Travelling Nut Screw Jack with Safety Nut

Travelling Nut Screw Jack with Safety Nut is also as known Wear-indicator Nuts Screw Jacks. One concern when designing a lifting systems based on screw jacks is how to know if the travel nut (which bears the load) is worn out or about to fail, especially when the lift operates in a place where personnel might get hurt if the mechanism fails. In these machines, a safety nut assembly (sometimes called a wear-indicator nut) can mount vertically with the load in a downward direction to leverage newton's law of gravity. In other words, wear-indicator nuts work where the load is above the nut assembly.

As the primary (load-bearing) travel nut traverses the load, it wears … and its threads get thinner. Eventually, the thread won't be able to bear the machine load and will fail. To prevent this from happening without warning, wear-indicator nuts travel with the primary nut. As this nut's internal threads thin, it will exhibit an increasing amount of play and the gap between it and the follower wear-indicator nut becomes smaller. This narrowing gap indicates the amount of wear on the thread. To be clear, the follower wear-indicator nut usually bears no load; it's merely twinned to the primary nut to follow along.

Requirement for increased operating safety. To limit material damage in event of nut breaking. Supporting nut with short safety nut for visual wear monitoring. Requirement for personal safety measures and/or conformity to accident-prevention standards (persons under raised load/working platforms). In the case of worm gear screw jacks used on theatre stages (lifting platforms or jacking systems that might affect personal safety, lifting elements are designed according to current regulations, and include such items as anti-drop systems (self-locking spindles and/or mechanical safety brakes as part of the drive system). The function of the synchronizing device is guaranteed, when required, by additional components.