pitch circle

American  

noun

Machinery.

1. an imaginary circle within the profiles of the teeth of a gear, such that it rotates against a similar circle rotating at the same rate on a meshing gear.

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pitch circle British  

noun

1. an imaginary circle passing through the teeth of a gearwheel, concentric with the gearwheel, and having a radius that would enable it to be in contact with a similar circle around a mating gearwheel

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Etymology

Origin of pitch circle

First recorded in 1810–20

Example Sentences

See Examples For:

pitch circle

The arc pitch multiplied by the number of teeth in the wheel gives the circumference of the pitch circle.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua

The requirement of thickness is necessary because the difference between the arc and the chord pitch is greater in proportion as the diameter of the base or pitch circle is decreased.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua

The flank of each wheel is struck with a tracing point, thus attached to the pitch circle of the other wheel.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua

Then, diameter of addendum circle 19.943 inches less 1.8 inches = 18.143 inches, which is the diameter of the pitch circle.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua

The diameter of a gear-wheel is always taken at the pitch circle, unless otherwise specially stated as “diameter over all,” “diameter of addendum,” or “diameter at root of teeth,” &c., &c.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua