8.2 Mechanical Advantage

 

• As a mechanism moves over a range of motion its geometry changes. If we are using a mechanisms to transmit torque, or force then we must consider the ratio between the input and output force in various positions.

 

• Transmission angle is the angle between the coupling member and the output member in a mechanism. As this angle approaches ±90°, the mechanical advantage of the mechanism typically increases.

 

• Toggle positions occur when the input crank has near infinite mechanical advantage. Note: this also applies that the follower has no mechanical advantage on the crank.

 

• Consider the example below, [prob. 1-3 from Shigley & Uicker],

 

 

 

 

 

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