Patent Publication Number: US-2009235617-A1

Title: Wrapping apparatus having top loading and threading film dispenser

Description:
This application claims priority under 35 U.S.C. § 119 based on U.S. Provisional Application No. 61/038,846, filed Mar. 24, 2008, the complete disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a wrapping apparatus for wrapping a load with packaging material, and more particularly, to a wrapping apparatus having a top load packaging material dispenser. 
     BACKGROUND 
     Various packaging techniques have been used to build a load of unit products and subsequently wrap them for transportation, storage, containment and stabilization, protection and waterproofing. Products may be stacked as a load on a pallet to simplify handling of the products. The load is commonly wrapped with stretch wrap packaging material. One system uses stretch wrapping machines to stretch, dispense and wrap stretch packaging material around a load. Stretch wrapping can be performed as an inline, automated packaging technique that dispenses and wraps packaging material in a stretch condition around a load to cover and contain the load. Stretch wrapping, whether accomplished by a turntable, rotating arm, or vertical rotating ring, typically covers the four vertical sides of the load with a stretchable film such as polyethylene film. In each of these arrangements, relative rotation is provided between the load and the packaging material dispenser to wrap packaging material about the sides of the load. 
     Such a stretch wrapping apparatus performs admirably in accomplishing its intended goal of wrapping a load with a stretched web of film. However, the procedure of threading the film web through the series of rollers in the film web dispenser prior to operation of the stretch wrapping apparatus has been found to be time consuming and difficult. Conventional stretch wrapping apparatuses employ a film web dispenser having two closely spaced rollers to stretch between them a web of thermoplastic stretch film packaging material. 
     It is preferable that a stretch wrapping apparatus with pre-stretch rollers have the following features. The upstream and downstream pre-stretch rollers should be closely spaced during operation to prevent neckdown of the film web as it is being substantially stretched in the dispensing direction. Since the forces exerted on a wide web of stretch film between the pre-stretch rollers is very significant, in the order of 50 pounds of force, the frame and the mounting of the pre-stretch rollers should be required to be very sturdy. The surface of the pre-stretch rollers should be covered by the stretch film over a sufficient extent such that the stretch film does not slip on the pre-stretch rollers. The rotational inertia of the pre-stretch rollers should not be so high as to require excessively high power to vary their velocity. To accommodate these requirements, a series of idle rollers are used to support the stretch film proximate to the pre-stretch rollers. As a result, the film web follows a tortuous path around the closely spaced pre-stretch and idler rollers. The downstream pre-stretch roller has a faster surface speed than the upstream pre-stretch roller. This stretches the packaging material between the upstream and downstream pre-stretch rollers in the dispensing direction. 
     The increased numbers of rollers in the film dispenser for pre-stretch and the close spacing of such rollers with their effective interconnection for pre-stretching the film web prior to dispensing the film web on the load makes it very difficult to thread the film web through the pre-stretch portion of the film dispenser. Before operating a stretch wrapping apparatus having pre-stretch rollers, it is necessary to thread the stretch film along the tortuous path. This threading operation is difficult and time consuming since, due to the close spacing of the rollers, an operator cannot manually carry the stretch wrap packaging material between the rollers. Rather, the operator must feed the stretch wrap packaging material from one side of each roller nip with one hand and pull the stretch film from the other side of the roller nip with the other hand. This procedure is rendered considerably more difficult because of the large widths of the stretch wrap packaging material which are used commercially. Such webs generally have a width in the range of 10 to 30 inches. Other problems in threading resulted from the fact that the operator was required to place his fingers proximate to the nip of the rollers and blindly feed the film from the rear of the frame which carried the rollers, which made the threading operation difficult and more time consuming. 
     This threading problem was addressed in U.S. Pat. No. 4,747,254 to Lancaster, issued May 31, 1988, and entitled “Web Threading Device,” the entire disclosure of which is incorporated herein by reference. This earlier arrangement reduced the difficulty of threading a web along a tortuous path by using a retractable leader which ran generally parallel to the path of the film web around the rollers to lead the film along the path. However, this arrangement required the leading end of the film web to be attached to the leader and the leader to be slowly pulled through the tortuous path while rotating the pre-stretch rollers, releasing the film web from the leader and retracting the leader. 
     Pre-stretch roll carriages include at least two coated pre-stretch rollers and additional rollers which are necessary for achieving the necessary film path. The pre-stretch rollers are mounted on shafts through bearings on each end. One end has a sprocket or pulley for connecting the rollers to each other and to the drive motor. The guiding rollers are also supported at both ends. Many prior art pre-stretch roll carriages “split” either vertically or horizontally to facilitate film threading around these multiple rollers. Examples of such prior art can be seen in numerous issued patents. Virtually all prior art pre-stretch roll carriages utilize a “W” threading pattern around the pre-stretch rollers which rotate in the same direction. 
     For example, a convention pre-stretch roll carriage includes first and second upper frame portions, first and second lower frame portions, and first and second side frame portions. The first frame portions form a first side of a frame, and the second frame portions form a second side of the frame. The first and second sides of the frame are pivotable relative to one another around a hinge. This “split frame” is necessary to permit threading of the film between the first and second sides of the frames and the rollers supported therein. However, splitting or opening the frame each time a roll is loaded, or each time that threading of the film is to be carried out, can be laborious, and can lead to increases in machine downtime. 
     An attempt to simplify the threading process is exemplified in very early pre-stretch roll carriage produced by Lantech. The roll carriage utilized two pre-stretch rollers cantilevered and supported only at the top of the roll carriage, such that the bottoms of the rollers were unsupported and unconnected to any structure. This prior art device utilized an “S” threading pattern around the pre-stretch rollers, which rotated in opposite directions. This roll carriage could be threaded from the bottom without the necessity for additional idle rollers or mechanical split of the roller supports. This design was unsuccessful due to very significant problems in dealing with the forces exerted on the unsupported rollers. The forces caused deformation of the rollers and the misalignment of the gears used to maintain relative speeds of the two pre-stretch rollers. 
