Patent ID: 7577494

Claim:
A variable vacuum control system, comprising: a vacuum source and an air source; a movable suction cup coupled to the vacuum source and an air source for periodically grabbing and removing a flat item from a bottom of a stack of flat items held in a hopper positioned above the suction cup by means of vacuum suction, the hopper having a slanted bottom wall and a front wall with a jogger which moves backward and forward to keep the flat items aligned in the hopper; a variable speed rotating drum for receiving each fiat item after removal, the drum moving at a variable speed relative to the hopper; at least one sensor/encoder associated with the drum for sensing the speed and position of the drum relative to the hopper and generating speed and position signals corresponding thereto; and a servo drive coupled to the sensor/encoder to control at least one vacuum/air valve, whereby, upon detecting a change in speed of the drum, the servo drive automatically alters control signals to the valve to alter the application of vacuum and air to the suction cup corresponding to the change in speed of the drum.