GEAR BOX OR TRANSMISSION

Transmission word is generally used for gear box. Transmission is a mechanism which provides us variation in speed and torque as required. The transmission may be gear box or automatic.

SLIDING MASH GEAR BOX
Construction there is a gear called clutch gear which is mounted on a clutch shaft. The clutch gear A is always attached with lay shaft gear D. the lay shaft gear is always mounted on a shaft which is called lay shaft. There are three other gears E, F, and G, fixed on the lay shaft. There is also an ideal shaft on which a small ideal gear H is mounted this ideal gear is used for reversing the direction. There is a main shaft which is aligned to the clutch shaft. Two gears B and C are mounted on the shaft.  Working no power is transmitted to main shaft when gear box is in neutral position First gear: the gear C is slide on main shaft such that it is meshed with gear F. now the main shaft starts rotating.                   

The power transmitted from the clutch shaft through gears A, D, F, and C to the main shaft.
 
Second gear: the gear B is slide on main shaft such that it is meshed with gear E. The power transmitted from the clutch shaft through gears A, D, E, and B to the main shaft.
 
High gear or top gear: the gear B is slide on main shaft such that it is directly engaged with gear A through splines. So the power is transmitted to main shaft directly without reduction.
 

Reverse gear: the gear C is slide on the main shaft such that it is meshed with the idle gear H reverse the direction of rotation of main shaft. In this position power is transmitted from clutch shaft through gear A, D, G, H and C to main shaft.