Origin of worm gear
Examples from the Web for worm gear
The frame e carries the worm-wheel a and the worm-gear b, which is operated by the crank f.
In this case the worm-gear pinion is on the side of the machine not seen in the engraving.
The worm-gear is forced tightly on the taper spindle with a nut, and keyed to prevent turning.
In removing it from the box, pick it up by placing the hands underneath the worm-gear.The Gunner's Examiner|Harold E. Cloke