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.
Chebyshev Plantigrade Machine: How This Walking Linkage Works, Parts, Formula, and Uses Explained
Explore four Chebyshev linkages driving two alternating foot frames. Calculate foot sweep, lift and the small height variation along the approximately level stance path.
Knee-action Toggle Clamp: Over-centre Motion and Force Calculator
See a hold-down toggle pass through dead centre and meet its stop. Explore a defined four-bar force calculation while keeping clamping force separate from holding...
Inverted Slider-Crank: Oscillating-Axis Swing Calculator | FIRGELLI
Calculate the angular envelope of an oscillating axis from crank radius and trunnion spacing, with an explicit C greater than r condition. Piston travel and...
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.
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.
Continuous Rotary via Two Paired Link Cranks: How the Mechanism Works, Parts & Uses Explained
Explore two crank pairs connecting parallel shafts. Compare phase offsets and normalized torque contributions from two ideal equal-force coupling rods.
Slider-crank Linkage Mechanism: How It Works, Diagram, Formula, Parts, and Real-World Uses
Slider-crank Linkage explained: how it converts rotation to linear motion, real engine and pump examples, sizing math, and tolerance rules from FIRGELLI engineers.
Burmester Theory: Four-bar Body Guidance and Pivot-Offset Calculator
Explore Burmester body-guidance principles and a four-bar example. Compare coupler-point displacement at four input angles after a fixed-pivot offset.
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.
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.
Ornithopter Crank–Rocker Drive Geometry
Explore an ornithopter crank-rocker drive. Change four link lengths to compare the rocker-angle range and endpoint chord of an ideal planar linkage.
Bisecting Gauge Mechanism: How It Works, Parts, Formula and Uses Explained with Diagram
Explore a four-link angle-bisecting gauge. Set two arm directions to calculate the bisector, included angle and equal half-angles.
Parallel Plyers: Exact Parallelogram Jaw Geometry
Explore ideal parallel-jaw geometry using an equal-link parallelogram. Calculate horizontal offset, jaw separation, parallelism and the long diagonal.
Link Transmission Mechanism: How Four-Bar Linkages Work, Parts, Transmission Angle and Uses
Explore transmission angle at a coupler-to-rocker joint. Calculate normalized tangential and radial force components and compare the angle with a chosen band.
Alternating Circular Motion Mechanism: How It Works, Crank-Rocker Diagram, Parts and Uses
Explore a crank-rocker converting full rotation into angular oscillation. Compare crank-length error using an explicit assumed sensitivity separate from the animated geometry.
Watt's Linkage: Illustrated Path and Cubic Comparison
View the midpoint path of a fixed illustrative Watt four-bar. Compare an assumed cubic expression with an entered allowance; it is separate from the drawn...
Steering Linkage Mechanism Explained: Ackermann Geometry, Parts, Diagram and Calculator
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 Mechanism: How It Works, Diagram, Parts and Uses Explained
Explore a crank-driven slotted lever and connected ram, and compare ideal long and short stroke times from crank radius, pivot spacing and speed.
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.
Parallel Ruler (Form 6): Ideal Alternating Walk Sequence
Explore parallel-ruler motion. Calculate the components of one equal-link transfer and the total perpendicular advance for repeated transfers at a fixed angle.
Parallel Ruler (Form 4): Ideal Repeated-Line Transfer
Explore repeated transfers with an equal-link parallel ruler. Calculate perpendicular step size, full placement count, covered distance and final excess.
Parallel Ruler (Form 2): Hiscox Equal-Link Pivot Path
Explore Hiscox’s equal-link parallel ruler. Calculate longitudinal shift, perpendicular separation and circular pivot travel from link length and opening angle.
Parallel Ruler (Form 1): Exact Equal-Arm Translation
Explore an equal-arm parallel ruler. Calculate longitudinal shift, line separation, enclosed area and ideal parallelism from pivot spacing, arm length and angle.
Drawing Pantograph: Exact Homothetic Scale
Explore a rigid-link drawing pantograph. Calculate pencil-to-tracer scale, pencil-path length and ideal area scale from a reduction ratio.