Name: wedges and self-locking stability
Uploaded: 2025-05-22T09:06:04.000Z
Duration: 1 min 24 s
Channel: JoVE

Una cuña es una máquina que es útil para ajustar la elevación de piezas estructurales o mecánicas, proporcionar estabilidad para objetos pesados y dividir un cuerpo en dos partes.
Considere usar una cuña para levantar una losa pesada.
La cuña amplifica la fuerza aplicada en una fuerza mucho mayor dirigida casi perpendicularmente a la fuerza aplicada.
Hay siete incógnitas, incluida la fuerza aplicada para el movimiento de la cuña y seis fuerzas normales y de fricción.
Se pueden determinar utilizando cuatro ecuaciones de equilibrio de fuerzas aplicadas a la cuña y la losa y tres ecuaciones de fricción aplicadas a cada superficie de contacto.
Para bajar la losa, las fuerzas de fricción actúan en sentido contrario.
Siempre que el coeficiente de fricción sea muy pequeño o el ángulo de la cuña sea grande, la fuerza aplicada debe actuar hacia la derecha para sujetar la losa.
Si se elimina la fuerza aplicada y las fuerzas de fricción sostienen el bloque, la cuña se considera autoblocante. Esta condición es válida solo cuando el ángulo de cuña es menor que el doble del ángulo formado por las fuerzas de reacción.

<ol>
	<li>Hibbeler, R.C. (2016). Ingeniería Mecánica: Estática. Decimocuarta edición, Nueva Jersey: Pearson. Págs. 430-431.</li>
	<li>Meriam, J.L., Kraige, L.G. y Bolten, J.N. (2016). Ingeniería Mecánica: Estática y Dinámica. Octava edición, Singapur: John Wiley & Sons. Págs. 353-354.</li>
	<li>Beer, F.P., Johnston, E.R., Mazurek, D.F., Cornwell, P.J. y Self, B.P. (2016). Mecánica vectorial para ingenieros. Undécima Edición, Nueva York: McGraw-Hill Education. Págs. 450.</li>
</ol>

cuñas

Una cuña es una máquina simple que cumple varios propósitos, como ajustar la elevación de partes estructurales o mecánicas, proporcionar estabilidad para objetos pesados y dividir un cuerpo en dos partes. Esta herramienta versátil puede amplificar una fuerza aplicada, haciendo más fácil manipular objetos grandes o pesados. Considera usar una cuña para levantar una losa pesada. Aquí, la cuña funciona convirtiendo la fuerza aplicada en una fuerza mucho mayor, dirigida casi perpendicular a la fuerza inicial. Esta amplificación permite levantar objetos pesados con un esfuerzo mínimo. Hay siete factores desconocidos involucrados en el movimiento de la cuña: la fuerza aplicada y seis fuerzas normales y de fricción. En los diagramas de cuerpo libre, el peso de la cuña se suele omitir, ya que es pequeño en comparación con la carga. <img alt="Figure 1" src="/files/ftp_upload/14317/14317_PT_Figure_1v2.svg" style="text-align: center; height: 300px;"> Estos desconocidos se pueden determinar mediante cuatro ecuaciones de equilibrio de fuerzas aplicadas a la cuña y la losa, <img alt="Equation 1" src="/files/ftp_upload/14317/14317_PT_Equation_1v2.svg" style="text-align: center; height: 13px;"> <img alt="Equation 2" src="/files/ftp_upload/14317/14317_PT_Equation_2v2.svg" style="text-align: center; height: 13px;"> <img alt="Equation 3" src="/files/ftp_upload/14317/14317_PT_Equation_3v2.svg" style="text-align: center; height: 13px;"> <img alt="Equation 4" src="/files/ftp_upload/14317/14317_PT_Equation_4v2.svg" style="text-align: center; height: 13px;"> y las tres ecuaciones de fricción restantes (F1, F2, F3) aplicadas en cada superficie de contacto se dan por el coeficiente de fricción del producto y sus respectivas fuerzas normales. Al resolver estas ecuaciones, se puede obtener una visión de la relación entre la fuerza aplicada y el movimiento resultante de la cuña. Al bajar la losa, las fuerzas de fricción actúan en sentido contrario. Siempre que el coeficiente de fricción sea muy pequeño o el ángulo de la cuña sea grande, la fuerza aplicada debe actuar hacia la derecha para mantener la losa en su lugar. Este equilibrio de fuerzas garantiza que la cuña se mantenga estable y mantenga su posición mientras soporta el peso de la losa. Bajo ciertas condiciones, la cuña se considera autotrabante. Esto ocurre cuando se retira la fuerza aplicada y las fuerzas de fricción solas pueden mantener el bloque en su lugar. La condición de autotrabado es válida solo cuando el ángulo de la cuña es menor que el doble del ángulo formado por las fuerzas de reacción. En este caso, la geometría de la cuña y la fricción entre las superficies de contacto trabajan juntas para evitar movimientos o deslizamientos no deseados. La propiedad de autotrabado de una cuña puede ser ventajosa en varias aplicaciones, ya que proporciona estabilidad y seguridad adicional al manipular objetos pesados. Por ejemplo, en proyectos de construcción o ingeniería, una cuña autotrabante puede ayudar a garantizar que los componentes estructurales permanezcan firmemente en su lugar durante el montaje o los ajustes.

