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Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force.
However, in some machines, if the frictional forces are high enough, no amount of load force can move it backwards, even if the input force is zero. This is called a self-locking, nonreversible, or non-overhauling machine. [29] These machines can only be set in motion by a force at the input, and when the input force is removed will remain ...
If the input force F A is applied to the edge of the wheel A and the force F B at the edge of the axle B is the output, then the ratio of the velocities of points A and B is given by a/b, so the ratio of the output force to the input force, or mechanical advantage, is given by = =.
The Peaucellier linkage generates a true straight-line output from a rotary input. The Sarrus linkage is a spatial linkage that generates straight-line movement from a rotary input. The Klann linkage and the Jansen linkage are recent inventions that provide interesting walking movements. They are respectively a six-bar and an eight-bar linkage.
If a is the distance from the pivot to the point where the input force is applied and b is the distance to the point where the output force is applied, then a/b is the mechanical advantage of the lever. The fulcrum of a lever is modeled as a hinged or revolute joint. Wheel: The wheel is an important early machine, such as the chariot.
On the other hand, if the distance a from the fulcrum to the input force is less than the distance b from the fulcrum to the output force, then the lever reduces the input force. The use of velocity in the static analysis of a lever is an application of the principle of virtual work.
where F A is a force acting on point A on the rigid lever beam, F B is a force acting on point B on the rigid lever beam and a and b are the respective distances from points A and B to the pivot point. If F B is the output force and F A is the input force, then mechanical advantage MA is given by the ratio of output force to input force.
Mechanical linkages are usually designed to transform a given input force and movement into a desired output force and movement. The ratio of the output force to the input force is known as the mechanical advantage of the linkage, while the ratio of the input speed to the output speed is known as the speed ratio. The speed ratio and mechanical ...