Law of Belting:

The law of belting states that the centre line of the belt like it approaches the pulley, ought to be lie in plane perpendicular to the axis of the pulley in the mid plane of the pulley or else the belt will run off the pulley. But, the point at which the belt leaves the other pulley ought to lie in the plane of a pulley.

The given Figure below illustrates the belt drive in which two pulleys are at right angle to each other. It may be seen that the centre line of the belt approaching larger or smaller pulley lies in its plane. The point at which the belt leaves is contained in the plane of the other pulley.

If motion of the belt is reversed, the law of the belting shall be violated. Thus, motion is possible in one direction in case of non-parallel shafts as illustrated in Figure.