LOAD SHAPING OF STRETCH WRAPPED PALLETIZED LOADS

Abstract

Compressive forces are applied across opposing sides of a palletized load either before, after, or during stretch wrapping to generate a load having a desirable shape profile once wrapped. The compressive forces may be used, for example, in some instances to overcompress a load in one or more lateral directions beyond desired finished dimensions, such that once the load is thereafter allowed to recover or relax, the load assumes the desired finished dimensions.

Claims

1. A method of generating a wrapped load having a first length in a first lateral direction, the method comprising: receiving a load that is unwrapped and that has a second length in the first lateral direction that is larger than the first length in the first lateral direction; applying a compressive force to opposing sides of the load along the first lateral direction to compress the load to a third length in the first lateral direction that is smaller than the first length in the first lateral direction; wrapping the load with packaging material using a load wrapping apparatus by generating relative rotation between a packaging material dispenser and the load about an axis of rotation; and allowing the load to recover in the first lateral direction such that the load has the first length in the first lateral direction after the load has been wrapped with packaging material.

2. The method of claim 1, wherein the load is supported by a pallet, and the first length is substantially equal to a length of the pallet in the first lateral direction.

3. The method of claim 1, wherein applying the compressive force is performed prior to wrapping the load.

4. The method of claim 1, wherein applying the compressive force is performed after wrapping the load.

5. The method of claim 1, wherein applying the compressive force is performed while wrapping the load.

6. The method of claim 5, wherein applying the compressive force to the opposing sides of the load includes positioning opposing press members adjacent the opposing sides of the load, wherein wrapping the load is performed while the opposing press members are positioned adjacent the opposing sides of the load such that packaging material is wrapped over at least a portion of the opposing press members, and wherein the method further comprises withdrawing the opposing press members after wrapping the load.

7. The method of claim 6, wherein withdrawing the opposing press members further comprises engaging the load to restrict lifting of the load while withdrawing the opposing press members.

8. The method of claim 1, wherein applying the compressive force is performed while the load is supported by a conveyor.

9. The method of claim 1, wherein the opposing sides includes first and second sides, and applying the compressive force is performed using first and second opposing press members respectively contacting the first and second sides.

10. The method of claim 9, wherein the first and second press members respectively contact the first and second sides substantially across at least about 50 percent of the second length.

11. The method of claim 9, wherein the first and second sides have respective first and second heights, and wherein the first and second press members respectively contact the first and second sides across at least about 50 percent of the first and second heights.

12. The method of claim 9, wherein the first and second press members respectively contact the first and second sides proximate midpoints of the first and second sides.

13. The method of claim 9, wherein the first and second press members respectively include first and second planar surfaces that respectively contact the first and second sides.

14. The method of claim 9, wherein applying the compressive force includes moving the first and second press members a predetermined distance.

15. The method of claim 9, wherein applying the compressive force includes moving the first and second press members to apply a predetermined force to the load.

16. The method of claim 9, further comprising determining at least one of a distance to move the first and second press members and a force to apply with the first and second press members based on the first and second lengths.

17. The method of claim 1, wherein the compressive force is a first compressive force and the opposing sides are a first set of opposing sides of the load, the method further comprising generating the wrapped load to have a first width in a second lateral direction that is substantially perpendicular to the first lateral direction, wherein the load is received with a second width in the second lateral direction that is larger than the first width in the second lateral direction, and wherein generating the wrapped load to have the first width in the second lateral direction includes: applying a second compressive force to a second set of opposing sides of the load along the second lateral direction to compress the load to a third width in the second lateral direction that is smaller than the first width in the second lateral direction; and allowing the load to recover in the second lateral direction such that the load has the first width in the second lateral direction after the load has been wrapped with packaging material.

18. The method of claim 17, wherein applying the first compressive force and applying the second compressive force are performed concurrently.

19. The method of claim 17, wherein applying the first compressive force and applying the second compressive force are performed sequentially.

20. The method of claim 17, wherein the first set of opposing sides includes first and second sides and the second set of opposing sides includes third and fourth sides, wherein applying the first and second compressive forces is performed using first, second, third, and fourth press members respectively contacting the first, second, third, and fourth sides.

21. The method of claim 20, wherein the first, second, third, and fourth press members are supported by a support structure providing movement of the first and second press members substantially along the first lateral direction and movement of the third and fourth press members substantially along the second lateral direction.

22. The method of claim 21, wherein applying the first and second compressive forces is performed using at least one drive operably coupled to the first, second, third, and fourth press members to move the first and second press members along the first lateral direction to apply the first compressive force to the first set of opposing sides and to move the third and fourth press members along the second lateral direction to apply the second compressive force to the second set of opposing sides.

23. The method of claim 22, wherein the at least one drive includes at least one screw drive, at least one chain drive, at least one belt drive, at least one electric motor, at least one electric drive, at least one pneumatic drive, or at least one hydraulic actuator.

24. The method of claim 20, wherein the first, second, third, and fourth press members are configured to apply the first and second compressive forces while the load is disposed on a conveyor, wherein the third and fourth press members each comprise at least one door movable between an open position and a closed position, the method further comprising: prior to applying the first and second compressive forces, moving the at least one door of the third press member to the open position when conveying the load along the conveyor to position the load between the first and second press members; and after applying the first and second compressive forces, moving the at least one door of the fourth press member to the open position when conveying the load along the conveyor downstream of the first and second press members.

25. The method of claim 20, further comprising: prior to applying the second compressive forces, moving the first, second, third, and fourth press members in a substantially vertical direction to respectively position the first, second, third, and fourth press members adjacent to the first, second, third, and fourth sides; and after applying the first and second compressive forces, moving the first, second, third, and fourth press members in an opposite substantially vertical direction.

26. The method of claim 20, wherein the first and third sides of the load extend along a first corner of the load, and the first and third press members include a plurality of interleaved fingers extending laterally to constrain the first corner of the load when applying the first and second compressive forces.

