Abstract:
An apparatus for selectively dispensing a web from a plurality of rolls of serrated bags or layflat tubing comprises a web selector for selecting and advancing a web from the plurality of rolls; a bag driver for advancing the selected web and separating a bag from the web; and a bag transfer device for transporting the separated bag from the bag driver to a location for processing. A sealer/cutter is used to produce a bag from the layflat tubing. A method of selectively dispensing a web from a plurality of rolls of serrated bags or layflat tubing comprises selecting and advancing a web from the plurality of rolls of serrated bags; advancing the selected web and separating a bag from the web; and transporting the separated bag to a location for further processing. In the case of layflat tubing, the selected web is sealed and cut to make a bag.

Description:
FIELD OF THE INVENTION 
   The present invention relates to an apparatus and method for selectively dispensing a web from a plurality of rolls of serrated bags or lay-flat tubing. 
   BACKGROUND OF THE INVENTION 
   Many packaging applications, especially food packaging, require or benefit from the use of bags made from various thermoplastic materials and structures. 
   These bags are commonly used in large scale meat processing and/or packaging systems where production speed and efficiency are important. Bags to be used in these systems are often themselves packed in boxes, the individual bags taped together so that they will feed in a predictable and efficient manner to an article loading station. Typical of such technology is U.S. Pat. No. 3,161,347 (Hannon), disclosing a tape to which bags are attached, and U.S. Pat. No. 3,587,843 (Wing), disclosing two tapes to which are attached imbricated (i.e. shingled) bags. 
   At the loading station of a conventional system, each bag is opened and then loaded with an article such as a fresh red meat subprimal or smoked and processed meat, poultry, cheese, or other perishable food product, or other product. 
   Alternatively, bags can be provided in a roll, with adjoining bags connected by a transverse line of serrations or perforations. 
   In some packaging environments, such as the packaging of various cuts of fresh red meat, individual meat cuts can vary significantly in size. If pre-made bags are used to package these individual cuts, it may be necessary to have on hand bags of different dimensions, e.g. width and/or length, to accommodate the variability in product size. 
   It is desirable to provide an apparatus and method for selectively dispensing a web from a plurality of rolls of serrated bags or lay-flat tubing. 
   SUMMARY OF THE INVENTION 
   In a first aspect, an apparatus for selectively dispensing a web from a plurality of rolls of serrated bags, each roll of bags having a series of bags connected by transverse perforations, comprises a web selector adapted to select and advance a web from the plurality of rolls of webs; a bag driver adapted to advance the selected web and separate a bag from the web; and a bag transfer device adapted to transport the separated bag from the bag driver to a location for further processing. 
   In a second aspect, a method of selectively dispensing a web from a plurality of rolls of serrated bags, each roll of bags having a series of bags connected by transverse perforations, comprises selecting and advancing a web from the plurality of rolls of serrated bags; advancing the selected web and separating a bag from the web; and transporting the separated bag to a location for further processing. 
   In a third aspect, an apparatus for selectively dispensing a web from a plurality of rolls of layflat tubing comprises a web selector adapted to select and advance a web from the plurality of rolls of layflat tubing; a sealer/cutter for producing a bag from the layflat tubing; a bag driver adapted to advance the selected web and separate the bag from the web; and a bag transfer device adapted to transport the separated bag from the bag driver to a location for further processing. 
