Engineering lab · Interactive tool
Four-Bar Linkage Explorer.
Explore link proportions, open and crossed assembly branches, position closure, and output geometry for a planar four-bar mechanism.
Planar mechanism position closure
Live calculationr₂ + r₃ = r₁ + r₄Four-bar results updated. The open branch closes. Output angle 75.52 degrees. Transmission angle 51.25 degrees.
- a: input link
- b: coupler
- c: output link
- d: ground link
- θ₂: input angle
- Reference length set: Grashof classification
- Open and crossed assembly branches both close
Added visible variables, two verification examples, and an experience connection. Calculation method is unchanged.
Related engineering capabilityPosition closure is the first gate
The live diagram solves the intersection of the coupler and output-link circles at the selected input angle. Grashof classification describes the link-length set; it does not guarantee unrestricted rotation for every grounded-link choice or a useful mechanism.
A complete mechanism design must also control branch and circuit behavior, transmission angle, singularities, packaging, joint reactions, bearing life, tolerance sensitivity, stiffness, inertia, and interference through the intended motion.
Before committing a linkage
- Sweep the entire required input range on the intended assembly branch
- Confirm no order, branch, or circuit defect enters the operating range
- Check minimum transmission angle and mechanical advantage
- Model joint clearance and dimensional variation
- Evaluate collisions, hard stops, and actuator packaging
- Resolve dynamic loads, balance, fatigue, wear, and lubrication
Direct conversation
Review the product, the available evidence, and the decision blocking progress.
Send a concise, non-confidential brief. You will work directly with Jared from the first review through final handoff.
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