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

Stellen Sie sich eine Hebezange vor, die eine Last von 100 kg trägt. Er besteht aus beweglichen Sektionen DAF und CBG, die mit dem Glied AB verbunden sind.
Angenommen, die Struktur ist symmetrisch um den Punkt E, welche Kraft wirkt auf das Element AB?
Es wird ein Freikörperdiagramm gezeichnet, das die am Punkt E wirkenden Kräfte angibt.
Die Zugkraft des Seils gleicht das Gewicht der Last aus und wirkt senkrecht nach oben.
ED und EC sind Mitglieder mit zwei Kräften. Die Kräfte FED und FEC sind also auf die Gelenke D bzw. C gerichtet.
Diese Kräfte werden in horizontale und vertikale Komponenten aufgelöst, und die Geometrie der Struktur wird angewendet, um den Winkel zwischen dem Bauteil ED und der horizontalen Kraftkomponente zu bestimmen.
Durch Anwenden der Kraftgleichgewichtsbedingung entlang der horizontalen Richtung wird sichergestellt, dass FED gleich FEC ist.
In ähnlicher Weise ergibt die vertikale Kraftgleichgewichtsbedingung die Kraft entlang des Elements ED.
Betrachten Sie nun ein Freikörperdiagramm für den Schnitt DAF. Die Momentengleichgewichtsbedingung kann auf das Gelenk F angewendet werden. 
Setzt man alle bekannten Werte in die Gleichung ein, erhält man die Kraft entlang des Elements AB.

<ol>
	<li>Hibbeler, R.C. (2016). Technische Mechanik \u2012 Statik und Dynamik. Hoboken, New Jersey: Pearson Prentice HallPppp 305.</li>
	<li>Bier, F.P.; Johnston, E.R.; Mazurek, D.F.; Cromwell, P.J. und Self, B.P. (2019). Vektormechanik für Ingenieure \u2012 Statik und Dynamik. New York: McGraw-Hill. Seite 348</li>
	<li>Meriam, J.L., Kraige, L.G. und Bolton, J.N. (2020). Technische Mechanik \u2012 Statik. Hoboken, New Jersey: John Wiley. Seite 200</li>
</ol>

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maschinen: problembehebung ii

Maschinen sind komplexe Strukturen bestehend aus beweglichen, mit Stiften verbundenen Mehrkraftgliedern, die zusammenarbeiten, um Kräfte zu übertragen. Betrachten Sie eine Hebzange, die eine Last von 100 kg trägt. Sie besteht aus den beweglichen Abschnitten DAF und CBG , die mit dem Glied AB verbunden sind.
<img alt="Figure 1" src="/files/ftp_upload/14295/14295_PT_Fig_1v2.svg" style="text-align: center; height: 350px;" />
Unter der Annahme, dass die Struktur am Punkt E symmetrisch ist, kann die auf das Glied AB wirkende Kraft berechnet werden.
Zunächst wird eine Freikörperdarstellung erstellt, die die Kräfte am Punkt E zeigt. Das Gewicht der Last, das der Masse mal der Erdbeschleunigung entspricht, wird auf 981 N berechnet. Die Zugkraft des Seils balanciert das Gewicht der Last und wirkt vertikal nach oben. ED und EC sind Zwei-Kraft-Glieder. Dadurch sind die Kräfte FED und FEC jeweils nach D und C gerichtet.
Anschließend werden die Kräfte FED und FEC in horizontale und vertikale Komponenten aufgelöst. Mit Hilfe der Geometrie der Struktur kann der Winkel zwischen dem Glied ED und der horizontalen Kraftkomponente als 30,96 Grad berechnet werden.
Die Gleichgewichtsbedingungen der Kräfte können auf den Knoten E angewendet werden.
<img alt="Equation 1" src="/files/ftp_upload/14295/14295_PT_Equation_1v2.svg" style="text-align: center; height: 13px;" />
<img alt="Equation 2" src="/files/ftp_upload/14295/14295_PT_Equation_2v2.svg" style="text-align: center; height: 13px;" />
Das Anwenden der Gleichgewichtsbedingung der Kräfte entlang der horizontalen Richtung stellt sicher, dass FED equals FEC gleich F_EC ist. Ebenso liefert die Gleichgewichtsbedingung der vertikalen Kraft den Wert von 953,46 N entlang des Glieds ED.
Nun wird eine Freikörperdarstellung für den Abschnitt DAF in Betracht gezogen. Die Momentengleichgewichtsbedingung kann auf den Knoten F angewendet werden.
<img alt="Equation 3" src="/files/ftp_upload/14295/14295_PT_Equation_3v2.svg" style="text-align: center; height: 13px;" />
Das Ergebnis ergibt die Kraft entlang des Glieds AB als 2423,76 N.
Das Verständnis der auf jedes Glied in diesem Hebzangensystem wirkenden Kräfte ist entscheidend für einen sicheren Betrieb und die Gestaltung effizienter Hebermechanismen. Indem die Kräfte analysiert und Gleichgewichtsbedingungen angewendet werden, können Ingenieure die Struktur optimieren und sicherstellen, dass sie Lasten unter verschiedenen Bedingungen sicher tragen kann.

Maschinen: Problembehebung II

Maschinen sind komplexe Strukturen, die aus beweglichen, mit Stiften verbundenen Multikraftelementen bestehen, die zusammenarbeiten, um Kräfte zu übertragen. Betrachten Sie eine Hebezange ...

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Machines: Problem Solving II

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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machines: problem solving ii

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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