Name: lifting tong force analysis
Uploaded: 2023-09-22T11:49:25.000Z
Duration: 1 min 30 s
Channel: JoVE

Consider a lifting tong carrying a 100 kg load. It comprises movable sections DAF and CBG linked together with member AB.
Assuming the structure is symmetrical about point E, what force is acting on member AB?
A free-body diagram indicating the forces acting at point E is drawn.
The cable&#39;s tension force balances the load&#39;s weight and acts vertically upwards.
ED and EC are two-force members. So, the forces FED and FEC are directed towards joints D and C, respectively.
These forces are resolved into horizontal and vertical components, and the structure&#39;s geometry is applied to determine the angle between the member ED and the horizontal force component.
Applying the force equilibrium condition along the horizontal direction ensures that FED equals FEC.
Similarly, the vertical force equilibrium condition yields the force along the member ED.
Now, consider a free-body diagram for section DAF. The moment equilibrium condition can be applied to joint F. 
Substituting all the known values into the equation gives the force along member AB.

machines: problem solving ii

Machines are complex structures consisting of movable, pin-connected multi-force members that work together to transmit forces. Consider a lifting tong carrying a 100 kg load. It comprises movable sections DAF and CBG linked together with member AB.
<img alt="Static equilibrium, ΣFx=0, ΣFy=0, mechanical diagram for weight lifting with linkage system." src="/files/ftp_upload/14295/14295_PT_Fig_1v2.svg" style="text-align: center; height: 350px;" data-altupdatedat="1761830439000" data-alt="Figure 1">
Assuming the structure is symmetrical at point E, the force acting on member AB can be calculated.
First, a free-body diagram indicating the forces acting at point E is considered. The weight of the load that equals the mass times the acceleration due to gravity is calculated as 981 N. The cable's tension force balances the load's weight and acts vertically upwards. ED and EC are two-force members. As a result, the forces FED and FEC are directed towards joints D and C, respectively.
Next, the forces FED and FEC are resolved into horizontal and vertical components. The structure's geometry can calculate the angle between the member ED and the horizontal force component as 30.96 degrees.
The force equilibrium conditions can be applied to joint E.
<img alt="Static equilibrium equation ΣFx=0, used in physics diagrams for force analysis." src="/files/ftp_upload/14295/14295_PT_Equation_1v2.svg" style="text-align: center; height: 13px;" data-altupdatedat="1761830439000" data-alt="Equation 1">
<img alt="Static equilibrium, ΣFy=0, equation for force balance analysis." src="/files/ftp_upload/14295/14295_PT_Equation_2v2.svg" style="text-align: center; height: 13px;" data-altupdatedat="1761830439000" data-alt="Equation 2">
Applying the force equilibrium condition along the horizontal direction ensures that FED equals FEC. Similarly, the vertical force equilibrium condition yields the force along the member ED as 953.46 N.
Now, a free-body diagram for section DAF is considered. The moment equilibrium condition can be applied to joint F.
<img alt="Static equilibrium concept, ΣMF=0, formula, equilibrium analysis, physics, mechanics." src="/files/ftp_upload/14295/14295_PT_Equation_3v2.svg" style="text-align: center; height: 13px;" data-altupdatedat="1761830439000" data-alt="Equation 3">
The result gives the force along member AB as 2423.76 N.
Understanding the forces acting on each member in this lifting tong system is essential for ensuring safe operation and designing efficient lifting mechanisms. By analyzing the forces and applying equilibrium conditions, engineers can optimize the structure and ensure it can safely carry loads under various conditions.

Machines: Problem Solving II

Machines are complex structures consisting of movable, pin-connected multi-force members that work together to transmit forces. Consider a lifting tong ...

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lifting tong force analysis

Lifting tong force analysis shows how forces move through a pin-connected machine. The structure uses movable sections DAF and CBG with member AB linking them together. Because these parts work as connected members, the load can be studied with equilibrium methods.

The example starts with a 100 kg load at point E. The load weight is found by multiplying mass by gravity, which gives 981 N. The cable tension acts upward and balances that weight. Since the structure is symmetrical at E, the forces on the two sides can be compared.

Members ED and EC are two-force members, so their forces act along the members toward joints D and C. Their forces are then split into horizontal and vertical parts. Using the geometry of the tong, the angle between member ED and the horizontal is 30.96 degrees. Force equilibrium at joint E shows that F ED equals F EC, and the vertical balance gives the force in member ED as 953.46 N.

After that, a free-body diagram for section DAF is used. The moment equilibrium condition is applied at joint F. This step gives the force in member AB as 2423.76 N. This kind of analysis helps engineers check the forces in each member so lifting systems can work safely and efficiently under load.

Lifting Tong Force Analysis

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Lifting tong force analysis shows how forces move through a pin-connected machine. The structure uses movable sections DAF and CBG with member AB linking them together. Because these parts work as connected members, the load can be studied with equilibrium methods. The example starts with a 100 kg load at point E. The load weight is found by multiplying mass by gravity, which gives 981 N. The cable tension acts upward and balances that weight. Since the structure is symmetrical at E, the...

key terms and concepts

Analyze a lifting tong with pin-connected members, symmetry, and equilibrium. See how force, tension, and moments determine the load on member AB.

Lifting Tong Force Analysis | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

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Lifting Tong Force Analysis

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