     One way to address deformation and misalignment problems is described in U.S. Patent Application Publication No. 2006/0254225 A1, entitled “Stretch Wrapping Apparatus Having Film Dispenser With Pre-stretch Assembly,” filed Mar. 9, 2006, and published Nov. 16, 2006, the entire disclosure of which is incorporated herein by reference. That disclosure describes a roll carriage frame including a drive plate, and a pre-stretch assembly including first and downstream pre-stretch rollers. A first end of each of the pre-stretch rollers is connected to the drive plate, while a second end of each of the pre-stretch rollers is connected to the second end of the other pre-stretch roller. The connection between the second ends helps to maintain the alignment of the pre-stretch rollers under the high forces generated during the pre-stretching of film. A cantilevered idle roller is positioned between the pre-stretch rollers. A space between the pre-stretch rollers and the idle roller forms a film path that is accessible for threading from the second ends of the pre-stretch rollers and a free end of the idle roller. 
     SUMMARY 
     In accordance with this disclosure, embodiments of a packaging material dispenser including a pre-stretch portion for pre-stretching packaging material as it is dispensed is provided. An apparatus for stretch wrapping a load including a packaging material dispenser having a pre-stretch portion for pre-stretching film as it is dispensed also is provided. 
     In accordance with this disclosure, a film dispenser is provided. The film dispenser may include an open top roll carriage having a base plate on which a film dispensing assembly, including an upstream roller and a downstream roller, is mounted. A film path for film traveling through the film-dispensing assembly may be at least partially defined by a surface of the upstream roller and a surface of the downstream roller. The film path may be accessible via the open top of the roll carriage. The film dispenser may also include a drive assembly for the upstream roller and the downstream roller mounted below the base plate. 
     In accordance with another aspect of this disclosure, a film dispenser is provided. The film dispenser may include a roll carriage having a base plate on which a film dispensing assembly is mounted, and an open top opposite the base plate. The film dispenser may also include a film path for film traveling through the film-dispensing assembly. The open top may include one or more passageways configured to receive a length of film for insertion downward into the film path. The film dispenser may also include a drive assembly for driving the film dispensing assembly. The drive assembly may be mounted below the base plate. 
     In accordance with yet another aspect of this disclosure, a method for wrapping a load is provided. The method may include inserting a length of film downward into a film path of a film dispensing assembly mounted on a base plate of a roll carriage. The method may also include providing relative rotation between the film dispensing assembly and the load. The method may also include driving the film dispensing assembly to dispense film for wrapping the load using a drive assembly mounted below the base plate. 
     Additional objects and advantages of the disclosed embodiments will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the embodiments. The objects and advantages of the embodiments may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the features claimed. 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a rotating arm of a wrapping apparatus and shows an embodiment of a packaging material dispenser mounted on the arm, according to an aspect of the disclosure; 
         FIG. 2  is an enlarged isometric view of the packaging material dispenser of  FIG. 1 ; 
         FIG. 3  is a top view of the packaging material dispenser of  FIG. 2 ; 
         FIG. 4  is a bottom view of the packaging material dispenser of  FIG. 2 ; 
         FIG. 5  is a front view of the packaging material dispenser of  FIG. 2 ; 
         FIG. 6  is a side view of the packaging material dispenser of  FIG. 2 ; 
         FIG. 7  is an isometric view of the packaging material dispenser of  FIG. 2  from a different angle; 
         FIG. 8  is an isometric view of another embodiment of a packaging material dispenser, according to an aspect of the disclosure; 
         FIG. 9  is a top view of the packaging material dispenser of  FIG. 8 ; 
         FIG. 10  is a front view of the packaging material dispenser of  FIG. 8 ; and 
         FIG. 11  is a side view of the packaging material dispenser of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the present exemplary embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     In accordance with the present disclosure, embodiments of an apparatus are provided, the apparatus being provided for wrapping a load with packaging material. The apparatus includes a packaging material dispenser having a pre-stretch assembly configured to pre-stretch the packaging material, and means for providing relative rotation between a load and the dispenser to wrap the pre-stretched packaging material around the load. The means may include a horizontal rotatable ring assembly, a vertical rotatable ring assembly, a rotatable turntable assembly, or a rotating arm assembly. The rotatable turntable assembly may include a low-profile turntable. As used herein and generally understood in the art, a low profile turntable is a rotatable turntable having a load support surface that is less than or equal to 3 inches above a floor surface supporting the turntable. 
     As embodied herein and shown in  FIGS. 1-7 , a stretch wrapping apparatus (not shown) includes a packaging material dispenser  100 . Packaging material dispenser  100  may dispense a sheet of packaging material  102  in a web form. Packaging material dispenser  100  may include a roll carriage  104 . Packaging material dispenser  100  may contain a roll  106  of packaging material  102  to be dispensed. A roll support  108  may be mounted on roll carriage  104  for this purpose. Roll support  108  may be constructed to rotatably support roll  106  as packaging material  102  unwinds, moving from roll  106  to a pre-stretch assembly  110 . 
     In one embodiment, roll support  108  may include a cylindrical member  112  extending vertically therefrom, cylindrical member  112  being sized to be received within an aperture  114  extending axially through the center of roll  106 . Roll  106  may rotate freely about cylindrical member  112  when packaging material  102  is being dispensed. Roll support  108  may be top-loaded, such that roll  106  may be loaded into packaging material dispenser  100  from above packaging material dispenser  100  by sliding roll  106  over a free end of cylindrical member  112 . Roll support  108  may support a bottom end of roll  106  once roll  106  is loaded. It is also contemplated that roll support  108  may be offset vertically from roll carriage  104 , to assist with roping a portion of packaging material  102 . 
     In an exemplary embodiment, stretch wrap packaging material is used, however, various other packaging materials such as netting, strapping, banding, or tape can be used as well. As used herein, the terms “packaging material,” “film,” “web,” and “film web” are interchangeable. 
     As embodied in  FIGS. 1-7 , packaging material dispenser  100  may include pre-stretch assembly  110 . Pre-stretch assembly  110  may include an upstream pre-stretch roller  118  and a downstream pre-stretch roller  120 . “Upstream” and “downstream,” as used in this application, are intended to define the direction of movement relative to the flow of packaging material  102  from packaging material dispenser  100 . Thus, since packaging material  102  flows from packaging material dispenser  100 , movement toward packaging material dispenser  100  and against the flow of packaging material  102  from packaging material dispenser  100  is defined as “upstream,” and movement away from packaging material dispenser  100  and with the flow of packaging material  102  from packaging material dispenser  100  is defined as “downstream.” Upstream pre-stretch roller  118  and/or downstream pre-stretch roller  120  may be connected to a power source (not shown), such as a drive motor; however, they do not need to be, and upstream pre-stretch roller  118  and/or downstream pre-stretch roller  120  therefore may be powered or unpowered. 