27. The method of claim 20, wherein the first and third sides of the load extend along a first corner of the load, and the first and third press members are movably coupled to a floating corner member that extends along the first corner to constrain the first corner of the load when applying the first and second compressive forces.

28. The method of claim 1, wherein wrapping the load is performed after applying the compressive force and using a wrap profile that applies a first containment force to the load based upon compressed dimensions of the load during wrapping such that a second containment force that is higher than the first containment force is applied to the load after recovery of the load after wrapping.

29. The method of claim 1, wherein wrapping the load is performed while applying the compressive force and using a wrap profile that applies a first containment force to the load based upon compressed dimensions of the load during wrapping such that a second containment force that is higher than the first containment force is applied to the load after recovery of the load after wrapping.

30. The method of claim 1, wherein wrapping the load is performed prior to applying the compressive force and using a wrap profile that applies a first containment force to the load based upon uncompressed dimensions of the load during wrapping such that a second containment force that is lower than the first containment force is applied to the load after recovery of the load after applying the compressive force.

31. A method of generating a wrapped load having a first length in a first lateral direction and a first width in a second lateral direction that is substantially perpendicular to the first lateral direction, the method comprising: receiving a load that is unwrapped and that has a second length in the first lateral direction and a second width in the second lateral direction; applying a first compressive force to a first set of opposing sides of the load along the first lateral direction and a second compressive force to a second set of opposing sides of the load along the second lateral direction to compress the load to a third length in the first lateral direction and a third width in the second lateral direction; after applying and releasing the first and second compressive forces, wrapping the load with packaging material using a load wrapping apparatus by generating relative rotation between a packaging material dispenser and the load about an axis of rotation; and allowing the load to recover in the first and second lateral directions after wrapping the load such that the load has the first length in the first lateral direction and the first width in the second lateral direction after the load has been wrapped with packaging material.

32. A method of generating a wrapped load having a first length in a first lateral direction and a first width in a second lateral direction that is substantially perpendicular to the first lateral direction, the method comprising: receiving a load that is unwrapped and that has a second length in the first lateral direction and a second width in the second lateral direction; applying a first compressive force to a first set of opposing sides of the load along the first lateral direction and a second compressive force to a second set of opposing sides of the load along the second lateral direction to compress the load to a third length in the first lateral direction and a third width in the second lateral direction; while applying the first and second compressive forces, wrapping the load with packaging material using a load wrapping apparatus by generating relative rotation between a packaging material dispenser and the load about an axis of rotation; and allowing the load to recover in the first and second lateral directions after wrapping the load such that the load has the first length in the first lateral direction and the first width in the second lateral direction after the load has been wrapped with packaging material.

33. A method of generating a wrapped load having a first length in a first lateral direction and a first width in a second lateral direction that is substantially perpendicular to the first lateral direction, the method comprising: receiving a load that is unwrapped and that has a second length in the first lateral direction and a second width in the second lateral direction; wrapping the load with packaging material using a load wrapping apparatus by generating relative rotation between a packaging material dispenser and the load about an axis of rotation; after wrapping the load, applying a first compressive force to a first set of opposing sides of the load along the first lateral direction and a second compressive force to a second set of opposing sides of the load along the second lateral direction to compress the load to a third length in the first lateral direction and a third width in the second lateral direction; and allowing the load to recover in the first and second lateral directions after wrapping the load and applying the first and second compressive forces such that the load has the first length in the first lateral direction and the first width in the second lateral direction after the load has been wrapped with packaging material.

34.-41. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIGS. 1A-1C are functional top plan views of an example palletized load, and illustrating a load shaping and wrapping operation consistent with the invention.

[0026] FIG. 2 is a block diagram of one example load shaping and wrapping system consistent with the invention.

[0027] FIG. 3 is a block diagram of another example load shaping and wrapping system consistent with the invention.

[0028] FIG. 4 is a block diagram of yet another example load shaping and wrapping system consistent with the invention.

[0029] FIG. 5 shows a top view of a load wrapping apparatus consistent with the invention.

[0030] FIG. 6 is a schematic view of an example control system for use in the load wrapping apparatus of FIG. 5.

[0031] FIG. 7 is a functional side elevational view of an example load shaping apparatus consistent with the invention.

[0032] FIG. 8 is a perspective view of another example load shaping apparatus consistent with the invention, and including interleaved laterally extending fingers.

[0033] FIG. 9 is a perspective view of another example load shaping apparatus consistent with the invention, and including floating corner members.

[0034] FIG. 10 is a functional perspective view of another example load shaping apparatus consistent with the invention, and integrated with a turntable-type load wrapping apparatus.

[0035] FIG. 11 is a functional perspective view of another example load shaping apparatus consistent with the invention, and including doors for allowing passage of a load into and out of the load shaping apparatus.

DETAILED DESCRIPTION

[0036] Embodiments consistent with the invention may apply compressive forces across opposing sides of a palletized load either before, after, or during stretch wrapping to generate a load having a desirable shape profile once wrapped.

[0037] In particular, as noted above, it is generally desirable in some stretch wrapping applications to generate a wrapped palletized load where the lateral dimensions of the load (e.g., length and/or width) substantially match those of the pallet supporting the load. Doing so maximizes the space utilization during shipping and storage, as well as minimizes scuff damage to loads when pallets are positioned next to one another. In addition, inboard or underhung loads can require lower wrap settings and require special packing material for wrapping, while overhung loads, if sufficiently overhung, can potentially inhibit the ability of adjacent loads to be loaded into or unloaded from a truck in some instances (e.g., where two 48 wide loads are placed in a truck having a 98 wide opening).

[0038] One such application is wrapping bundles of consumer paper products, such as paper towels and toilet paper. Such products are often shipped by palletizing and wrapping multi-unit bundles stacked in multiple layers on a pallet, and without the use of separate cardboard boxes to house the multi-unit bundles. The types of products and the bundling of those products, however, often can limit the maximum wrap force used to wrap the palletized bundles, as excessive wrap force can lead to deformation and/or crushing of the products, particularly at the corners of the load.

