A worm turns the wheel connected to a winch drum. The reduction makes the drum turn more slowly than the crank. Enter wheel teeth, worm starts and crank turns to calculate the ideal drum rotation.
Worm-gear Winch Interactive Calculator
Enter wheel tooth count, worm starts and crank turns. Compare reduction ratio, wheel teeth advanced, drum revolutions and drum rotation per crank turn.
Equation Used
- Inputs are user-supplied scenario values.
- The displayed equations are evaluated directly.
- Entered efficiencies, shares, limits and factors are not predicted.
- The visual is schematic and not dimensional.
- Strength, fatigue, wear, variation, controls and safety compliance are omitted unless explicitly calculated.
How the Worm-gear Winch Works
Each revolution of the worm advances the wheel by the number of worm starts. The wheel and drum turn together in this schematic. The calculation describes rotation, not lifting force or rope travel.
What This Calculator Represents
This is an ideal indexing calculation. It does not calculate drum diameter, rope travel, lifting force, friction, braking, self-locking or working-load limit.
Calculation Method
Reduction ratio = wheel teeth / worm starts. Wheel teeth advanced = crank turns × worm starts. Drum revolutions = crank turns / reduction ratio. Drum rotation per crank turn, as a percentage of one revolution, = 100% / reduction ratio.
How to Read the Result
Change one input at a time to compare its effect. Apply the assumptions stated beside the equations when interpreting each result.
Assumptions and Limits
This is an ideal indexing calculation. It does not calculate drum diameter, rope travel, lifting force, friction, braking, self-locking or working-load limit.
Frequently Asked Questions
Does the ratio tell me whether the winch is self-locking?
No. Self-locking and load holding depend on details and conditions not included in this rotation calculator. Use the rated winch and brake specifications.
Does the calculator give rope travel?
No. It reports drum rotation. Rope travel also depends on drum diameter and the effective radius of the rope layers.
Is the drawing suitable for manufacturing?
No. It is a schematic explanation and does not specify manufacturing dimensions, tolerances or materials.
Can these results establish a safe working load?
No. Strength, fatigue, wear, operating conditions and the complete assembly must be assessed separately.
References
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