     Upstream pre-stretch roller  118  and downstream pre-stretch roller  120  may be the same size, and each may have, for example, an outer diameter of approximately 2.5 inches. Alternatively, upstream pre-stretch roller  118  and downstream pre-stretch roller  120  may have different sizes, as shown in  FIGS. 1-3 ,  5 , and  7 . Each of upstream pre-stretch roller  118  and downstream pre-stretch roller  120  may have a sufficient length to carry a twenty (20) inch wide web of packaging material  102  along their working lengths. In one exemplary embodiment, rollers used for conventional conveyors were used to form upstream pre-stretch roller  118  and downstream pre-stretch roller  120 . 
     As shown in  FIGS. 2 ,  5 , and  6 , upstream pre-stretch roller  118  and downstream pre-stretch roller  120  may be mounted on shafts  122  and  124 , respectively, which may be hex shafts. Bearings  126 ,  128 ,  130 , and  132 , for supporting shafts  122  and  124 , may be press-fit or welded into each end of upstream pre-stretch roller  118  and downstream pre-stretch roller  120 , and shafts  122  and  124  may be placed therethrough, such that shafts  122  and  124  may be centrally and axially mounted through the lengths of upstream pre-stretch roller  118  and downstream pre-stretch roller  120 . Shafts  122  and  124  may act as the rotational axes of upstream pre-stretch roller  118  and downstream pre-stretch roller  120 . Upstream pre-stretch roller  118  and downstream pre-stretch roller  120  may be cantilevered rollers, in that a first end of each of shafts  122  and  124  may be fixed to or supported by a base plate of roll carriage  104 , while a second end of each of shafts  122  and  123  may be unsupported, or supported by first and second supports  134  and  136 . In the latter case, shafts  122  and  123  are supported in such a way as to provide a film path for packaging material  102  to be brought into engagement with upstream pre-stretch roller  118  and downstream pre-stretch roller  120  that is freely accessible from above upstream pre-stretch roller  118  and downstream pre-stretch roller  120  despite the supports. 
     As embodied in  FIGS. 4 and 5 , a sprocket  138  may be mounted on/attached to upstream pre-stretch roller  118 , and similarly, a sprocket  140  may be mounted on/attached to downstream pre-stretch roller  120 . Sprockets  138  and  140  may be housed in a drive housing  142  below roll carriage  104 . This creates a low-profile drive design, which allows packaging material dispenser  100  to move through a wide range of vertical positions. Additionally, positioning roll carriage  104  above drive housing  142  allows roll carriage  104  to be used to prevent debris from entering into drive housing  142 . 
     Upstream pre-stretch roller  118  and downstream pre-stretch roller  120  (and sprockets  138  and  140 ) may be connected to each other through a drive belt  144 , and also to a drive motor (not shown). Drive belt  144  may include, for example, a belt, a chain, a cable, one or more gears, and/or any other suitable connection. As shown in  FIGS. 4-6 , drive belt  144  may be looped around sprockets  138  and  140 , with one side of drive belt  144  engaging sprocket  138 , and another side of drive belt  144  engaging sprocket  140 . As a result of this arrangement, upstream pre-stretch roller  118  and downstream pre-stretch roller  120  rotate in opposite directions. Sprockets  138  and  140  may be selected to produce a desired level of pre-stretch in packaging material  102 . For example, sprockets  138  and  140  may be selected such that pre-stretch assembly  110  may maintain a surface speed of downstream pre-stretch roller  120  at a speed that is faster than the speed of upstream pre-stretch roller  118 , to stretch packaging material  102  between upstream pre-stretch roller  118  and downstream pre-stretch roller  120 . It is contemplated that a clutch mechanism (not shown) may be provided to allow an operator to manually rotate upstream pre-stretch roller  118  and/or downstream pre-stretch roller  120 , when the drive motor is not running. 
     Positioning the low-profile drive components, such as drive housing  142 , sprockets  138  and  140 , and drive belt  144  below roll carriage  104  allows the top of roll carriage  104  to be open, thus making the film path freely accessible from above upstream pre-stretch roller  118  and downstream pre-strech roller  120 . Attempting to use conventional drive components to provide the open top, instead of the low-profile drive components, may not be feasible for a few reasons. 
     Impacts between bottom-mounted drive components and an object, such as, for example, the ground, a conveyor, or a machine part, may cause damage, resulting in machine downtime. Thus, a clearance must be maintained between the drive components and the object, so that impacts can be avoided. Providing that clearance requires moving the drive components vertically higher relative to a load wrapping surface to provide a clearance distance between the drive components and the object. The packaging material dispensing components on the roll carriage, being positioned above the drive components, must also be moved vertically higher by at least the sum of the clearance distance and the thickness of the drive components. The thicker the drive components, the farther away the packaging material dispensing components are from the load wrapping surface. 
     If the packaging material dispensing components are too high relative to the load wrapping surface, they may have difficulty wrapping the bottom surfaces of a load on the load wrapping surface. Even greater difficulties arise if roping assemblies are used to rope up the packaging material before it reaches the load, since roping assemblies may drive the packaging material even higher away from the load wrapping surface. While the use of drive down rollers may help drive the packaging material downward, its capacity to drive down has a limit. When that limit is exceeded, it may not be able to drive the packaging material down any further, or may fail to operate in a desired manner. 
     One way to avoid such problems associated with bottom-mounted drive components is by eliminating mechanical drive components, so that packaging material dispensing rollers mounted on the roll carriage are driven by separate motors controlled by a microprocessor unit. Such an arrangement, however, would increase the complexity and cost of a system. 
