TECHNICAL FIELD
The invention relates generally to the packaging industry and, more specifically, to application of stretch film or wrap to objects.
BACKGROUND
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'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.
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.
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'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
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.
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.
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
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:
FIG. 1 comprises a perspective view of a prior art stretch film dispenser;
FIG. 2 comprises a perspective view of an example stretch film dispenser as configured in accordance with various embodiments of the invention;
FIG. 3 comprises a top view of the example stretch film dispenser of FIG. 2;
FIG. 4 comprises a side view of the example stretch film dispenser of FIG. 2;
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;
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;
FIG. 7 comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention;
FIG. 8 comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention;
FIG. 9 comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention;
FIG. 10 comprises a perspective view of another example stretch film dispenser as configured in accordance with various embodiments of the invention; and
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;
FIG. 12 comprises a top view of the example stretch film dispenser of FIG. 11;
FIG. 13 comprises a side view of the example stretch film dispenser of FIG. 11;
FIG. 14 comprises a perspective view of an example rotatable member with projections as configured in accordance with various embodiments of the invention;
FIG. 15 comprises a side view of the example member of FIG. 14;
FIG. 16 comprises a top view of the example member of FIG. 14;
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;
FIG. 18 comprises a top view of the example stretch film dispenser of FIG. 17;
FIG. 19 comprises a side view of the example stretch film dispenser of FIG. 17;
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;
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
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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'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's path to provide additional stretch in the film's length and to stabilize the film'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.
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.
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.
Another example application of this subject matter is in applying the protrusions to bi-axially stretch the stretch film during the stretch film'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'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.
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.
Patent Application
20140109524
