Sheet feed device for leaflet folder

An apparatus adapted to be used for the automatic handling of sheets from which leaflets are formed, said apparatus comprising:

• a transfer unit for conveying sheets;
• an accumulator station disposed adjacent said transfer unit, said accumulator station being adapted to receive sheets from said transfer unit and to accumulate said sheets in a stack;
• a sensor associated with said accumulator station, said sensor being adapted to generate a signal indicative of whether the height of said stack of sheets in said accumulator station is at least a minimum height;
• a sheet feeder being adapted to periodically remove sheets from said stack of sheets, said sheet feeder being adapted to remove sheets from said stack of sheets at a substantially constant rate, said sheet feeder comprising:
• a rotatable vacuum roll adapted to remove a sheet from the bottom of said stack of sheets at said accumulator station;
• a vacuum generator operatively coupled to said vacuum roll for creating a suction pressure within an interior portion of said vacuum roll;
• and
• a motor for causing said vacuum roll to be rotatably driven at a substantially constant rate;
• and
• a control mechanism operatively coupled to said sensor and said sheet feeder, said control mechanism being adapted to cause said sheet feeder to remove said sheets from said accumulator station as long as the height of said stack of sheets is at least said minimum height as determined by said sensor, said control mechanism being adapted to cause said sheet feeder to cease removal of said sheets from said accumulator station if the height of said stack of sheets falls below said minimum height as determined by said sensor,
• said control mechanism comprising an actuator mechanism operatively coupled to said vacuum generator that selectively eliminates said suction pressure, in response to said signal generated by said sensor, while said vacuum roll is being rotatably driven by said motor.

An apparatus adapted to be used for the automatic handling of sheets from which leaflets are formed, said apparatus comprising:

• a transfer unit for conveying sheets;
• an accumulator station disposed adjacent said transfer unit, said accumulator station being adapted to receive sheets from said transfer unit and to accumulate said sheets in a stack;
• a sensor associated with said accumulator station, said sensor being adapted to generate a signal indicative of whether the height of said stack of sheets in said accumulator station is at least a minimum height;
• a sheet feeder being adapted to periodically remove sheets from said stack of sheets, said sheet feeder comprising:
• a rotatable vacuum roll adapted to remove a sheet from the bottom of said stack of sheets at said accumulator station;
• a vacuum generator operatively coupled to said vacuum roll for creating a suction pressure within an interior portion of said vacuum roll;
• and
• a motor for causing said vacuum roll to be rotatably driven;
• and
• a control mechanism operatively coupled to said sensor and said sheet feeder, said control mechanism being adapted to cause said sheet feeder to remove said sheets from said accumulator station as long as the height of said stack of sheets is at least said minimum height as determined by said sensor, said control mechanism being adapted to cause said sheet feeder to cease removal of said sheets from said accumulator station if the height of said stack of sheets falls below said minimum height as determined by said sensor.