   In a fourth aspect, a method of selectively dispensing a web from a plurality of rolls of layflat tubing comprises selecting and advancing a web from the plurality of rolls of layflat tubing; sealing and cutting the selected web to make a bag; advancing the selected web and separating the bag from the web; and transporting the separated bag to a location for further processing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings presented by way of illustration of the invention: 
       FIG. 1  is a perspective view of an apparatus in accordance with the invention; 
       FIG. 2  is a front view of the apparatus of  FIG. 1 ; 
       FIG. 3  is an enlarged view of a web selection device of the apparatus of  FIG. 2 ; 
       FIG. 4  is an enlarged view of a web driver of the apparatus of  FIG. 2 ; 
       FIG. 5  is an enlarged view of a web transfer device of the apparatus of  FIG. 2 ; 
       FIG. 6  is a front view of the apparatus of  FIG. 2  showing operation of the web transfer device of the apparatus; 
       FIG. 7  is a perspective exploded view of a part of the web transfer device of the apparatus of  FIG. 2 ; 
       FIG. 8  is a perspective view of a device for registering roll serrated bags, for use in connection with the present invention; 
       FIG. 9  is a front view of the device of  FIG. 8 ; 
       FIG. 10  is a perspective view of an alternative device for registering roll serrated bags in accordance with the present invention; 
       FIG. 11  is a perspective enlarged view of the encircled portion of  FIG. 10 ; 
       FIG. 12  is a front view of the device of  FIG. 10 ; 
       FIG. 13  is a plan view of the device of  FIG. 10 ; 
       FIG. 14  is a perspective view of another alternative device for registering roll serrated bags in accordance with the present invention; 
       FIG. 15  is a perspective enlarged view of the encircled portion of  FIG. 14 ; 
       FIG. 16  is a front view of the device of  FIG. 14 ; 
       FIG. 17  is a plan view of the device of  FIG. 14 ; and 
       FIG. 18  is a side view of the device of  FIG. 14  after a tab has reached the proximity switch of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The invention provides an apparatus, method, and system for selectively dispensing and optionally printing a discrete web from multiple sources, and optionally positioning the web at a common location. At this common location, the web can be dispensed to a container, or further processed, e.g. by utilizing a web transfer device to transfer the web to e.g. bag loading equipment. 
   “Web” herein refers to a leading portion of a roll of serrated bags, a roll of lay flat tubular film, etc. in which the leading portion is advanced to interface with the apparatus of the invention and undergo one or more of the operations disclosed herein. Serrated bags as well as lay flat tubular film are well known in the art. Serrated bags are typically in roll form, with adjacent bags attached by means of a set of perforations running transversely to the bags. These serrations allow each leading bag to be separated from the roll of bags as needed. Serrated bags each include a transverse seal at one end of the bag. 
   Although the embodiments disclosed herein are directed primarily with respect to serrated bags, those skilled in the art will understand that lay flat tubing can be beneficially used in connection with the present invention. 
     FIGS. 1 and 2  disclose an apparatus  10  for selectively dispensing a web from a plurality of rolls of serrated bags, each roll of bags having a series of bags connected by transverse perforations. The apparatus  10  includes a web selector  12 , a web printer  14 , a web driver  16 , and a web transfer device  18 . 
   In one embodiment of the invention, up to four webs of serrated bags [web  22 , web  24 , web  26  and web  28 ], each web in the form of a roll of bags, are positioned in the web selector  12 , with the free end of each web passing through a respective set of open nips. The open end of the lead bag of each web is at the free end of each respective web. In operation, the nip corresponding to the selected web is closed, and the nip is driven, thus feeding the web through the web printing device  14  (if the web is to be printed) with the free end of the web sequentially captured and driven by the nip of the web driver  16  and (if e.g. the web is to be advanced to a bag loader) positioned for engagement by the web transfer device  18 . 
   Following engagement by the web transfer device  18 , the web  22  and web transfer device  18  advance until the serration is positioned at the previous position of the free end of the web. At this time, the nip of the web selector  12  stops, separating the web at the serration because of the tension applied by the continued feeding of the web driver  16 . Following separation, the nip of web transfer device  18  continues to run until the bag tail (the upstream or trailing end of the bag) is cleared. During web advancement, the web driver  16  advances the web  22  at a slightly greater rate than the web transfer device  18  to insure that the web  22  is not pulled free of the web transfer device  18 . In embodiments where the web  22  is to be printed, the web is passed through web printer  14 , and the web is printed with indicia such as a trademark (word and/or logo), information related to the ultimate contents of the bag to be formed from web  22 , etc. Web printer  14  can be of any suitable type, such as e.g. a thermal transfer printer. Alternatively, by employing an intermittent printer (i.e. a printer that is operated in an intermittent or discontinuous manner) the print may be applied during the dwell following presentation of the web to and engagement of the web with the web transfer device  18 . The web transfer device  18  opens the bag mouth while traveling to the handoff position as shown in  FIG. 6 . 
     FIG. 3  illustrates the web selector  12  in more detail. Stationary drive rolls  32  and  34  are attached to side plate  36 . Drive rolls  32  and  34  are driven through a common reversible drive  38 . The center moveable roll assembly  40  can pivot about pivot shaft  42 , which resides in one of three positions determined by the three-position pneumatic actuator  44  acting through link  46 . 