[0039] Embodiments consistent with the invention, on the other hand, may use a load shaping operation either before, after or during stretch wrapping to generate a load with a desirable shape profile, including desirable lateral shape and/or dimensions. A load shaping operation, in particular, may include the application of a compressive force across opposing sides of a load that compresses the sides in a lateral direction beyond a desired dimension such that subsequent recovery or relaxation of the load allows the sides of the load to expand partially back to the desirable dimension. In various embodiments, the compressive force may be applied across a single pair of opposing sides, although in other embodiments compressive forces (which may be the same or may be different) may be applied across multiple pairs of opposing sides, e.g., all four sides of a rectangular load. The compressive forces for different pairs of opposing sides may be applied concurrently or sequentially in different embodiments.

[0040] It has been found, in particular, that compression of some types of loads, e.g., loads incorporating multi-unit bundles of consumer paper products, exhibits a significant inelasticity in a recovery stress strain curve, such that by overcompressing a load enables a lower containment force to be used to contain the load with a desired shape profile. It will be appreciated that containment force, as used in the context of the disclosure, generally refers to the cumulative force exerted on a load by the packaging material wrapped around the load. Containment force depends on a number of factors, including the number of layers of packaging material, the thickness, strength and other properties of the packaging material, the amount of pre-stretch applied to the packaging material, and the wrap force applied to the load while wrapping the load. The wrap force, in contrast, is a force that fluctuates as packaging material is dispensed to the load due primarily to the irregular geometry of the load.

[0041] Moreover, it has been found that by compressing a load across opposing sides, rather than around the circumference or girth of the load (as is the case with wrapping packaging material around the load), the containment force may hold the load in a desired shape with reduced crushing forces on the load contents, particularly proximate the corners of the loads. For loads including paper rolls wound about cardboard cores, for example, reduced crushing may be exhibited on the cardboard cores, thereby reducing the likelihood of load damage.

[0042] FIGS. 1A-1C, for example, illustrate an example load shaping and wrapping operation consistent with the invention, and performed on a palletized load 10 including an overhung load of products 12 (e.g., multi-unit bundles) supported by a pallet 14. In this example, it is assumed that it is desirable to generate a wrapped load in which the lateral dimensions of load 12 are substantially equal to the lateral dimensions of pallet 14, although it should be appreciated that the desired lateral dimensions of a wrapped load in other embodiments may not correspond to the lateral dimensions of a pallet, and may be larger or smaller in different embodiments. In addition, it will be appreciated that the relationship between the initial load length, the pallet length, the compressed load length and the desired or final load length in the first lateral direction need not match that of the corresponding widths in the second lateral direction, as, for example, the degree of overhang in one lateral direction may differ from that in the other lateral direction in some instances.

[0043] It may be seen in FIG. 1A, for example, that prior to shaping or wrapping, in a first lateral direction, e.g., a length direction, the load 12 has a length L.sub.i that is greater than a length L.sub.p of pallet 14, and in a second lateral direction, e.g., a width direction, the load 12 has a width W.sub.i that is greater than a width W.sub.p of pallet 14. It will be appreciated that the terms length and width are used herein to refer to orthogonal or perpendicular lateral dimensions of a load, and do not imply any particular orientation of the load, such that, for example, the length of a load could be greater than, the same as, or less than the width of the load in different embodiments.

[0044] FIG. 1B illustrates the application of compressive forces F.sub.L, F.sub.W to opposing sides of load 12. Compressive force F.sub.L, for example, is applied along the first lateral direction (i.e., the length direction) to compress load 12 to a length L.sub.c that is smaller than the length L.sub.p of pallet 14, while compressive force F.sub.W is applied along the second lateral direction (i.e., the width direction) to compress load 12 to a width W.sub.c that is smaller than the width W.sub.p of pallet 14. It will be appreciated that the compressive forces may be applied concurrently or sequentially in different embodiments. Moreover, in some embodiments, a compressive force may be applied only to one pair of opposing sides, e.g., if the dimension of the load in one lateral direction is substantially equal to or less than the dimension of the pallet in that lateral direction. In addition, in some embodiments, it may be desirable to not have the final dimensions of the load be centered within the pallet confines, e.g., using either unequal opposing forces or offsetting the centerline of the load shaping apparatus relative to the centerline of the pallet to provide an offset load footprint.

[0045] FIG. 1C illustrates palletized load 10 after the application of compressive forces F.sub.L and F.sub.W, as well as after wrapping the load with packaging material 16 and allowing load 12 to recover in both lateral directions. It will be appreciated that load 12 has recovered or relaxed to a length L.sub.f that is substantially the same as the length L.sub.p of pallet 14 and a width W.sub.f that is substantially the same as the width W.sub.p of pallet 14. Moreover, due to the inelasticity of the load after compression, the containment force required to maintain the load with the final or desired dimensions is substantially reduced relative to that which would be required were the load wrapped without compressive forces being applied.

[0046] The sequence in which a load is shaped, wrapped, and allowed to recover may vary in different embodiments, and may include load shaping that is performed before, after, or concurrently with load wrapping. FIG. 2, for example, illustrates one example load shaping and wrapping system 20 in which an unwrapped load is generated by a palletizer or unit load former 22 and conveyed by a conveyor 24 to a load shaping apparatus 26 that is configured to apply compressive forces to one or both pairs of opposing sides of the load along one or two lateral directions. The load is then conveyed by a conveyor 28 to a load wrapping apparatus 30 to wrap the load with packaging material by generating relative rotation between a packaging material dispenser and the load about an axis of rotation. The shaped and wrapped load may then be conveyed by a conveyor 32 to an exit point 34 for storage or shipping. Depending on the spring rate of the load, recovery or relaxation of the load may occur for a variable amount of time subsequent to the application of compressive forces, and in some instances, may continue while and/or after the load is wrapped by load wrapping apparatus 30. In addition, it will be appreciated that wrapping of the load may be configured with wrap settings that apply a containment force based on the desired or final lateral dimensions of the load.

