worm gear and worm wheel

The arrangement of gears seen above is called a worm and worm wheel. The worm, which in this example is brown in colour, only has one tooth but it is worm gear and worm wheel similar to a screw thread. The worm wheel, coloured yellow, is like a standard equipment wheel or spur equipment. The worm at all times drives the worm wheel circular, it is never the opposite way circular as the system will lock and jam