   The three positions of the center moveable roll assembly  40  result in three possible settings, namely:
         1. web  24  nipped to drive roll  32 . This setting is achieved by actuation of pneumatic actuator  44  to cause link  12  to rotate in a counterclockwise direction. This in turn causes pivot shaft  42  to rotate in a counterclockwise direction such that center moveable roll assembly  40  pivots to the left (as viewed in  FIG. 3 ), pinching web  24  between center moveable roll assembly  40  and stationary drive roll  32 .   2. web  26  nipped to drive roll  34 . This setting is achieved by actuation of pneumatic actuator  44  to cause link  12  to rotate in a clockwise direction. This in turn causes pivot shaft  42  to rotate in a clockwise direction such that center moveable roll assembly  40  pivots to the right (as viewed in  FIG. 3 ), pinching web  26  between center moveable roll assembly  40  and stationary drive roll  34 .   3. neither web  24  or  26  nipped, with the center moveable roll assembly  40  positioned in the neutral position shown, i.e. disengaged from drive rolls  32  and  34 .       

   Thus, in one embodiment, the web selector  12  includes a first and second stationary drive roll spaced apart from one another; a central moveable roll disposed between and spaced apart from the first and second stationary drive rolls; and a mechanism for selectively moving the center moveable roll toward the first and second stationary drive rolls respectively; the center moveable roll and the first stationary drive roll adapted to accommodate a first web disposed between the center moveable roll and the first stationary drive roll, and to selectively nip the first web between the center moveable roll and the first stationary drive roll; and the center moveable roll and the second stationary drive roll adapted to accommodate a second web disposed between the center moveable roll and the second stationary drive roll, and to selectively nip the web between the center moveable roll and the second stationary drive roll. In this embodiment, two webs can be employed. These webs can be identical, but beneficially are different in some way. The difference can be a dimensional difference, such as width, length, or both; a compositional difference, such as the composition, thickness, or construction of each web; or any other difference that could be of benefit to a processor or packager. 
   In another embodiment, outer moveable roll assemblies  48  and  50  can pivot around pivot shafts  52  and  54  respectively. The moveable roll assemblies  48  and  50  are coupled by connecting link  56 , and actuated with the three-position pneumatic actuator  58  acting through link  60 , producing three conditions, namely:
         1. web  22  nipped to drive roll  32 . This setting is achieved by actuation of pneumatic actuator  58  to cause link  60  to rotate in a clockwise direction. This in turn causes moveable roll assembly  48  to rotate in a clockwise direction such that moveable roll assembly  48  pivots to the right (as viewed in  FIG. 3 ), pinching web  22  between moveable roll assembly  48  and stationary drive roll  32 .   2. web  28  nipped to drive roll  34 . This setting is achieved by actuation of pneumatic actuator  58  to cause link  60  to rotate in a counterclockwise direction. This in turn causes moveable roll assembly  50  (by means of its connection, via connecting link  56 , with moveable roll assembly  48 ) to rotate in a counterclockwise direction such that moveable roll assembly  50  pivots to the left (as viewed in  FIG. 3 ), pinching web  28  between moveable roll assembly  50  and stationary drive roll  34 .   3. neither web  22  or  28  nipped, with the outer moveable roll assemblies  48  and  50  positioned in the neutral position shown, i.e. disengaged from drive rolls  32  and  34 .       

   Thus, in this embodiment, four webs can be accommodated in a web selector. 
   In an alternative embodiment, an apparatus like those just described can be provided, in which a center stationary drive roll is positioned between, and spaced apart from, a first and second moveable roll assembly. A web can be accommodated in the space between the single stationary drive roll, and the first moveable roll assembly, and between the single stationary drive roll, and the second moveable roll assembly. The first and second moveable roll assemblies can be coupled by a connecting link, and actuated with a three-position pneumatic actuator acting through a link, producing three conditions like those described above. Alternatively, each of the first and second moveable roll assemblies can be separately actuated with its own three-position pneumatic actuator, without the need for a connecting link that couples the first and second moveable roll assemblies. 
   Thus, in this embodiment, two webs can be accommodated in a web selector. 
   To advance a specified web the required nip is closed and drive motor  38  is activated in the proper direction. Positions of the moveable roll assemblies are controlled in a manner to ensure only one web is nipped at any given time. 
   Referring to  FIG. 4  the web printing device  14  includes a printer  62 , and an anvil roll assembly including an anvil roll frame  64  that pivots around drive roll  66 . Actuator  68  opens the anvil roll  70  providing clearance for the free end of the web. After the free end of the web passes, the anvil roll  70  closes, positioning the web  22  for printing. The anvil roll assembly guides the web  22  from the web selector  12  to the web printing device  14 . The web driver  16  includes drive rolls  66  and  72  driven by a drive motor [not shown]. Guiding the web  22  from the web selector  12  to the web printing device  14  are belts  74  with idler roll  76  and belts  78  with idler roll  80 . During operation, the web driver  16  can present e.g. between 2 and 3 inches of a web segment  82  to the web transfer device  18  as shown in  FIG. 6 . 
