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

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 diameter of the pitch circle cannot be obtained from that of the addendum circle unless the pitch of the teeth and the proportion of the pitch allowed for the addendum be known.

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

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

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

Thus there will be upon the wheel face three circles, p p the pitch circle, j j wherefrom to mark the face curves, and i wherefrom to mark the flank curves.

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

Draw the radial line l, meeting the pitch circle at a.

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