[0047] It will also be appreciated that conveyors 24, 28, 32 may be separate conveyors in some embodiments, or may be portions of a single conveyor. In addition, load shaping and/or load wrapping may be performed while the load (and pallet) are supported on a conveyor. Other manners of conveying a load between different machinery or stations may be used in other embodiments.

[0048] FIG. 3, as another example, illustrates a load shaping and wrapping system 40 in which an unwrapped load is generated by a palletizer or unit load former 42 and conveyed by a conveyor 44 to a load wrapping apparatus 46 to wrap the load with packaging material by generating relative rotation between a packaging material dispenser and the load about an axis of rotation. The load is then conveyed by a conveyor 48 to a load shaping apparatus 50 that is configured to apply compressive forces to one or both pairs of opposing sides of the load along one or two lateral directions. The shaped and wrapped load may then be conveyed by a conveyor 52 to an exit point 54 for storage or shipping. In such an embodiment, wrapping of the load may be configured with wrap settings that are configured to apply a desired containment force for the final or desired lateral dimensions of the load (rather than the initial lateral dimensions of the unwrapped load) such that once the wrapped load is shaped via the application of compressive forces, the desired containment force will be achieved.

[0049] FIG. 4, as another example, illustrates a load shaping and wrapping system 60 in which an unwrapped load is generated by a palletizer or unit load former 62 and conveyed by a conveyor 64 to a combined load shaping and wrapping apparatus 66 including both a load shaping apparatus 68 and a load wrapping apparatus 70, whereby the load wrapping apparatus 70 wraps the load with packaging material by generating relative rotation between a packaging material dispenser and the load about an axis of rotation while load shaping apparatus 68 applies compressive forces to one or both pairs of opposing sides of the load along one or two lateral directions. The shaped and wrapped load may then be conveyed by a conveyor 72 to an exit point 74 for storage or shipping. In such an embodiment, wrapping of the load may again be configured with wrap settings that are configured to apply a desired containment force for the final or desired lateral dimensions of the load to accommodate the recovery or relaxation of the load after shaping and wrapping is complete.

[0050] It will be appreciated that, in some embodiments, when wrapping of the load is performed after or while applying compressive forces, it may be desirable to use a wrap profile that applies a containment force to the load based upon the compressed dimensions of the load during wrapping such that a relatively higher containment force is applied to the load after recovery of the load after wrapping.

[0051] In addition, in some embodiments, when wrapping of the load is performed prior to applying compressive forces, it may be desirable to use a wrap profile that applies a containment force to the load based upon uncompressed dimensions of the load during wrapping such that relatively lower containment force is applied to the load after recovery of the load after applying the compressive force.

[0052] It will also be appreciated that compressive forces may also be applied on the top of a load (i.e., in a generally vertical direction) during a load shaping operation in some embodiments, e.g., to lower the height of the load and/or to otherwise assist in forming a desired load shape. Furthermore, where multiple palletized loads are stacked on top of one another, compressive forces may be applied in a generally vertical direction in some embodiments to lower the overall height of the stacked loads. In addition, in some embodiments, the application of compressive forces in one or more lateral directions may be performed concurrently for two or more palletized loads that are stacked on top of one another. Moreover, in some embodiments, compressive forces may be applied at multiple times, e.g., both before and after wrapping.

[0053] Further details regarding the load wrapping apparatus and the load shaping apparatus used to implement the aforementioned operations are provided below.

Load Wrapping Apparatus Configurations

[0054] Various load wrapping apparatus configurations may be used in various embodiments of the invention, e.g., to implement any of load wrapping apparatuses 30, 50, and 68 of FIGS. 2-4. For example, FIG. 5 illustrates a rotating arm-type wrapping apparatus 100, which includes a roll carriage or elevator 102 mounted on a rotating arm 104. Roll carriage 102 may include a packaging material dispenser 106. Packaging material dispenser 106 may be configured to dispense packaging material 108 as rotating arm 104 rotates relative to a load 110 to be wrapped. In an example embodiment, packaging material dispenser 106 may be configured to dispense stretch wrap packaging material. As used herein, stretch wrap packaging material is defined as material having a high yield coefficient to allow the material a large amount of stretch during wrapping. However, it is possible that the apparatuses and methods disclosed herein may be practiced with packaging material that will not be pre-stretched prior to application to the load. Examples of such packaging material include netting, strapping, banding, tape, etc. The invention is therefore not limited to use with stretch wrap packaging material. In addition, as used herein, the terms packaging material, web, film, film web, and packaging material web may be used interchangeably.

[0055] Packaging material dispenser 106 may include a pre-stretch assembly 112 configured to pre-stretch packaging material before it is applied to load 110 if pre-stretching is desired, or to dispense packaging material to load 110 without pre-stretching. Pre-stretch assembly 112 may include at least one packaging material dispensing roller, including, for example, an upstream dispensing roller 114 and a downstream dispensing roller 116. It is contemplated that pre-stretch assembly 112 may include various configurations and numbers of pre-stretch rollers, drive or driven roller and idle rollers without departing from the spirit and scope of the invention.

[0056] The terms upstream and downstream, as used in this application, are intended to define positions and movement relative to the direction of flow of packaging material 108 as it moves from packaging material dispenser 106 to load 110. Movement of an object toward packaging material dispenser 106, away from load 110, and thus, against the direction of flow of packaging material 108, may be defined as upstream. Similarly, movement of an object away from packaging material dispenser 106, toward load 110, and thus, with the flow of packaging material 108, may be defined as downstream. Also, positions relative to load 110 (or a load support surface 118) and packaging material dispenser 106 may be described relative to the direction of packaging material flow. For example, when two pre-stretch rollers are present, the pre-stretch roller closer to packaging material dispenser 106 may be characterized as the upstream roller and the pre-stretch roller closer to load 110 (or load support 118) and further from packaging material dispenser 106 may be characterized as the downstream roller.

