Ratchet indexing and tooth load calculator

Ideal tooth-index travel per stroke; no engagement dynamics.

linkages-ratchet.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	incrementdeg	totalRotationdeg
	15	900
	18.9474	1136.84

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

stroke increment budget15.00 deg✓ passes

BASELINE INPUTS

teeth24 teethPerStroke1 strokes60

CALCULATED

increment15 deg

totalRotation900 deg

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Ratchet indexing and tooth load
# Scope: Ideal tooth-index travel per stroke; no engagement dynamics.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

teeth = 24
teethPerStroke = 1
strokes = 60

increment := 2*pi*teethPerStroke/teeth [deg]
totalRotation := increment*strokes [deg]

check stroke increment budget: increment <= 20 deg

scenario alternative: teeth = 19

Calculated from your source · not saved

Baseline · Baseline

stroke increment budget15.00 deg ✓ passes

alternative · alternative

stroke increment budget18.95 deg ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

increment: increment = 2*pi*teethPerStroke/teeth [deg]
total rotation: totalRotation = increment*strokes [deg]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

teeth: 24
teeth per stroke: 1
strokes: 60

Calculated

increment: 15 deg
total rotation: 900 deg

Assumptions and limits

Ideal tooth-index travel per stroke; no engagement dynamics.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Ratchet indexing and tooth load. Inputs: tooth count; lever stroke; torque. Outputs: index increment; pawl load. Model scope: Planar rigid-link geometry with explicit joints and branches. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: tooth count, lever stroke, torque
Outputs: index increment, pawl load
Modes: calculate, compare, sweep
Drawing: Interactive linkage

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS