Abstract:
A method and device for cutting a pleat-folded web material into a plurality of pleat-folded towelettes. A cutting station has one or more rotary knives that rotates axially and carry a one or more blades having a non-linear, typically curved, cutting edge. The pleat-folded web passes continuously through the cutting station in a direction transverse to the axis of the rotary knife, and is severed into units of pleat-folded towelettes by the cutting edge of the rotary knife at a predetermined length.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of the present invention generally relates to packaged towelettes, and more particularly, to the cutting of pleat-folded towel material into individual towelettes. 
       BACKGROUND OF THE INVENTION 
       [0002]    An assembly line-like apparatus for the creation of individually packaged moist towelettes has been available since the 1960s. U.S. Pat. No. 3,286,435 to Weinberger et al., discloses an apparatus having a folding station, a cutting station, and a stuffing station. A similar apparatus is disclosed in U.S. Pat. No. 3,481,099 to Clancy et al. Another more recent apparatus is disclosed in U.S. Pat. No. 3,973,373 to Williams et al. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention provides a method for cutting a pleat-folded web material into a plurality of pleat-folded towelettes, comprising the steps of: 1) providing a cutting station that includes a rotary knife that rotates around an axis, the rotary knife including at least one blade having a non-linear cutting edge; 2) passing continuously a pleat-folded web through the cutting station in a direction transverse to the axis of the rotary knife; 3) rotating the rotary knife in a rotation direction of the passing through direction of the pleat-folded web, to sever the pleat-folded material with the non-linear cutting edge at a predetermined length and along a non-linear cutting line, to form a plurality of pleat-folded towelettes. 
         [0004]    The present invention also provides a rotary knife for cutting a towelette from a web of continuously longitudinally moving pleat-folded material, comprising a rotary drum and at least one non-linear blade extending from a periphery of the rotary drum, the at least one non-linear blade having a non-linear cutting edge. 
         [0005]    An aspect of the present invention is a rotary knife and a method for cutting a pleat-folded web of material with the rotary knife, that severs the end of the pleat-folded material at a predetermined length into pleat-folded units along a non-linear sever line. 
         [0006]    Another aspect of the present invention is a curved blade for a rotary knife having a non-linear, preferably curved cutting edge. 
         [0007]    A further aspect of the present invention is an insert on which one or more blades is disposed. The insert is secured into a corresponding channel in the periphery of the rotary knife. 
         [0008]    Another aspect of the present invention is a method of orienting the blade so that the end portions of the curved cutting edge lead the blade toward the pleat-folded web during the cutting. 
         [0009]    Another aspect of the present invention is a method including synchronizing the linear speed of the pleat-folded web to the tangential speed of the cutting edge of the blade of the rotary knife. 
         [0010]    From the foregoing disclosure and the following more detailed description of the various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of wet towelettes and their creation. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These and further features of the present invention will be apparent with reference to the following description and drawings wherein: 
           [0012]      FIG. 1  is a schematic drawing of an apparatus of the invention, comprising a cutting station including a rotary knife, for making and packaging units of pleat-folded towelettes. 
           [0013]      FIG. 2  is a perspective view of the cutting station with the rotary knife and curved blade of  FIG. 1 . 
           [0014]      FIG. 3  is an elevation view of the rotary knife and the knife blade of  FIG. 2  taken along line  3 - 3  of  FIG. 2 . 
           [0015]      FIG. 4  is a plan view of the rotary knife and the knife blade of  FIG. 2  taken along line  4 - 4  of  FIG. 2 . 
           [0016]      FIG. 5  is a plan view of a severed, pleat-folded towelette made using the rotary knife of  FIG. 2 . 
           [0017]      FIG. 6  is a plan view of an alternate severed, pleat-folded towelette made by an alternate knife blade. 
           [0018]      FIG. 7  and  FIG. 8  are plan views of the unfolded towelettes of  FIG. 5  and  FIG. 6 , respectively. 
           [0019]      FIG. 9  is a plan view of the severed, pleat-folded towelette of  FIG. 5 . 
           [0020]      FIG. 10  is a plan view of the folded towelette of  FIG. 9  packaged within a sealed film pouch. 
           [0021]      FIG. 11  is a plan view of the film pouch of  FIG. 10  after opening along a tear line to provide removal access to the packaged towelette. 
