Patent Publication Number: US-11661225-B2

Title: Center divider for shrink oven

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application, Ser. No. 62/743,805, filed on 10 Oct. 2018. This Provisional Application is hereby incorporated by reference herein in its entirety and is made a part hereof, including but not limited to those portions which specifically appear hereinafter. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates generally to product packaging and, more particularly, to product packaging using an oven to shrink wrap a shrink wrap material about products. 
     Description of Prior Art 
     It is known to provide a wrap of material about products such as to facilitate or otherwise improve product handling, transport and the like. To that end, it has become common to wrap product with a tube of heat shrink wrap film and then apply heat to effectively shrink the wrap about the product such as to form a packaged product. A common example of product so wrapped includes a plurality of articles such as beverage bottles or like containers. 
     As will be appreciated, the resulting package product can result in a grouping of a plurality of articles that can be more easily or conveniently handled or transported, such as may include facilitating such handling or transporting via mechanical devices, for example. Further, the packaging can desirably prevent or avoid undesirable product contact such as by debris, dirt, dust and the like, for example. 
     The heating of a product wrapped with a tube of heat shrink wrap film is often conducted in an apparatus sometimes referred to a shrink wrap oven or tunnel. Typically, a load of product wrapped with a tube of heat shrink wrap film is introduced into the shrink wrap oven or tunnel via a conveyor passing through the shrink wrap oven or tunnel. As the load is passed through the shrink wrap oven or tunnel, heat such as supplied by a heater device is applied to the load via a blower with the heat acting to shrink the film through convection. 
     In current practice, such shrink wrap ovens or tunnels are typically placed just after another machine that groups articles together and wraps them in the heat shrinkable film. The film is wrapped around the product and either welded with a seam or the film overlaps underneath and must be welded in the shrink wrap oven or tunnel. At this point the film loosely covers the group of articles and must be shrunk with heat. 
     There are current ovens that include an air box with a series of holes to discharge the air. The air box can include a component hung from the top, and can be mounted so it can be moved from the middle of the oven to the side. This requires the upper component to be used on the side for single track packages and can compromise the quality of the package. Furthermore, the box typically is feed with flexible hoses for the hot air which require maintenance. In addition, the holes on either side of the upper component often create a turbulent airflow that will often cause the film to flutter and contact the package prematurely. 
     In view of the above, there is a need for an improved heat shrink wrap product packaging apparatus and methods. 
     SUMMARY OF THE INVENTION 
     A general object of the invention is to provide an improved heat shrink wrap product packaging apparatus and methods. 
     Embodiments of this invention include a swing divider for providing hot air, such as mounted on large solid ducts over the top of an oven conveyor. The solid ducts eliminate the need for maintenance, and can include a large center duct box to control the air to the swing divider. The divider can be hinged to the duct box, so it can swing to a vertical position between packages in a dual track on the conveyor. The divider can also swing to a retracted, horizontal position above the packages to run a single product track. The divider typically is only used for dual track, so the oven air flow does not have to be compromised for single track. 
     Additionally or alternatively, embodiments of this invention include a center divider with a generally continuous lower opening and a deflector below the divider. The deflector converts the jets of air from the lower end of the deflector into one or more smooth air flows. This smooth air flow prevents the film from fluttering and can cause it to inflate like a bubble, making a tighter and a better-looking package. This also can eliminate necessary adjustments. 
     In accordance with one aspect of the invention, an improved apparatus for heat shrink wrap product packaging is provided. In some embodiments, such an apparatus includes first and second opposed and spaced apart side wall assemblies. The first and second side wall assemblies define a longitudinally extending product conveyance path therebetween. The apparatus includes a conveyor to move product along the conveyance path. Each of the side wall assemblies can include an inner wall spaced apart from an outer wall and define or include an air flow duct therebetween. Each of the inner walls desirably includes an array of spaced apart air discharge openings directed towards and associated with the product conveyance path. The apparatus further includes at least one heater/blower assembly disposed in the apparatus. The at least one heater/blower assembly is in heated air flow communication with the air flow duct of each of the side wall assemblies. A cover assembly is included and is disposed over and at least in part enclosing at least a section of the product conveyance path and at least a portion of the array of spaced apart air discharge openings directed towards and associated with the product conveyance path from the first and the second side wall assemblies. 
