Linkages
A linkage is a system of connected rods and levers that are used to transmit motion and force. Linkages may be used to:
- change the direction of motion and force
- change the size of the output motion compared to the size of the input motion
- create parallel motion
- change one type of motion into another type of motion.
![Linkage](images/Linkages_1.jpg)
The linkage above illustrates how the direction of motion and force may be changed.
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![Linkage transmitting motion and force](images/Linkages_2.jpg)
The diagram above illustrates how a linkage may be used to:
- change the direction of motion and force
- change the size of the output motion compared to the size of the input motion
- change the size of the output force compared to the size of the input force
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![Parallel motion linkage](images/Linkages_Parallel.jpg)
The diagram above illustrates how a linkage may be used to create a parallel motion.
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![Pantograph linkage](images/Linkages_Pantograph.jpg)
The diagram above illustrates a pantograph linkage. A pantograph is used to copy and rescale shapes and drawings.
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![crank and slider linkage](images/Linkages_power_hacksaw.jpg)
The diagram above illustrates how a linkage is used in a crank and slider mechanism
and how rotary motion is converted into reciprocating motion.
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![Fret saw parallel arm linkage](images/Linkages_fret_saw_2.jpg)
Parallel motion linkage used in a parallel arm fret saw.
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![Fret saw parallel link arm linkage](images/Linkages_fret_saw_1.jpg)
Linkages connected to two bell crank levers create a near vertical reciprocating sawing action.
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Linkages found in a sewing machine.
![Sewing machine linkages](images/Sewing_machine_linkages.jpg)
The photograph above shows various linkages and levers in a typical sewing machine. Also visible in the photograph is a belt and pulley drive, nylon bevel gears, retaining springs and lubricating grease. |