In the world of mechanical power 
transmission, gear drives employ a special and prominent place. This is actually the the majority of preferred technology if you want to transmit substantial power over a short distance with a continuous velocity ratio. The system of equipment drives is fairly simple – the teeth, which are cut on the blanks of the gear wheel, mesh with one another to transmit power. In order to avoid slipping, the projections on one disc mesh with the gear chain china recesses on additional disc in gear drives.
This technology uses different types of gears for power transmission. In fact, it can transmit power not merely between parallel shafts, but also between nonparallel, co-planar, and intersecting etc. shafts.