     The overall vertical thickness of low-profile drive components, such as drive housing  142 , sprockets  138  and  140 , and drive belt  144 , allows those components to be mounted below roll carriage  104  (enabling the open top), while avoiding the above-described drawbacks. This is because the vertical thickness of the low-profile drive components is less than that of conventional components. Thus, packaging material  102  can be dispensed at a height closer to the bottom surfaces of a load than would be possible using conventional components. In addition, offsetting the height of roll support  108  relative to roll carriage  104  helps to compensate for the vertical thicknesses of drive housing  142 , sprockets  138  and  140 , and drive belt  144 . 
     As embodied in  FIGS. 1-3  and  5 - 7 , first and second supports  134  and  136  may extend from roll carriage  104 , or from any other suitable structure that is fixed relative to roll carriage  104 . In one embodiment, first support  134  may include a bent plate or bracket with a fixed end coupled to a surface on or near an upper portion of roll carriage  104 , and a free end configured to receive shaft  122 ; and second support  136  may include a vertical support  146  coupled to and extending from the base plate of roll carriage  104 , and a horizontal support  148  having a fixed end coupled to vertical support  146 . A free end of horizontal support  148  may be configured to receive shaft  124 . Mounting the first ends of shafts  122  and  124  to roll carriage  104 , and providing first and second supports  134  and  136  to support the second ends of shafts  122  and  124 , may help to ensure that upstream pre-stretch roller  118  and downstream pre-stretch roller  120  maintain their alignment even under high forces that may be generated during pre-stretching of packaging material  102 . This design may also permit easy threading of packaging material fully around upstream pre-stretch roller  118 , downstream pre-stretch roller  120 , an upstream idle roller  150 , a first downstream idle roller  152 , a second downstream idle roller  154 , and a third downstream idle roller. 
     Upstream idle roller  150 , first downstream idle roller  152 , second downstream idle roller  154 , and third downstream idle roller, may each be cantilevered from the base plate of roll carriage  104 , as shown in  FIGS. 1-7 . Any or all of upstream idle roller  150 , first downstream idle roller  152 , second downstream idle roller  154 , and third downstream idle roller  156  may be the same diameter as or smaller in diameter than upstream pre-stretch roller  118  or downstream pre-stretch roller  120 . Upstream idle roller  150 , first downstream idle roller  152 , second downstream idle roller  154 , and third downstream idle roller  156  may be coated or uncoated. As with upstream pre-stretch roller  118  and downstream pre-stretch roller  120 , upstream idle roller  150 , first downstream idle roller  152 , second downstream idle roller  154 , and third downstream idle roller  156 , should have a sufficient length to carry a twenty (20) inch wide web of packaging material  102  along their working lengths. It is contemplated that upstream idle roller  150  and first downstream idle roller  152  may be cantilevered rollers, in that upstream idle roller  150  and first downstream idle roller  152  may be supported at a first lower end by roll carriage  104 , but may not be supported at a second upper end, opposite the first lower end, by additional support structure. This arrangement allows packaging material  102  to be easily threaded through pre-stretch assembly  110  from the open top of roll carriage  104 . Second downstream idle roller  154  and third downstream idle roller  156  may be supported on one or both ends by other structures in packaging material dispenser  100 . 
     Third downstream idle roller  156  may be selectively tiltable from the vertical position shown in  FIGS. 1-5  and  7 , to a tilted position, such that an angle is formed between the longitudinal axis of third downstream idle roller  156  in the vertical position, and the longitudinal axis of third downstream idle roller  156  in the tilted position. Third downstream idle roller  156  may be actuated into a tilted position, thus driving down packaging material  102  from a first elevation to a second elevation, lower than the first elevation, before applying packaging material  102  to the load being wrapped. By driving down packaging material  102 , third downstream idle roller  156  may position at least a portion of packaging material  102  at an elevation lower than the bottom of a load and the top of a pallet supporting the load, thus helping to secure the load to the pallet. Thus, packaging material dispenser  100  does not have travel as low vertically to secure the load to the pallet, which may be beneficial, since drive housing  142  should be kept above the ground or any other support surfaces. One example of how third downstream idle roller  156  can be actuated into the tilted position can be found in U.S. Patent Application Publication No. 2007/0209324 A1, entitled “Method and Apparatus for Securing a Load to a Pallet With a Roped Film Web,” filed Feb. 23, 2007, and published Sep. 13, 2007, the entire disclosure of which is incorporated herein by reference. 
     A film path is defined by and between the surfaces of upstream pre-stretch roller  118 , downstream pre-stretch roller  120 , upstream idle roller  150 , first downstream idle roller  152 , second downstream idle roller  154 , and third downstream idle roller  156 . The film path is easily accessible via the top of pre-stretch assembly  110 , as shown in  FIGS. 1-3  and  7 . A rope of packaging material  102  may be pulled from roll  106 , around upstream idle roller  150 , between upstream idle roller  150  and upstream pre-stretch roller  118 , around upstream pre-stretch roller  118 , between upstream pre-stretch roller  118  and downstream pre-stretch roller  120 , around downstream pre-stretch roller  120 , in between downstream pre-stretch roller  120  and first downstream idle roller  152 , around first downstream idle roller  152 , between first downstream idle roller  152  and second downstream idle roller  154 , over second downstream idle roller  154 , over third downstream idle roller  156 , and to the load. As shown in  FIG. 3 , the portion of the film path between upstream idle roller  150  and first downstream idle roller  152  has an S-configuration. It is contemplated that at least one of first, second, and third downstream idle rollers  152 ,  154 , and  156 , may be mounted as a “dancer” and may be used to sense any slack in packaging material  102  caused by a change in the size or shape of the load being wrapped, or a break in packaging material  102 . 
     As embodied in  FIGS. 1-7 , packaging material dispenser  100  may also include an upstream roping assembly  158 , and a downstream roping assembly  160 . Upstream roping assembly  158 , assisted by the offset between roll carriage  104  and roll support  108 , may form a rope from bottom portion of packaging material  102  before packaging material  102  enters pre-stretch assembly  110 . Downstream roping assembly  160  may create another rope, or reinforce the rope, after packaging material  102  leaves pre-stretch assembly  110 . Thus, it should be apparent that by using the offset between roll carriage  104  and roll support  108 , and upstream roping assembly  158 , more of packaging material  102  may be formed into the rope than if the offset and upstream roping assembly  158  were not used. Additionally, if the offset was not used, and roll support  108  was level with the base plate of roll carriage  104 , then roping up with upstream roping assembly  158  would drive the bottommost edge of packaging material  102  farther upward, thus requiring third downstream idle roller  156  to drive packaging material  102  farther downward in response to ensure that packaging material  102  can be wrapped around the bottom of the load and/or the top of a pallet supporting the load. 
