Mechanism Lab
How Machines Move — Explained with Animations
Clear, original explanations of the mechanisms hidden inside everyday machines. Every article is illustrated with hand-built animated diagrams, so you can watch the mechanism work instead of guessing from a static picture.
Latest articles
CVTs: The Transmission With No Gears At All
Why hunt for the right gear when you can have every ratio at once? See how sliding cone pulleys and a steel belt sweep continuously from crawler to overdrive.
Power TransmissionDifferentials: The Gearbox That Lets Two Wheels Disagree
In a corner, the outer wheel travels farther than the inner one. The differential lets both wheels share one engine input while rotating at different speeds — a motion-cancelling miracle of bevel gears.
Power TransmissionBelt Drives: Quiet Power Across a Room
A rubber loop can carry serious power between shafts metres apart — quietly, cheaply, and with a built-in safety clutch. See how pulleys trade speed for torque on a moving belt.
Power TransmissionChain Drives: The Positive Link Between Belt and Gear
A chain is a belt you can trust: metal links that positively engage sprocket teeth, carrying high torque with zero slip over long distances. See why engines and bicycles depend on it.
Escapements & TimingThe Flyball Governor: The First Machine That Controlled Itself
Two spinning balls on a shaft gave the industrial revolution its nervous system. See how the flyball governor held steam engines steady — and founded the science of feedback control.
Escapements & TimingThe Anchor Escapement: The Sound of Time Being Counted
Every tick of a pendulum clock is an escapement releasing exactly one tooth. See how the anchor converts swing into counted, audible time — and why it changed history twice.
Escapements & TimingThe Lever Escapement: Why Mechanical Watches Survived the Quartz Age
A watch ticks 20,000 times an hour for years on one winding. The lever escapement makes that possible — a jewel-tipped dance between balance wheel, fork and escape wheel.
Locking & IndexingGeneva Drives: Turning Spinning into Perfect Stepping
The Geneva mechanism converts smooth rotation into exact, dwell-separated steps — the mechanical secret behind film projectors, indexing tables and counting machines.
Locking & IndexingIndexing Mechanisms: How Machines Move Exactly One Step at a Time
Turrets, carousels and counters all share one need: move precisely one station, then hold. See how pawls, star wheels and detents convert rotation into counted steps.
LinkagesThe Linkage That Walks: Chebyshev’s Lambda Machine
In the 1860s, mathematician Pafnuty Chebyshev designed a three-bar linkage whose foot traces a flattened path — and built walking machines decades before robots existed. Watch one walk.
Locking & IndexingOverrunning Clutches: The Bearing That Decides When to Grip
A one-way clutch locks instantly in one direction and freewheels in the other — with no switch, no sensor, nothing but wedge geometry. See how sprags, rollers and ramps do it.
LinkagesCrank and Slider: The Mechanism Inside Every Piston Engine
The crank-slider converts rotation to reciprocation and back — it is the beating heart of engines, compressors and pumps. Watch the linkage move and learn why the strokes are not symmetric.
LinkagesDrawing a Perfect Straight Line with No Slides: The Peaucellier Linkage
For 2,000 years nobody could make a machine trace a mathematically straight line — until 1864, when a French naval officer solved it with nothing but seven bars. See it move.
GearsHarmonic Drives: Zero Backlash from a Flexing Cup of Metal
The harmonic drive achieves enormous reduction with literally zero backlash by flexing a thin metal cup into a travelling wave. See how robot joints get their ghost-smooth precision.
GearsHelical vs Spur Gears: Why Angled Teeth Run Quiet
Angle the teeth of a spur gear and everything changes: the mesh becomes gradual, the noise becomes a hum, and a new force appears. See the comparison in motion.
GearsRack and Pinion: How Rotary Motion Becomes Perfectly Straight
The rack and pinion converts spinning shafts into dead-straight linear motion — and back again. See how steering wheels, 3D printers and CNC machines all rely on this simplest of gear pairs.
GearsWorm Drives: The Gear That Turns Rotation 90 Degrees and Holds Its Ground
A worm drive trades speed for brute reduction in one compact stage — and it can be made impossible to back-drive. See how a screw turns a wheel, and why elevators trust it.
LinkagesThe Four-Bar Linkage: The Simplest Machine That Draws Curves
Four bars, four joints, endless motion. See how the four-bar linkage turns steady rotation into rocking and tracing motion, why Grashof’s law predicts its behaviour, and where you meet it daily.
GearsPlanetary Gearsets: One Input, Many Personalities
A planetary gearset packs sun, planets, ring and carrier into one compact unit — and produces wildly different gear ratios depending on which part you hold still. Watch the carrier dance in the animation.
Locking & IndexingRatchet and Pawl: The Mechanism That Only Says Yes
A ratchet lets motion through in one direction and slams the door on the other. See how the pawl rides and catches the teeth, and why this humble pair of parts runs winches, sockets and seatbelts.
GearsHow Spur Gears Work: Teeth, Pitch Circles and the Grammar of Rotation
Spur gears are the simplest gears ever invented — and the foundation of every gear system. See how meshing teeth transfer rotation, why gear ratio matters, and what the pitch circle really means.