Rather than using cables or a hydraulic cylinder to move the elevator cab, this type of drive uses a chain (much like a very large bike chain) to transfer torque from the motor with a system of gears. One might think this would be really noisy, but it’s actually rather quiet – almost as quiet, in fact, as a hydraulic cylinder system.
Chains have a very significant maintenance advantage over cables: They don’t stretch as easily. Where cables need replacement every five years or even less, a well-maintained chain can easily last for twenty years without replacement.
Unlike winding drum or hydraulic systems, a chain-driven home elevator typically uses a counterweight – essentially a stack of steel blocks equaling the weight of a 40% loaded elevator cab, hung on the other end of the chain opposite the cab itself. This increases mechanical efficiency and also provides additional security against free-falling.
Considering all factors, we recommend chain drive for most home elevator systems. It’s relatively inexpensive, quiet, reliable, and low maintenance.