Worm 1 rotates about fixed axis A-A and its threads a mesh with teeth b of worm wheel 2 which rotates about fixed axis B. The pitch surface of the worm is globoid, i.e. it is generated by the rotation of a circular arc whose radius equals the pitch radius of worm wheel 2 in a plane perpendicular to axis B and passing through axis A-A. The arc rotates about axis A-A. The transmission ratio of the mechanism is i₁₂=ω₁/ω₂=z₂/z₁ where ω₁ and ω₂ are the angular velocities of worm 1 and worm wheel 2, z₁ is the number of threads, or starts, on worm 1 and z₂ is the number of teeth on wheel 2. The mechanism is employed to transmit high torque and power.
$2808$WG,3L$