Abstract:
A machine for producing an endless filter rod comprises a multi-section garniture and a multiple garniture belt drive system that includes several garniture belts having linear aligned portions for delivering filter paper with filter components thereon through the sections of the garniture. Multiple garniture belts eliminate the need for a long belt and the disadvantages associated with a long belt such as excessive stretching and side movements or wander of the belt.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a machine for producing an endless filter rod, and more particularly to filter rod combining and making machinery that includes a multi-section garniture and multiple garniture belts for delivering filter paper with filter components thereon through the garniture sections along a linear path. 
   Filter rods for making individual cigarette filters are produced by pulling paper axially down a fluted rail or garniture. As the paper is pulled through the garniture a series of folders, adhesive application systems, and heaters and/or cooling systems form the paper around the filter components and seal the paper to produce the finished filter rod. Ultimately the cigarette filter rods are cut at selected locations along their length to form individual cigarette filters, and such individual filters are attached to tobacco rods by tipping paper, as is well known in the art. Paper is pulled through the garniture by a single endless garniture belt which is driven by a rotating drum. As the paper enters the garniture, filter material such as cellulose acetate tow and/or other components such as carbon granules are deposited on the paper. 
   The garniture belt is driven by the machine in such a way that the paper speed matches the delivery of the filter material and/or other components. Various paper forming operations, insertion stations to add additional filtering materials, filter rod inspection, and the like occur during the rod forming process in the garniture. These operations result in the need to increase the length of the machine and separate the garniture into multiple sections. This increase in machine length and separation of the garniture into spaced apart sections increases the length of the garniture belt. Garniture belts are currently available in lengths up to 7 meters. However, these longer belts are difficult to run due to excessive stretch and side movement or wander of the belt. 
   SUMMARY OF THE INVENTION 
   Accordingly, one of the objects of the present invention is the provision of multiple garniture belts to avoid the use of a single excessively long belt which is difficult to operate because of excessive strength and side movements. 
   Another object of the present invention is a belt drive system that automatically controls the speed of multiple garniture belts on filter rod combining and making machinery. 
   In accordance with the present invention, a machine for producing an endless filter rod comprises a garniture and multiple garniture belts having linear aligned portions for delivering filter paper with filter components thereon through the garniture along a linear path. 
   The garniture may include upstream and downstream garniture sections in alignment and spaced apart from one another, and the multiple garniture belts may comprise an upstream belt passing through the upstream garniture section and a downstream garniture belt passing through the downstream garniture section. 
   In one embodiment of the present invention a single motor driven drum is connected to frictionally engage both the upstream and downstream garniture belts for driving the belts at substantially the same linear speed or where the downstream belt is driven at a slightly higher linear speed than the upstream belt. In another embodiment of the invention, a single motor driven drum is connected to frictionally engage one of the garniture belts for directly driving that belt. An idler drum having a diameter substantially equal to the motor driven drum is connected to frictionally engage the other garniture belt while an idler nip roller between the drums frictionally engages both the motor driven drum and the idler drum to thereby transmit rotational power to the idler drum so that the first and second garniture belts are driven at substantially the same linear speed or where the downstream belt is driven at a slightly higher linear speed than the upstream belt. 
   In still another embodiment of the invention, a first motor driven drum is connected to frictionally engage the upstream garniture belt for directly driving that belt while a second motor driven drum is connected to frictionally engage the downstream garniture belt for directly driving that belt. Other drive systems may also be used as explained in more detail below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Novel features and advantages of the present invention in addition to those mentioned above will 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 diagrammatic side elevational view of a filter making machine with a single long garniture belt, according to the prior art; 
       FIG. 2  is a diagrammatic side elevational view of a filter making machine with multiple garniture belts, according to the present invention; 
       FIG. 2A  is a sectional view taken along line  2 A— 2 A of  FIG. 2 ; 
       FIG. 2B  is a sectional view taken along line  2 B— 2 B of  FIG. 2 ; 
       FIG. 3  is a diagrammatic side elevational view of another filter making machine with multiple garniture belts, according to the present invention; 
       FIG. 4  is a diagrammatic side elevational view of still another filter making machine with multiple garniture belts, according to the present invention; 
       FIG. 5  is a diagrammatic side elevational view of another filter making machine with multiple garniture belts, according to the present invention; and 
       FIG. 6  is a diagrammatic side elevational view similar to  FIG. 5 , but additionally illustrating an arrangement for sensing tension variations of the continuous filter rod and then making incremental speed adjustments in response thereto to the phase relationship between the upstream and downstream garniture belts, according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring in more particularity to the drawings,  FIG. 1  illustrates the prior art and specifically a filter making machine  10  including a fluted rail or garniture  12  and a single long garniture belt  14 . Machine  10  includes a pretensioned filter paper supply roll  16  for delivering filter paper  18  through the garniture  12  during the filter making process. A motor driven drum  20  together with an array of idler rollers  22  drive and guide the garniture belt  14  along a path of travel that includes a linear portion through the garniture  12 . Belt  14  pulls paper  18  axially through the garniture  12 , as is well known in the art. 
   Spaced apart filter plugs such as cellulose acetate plugs  24  are delivered by conveyor  26  onto the filter paper  18 . Other filter components (not shown) may also be delivered for placement upon the filter paper. As the paper  18  passes through the garniture  12  a series of folders, adhesive application systems, heaters and/or cooling systems, etc., form the paper around the filter components such as the cellulose acetate plugs  24  and seal the paper to produce a filter rod  28 . Ultimately, the cigarette filter rod is cut at selective locations along its length to form individual cigarette filters and such filters are then attached to tobacco rods by tipping paper, as is well known in the art. 
