| 摘要 |
A gap cutting sheeter having controls to adjust the cutting position of the first and second flying shears relative to each other to set the gap size to a particular printed sheet. The downstream flying shear can be set up to cut the leading edge or the following edge of while the web is moving. When cutting the leading edge, a flexible flipper is provided just ahead of the flying shear to contact and push successive cut chips toward a vacuum chip removal system. Alternating vacuum removes the chips, and pulsing positive air pressure against the underside of a leading, trimmed edge guides it over the chip removal vacuum chamber to the downstream conveyor. A knockdown vane is provided just after the flying shear to press the leading edge of a cut signature against the downstream deck plate to prevent wrinkling of the cut signatures. Simple and rapid gap size adjustment is accomplished by electronically controlling the relative positions and speed of the first and second flying shears, the speed of the incoming web relative to the downstream speed of the cut signatures and the synchronized control of the high pressure fed vacuum chip removal system. In either embodiment, the important feature of the invention is the simple and rapid gap size adjustment which is made possible by electronically controlling and mechanically phasing the relative positions and speed of the first and second flying shears, the speed of the incoming web relative to the downstream speed of the cut sheets or signatures and the synchronized control of the high pressure fed, vacuum chip removal system.
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