Recent Blogs
Four-pulley Two-speed Drive: Ideal Ratio Comparison
Compare two ideal no-slip speed ratios and their paired pitch-diameter sums. Equal diameter sums alone do not establish that the same belt fits both positions.
White's Pulleys Mechanism Explained: How a Single-Rope Stepped-Sheave Tackle Works
Explore pulley effort and rope travel using an entered mechanical advantage and efficiency. The simplified support-force sum is not an anchorage rating.
Vibratory Belt Motion: Segment-Lever Illustration and Harmonic Calculator
Compare two strokes and calculate ideal sinusoidal peak belt speed and acceleration under an explicit one-cycle-per-revolution assumption.
Three-pulley Two-speed Drive: Ideal Speed and Torque Ratios
Compare two stepped-pulley speed ratios and reciprocal lossless torque ratios. The schematic idler redirects the belt; belt fit, tension and shifting are not calculated.
Two Fixed and One Movable Pulley: Three-part Tackle Calculator
Explore the shown 3:1 tackle and compare haul force using an assumed per-sheave tension ratio. Results do not rate a lifting system.
Sprocket and Chain Drive Mechanism Explained: How It Works, Parts, Diagram, Formula and Uses
How a Sprocket and Chain Drive transmits torque without slip — pitch, ratio, and chain tension explained for conveyor, motorcycle, and robotics builds.
Spanish Barton (form 2) Mechanism Explained: 5:1 Compound Pulley Parts, Formula & Rigging Uses
Spanish Barton form 2 rigging explained — how stagehands and riggers achieve 5:1 mechanical advantage with two single blocks to lift heavy loads safely.
Spanish Barton (form 1) Mechanism Explained: 5:1 Compound Pulley Diagram, Parts and Uses
How the Spanish Barton form 1 tackle works, its 5:1 mechanical advantage, rigging formula, and worked example for lifting heavy loads in arborist and rescue...
Simple Lifting Pulley Mechanism: How It Works, Diagram, Parts, Formula and Uses Explained
Explore a fixed pulley with a continuous rope animation. Calculate effort from load and selected efficiency, plus the sheave-to-rope diameter ratio.
Movable-Pulley Cord System (d): Fixed-Redirect 2:1 Ledger
How a cord-and-movable-pulley system halves lifting force. Real worked example, mechanical advantage formula, and rigging examples for shop and field use.
Movable-Pulley Cord System (c): Standing-End and Haul-Line Ledger
How a cord-and-movable-pulley system halves lifting force in rigging, theatre, and workshop hoists. Mechanical advantage formulas, worked example, and diagrams.
Movable-Pulley Cord System (b): 2:1 Lift with Right-Angle Haul
Movable pulley systems with cord cut lifting force in half or better. See how riggers, theatres, and shipyards use them to hoist heavy loads with...
Movable-Pulley Cord System (a): Fixed 2:1 Reeving Ledger
Movable pulley systems with cord cut lifting force in half or more. Learn the mechanical advantage formula, real rigging examples, and design tradeoffs.
Horizontal Shaft to Two Vertical Shafts: Ideal Belt-Speed Ledger
How a single horizontal shaft drives two vertical shafts via crossed pulleys and a flat band — used in line shafting, mill drives, and overhead...
Plain Flat-Belt Pulley: Declared Crown Geometry
Plain flat-belt pulley design explained — crown geometry, tracking, slip, and sizing for industrial conveyors, line shafts, and machine drives.
Movable Pulley with Counterweight: Exact Balance and Travel Ratio
Explore an ideal counterweighted movable pulley. Calculate line tension, counterweight mass, two-to-one travel and load imbalance for two vertical supporting legs.
Single Movable Pulley: Ideal Rope Tension and Displacement Geometry
Calculate ideal rope tension, vertical force ratio and local load rise for a single movable pulley with symmetric rope segments. Includes an animated force model.
Modified Cone Pulleys: Exact Open-Belt Length
Compare four opposed stepped-pulley pairs and calculate exact ideal open-belt lengths and their spread at a shared shaft center distance.
Flanged Flat-Belt Pulley: Rim Width and Clearance | FIRGELLI
Understand flange spacing, belt width and side clearance. Includes a cross-section, simple width examples and the distinction between tracking and edge restraint.
Expanding Pulley: V-Groove Geometry Calculator | FIRGELLI
Explore opposed conical sheaves and calculate pitch-diameter change from axial closure and groove angle. This model covers one pulley rather than a full drive.
Detachable Chain Link: Spring-Clip Roller-Chain Assembly and Load Comparison
See how a spring-clip roller-chain connecting link assembles, and compare static tension in two strands with an assumed strength threshold.
Crossed Belt Drive Mechanism: How It Works, Diagram, Belt Length Formula, Parts and Uses
Explore crossed-belt geometry and opposite pulley rotation. Calculate ideal centerline length, speed ratio, wrap angle and center-distance-to-width ratio.
Concave-grooved Pulley for Round Band: How It Works, Groove Sizing, Diagram & Uses
Explore a round belt in a concave pulley groove. Compare cord diameter, groove radius and depth in an enlarged section; belt motion is illustrative.
Chain and Pulley (form 1) Mechanism Explained: How It Works, Diagram, Parts and Uses
See alternating-plane chain links engage a toothed wheel. Separately compare a load with hand pull to calculate the overall force ratio a complete system would...
Belt with Movable Tightening Pulley: How It Works, Parts, Formula, and Uses Explained
Explore a movable backside idler and compare ball-bearing basic rating life at two equivalent loads, with the same bearing and speed. Spring sizing is not...