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, you need to use the following steps:
1. Calculate the equivalent force applied on Toggle 2 (T2):
Multiply the length of T2 (0.445m) by the force applied on it (300.557N):
T2 = 0.445m * 300.557N = 133.748N
2. Assume Toggle 1 (T1) is lifting the entire load. Calculate the velocity ratio of the screw jack:
Velocity Ratio (V.R.) = Circumference of leverage / pitch of the thread
V.R. = 2π * 0.52m / 0.013m = 251.3
3. Calculate the efficiency of the screw jack:
Efficiency = Mechanical Advantage / V.R.
Efficiency = 0.35 * 251.3 = 87.955
4. Calculate the total load lifted by the screw jack:
Mechanical Advantage (M.A.) = Load / Effort
Load = M.A. * (Force applied on T1 + Force applied on T2)
Load = 87.955 * (230N + 257.2N) = 42851.8N
5. Convert the load to tonnes:
Load in kg = 42851.8N / 9.81m/s²
Load in tonnes = Load in kg / 1000
Load = 4.373 tonnes
Therefore, the load that can be lifted by the screw jack is 4.373 tonnes.
To calculate the load that can be lifted by the screw jack, we can use the following steps:
1. Calculate the equivalent force applied on Toggle 2:
Force applied on Toggle 2 = Toggle 2 length * Force applied
Force applied on Toggle 2 = 0.445m * 300.557N
Force applied on Toggle 2 = 133.748N
2. Assuming Toggle 1 length to be 520mm, calculate the equivalent force on Toggle 1:
Force on Toggle 1 = Force applied on Toggle 2 * (Toggle 2 length / Toggle 1 length)
Force on Toggle 1 = 133.748N * (0.445m / 0.52m)
Force on Toggle 1 = 257.2N
3. Calculate the Velocity Ratio (V.R.) of the screw jack:
V.R. = Circumference of leverage / pitch of thread
V.R. = (2π * 0.52) / 0.013
V.R. = 251.3
4. Calculate the efficiency of the screw jack:
Efficiency = Mechanical advantage / V.R.
Efficiency = 0.35 * 251.3
Efficiency = 87.955
5. Calculate the load lifted by the screw jack:
Load = Mechanical advantage * (Force on Toggle 1 + Force on Toggle 2)
Load = 87.955 * (230N + 257.2N)
6. Convert the load from N to tonnes:
Load = Load / 9.81 (gravity)
Load = 42851.8N / 9.81
Load = 4372.62kg / 1000
Load = 4.373 tonnes
Therefore, the screw jack can lift a load of 4.373 tonnes.