helical spring

conical spring

flat spiral spring

volute spring

friction angle is less than helix angle

friction angle is more than helix angle

friction angle is equal to helix angle

efficiency of screw is 100%

introduce mechanical flexibility

introduce protection against overloads

reduce the transmission of shock loads

all of these

which are perfectly aligned

which are not in exact alignment

which have lateral misalignment

whose axes intersect at a small angle

obtain variable moment of inertia (I) in each leaf

permit each leaf to act as a overhanging beam

have variable bending moment (M) in each leaf

make M/I constant throughout the length of the leaf