     Roping may be carried out at any time during a wrapping cycle, including near the end of a wrapping cycle, to secure the bottom of the load to a pallet (not shown), or during an intermediate portion of a wrapping cycle, to wrap a roped web of packaging material  102  around the sides of the load. A rope may include a portion of packaging material  102  that is concentrated in a tightly compacted, and preferably somewhat round, shape. A rope may be a conventional rope of packaging material, which is gathered, compacted or compressed; or may be a rolled cable of packaging material  102 . A more detailed explanation of the general structure, operation, and benefits of various roping assemblies can be found in U.S. Patent Application Publication No. 2007/0209324 A1, entitled “Method and Apparatus for Securing a Load to a Pallet With a Roped Film Web,” filed Feb. 23, 2007, and published Sep. 13, 2007, the entire disclosure of which is incorporated herein by reference. 
     Downstream roping assembly  160  may be placed immediately downstream of second downstream idle roller  154 . This positioning of downstream roping assembly  160  creates a rolled cable of packaging material  102  that is capable of maintaining its structural integrity as a rope structure during and after wrapping of a load. Downstream roping assembly  160  and second downstream idle roller  154  may form a “rolled cable rolling means” for rolling a portion of packaging material  102  into a rolled cable. The rolled cable rolling means rolls an outer edge of packaging material  102  inward upon itself and toward the center of packaging material  102 . The film is rolled upon itself to form a tightly rolled cable of film, or a high tensile rolled cable of film along an edge of the packaging material  102 . Further, by placing downstream roping assembly  160  immediately downstream of second downstream idle roller  154 , the rolling of packaging material  102  into a rolled cable may begin at a point upstream from second downstream idle roller  154 . Additionally, downstream roping assembly  160  may serve to elevate the bottom edge of packaging material  102  before it is driven down by the tilting of third downstream idle roller  156 , thus helping to prevent packaging material  102  from sliding off the bottom of third downstream idle roller  156 , and causing other malfunctions. A more detailed explanation of the rolled cable rolling means can be found in U.S. Patent Publication No. 2005/0044812, entitled “Method and Apparatus for Securing a Load to a Pallet With a Roped Film Web,” filed Jan. 30, 2004, and published Mar. 3, 2005, the entire disclosure of which is incorporated herein by reference. It is contemplated that second downstream idle roller  154  may be coated to assist with roping. 
     According to one aspect of the disclosure, means for providing relative rotation between a load and packaging material dispenser  100  may be provided. The means for providing relative rotation may include, for example, a rotatable turntable (not shown). In such an embodiment, packaging material dispenser  100  may be mounted on a stationary mast (not shown) upon which packaging material dispenser  100  can be vertically driven and positioned to dispense packaging material  102  to spirally wrap the load, as the load rotates on the turntable. In such an embodiment, the low-profile design of drive housing  142 , and the elements contained therein, provides packaging material dispenser  100  with the ability to wrap a bottom portion of the load, including a top portion of a pallet if the load is supported by a pallet, while remaining high enough above the turntable and/or a floor surface (not shown) supporting the turntable, to avoid interference with/from the turntable and/or the floor surface. 
     Alternatively, packaging material dispenser  100  may be vertically driven on a rotating arm  116 , shown in  FIG. 1 , to dispense packaging material  102  spirally about the load, as rotating arm  116  rotates about the load, and packaging material dispenser  100  moves vertically along rotating arm  116 . It is also contemplated that packaging material dispenser  100  may be mounted on horizontal wrapping ring (not shown) to dispense packaging material  102  spirally about the load, as packaging material dispenser  100  rotates with the wrapping ring relative to the load. In the rotating arm and horizontal wrapping ring embodiments, a conveyor (not shown) may convey the load into and out of a wrapping area defined by the path of packaging material dispenser  100  around the load. In such embodiments, during wrapping, packaging material dispenser  100  must pass over the conveyor while rotating around the load. The low-profile design of drive housing  142 , and the elements contained therein, as well as the offset between roll support  108  and roll carriage  104 , provide packaging material dispenser  100  with the ability to wrap a bottom portion of the load, including a top portion of a pallet if the load is supported by a pallet, while remaining high enough above the conveyor to avoid interference with/from the conveyor. 
     As embodied herein and shown in  FIGS. 8-11 , a stretch wrapping apparatus (not shown) includes a packaging material dispenser  200 . Packaging material dispenser  200  may dispense a sheet of packaging material  202  (see  FIG. 10 ) in a web form. Packaging material dispenser  200  may include a roll carriage  204 . Packaging material dispenser  200  may contain a roll  206  (see  FIG. 10 ) of packaging material  202  to be dispensed. A roll support  208  may be mounted on roll carriage  204  for this purpose. Roll support  208  may be constructed to rotatably support roll  206  as packaging material  202  unwinds, moving from roll  206  to a pre-stretch assembly  210 . 
     In one embodiment, roll support  208  may include a cylindrical member  212  extending vertically therefrom, cylindrical member  212  being sized to be received within an aperture  214  extending axially through the center of roll  206 . Roll  206  may rotate freely about cylindrical member  212  when packaging material  202  is being dispensed. Roll support  208  may be top-loaded, such that roll  206  may be loaded into packaging material dispenser  200  from above packaging material dispenser  200  by sliding roll  206  over a free end of cylindrical member  212 . Roll support  208  may support a bottom end of roll  206  once roll  206  is loaded. 
     As embodied in  FIGS. 8-11 , packaging material dispenser  200  may include pre-stretch assembly  210 . Pre-stretch assembly  210  may include an upstream pre-stretch roller  216  and a downstream pre-stretch roller  218 , that are in many ways similar to upstream pre-stretch roller  118  and downstream pre-stretch roller  120  of packaging material dispenser  100 . However, upstream pre-stretch roller  216  and downstream pre-stretch roller  218  may be the same size, and each may have, for example, an outer diameter of approximately 2.5 inches. 
