Recent Blogs
Hinge Loads: Ideal Two-Hinge Door Moment Calculator | FIRGELLI
Calculate the ideal horizontal hinge-force couple for a uniform door from mass, width and hinge spacing. Fastener forces, hardware capacity and impact loads are not...
Hart's Inversors: Crossed-Link Motion and Geometry Calculator
Explore a Hart inversor with a crossed four-link cell, circular input and straight tracing point. Calculate the midpoint inversion constant from full bar lengths.
Hart's Exact Straight-Line Inversor: Stroke and Animation
Size an ideal Hart inversor stroke from full bar lengths. See the crank angle, available travel and connected crossed-link motion without a sliding guide.
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.
Closed Four-Link Chain: Planar Mobility Calculator | FIRGELLI
Explore planar link and joint counts, the Gruebler–Kutzbach equation and a four-bar illustration. Understand connectivity and constraint assumptions.
Four-Bar Linkage: Grashof Margin and Geometry Explorer | FIRGELLI
Explore four-bar lengths, Grashof margin and sampled angles. Learn the limits of branch selection, angle spans and the illustrative index.
Evans Grasshopper Linkage: Coupler-Path Calculator | FIRGELLI
Explore an Evans four-bar linkage with an approximately straight coupler path. Compare link scale, crank sweep, traced stroke and lateral wander.
Eight-bar Linkage Mechanism Explained: How It Works, Parts, Diagram and Grübler DOF Formula
Explore a Jansen-type eight-bar walking leg with a calculated foot path. Adjust scale, crank radius and speed; see rigid links, joint count, travel and gait...
Drum and Rope Conversion Mechanism Explained: How Winch Drums Convert Rotation to Linear Pull
Explore winding-drum rotation and tangential rope travel. Calculate line speed, travel per turn and ideal pull from effective diameter, rpm and shaft torque.
Drag-link Mechanism Explained: How It Works, Parts, Diagram, Quick-Return Uses & Formula
Explore a drag-link four-bar with adjustable link lengths and input speed. Calculate Grashof margin, variable output rpm and two output half-turn times.
Double-rocker Mechanism: How It Works, Parts, Formula, Diagram and Uses in Four-Bar Linkages
Explore a double-rocker four-bar linkage. Set four link lengths to calculate assembly class, feasible input limits and sampled output swing.
Double-crank Mechanism Explained: How It Works, Diagram, Parts, Grashof Condition and Uses
Explore a double-crank four-bar linkage. Adjust link lengths, check the Grashof condition, and calculate instantaneous output speed through the cycle.
Diagonal Catch Hand-gear (top of Cylinder): Mechanism, Parts & Calculator Explained
Explore Brown 182 diagonal catch valve gear for pumping engines. See the four-valve sequence and calculate ideal cylinder force, volume and piston speed.
Diagonal Catch Hand-gear (raising Piston): Mechanism, Parts, Diagram and Formula Explained
Explore Brown 181 diagonal catch valve gear for pumping engines. See the four-valve sequence and calculate ideal cylinder force, volume and piston speed.
Crossed-slider Chain Mechanism Explained: How It Works, Parts, Formula, and Uses
Explore an elliptic trammel with a tracing point between two slider pins. Calculate ellipse width, height, area and pin spacing, and compare slider travel.
Crank-rocker Mechanism: How It Works, Diagram, Parts, Formula, and Industrial Uses Explained
Explore four-bar linkage geometry. Check full input rotation, output angular range, Grashof margin and minimum transmission angle from four entered link lengths.
Compliant Mechanism: Flexure Motion, Pin-Joint Clearance and Uses Explained
See how flexible leaves guide a moving stage. Compare new and worn pin-joint clearance, and understand why zero joint clearance does not mean perfect positioning.
Cognate Linkage Mechanism: How It Works, Roberts-Chebyshev Theorem, Diagram and Uses Explained
Compare three Roberts–Chebyshev four-bar cognates tracing one point path. Scale the coupler triangle and inspect matching configurations and different fixed pivots.
Chebyshev Linkage: Double-Rocker Motion and Coupler-Midpoint Path
Explore a Chebyshev double-rocker linkage. Adjust four link lengths and compare sampled horizontal span and vertical variation of the coupler midpoint.
Carpenter's Bench-clamp Mechanism Explained: How It Works, Parts, Formula, Diagram
See how a curved-arm holdfast contacts a workpiece and bench hole. Compare shank clearance and geometric contact tilt from hole diameter, shank diameter and bore...
Cardan Straight-line Mechanism: How It Works, Diagram, Formula, and Uses Explained
Explore the Cardan straight-line mechanism: a half-size pinion inside a fixed ring. Compare pitch diameters, stroke and tooth counts in the ideal 2:1 geometry.
Bricard Exact Straight-Line Mechanism: Linkage Animation and Travel Calculator
Explore Bricard’s planar straight-line linkage. Adjust pivot spacing and crank sweep to calculate link lengths and the perpendicular travels of Q and D.
Bell-crank with Weighted Cord and Pulley Mechanism: How It Works, Parts, Formula, and Uses
Bell-crank with weighted cord and pulley explained — how the linkage converts gravity into linear pull for gates, signals, and theatre rigging. Formula and worked...
Bell-crank Lever (changing Direction of Force): Mechanism, Diagram, Animation & Calculator Explained
Bell-crank lever explained: how this 90° force-redirecting linkage works, with formulas, worked examples, and real uses in aircraft controls and machinery.