           [0022]      FIG. 12  is an alternative plan view of the unfolded towelette of  FIG. 7 . 
           [0023]      FIG. 13  is a top view of the pleat-folded towelette, with the bottom view being the same. 
           [0024]      FIG. 14  is a front view of the pleat-folded towelette of  FIG. 13 . 
           [0025]      FIG. 15  is a back view of the pleat-folded towelette of  FIG. 13 . 
           [0026]      FIG. 16  is a right side view of the pleat-folded towelette of  FIG. 13 . 
           [0027]      FIG. 17  is a left side view of the pleat-folded towelette of  FIG. 13 . 
       
    
    
       [0028]    The appended drawings are not necessarily to scale, and are illustrative of the basic principles of the invention. The specific design features of apparatus as disclosed herein, including, for example, specific dimensions, orientations locations, and shapes of the various components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened for clarity or illustration. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    An embodiment of the present invention is shown in  FIGS. 1-3  as a process for forming pleat-folded towelettes, where a continuous, longitudinally-moving web  6  of pleat-folded material is cut into units of predetermined length at a cutting station  20 , and which are packaged within foil pouchs  41 . A detailed description of an apparatus and method for forming, cutting and packaging a pleat folded towelette has been shown by Weinberger et al. U.S. Pat. No. 3,286,435, Williams, Sr. et al U.S. Pat. No. 3,973,373, and Clancy et al. U.S. Pat. No. 3,481,099, the disclosures of which are incorporated herein by reference in their entireties. A mill roll  1  unrolls a web of towel material  2  over an idle roller  3  and into a fan folder  4  to form a pleat-folded web  6 . The continuously-moving pleat-folded web  6  moves across a breaker roller  5  into the pinch of a pair of pull rollers  7  that pull the pleat-folded material  6  tight and push the web  6  forward to the cutting station  20 . 
         [0030]    The cutting station  20  comprises a rotary knife  21  and an anvil drum  22 . The rotary knife  21  comprises one or more blades  23  that sever the pleat-folded web  6  into individual towelettes  40  units of a desired length and the pre-determined shape. The present invention provides a non-linear blade  23  that cuts the leading end edge  43  and the trailing end edge  44  of each towelette  40  in a non-linear, including a curved, shape. The severed pleat-folded towelette  40  is then folded in half along its lateral centerline  45  and pushed into a film pouch  41  using an insertion dive arm  42 . A liquid solution, including a cleaning or other liquid composition, can sprayed into the interior of the film pouch  41  prior to or after the severed pleat-folded towelette  40  is inserted. The filled foil pouch  41  is then cleaned, and sealed to form a single-use towellette package  48  ( FIG. 10 ). 
         [0031]      FIGS. 2 and 3  show a pair of pleat-folded webs  6  moving through the cutting station  20  between a rotary knife  21  that has a pair of curved blades  23 , and an anvil drum  22 . The pair of curved blades  23  have a non-linear cutting edge  26  that crush cut the pleat folded webs  6  into individual units of a pleat-folded towelette  40  at a predetermined length against the anvil drum  22  with each rotation of the rotary knife  21 . The pair of curved blades  23  are formed as an integral part of an insert  24  that is inserted and secured into a complimentary channel  25  formed into the peripheral surface of the rotary knife  21 . The insert  24  is secured with typical securing means, such as bolts (not shown) inserted through the opposite side of the drum of the rotary knife drum that thread into the base of the insert  24 . The insert  24  can be easily removed and replaced with a different insert having differently shaped or sized blades, or the same if worn or broken, without needing to purchase an entirely new rotary knife  21 . 
         [0032]    The web material can be any woven or non-woven fibrous material including hydrophilic and/or hydrophobic fibrous or formed webs. 
