| 摘要 |
A system for measuring the friction between the bottom two sheets of the stack. The bottom-most sheet is held to a vacuum corrugation feeder tray by any suitable means such as a vacuum and moves with the tray. The vacuum corrugation feeder tray is mounted on compliant supports and driven near or at its resonant frequency by an electromechanical driver. At low or zero air knife pressure, the paper stack is mechanically coupled to the tray and moves with the tray, possibly slipping at some point during the vibration cycle. As the air knife pressure increases, the mechanical coupling decreases, and a point is reached at which the stack remains stationary. Prior to the point where stack motion ceases, the resonance of the tray is modified and it is possible to estimate the weight of the stack. When the stack motion ceases, the frictional force F can be estimated from the driving force required to maintain a given vibrational amplitude. From the driving force required to maintain a given vibrational amplitude and the mass of the tray or stack, it is possible to calculate the coefficient of friction between the bottom two sheets. The coefficient of friction is then used to control the amount of air pressure from the air knife until an optimum coefficient of friction is achieved. |
