Abstract:
Method and apparatus for forming filter tubes comprises delivering a filter element to a flute on a first drum having vacuum for securing the filter element thereto. First and second tube forming rollers axially engage opposite ends of the filter element. A second drum accepts and cuts a continuous paper web with a glue pattern thereon into paper pieces, and a cut paper piece is delivered to the filter element. The paper piece is then rolled around the filter element and the tube forming rollers to form a cylindrical shape. The tube forming rollers are axially disengaged to thereby produce a filter tube with hollow ends and a control positioned filter element.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a device for rolling tubes of cigarette plug wrap with single or multiple internal filter elements. 
   SUMMARY OF THE INVENTION 
   Cigarette filter rods can be processed in pairs in the so-called “two-up” filter rod configuration. According to this configuration, one solid filter plug is placed in the middle of a tube created using plug wrap so that an empty space is created on either end of the filter plug. The empty space may then be filled with a sequence of granular material, such as carbon and the like, and solid material, such as cellulose acetate fibers or fibers with flavorant. Upon completion, a tobacco rod may be joined to each end of the filter tube using tipping paper, and the central solid filter may then be cut in half to form two cigarettes. 
   The plug wrap can wrinkle or become folded as it is rolled around the filter material. Thus, there is a need for an apparatus and method for rolling plug wrap around a filter plug that avoids the disadvantages of the prior art. Thus, the present invention relates to a device and method for rolling wrinkle-free and crease-free hollow tubes of plug wrap with single or multiple internal filter elements. 
   In accordance with the present invention, a method of forming filter tubes comprises delivering a filter element to a flute on a first drum having a vacuum for securing the filter element thereto, and axially engaging opposite ends of the filter element with first and second tube forming rollers. A continuous web of paper with a glue pattern thereon is delivered to a second drum. The paper is cut into discrete pieces, and at least a portion of the paper piece is delivered to at least a portion of the filter element in the flute of the first drum. The paper piece is rolled around the filter element and the tube forming rollers to form a cylindrical shape. The tube forming rollers are then disengaged to thereby produce a filter tube with hollow ends and a centrally positioned filter element. 
   The apparatus of the present invention comprises a flute on a first drum for accepting a filter element, the flute having vacuum for securing the filter element thereto. First and second tube forming rollers axially engage opposite ends of the filter element. A second drum accepts and cuts a continuous web of paper with a glue pattern thereon into paper pieces and delivers a cut paper piece to the filter element. A belt contacts the paper piece to roll the paper piece around the filter element. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Novel features and advantages of the present invention in addition to those noted above will be become apparent to persons of ordinary skill in the art from a reading of the following detailed description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which: 
       FIG. 1  is a side elevational view showing a tube rolling device; 
       FIG. 2  is a perspective view of a finished rolled tube with a filter in a central position; 
       FIG. 3  is a fragmental side elevational view showing the cut paper tube strip entering the right and left cowl between the rolling belt and idler tube forming roller; 
       FIG. 4  is a fragmental side elevational view with the tube forming roller removed and showing the formed tube filter being transferred from the tube forming drum to the tube removal drum; 
       FIG. 5  is a perspective view of a modified idler tube forming roller showing vacuum ports and filter holding pins; 
       FIG. 6  is a schematic side elevational view showing a tube strip being wrapped around a filter and two suction idler tube forming rollers; and 
       FIG. 7  is a schematic side elevational view showing a finished filter tube with a centrally positioned filter and with the idler tube forming rollers removed. 
   

   DETAILED DESCRIPTION 
   Embodiments of the present invention will now be described with reference to the drawings. 
     FIG. 1  is a side elevational view that schematically shows a cigarette filter tube rolling apparatus  8  according to an embodiment of the present invention. The apparatus may include a feed drum  12 , tube rolling drum  14 , tipping drum  20 , rolling belt  38 , pressure belt  40 , and take-off drum  48 . Generally speaking, a filter element  10  may travel from the feed wheel  12 , to tube rolling drum  14  where paper patches  22  may be applied and rolled around the filter element  10 . Paper  22  may be supplied from tipping drum  20 , and may have glue along its centerline of travel in order to secure plug wrap paper  22  to filter element  10 . Rolling belt  38  may drive the paper circumferentially around the filter element until glue applied at the trailing edge of the plug wrap paper engages with another surface of the paper wrapped around the filter element  10  to form a filter tube  36 . Filter tube  36  may then be placed on and removed from take-off wheel  48  in a conventional manner for further processing. The novel process and apparatus for rolling paper around the filter elements will now be described in greater detail. For purposes of illustration, certain positions during the rolling process will be designated with letters representing a particular point during the process. 
