Sheet feeding apparatus

Claim 1

In an oscillating vacuum feeder for feeding sheets seriatim from a sheet stack along a sheet travel path, said oscillating vacuum feeder including a tubular housing having at least one port through the wall of said housing, means for oscillating said tubular housing along said sheet travel path between a first position wherein said one port is located adjacent to said sheet stack and a second position remote from said first position, and wherein a sheet is tacked to said tubular housing by pneumatic forces created by a vacuum applied to the inside of said tubular housing when said tubular housing is in said first position, whereby during at least a portion of the oscillating movement of said tubular housing from the first position to its second position, the tacked sheet is moved along said travel path, and a vacuum vent port located through the wall of said housing, a control valve operatively associated with said vacuum vent port, said control valve comprising: a movable valve shoe mounted on said tubular housing for opening and closing said vacuum vent port; means for resiliently urging said valve shoe to a first position in which said vacuum vent port is closed; linkage means for moving said valve shoe to a second position in which said vacuum vent port is open; and control means for actuating said linkage means to open the vent port and relieve the vacuum within said tubular housing during the movement of said housing from said second position to said first position, thereby releasing the tacked sheet for further movement along said sheet travel path.