[0057] A packaging material drive system 120, including, for example, an electric motor 122, may be used to drive dispensing rollers 114 and 116. For example, electric motor 122 may rotate downstream dispensing roller 116. Downstream dispensing roller 116 may be operatively coupled to upstream dispensing roller 114 by a chain and sprocket assembly, such that upstream dispensing roller 114 may be driven in rotation by downstream dispensing roller 116. Other connections may be used to drive upstream roller 114 or, alternatively, a separate drive (not shown) may be provided to drive upstream roller 114. Moreover, in some embodiments the roll of packaging material 108 may be undriven and may rotate freely, while in other embodiments the roll may be driven, e.g., by biasing a surface of the roll against upstream dispensing roller 114 or another driven roller, or by driving the roll directly.

[0058] Downstream of downstream dispensing roller 116 may be provided one or more idle rollers 124, 126 that redirect the web of packaging material, with the most downstream idle roller 126 effectively providing an exit point 128 from packaging material dispenser 102, such that a portion 130 of packaging material 108 extends between exit point 128 and a contact point 132 where the packaging material engages load 110 (or alternatively contact point 132 if load 110 is rotated in a counter-clockwise direction).

[0059] Load wrapping apparatus 100 also includes a relative rotation assembly 134 configured to rotate rotating arm 104, and thus, packaging material dispenser 106 mounted thereon, relative to load 110 as load 110 is supported on load support surface 118. Relative rotation assembly 134 may include a rotational drive system 136, including, for example, an electric motor 138. It is contemplated that rotational drive system 136 and packaging material drive system 120 may run independently of one another. Thus, rotation of dispensing rollers 114 and 116 may be independent of the relative rotation of packaging material dispenser 106 relative to load 110. This independence allows a length of packaging material 108 to be dispensed per a portion of relative revolution that is neither predetermined nor constant. Rather, the length may be adjusted periodically or continuously based on changing conditions. In other embodiments, however, packaging material dispenser 106 may be driven proportionally to the relative rotation, or alternatively, tension in the packaging material extending between the packaging material dispenser and the load may be used to drive the packaging material dispenser.

[0060] Load wrapping apparatus 100 may further include a lift assembly 140. Lift assembly 140 may be powered by a lift drive system 142, including, for example, an electric motor 144, that may be configured to move roll carriage 102 vertically relative to load 110. Lift drive system 142 may drive roll carriage 102, and thus packaging material dispenser 106, generally in a direction parallel to an axis of rotation between the packaging material dispenser 106 and load 110 and load support surface 118. For example, for load wrapping apparatus 100, lift drive system 142 may drive roll carriage 102 and packaging material dispenser 106 upwards and downwards vertically on rotating arm 104 while roll carriage 102 and packaging material dispenser 106 are rotated about load 110 by rotational drive system 136, to wrap packaging material spirally about load 110.

[0061] One or more of downstream dispensing roller 116, idle roller 124 and idle roller 126 may include a corresponding sensor 146, 148, 150 to monitor rotation of the respective roller. In particular, rollers 116, 124 and/or 126, and/or packaging material 108 dispensed thereby, may be used to monitor a dispense rate of packaging material dispenser 106, e.g., by monitoring the rotational speed of rollers 116, 124 and/or 126, the number of rotations undergone by such rollers, the amount and/or speed of packaging material dispensed by such rollers, and/or one or more performance parameters indicative of the operating state of packaging material drive system 120, including, for example, a speed of packaging material drive system 120. The monitored characteristics may also provide an indication of the amount of packaging material 108 being dispensed and wrapped onto load 110. In addition, in some embodiments a sensor, e.g., sensor 148 or 150, may be used to detect a break in the packaging material.

[0062] Load wrapping apparatus also includes an angle sensor 152 for determining an angular relationship between load 110 and packaging material dispenser 106 about a center of rotation 154. Angle sensor 152 may be implemented, for example, as a rotary encoder, or alternatively, using any number of alternate sensors or sensor arrays capable of providing an indication of the angular relationship and distinguishing from among multiple angles throughout the relative rotation, e.g., an array of proximity switches, optical encoders, magnetic encoders, electrical sensors, mechanical sensors, photodetectors, motion sensors, etc. The angular relationship may be represented in some embodiments in terms of degrees or fractions of degrees, while in other embodiments a lower resolution may be adequate. It will also be appreciated that an angle sensor consistent with the invention may also be disposed in other locations on load wrapping apparatus 100, e.g., about the periphery or mounted on arm 104 or roll carriage 102. In addition, in some embodiments angular relationship may be represented and/or measured in units of time, based upon a known rotational speed of the load relative to the packaging material dispenser, from which a time to complete a full revolution may be derived such that segments of the revolution time would correspond to particular angular relationships. Other sensors may also be used to determine the height and/or other dimensions of a load, among other information.

[0063] Additional sensors, such as a load distance sensor 156 and/or a film angle sensor 158, may also be provided on load wrapping apparatus 100. Load distance sensor 156 may be used to measure a distance from a reference point to a surface of load 110 as the load rotates relative to packaging material dispenser 106 and thereby determine a cross-sectional dimension of the load at a predetermined angular position relative to the packaging material dispenser. In one embodiment, load distance sensor 156 measures distance along a radial from center of rotation 154, and based on the known, fixed distance between the sensor and the center of rotation, the dimension of the load may be determined by subtracting the sensed distance from this fixed distance. Sensor 156 may be implemented using various types of distance sensors, e.g., a photoeye, proximity detector, laser distance measurer, ultrasonic distance measurer, electronic rangefinder, and/or any other suitable distance measuring device. Exemplary distance measuring devices may include, for example, an IFM Effector 01D100 and a Sick UM30-213118 (6036923).

