1. Field of the Invention
The present invention relates to a device for folding and stacking folded sheet articles.
2. Description of the Related Art
A known apparatus for folding and stacking ⅛ fold sheet articles such as napkins is illustrated schematically in
The use of vacuum folding techniques for folding sheet articles is disclosed, for example, in U.S. Pat. Nos. 1,974,149 and 3,689,061, the entire contents of which are incorporated herein by reference.
As shown at the bottom of
It is an object of the present invention to provide a method and apparatus for folding and stacking sheet articles which produces a more uniform stack thickness.
The object of the present invention is met by a method and apparatus for folding sheet articles using two different folding devices. A stack of sheet articles is formed by interleaving the sheet articles from the two-different folding devices. The sheet article may be made from any substantially planar and foldable sheet material such as, for example, paper, plastic, or metal. According to an embodiment of the present invention, the apparatus for folding sheet articles includes two folding devices which output sheet articles having folds on opposite sides of the folded article. The folded sheet articles from the two folding devices are interleaved so that the stack includes the two opposing folds. By alternating the folded sheet articles from the two folding devices in the stack, the sheet material is evenly distributed on the opposing sides of the stack associated with the two folds, thereby producing a stack of uniform thickness.
A uniformly thick stack is easier to handle, helps reduce jam-ups in banders and case packers, and facilitates an even distribution of weight when the stacks are placed in boxes for shipping. The present invention also reduces waste because the ease of handling the product reduces downtime of the folding device, thereby increasing the rate of production and reducing the cost of production.
In a more specific embodiment, the present invention is directed to a device for folding ⅛ fold napkins with a first folding device, i.e., a plow, for making a first fold along a longitudinal length of the napkin, a quarter folder for quarter folding the napkin, and a ⅛ folder for ⅛ folding the napkin. According to the invention, two plow folders are used for receiving two separate webs of napkin material. The plow folders fold each web along a longitudinal length of the web. A separate quarter fold roll may be associated with each plow and a shared cross drive ⅛ fold cylinder may be used in the final ⅛ fold step for each napkin. Alternatively, separate ⅛ fold cylinders may be used with each feeding the ⅛ folded napkin to a belt guided accumulator table.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
In the drawings, wherein like reference characters denote similar elements throughout the several views:
A sheet article folder and stacker according to the present invention is shown in
The ⅛ folded sheet articles from the first and second webs are then moved to a stack 122 so that sheet articles from the first and second webs are interleaved. The orientation of the first and second folding devices 112a, 112b is such that the folds 113a created by the first folding device 112a on the first web 110a are arranged on an opposing side of the stack 122 from the folds 113b created by the second folding device 112b on the second web 110b as shown in FIG. 8. Furthermore, the feeding of the sheet articles from the first and second webs to the stack is synchronized, and/or the quarter fold rolls 118a, 118b are positioned, so that the ⅛ folded sheets articles are alternately placed on the stack. The alternating folds 113a, 113b in the stack 122 create an even distribution of sheet material in the stack 122, thereby making the stack more stable than if the folds 113a and 113b were all arranged on the same side.
As seen from
Although the preferred embodiment shows that the sheet article is first folded lengthwise, then in a quarter fold, and then in an eighth fold, the present invention requires only that the sheet article be folded once and that this fold be alternately arranged on opposing sides of a stack. According to the present invention, two separate trains of sheet articles are folded in folders and alternately placed on a stack of sheet articles so that the fold in articles from the first train is on an opposing side of the stack from the fold in articles from the second train. That is, the interleaved articles include folds on opposing sides of the stack.
Moreover, the anvil and knife rolls 114a, 116a, 114b, and 116b may be omitted if the sheet articles are fed in pre-cut condition to the first folding device 112a, 112b. If cutting of the web is not required, a vacuum roll may be used in place of the anvil and knife rolls.
Instead of transport device 124, many other types of transport devices may be used which move the folded sheet articles to the stack while maintaining the interleaved order of the sheet articles.
Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
Priority is claimed on U.S. Provisional Patent Application Ser. No. 60/409,691, filed on Sep. 10, 2002.
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Number | Date | Country | |
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20040048727 A1 | Mar 2004 | US |
Number | Date | Country | |
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60409691 | Sep 2002 | US |