1. Design of screw jack
Y. Mohan S S Ram

2. Screw jack
A screw jack is a portable device consisting of a screw mechanism used to raise or lower the load
Jack is simple and widely used device
They are 2 types of jacks
Hydraulic jack(cylinder and piston mechanism)
mechanical (hand operated)

3. Applications of screw jack
Paper, press, printing industry
Gypsum factories
Sheet metal forming machinery
Mechanical lifting applications
Platform lifting applications
Food processing machinery
Construction sector
Bridge jacks for road and bridge lifting
Shipyards
Opening and closing of penstocks 
Industrial process
Roll form machinery
Mining industry
Defence industry
Lift tables
Stage setup applications

4. In screw jack applications, the hazards are dropping, tipping or slipping of machines or their parts during the operation.
The main reasons
Jack is overloaded
Load is improperly secured on the jack
Jack not placed on hard and level surface
Jack is used for a purpose for which it is not designed
Proper size ,strength and stability are essential requirements for the design of the screw jack

5. Construction of screw jack
Name of component
material
Frame
Grey cast iron
Screw
Steel 30c8
Nut
Phosphor Bronze Grade-1
Handle
Cup
Set screw
Commercial steel
washer

10. Inner diameter(D1), Outer diameter(D2) and thickness of the nut collar

11. The cup fitted with a pin of diameter
Diameter of head
D3 = 1.75 do
The cup fitted with a pin of diameter
D4 = D3/4

14. Buckling