LINKAGES

A series of rigid links connected by joints. Usually forms a closed chain.Simple, right?

Uses of Linkages

A LINKAGE IS A MECHANISM IF TWO OR MORE LINKS MOVE WITH RESPECT TO A FIXED LINK.

LINKAGES CAN:

>Take an Input and produce a different Output>Alter the shape of motion (curves)>Change velocity, acceleration of motion>Apply Mechanical Advantage

Expect a lot of ROTATING, OSCILLATING and RECIPROCATING

4-BAR LINKAGESSimplest closed-loop kinematic links.

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4-BAR LINKAGESThink about: Your windshield wipers.

OTHERPantographs

Transfer, ScaleDrawing and Writing!

Make one quickly out of cardboard andimpresses people at parties.

Link: Nova Jiang

OTHERPolygraph

Thomas Jefferson’s Polygraph (1804)

WALKINGKlann Linkage

For creepy, spider walking...Remember: Theo Jansen’s mechanism

STRAIGHT-LINE LINKAGESPaucellier-Lipkin

Oscillation into Straight Line

STRAIGHT-LINE LINKAGESWatts

OTHERThe Bell-Crank

OTHERHoekens Linkage

More approximate “Straight-Line Motion” but also makes a nice mushroom shaped curve.

OTHERAccordion Motion

Link

LinkageLab!

TRY IT OUT:

> Play around with linkage configurations.> Use a pencil to trace curves.

> Design a PANTOGRAPH to copy or scale motion >Can you figure out Mirror Writing?

> Combine linkages with gears and circles to make cranks, pistons, etc.

Web Resources for Linkage Analysis:

“Web Based Mechanism Design and Analysis”

“Mechanisms 101” Flash Applets

Cornell KMODDL Library. Linkage Tutorial/History

Fin.