Motor sizing

Volume of the upper linkage(using aluminum channel) = (30 x 1.2 x 1.5 ) = 54 cm3

Volume of the toggle =[ (0.5 x 12 x 18 )-(0.5 x 8 x 10 )] + [0.5 x 9 x 3 ] = 81.5 cm3 x 2 = 163 cm3

Volume of the down linkage = [1 x 12 x 3 ] = 36 cm3

Volume of the piston= 288 cm3

Density of acrylic sheet = 1.18 g/cm3

Density of foamboard = 0.961 g/cm3

Density of aluminum channel = 2.70 g/cm3

Mass of the upper linkage= 54 x 2.70 = 145.8 g = 0.1458 kg

Mass of the toggle linkage(using acrylic sheet)= 163 x 1.18 = 192.34 g = 0.19234 kg

Mass of the down linkage = 36 x 1.18 = 42.48 g = 0.04248 kg

Mass of the toggle linkage(using foam board) = 163 x 0.961 = 156.643 g = 0.156643 kg

Mass of the piston= 288 x 0.961 = 276.768 g = 0.276768 kg

Total Mass= 0.19234 + 0.04248 + 0.156643 + 0.276768 + 0.1458 = 0.814031 kg

Spring constant(k)=F/x=Total mass/displacement

k = 0.814031 kg / 1.4 cm

k= 0.581450714 kg/cm

Torque= Total mass x radius = 0.814031 x 30 = 24.42093 kg-cm

Torque with spring= 24.42093 / 0.581450714 = 42 kg-cm

Due to this massive high torque, we are using 10rpm Jhonson DC motor.(120kg-cm)

Adapter sizing

Operating voltage for DC motor=12V

No. of Dc motor=1

Factor of safety=1.2

Operating Current = 1 x 300mA = 300mA x 1.2 = 360mA

Therefore,12V 1A Adapter is used.