     Upstream pre-stretch roller  216  and downstream pre-stretch roller  218  may be mounted on shafts  220  and  222 . Shafts  220  and  222  are similar to shafts  122  and  124 , described above. In packaging material dispenser  200 , upstream pre-stretch roller  216  and downstream pre-stretch roller  218  may be cantilevered rollers, in that a first end of each of shafts  220  and  222  may be fixed to or supported by a base plate of roll carriage  204 , while a second end of each of shafts  220  and  222  may be unsupported. It is also contemplated that the second end of each of shafts  220  and  222  may be supported by a separate support member  232  coupled to an upper portion of roll carriage  204 . In that case, support member  232  may support shafts  220  and  222  in such a way as to provide a film path for bringing packaging material  202  into contact with upstream pre-stretch roller  215  and downstream pre-stretch roller  218 , freely accessible from above upstream pre-stretch roller  215  and downstream pre-stretch roller  218  despite the supports. 
     As embodied in  FIGS. 8 and 10 , a sprocket  234  may be mounted on/attached to upstream pre-stretch roller  216 , and similarly, a sprocket  236  may be mounted on/attached to downstream pre-stretch roller  218 . Sprockets  234  and  236  may be housed in a drive housing  238  below roll carriage  204 . This creates a low-profile drive design, and prevents debris from entering into drive housing  238 . 
     Sprockets  234  and  236  may be connected to each other through a drive belt  240 , and also to a drive motor (not shown). Drive belt  240  may include, for example, a chain, a belt, a cable, one or more gears, and/or any other suitable connection. As shown in  FIGS. 8 ,  10 , and  11 , drive belt  240  may be threaded around sprockets  234  and  236 , with a first side of drive belt  240  engaging both of sprockets  234  and  236 . This arrangement causes upstream pre-stretch roller  216  and downstream pre-stretch roller  218  may rotate in the same direction. Sprockets  234  and  236  may be selected based on the same criteria as sprockets  138  and  140 . It is contemplated that a clutch mechanism (not shown) may be provided to allow an operator to manually rotate upstream pre-stretch roller  216  and/or downstream pre-stretch roller  218 , when the drive motor is not running. 
     As embodied in  FIGS. 8-11 , a support member  232  may extend from the upper portion of roll carriage  204 , or any other suitable structure fixed relative to roll carriage  204 . In one embodiment, support member  232  may include a bent plate or bracket with a base member  242 , fixed relative to roll carriage  204 , that joins a first support  244  to a second support  246 . A gap may exist between first support  244  and second support  246 , allowing for threading of packaging material  202  from above upstream pre-stretch roller  216  and downstream pre-stretch roller  218 , as is evident in  FIG. 9 . First support  244  may be configured to receive shaft  220 . Second support  246  may be configured to receive shaft  222 . Mounting the first ends of shafts  220  and  222  to roll carriage  204 , and providing support member  232  to support the second ends of shafts  220  and  222 , may help to ensure that upstream pre-stretch roller  216  and downstream pre-stretch roller  218  maintain their alignment even under high forces that may be generated during pre-stretching of packaging material  202 . This design may also permit easy threading of packaging material fully around upstream pre-stretch roller  216 , downstream pre-stretch roller  218 , an upstream idle roller  248 , an intermediate idle roller  250 , and a downstream idle roller  252 . 
     Upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252 , may each be cantilevered from roll carriage  204 , as shown in  FIGS. 8-11 . Any or all of upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252 , may be the same diameter as or smaller in diameter than upstream pre-stretch roller  216  or downstream pre-stretch roller  218 . Upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252  may be coated or uncoated. As with upstream pre-stretch roller  216  and downstream pre-stretch roller  218 , upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252 , should have a sufficient length to carry a twenty (20) inch wide web of packaging material  202  along their working lengths. It is contemplated that upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252  may be cantilevered rollers, in that upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252  may be supported at a first lower end by roll carriage  204 , but may not be supported at a second upper end, opposite the first lower end, by additional support structure. This arrangement allows packaging material  202  to be easily threaded through pre-stretch assembly  210  from the open top of roll carriage  204 . Further, support member  232 , being C-shaped, as shown in  FIGS. 8 and 9 , will not obstruct packaging material  202  during threading of pre-stretch assembly  210  from the open top of roll carriage  204 . 
     A film path is defined by and between the surfaces of upstream pre-stretch roller  216 , downstream pre-stretch roller  218 , upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252 . The film path is easily accessible via the top of pre-stretch assembly  210 , as shown in  FIGS. 8 and 9 . A rope of packaging material  202  may be pulled from roll  206 , around upstream idle roller  248 , between upstream idle roller  248  and upstream pre-stretch roller  216 , around upstream pre-stretch roller  216 , between upstream pre-stretch roller  216  and intermediate idle roller  250 , around intermediate idle roller  250 , between intermediate idle roller  250  and downstream pre-stretch roller  218 , around downstream pre-stretch roller  218 , in between downstream pre-stretch roller  218  and downstream idle roller  252 , downstream idle roller  252 , and to the load. It should be evident from  FIG. 9  that the portion of the film path between upstream idle roller  248  and downstream idle roller  252  has a W-configuration. It is contemplated that at least one of upstream idle roller  248 , intermediate idle roller  250 , and downstream idle roller  252 , may be mounted as a “dancer” and may be used to sense any slack in packaging material  202  caused by a change in the size or shape of the load being wrapped, or a break in packaging material  202 . 
     According to one aspect of this disclosure, intermediate idle roller  250  may include an idle roller hingedly connected to roll carriage  204  and/or support member  232 . As shown in  FIGS. 8-10 , intermediate idle roller  250  may be mounted in between upstream pre-stretch roller  216  and downstream pre-stretch roller  218 , and may be movable outward, away from one or both of upstream pre-stretch roller  216  and downstream pre-stretch roller  218 . Movement of intermediate idle roller  250  away from upstream pre-stretch roller  216  and/or downstream pre-stretch roller  218  provides access to the space between upstream pre-stretch roller  216  and downstream pre-stretch roller  218 , to permit threading of packaging material  202  around upstream pre-stretch roller  216  and downstream pre-stretch roller  218 . 
