The History and Science of Stairlifts
Part 2 - Stairlift Features
Modern stair lifts can be found with a wide variety of features such as adjustable seat height, battery isolation switches, call stations, 'flip-up' rail, key switch, folding step, speed governor, seatbelt, soft start and soft stop.
Rails
Straight rails for use on domestic staircases are usually made from extruded steel and come in various cross-sectional shapes. These rails may, typically, weigh over 30 kg, depending on the length. In most applications they are attached to the steps with metal brackets (sometimes called “cleats”). If a rail crosses a doorway at the bottom of the stairs or causes an obstruction a hinge can be fitted so the end of the rail can be folded back out of the way when not in use.
Curved rails are also made from steel and come in various cross-sectional shapes according to the designer. Individual designs vary a lot and probably the key criterion is to make the curves with the smallest radius possible so they will wrap tightly around objects such as newel posts. The sections of curved rails are usually packaged well to prevent damage in transit and are unwrapped and assembled on site. Rails for wheelchair platform stairlifts may be secured to walls in addition to the step fixings.
Carriages
The carriage is the component which moves along the rail and normally runs on small diameter rollers. In most designs the carriage is driven along the inclined rail by a rack and pinion system.. Most domestic carriages have a seat with arms and a footrest. Some special models have a stand-on platform also known as a "perch" seat. For users with shorter legs a short seat can be fitted, to make the lift more comfortable to sit on. Stairlift manufacturer such as Minivator Ltd have a number of different seat types depending on individual needs.
The conventional layout for a typical domestic stairlift is to have the seat at right angles to the rail so the user travels "sidesaddle". At the top of the staircase the seat can be swivelled, commonly through around 45 degrees or 90 degrees, then locked in place to allow the user to alight from it onto a landing. Stairlifts are available with either a manual swivel or a powered swivel, depending on the user’s ability. Most swivel seats have a safety switch so the stairlift won’t move unless the seat is locked into its travel position. Special models with seats facing the bottom of the staircase have been produced for users with spinal or other conditions which prevent use of the conventional seat layout. More room is need on the landing with these special seats.
