| 摘要 |
An inexpensive paper folding machine includes a paper feeder that reliably propels sheets one at a time in a downstream direction. The feeder includes a paper supply station that biases a stack of sheets against a pickoff wheel. The pickoff wheel propels the topmost sheet to a gate tip. The gate tip is comprised of a singulator that is biased against the pickoff wheel. A clearance is set between a singulator screw and the singulator. The clearance is greater than the sheet thickness, but less than two times the sheet thickness. As a sheet is propelled by the pickoff wheel from the paper supply station, the sheet leading edge enters the nip between the pickoff wheel and the singulator. The singulator pivots to take up part of the clearance. If a second sheet is propelled with the topmost sheet, the second sheet cannot pass between the nip. The paper folding machine further comprises a skew compensator that compensates for sheets that are misoriented relative to the downstream direction. In a modified embodiment, a relatively soft pickoff wheel is used, and the clearance is less than the thickness of a sheet. The pickoff wheel is compressed as the sheet passes through the nip between the singulator and the pickoff wheel.
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