     Embodiments of the apparatus include a center divider extending above the conveyance path between the first and second opposed and spaced apart side wall assemblies. As used herein, “center” refers to a position between the side walls, and is not limited to an exact center equidistant between the side walls. The center divider of this invention can be a swing divider that moves between a retracted position and a vertical position dividing the conveyance path from a single track to a dual track conveyance path. The center divider can be connected to an upper duct system by a rotation connection, such as a hinge. 
     In embodiments of this invention, the center divider, such as a swing or other divider, includes an internal air passageway and a deflector mechanism in combination with the center divider to direct the air flow laterally across the conveyance path. Desirably, the air flow from the deflector mechanism includes two oppositely directed jets of air laterally across the conveyance path, such as each toward one of the side walls. The deflection mechanism can include a curved deflector at a lower air outlet end of the center divider, such as curved on each side toward a corresponding one of the side walls. An internal air passageway of the center divider can reduce in diameter from an inlet to the outlet end to funnel air to a curved deflector that divides the air from the outlet end into two lateral jets of air. 
     In accordance with another aspect of the invention there is provided an improved method for shrink wrapping a product to form a packaged product. In one embodiment, such a method involves conveying product wrapped with a tube of heat shrink wrap film on a conveyor where the conveyor forms a conveyance path disposed between first and second opposed and spaced apart side walls. Streams of heated air are projected from the first and second opposed and spaced apart side walls and toward the wrapped product on the conveyance path. The projection of the streams of heated air from the first and second opposed and spaced apart side wall assemblies and toward the wrapped product on the conveyance path are advantageously controlled by to shrink the tube of film onto the product to form the packaged product. 
     In some embodiments of this invention, the method further includes: conveying a product wrapped with a tube of heat shrink wrap film along the conveyance path with a center divider in the retracted position; lowering the center divider into the vertical position to form dual track paths on the conveyance path; conveying a pair of further products each wrapped with a tube of heat shrink wrap film along the conveyance path, with the center divider disposed between the pair of further products; and projecting streams of heated air from the center divider toward each of the pair of further products. In some embodiments of this invention, the method alternatively or additionally further includes: conveying a pair of products each wrapped with a tube of heat shrink wrap film along the conveyance path, with the center divider disposed between the pair of products; projecting streams of heated air from an end of the center divider; and deflecting the heated air from the end laterally toward a side of each of the pair of further products facing the center divider. 
     Other objects and advantages will be apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an apparatus for heat shrink wrap product packaging according to one embodiment of this invention. 
         FIG.  2    is a simplified sectional view along the line  2 - 2  shown in  FIG.  1   . 
         FIG.  3    is a simplified sectional perspective view along the line  2 - 2  shown in  FIG.  1   , in a retracted position. 
         FIG.  4    is a simplified sectional perspective view along the line  2 - 2  shown in  FIG.  1   , in a non-retracted position. 
         FIG.  5    is a simplified sectional view of an apparatus for heat shrink wrap product packaging in according to one embodiment of this invention. 
         FIGS.  6  and  7    show a divider according to embodiments of this invention. 
         FIG.  8    shows a perspective section view of the apparatus of  FIG.  5   . 
         FIGS.  9  and  10    each show an operation of the apparatus of  FIG.  5   . 
     
    
    
     It is to be understood that in the drawings, like reference characters designate like or corresponding parts throughout the several views. It is to be further understood that certain standard elements not necessary for an understanding of the invention may have been omitted or removed from the drawings and description for purposes of facilitating and enhancing illustration and/or comprehension. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The subject development provides improved heat shrink wrap product packaging apparatus and methods. 
       FIG.  1    illustrates an apparatus, generally designated by the reference numeral  110 , for heat shrink wrap product packaging according to one aspect of the subject development. The apparatus  110  is of a type such as can be referred to as a shrink or shrink wrap oven or tunnel and through which product wrapped in plastic film is conveyed to shrink, e.g., heat shrink, the film to form a packaged product. 
     In an effort to enhance understanding and appreciation of the subject invention development, the drawings have been simplified and the description has been focused on distinguishing features. Thus in the drawings and associated description, normal or customary items for shrink or shrink wrap ovens or tunnels may not herein be specifically identified and discussed. 
