Compare the toothed and locking portions of an intermittent-gear cycle as percentages of their combined angle. The schematic illustrates alternating advance and dwell; the two entered angles do not determine gear teeth, output travel or working lock geometry.
Intermittent Gears Interactive Calculator
Explore normalized toothed-segment and locking-segment shares while checking whether their entered total represents one full revolution.
Equation Used
- Toothed and locking inputs are nonoverlapping positive angular segments expressed on one common reference.
- Only when their sum is 360 degrees are they interpreted as covering one complete driver revolution.
- Driver speed is assumed uniform when angular shares are informally read as time shares.
- No module/pitch, tooth count/profile, centre distance, follower geometry, locking-face geometry, index angle, entry/exit modification, interference, backlash, contact ratio, acceleration, torque, stress, wear, lubrication, manufacturing or safety model.
For a single physical driver revolution, toothed arc plus locking arc must equal 360 degrees. Other totals are still valid ratio arithmetic but do not define a complete circular gear. The displayed 45-degree index, tooth counts, pitch geometry and lock clearances are illustrative because those quantities are not entered.
Alternating advance and dwell
The page divides each entered segment by their sum. Under constant driver speed, those angular shares equal corresponding time shares.
The animation shows a partial-tooth driver advancing a full driven gear during the toothed phase, followed by a stationary output while an illustrative locking ring and follower pocket identify the dwell relationship. The 45-degree output step is deliberately labeled illustrative because tooth pitch, follower displacement and locking geometry are absent.
Compare the two angular segments
The ratios can check a proposed split between two already-defined cycle segments. They cannot determine output index angle, produce a gear drawing, establish locking, or predict speed, precision and life.
The total-angle check matters
Motion share=At/(At+Al), dwell share=Al/(At+Al), and their sum is 100%. Locking-to-toothed ratio is Al/At.
A complete circular driver requires At+Al=360 degrees. If the total differs, the outputs remain normalized arithmetic only.
Worked example
For entered segments 120 and 240 degrees, total is 360 degrees, normalized shares are 33.33% and 66.67%, and locking/toothed ratio is 2:1. This still does not establish compatible teeth, follower travel or locking faces.
What determines a working gear pair
A working gear pair needs compatible tooth pitch and profiles, center spacing, entry and exit geometry, and a lock that clears during indexing. Those dimensions also determine the output step. Loads, inertia, backlash and material strength require separate checks; the segment percentages alone do not establish them.
Questions
Does a 360-degree total prove the mechanism is feasible?
No. It only closes the driver's circumference.
Does motion share give follower rotation?
No. Gear ratio and actual engaged tooth geometry are absent; the displayed step is illustrative.
Can the result predict dwell accuracy?
No. Lock geometry, clearance, wear, compliance and loads are not modeled.
Further reading
Carnegie Mellon University’s Introduction to Mechanisms, section 8.3, describes intermittent gearing in which a toothed portion advances the follower and a locking feature holds it during the remaining driver rotation. The example’s specific teeth and 40° advance differ from this page’s illustrative 45° step.
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