Select Linkage Type
Choose the type of mechanism to analyze:
Four-Bar Linkage Parameters
Drag the joints in the visualization below to adjust the linkage, or enter values manually. The calculator will analyze the mechanism in real-time.
Interactive Linkage Visualization
Drag any joint (including ground points) to modify the linkage configuration
Linkage Analysis Results
Linkage Mechanisms Reference
Four-Bar Linkage
The simplest movable closed-chain linkage with four rigid links connected by four revolute joints.
- Ground Link: Fixed base
- Input Link (Crank): Driver
- Coupler: Floating link
- Output Link (Rocker): Follower
Applications: Door closers, automotive suspension, robotic arms
Slider-Crank Mechanism
Converts rotary motion to reciprocating motion (or vice versa). Used in engines and pumps.
- Crank: Rotating input link
- Connecting Rod: Coupler link
- Slider: Translating output
Applications: Internal combustion engines, reciprocating pumps, compressors
Six-Bar Linkages
Watt Linkage: Two four-bar chains sharing a common link. Produces approximate straight-line motion.
Stephenson Linkage: Two four-bar chains with one binary link in common. More complex motion patterns.
Applications: Automotive suspension (Watt's linkage), walking machines, complex path generation
Quick Return Mechanism
Produces different speeds for forward and return strokes. Essential for manufacturing processes.
- Working Stroke: Slower motion
- Return Stroke: Faster motion
- Time Ratio: Determines efficiency
Applications: Shapers, slotting machines, metal cutting operations
Grashof's Criterion
s + l ≤ p + q
where s = shortest, l = longest, p & q = intermediate links
- Grashof: At least one link rotates 360°
- Crank-Rocker: Shortest is input crank
- Double-Crank: Shortest is ground
- Double-Rocker: Shortest is coupler
- Non-Grashof: All links rock/oscillate
Coupler Curves
Path traced by a point on the coupler link. Can create:
- Straight Lines: Watt, Chebyshev, Peaucellier
- Figure-8 Patterns: Complex motions
- Elliptical Paths: Approximate circles
- Custom Paths: For specific applications
Uses: Walking mechanisms, manufacturing paths, straight-line guidance
Design Considerations
- Transmission Angle: 40°-140° ideal for efficiency
- Dead Points: Positions where motion stops
- Mechanical Advantage: Force multiplication
- Link Ratios: Affect speed and torque
- Singularities: Avoid collinear configurations
Common Applications
- Automotive suspension and steering
- Engine valve trains and pistons
- Industrial machinery and presses
- Door and window mechanisms
- Aircraft landing gear
- Robotic manipulators
- Bicycle and vehicle transmissions
- Walking and climbing robots