   Filter element  10  may be any conventional element of a smoking article filter, such as a plug of cellulose acetate tow or other suitable material. Filter element  10  may be provided in any conventional manner to a filter feed drum  12  comprising at least one flute  13  for accepting filter elements. For example, filter element  10  may be manually placed in flute  13  or may be delivered to the flute from a filter element creation and/or distribution apparatus. Flute  13  may be a generally semi-circular tubular shaped opening along the perimeter of the drum  12 . Flute  13  may comprise a vacuum or other suitable means conventional in the art to hold filter element  10  as the feed drum rotates in a clockwise direction as illustrated with the arrow  15  in  FIG. 1 . 
   As filter elements  10  arrive at position A, they may be transferred to a flute  16  on tube rolling drum  14  that may rotate in a counter-clockwise direction as illustrated by arrow  17 . Flute  16  may be a generally semi-circular tubular shaped opening along the perimeter of the drum  14 . The filter elements  10  may be held in the drum flutes  16  by a vacuum or other suitable means conventional in the art. 
   Each flute  16  in the tube rolling drum  14  may equipped with rollers  24 , which are designated by hidden lines shown in  FIG. 4 . Rollers  24  may be generally cylindrically shaped and may be free-spinning or may have a driving means to spin filter element  10 . Rollers  24  may be provided in pairs to allow filter element  10  and paper  22  to rotate freely during the rolling process. 
   Each flute  16  may also be equipped with tube forming rollers  30  and  32 , shown in  FIGS. 5-7 . Tube forming rollers  30  and  32  may be generally cylindrically shaped and provided to hold the filter element  10  in place during the rolling operation and/or to prevent paper  22  from wrinkling or folding during the rolling process. Tube forming rollers  30  and  32  may be moved axially along the flute on each side of filter element  10  to enclose the filter element along its axis X and may rotate with filter element  10  on rollers  24  during rolling. This axial motion is well known as described in U.S. patent application Ser. No. 11/443,659, which is hereby incorporated by reference for all useful purposes. The movement and position of the tube forming rollers may be controlled by cams, which are not shown, but are well known to those skilled in the art, as disclosed, for example, in U.S. Pat. No. 3,985,144, which is hereby incorporated by reference for all useful purposes. 
   In Position A, indicated in  FIG. 1 , tube forming rollers  30  and  32  (not shown in  FIG. 1 ) are separated by a distance sufficient to allow filter element  10  to be generally positioned within flute  16 . As the tube rolling drum  14  rotates to position B, tube forming rollers  30  and  32  may be directed axially inwardly toward filter element  10  to secure it in a predetermined position, for example, in the center of flute  16 . 
   Each flute  16  may also be equipped with cowls  26  and  28 , shown in  FIGS. 1 ,  3  and  4 . The movement and position of these cowls may be controlled by cams, which are not shown, but are well known to those skilled in the art. Cowls  26  and  28  may be moved in a grasping or scissor motion to close around the filter element  10  and idler tube forming rollers  30  and  32 . 
   Filter elements  10  can be brought in proximity with tipping drum  20  to be paired with paper segments  22 . To deliver a cut segment  22  of paper to the filter element  10 , a continuous web of paper  18  may be delivered to the tipping drum  20  where it can be cut into individual cut paper segments  22 . Paper segments  22  may have a glue pattern that is pre-applied when the paper is still continuous or the glue may be applied after the step of cutting. Continuous paper  18  may be cut using a blade  19 , cutting wheel, or other suitable cutting device conventional in the art. The paper feed and cutting process may be the same as employed in conventional cigarette filter tipping machinery. 
   At position B, a leading edge of paper segment  22  (hereafter simply “paper”) is stuck to filter element  10  by virtue of the patterned glue. Paper  22  is left to extend generally tangentially to filter element  10 . As tube rolling drum  14  rotates from position B to position C, cowls  26  and  28  pivot inwardly toward the filter element  10  and tube forming rollers  30  and  32 . This pivoting does not appreciably interfere with the paper, which at this point in the process may still extend tangentially away from filter element  10 . 
