Sharing the Knowledge: Incline and Vertical Platform Liftsby David Barlew, Jr. on 09/26/11
Last Wednesday, I attended an excellent and very informative continuing education seminar on the two primary types of wheelchair platform lifts: incline platform lifts and vertical platform lifts.
Incline platform lifts transport wheelchair users up and/or down stairs in both indoor and outdoor applications. I was surprised to learn that these lifts are not limited to straight runs of stairs; rather, these lifts have the capability of running up and down multistory staircases with multiple turns and landings. The only constraint is that the stair must be at least four feet wide. To go up and down stairs, the lifts run along two sets of tubular metal guides mounted on the inside or outside radius of the stair. As I understand it, the lifts look kind of like this is plan view:
In my very simple sketch, the thick, solid, curving line represents the guides along which the wheelchair platform moves. It is typically necessary to remove the existing handrails in order to install the tubular guide rails for the lift system. Following installation, new handrails can be installed at code-prescribed height and with code-prescribed rail diameter. During the seminar, I thought that the tubular metal guides and platform together looked sort of like a slow-motion amusement park ride. Unlike amusement park rides, however, the lifts' platforms slow down when making the turns at landings. The platforms also stop at each landing to give the rider an opportunity to get off.
To use an incline platform lift, the rider activates one of the lift's call stations, which are located at each landing. As the arrival of the lift may take some time, it is best if the lift is installed on a stair in such a way that the person using the lift can get on and off the lift without people in their way and without being in the way of other people. Once the platform arrives, the rider then places himself on the platform. I need to note that, while these lifts are intended primarily for wheelchair users, they are also equipped with a seat for ambulatory people who are unable to go up and down stairs. Once onboard, the rider presses and holds the "go" button to make the platform move. Unlike elevators, incline platform lifts only work while the "go" button is being pressed; they are not automatic. The lift's passenger then rides to the level of his choosing. After getting off of the lift, the person can either manually or automatically "park" the unit out of the way.
In order to move the platform and the passenger onboard, an incline platform lift is powered by a drive system installed at one end of the lift's route along the stairs. The drive system can be located in-line with the lift, offset from the lift, or installed ninety degrees from the direction of the lift. Although incline platform lifts can be powered by either a standard drive system or a compact drive system, the compact drive system is not recommended unless absolutely necessary.
I was happy to see that incline platform lifts are loaded with safety features. First, all lifts have an emergency stop switch. But, since the "go" buttons must be held at all times in order to move the unit, the units will stop anyway if the button is not held. Other safety features include ramp and under-platform sensing devices to keep the unit from driving over objects left on the stairs; bidirectional ramp sensing to keep the unit from driving over pedestrians on the stairs; pedestrian safety lights to warn pedestrians on the stair of the unit's approach; and wall mounted audio-visual alerts to inform the passenger of any issues.
Vertical platform lifts are the other type of lift used to transport wheelchair users from one level to another whether inside or outside. The first question, of course, is "Why not just install an elevator?" The reason, we were told, is that vertical platform lifts typically cost much less than an elevator and also lack machine rooms, which gobble up extra square footage. So, what's the catch? Vertical platform lifts are intended only for very occasional use. If the unit will be used frequently or regularly, an elevator is recommended.
For best results, vertical platform lifts should be operated by hydraulics rather than lead (pronounced like the verb, not the metal) screws because lead screws tend to be noisy and very slow. Hydraulics, on the other hand, tend to be smoother and offer a better ride. Unfortunately, though, both are slow: hydraulics go at seventeen vertical feet per minute, and lead screws go at twelve vertical feet per minute.
As with incline platform lifts, vertical platform lifts are also loaded with safety features. Most importantly, the doors on a vertical platform lift will not open while the unit is in use. Other safety features include an emergency stop button; emergency manual lowering; an auxiliary power system; an emergency alarm; emergency lighting; and electric mechanical locks.
Vertical platform lifts are manufactured in three primary configurations: straight through, on/off same side, and 90 degree.
David Barlew Architects actually incorporated two vertical platform lifts into our design for the Auditorium Building Renovation and Addition at
Tolar, John. "
Written by David Barlew, Jr. for David Barlew Architects, Inc.
All drawings by David Barlew, Jr.