The two inputs define a selected angular ledger only. Their ratio gives a constant-input-speed time ratio, while their sum must equal 360° to describe one closed input revolution. Ellipse axes, orientation, pivot location and output linkage are absent, so this calculator does not derive an elliptical pin orbit or slotted-lever motion.
Elliptical-Pin Slotted Crank · Selected Angle Ledger
Compare two selected input-angle intervals on a common scale and check whether they close one 360° revolution.
Equation Used
- Input speed is constant when interpreting the selected angle ratio as a time ratio.
- The selected intervals are independent and are not silently normalized to 360 degrees.
- A closed one-revolution schedule requires slow plus return to equal 360 degrees.
- Ellipse axes, orbit orientation, pivot geometry, output linkage, loads, wear, strength and safety are excluded.
Independent inputs are preserved. A zero closure difference is required for a one-revolution schedule.
Selected angular ledger
The visualization places the selected slow and return intervals on one common degree scale. A 360° reference and signed cycle-closure difference expose whether the pair closes one shaft revolution without silently normalizing either input.
What the calculator determines
Select two angular intervals. The calculator reports their direct ratio, each interval's share of the selected total and the signed difference 360°−(slow+fast).
Exact selected-angle arithmetic
R=θslow/θfast; shares=100θ/(θslow+θfast); closure=360°−θslow−θfast.
Selected-input example
For 200° and 160°, the ledger closes exactly, the ratio is 1.25:1 and the shares are 55.56% and 44.44%.
Not a mechanism synthesis
The selected angle pair does not determine ellipse axes, eccentric gearing, orbit orientation, frame pivot, slot length, lever output or reversal positions. Velocity, dwell, force, load, wear, strength and safety are excluded.
Questions
Why is no ellipse drawn?
No ellipse dimensions or pivot geometry are supplied, and many different mechanisms could share the same selected time ratio.
Why can the closure value be nonzero?
The controls are independent. The calculator preserves both selections and exposes their mismatch instead of changing them.
References
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