Patent Publication Number: US-7712698-B2

Title: Method and apparatus for forming a sheeted roll of material

Description:
TECHNICAL FIELD 
   The present invention relates to method and apparatus for forming a wound roll of material; more particularly, to method and apparatus for forming a wound roll of material comprising abutting discrete sheets of the material; and most particularly, to method and apparatus for forming such a roll wherein the sheets have an adhesive layer on at least one side thereof. 
   BACKGROUND OF THE INVENTION 
   Methods and apparatus are known for forming a roll of tape material, comprising individual sheets of material wound concentrically about a core, known in the art as a “sheeted roll”. Typically, the sheets are all of the same length, so the degree of overlap of sheets decreases as the roll diameter increases during winding of the roll, and typically, the ends of adjacent sheets are abutting. Such rolls, when wound with an adhesive surface facing outwards from the core, are useful, for example, in cleaning particles from a substrate surface by transferring the particles to the adhesive surface when the roll is rolled along the substrate surface. In such use, the roll is known in the art as a “particle transfer roller” (PTR) or a “contact cleaning roller” (CCR). As each sheet becomes loaded with particles, it is peeled off and discarded, exposing a fresh sheet for continued cleaning. 
   US Patent Application Publication No. US 2006/0057322 A1, published Mar. 16, 2006 and now abandoned, discloses a method and apparatus for forming a sheeted roll from a continuous length of such material. Continuous material having an adhesive coating is passed around a cutting roller having a traversing knife which is disposed therewithin and is selectively retractable below the surface of the cutting roller. At designated intervals, the knife is extended and traverses the continuous material, cutting therefrom a length of material defining a sheet which is then removably applied to a sheeting roller. Successive sheets, when so cut and applied to a sheeting roller, which preferably includes an inert core, define a sheeted roll in accordance with the prior art and the present invention. 
   A problem arises in applying the disclosed prior art to practice. The apparatus shown in  FIG. 4  thereof for forming the sheeted roll shows the sheeted roll  110  being distinctly off-spaced from cutting roller  312  by an unidentified gap. The specification is silent as to how the leading edge of an adhesive sheet, which is now severed from its predecessor and therefore is discontinuous, is to be transferred from the cutting roller to the sheeting roller. The present invention is directed to method and apparatus for reliably avoiding such a problem. 
   What is needed in the art is an improved means for forming a sheeted roll of material comprising overlapping sheets having adjacent abutting ends. 
   It is a principal object of the present invention to form a sheeted roll of material. 
   SUMMARY OF THE INVENTION 
   Briefly described, an apparatus in accordance with the invention for forming a wound roll of discrete overlapping sheets of web comprises optionally an unwinder for unwinding a supply roll of continuous flexible material, also referred to herein as a web, which may be adhesive on at least one side. The web is passed around a nip roller that maintains tension in the web and steers the web onto the surface of a motorized take-up core for accumulating web into a wound roll. A knife assembly including at least one transverse knife blade extended from the surface of a knife holder is driveable by a traversing mechanism across the width of the web to cut the wound web on the core into discrete sheets, the extended height of the knife blade being preferably the exact thickness of the web. In transverse cutting by the knife of the web wound on the take-up core, the knife holder travels on the outer surface of the web, thus assuring that the knife blade extends just to the outer surface of the next inner convolution of web, thereby chopping the continuous web into sheets without damaging previously wound web convolutions. If square ends are desired on the sheets, the web and take-up core are stopped momentarily prior to traverse of the knife assembly. If diagonal ends are desired on the sheets, the web and take-up core continue movement of the web during traverse of the knife assembly. In a currently preferred embodiment, the knife blade is retracted into the knife holder during the reciprocal pass of the traversing mechanism across the now-cut web. 
   In a first alternative embodiment, the knife is double-edged and not necessarily retractable into the knife holder, and the knife cuts the web into discrete sheets in alternating reciprocal transverse directions. 
