Abstract: A high speed machine that inserts about twelve thousand sheets or stacks of sheets of paper per hour into the same number of envelopes. A first table delivers an elongate horizontal queue of thousands of envelopes to an envelope hopper. A second table, parallel to the first table, includes a plurality of independently-controllable sheet feeders and delivers individual groups of stacked sheets to an envelope insertion station that is transversely spaced apart from the envelope hopper. A third table is disposed transversely to the first two tables and includes the envelope insertion station. Clamps carried by an elongate sprocket chain mounted in the third table sequentially remove envelopes from the bottom of the envelope hopper and pull them past an envelope flap-opening structure to the envelope insertion station where the envelopes are opened by a puff of air.

Abstract: A feeder for sheets of material has belts for driving sheets through the feeder, and a gate above the belts to hold back the stack of sheets to be fed. The gate is elliptical in side elevational view and flat in front and rear elevational views. The major axis of the ellipse is disposed at an acute angle to the feed path, so sheets waiting to be fed engage the large-radius portion of the ellipse and are shingled just before reaching the position to be fed. The wide, flat surface has O-rings of rubber or the like to provide a high coefficient of friction for retarding the stack of sheets to be fed. A sensor detects a sheet that has been fed, and stops the feeder, so the feeder can be used as an on-demand feeder.

Abstract: The feed table of a paper folder is provided with a downward step at the discharge end of the feed table. The downward step provides a discharge area so that the leading edge of a sheet can be pulled forward and down for a positive feed without wrinkling the leading edge through contact with the feed table. A vacuum wheel engages and holds the paper to effect the feed, and the vacuum wheel has an increased number of holes for a stronger grip. The rear ends of paper guides are movable by screws for carefully controlled skewing of the paper with respect to the feed table.

Abstract: A quarter-folder operates at high speed by reducing the leading edge to leading edge distance between successive papers, and continuing to move the papers forward while urging the papers down between folding rolls. The folding rolls are obliquely disposed so that a tucking blade urges a portion of the paper between the rolls, and the angular disposition causes the paper to continue. A plurality of pairs of folding rolls receives a paper for complete folding. Retarding brush rollers will slow the folded paper to be received by a conventional creel.