Compare two entered angular segments and see how much their total exceeds or falls short of 360°. The schematic illustrates intermittent spur gearing, but the entered angles do not determine working teeth, output rotation or lock geometry.
Intermittent Motion of Spur Gear Interactive Calculator
Explore entered segment shares, their total and signed 360-degree closure error.
Equation Used
- Entered segments use the same angular reference and are intended to be nonoverlapping.
- Uniform driver speed is assumed only when angular shares are read as time shares.
- A complete reference revolution requires total=360 degrees.
- No module/DP, pressure angle, tooth count/profile, pitch radii, centre distance, follower displacement, locking plate/scallop, interference, backlash, dynamics, loads, strength, wear or safety model.
A zero closure error means only that the two entered segments cover one full reference revolution. It does not establish an integer tooth count, compatible driven-gear motion or feasible locking geometry.
Toothed and locking angle comparison
The two entered angles are summed, then each is divided by the total to produce normalized shares. Signed closure error is total−360 degrees.
The animation demonstrates a partial-tooth driver advancing a full driven gear and then holding it stationary during the locking phase. The displayed 60-degree step and lock geometry are illustrative because the inputs are insufficient to reconstruct tooth contact, pitch radii or a locking plate.
Check the total angular span
The outputs can catch an angular gap or overlap in a proposed pair of angular segments. They cannot specify output travel, tooth counts, dwell locking, speed, precision or capacity.
Interpret the sign
A positive closure error indicates entered segments exceed 360 degrees; a negative value indicates an unassigned angular gap. Zero means only that the entered angles sum to 360°.
At constant driver speed, normalized angular shares also equal idealized time shares. No input speed is provided, so no dwell time is calculated.
Worked example
For 90 degrees toothed and 270 degrees locking, total is 360 degrees, shares are 25% and 75%, and closure error is zero. Output step remains unknown because driven-gear tooth geometry is absent.
What a working mechanism requires
The driver and follower need compatible tooth geometry and a lock that holds during dwell while clearing during indexing. The number and spacing of engaged teeth determine output rotation. Actual loads, inertia, clearance and material strength require separate analysis; a 360° angle total does not establish any of them.
Questions
Does a zero closure error define a gear?
No. It only closes two entered angular segments.
Can motion percentage determine output angle?
No. Pitch radii and tooth engagement are absent; the displayed step is illustrative.
Does locking share prove the follower is held?
No. A validated locking plate/scallop geometry and load check are required.
Further reading
Carnegie Mellon University, Introduction to Mechanisms, section 8.3, explains how intermittent gearing combines follower advance with a locked rest interval. Its illustrated tooth arrangement is distinct from this page’s schematic 60° index.
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