     While beverage bottles or like containers are an example of a common product that can be so processed to form a packaged product, those skilled in the art and guided by the teachings herein provided will understand and appreciate that the broader practice of the subject development is not necessarily so limited and a wide range of products such as known can, if desired, be suitably processed using the apparatus and methods herein provided. 
     The apparatus  110  includes first and second opposed and spaced apart side wall assemblies  112  and  114 . The first and second side wall assemblies  112  and  114  defining a longitudinally extending product conveyance path  116  therebetween. The apparatus  110  includes a conveyor  150  to move product along the conveyance path  116  longitudinally extending between the side wall assemblies  112  and  114 , respectively. As explained further below, the conveyance path of embodiments of this invention can be a single track, a double track, and/or alternate from one to the other, as may be desired for a particular application. 
     As will be appreciated, an apparatus such as herein provided can desirably be sized and adjusted to appropriately accommodate variously sized product packages. For example, an apparatus according to one preferred embodiment, permits or accommodates processing of a package measuring 17 inches high and 38 inches wide. Further, an apparatus according to one preferred embodiment, has a capacity or permits processing of, without limitation, 100 cases of product packages per minute. 
     Each of the side wall assemblies  112  and  114  include an inner wall  120  spaced apart from an outer wall  122  and defining or including an air flow duct  124  therebetween to form what is sometimes referred to as an air box. Each of the inner walls  120  can include an array of spaced apart air discharge openings  126  that are directed towards and associated with the product conveyance path  116 . The first and second side wall assemblies  112  and  114  each include an optional airfoil element  130 , such as discussed in U.S. patent application Ser. No. 15/876,826, for air flow control from the air discharge openings  126  in the respective inner wall. 
     The apparatus  110  further includes a heater/blower assembly, generally designated by the reference numeral  140 . The heater/blower assembly  140  can suitably include a blower and a heating element or device, such as known in art, for example. Heating elements or devices for use according to certain embodiments can suitably be or take the form of being gas-powered or electric-powered, as may be desired for a specific or particular application. The apparatus  110  further includes suitable conduits or connections such as may form a plenum including air flow ducts such that the heater/blower assembly  140  is in heated air flow communication with the air flow duct of each of the side wall assemblies  112  and  114 , respectively. 
     The apparatus  110  also includes a cover assembly  160 . As shown, the cover assembly  160  is desirably disposed over and at least in part encloses at least a section of the product conveyance path  116  and at least a portion of the array of spaced apart air discharge openings  126  directed towards and associated with the product conveyance path  116  from the first and the second side wall assemblies  112  and  114 , respectively. The cover assembly  160  includes a top portion  164  and opposed lateral side wall portions  166  and  168  such as to enclose the corresponding section of the product conveyance path  116 . In accordance with on preferred embodiment, the cover assembly desirably is of a monocoque construction. As will be appreciated by those skilled in the art and guided by the teachings herein provided, the incorporation and use of a cover assembly of monocoque construction can one or more of: eliminate welding, reduce weight and/or reduce costs. 
     The apparatus of this invention incorporates a divider element to divide the conveyor into a double track conveyor, and/or to provide a better hot air flow over the conveyed products. The divider element typically extends from a top inner surface of the oven and above the conveyor.  FIGS.  2 - 4    illustrate a divider element, namely center divider  200 , extending above the conveyance path  116  and between the first and second opposed and spaced apart side wall assemblies  112  and  114 . 
     The center divider  200  is connected to the heater/blower assembly  140  to deliver hot air to the conveyance path  116 . The center divider  200  can receive the hot air via any suitable mechanism, such as flexible hoses, but desirably is connected to solid, rigid air flow duct  124 . The center divider  200  includes an internal air passageway  202  in combination with the duct  124 , and that delivers hot air to lateral openings to provide hot air streams  205  across the conveyance path  116 . Any suitable opening array can be used on the side walls of the central divider, depending on need. 
     As shown in  FIG.  2   , the center divider  200  is a swing divider that moves between a vertical, dual track position (disposed between two package tracks) of  FIGS.  2  and  4    and the retracted, single track position of  FIG.  3   . The swing divider  200  is connected to the oven by a rotation connection, such as a hinge  210  connected to the duct  124 . In  FIGS.  2 - 4   , the hinge  210  connects an edge of a first end  204  of the swing divider  200  to a central duct structure  125  extending longitudinally above and along the conveyance path  116 . The central duct structure  125  includes an air outlet  128  that corresponds with an air inlet of the divider first end  204 . The air outlet  128  can be a simple opening that releases air in the retraced position over a single track of  FIG.  3   , includes a cover or diffuser element that moves into place upon the retraction of the center divider  200 , and/or otherwise includes a valve structure to control the air through the outlet  128 . 
