DESIGN OF TOGGLE JACK CONSIDERING MATERIAL SELECTION OF SCERW - NUT COMBINATION

Abstract

Toggle jacks are simple mechanisms used to drive large loads short distances and to lift the heavy loads. It also have the advanced feature of rotating the parts about their axis where there is not enough space to move the load. The power screw design of a common Toggle jack reduces the amount of force required by the user to drive the mechanism. Most of the Toggle jacks are similar in design, consisting of eight main members out of whom four are driven by a power screw and rest of four by loading condition. In this report, a unique design of a Toggle jack is used to lift the heavy loads at the stable state with the unique condition. In toggle jack screw and nut are main components. A screw is moving part and nut is a stationary part. Both the parts always work in meshing condition. Therefore there are stresses like shear and tensile stresses induced in materials which are responsible for failure of screw. While a nut has bearing stress. Different materials of screw and nut can induce different magnitude of stresses so it is necessary to select a pair of material combination in such a way that a pair gives induced stress within safe limit. Here we have taken different material combinations of screw and nut & based on that analytical design is done for on different loading condition from 1KN to 5KN. It is also assumed that the nominal diameter of screw and material for link are same for all loads.