         [0033]      FIG. 4  illustrates a plan view of the rotary knife, showing the blades  23  having curved cutting edges  26 , with a curved shape having a center portion and two end portions  28 . The curved cutting edge  26  can have an arc with a radius “R” in relation to the radius “r” (FIGS.  2  and  3 ) to the cutting edge  26  of the rotary knife  21  (from the axis  30 ). Each point along the edge  26  of the blade  23  is a radial distance “r” from the axis  30  to ensure a proper crush cutting as the blade  23  passes across the anvil drum  22 . In the illustrated embodiment, the ratio of the radius “R” to the radius “r” is about 1.5-1.0. It would be understood that other ratio of R″ to “r” can be used depending upon the desired curvature of the end cuts and the mechanical devices used for cutting. It would also be understood that only one blade might be used on an insert, or that two inserts or more can be installed on a rotary knife drum laterally side-by side, or circumferentially spaced along the periphery, as the need and design might require. It would also be understood that the non-linear shape of the blade can take many forms and shapes, including symmetrical and non-symmetrical shapes, curves with one or more inflection points, linear and curvilinear cutting edge portions, and combinations thereof. 
         [0034]      FIG. 2  also illustrates a method of using the rotary knife of the invention for cutting the pleat-folded web  6  into individual towelettes  40 . The pair of curved blades  23  are oriented parallel to the rotational axis  30  of the drum of the rotary knife  21 . Blade  23  can rotate in the direction of its concavity, so that the end portions  28  lead or precede the center portion of the edge toward the pleat-folded web, or alternatively in the opposite direction. As the blade  23  approaches the web  6 , the end portions  28  of the cutting edge  26  first contact the pleat-folded web  6  along its longitudinal side edges. This facilitates pulling of the pleat-folded web  6  forward evenly through the cutting station through the rotary knife  21  and anvil drum  22 . The rotary knife  21  and the anvil drum  22  are positioned parallel and spaced apart laterally to maintain a crush contact of the curved cutting edge  26  of the blade  23  onto the peripheral surface of the anvil drum  22  with each rotation, which is sufficient to sever the pleat-folded web  6  into the individual towelettes  40 . 
         [0035]    The longitudinal center of the pleat-folded web  6  is aligned with the center  27  of the curved blade  23  for proper cutting of the curved shape. The width “w” of the cutting edge  26  of the blade  23  should be greater than the width of the pleat-folded web  6 , and sufficiently greater so that the entire width of the web  6  is cut through, even if the tracking of the web  6  under the rotary knife  21  wanders a little. 
         [0036]    The method of cutting the pleat-folded web  6  can include the steps of: feeding the pleat-folded web  6  through the cutting station at a linear speed that is synchronized to the tangential speed of the cutting edges  26  of the blades  23 . Synchronizing the speeds helps to avoid stretch or slack in the web  6 , and facilitates aligned movement of the pleat-folded web  6  through the cutting station  20 . In this embodiment the pull rollers  7  have tangential speed that imparts a linear speed to the pleat-folded material that is equal to the tangential speed of the cutting edges  26 . 
         [0037]      FIG. 5  shows a piece of pleat-folded towelette  40  after being severed from the web  6  with the curved blade  23 . The severed, pleat-folded towelette  40  has a leading curved edge  43  and a trailing curved edge  44  at opposite ends that are identically oriented, resulting in one end edge being concave and the other end edge being convex. Lateral centerline  45  bisects the length of the towelette  40 , along which the towelette is folded and stuffed into the film pouch  41  via an insertion dive arm  42 . The similar orientation of the end edges of the towelette provides the folded towelette  50  with a unique appearance as shown in  FIG. 9 , and gives the edges of the unfolded towelette  70  a scalloped appearance as shown in  FIG. 7 . 
         [0038]      FIG. 6  is an example of an alternate embodiment of the invention, where a pleat-folded towelette  60  is formed using a differently-shaped non-linear blade for cutting the pleat-folded web.  FIG. 8  shows the unfolded towelette  80  from the pleat-folded towelette  60  shown in  FIG. 6 . 
         [0039]      FIG. 10  shows a folded towelette  50  packaged within the film pouch  41  having a tear notch  49  that is sealed to form a towelette pouch product  48 . Upon opening with the tear notch along the top edge of the sealed pouch, as shown in  FIG. 11 , the towelette  50  exposed the opposed concave edge  43  and convex edge  44  to the user for grasping, which allows the user to more easily pull the towelette  50  out of the opened film pouch. 
         [0040]      FIG. 12  shows an ornamental view of an unfolded towelette of the invention. The broken lines form no part of the claim.  FIGS. 13-17  show ornamental views of the pleat-folded towelette of the invention.