[0064] Film angle sensor 158 may be used to determine a film angle for portion 130 of packaging material 108, which may be relative, for example, to a radial (not shown in FIG. 5) extending from center of rotation 154 to exit point 128 (although other reference lines may be used in the alternative). In one embodiment, film angle sensor 158 may be implemented using a distance sensor, e.g., a photoeye, proximity detector, laser distance measurer, ultrasonic distance measurer, electronic rangefinder, and/or any other suitable distance measuring device. In one embodiment, an IFM Effector 01D100 and a Sick UM30-213118 (6036923) may be used for film angle sensor 158. In other embodiments, film angle sensor 158 may be implemented mechanically, e.g., using a cantilevered or rockered follower arm having a free end that rides along the surface of portion 130 of packaging material 108 such that movement of the follower arm tracks movement of the packaging material. In still other embodiments, a film angle sensor may be implemented by a force sensor that senses force changes resulting from movement of portion 130 through a range of film angles, or a sensor array (e.g., an image sensor) that is positioned above or below the plane of portion 130 to sense an edge of the packaging material.

[0065] In other embodiments, some or all of sensors 146, 148, 150, 152, 156, 158 may be omitted.

[0066] Load wrapping apparatus 100 may also include additional components used in connection with other aspects of a wrapping operation. For example, a clamping device 159 may be used to grip the leading end of packaging material 108 between wrap operations or cycles. In addition, a conveyor (not shown) may be used to convey loads to and from load wrapping apparatus 100. Other components commonly used on a load wrapping apparatus will be appreciated by one of ordinary skill in the art having the benefit of the instant disclosure.

[0067] An example schematic of a control system 160 for load wrapping apparatus 100 is shown in FIG. 6. Motor 122 of packaging material drive system 120, motor 138 of rotational drive system 136, and motor 144 of lift drive system 142 may communicate through one or more data links 162 with a rotational drive variable frequency drive (VFD) 164, a packaging material drive VFD 166, and a lift drive VFD 168, respectively. Rotational drive VFD 164, packaging material drive VFD 166, and lift drive VFD 168 may communicate with controller 170 through a data link 172. It should be understood that rotational drive VFD 164, packaging material drive VFD 166, and lift drive VFD 168 may produce outputs to controller 170 that controller 170 may use as indicators of rotational movement.

[0068] Controller 170 in the embodiment illustrated in FIG. 6 is a local controller that is physically co-located with the packaging material drive system 120, rotational drive system 136 and lift drive system 142. Controller 170 may include hardware components and/or software program code that allow it to receive, process, and transmit data. It is contemplated that controller 170 may be implemented as a programmable logic controller (PLC), or may otherwise operate similar to a processor in a computer system. Controller 170 may communicate with an operator interface 174 via a data link 176. Operator interface 174 may include a display or screen and controls that provide an operator with a way to monitor, program, and operate load wrapping apparatus 100. For example, an operator may use operator interface 174 to enter or change predetermined and/or desired settings and values, or to start, stop, or pause the wrap operation. Controller 170 may also communicate with one or more sensors, e.g., sensors 152 and 156, among others, through a data link 178 to allow controller 170 to receive feedback and/or performance-related data during wrapping, such as roller and/or drive rotation speeds, load dimensional data, etc. It is contemplated that data links 162, 172, 176, and 178 may include any suitable wired and/or wireless communications media known in the art.

[0069] Controller 170 may also be used to control other aspects of a load shaping and wrapping system, e.g., a load shaping apparatus 180 and/or one or more conveyors 182. In other embodiments, however, these components may be separately controlled, e.g., by other controllers, which in some instances may be in communication with controller 170.

[0070] For the purposes of the invention, controller 170 may represent practically any type of computer, computer system, controller, logic controller, or other programmable electronic device, and may in some embodiments be implemented using one or more networked computers or other electronic devices, whether located locally or remotely with respect to the various drive systems 120, 136 and 142 of load wrapping apparatus 100.

[0071] Controller 170 typically includes a central processing unit including at least one microprocessor coupled to a memory, which may represent the random access memory (RAM) devices comprising the main storage of controller 170, as well as any supplemental levels of memory, e.g., cache memories, non-volatile or backup memories (e.g., programmable or flash memories), read-only memories, etc. In addition, the memory may be considered to include memory storage physically located elsewhere in controller 170, e.g., any cache memory in a processor in CPU 52, as well as any storage capacity used as a virtual memory, e.g., as stored on a mass storage device or on another computer or electronic device coupled to controller 170. Controller 170 may also include one or more mass storage devices, e.g., a floppy or other removable disk drive, a hard disk drive, a direct access storage device (DASD), an optical drive (e.g., a CD drive, a DVD drive, etc.), and/or a tape drive, among others. Furthermore, controller 170 may include an interface 190 with one or more networks 192 (e.g., a LAN, a WAN, a wireless network, and/or the Internet, among others) to permit the communication of information to the components in load wrapping apparatus 100 as well as with other computers and electronic devices, e.g. computers such as a desktop computer or laptop computer 194, mobile devices such as a mobile phone 196 or tablet 198, multi-user computers such as servers or cloud resources, etc. Controller 170 operates under the control of an operating system, kernel and/or firmware and executes or otherwise relies upon various computer software applications, components, programs, objects, modules, data structures, etc. Moreover, various applications, components, programs, objects, modules, etc. may also execute on one or more processors in another computer coupled to controller 170, e.g., in a distributed or client-server computing environment, whereby the processing required to implement the functions of a computer program may be allocated to multiple computers over a network.

[0072] In general, the routines executed to implement the embodiments of the invention, whether implemented as part of an operating system or a specific application, component, program, object, module, or sequence of instructions, or even a subset thereof, will be referred to herein as computer program code, or simply program code. Program code typically comprises one or more instructions that are resident at various times in various memory and storage devices in a computer, and that, when read and executed by one or more processors in a computer, cause that computer to perform the steps necessary to execute steps or elements embodying the various aspects of the invention. Moreover, while the invention has and hereinafter will be described in the context of fully functioning controllers, computers and computer systems, those skilled in the art will appreciate that the various embodiments of the invention are capable of being distributed as a program product in a variety of forms, and that the invention applies equally regardless of the particular type of computer readable media used to actually carry out the distribution.

