Abstract:
A stretch wrap applicator includes a member designed to engage the stretch wrap or stretch film as it is dispensed and to deform the stretch wrap by creating additional pockets of stretch on the stretch wrap transverse to its plane. The additional deformations caused by the member engaging the stretch wrap whether done in-line using the applicator or offline using equipment effects an additional stretch of the stretch film during application beyond the typical stretch caused by tension on stretch wrap when being applied to an object.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional patent application No.  61 / 716 , 666  filed Oct.  22 ,  2012 , which is incorporated by reference herein in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates generally to the packaging industry and, more specifically, to application of stretch film or wrap to objects. 
       BACKGROUND 
       [0003]    Stretch film or wrap is generally known in the industry as a material that can be used to securely wrap a collection of objects together using the stretch material&#39;s resiliency and clinginess. Stretch wrap is typically understood to be a polyethylene stretch film that is generally dispensed from a roll form for use in a variety of applications. For instance, stretch wrap is held against a collection of objects and dispensed and stretched around the collection of objects and wrapped over itself up to several times to cover and hold together the collection of objects. In the shipping industry, for example, a collection of materials may be placed on a pallet to secure such articles together during the shipping process. A collection of boxes placed on a pallet can be shipped as a single cohesive unit when bound together through wrapping with stretch wrap. Other applications of stretch wrap are known such as wrapping leftover food or simply binding together a collection of items. 
         [0004]    Although such usages for stretch wrap are well known and documented, the amount of stretch wrap used in any given application can be extensive. For example, for an industrial supplier that ships large numbers of pallets of materials out on a consistent basis, a large inventory of stretch wrap must be maintained to facilitate the regular shipment of such products. For example, a large amount of stretch film may be necessary to wrap a given pallet of materials. 
         [0005]    Typically, during application, a tension is applied to the stretch film as it is applied to the objects being wrapped. This tension stretches the film to facilitate a secure binding of the wrapped objects together. In typical approaches, the stretch creates a lengthening of the stretch wrap, but also creates significant narrowing of the stretch wrap in the direction not under tension. The narrowing causes less coverage of the object being wrapped and eliminating much if not all of the efficiency gained in stretching the stretch wrap. Most known devices work by rotating the film around a spindle core while tension is applied to the core of the stretch film to create drag so that when the stretch film unrolls it is stretched tight around the package. Another known device includes an idler roller that engages and rotates with the stretch wrap as it is pulled from its roll. The idler roller facilitates stretching of the wrap along its length due to the tension on the film. The roller also generally maintains the film&#39;s flat shape as it engages the object around which it is being wrapped. Although this stretch is advantageous, some narrowing does occur and further stretch and strength is still desirable. Another known approach is to stretch the stretch wrap with tension in the long direction while holding the sides of the stretch wrap to reduce narrowing. Such an approach is largely done through complex and expensive machinery. 
       SUMMARY 
       [0006]    Generally speaking and pursuant to these various embodiments, a stretch wrap manipulator is provided that includes one or more members arranged, for instance, in series and designed to engage the stretch wrap to deform it by locally pushing a part of the stretch wrap transverse to its plane. The additional deformations or perforations caused by the one or more members engaging the stretch wrap effects additional strength and stability in handling the stretch wrap and an additional stretch of the stretch film during application above and beyond the typical stretch of the stretch wrap when being applied to an object. 
         [0007]    In one described example, an idler roller that stretches and maintains the stretch wrap flat in previous devices is adapted to include protrusions that engage the stretch wrap and further stretch the stretch wrap locally where the stretch wrap engages the protrusions. This additional stretching caused by the engagement of the protrusions on the stretch wrap can effect a significant increase in the stretch of the stretch wrap. 
