Wheelchair
The earliest records of wheeled furniture are an inscription found on a stone slate in China and a child's bed depicted in a frieze on a Greek vase, both dating between the 6th and 5th century BC.
[7] Although Europeans eventually developed a similar design, this method of transportation did not exist until 1595[8] when an unknown inventor from Spain built one for King Phillip II.
Although it was an elaborate chair having both armrests and leg rests, the design still had shortcomings since it did not feature an efficient propulsion mechanism and thus required assistance to propel it.
[4] In 1655, Stephan Farffler, a 22-year-old paraplegic watchmaker, built the world's first self-propelling chair on a three-wheel chassis using a system of cranks and cogwheels.
[4] A self-propelled wheelchair was made for the Parliamentarian commander-in-chief Sir Thomas Fairfax due to the many injuries he had received during the English Civil War, and he used it during the final years of his life.
Soon, many healthy tourists also rented the decorated "rolling chairs" and servants to push them as a show of decadence and treatment they could never experience at home.
[12] In 1933 Harry C. Jennings Sr. and his disabled friend Herbert Everest, both mechanical engineers, invented the first lightweight, steel, folding, portable wheelchair.
This allows for more mechanically efficient propulsion by the user and also makes it easier to hold a straight line while moving across a slope.
The wheelie allows an independent wheelchair user to climb and descend curbs and move more easily over small obstacles and irregular ground such as cobbles.
Various optional accessories are available, such as anti-tip bars or wheels, safety belts, adjustable backrests, tilt and/or recline features, extra support for limbs or head and neck, holders for crutches, walkers or oxygen tanks, drink holders, and mud and wheel-guards as clothing protectors.
Powerchairs have access to the full range of wheelchair options, including ones that are difficult to provide in an unpowered manual chair, but have the disadvantage of significant extra weight.
A floating rim design senses the pressure applied by the user's push and activates the motors proportionately to provide a power assist.
This results in the convenience, and small size of a manual chair while providing motorised assistance for rough/uneven terrain and steep slopes that would otherwise be difficult or impossible to navigate, especially by those with limited upper-body function.
Mobility scooters share some features with powerchairs, but primarily address a different market segment, people with a limited ability to walk, but who might not otherwise consider themselves disabled.
Smaller mobility scooters are typically three wheeled, with a base on which is mounted a basic seat at the rear, with a control tiller at the front.
Some wheelchairs, designed for use by hemiplegics, provide a similar function by linking both wheels rigidly together and using one of the footplates to control steering via a linkage to the front caster.
The original concept was developed by an orthotist, Hugh Barclay, who worked with disabled children and observed that postural deformities such as scoliosis could be supported or partially corrected by allowing the wheelchair user to relax in a tilted position.
Reclining wheelchairs are preferred in some cases for some medical purposes, such as reducing the risk of pressure sores, providing passive movement of hip and knee joints, and making it easier to perform some nursing procedures, such as intermittent catheterization to empty the bladder and transfers to beds, and also for personal reasons, such as people who like using an attached tray.
[17] Tilting wheelchairs are preferred for people who use molded or contoured seats, who need to maintain a particular posture, who adversely affected by sheer forces (reclining causes the body to slide slightly every time), or who need to keep a communication device, powered wheelchair controls, or other attached device in the same relative position throughout the day.
They are usually non-folding (in order to increase rigidity), with a pronounced negative camber for the wheels (which provides stability and is helpful for making sharp turns), and often are made of composite, lightweight materials.
The common adaptation among the different designs is that they have extra-wide balloon wheels or tires, to increase stability and decrease ground pressure on uneven or unsteady terrain.
Others focus on users living with severe motor disabilities, such as cerebral palsy, or with quadriplegia, and the role of the smart wheelchair is to interpret small muscular activations as high-level commands and execute them.
Engineering modifications have added hand-controlled levers to the LFC, to enable users to move the chair over uneven ground and minor obstacles, such as bumpy dirt roads, that are common in developing countries.
The two-gear wheels offer two speed ratios- 1:1 (no help, no extra torque) and 2:1, providing 100% more hill climbing force.
That makes long-distance journeys and everyday tasks much easier and keeps wheelchair users hands clean.
Access needs for people with other disabilities, for instance visual impairments, may also be required, such as by provision of high visibility markings on the edges of steps and braille labelling.
Accessible bathrooms can permit the use of mobile shower chairs or transfer benches to facilitate bathing for people with disabilities.
Modern architecture is increasingly required by law and recognised good practise to incorporate better accessibility at the design stage.
These may range from keeping a portable ramp on hand to allow a wheelchair user to cross an inaccessible threshold, to providing personal service to access goods they are not otherwise able to reach.
[34] For someone in the sitting position, the parts of the body that are the most at risk for tissue breakdown include the ischial tuberosities, coccyx, sacrum and greater trochanters.