   In a second alternative embodiment, a plurality of knife blades is mounted and spaced apart along an endless belt driven transversely of the web, wherein the belt defines an alternative traversing mechanism. When one blade is traversed across the web to form a first cut, the second blade is caused to return in a path apart from the web in readiness for making the next desired cut. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
       FIG. 1  is a schematic cross-sectional view of a generalized apparatus embodiment in accordance with the invention for forming a sheeted roll of material; 
       FIG. 2  is a schematic cross-sectional view of a portion of the embodiment shown in  FIG. 1 , showing a knife assembly and traversing mechanism for forming cut sheets on a tape-accumulating core; 
       FIG. 3  is a schematic longitudinal view of an alternative tape-cutting mechanism in accordance with the invention; and 
       FIG. 4  is an end view of the alternative tape-cutting mechanism shown in  FIG. 3 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 and 2 , a generalized embodiment  100  of an apparatus in accordance with the invention for forming a sheeted tape roll  102  comprises an optional unwinder  104  for unwinding a supply roll  106  of continuous flexible material  108 , also referred to herein as a web, which may be adhesive  110  on at least one side. Web  108  is led onto a cylindrical core  112  for being wound thereupon in known fashion to form a wound roll of web. In embodiment  100 , core  112  is engaged and captured by three nip rollers  116   a , 116   b , 116   c , at least one of which (preferably  116   a ) is driven in known fashion to cause web  108  to be unwound from supply roll  106  and wound onto core  112 . Nip roller  116   c  is spring loaded (not shown) to allow for diameter growth in roll  102 . In an alternative embodiment (not shown), nip rolls  116   b , 116   c  may be eliminated and core  112  is mounted on a mandrel and center-driven in known fashion. In either embodiment, nip roll  116   a  preferably serves to guide web  108  onto the winding roll  102  and to provide excellent contact of web  108  with the preceeding convolution of web. 
   A knife assembly  118  comprises a knife blade  120  disposed in a knife holder  122  that is mounted on a linear traversing mechanism  124  such as a lead screw, as is well known in the mechanical arts, for traversing the knife assembly across the width of wound web on roll  102 . The height  126  of extension of knife blade  120  is identical with the nominal thickness  128  of web  108 , and traversing mechanism  124  is arranged parallel to the axis  130  of roll  102 . Knife holder  122  is positioned on each traversing pass of knife assembly  118  such that upper surface  132  is indexed against the outer surface  134  of the last convolution  136  of web wound on roll  102 . Thus, knife blade  120  cuts just through last convolution  136 , but not into the immediately prior convolution  138 , and severs the web to produce a discrete sheet on roll  102 . Web  108  feeding onto roll  102  remains engaged therewith by virtue of nip roller  116   a.    
   To produce a square end on the severed web, the driving of the driven nip roller is stopped before the knife assembly is traversed across the web. If a diagonal end is desired, the driven nip roller is not stopped but rather may be driven at any selected speed to produce a desired diagonal angle on the sheet end. The drive is then re-energized and additional web  108  is wound onto roll  102 . When the correct length of additional web has been wound, the drive is again stopped, and the knife assembly is again traversed to produce another discrete sheet abutting the previous discrete sheet. 
   Knife blade  120  may be a single-edged knife that cuts in only one transverse direction, in which case knife blade  120  must be retracted from the path of web  108  on the return pass in preparing for the next cut. This may be done by retracting the traversing mechanism  124  radially from axis  130 , or preferably by retracting knife blade  120  in slot  140 . 
   Alternatively, knife blade  120  may be a double-edged knife (not shown) capable of cutting in both transverse directions, in which case the blade need not be retracted and sequential sheets are produced by alternate edges of the knife in alternating (reciprocal) transverse directions. 
   Alternatively, and referring now to  FIGS. 3 and 4 , a plurality of knife blades  120  and optionally knife holders  122  may be mounted and spaced apart along an endless belt  142  driven transversely of the web, wherein the belt defines an alternative traversing mechanism. For example, two blades  120   a , 120   b  may be mounted 180° apart on belt  142  such that when one blade is traversed across the web to form a first cut, the second blade is caused to return in a path apart from the web in readiness for making the next desired cut. Each knife may be mounted in a separate knife holder  122   a , 122   b  mounted on the belt as desired, or the knives may be mounted directly in the belt and the belt itself may define a knife holder. To make a square ended cut, the belt and the web are advanced alternately such that the web is stopped while the belt is moving, and the belt is stopped while the web is moving. 
   While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.