     Any suitable mechanism can be used to swing the divider  200  to the retracted position. In the embodiment of  FIGS.  2 - 4   , a mechanical linkage  220  and an electric motor  222  move the swing divider  200  between the two positions. A curved arm  224  extends from the divider  200  about the hinge  210  to connect to a second arm  226 . The second arm  226  extends to the electric motor  222 , and rotational movement of the motor  222  moves the second arm  226 , which moves the end of the curved arm  224  causing the divider  200  to translate the linear motion of the second arm  226  to rotational movement about the hinge  210 . 
     The central divider  200  can thus be moved from a retracted position shown in  FIG.  3    to the vertical position of  FIGS.  2  and  4   . As shown in  FIG.  3   , the retracted position provides a single rack conveyance path  116  for a single track of products  100 .  FIG.  4    shows the dual track conveyance path, with the divider  200  extending between a pair of products  100 , and laterally providing air streams toward each of the two products  100 . 
       FIGS.  5 - 10    illustrate a center divider  200  according to another embodiment of this invention, including a deflector mechanism  230 . As shown, the center divider  200  is also a swing divider, operating in a similar manner to that of  FIGS.  2 - 4   , but the deflector mechanism can be used in other non-swinging, or stationary, center dividers as well. 
     As shown in  FIGS.  5  and  6   , the center divider  200  includes an internal air passageway  202  extending from an air inlet at a first end  212  to an air outlet at an opposite second end  214 . The first end  212  is abutting duct outlet  128 , which is connected to the duct system  124 , as shown in  FIG.  8   . The internal air passageway  202  of the center divider  200  reduces in diameter from the inlet to the outlet end. As shown in  FIG.  7   , the center divider  202  can be formed of several adjacent divider subsections, with a plurality of swing mechanisms, as needed, extending along the length of the oven and/or conveyance path  116 . 
     The deflector mechanism  230  extends beyond and/or below the air outlet of the second end  214 . The deflector mechanism includes a linear extension  232  that extends from the second end  214 , and divides air outlet into two outlet sections, one on each side of the linear extension  232 . The linear extension is shown in  FIG.  6    as extending through the entire air passageway  202 , but can vary in configuration, as well as length beyond the second end  214 , depending on need. 
     As shown in  FIGS.  5  and  6   , the deflector mechanism  230  divides the air flow into two opposite, lateral jets of air, each directed across the conveyance path  116  toward the side assemblies  112  and  114 , respectively. The illustrated deflector mechanism  230  includes a curved deflector  234  at an end of the linear extension  232 . The deflector  234  includes curved surface extending in opposite directions, respectively, toward each of the first and second side wall assemblies  112  and  114 . As shown in  FIGS.  5  and  6   , the curved deflector  234  divides the air from the outlet end into two lateral jets of air  205 . 
     As shown in  FIG.  9   , the lateral jets of air can be directed to a side of the products opposite the air from the oven air discharge openings  126 . The center lateral air jets of this invention, along with the funneled air of the cone-shaped divider, provide an improved smooth air flow that prevents the film from fluttering and/or inflating like a bubble, resulting in a tighter and/or a better-looking final package.  FIG.  10    illustrates the center divider  200  swung into the retracted position to provide a single track conveyor, such as according to the method and components discuss above. 
     Thus the invention provide a flexible use, single/dual conveyance path with improved air flow. In additional the rigid duct structure reduces maintenance over current flexible hose systems. 
     It is to be further understood and appreciated that the numerous above-identified and/or described features of the subject product packaging apparatus and methods can be appropriately practiced alone or individually or in various combinations as may be desired for a particular or specific application. 
     Those skilled in the art and guided by the teachings herein provided will understand and appreciate that the broader practice of such aspect of the subject development is not necessarily limited to devices so constructed or operated as devices of alternative construction or operation can, if desired, be appropriately incorporated and utilized herewith. 
     The invention illustratively disclosed herein suitably may be practiced in the absence of any element, part, step, component, or ingredient which is not specifically disclosed herein. 
     While in the foregoing detailed description this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purposes of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.