Category:Linkages

A linkage is a mechanism made by connecting together rigid links or levers.

Levers or links may be connected together using a wide range of fastenings which allow free movement - e.g. screws, split pins, paper fasteners, pop rivets, clevis pins, nuts and bolts, etc. The linkage can be made to change the magnitude or direction of a force or make two or more things move at the same time - or, as in the example of Pantograph shown, they can be used to amplify movement.

Linkages which makes things move in opposite directions may be called Reverse Motion Linkages and linkages which makes the output move in the same direction as the input may be called Push-Pull Linkages.

As with other mechanisms, the Mechanical Advantage of a linkage is calculated by dividing the force generated at the output (load) by the input force (effort). The Velocity Ratio is given by dividing the distance moved at the input by the distance moved at the output of the linkage. In an ideal friction free world, these two values would be equal but this is most unlikely to be so in the case of complex linkages with their many opportunities for loss of energy, if the joints are too tight, or of movement if they are too loose.