         [0008]    The increase in stretch and strength of the stretch wrap is effected largely through bi-axially applied stretch through use of the protrusions rather than stretch in just one direction through the use of prior devices using strictly smooth members or no member at all. So configured, efficiency of use of the stretch wrap increases. These and other benefits may become clearer upon making a thorough review and study of the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The above needs are at least partially met through provision of the stretch wrap dispenser described in the following detailed description, particularly when studied in conjunction with the drawings, wherein: 
           [0010]      FIG. 1  comprises a perspective view of a prior art stretch film dispenser; 
           [0011]      FIG. 2  comprises a perspective view of an example stretch film dispenser as configured in accordance with various embodiments of the invention; 
           [0012]      FIG. 3  comprises a top view of the example stretch film dispenser of  FIG. 2 ; 
           [0013]      FIG. 4  comprises a side view of the example stretch film dispenser of  FIG. 2 ; 
           [0014]      FIG. 5  comprises a side view of stretch film pulled from a roll of stretch film using a stretch film dispenser similar to that of  FIG. 1 ; 
           [0015]      FIG. 6  comprises a side view of stretch film dispensed from a roll of stretch film using a stretch film dispenser configured in accordance with various embodiments of the invention; 
           [0016]      FIG. 7  comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention; 
           [0017]      FIG. 8  comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention; 
           [0018]      FIG. 9  comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention; 
           [0019]      FIG. 10  comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention; and 
           [0020]      FIG. 11  comprises a perspective view of an example stretch film dispenser that can pierce a film as configured in accordance with various embodiments of the invention; 
           [0021]      FIG. 12  comprises a top view of the example stretch film dispenser of  FIG. 11 ; 
           [0022]      FIG. 13  comprises a side view of the example stretch film dispenser of  FIG. 11 ; 
           [0023]      FIG. 14  comprises a perspective view of an example rotatable member with projections as configured in accordance with various embodiments of the invention; 
           [0024]      FIG. 15  comprises a side view of the example member of  FIG. 14 ; 
           [0025]      FIG. 16  comprises a top view of the example member of  FIG. 14 ; 
           [0026]      FIG. 17  comprises a perspective view of an example stretch film dispenser having two members engaging the film as configured in accordance with various embodiments of the invention; 
           [0027]      FIG. 18  comprises a top view of the example stretch film dispenser of  FIG. 17 ; 
           [0028]      FIG. 19  comprises a side view of the example stretch film dispenser of  FIG. 17 ; 
           [0029]      FIG. 20  comprises a perspective view of a pallet with objects being wrapped with stretch wrap using an example stretch wrap dispenser configured in accordance with various embodiments of the invention; 
           [0030]      FIG. 21  comprises a perspective view of a pallet with objects being wrapped with stretch wrap using an example stretch wrap dispenser configured in accordance with various embodiments of the invention; and 
           [0031]      FIG. 22  comprises a perspective view of a partial apparatus for pre-stretching and re-rolling a stretch film in accordance with various embodiments of the invention. 
       
    
    
       [0032]    Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein. 
       DETAILED DESCRIPTION 
       [0033]    Referring now to the drawings and, in particular to  FIG. 1 , a prior art stretch film dispenser  100  is illustrated. The stretch film dispenser includes a frame having a handle  105  extending from the frame, a rotatable support  115  is configured to engage and hold a roll  120  of stretch film and rotate with the roll  120  as the stretch film  125  is pulled and removed from the roll  120 . The rotatable support or arm  115  is rotatably supported by the frame  105  using ball bearings or other rotatable supports as known in the art. The frame  105  also supports an elongated member  130  that extends next to the roll  120  and is disposed to engage the stretch film  125  as it dispenses from the roll  120 . In use, the stretch film  125  engages an object to be wrapped and is kept in tension as the stretch film is dispensed from the roll  120  and applied to the object. The tension on the stretch film  125  stretches the stretch film  125  along its length as it is dispensed from the roll  120 . The elongated member  130  facilitates stretching of the stretch wrap  125  as it engages the stretch wrap  125  during dispensing. 
         [0034]      FIG. 2  illustrates an example stretch film dispensing apparatus  200  for applying a stretch film to an object. The stretch film dispensing apparatus  200  includes a support frame  205 , including an extension handle  210  that facilitates manual application of stretch film to an object. The frame  205  can be made of any suitable material such as a metal such as steel or plastic having sufficient strength to support the various aspects of the stretch film dispenser  200  against the forces experienced during stretch film application. One of skill in the art will recognize that the teachings of this disclosure are not limited to hand application of stretch film and may be applied to mechanical or automatic application of stretch wrap or film to objects. A support  215  is configured to support a roll  220  of stretch film and dispense the stretch film in response to tension on the stretch film  225 . The support  215  may be a rotatable arm or an elongated element designed to engage a hollow center of a stretch film roll, gripping members designed to engage either end of a stretch film roll, or other design suitable to support a roll of stretch film for dispensing. 