     As shown in  FIG. 9 , intermediate idle roller  250  may be positioned between upstream pre-stretch roller  216  and downstream pre-stretch roller  218 , abutting one of upstream pre-stretch roller  216  and downstream pre-stretch roller  218 , and spaced from the other of upstream pre-stretch roller  216  and downstream pre-stretch roller  218 . Preferably intermediate idle roller  250  may be aligned to provide a pinching action on upstream pre-stretch roller  216 , as shown in  FIG. 9 , and as disclosed in U.S. Pat. No. 5,414,979 to Moore et al., issued May 16, 2995, and entitled “Stretch Wrapping Apparatus,” the entire disclosure of which is incorporated herein by reference. This may reduce the amount of unsupported packaging material  202  by 100%. Reducing the amount of unsupported packaging material  202 , reduces the amount of neckdown in the width dimension of packaging material  202 . This generates a greater area of stretch of the film. In this embodiment, the inventors have noticed an almost complete elimination of film slippage on upstream pre-stretch roller  216 . 
     Intermediate idle roller  250  may be biased against the pre-stretch roller which it is abutting, for example, against upstream pre-stretch roller  216 . The hinged mounting of intermediate idle roller  250  permits packaging material  202  to bias intermediate idle roller  250  against upstream pre-stretch roller  216 . This is achieved through the force vector resulting from the geometry of the mountings and force application by packaging material  202 . Alternatively, the biasing may be achieved through the use of a spring or similar element (not shown). 
     The result of this arrangement is that intermediate idle roller  250  effectively acts like a pinch roller or press roller in relation to upstream pre-stretch roller  216 . As a pinch roller or press roller, intermediate idle roller  250  effectively acts as an extension of upstream pre-stretch roller  216  by offering increased surface for traction to packaging material  202 . In doing so, intermediate idle roller  250  pinches the film between itself and upstream pre-stretch roller  216  to offer greater traction. Increased traction of upstream pre-stretch roller  216  reduces the damage to packaging material  202  by decreasing the abrasion of packaging material  202 . While intermediate idle roller  250  is shown abutting upstream pre-stretch roller  216 , it is possible for intermediate idle roller  250  to instead abut downstream pre-stretch roller  218 , or may abut neither of upstream pre-stretch roller  216  and downstream pre-stretch roller  218 . 
     Packaging material dispenser  200  may also include an upstream roping assembly (not shown), and/or a downstream roping assembly (not shown), similar to those described with respect to packaging material dispenser  100 . 
     According to one aspect of the disclosure, means for providing relative rotation between a load and packaging material dispenser  200  may be provided. The means for providing relative rotation may include, for example, a rotatable turntable (not shown). In such an embodiment, packaging material dispenser  200  may be mounted on a stationary mast (not shown) upon which packaging material dispenser  200  can be vertically driven and positioned to dispense packaging material  202  to spirally wrap the load as the load rotates on the turntable. In such an embodiment, the low-profile design of drive housing  238 , and the elements contained therein, provides packaging material dispenser  200  with the ability to wrap a bottom portion of the load, including a top portion of a pallet if the load is supported by a pallet, while remaining high enough above the turntable and/or a floor surface (not shown) supporting the turntable, to avoid interference with/from the turntable and/or the floor surface. 
     Alternatively, packaging material dispenser  200  may be vertically driven on a rotating arm (not shown), to dispense packaging material  202  spirally about the load, as the rotating arm rotates about the load, and packaging material dispenser  200  moves vertically along the rotating arm. It is also contemplated that packaging material dispenser  200  may be mounted on a horizontal wrapping ring (not shown) to dispense packaging material  202  spirally about the load, as packaging material dispenser  200  rotates with the wrapping ring relative to the load. In the rotating arm and horizontal wrapping ring embodiments, a conveyor (not shown) may convey the load into and out of a wrapping area defined by the path of packaging material dispenser  200  around the load. In such embodiments, during wrapping, packaging material dispenser  200  must pass over the conveyor while rotating around the load. The low-profile design of drive housing  238 , and the elements contained therein, provides packaging material dispenser  200  with the ability to wrap a bottom portion of the load, including a top portion of a pallet if the load is supported by a pallet, while remaining high enough above the conveyor to avoid interference with/from the conveyor. 
     Several benefits may be associated with packaging material dispensers  100  and  200 . Roll carriages  104  and  204  provide for fast and reliable loading of rolls  106  and  206  during roll changes, and for fast and reliable loading (threading) of packaging material  102  and  202  through pre-stretch assemblies  110  and  210 . One of the reasons that loading is faster and more reliable is because packaging material dispensers  100  and  200  do not have doors that must be opened to load rolls  106  and  206  and to thread packaging material  102  and  202 . Rolls  106  and  206  may be loaded from the open tops of roll carriages  104  and  204 , and packaging material  102  and  202  may be threaded through the film path from the open tops. Also, less technique is required from an operator to load rolls  106  and  206 , and packaging material  102  and  202 , from the open tops as compared to conventional roll carriage assemblies. Another added benefit of loading from the open tops is that loading may be accomplished with packaging material dispensers  100  and  200  occupying a vertically low position, such as the usual position occupied at the end of a wrapping cycle after a bottom portion of the load has been wrapped. In conventional assemblies, the roll carriage usually must be raised from the vertically lower position to a height that is ergonomically convenient for the operator, so that the operator can to load and thread a new roll of packaging material. This raising can be time consuming and inconvenient. Yet another benefit is that the open top arrangements allow for threading of roped packaging material, which is stronger and more resistant to breakage than a non-roped web of packaging material. Additionally, the open top S-configuration and W-configuration require fewer parts than conventional assemblies, which may produce cost savings, and may reduce the weight of packaging material dispensers  100  and  200 . Further, the parts that are required are less complex, and thus, less costly. 
     Additionally, roping packaging material  102  may provide packaging material  102  with extra strength, thus helping to prevent packaging material breaks. Further, by roping packaging material  102 , if for some reason packaging material  102  is damaged (e.g., torn or punctured), the rope will help to carry the damaged portions. That is, the strength of the rope allows it to resist breaking, even when the non-roped portion of packaging material  102  is damaged. Thus, damaged portions of packaging material  102  can be carried through by the rope and applied to the load, which prevents the downtime associated with re-loading packaging material dispenser  100  after a complete break occurs. 
