Recent Blogs
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.
Rack and Pawl: Declared Index-Pitch Ledger
How a Rack and Pawl mechanism converts reciprocating motion into one-way linear indexing — design rules, formulas, and real applications in lift jacks and presses.
Otis 1861 Hoisting Safety Catch: Hooked Rack-and-Pawl Principle
Explore Otis’s 1861 rope-triggered rack-and-pawl hoisting catch. Count equally spaced positions on two racks from a chosen span and pitch.
Mutilated Gear Intermittent Drive: Tooth Sector and Holding Pair
Explore a mutilated gear with a holding ring and cam. Calculate ideal output step, sector arc, dwell fraction and dwell time from tooth counts and...
Mutilated Bevel Gear: Opposed Intermittent Outputs A and B
Explore Brown movement 74: one toothed sector alternately drives two opposed bevel gears. Calculate ideal output steps, engagement sectors and dwell angles.
Modified Two-Pawl Lever: Ideal Indexing
Explore a modified two-pawl lever that advances a ratchet one tooth on each half-stroke. Calculate ideal indexing rate and wheel speed from lever cycles and...
Lever to Slotted Rack via Two Hooked Pawls: How This Indexing Mechanism Works, Parts & Uses
See a driving pawl advance a slotted rack while a holding pawl retains each step. Calculate ideal cumulative travel from slot pitch and successful index...
Drop-and-Pawl Intermittent Rotation: Indexing Calculator | FIRGELLI
Compare star-wheel step angle, events per revolution and average event frequency. Brown movement 63 supplies the historical sequence; the current illustration does not solve contact...
Spherical Geneva Drive: Right-Angle Indexing Animation and Calculator
Explore a spherical Geneva with intersecting right-angle shafts. Calculate index angle, pin-cone angle and equal indexing and dwell times.
Internal Geneva Drive: Index Angle and Dwell Calculator | FIRGELLI
Calculate index angle, accumulated output travel and motion/dwell intervals for an ideal internal Geneva. Explore the radial-slot and drive-pin motion.
Geneva Drive (external) Mechanism Explained: How It Works, Diagram, Parts, Formula & Uses
Geneva Drive explained — how the external Geneva mechanism converts continuous rotation into precise indexed motion for film projectors, turrets, and packaging lines.
Maltese Cross Mechanism: Exact External-Geneva Timing
Explore an external Geneva mechanism. Calculate output step, driver indexing angle and dwell time from slot count and constant driver speed.
Driving Wheel with Internal Rim Guard: How It Works, Parts, Formula & Diagram Explained
Explore a tappet and studded disk with an inner retaining rim. Adjust spacing, stud count and speed to calculate contact timing and output steps.
Driving Disk with Rim and Stops Mechanism Explained: How It Works, Parts, Formula & Uses
Explore a tappet and studded disk with an outer retaining rim. Adjust spacing, stud count and speed to calculate contact timing and output steps.
Crown-ratchet (rag-wheel) Mechanism Explained: How It Works, Parts, Diagram and Uses
Explore an axial crown ratchet and sliding pawl. Calculate nominal angle per click, total index, ramp slope and stop-face deviation, with a developed tooth profile.
Continuous Rotary to Intermittent via Cam and Disk: How It Works, Parts, Formula and Uses
Explore a stepped cam and two-stop disk. Adjust shaft offset, scale and input speed to calculate half-turn indexing and stationary intervals.
Cam to Double-rack Frame with Governor: Mechanism, How It Works, Parts, Uses & Formula
Explore a governor-selected double-ratchet frame driven by a rotating pin. Compare feed direction, advance per revolution and mean selected feed rate.
Bent-spring Driver with Strong-spring Catch: How the Mechanism Works, Parts, Formula, and Uses
Explore a bent spring on a rotating carrier engaging an intermittent ratchet through a fixed catch. Compare spring rates, preload and catch seating force.
Spur-gear Stops Mechanism: How It Works, Diagram, Formula, and Uses Explained
Spur-gear Stops limit rotation to a fixed number of turns in safes, winches, and counters. See how they work, the math, and real industrial examples.
Lantern-wheel Stops: Roller Clearance and Motion Calculator
See a roller arm release and arrest a lantern wheel. Compare arc pitch, straight trundle clearance and a circular stop’s geometric fit.
Intermittent Motion: Geneva Index and Dwell Calculator | FIRGELLI
Compare ideal Geneva step and index/dwell fractions, including an overlap warning for equally spaced pins. Physical multi-pin compatibility is not established.
Silent Ratchet (friction) Mechanism Explained: How It Works, Diagram, Parts, Formula and Uses
Silent Ratchet (friction) explained — how friction-grip pawls index loads without clicking, with worked examples from elevator hoists and rod-feed lathes.
Wharf Crane: Load-radius and Counterweight Comparison
Explore a wharf-crane load and counterweight comparison. Adjust masses, radii and assumed factors; the results do not establish crane stability or capacity.
Truss Roof: Three-member Ideal Force Calculator
Explore an ideal three-member roof truss under a centered apex load. Calculate support reactions, rafter compression, tie tension and member length.
Toggle Stump Puller: Historical Arrangement and Ideal Toggle Ratios
Explore a historical stump-puller subject with an abstract two-link toggle model. Calculate ideal force and travel ratios, without predicting chain load or capacity.