         [0035]    The frame  205  also supports at least one member  230  having protrusions  233  configured to engage the stretch film  225  after the stretch film  225  extends from the roll  220  and before the stretch film  225  contacts the object. The protrusions  233  are configured to distort or variably stretch the stretch film  225  along a length of the stretch film  225  engaging the at least one member  230 . In the example of  FIG. 2 , the at least one member is disposed generally parallel to the roll  220  and is an elongated rotatable member that is cylindrical with the protrusions extending out from a radius of the cylinder. The frame  205  in the illustrated example supports the member  230  in a rotatable fashion using roller bearings or other suitable means known in the art such that the member  230  rotates as the stretch film  225  is dispensed and rolls over the member  230 . In this way, the protrusions  233  engage and release the stretch film  225  to deform it as the member  230  rolls with the dispensed stretch film  225 . The member  230  can be formed out of any of a variety of materials having sufficient stiffness to deform the stretch film. For example, the member  230  can be a pre-formed plastic piece to reduce adhesion between the stretch wrap and the member  230 . Also, the member  230  can have any of a variety of cross sectional shapes or be irregularly shaped including optionally protrusions that intentionally pierce the film to give it extra elongation or some type of ventilation. The protrusions also can have a variety of forms as discussed below. These protrusions could also be applied off line during the manufacturing of the stretch film. 
         [0036]    In operation, the dispensing apparatus  200  performs a method for applying a stretch film to an object including engaging the stretch film  225  being dispensed from the dispenser  200  with the at least one member  230  having protrusions  233  to variably stretch the stretch film  225  along a length of the stretch film  225  engaging the at least one member  230 . Maintaining tension on the stretch film  225  during engagement with the at least one member  230  effects additional stretch on the stretch film  225  before application to an object. For example, as shown in  FIGS. 5 and 6 , stretch film  125  dispensed from a stretch film dispenser such as that illustrated in  FIG. 1  will have a stretched length  550  of a given amount with the length being defined from a point of engagement  570  with the rotatable member  130  to an end portion of the stretch film  125 .  FIG. 6  illustrates a same amount of stretch film  225  dispensed from a dispenser like that illustrated in  FIGS. 2-4  having a tension similar to that of the stretch film dispensed as illustrated in  FIG. 5 . The stretch of the stretch film  225  illustrated in  FIG. 3  at  650 , illustrates that the additional stretching of the stretch film through engagement with the protrusions  233  in combination with the tension applied during application allows the stretch film  225  to stretch out up to at least 15% more as compared to using a prior stretch film application device. 
         [0037]    Generally speaking, when the protrusions  233  engage the stretch film  225 , the protrusions locally stretch a portion of the stretch film  225  transverse to the plane of the stretch film  225 . In contrast to the stretching of the film that is entirely in the plane of the stretch film  225  such as when the stretch film is applied using a dispenser like that of  FIG. 1 , stretch film being applied using a device such as that of  FIGS. 2-4  is additionally stretched in the transverse direction. This transverse action bi-axially orients the film to improve its strength and increasing its area of coverage. The extra stretch in the transverse direction in turn produces an additional stretch in the length of the stretch film  225  when a tension is provided laterally on the stretch film  225 . 
         [0038]      FIGS. 7-10  illustrate additional examples of the types of protrusions and/or patterns of protrusions that can be used to provide a transverse stretching of the stretch film as it is being dispensed from a roll. As illustrated, the protrusions can come in any of a variety of shapes and sizes designed to effect a stretch and/or piercings in the stretch film transverse to the plane of the stretch film. The examples of  FIGS. 7-10  can be modified in a variety of ways to effect such stretching. For example, the protrusions may come in regular or irregular patterns. 
         [0039]      FIGS. 11-13  illustrate another example type of protrusion array designed to pierce the stretch film as it is dispensed from a roll. In this example, the protrusion  1133  includes a leading, curved edge  1170  that initially engages and stretches the film as it engages the member  1130 . As the film progresses past the rotating member  1130 , the protrusion  1133  rotates further into the film until a pointed end  1180  of the protrusion  1133  pokes through the tensioned film to create a piercing  1190 . So configured, an array of piercings  1190  are created in the film while at the same time the film is stretched as described above. In this approach, the benefits of stretching the film are achieved together with providing a way to allow air circulation through the film after it is applied to an object. One skilled in the art will recognize that other particular shapes of protrusions can be used to pierce the film. Moreover, combinations of different types of protrusions can be used on a single member for engaging the film. For instance, one set of protrusions may be designed to pierce the film, and a second set of protrusions can be designed to only stretch the film so that the processed film includes both stretched portions and pierced portions. 