[0073] Such computer readable media may include computer readable storage media and communication media. Computer readable storage media is non-transitory in nature, and may include volatile and non-volatile, and removable and non-removable media implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules or other data. Computer readable storage media may further include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid state memory technology, CD-ROM, digital versatile disks (DVD), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and which can be accessed by controller 170. Communication media may embody computer readable instructions, data structures or other program modules. By way of example, and not limitation, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above may also be included within the scope of computer readable media.

[0074] Various program code described hereinafter may be identified based upon the application within which it is implemented in a specific embodiment of the invention. However, it should be appreciated that any particular program nomenclature that follows is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. Furthermore, given the typically endless number of manners in which computer programs may be organized into routines, procedures, methods, modules, objects, and the like, as well as the various manners in which program functionality may be allocated among various software layers that are resident within a typical computer (e.g., operating systems, libraries, API's, applications, applets, etc.), it should be appreciated that the invention is not limited to the specific organization and allocation of program functionality described herein.

[0075] In the discussion hereinafter, the hardware and software used to control load wrapping apparatus 100 is assumed to be incorporated wholly within components that are local to load wrapping apparatus 100 illustrated in FIGS. 5-6, e.g., within components 162-178 described above. It will be appreciated, however, that in other embodiments, at least a portion of the functionality incorporated into a wrapping apparatus may be implemented in hardware and/or software that is external to the aforementioned components. For example, in some embodiments, some user interaction may be performed using an external device such as a networked computer or mobile device, with the external device converting user or other input into control variables that are used to control a wrapping operation. In other embodiments, user interaction may be implemented using a web-type interface, and the conversion of user input may be performed by a server or a local controller for the wrapping apparatus, and thus external to a networked computer or mobile device. In still other embodiments, a central server may be coupled to multiple wrapping stations to control the wrapping of loads at the different stations. As such, the operations of receiving user or other input, converting the input into control variables for controlling a wrap operation, initiating and implementing a wrap operation based upon the control variables, providing feedback to a user, etc., may be implemented by various local and/or remote components and combinations thereof in different embodiments. In some embodiments, for example, an external device such as a mobile device, a networked computer, a server, a cloud service, etc. may generate a wrap model that defines the control variables for controlling a wrap operation for a particular load, and that wrap model may then be communicated to a wrapping apparatus and used by a controller therefor to control a dispense rate during a wrap operation. As such, the invention is not limited to the particular allocation of functionality described herein.

[0076] Moreover, the manner in which controller 170 generates various wrap settings for generating a desired wrap profile for a load, e.g., for applying a desired containment force to a shaped and wrapped load, may vary in different embodiments, and may be based on various wrap models that are based on load geometry, sensor feedback and/or combinations of same. While various other wrap models may be used, several suitable wrap models are disclosed, for example, in U.S. Pat. No. 10,926,906 to Lancaster et al., which is assigned to the same assignee as the present application, and which is incorporated by reference herein.

[0077] Those skilled in the art will recognize that the example load wrapping apparatus illustrated in FIGS. 5-6 is not intended to limit the present invention. Indeed, those skilled in the art will recognize that other alternative environments may be used without departing from the scope of the invention. For example, it will be appreciated that aspects of the invention may be used in other stretch wrapping machines, including ring-based or turntable-based load wrapping machines. Therefore, the invention is not limited to the specific implementations discussed herein.

Load Shaping Apparatus Configurations

[0078] The manner in which a load shaping operation that applies compressive forces across a load may vary in different embodiments. FIG. 7, for example, illustrates an example load shaping apparatus 200 for performing a load shaping operation on a load 202 supported on a pallet 204 and including a stacked array of compressible multi-unit bundles 206. Load shaping apparatus 200 may be used, for example, to implement any of load shaping apparatuses 26, 50, and 68 of FIGS. 2-4, and includes a plurality of press members 208 positioned adjacent sides 210 of load 202, e.g., four press members (of which three are shown in FIG. 7) for a four sided load.

[0079] Each press member 208 may include a substantially planar surface 212 capable of engaging with a substantial portion of the side of the load to distribute the compressive forces across the side of the load. While the portion of the side of the load that may be contacted by the press member may vary in different embodiments, in some embodiments it may be desirable to contact substantially across at least about 50 percent of the lateral dimension of the uncompressed load, as well as to contact the side proximate a midpoint M thereof. In addition, multiple planar surfaces may be used in each press member in some embodiments, such that the area of a side contacted by a press member need not be contiguous.

[0080] Press members 208 are supported by a support structure 214 facilitating movement of the press members substantially along the two lateral directions (i.e., length and width) to apply compressive forces across opposing sides of a load. In some embodiments, for example, each press member 208 may include a plurality of vertical supports 216 that are slidably supported by rails 218 for linear movement relative thereto, with one or more drives 220, e.g., screw drives, chain drives, belt drives, rack-and-pinion arrangements, linear actuators, etc. used to move the press members into engagement with the sides of the load to apply the desired compressive forces. Drives 220 may be hydraulic, pneumatic, electromagnetic, electromechanical (e.g., using an electric motor), etc., and it will be appreciated that a single drive may be used to drive all four press members in some embodiments, while in other embodiments, two drives may be used to separately drive each pair of opposing press members, or four individual drives may be used to independently drive each press member. Press members may also engage the sides of a load through rotary motion or a combination of linear and rotary motion in some embodiments.

[0081] In addition, in some embodiments, support structure 214 and press members 208 may be configured for substantially vertical movement using a lift assembly 222, thereby enabling the press members to move in a substantially downward direction from a position above a load when the load is placed underneath the press members to perform a load shaping operation, and then be lifted in a substantially upward direction to allow the compressed load to be removed from the load shaping apparatus. Alternatively, press members may be positioned below a load in some embodiments such that the press members may move in a substantially upward direction from a position below a load to perform a load shaping operation, and then be lowered in a substantially downward direction to allow the compressed load to be removed from the load shaping apparatus.

