Lead And Jack Screw

This Jack Screw is a type of jack that is operated by turning a lead screw. Jack Screw it is commonly used to lift moderately heavy weights, More commonly it is used as an adjustable support for heavy loads, such as the foundations of Steel Plants, or Construction (Bridges). The mechanical advantage of a screw jack, the ratio of the force the jack exerts on the load to the input force on the lever, ignoring friction. This derives from two factors, the simple lever advantage of a long operating handle and also the advantage of the plane of the lead screw. Screw jacks are limited in their lifting capacity. Increasing load increases friction within the screw threads. A fine pitch thread, which would increase the advantage of the screw, also reduces the size and strength of the threads. Longer operating levers soon reach a point where the lever will simply bend at their inner end.