The present invention relates to interfolding methods and apparatuses, and more specifically to the transfer of sheets onto interfolding rolls of the interfolding methods and apparatuses.
Various combinations and types of rolls can be present in an interfolding apparatus. A typical interfolding apparatus includes at least two interfolding rolls, at least one knife or cutting roll, and at least one feed roll for pulling streams of web material into the interfolding apparatus. The web material is generally cut at or near the knife rolls and then travels to a bed roll, which may include a vacuum to help guide the web through its path. From the bed roll, the web travels to a lap roll to overlap the sheets, which are eventually transferred to a nip between the interfolding rolls.
In known interfolder designs where a multi-fold stack of sheets is desired (e.g., sheets that include two folds, forming three panels, where the third panel of one sheet is interfolded with the first panel of another sheet), the lap roll drives the web of sheets to a slow-down roll that travels at a speed ⅓ slower than the speed of the lap roll. The slow down roll delays the movement of a sheet to allow the next consecutive sheet to overlap the trailing ⅓ of the first sheet. Thus, in the known interfolders, the transfer and overlap of the sheets is done at an intermediate station before the overlapped sheets are transferred to the folding rolls. The addition of the slow down roll adds to the overall size, expense, and complexity of the interfolder. It is thus desirable to provide an interfolder capable of forming multi-fold stacks of sheets that is more compact, simpler to operate, and simpler to manufacture.
Some embodiments of the invention provide an interfolding apparatus and a method of interfolding sheets of web material that improves the configuration and operation of the interfolding apparatus.
In one embodiment, the invention provides an interfolding apparatus including a knife roll rotatable about an axis and operable to cut successive sheets from a stream of web material issuing from a source in a downstream direction. A folding roll is positioned downstream of the knife roll, the folding roll rotatable in a first direction at a first roll speed. An adjacent roll is disposed adjacent to the folding roll and is rotatable about an axis in a second direction at a second roll speed. The additional roll is operable to receive the successive sheets and release the successive sheets in the downstream direction toward the folding roll. The folding roll and the additional roll define a nip therebetween, the successive sheets passing through the nip. The first roll speed of the folding roll is different from the second roll speed of the additional roll, the difference in speed between the folding roll and the additional roll operable to overlap adjacent portions of the successive sheets onto the folding roll.
In another embodiment, the invention provides a method of interfolding sheets of web material. The method includes issuing web material in a downstream direction from a source, cutting with a knife roll the stream of web material into successive sheets, rotating an additional roll at a first roll speed, and transferring each sheet to the additional roll. The method further includes rotating a folding roll at a second roll speed, transferring each sheet to the folding roll, slowing the sheet with the folding roll, overlapping adjacent portions of the successive sheets onto the folding roll, and interfolding the overlapped sheets.
In another embodiment, the invention provides an interfolding apparatus comprising a knife roll rotatable about an axis and operable to cut sheets from a stream of web material issuing from a source in a downstream direction, and a folding roll positioned downstream of the knife roll and adapted to receive the sheets, the folding roll rotatable in a first direction. A lap roll is adjacent the folding roll that is rotatable about an axis in a second direction, the lap and folding roll defining a nip therebetween. The sheets are directly transferred from the lap roll to the folding roll to overlap adjacent portions of successive sheets onto the folding roll.
In another embodiment, the invention provides a method of interfolding sheets including issuing web material in a downstream direction from a source, cutting with a knife roll the stream of web material into sheets, transferring each sheet to a rotating lap roll, and transferring each sheet directly from the lap roll to a rotating folding roll. Some embodiments include overlapping a trailing edge of a first sheet with a leading edge of a second successive sheet on the folding roll, and interfolding the overlapped sheets.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
An interfolder, or interfolding apparatus 10, of one embodiment of the present invention is illustrated in
As shown in
A knife roll 54 is mounted for rotation about an axis 58. The knife roll 54 contains blades 62a, 62b that cooperate with a bed roll 66, as will be described in detail below. The knife roll 54 and bed roll 66 are adjacent each other and form a nip 70 therebetween. A pressure roll 74 is mounted adjacent the knife roll 54 for rotation about an axis 78.
