A double screw (Acme thread angle φ = 14.5ͦ ) mechanism is designed to lift a load of 44,000 lb in such a way that scre
Posted: Tue Jul 12, 2022 8:49 am
A double screw (Acme thread angle φ =14.5ͦ ) mechanism is designed to lift a load of44,000 lb in such a way that screw is loaded intension. Use of Safe Factor of safety of 1.8.Select a suitable screw from data table provided in class notes fortensile load and shear load. Limiting tensile and shear stressesare 10,000 psi and 5,500 psi, respectively.Required thickness of Yoke which functions as a nut. It is desiredto raise the hatch a total of 30.0 inches in 15 seconds. Usecoefficient of friction f = 0.15. Listnecessary assumptions. Sketch and Label a schematic diagram.DetermineNominal major diameter of screw (D)Threads per Inch of selected thread (n)Thickness of Yoke (h)Lead angle (λ)Torque required to raise the load (Tup)Torque required to lower the load (Tdown)Efficiency of the screwRPM required to operate each screwCompute the Total Power required to operate themechanism.