Cuñas

Una cuña es una máquina simple que sirve para varios propósitos, como ajustar la elevación de las piezas estructurales o mecánicas, proporcionar estabilidad ...

Education

Educación

JoVE Core

Mechanical Engineering

Ingeniería Mecánica

Unit 1

Unidad 1

Friction

Fricción

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

Wedges

wedges and self-locking stability

A wedge is a simple machine that can lift, support, and split heavy objects. It can also change the height of structural or mechanical parts. Because it amplifies force, a wedge makes it easier to move or hold large loads with less effort.

One example is lifting a heavy slab. In that case, the wedge turns the applied force into a much larger force that acts almost perpendicular to the original push. That force change helps raise the load without requiring a large input force.

To analyze wedge motion, there are seven unknowns. These include the applied force, six normal forces, and frictional forces at the contact surfaces. The wedge weight is often ignored in the free-body diagrams because it is small compared with the load.

The unknowns can be found with four force equilibrium equations for the wedge and the slab. Three friction equations, F1, F2, and F3, are then applied at each contact surface. Each friction force equals the coefficient of friction times the normal force at that surface.

The same force balance also explains what happens when the slab is lowered. In that case, the friction forces act in the opposite direction. If the coefficient of friction is very small or the wedge angle is large, the applied force must act to the right to keep the slab in place.

A wedge can also be self-locking. This means that when the applied force is removed, friction alone can hold the block in place. The self-locking condition works only when the wedge angle is less than twice the angle made by the reaction forces.

This stability is useful in many settings. In construction or engineering work, a self-locking wedge can help keep parts firmly in place during assembly or adjustment. The geometry of the wedge and the friction between surfaces work together to reduce slipping and unwanted motion.

Wedges and Self-Locking Stability

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wedges

A wedge is a simple machine that can lift, support, and split heavy objects. It can also change the height of structural or mechanical parts. Because it amplifies force, a wedge makes it easier to move or hold large loads with less effort. One example is lifting a heavy slab. In that case, the wedge turns the applied force into a much larger force that acts almost perpendicular to the original push. That force change helps raise the load without requiring a large input force. To analyze wedge...

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key terms and concepts

Learn how wedges amplify force, lift heavy slabs, and stay in place through friction. Explore equilibrium, contact forces, and self-locking stability.

Wedges and Self-Locking Stability | 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.

mechanical engineering

Wedges and Self-Locking Stability

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