The positive properties of the worm gear drive in terms of self-locking, quiet running, and problem-free transmission of impact-type movements were the deciding criteria for the selection of this type of power transmission.
The drive occurs by means of a Walther Flender worm gear drive of type I including a permanent magnet DC brake motor of 24 Volt and a brake in a special design. The brake motor has a second shaft end for emergency operation. The travel speed is max. 0.15 m/s, and the speed reduces steplessly when travelling curves. The stair lifts can stop at any floor and they halt exactly at the level of the final step of the stairs. Here, control is achieved via current rectifiers. If there is a power outage, the system is made safe by the self-locking worm drive, the brake motor and the catching device. Because of additional devices such as the motor with the second shaft end, a manual brake ventilation device and a hand crank, the lift can be moved manually by the user.
In addition to the high qualitative and safety technology requirements, the functionality, design, and styling play a significant role. The worm gear drives have been developed on the modular principle, taking into account user-friendly construction styles and dimensions. The combined drive unit is especially space-saving, and fulfils the user’s expectations in terms of economy, solidity, compactness of construction, precision, and long working life.