A hand-chain hoist combines a reduction drive with supporting chain falls to reduce the pull needed to raise a load. This schematic shows the drive, pawls and load chain; the calculator compares an entered mechanical advantage and efficiency.
Yale Duplex Hoist Interactive Calculator
Enter load, assumed gear ratio, number of supporting chain falls and efficiency. Compare ideal and efficiency-adjusted mechanical advantage, hand pull and load per fall.
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 Yale Duplex Hoist Works
Input motion passes through the reduction drive to the load chain. The supporting falls share the suspended load in the ideal model. The illustration does not determine brake performance or a rated lifting capacity.
What This Calculator Represents
The gear-ratio input is treated as a force-multiplication factor. Actual hand-wheel and load-wheel radii, friction, brakes, chain strength, dynamics and working-load limit are not calculated. Efficiency is an assumption, not a hoist test result.
Calculation Method
Load in lbf = entered short tons × 2000. Ideal mechanical advantage = entered gear ratio × chain falls. Effective mechanical advantage = ideal advantage × entered efficiency. Hand pull = load / effective advantage. Ideal load per fall = load / chain falls.
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
The gear-ratio input is treated as a force-multiplication factor. Actual hand-wheel and load-wheel radii, friction, brakes, chain strength, dynamics and working-load limit are not calculated. Efficiency is an assumption, not a hoist test result.
Frequently Asked Questions
Does the calculated hand pull establish a load rating?
No. It estimates effort using your entered ratios and efficiency. A load rating also depends on the complete hoist, chain, brake, hooks and support.
Does the gear-ratio input include the hand-wheel and load-wheel radii?
No separate wheel radii are entered. The model treats the supplied ratio as a force-multiplication factor, so it does not reproduce every hoist drive.
Is the drawing suitable for manufacturing?
No. It is a schematic explanation and does not specify manufacturing dimensions, tolerances or materials.
Do these results establish safe operating limits?
No. Assess the complete equipment, loads, materials, controls and applicable requirements separately.
References
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