The object of this thesis is the design and calculation of the central elements of machinery and drive screws of a scissor lifting machine. The machine consists of two pairs of legs which are connected to each other in a transverse position by means of a pin, on which the loading plate rests. Each support leg has a fixed and a movable end. The movement of movable limbs occurs through swivel wheels. Lifting the load is achieved by pushing the outer legs by a drive screw, which is driven by an electric motor. The construction rests firmly on the floor on two horizontal guides. The load lifting capacity is 10000 kg (10 tons).
A full-dimensional lifting platform with the following characteristics is required.
• Lifting mass W=10 tn
• Beam length L=1,8m
• Minimum angle at bottom position θ=15 degrees
• Maximum lifting height 3m
• Number of scissors equal to 3
The following should be calculated:
• The maximum angle θmax in the upper position.
• Dimensions of the beam of square cross-section according to Figure 1 for a maximum bending stress of less than 100 MPa. For convenience, the wall thickness t should be taken equal to 5 mm. Choose the appropriate material to optimize the weight/load ratio.
• Size the pin in position A (diameter calculation) according to Figure 2 for a maximum shear stress equal to 75 MPa.
• The maximum and minimum working pressure of the horizontal cylinder (positions B-C) if the diameter D = 150 mm and the diameter of the support d = 75 mm are known.
you will also need drawings in cad, solid models and 2D drawings
As well as the FEA analysis logically.
