초록 ▼

A vacuum shingler for a plurality of sheets (9) traveling in succession through an upstream infeed nip (13) is provided with a vacuum modulating control which applies sheet slow-down forces primarily to only the tail ends of the sheets. In one embodiment, the control provides a substantially “on-off

A vacuum shingler for a plurality of sheets (9) traveling in succession through an upstream infeed nip (13) is provided with a vacuum modulating control which applies sheet slow-down forces primarily to only the tail ends of the sheets. In one embodiment, the control provides a substantially “on-off”vacuum operation, with the vacuum “off”when the leading end portion of the sheet is adjacent the vacuum plenum opening(s) (39), and with the vacuum “on”when the tail end portion of the sheet is adjacent the opening(s). In another embodiment, the control modulates the vacuum so that it is at a basically unshingling low or reduced level when the leading end portion of the sheet is adjacent the opening(s), and is at a substantially increased high level when the tail end portion of the sheet is adjacent the opening(s) so that basic shingling occurs. The vacuum modulating control includes devices (12, 63) for sensing the position, speed and length of the traveling sheets, with this information being processed to provide an output signal which controls the speed of a shaft (52) with which a rotary valve is associated. The valve is disposed within the vacuum shingler plenum (34) and modulates the flow of air through the plenum opening(s) in correlation with the determined information. The vacuum shingler assembly is disposed so that its sheet input is substantially horizontally aligned with the discharge of the infeed nip (13). Furthermore, the assembly is disposed with its conveyor portions (28) generally horizontal, rather than inclined, so that even the middle of a sheet is supported thereby as the sheet spans the conveyor.

대표청구항 ▼

In a device for shingling individual sheets conveyed in succession upstream-to-downstream and with said sheets having downstream forward end portions and upstream trailing end portions, the combination comprising: (a) a shingler plenum (34) having walls (35-37) forming a plenum chamber (56), (b) mea

In a device for shingling individual sheets conveyed in succession upstream-to-downstream and with said sheets having downstream forward end portions and upstream trailing end portions, the combination comprising: (a) a shingler plenum (34) having walls (35-37) forming a plenum chamber (56), (b) means (38) connecting said plenum to a source of vacuum, (c) opening means (39) disposed in a wall of said plenum for passage of vacuum air therethrough into said chamber, (d) a shingler conveyor (28) disposed adjacent said plenum and said opening means for carrying the traveling sheets thereacross for shingling the latter under the grabbing force of said vacuum, (e) and means (52) for alternately modulating the application of said vacuum through said opening means to said traveling sheets so that the forward end sheet portions are essentially free of sheet grabbing vacuum forces and so that the trailing end sheet portions are subject to working sheet grabbing vacuum forces, (f) the construction being such that delicate sheets are substantially prevented from buckling transversely as said sheets are shingled, (g) said vacuum modulating means including means for controlling the application of vacuum forces between a first vacuum level when said forward end sheet portions are passing across said opening means and a second vacuum level when said trailing end sheet portions are passing across said opening means, and with said second level being higher than said first level, (h) said opening means (39) including a plurality of openings (40-42), (i) and at least one of said openings (40) providing a vacuum air flow bypass means which is essentially unaffected by said vacuum modulating means.