     Further, by driving down packaging material  102 , third downstream idle roller  156  may help to secure the load to the pallet, while maintaining space between drive housing  142  and the ground or other low support surfaces. Upstream from where the driving down occurs, downstream roping assembly  160  may rope up packaging material  102  to prevent packaging material  102  from sliding off the bottom of third downstream idle roller  156  during the driving down. 
     One method for loading packaging material  102  in packaging material dispenser  100  will now be described. With packaging material dispenser  100  in a vertically low position, such as that occupied at the end of a previous wrapping cycle, an operator may begin loading packaging material dispenser  100  by sliding roll  106  onto cylindrical member  112  of roll support  108  from above cylindrical member  112 . The operator may grasp a leading end of packaging material  102  from roll  106 . The operator may pull the leading end to produce a length of film. The length of film may have a distal portion near the leading end, a proximal portion near roll  106 , and an intermediate portion between the distal portion and the proximal portion. It is also contemplated that the operator may form at least a portion of the length of film into a rope. 
     In order to thread the length of film through pre-stretch assembly  110 , the operator may bring the proximal portion into contact with a surface of upstream idle roller  150  from above upstream idle roller  150  or from its side. The operator may bring a part of the intermediate portion into contact with a surface of upstream pre-stretch roller  118  from a location proximate a top portion of upstream pre-stretch roller  118 . The operator may bring another part of the intermediate portion into contact with a surface of downstream pre-stretch roller  120  from above downstream pre-stretch roller  120 , or from its side. The operator may bring a part of the distal portion into contact with a surface of first downstream idle roller  152  from a location proximate a top of first downstream idle roller  152 , and then bring other parts of the distal portion into contact with second downstream idle roller  154  and third downstream idle roller  156 , before attaching the leading end to a clamping assembly (not shown) and/or to a load to be wrapped (not shown). During loading, all of the rollers coming into contact with the length of film may remain substantially static. 
     Additionally or alternatively, the method for loading may include grasping a leading end portion of packaging material  102 , and, while grasping the leading end portion, bringing the leading end portion into contact with a surface of upstream idle roller  150 , and then into contact with a surface of upstream pre-stretch roller  118 , then into contact with a surface of downstream pre-stretch roller  120 , then into contact with a surface of first downstream idle roller  152 , and then into contact with second downstream idle roller  154  and third downstream idle roller  156 , before attaching the leading end to a clamping assembly (not shown) and/or to a load to be wrapped (not shown). 
     After clamping, the operator may ungrasp the leading end portion. In this embodiment of the method, the operator may be required to continually pull the leading end portion around one or more of the contacting rollers as the leading end portion is threaded through pre-stretch assembly  110 . Thus, in this embodiment, it may be necessary to provide upstream pre-stretch roller  118  and downstream pre-stretch roller  120  with a clutch mechanism that allows upstream pre-stretch roller  118  and downstream pre-stretch roller  120  to be rotated manually as the leading end portion is pulled by the operator. 
     With the leading end being clamped by the clamping assembly, relative rotation may be provided between the load being wrapped and packaging material dispenser  100 , causing packaging material  102  to be wrapped about the load. Packaging material dispenser  100  may travel vertically from a bottom portion of the load to a top portion of the load, and then back down to the bottom portion, while the relative rotation is being provided, to spirally wrap packaging material  102  about the load. During any portion of the wrapping cycle, downstream roping assembly  160  may be actuated to engage a bottom edge of packaging material  102  to form a bottom portion of packaging material  102  into a rope. Packaging material  102 , including the roped portion, may be applied to the load being wrapped. Also, near the end of the wrapping cycle, third downstream idler roller  156  may be actuated into its tilted position to drive packaging material  102  downward, to secure a bottom portion of the load to a pallet supporting the load. 
     One method for loading packaging material  202  in packaging material dispenser  200  will now be described. With packaging material dispenser  200  in a vertically low position, such as that occupied at the end of a previous wrapping cycle, an operator may begin loading packaging material dispenser  200  by sliding roll  206  onto cylindrical member  212  of roll support  208  from above cylindrical member  212 . The operator may grasp a leading end of packaging material  202  from roll  206 . The operator may pull the leading end to produce a length of film. The length of film may have a distal portion near the leading end, a proximal portion near roll  206 , and an intermediate portion between the distal portion and the proximal portion. It is also contemplated that the operator may form at least a portion of the length of film into a rope. 
     In order to thread the length of film through pre-stretch assembly  210 , the operator may bring the proximal portion into contact with a surface of upstream idle roller  248  from above upstream idle roller  248 . The operator may bring a part of the intermediate portion into contact with a surface of upstream pre-stretch roller  216  from a location proximate a top portion of upstream pre-stretch roller  216 , or from its side. The operator may bring another part of the intermediate portion into contact with a surface of intermediate idle roller  250  from above intermediate idle roller  250 . The operator may bring yet another part of the intermediate portion into contact with a surface of downstream pre-stretch roller  218  from above downstream pre-stretch roller  218 , or from its side. The operator may bring a part of the distal portion into contact with a surface of downstream idle roller  252  from a location proximate a top of downstream idle roller  252 , before attaching the leading end to a clamping assembly (not shown) and/or to a load to be wrapped (not shown). During loading, all of the rollers coming into contact with the length of film may remain substantially static. 
     Additionally or alternatively, the method for loading may include grasping a leading end portion of packaging material  202 , and, while grasping the leading end portion, bringing the leading end portion into contact with the surfaces of upstream idle roller  248 , upstream pre-stretch roller  216 , intermediate idle roller  250 , downstream pre-stretch roller  218 , and downstream idle roller  252 , before attaching the leading end to a clamping assembly (not shown) and/or to a load to be wrapped (not shown). 
     With the leading end being clamped by the clamping assembly, relative rotation may be provided between the load being wrapped and packaging material dispenser  200 , causing packaging material  202  to be wrapped about the load. Packaging material dispenser  200  may travel vertically from a bottom portion of the load to a top portion of the load, and then back down to the bottom portion, while the relative rotation is being provided, to spirally wrap packaging material  202  about the load. 
     Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.