         [0040]    For example,  FIGS. 14-16  illustrate another example type of protrusion designed to pierce the stretch film. In this example, the rotatable member  1430  includes two pieces  1431  and  1432  mated together along a seam  1435 . The protrusions  1433  include a jagged edge designed to pierce the stretch film when the film engages the protrusions  1433 . Such a design does not stretch the film as much as other protrusion designs before piercing the film. Many such designs are possible for the protrusions. 
         [0041]    Moreover, additional members including protrusions may be used to engage the stretch film as it is dispensed from the dispenser. For example, a second roller having protrusions may be placed along the stretch film&#39;s path extending from the dispenser before engaging the object.  FIGS. 17-19  illustrate one such example approach to having two rollers or members engaging the film. The first roller  1730  includes protrusions  1733  to engage the film as the film separates off of its roll to stretch or pierce the film as described above. The second roller  1732  is disposed in the film&#39;s path to provide additional stretch in the film&#39;s length and to stabilize the film&#39;s width to provide additional protection against necking of the film. The second roller may or may not include protrusions. In one such approach shown in  FIG. 19 , the second roller  1732  includes protrusions  1783  designed to engage the stretch wrap in a pattern to largely not overlap with portions of the stretch film that engage protrusions of a first member engaging the stretch film. Other combinations of protrusions between two or more rollers designed to engage the stretch film are possible. 
         [0042]    An example application for dispensing stretch film from a stretch film dispenser such as accordingly to the teachings of this disclosure is shown in  FIG. 20 . The pallet  2005  supports a plurality of boxes  2010  for shipping. After an end of the stretch film is secured to the boxes  2010 , a person holds and pulls the frame of the dispenser  2000  along the surface of the boxes  2010 , effectively pulling the film  2025  from the roll  2020  over the idler roller  2030 . The dispenser  2000  continues to pull the stretch film  2025  around the boxes  2010  to wrap and bind the boxes  2010  together for stability during shipping. The dispenser  2000  includes an idler roller  2030  having protrusions  2033  configured to engage the stretch film  2025  and stretch it along its length through application of tension and in a direction transverse to the length of the stretch film  2025  through engagement of the protrusions  2033  on the stretch film  2025 . So configured, the stretch film  2025  exhibits an improved stretch and can cover more of the boxes using less stretch film  2025  from the roll  2020 . Thus, less stretch film  2025  is needed to securely wrap the boxes  2010  on the pallet  2005 . 
         [0043]    Another application is illustrated in  FIG. 21  where the roll  2120  of stretch film is mounted to a frame  2105  supported by a larger apparatus  2110 . In this case the larger apparatus  2110  is configured to move the roll  2120  up and down relative to the boxes  2170  stacked on a pallet  2175 . The apparatus  2110  cooperates with a rotation mechanism  2190  configured to rotate the pallet  2175 . After an end of the stretch film is secured to the boxes  2170 , the rotation of the pallet  2175  pulls the stretch film from the roll  2120 . A roller with protrusions is disposed next to the roll  2120  to engage the tensioned stretch film as it leaves the roll  2120  and before it engages the boxes  2170 . Such an auto-wrapping device is known in the art and needs no further explanation. The apparatus  2110  can be modified to include a mechanism to modify the tension on the stretch film as it is applied the boxes  2170 . 
         [0044]    Another example application of this subject matter is in applying the protrusions to bi-axially stretch the stretch film during the stretch film&#39;s preparation and prior to its being rolled onto a roll for dispensing. In one example of this approach, one or more members like that described above can be disposed to engage stretch film just before the stretch film is rolled up. One such example is illustrated in  FIG. 22 . In the illustrated example, stretch film is unrolled from a first roll  2220  over a first roller  2225  that stretches the film along its length. A second roller  2230  then engages the film with protrusions  2233  to stretch the film locally and transverse to the plane of the stretch film. This can also be achieved as the film is coming off of the stretch film extruder in series with rollers attached to the machinery. The stretched film is then re-rolled onto a second roll  2250  for storage for later use. Mechanisms can be built to support the rolls  2220  and  2250  and rotate them to effect the stretch film&#39;s engagement of the rollers  2225  and  2230 . The roller  2225  and  2230  may have any combination of protrusions or not, depending on the type of stretch or piercing desired for a given pre-stretched film. Such pre-stretched stretch film can then be applied using a prior applicator such as that of  FIG. 1  while maintaining much of the advantageous described above. 
         [0045]    Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.