What load can be lifted by a screw jack given:
Toggle1 length:520mm
Force applied:230N
Toggle2 lenght:445mm
Force applied:300.557N
Mean pitch of thread:13mm
S.J. efficiency:35%
My answer:
Assuming T2 to be 520mm long, the equivalent force would be:
0.445mX300.557N=0.52m X F2
F2=133.748/0.52
F2=257.2N
Assuming T1 as lifting the entire load:
Velocity Ratio of SJ=Circ of leverage/pitch of thread
V.R.=2pi0.52/0.013
V.R.=251.3
then:
Efficiency=Mech. adantage/V.R.
M.A.=251.3X0.35
M.A.=87.955
The load lifted by the Jack is:
M.A.=Load/effort
Load lifted=M.A.*(F1+F2)
Load=87.955*(230+257.2)
Load=42851.8/9.81
Load=4372.62kg/1000
Load=4.373tonnes
To calculate the load that can be lifted by a screw jack, we need to consider the toggle lengths, forces applied, mean pitch of the thread, and the screw jack efficiency.
First, let's calculate the equivalent force, F2, applied on toggle 2:
Toggle 2 Length (T2) = 445mm
Force applied on toggle 2 = 300.557N
Equivalent force on toggle 1 (F1) = Toggle 2 Length (T2) * Force applied on toggle 2 / Toggle 1 Length (T1)
Equivalent force on toggle 1 (F1) = 0.445m * 300.557N / 0.52m
Equivalent force on toggle 1 (F1) = 257.2N
Next, let's calculate the Velocity Ratio (V.R.) of the screw jack:
Velocity Ratio (V.R.) = Circumference of leverage / Pitch of thread
V.R. = 2 * π * 0.52m / 0.013m
V.R. = 251.3
Now, let's calculate the mechanical advantage (M.A.) of the screw jack:
Efficiency = Mechanical Advantage (M.A.) / Velocity Ratio (V.R.)
Mechanical Advantage (M.A.) = Efficiency * Velocity Ratio (V.R.)
Mechanical Advantage (M.A.) = 0.35 * 251.3
Mechanical Advantage (M.A.) = 87.955
Finally, we can calculate the load that can be lifted by the screw jack:
Load = Mechanical Advantage (M.A.) * (Force applied on toggle 1 + Force applied on toggle 2)
Load = 87.955 * (230N + 257.2N)
Load = 42851.8N
To convert the load from Newtons to kilograms:
Load (kg) = Load (N) / 9.81 m/s^2
Load (kg) = 42851.8N / 9.81 kg/m/s^2
Load (kg) = 4372.62kg
To convert the load from kilograms to tonnes:
Load (tonnes) = Load (kg) / 1000
Load (tonnes) = 4.373 tonnes
Therefore, the load that can be lifted by the screw jack is approximately 4.373 tonnes.