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

Now as d drives p, therefore the velocity of p must at the pitch circle be the same as d, let the numbers of teeth in the respective wheels be what it may, and it follows that the velocities of o, e, d and p are at the pitch circles equal.

From Project Gutenberg

The velocity and power of gear wheels are calculated at the pitch circle.

From Project Gutenberg

From 1 to 6 are points of equal division on the pitch circle, and d to i are arc locations for the centre of the generating circle.

From Project Gutenberg

But since teeth with radial flanks are produced, as has been shown, with a generating circle equal in diameter to the radius of the pinion, and since with a generating circle bearing that ratio of diameter to diameter of pitch circle the acting part of the flank is limited, it is usual to fill in the corners with fillets or rounded corners, as shown in Fig.

From Project Gutenberg

The stud carrying g has journal bearing at f, and carries a pinion whose pitch circle is at h and which gears with the rack.

From Project Gutenberg