In the world of mechanical power transmission, gear drives have a very special and prominent place. This is actually the most preferred technology if you want to transmit significant power over a short distance with a 
constant velocity ratio. The mechanism of equipment drives is fairly simple – one’s teeth, which are cut on the blanks of the apparatus wheel, mesh with one another to transmit power. To avoid slipping, the projections on one disc mesh with the recesses on additional disc in gear drives.
This technology uses various kinds of gears for power transmission. In fact, it could transmit power not merely gear chain china between parallel shafts, but also between nonparallel, co-planar, and intersecting etc. shafts.