Standard Worm Gearboxes

Self-locking property of Worm Gearboxes

A precondition for the self-locking quality of gearboxes is a small tooth lead angle of the worm and thus an efficiency of η ≤ 0,5 with worm driving. Consequently self-locking gearboxes are generally uneconomical when high performances and long operating times are required. A worm gearbox is considered self-locking at standstill if, with worm wheel driving, starting from standstill is impossible. This is the case with ATLANTA wheel sets and gearboxes when the lead angle is <5°. A worm gearbox is considered self-locking from the running condition if the gearboxes comes to a standstill whilst being backdriven. This is only possible with high gear ratios and very low speeds. Shocks and vibrations can neutralize the self-locking capacity! Therefore a self-locking tooth system cannot replace a brake or reverse-stroke locking mechanism. In order to avoid overstressing of the worm gear drive due to the very high kinetic energy involved, you should furthermore allow for a certain running-down time after stopping the input.