There are three drive mechanisms being utilized in the stair lift industry today. There is a Winch Design (SL350 by Harmar) where the loose end of the cable is secured to the top of the track. As the cable unwinds from the drum, gravity allows the chair to roll down the track. When the cable is wound back onto the drum, the chair rises to the top. Fairly simple design, but will require greasing the track every 90-120 days.
All manufacturers offer a Rack-and-Pinion drive system. This is nothing more than a long toothed “rack” gear that runs the entire length of the track. A round “pinion” gear then runs up and down the “rack” gear. These systems will require regular (90-120 day) cleaning and greasing as well.
There is only one design that uses a “Grease Free” Worm Drive. This patented technology consists of a large nylon worm (think of it as a threaded screw) that threads itself up and down the track. This is the quietest and smoothest system there is. Most important – it NEVER needs to be greased. There are two versions of this design. One of these models folds up to 10.5 inches (the narrowest in the industry) and is commonly used on narrow staircases or for those simply desiring more useable staircase. The less expensive and very popular standard unit folds to 13.5 inches and still provides ample space for those walking the steps.
If you keep adding grease … where does it eventually end up? Exactly, it could easily end up on your carpets, floors, walls, and grandkids hands. Here are some comments taken from the web concerning proper maintenance of the rack-and-pinion stair lifts requiring grease. These maintenance requirements are from two major manufacturers of stair lifts. Don’t get caught in the “Grease Trap”.
“Keeping your stairlift clean is a simple yet effective way to maintain its life span. Get a duster or damp cloth and wipe over the track and seat at least once a week to prevent a buildup of dust and dirt. Avoid the use of solvents and detergents, as these can be abrasive. Instead, choose a damp soapy cloth for best results.
Over time your stairlift can become stiff, so occasional lubrication can prevent deterioration in its movement. Apply a small amount of Vaseline or other lubricant to the track and any moving parts to keep them well oiled. It’s important that you do this after the cleaning process, so remove any dirt beforehand.”
“Periodic lubrication of the stairlift rack and teeth will make for a smooth, comfortable ride every time. Spray a thin coat of white lithium grease on the gear rack teeth of the stairlift, located on the wall side of the rail. The lithium grease includes a nozzle which enables pinpoint spraying of the lubricant. Aim the nozzle at the gear rack teeth and spray some lubricant out. Careful to apply only a light coating to the gear rack teeth. If any of the stairlift’s belts appear dry, apply a light coating of the same lithium grease across the belt’s surface.”