How a Drive Shaft works

This demonstration unit consists of a  constant rpm electric motor and sixty  two sprockets on the drive shaft as well  as the input and output yokes when there  is no operating angle on the u-joint the  output yoke of the driven member.

 The  u-joint and the drive shaft all travel  together at a constant speed watch the  tape on these sprockets and listen to  the sound the card makes as the drive  shaft rotates at the same speed as the output yoke and you joint  when an operating angle is created at  the front end of the drive shaft the output of the u-joint no longer travels  in a perfect circle  instead it travels in an ellipse.

  This forces the drive shaft to speed up  and slow down to keep pace with the  rotation of the output yoke creating  torsional and inertial vibration watch  the tape and listen to the coin as the  output of the u-joint changes speeds so  does the drive shaft even though the  output yoke itself is maintaining

A  constant speed when the operating angles  on each end of the drive shaft are not  equal the non-uniform velocity is  transferred to the input yoke of the  driven member making the centerline's of  the driving and driven members parallel  will automatically make the you joint