[0082] Load shaping apparatus 224 also includes a controller 224 that controls at least drives 220 and lift assembly 222, and that may also be in communication with one or more sensors, e.g., represented functionally at 226, that provide feedback as to the positions of and/or forces applied by press members 208. In some embodiments, for example, it may be desirable to control press members 208 to apply a compressive force to the opposing sides of a load by moving each press member a respective predetermined distance, whereby sensors 226 may be position sensors used to track the position of each press member in its respective lateral direction. In other embodiments, however, it may be desirable to control press members 208 to apply a compressive force to the opposing sides of a load by moving each press member to apply a predetermined force to its respective side, whereby sensors 226 may be force sensors used to monitor the force applied by each press member.

[0083] It will be appreciated that the predetermined distances and/or forces may be determined empirically or may be calculated based on factors such as initial load lateral dimensions, desired final load laterals dimensions, desired containment force of the wrapped load, compressibility of the load, etc. Calculation of such distances and/or forces will be apparent to those of ordinary skill having the benefit of the instant disclosure.

[0084] FIG. 8, as another example, illustrates an example load shaping apparatus 250 for performing a load shaping operation on a load 252 supported on a pallet 254 and including a stacked array of compressible multi-unit bundles 256. Load shaping apparatus 250 includes a plurality of press members 258 positioned adjacent sides 260 of load 252.

[0085] Each press member 258 may include a substantially planar surface 262 capable of engaging with a substantial portion of the side of the load to distribute the compressive forces across the side of the load. In addition, in order to apply compressive forces across a greater portion of the load, as well as to constrain each corner of the load, each press member 258 may include a plurality of laterally-extending and interleaved fingers 264.

[0086] Press members 258 are supported by a support structure 266 facilitating movement of the press members substantially along the two lateral directions (i.e., length and width) to apply compressive forces across opposing sides of a load. In this embodiment, for example, each press member 258 is supported by a pair of carriages 268 that are configured to roll along rails 270, and that are driven by screw drives 272.

[0087] Other manners of constraining the corners of a load during a load shaping operation may be used in other embodiments. For example, FIG. 9 illustrates a portion of another example load shaping apparatus 300 that includes a plurality of press members 302 driven by a set of screw drives 304. Rather than utilizing interleaved fingers, however, load shaping apparatus 300 includes a plurality of floating corner members 306 that are movably coupled between adjacent press members 302 to ride along lateral tracks 308. Floating corner members 306 generally curve around a vertical bend to conform to the shape of the corner of a load, and move inwardly with the press members as compressive forces are applied to restrict bulging of the corners of the loads during a load shaping operation.

[0088] FIG. 10 next illustrates a load shaping apparatus 350 that is integrated with a load wrapping apparatus 352 to support concurrent load shaping and wrapping, e.g., as described above in connection with FIG. 4. In this embodiment, load wrapping apparatus 352 is a turntable-type load wrapping apparatus including a turntable 354 supporting a load 356 and configured to rotate about an axis of rotation R to generate relative rotation between the load and a packaging material dispenser 358 that dispenses a web of packaging material 360 used to wrap the load.

[0089] Load shaping apparatus 350 includes a plurality of press members 362 positioned adjacent sides of the load, and load shaping apparatus 350 is movable in a generally vertical direction (e.g., substantially parallel to axis of rotation R, and represented by arrow 364) in order to position press members 362 adjacent to the sides of the load prior to wrapping, such that compressive forces may be applied to the sides of the load and held during the wrapping operation, and such that at least a portion of the press members is wrapped with packaging material. Upon completion of the wrapping operation, the compressive forces applied by press members 362 may be released, and load shaping apparatus 350 may move upwardly to withdraw the press members from the sides of the load, thereby releasing the packaging material onto the sides of the load. It will be appreciated that various techniques for facilitating the withdrawal of the press members after wrapping may be used, e.g., the use of low friction surfaces and/or reduced thicknesses for the press members, as well as the use of a structure 366 that compresses, applies a generally vertical force to, or otherwise engages the load during the withdrawal of the press members to restrict lifting of the load while withdrawing the press members. In some embodiments, structure 366 may apply a downward force, while in other embodiments, an alternate structure may be used to engage the pallet or another portion of the load (e.g., from a position below the load) to restrict lifting of the load.

[0090] FIG. 11 next illustrates an example load shaping apparatus 400 for performing a load shaping operation on a palletized load 402 while supported on a conveyor 404. In this embodiment, rather than being movable generally vertically in order to engage and/or disengage with a load, load shaping apparatus includes one or more press members 406 configured with one or more doors 408 that are movable, e.g., via pivoting or sliding, between open and closed positions to allow for unrestricted movement of load 402 along conveyor 404 into and out of a load shaping position. Additional press members 410, which lack any such doors, may also be used adjacent the load and conveyor 404 to apply compressive forces in the lateral direction that is generally perpendicular to the direction of movement of the load along the conveyor.

[0091] Thus, prior to applying compressive forces to a load during a load shaping operation, one or more upstream doors 408 of load shaping apparatus 400 may be moved to an open position to allow load 402 to be conveyed into a position adjacent press members 410. Then, doors 408 may be returned to a closed position, and may be used, e.g., any of the various manners discussed above, to apply compressive forces to the load in the lateral direction generally corresponding to the conveying direction of the conveyor. At this time, press members 410 may also be actuated to apply compressive forces to the other pair of opposing sides of the load. Then, after applying the compressive forces, one or more downstream doors 408 of load shaping apparatus 400 may be moved to an open position to allow load 402 to be conveyed out of load shaping apparatus 400.

[0092] It will be appreciated that, while certain features may be discussed herein in connection with certain embodiments and/or in connection with certain figures, unless expressly stated to the contrary, such features generally may be incorporated into any of the embodiments discussed and illustrated herein. Moreover, features that are disclosed as being combined in some embodiments may generally be implemented separately in other embodiments, and features that are disclosed as being implemented separately in some embodiments may be combined in other embodiments, so the fact that a particular feature is discussed in the context of one embodiment but not another should not be construed as an admission that those two embodiments are mutually exclusive of one another. Various additional modifications may be made to the illustrated embodiments consistent with the invention. Therefore, the invention lies in the claims hereinafter appended.