   The present invention is best described against such background prior art, and  FIGS. 2 through 6  illustrate several exemplary embodiments of the invention wherein similar reference characters are used to identify similar parts. 
     FIG. 2  illustrates a machine  50  for producing the endless filter rod  28 . Machine  50  comprises a garniture that includes an upstream garniture section  52  and a downstream garniture section  54  in alignment and spaced apart from one another. Overall, garniture sections  52 ,  54  perform the same function as garniture  12  of FIG.  1 . 
   Machine  50  also comprises multiple garniture belts having linear aligned portions for delivering filter paper  18  with filter components  24  thereon through the garniture sections  52 ,  54 . In this regard, an upstream garniture belt  56  passes through upstream garniture section  52  while a downstream garniture belt  58  passes through downstream garniture section  54 . 
   Machine  50  includes a motor driven drum  60  connected to frictionally engage both garniture belts  56 ,  58  for driving the belts at substantially the same linear speed. Alternatively, the downstream belt  58  may be driven at a slightly higher speed than belt  56  by allowing slight slippage between drum  60  and belt  56  through modification of the friction therebetween. This speed differential places a slight tension on paper  18  as it travels through machine  50 . The drive for drum  60  may be mechanical or electrical such as a servo motor, for example. An array of idler roller  22  are arranged to define the path of travel of each garniture belt. 
     FIG. 2A  diagrammatically illustrates a portion of upstream garniture section  52  where the filter paper  18  is formed into a U-shape while sectional  FIG. 2B  shows a portion of the downstream garniture  54  where the filter paper  18  is folded around the cellulose acetate plugs  24 . 
     FIG. 3  illustrates another filter making machine  70  including upstream and downstream garniture belts  56 ,  58 , each including linear portions that travel through the upstream and downstream garniture sections  52 ,  54 . The belt drive system for machine  70  includes a motor driven drum  72  connected to frictionally engage garniture belt  58  for directly driving that belt. The drive for drum  72  may be mechanical or electrical such as a servo motor, for example. An idler drum  74  having a diameter substantially equal to that of motor driven drum  72  is connected to frictionally engage the upstream garniture belt  56  while an idler nip roller  76  frictionally engages both the motor driven drum  72  and the idler drum  74 . This arrangement transmits rotational power to the idler drum  74  so that both garniture belts  56 ,  58  are driven at substantially the same linear speed. Alternatively, the upstream garniture belt  56  may be driven at a slightly lower linear speed relative to the downstream belt  58  by allowing slightly slippage between the idler nip roller  76  and drum  72  or between nip roller  76  and idler drum  74 . Slippage may also be allowed between belt  56  and drum  74  to produce the lower speed of belt  56 . However, accomplishing the relatively slower speed of belt  56  produces tension on paper  18  as it travels through machine  70 . Frictional interaction between the idler nip roller  76  and driven drum  72  and idler drum  74  may be adjusted by increasing or decreasing the forces between these rollers with the mechanism  78  shown in FIG.  3 . 
     FIG. 4  illustrates another filter making machine  80 , according to the present invention. Machine  80  uses a motor driven drum  82  to directly drive downstream garniture belt  58  and a motor driven capstan  84  functions to drive upstream garniture belt  56 . The drive for drum  82  and capstan  84  may be mechanical or electrical such as a servo motor, for example. Capstan  84  has a smooth outer surface and runs at a surface speed slightly higher than driven drum  82 . Tension is applied to upstream garniture belt  56  in such a way that the friction between the belt and the capstan  84  is slightly less than what is needed to overcome static friction and pull the garniture belt  56  and filter paper  18  through upstream garniture section  52 . As machine  80  starts to operate, the downstream garniture belt  58  pulls the paper and assists in overcoming static friction in the upstream garniture section  52 . At this point the capstan  84  provides enough friction to allow the upstream garniture belt  56  to run at a matched speed with downstream garniture belt  58 . 
     FIG. 5  diagrammatically illustrates a filter making machine  90  that uses two separate individual motor driven drums  92 ,  94 . The drive may be mechanical or electrical, such as with a servo motor, for example. The downstream motor driven drum  92  and the downstream garniture belt  58  pull the paper  18  and the filter rod  28  at a particular speed. The upstream motor driven drum  94  and the upstream garniture belt  56  preferably run at a slightly slower speed. Such speed differential may be produced by using a slightly smaller diameter drum on drive  94  or by running the electrical drive at a slightly slower speed. Preferably the downstream garniture belt  58  is coated with a non-slip coating  96  on the paper engaging side thereof to ensure there is no slippage of the paper. The upstream garniture belt  56  is not coated which allows paper  18  and the filter components thereon to slip slightly. 
     FIG. 6  diagrammatically illustrates still another machine  100  for producing filter rods  28 . Two independent motor driven drums  102 ,  104  are utilized to drive the upstream and downstream garniture belts  56 ,  58 . The particular drive may be mechanically or electrically such as a servo motor, for example. Differences in speeds between the upstream and downstream garniture belts  56 ,  58  produce a particular tension in the filter rod  28  between the upstream and downstream garniture sections  52 ,  54 , and a sensor  106  is positioned between the garniture sections to determine the relative tension on the filter rod in that area. Sensor  106  consists of a vertically traveling member  108  loaded against the filter rod  28  by a coil spring  110 . The force of the coil spring slightly deflects the filter rod  28  a distance that is related to the tension in the rod. Such deflection represented at A is measured at B and a signal is transmitted to a processor  112  which determines the tension in filter rod  28 . If the tension varies from a predetermined value, processor  112  signals drive  104  to make incremental adjustments to the phase relationship between drive  104  and the drive  102  for the downstream garniture belt  58 . If necessary the electronic gearing ratio of drum drive  104  may be altered.