UNIVERSAL JOINT

To couple two shafts in different planes, you need to use a universal joint. Universal joints have various forms. They are used in nearly all types and classes of machinery. An elementary universal joint, sometimes called a Hooke joint consists of two U-shaped yokes fastened to the ends of the shafts to be connected. Within these yokes is a cross-shaped part that holds the yokes together and allows each yoke to bend, or pivot, in relation to the other. With this arrangement, one shaft can drive the other even though the angle between the two is as great as 25° from alignment.
It is merely a slight modification of the old Hooke joint. Automobile drive shaft systems use two, and sometimes three, of these joints. 

The Bendix-Weiss universal joint provides smoother torque transmission but less structural strength. In this type of joint, four large balls transmit the rotary force, with a smaller ball as a spacer. With the Hooke type universal joint, a whipping motion occurs as the shafts rotate. The amount of whip depends on the degree of shaft misalignment. The Bendix-Weiss joint does not have this disadvantage; it transmits rotary motion with a constant angular velocity. However, this type of joint is both more expensive to manufacture and of less strength than the Hooke type.