well-made handcuffs.
Another common method of escaping (or attempting to escape) from being handcuffed behind the back, is that one would, from a sitting or lying position, bring one's legs up as high upon one's torso as possible, then push one's arms down to bring the handcuffs below one's feet, finally pulling the handcuffs up using one's arms to the front of one's body. This can lead to awkward or painful positions depending on how the handcuffs were applied, and typically requires a good amount of flexibility. This maneuver, and the reverse (otherwise impossible) maneuver of bringing the handcuffed hands up behind the back and forwards over the head and then down in front, can be done fairly easily by some people who were born without collarbones because of the inherited deformity called cleidocranial dysostosis.
From this position, one has a better chance of attempting to use a tool (such as a shim or lockpick) to work one's way out of the handcuffs.
In Japan, if someone is photographed or filmed while handcuffed, their hands have to be pixelated if it is used on TV or in the newspapers. This is because someone who had been arrested brought a successful case to court arguing that being pictured in handcuffs implied guilt, and had prejudiced the trial.
Police handcuffs are sometimes used in sexual bondage and BDSM activities. This is potentially unsafe, because they were not designed for this purpose, and their use can result in nerve or other tissue damage; bondage cuffs were designed specifically for this application.
Handcuffs are familiar enough for the word to be used in metaphors, e.g.:-
* Golden handcuffs
* "He said that his computer work is handcuffed by his internet provider's refusal to accept .zip files."