Types of Wheelchairs
The range of wheelchairs reflects the demand to meet individual needs.
Manual wheelchairs are those moved by the user or an attendant. The self-propelled chairs usually have rear wheels of between 20 and 26 inches in diameter fixed to an axle and positioned so that users can move them by pushing down or pulling back the push rims. The users can therefore travel forward and backward at speeds dictated by the amount of force they are able to apply.
By controlling the push rims, users can also turn left or right and negotiate small dips and rises that lie ahead. To operate manual wheelchairs successfully, however, users must have a good standard of muscular ability and coordination in their arms and shoulders.
Alternative methods of propulsion include foot pedals and levers worked by hand.
Manual Transit wheelchairs
Manual transit chairs generally have small rear wheels without push rims. These wheelchairs are most likely to be seen in buildings such as airports and hospitals where porters act as attendants. These are also called manual transfer chairs.
Power (Electric) Wheelchairs are also called “motorized wheelchairs” and sometimes abbreviated EPW (electric powered wheelchairs). Powered by an electric motor, these chairs are navigated by controls systems. Individuals too weak to maneuver a manually powered or standard wheelchair benefit from power chairs, as do individuals with heart and/or breathing conditions. Power electric wheelchairs are intended for use in everyday life and there are power wheelchairs made specifically for indoor and outdoor use.
Electric powered wheelchairs are ideal for anyone who does not possess the strength or ability to cope with a manual chair. Rechargeable batteries mounted under the seat supply power to electric motors that drive either two or all four of the wheels. As with a car, the different drive arrangements determine the way that the wheelchair moves and manoeuvres. It is important to know for what conditions a chair is designed for. Using indoor electric wheelchair outdoors runs the risk of potential damage to the frame, front forks, and motor could occur. The wheelchair industry has standards for brake efficiency, energy efficiency, overall size, speed and acceleration, impact testing, obstacle maneuverability, and control system ergonomics.
The batteries come in three types: wet-cell, gel-cell and AGM (absorbed glass mat).
- Wet-cell batteries are the lightest, cheapest and least likely to be overcharged. They tend to leak, however, so cannot be taken on a plane.
- Gel-cell batteries are heavier but do not leak. They last longer than wet-cell batteries and are accepted for air travel.
- AGM batteries are heavy and expensive, but they are suitable for airplanes, are shock-resistant and leak-proof, and do not require maintenance.
The above batteries may have to be charged by a separate unit, but most modern electric wheelchairs can simply be plugged into an electric socket.
Apart from the choice of batteries, there are options for managing the direction and speed of electric wheelchairs. Many have a small joystick that is mounted at the end of an arm rest or on a bar that swings in front of the user once he or she is seated. Others have tubes into which the users blow or suck to control the chair’s movements.
The level of disability experienced by electric wheelchair owners is also reflected in the design of other features. These include
- tilting mechanisms;
- reclining backs;
- seat, leg and arm elevators.
Most of these functions are controlled by small electric motors and allow users to make themselves as comfortable in the chair as possible. More on power vs. manual chairs.
A wheelbase chair, otherwise known as a scooter, has four small wheels extending from a low platform. The type of chair mounted on this platform varies according to the disability and needs of the user; some are even molded from a cast taken of the user’s most appropriate sitting position.
One of the advantages of the wheelbase machine is that the chair can swivel and allow the user to mount and dismount from either side. A disadvantage is that the user must maintain a rigid posture when driving. This means that wheelbase chairs are rarely suitable for the severely disabled.
The controls of the wheelbase chair are mounted on a frame that curves upward from the front of the platform to a height and position convenient for the user. A horizontal steering bar is attached across the top of the frame.
Since the 1970s, disabled athletes have had an increasing array of specialized wheelchairs to help them achieve the most from their chosen sport. These chairs can look very different from each other, but what they usually have in common is
- lightweight frames made from composite material;
- solidity (which means that they do not fold); and
- enhanced stability for sudden turns (this is achieved by using angled wheels).
Sports wheelchairs or recreation wheelchairs are specially designed for athletes with disabilities who are competing in sports that require agility and speed such as basketball, tennis, rugby or racing. These very specific chairs usually do not fold and are not used in everyday life. Depending on the sport, the chairs vary in design. The handcycle replaces the conventional bicycle with hand-powered peddles instead of leg powered peddles. Court chairs come with a variety of features including: front bumpers, wings, spoke protectors, castor protectors, adjustable trick footrests, and more. Racing chairs are for exactly that, racing! Their sleek designs allow competitors to rush across the finish line. All terrain wheelchairs enable exploration of off-road, unpaved, bumpy, gravel areas. The size truly depends on the sport. There are many modifications and adjustable features on this type of wheelchair. Sports wheelchairs are made from lightweight metals in order for the occupant to power it quickly and easily. Materials such as carbon steel frames, adjustable footrests, adjustable tension upholstery, aluminum pushrims, stainless steel or titanium axles are features of these very specific wheelchairs. More on wheelchair sports.
Stand-up wheelchairs are fitted with a hydraulic pump that lifts and tilts the seat, thereby enabling the user to "stand up" and yet be fully supported. This is an invaluable feature if the user needs to reach an item on a shelf either at home or while out shopping. Related: commode wheelchairs.
Climbing stairs is the ultimate test for a wheelchair, and there are a number of solutions available.
- Battery-operated supports at the back that act as stabilisers as the chair climbs.
- A series of flexible wheels turning within rubber tracks that grip the steps.
- Independent stair-climbing wheelbases onto which the wheelchair is fastened.
Most stair-climbing chairs do still need a third party attendant. Alternatively, the wheelchair user must be able to grasp a suitable handrail. The iBot made a lot of headlines a few years ago, but it is no longer sold.
A beach wheelchair is immediately recognizable because of its broad wheels that enable it to ride smoothly over sand without sinking. Some beach resorts now provide not only wheelchair accessibility but also offer beach wheelchairs to disabled clients.
Conventional wheelchairs will not safely bear a weight greater than 250 lbs. A bariatric wheelchair, however, can accommodate someone as heavy as 1000 lbs. The weight capacity of bariatric chairs, and the seat measurements, vary and are displayed on the promotional literature.
Pediatric wheelchairs are designed for disabled children. The chairs are not just smaller than the conventional equivalent; they can in some instances be adjusted to give children maximum freedom to sit, recline, and lie right back.
Snow wheelchair, from http://www.flickr.com/photos/8127509@N04/2333036875
from Flickr user mediadeo. Used under Creative