None.

Spiral gear is used connect two non parallel and non intersecting shafts. Spur gear is used to connect two parallel and coplanar shafts.

The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc.

Rack and pinion gears are used to convert rotation into linear motion. The flat, toothed part is the rack and the gear is the pinion. A piston coaxial to the rack provides hydraulic assistance force, and an open centered rotary valve controls the assist level.

When the axes of the first gear (i.e. first driver) and the last gear (i.e. last driven or follower) are co-axial, then the gear train is known as reverted gear train.

The epicyclic gear trains are useful for transmitting high velocity ratios with gears of moderate size in a comparatively lesser space. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc.

The distance measured along the pitch circle from a point on one tooth to the corresponding point on an adjacent tooth is called circular pitch.

None.

N1 = 200

Spiral gear is used connect two non parallel and non intersecting shafts. Spur gear is used to connect two parallel and coplanar shafts.