# LEAD SCREW CALCULATION FORMULA

 Parameter Equation Torque required to raise the load [TR] 1,2,3 $${ T }_{ R }=\frac { F\cdot { d }_{ m } }{ 2 } (\frac { l+\pi f{ d }_{ m }\sec { \alpha } }{ \pi { d }_{ m }-fl\sec { \alpha } } )+{ T }_{ c }$$ Torque required to lower the load [TL]1,2,3 $${ T }_{ R }=\frac { F\cdot { d }_{ m } }{ 2 } (\frac { -l+\pi f{ d }_{ m }\sec { \alpha } }{ \pi { d }_{ m }+fl\sec { \alpha } } )+{ T }_{ c }$$ Frictional torque of the thrust collar [Tc] $${ T }_{ c }=\frac { F{ f }_{ c }{ d }_{ c } }{ 2 }$$ Efficiency during lifting the load [e] 3 $$e=\frac { Fl }{ 2\pi { T }_{ R } }$$