Inventors:
Gene F. Croyle - Plano TX
E. Lennart Lindstedt - Richardson TX
Frederick N. Mueller - McKinney TX
Assignee:
Levi Strauss & Co. - San Francisco CA
International Classification:
B65H 508
Abstract:
A sheet feeder includes a pneumatic picker for picking the top sheet from a stack of sheets, and a flipper for inverting upside-down sheets. The picker has a row of suction cups, supplied with vacuum through hoses, for picking up the top sheet. The lip of each suction cup is inclined to the top surface of the stack at a fixed angle. If the angle is properly chosen, exactly one sheet will be picked up as the picker is moved onto and away from the stack. The inclined suction cups are for permeable materials such as cloth. The picked sheet may be inverted by a twisted-belt flipper if needed. The flipper has four rollers with axes in a rectangular configuration, and two twisted belts. Each belt is wrapped around a pair of rollers on opposite corners of the rectangle, and the belts run closely in between the far pairs. A sheet will be flipped as it travels through, held between the two belts. To select which sheets are to be flipped, a photocell and gate work to direct sheets into or around the flipper.