   The process of rolling paper  22  around element  10  may be commenced at position C.  FIG. 3  shows an enlarged view of filter element  10  at position C and shows the positioning of the cowls  26  and  28  relative to the filter element  10  at position C of the process. When the cowls are closed inwardly, a slight gap  34  may remain between cowl  26  and filter element  10  and, therefore, tube forming rollers  30  and  32 . A similar gap may exist between cowl  28  and filter element  10 . Gap  34  serves as a guide path for the paper  22  during the rolling process. The guide path assists in preventing the paper from wrinkling and folding back during rolling. As also shown in  FIG. 3 , cowl  28  may be separated from contact with belt  38  to allow paper  22  to be advanced without being pinched between cowl  28  and belt  38 . 
   At position C, one or more rolling belts  38  come into contact with paper  22  and the vacuum is disengaged at least slightly. A belt may be provided to contact paper  22  in the regions of tube forming rollers  30  and  32 . The rolling belt  38  may be driven by a motor  39  and guided by wheels  46 ,  47  and  49  to run at a higher speed than the surface speed of paper  22 , which is controlled by the rotational speed of rolling drum  14 . Tension in belt  38  may be maintained using tensioners  50 , which are attached to an arm  52  that pivots about a fixed point  54 . Tensioners  50  may comprise, for example, springs  55  which may be tightened or loosened using tension screws  56 , as is well known in the art for adjusting tension in a tensioning system. Thus, as the tube rolling drum  14  rotates from position C to position D, the rolling belts  38 , which have a surface speed that is faster than the rotational speed of rolling drum  14 , push paper  22  through gap  34  and around filter element  10  and tube forming rollers  30  and  32  in the flute  16 , as shown in  FIG. 6 . Thus, as shown with general reference to  FIGS. 6 and 7 , paper  22  is rolled around filter element  10  and tube forming rollers  30  and  32  until a trailing edge of glue  60  on the paper seals the seam by contacting with a portion of the paper that has been rolled around filter element  10  and tube forming rollers  30  and  32 . 
   When the filter tube  36  reaches position E, a pressure belt  40  comes into contact with the filter tube  36 . Belt  40  may be positioned between two belts  38  all of which may rotate on independent wheels  47  to allow belts  38  to contact paper  22  around tube forming rollers  30  and  32  and to allow belt  40  to contact paper  22  around filter element  10 . Additionally, wheels  47  may spin freely of each other so that one of the wheels  47  may allow belts  38  to move faster than the rotational speed of drum  14 , while another of the wheels  47  may rotate at a matched speed relative to drum  14 . Although  FIG. 1  shows only one of the wheels  47 , it should be understood that other independently rotating wheels  47  may be axially aligned with the wheel  47  shown as is known in the art of tension belt systems. 
   Belt  40  may run at a matched speed with the tube  36  and drum  14  so that belt  40  may hold tube  36  tight against the surface of flute  16 . The pressure of belt  40  may assist in maintaining tube  36  in position as the tube forming rollers  30  and  32  are removed. The vacuum may also be reengaged at this point to maintain tube  36  in position. 
   The pressure belt  40  may be tensioned using tensioners  50  as described above with reference to rolling belt  38 . As tube rolling drum  14  rotates from position E to position F, tube forming rollers  30  and  32  are axially withdrawn. This action can be observed by comparing  FIG. 6  with  FIG. 7 . 
   As the tube rolling drum  14  rotates from Position F to Position G, the left and right cowls  26  and  28  open up. The finished rolled filter tube  36  is then removed at position G, as shown in  FIG. 4 . The vacuum may again be disengaged to allow transfer to drum  48 . An exemplary finished filter tube  36  is shown in  FIG. 2 . 
   Alternatively or additionally, tube forming rollers  30  and  32  may be provided with vacuum holes  44  and/or filter engaging pins  46  as shown in  FIG. 5 . Vacuum could be applied through the vacuum holes  44  to pull paper  22  down tightly against the surface of the tube forming rollers  30  and  32  to further ensure that paper  22  follows the guide path during the rolling operation. Optional pins  46  could penetrate into the end surfaces of filter element  10  to ensure that the filter element  10  and tube forming rollers  30  and  32  roll together. 
   It should be understood that the above detailed description while indicating preferred embodiments of the invention are given by way of illustration only since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description.