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.

---

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

---

Etymology

Origin of pitch circle

First recorded in 1810–20

Example Sentences

See Examples For:

pitch circle

Set the compasses to the radius r l, and from p, as a centre, draw the pitch circle k.

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

Divide on r, the distance between the pitch circle and the wheel centre, into four equal parts, by 1, 2, 3, &c.

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

But when the gearing is compounded the variation of velocity at the pitch circle, which is due to the compounding, has an important bearing upon the necessary strength of the teeth.

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

The depth below pitch line or the length of flank is, therefore, the distance between the pitch circle and the base circle.

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

It is obvious then that the generating circle is rolled within the pitch circle for the face of the wheel and without for its flank, or the reverse of the process for spur-wheels.

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