Final answer:
A Double Enveloping Worm Drive is a highly efficient gear mechanism used in various machinery, characterized by its curved worm and gear that provide a large contact area for improved torque and reduced friction.
Step-by-step explanation:
A Double Enveloping Worm Drive is a type of gear mechanism used in machinery. This specialized gear set is designed to provide high torque and reduce friction between the worm screw and the gear wheel. The double enveloping feature involves the curving of both the worm and the gear, which creates a larger contact area and allows for more efficient power transmission. This type of drive system is commonly used in applications where space is limited and high gear reductions are required, such as in heavy industrial equipment, lift systems, and precision tuners.