   As shown in  FIG. 5 , the web transfer device  18  includes a web transfer frame  84  that pivots around pivot shaft  86 , a stationary vacuum bar  88  (i.e. stationary relative to the web transfer frame  84 ), positioned opposite a movable vacuum bar  90 . The movable vacuum bar  90  is connected to the web transfer frame  84  with link  92  and actuator  94  that maintain its orientation to the stationary vacuum bar  88 . The gap between vacuum bars  88  and  90  is controlled by link  96  and actuator  94 . The actuator  94  is used to open or close the vacuum bars  88  and  90  at the web drive device  16  as required. As the bag transfer frame  84  rotates, attachment of link  96  to side plate  9  at pivot point  87  results in an additional opening motion of the vacuum bar  90  independent of the action of actuator  94 . The bag opening sequence is shown in  FIG. 6 . 
   The exploded view of movable vacuum bar  90  in  FIG. 7  shows that the outer vacuum cups  98  and inner vacuum cups  100  are in one embodiment connected to separate independently controlled vacuum channels  102  and  104 . A common channel can alternatively be utilized, but the potential exists for the outer vacuum cups  98  to not be covered for narrow web widths, thus decreasing the vacuum and reducing the holding efficiency of the remaining covered vacuum cups. 
   In the operation of the present invention, in embodiments where rolls of serrated bags are employed, it is beneficial to provide a way of dispensing each bag an appropriate distance as it feeds from the selected roll. 
   One way of accomplishing this is the use of printed registration marks. The use of printed registration marks is generally well known in the web handling and packaging arts. 
   One disadvantage of using printed registration marks is that an additional operation is required in manufacturing the roll of serrated bags. The printed registration marks must be printed in sequential fashion on each of the series of bags. This adds cost to the roll of bags. 
   In another embodiment, and referring to  FIGS. 8 and 9 , each bag  106  in a roll of serrated bags includes a seal  108 , which can be rectilinear or curved, and a serration  110  adjacent seal  108 . Seal  108  is a different thickness than the unsealed film around it. As shown in the drawings, the machine direction, i.e. the path of travel of the bags, is such that the seal  108  precedes the serration  110 ; that is, the seal is positioned downstream of the serration. Alternatively, the serration  110  can precede the seal  108 . Bag registration for further machine processes, such as printing, and/or separation of a bag from the next sequential bag in the series of bags, can be accomplished by sensing the rotary displacement of lever arm  112  around pivot point  114  due to the action of seal  108  displacing roller  116  away from fixed member  118 . Sensing the motion of lever arm  112  is done by proximity switch  120 , or other suitable motion detection device. A registration signal is thus generated as each seal passes a fixed point. 
   In another embodiment, and referring to  FIGS. 10 to 13 , each bag  122  in a roll of serrated bags includes a seal  124 , which can be straight or curved, and a serration  126  adjacent seal  124 . As shown in the drawings, the machine direction, i.e. the path of travel of the bags, is such that the seal  124  precedes the serration  126 ; that is, the seal is positioned downstream of the serration. Alternatively, the serration  126  can precede the seal  124 . 
   As shown in  FIG. 11 , serration  126  is constructed with alternated holes and bridges with dimensions of e.g. 0.25 inches for A and 1.0 inches for B. Any suitable dimensions and distribution of holes and bridges can be employed. Bag registration for further machine processes, such as printing, and/or separation of a bag from the next sequential bag in the series of bags, can be accomplished by sensing the drop in air pressure in air line  128  by means of sensing port  130  as the elongated hole portion of serration  126  passes over the exit end  132  of air line  128 . A registration signal is thus generated as the serration  126  of each sequential bag passes a fixed point. 
   The embodiment of  FIGS. 10 to 13  can be beneficially used with a variety of bag types, including patch bags, and bags without patches. An additional advantage of this embodiment is that the elongated hole portion of the serration  126  provides an opening for the release of trapped air during winding in the manufacturing process. 
