Recent Blogs
Watt Straight-Line Linkage: Animation and Path Calculator | FIRGELLI
Explore a Watt four-bar, vary link lengths and input sweep, and compare approximate straight-line travel with the actual sampled lateral deviation.
Barrel Cam: Rise–Dwell–Return Timing
Explore barrel-cam rise, dwell and return phases. Check that angles fit one revolution and calculate mean follower speeds and dwell time.
External Geneva Drive: Index and Dwell
Explore an external Geneva drive and calculate index, engagement and dwell angles from slot count, plus the driver period from rotation speed.
Bennett's Linkage Mechanism Explained: How It Works, Geometry, Formula, Uses & Animation
Explore Bennett’s spatial four-revolute linkage. Compare alternating lengths and twists, required-angle solutions and ideal closure, with mismatches shown as open chains.
Double Wishbone Suspension Mechanism: How It Works, Parts, Geometry & Camber Gain Explained
Explore front-view double-wishbone geometry. Adjust arm reaches, upright spacing and lower-joint bump to calculate camber rate and wheel-centre movement.
Two-shaft Slotted Crank: Ideal Offset and Speed Calculator
Explore a crank pin sliding in a radial follower slot. Calculate normalized shaft offset and ideal speed extrema from a selected fast-to-slow ratio and input...
Slotted Cross-head with Sliding Journal Box: How It Works, Diagram, Parts, Formula and Uses Explained
Explore a slotted cross-head and sliding journal box with an animated calculator for stroke, position, velocity and acceleration.
Slotted Connecting Rod with Rest at End: Mechanism, Diagram, Formula, and Uses Explained
Explore a crank pin moving through a slotted connecting rod. Compare selected slot travel, ideal slide stroke, rest share and rest time.
Drag-link Mechanism (d-class): How It Works, Parts, Formula & Quick-Return Uses Explained
Explore a D-class drag-link four-bar: adjust the four link lengths to compare output speed, Grashof classification and equal-angle half-turn times.
Double-rack Crank Substitute Mechanism: How It Works, Parts, Formula, and Industrial Uses Explained
See a double rack shift around a fixed pinion while its output slides straight. Calculate stroke, transverse travel, speed and full cycle time including reversals.
Crank to Oscillating Rod Reciprocating Mechanism: How It Works, Diagram, Formula & Uses
Explore a crank-driven oscillating rod. Calculate output angular range, one-way tip arc, minimum transmission angle and full-turn closure from four link lengths.
Crank Substitute Mechanism: How the Planetary Gear Slider-Crank Works, Parts & Uses
Explore an internal-gear crank substitute. Compare the straight-line 2:1 case with changed tooth counts or pin offset, and calculate first-turn spans and peak pin speed.
Worm-gear Jumping Motion with Tumbler Explained: How It Works, Parts, Uses, and Step-Rate Formula
Explore worm-and-tumbler indexing. Compare step angle, steps per minute and ideal engagement time from your entered tooth count and cycle settings.
Rack-Rod from a Mutilated Spur Gear: Ideal Advance/Dwell Ledger
How a mutilated spur-gear drives a rack-rod for intermittent linear motion — geometry, formulas, worked example, and packaging-line applications.
Slotted Lever Motion Mechanism Explained: How It Works, Quick Return Geometry, Parts and Uses
Explore a crank and slotted lever, its tangent reversal positions, and the ideal work-to-return time ratio.
Irregular Rocking Motion: Work and Return Allocation Calculator | FIRGELLI
Watch a crank pin drive a grooved rocking arm. Separately compare two entered angular allocations, their ratio and normalized shares.
Continuous to Alternating Crank Gears: How the Mutilated Sector Gear Mechanism Works
Explore a partial bevel gear alternately driving opposed gears on a common shaft. Compare angular stroke, tooth-free gaps and reversal rate.
Combination Crank-motion Curves: Crank-Rocker Linkage and Interactive Pen Trace
Explore the curve drawn by a pen on a crank-rocker’s rigid connecting arm. Change link lengths, pen offset, starting angle and cycle time.
Wittgenstein's Rod: Clearance and RSS Error-budget Calculator
Compare entered rod clearance, pin play and straightness with an assumed root-sum-square budget. The tool does not solve linkage motion or production tolerances.
Tusi Couple: Two-to-one Geometry and Straight-line Stroke
Explore the ideal straight-line trace of a circle rolling inside a circle twice its diameter. Calculate stroke and amplitude for the exact two-to-one case.
Scott Russell Linkage Mechanism Explained: Diagram, Formula, Stroke and Uses
Scott Russell linkage explained — how this straight-line mechanism converts rotary motion into perfectly linear travel for test rigs, lifts, and lab equipment.
Roberts Linkage Mechanism: How It Works, Diagram, Formula, and Uses in Straight-Line Motion
Roberts Linkage explained — a four-bar straight-line mechanism used in robotics, prosthetics, and instrument design. Geometry, formulas, and a worked example.
Hoecken Linkage: Link-Length Scaling and Model Limits | FIRGELLI
Explore approximate straight-line linkage geometry and calculate scaled link lengths. Velocity variation, usable stroke, full-cycle closure and payload are not verified by this tool.
Grashof Linkage: Four-Bar Assembly and Rotation Calculator | FIRGELLI
Check four link lengths for assembly and Grashof rotation. Compare sorted sums and margin, with a longest-ground four-bar animation and worked example.
Origami Vertex Angle Calculator: Kawasaki Condition | FIRGELLI
Check four sector angles at one origami vertex. See alternating angle sums, total angle and deviation from Kawasaki’s local flat-foldability condition.