Worm and planetary gears work together to transfer rotational movement in one plane to another plane. The worm gear and planetary gear (also commonly referred to as a worm and worm gear, respectively) are placed in rotational engagement with each other so that the threads of the worm gear mesh with the teeth of the planetary gear. Thus, the longitudinal axis of the worm gear and that of the planetary gear are at right angles with each other so that rotational movement of one gear along its longitudinal axis is transferred to the other gear along its longitudinal axis.
The worm gear/planetary gear combination may be used to transfer the rotational movement of one shaft or other body to that of another shaft or body. This may be accomplished by coupling one of the shafts to the worm gear and the other to the planetary gear. Couplings are used to couple the shafts to the gears. In general, the couplings are separate elements, such as a nut or bearing, which must be separately attached to both the shaft and the gear. For example, the shaft may be inserted into the axle of the gear and held in place with a bearing.
The shafts coupled to the worm and planetary gears may by rotated manually. However, the gears can also be rotated by a motor. Thus, either the manual or motorized motion of one shaft is translated via the worm gear/planetary gear combination to another shaft or body.