The assistive devices known as stairlifts don't have a long history, but consistent technological advances in stairlifts have assured that they will have a bright future during the 21st century.
Believe it or not, the history of stairlifts is not that long.
They have only been around since the 1930s when the Inclinator Company of America introduced them.
Many of the earliest users were disabled by the polio epidemics of that time and couldn't climb stairs easily.
  Interestingly enough, the earliest ancestor of the stairlift device was created centuries ago for King Henry VIII, who, after being injured in a jousting incident, used a block and tackle system operated by servants to go up and down stairs.
Modern stairlifts don't require a large staff of servants or any block and tackle to operate, however.
A stairlift consists of a rail mounted along a stairwell or staircase with a chair or lifting platform attached to it.
The person using it simply folds down the chair, sits, and then operates the controls for a smooth gentle ascent of the staircase.
  The history of stairlifts includes many technological innovations and the addition of a variety of features to make them safer, more comfortable and easier to use.
For instance, modern chair lifts feature adjustable seat height, swiveling seats, isolation switches, folding steps, armrests, speed governors, seatbelts, and so-called soft starts and soft stops.
Stairlifts either run on a straight rail or a curved rail depending on the shape of the staircase where they're installed.
These devices can also be installed on either the right or left side of a stairway.
However, it should be noted that curved rail stairlifts are generally more expensive than the simpler straight rail models because of the added expense of measuring and fitting the rails to curved surfaces that often vary widely in length and the angle of the curve.
  The history of stairlifts also includes the invention of outdoor stairlifts.
These are similar in design and function to indoor stairlifts, but of course must be made weatherproofed so that water and dust don't get inside the housing for the electric motor that powers the device.
Outdoor stairlifts also generally come with removable covers for so that they don't become too sun-damaged, rain-soaked, or weather-beaten to be comfortable for the user.
  One of the most interesting innovations in the history of stairlifts is the battery-powered stairlift that includes a battery between the power outlet and the stairlift's motor.
These are handy for areas that are prone to power outages because the battery provides power to the motor even when there is no electricity in other areas of the home.
Battery-powered stair lifts are generally more expensive than models that plug directly into an AC power outlet and have the disadvantage of having to replace the batteries periodically.
There are also heavy-duty stairlifts available that can support people who weigh up to 500 pounds.
Since it appears that America's population is growing bulkier, these heavy-duty stairlifts will undoubtedly become more popular, and models that can support even larger people will come onto the market.
  The demand for stairlifts will likely skyrocket as America's population ages and more people live to advanced ages in the coming decades.
There's no doubt that technological advances will continue to play a large role in this industry as new, more powerful, more efficient motors will be installed that last longer and consume far less energy.
Even if new high-tech wheelchairs that can climb stairs become a lot cheaper and more readily available, it seems there will always be a market for stairlifts [http://www.
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com/stairlifts/] in stairways that are too narrow and curved to accommodate such wheelchairs.