Hi, I am designing a vibrating platform that will move strictly up and down (total displacement of 1 inch). The load on the platform will vary between 0 and 160kg. The mechanical assembly/mechanism (which is underneath the platform) is motor>belt>flywheel>crank attached to a 1 inch shaft long that is off center of the flywheel which is then attached to the flat platform. The square platform is have 4 vertical rods through its corners with linear plain bearings. Take a look at the slider crank http://functionspace.com/topic/3704/Converting-Rotational-motion-to-Linear-motion-and-vice-versa I need to find out how to spec the motor (torque,HP). Is this mechanical assembly the right application for a vibrating platform? When the crank reaches the bottom of the circular motion (dead point) would it not have two ways of moving resulting in a potential failure?