Recent Blogs
Straight-line Linkage
Straight-line linkages convert rotary motion into pure linear travel without slides. Learn the geometry, tolerances, and real applications in precision machining.
Chebyshev Plantigrade Machine
Chebyshev Plantigrade Machine explained — how the linkage produces straight-line walking, real applications in robotics and museum exhibits, plus a worked build example.
Krueger Flap Mechanism
Krueger flap mechanism explained — how leading-edge flaps deploy from the wing underside on Boeing 747 and 777 to boost lift coefficient at takeoff and...
Inverted Slider-crank
Inverted slider-crank explained — how the mechanism works, where it's used in steam engines, hand pumps and quick-return shapers, with formulas and worked example.
Drag-link Mechanism (d-class)
Drag-link Mechanism explained: how the d-class four-bar produces continuous unequal rotation, sizing rules, and real applications in printing, packaging and shapers.
Continuous Rotary via Two Paired Link Cranks
Two paired link cranks convert reciprocating drive into smooth continuous rotary motion — used in steam locomotives, pump drives, and industrial machinery.
Slider-crank Linkage
Slider-crank Linkage explained: how it converts rotation to linear motion, real engine and pump examples, sizing math, and tolerance rules from FIRGELLI engineers.
Adjustable Link
Adjustable Link explained — how the variable-length connecting rod tunes valve timing, ignition advance, and stroke in gas engines, with formulas and a worked example.
Burmester Theory Linkage
Burmester theory linkage explained — how engineers use four-position synthesis to design four-bar linkages that hit precise poses in robotics and aerospace.
Oscillating Column (form 2)
Oscillating Column form 2 explained — how the sliding-block linkage drives reciprocating motion in shapers, looms, and pump mechanisms. Engineering guide.
Irregular Rocking Motion
Irregular rocking motion converts steady rotation into uneven oscillation. See how the linkage works, design formulas, and real machinery uses in textiles and packaging.
Combination Crank-motion Curves
Combination crank-motion curves explained — how stacked four-bar linkages generate complex output paths for packaging, textile, and assembly machines.
Parallel Plyers
Parallel pliers keep jaws flat and parallel through their full travel — used in jewellery, watchmaking and electronics for crush-free gripping on flats and tubes.
Link Transmission
Link Transmission explained: how rigid-link mechanisms transfer power in presses, locomotives and packaging machines, with formulas, ratios and a worked example.
Watt's Linkage
Watt's Linkage explained — how the four-bar generates near-straight motion, design rules, worked example, and real uses in vehicle suspensions and engines.
Steering Linkage
How a Steering Linkage works, with Ackermann geometry, tie rod sizing, bump steer math, and a worked example for an off-road truck build. Engineer's guide.
Slider Crank Chain Inversion
Slider crank chain inversions explained — how fixing different links creates oscillating engines, Whitworth quick-return, and rotary pumps used in machine tools.
Roberts Linkage
Roberts Linkage explained — a four-bar straight-line mechanism used in robotics, prosthetics, and instrument design. Geometry, formulas, and a worked example.
Parallel Ruler (form 6)
Form 6 Parallel Ruler explained — how the four-bar linkage keeps the straightedge parallel during translation, with worked numbers for drafting and marine chart work.
Parallel Ruler (form 5)
Parallel Ruler form 5 explained — the four-bar lazy-tongs linkage that lets draftsmen, navigators and CNC operators transfer parallel lines across a chart or drawing.
Parallel Ruler (form 4)
Parallel Ruler form 4 explained — the four-bar linkage drafting tool used by navigators and architects to transfer parallel lines across charts and drawings.
Parallel Ruler (form 2)
Parallel Ruler form 2 explained — how the four-bar linkage holds true parallel motion across a drafting board, with formulas, tolerances, and worked examples.
Parallel Ruler (form 1)
Parallel ruler linkage explained — how the four-bar parallelogram keeps a straight edge parallel during translation, with worked drafting and CNC examples.
Pantograph
How a Pantograph linkage scales drawings, engraves nameplates, and copies CNC paths. Geometry, formulas, tolerances, and a worked example for makers and engineers.
Inverted Slider-crank Chain
Inverted slider-crank chain explained — kinematics, formulas, and real machine examples from hand pumps to Whitworth quick-return shapers and steam reverse gear.