brake wheel

(in a windmill) a bevel gearwheel rotating with the wind shaft.

Origin of brake wheel

An Americanism dating back to 1870–75

Another element sometimes employed in arc-lamp mechanism is the brake-wheel regulator.

Encyclopaedia Britannica, 11th Edition, Volume 16, Slice 6 |Various
He had to clutch the brake-wheel to keep himself from falling.

King Spruce, A Novel |Holman Day
The fireman had already seen the danger, and sprung to the brake-wheel on the tender behind him.

Campmates |Kirk Munroe
Si walked to the end of the car, tore off the brake-wheel, and came back.

Si Klegg, Book 2 (of 6) |John McElroy

He turned then to the brake-wheel, but, before he could apply it, Thomson had risen and grappled with him.

The Iron Horse |R.M. Ballantyne