In the embodiment illustrated in
The bed roll 66 is mounted for rotation about an axis 86. The bed roll includes recesses 88 in the surface thereof for cooperating with the blades 62a, 62b of the knife roll 54. The bed roll 66 also includes a vacuum source 90 and a vacuum valve 94 operable to open and close vacuum ports 98 located on either side of the recesses 88 for controlling the web W as it passes through the first nip 70. In some embodiments, the vacuum valve 94 includes adjustable slides 102 for controlling the application of the vacuum.
Referring now to
The lap roll 106 includes relief areas 118 in the surface thereof, the function of which will be described in detail below. The relief areas 118 of the illustrated embodiment are formed by a separate curved plate inset into the surface of the lap roll 106, though the relief areas 118 can be integrally formed with the lap roll 106. The lap roll 106 also includes a vacuum source 122, vacuum valves 126, and vacuum ports 130 positioned about the circumference of the lap roll 106. As with the bed roll 66, in some embodiments, the lap roll 106 vacuum valves 126 include adjustable slides 134 for controlling the application of the vacuum.
Folding rolls 138a, 138b are mounted about axes 142a, 142b (see
A tail roll 166 is mounted adjacent the folding roll 138a for rotation about an axis 170. The tail roll 166 includes tail roll tuckers 174 extending outwardly from the outer surface of the tail roll 166, and relief areas 178 for receiving a portion of a sheet 82, as will be described in detail below. The tail roll 166 and folding roll 138 define a nip 182 therebetween. While the tail roll 166 of the illustrated embodiment is a rotatable roll, in other embodiments the tail roll could be a fixed guide. In other embodiments, the fixed tail roll is preferably curved.
The operation of the interfolding apparatus 10 described above will now be described in detail. As shown in
Once the web W is slit to the desired width, the web W passes over the first pull roll 38, which travels in a counterclockwise direction about the axis 42 to draw the web W toward the second pull roll 46, as is shown in
As shown in
As the web W enters the nip 70, the vacuum valves 94 turn on the vacuum ports 98 in the bed roll 66. The vacuum applied to the web W assists in carrying the sheet 82 around the bed roll 66 to the pressure roll 74. The pressure roll 74 helps pinch the sheet 82 to the bed roll 66 to keep the sheet 82 from backing up (i.e., the pressure roll 74 keeps the web taught), and allows the web W passing through the nip 70 to be cut to the desired sheet length.
As shown in
With reference to
As shown in the illustrated embodiment, the folding roll 138a is traveling at approximately ⅔ the speed of the lap roll 106 and thus the folding roll 138a slows the speed of the sheet 82 as the sheet 82 passes through the nip 146. More specifically, the slower speed of the folding roll 138a causes the leading edge L of the sheet 82 to slow as the sheet passes through the nip 146. The vacuum of the lap roll 106 retains a trailing portion of the sheet 82 against the lap roll 106 as the sheet 82 moves through the nip 146, including a trailing edge T of the sheet 82. Thus, the trailing edge T is moving at the faster speed of the lap roll 106.
As shown in
As mentioned above, conventional interfolding devices can create overlapping sheets. However, the conventional interfolding devices that rely upon a change in speed in the rolls of the interfolder utilize a separate slowdown or transfer roll that slows the sheets for the purposes of allowing overlap between successive sheets, and then passes the sheets to the folding roll or rolls. This additional intermediate roll or transfer station adds to the overall size, complexity, and expense of the interfolder. The interfolding apparatus 10 of the present invention is more compact, less expensive, and simpler to operate by eliminating the need for a separate slowdown roll or transfer station.
Referring now to
As shown in
Various features of the invention are described in the following claims.
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Number | Date | Country | |
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20070082800 A1 | Apr 2007 | US |