   In yet another embodiment, and referring to  FIGS. 14 to 18 , each bag  134  in a roll of serrated bags includes a seal  136 , which can be straight or curved, and a serration  138  adjacent seal  136 . As shown in the drawings, the machine direction, i.e. the path of travel of the bags, is such that the seal  136  precedes the serration  138 ; that is, the seal is positioned downstream of the serration. Alternatively, the serration  138  can precede the seal  136 . 
   As shown in  FIG. 15 , bag  134  is constructed with a through cut that forms a tab  140 , which hinges around reference line  142 . Although the tab  140  and reference line  142  are shown as rectangular, any suitable geometry can be employed. Bag registration for further machine processes, such as printing, and/or separation of a bag from the next sequential bag in the series of bags, can be accomplished by sensing the tab  140  with proximity switch  144  as the tab passes over the exit end of air line  146 . A registration signal is thus generated. The tab  140  is sensed because the air pressure from air line  146  forces the tab above the plane of the bag  134 , where the tab can be sensed by the proximity switch  144 . 
   In another embodiment, the bag  134  can be used instead of the elongated hole portion of serration  126 . Thus, as the tab  140  passes over the exit end  132 , a drop in air pressure can be observed at  128 . 
   The embodiment of  FIGS. 14 to 18  can be beneficially used with a variety of bag types, including patch bags, and bags without patches. An additional advantage of this embodiment is that the through cut that forms the tab  140  provides an opening for the release of trapped air during winding in the manufacturing process. 
   In alternative embodiments of the present invention: 
   An ink jet printer may be used as an alternative to the thermal transfer printer discussed above. The printer can be activated as the web advances, or alternatively can traverse in the web cross direction during a dwell. 
   A seal bar can be incorporated below the web selector  12  with an intermediate knife system. This would be useful where the web is in the form of a lay flat tube. 
   A seal bar can be incorporated above the web selector  12  with an intermediate knife system. This would be useful where the web is in the form of a lay flat tube. 
   The web transfer device can be eliminated, resulting in a manual system. 
   The invention is described with the web dispenser selectively drawing webs from an overhead bank of rolls of webs, and with the stationary and pivoting drive rolls arranged in a horizontal position. Likewise, the final bag position is shown as being horizontal. By modifying or rearranging one or more components of the invention, the rolls of webs, the web dispenser, and the other components of the invention can be arranged in any suitable orientation or configuration, and any final bag orientation is obtainable. 
   Major motion of the bag transfer device is rotational. Combining with a linear component results in a greater degree of flexibility benefiting applications such as transferring the bag to a stuffing horn. 
   The invention provides a practical resolution to the problem of how to select from multiple sources, optionally print, and stage discrete bags. 
   Problem resolution is achieved in a compact module. Utilizing roll-serrated bags the location of the web free ends are initially held in close proximity thus selection and movement through the print station require very little space. 
   The invention uses in one embodiment roll serrated bags that typically have less seal pucker and wrinkles as opposed to taped bags. This characteristic presents a more uniform surface for applying print. 
   The invention uses roll serrated bags, a more compact format than taped bags. Typically diameters of rolls of serrated bags are about 30% less than roll taped bags. 
   The invention controls web tension during printing. 
   The invention is capable of printing either side of the bag. 
   Any films, especially thermoplastic films such as olefinic films with or without oxygen barrier functionality, can be used with benefit in this invention. These films are made by extrusion coating, coextrusion, lamination, or other suitable processes. Especially preferred for many applications are films comprising an outer layer, an intermediate layer, and an inner layer. The materials of the outer layer are often chosen for abuse resistance and/or sealability, and can be chosen from any suitable polymeric materials such as polyolefins, especially ethylenic polymers and copolymers, polypropylene, polyesters, polyamides, and the like. The inner layer materials, often chosen for sealability, can be any of the materials described for the outer layer. The intermediate layer materials are often chosen for their barrier qualities (i.e. barriers to oxygen, moisture, carbon dioxide, etc.). Preferred materials include polyvinylidene chloride polymers and copolymers, ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyamide, polyester, acrylonitrile, and the like. Bags are preferably heat shrinkable, and preferably at least partially crosslinked. 
   It is to be understood that variations of the present invention can be made without departing from the scope of the invention, which is not limited to the specific embodiments and examples disclosed herein, but extends to the claims presented below. 
   For example, although the center moveable roll is described herein as a roll that moves to left or right on a pivot point, those skilled in the art will appreciate that any motive device can be used to bring the center moveable roll into contact with a web and nip the web against a stationary roller. An example would be a pneumatic or hydraulic piston, a gear system, or an electro-mechanical actuator.