Separation and Transportation of Works Using Elliptical Vibration (Separation by Gap Length in Contact Surface)

When elliptical vibration with vertical vibration over the jump limit is given, works on a vibration table move right or left depending on whether they jump or not, and the works can be separated and transported. We investigated the phenomenon by which some works jump and others do not when there is vertical vibration over the jump limit. First, the pressure fluctuation produced in the contact surface between a work and a vibration table was measured. The negative pressure produced in the contact surface suppresses the jump of the work. It was then shown that the negative pressure was derived from the viscous damping which changes depending on the gap length in the contact surface. The gap dependence of viscous damping limits the generation of the negative pressure and produces the jump. Finally, the difference in the generating limit of the negative pressure was used to separate the works by the gap length.